[0001] The present invention relates to a method of alerting drivers of vehicles, and a
warning arrangement for warning drivers of vehicles.
Background art
[0002] It is important to some situations that emergency vehicles such as police cars, fire
trucks, ambulances and the like reach their destination as fast as possible. Thus,
such emergency vehicles can make nearby vehicles aware of their presence by flashing
light and a siren emitting an audio signal from the emergency vehicles so that nearby
drivers of vehicles can see and hear the signals from the emergency vehicle and pull
over to let the vehicle pass. This solution has shown to not always be sufficient
in that e.g. loud music or another audio signal from a radio receiver inside nearby
vehicles and/or inattentive drivers do not always hear or see the emergency vehicle
in due time to react correctly. Also, the emitted audio signal and the flashing lights
limit the area that the emergency vehicle can cover to warn relevant drivers of vehicles
about the presence of a nearby emergency vehicle.
[0003] Also, it may generally be advantageous to warn drivers of vehicles of traffic issues
at local geographical areas.
[0004] US 2003/0141990 discloses an emergency vehicle or a tracking centre transmitting position information
to nearby vehicles, e.g. by use of GPS information, and a receiver of the nearby vehicles
comprises means for analysing the position data.
[0005] GB2330989 discloses an emergency vehicle having RDS transmitter for transmitting a warning
signal to vehicles nearby.
[0006] EP0774147 discloses an emergency vehicle that transmits signals to nearby vehicles, e.g. by
means of utilizing parts from a RDS (Radio Data System) function. The signal from
the emergency vehicle is transmitted at a tunable frequency of the receiver in the
vehicle.
[0007] It is e.g. an object of the invention to enhance operation possibilities and/or provide
further advantages in relation to warning drivers of vehicles.
Brief description of the invention
[0008] The invention relates to a method of warning drivers of vehicles, said method comprising:
transmitting a traffic bulletin signal at a first predefined radio channel to one
or more radio receivers of said vehicles, which one or more radio receivers comprise
a Radio Data System facility, and
transmitting at least one further radio signal being an interception radio signal,
wherein said interception radio signal comprises information in the Radio Data System
frequency range of a second radio channel being different from the first radio channel,
wherein said information is different from information in the Radio Data System frequency
range of a third radio signal transmitted from an external broadcasting station at
said second radio channel, and
wherein said information is configured so as to manipulate said radio receivers to
automatically tune said radio receivers to said first radio channel to receive said
traffic bulletin signal.
[0009] By the present invention, several advantages may be obtained. For example, by the
above, emergency vehicles and other arrangements such as stationary arrangements located
e.g. temporarily near a road, may transmit the interception signal(s) and traffic
announcement signal to warn the drivers of nearby vehicles of e.g. traffic-related
matter relevant to the local geographical area. So by the present invention it may
be obtained that receivers e.g. not comprising an RDS feature and/or receivers being
set to not receive RDS traffic information will not shift to receive the traffic bulletin
signal. Hence unintended disturbance of receivers within range of the interception
signal and/or traffic bulletin signal may be avoided. On the other hand, receivers
where certain RDS features are enabled will be able to automatically shift to and
receive a traffic bulleting of the traffic bulletin signal.
[0010] It may furthermore be achieved that listeners listening to a radio program (or a
CD, a an audio data file such as MP3 files, WAW files and/or the like) may not notice
that the receiver is receiving the interception signal, and the listeners hence will
first notice a change when the receiver actually transmits a traffic bulletin of the
traffic bulletin signal. Hence, unintended disturbance of an audio signal that the
listeners may listen to may be avoided. This is preferably achieved by that the interception
signal transmitted at the second channel does not comprise any audio signal in the
S-band and/or M-band of the interception signal that will disturb the audio part of
a radio signal that is transmitted at the same (second) channel by an eexternal broadcasting
station and to be received at the same or near the geographical location that the
traffic bulletin signal and/or same geographical location.
[0011] It is understood that for the term Radio Data System (RDS) is both to be understood
the Radio Data System utilized e.g. in Europe, and the Radio Broadcast Data System
(RBDS) being the official name used for the U.S. version of RDS. It is furthermore
that the Radio Data System may also be referred to as "RDS" in the present document.
[0012] The channels that are used for transmittance of the interception signal and the traffic
bulletin signal are different. For example, a receiver of a vehicle may be tuned to
the channel of a radio program broadcasted on the second radio channel so that a listener
in the vehicle can hear the audio signal of the radio program. Hence, to facilitate
that the receiver(s) shifts to the first radio channel of the traffic bulletin signal,
the interception signal is transmitted at the second radio channel which the receiver
is tuned to. As one example, a receiver may be tuned to a radio channel at e.g. 100
MHz so that a radio program broadcasted at the S-band and/or M-band at this channel
can be listened to by the driver, and hence the interception signal may hence be transmitted
at the same channel, i.e. 100 Mhz.
[0013] Due to the information in the Radio Data System frequency range of the interception
signal, the receiver may be manipulated to automatically shift to the first channel
so that the receiver receive the traffic bulletin signal and so that a traffic bulletin
of the traffic bulletin signal is given to the driver of the vehicle. The first channel
is preferably an "empty" radio channel that is not used for broadcasting radio programs
from stationary broadcasting arrangements at and near the geographical location from
where the interception signal(s) and traffic bulletin signals(s) are transmitted.
[0014] It is to be understood that the interception signal and the traffic bulletin signal
are transmitted within the tunable FM range of the receivers, for example 87.5 to
108.0 MHz, 88.0 to 108.0 MHz, 76.0 to 90 MHz and/or the like dependent on where the
present invention is to be used.
[0015] Also, as described above, the information in the Radio Data System frequency of the
interception signal may be different from information in the Radio Data System frequency
range of the third radio signal transmitted from an external broadcasting station
at the second radio channel. Hereby is understood that a radio receiver of a vehicle
originally tuned to receive the third signal that may comprise RDS data may upon receipt
of the interception signal be manipulated by the interception signal to shift to the
traffic bulletin signal due to the information in the interception signal. So at least
some of the information in the RDS band of the interception signal may be different
from the information in the RDS band of the third signal to induce the receiver(s)
to tune to the channel of the traffic bulletin signal. For example by manipulating
one or more EON features of the RDS information in the interception signal, by the
interception signal comprising a noise signal in the RDS band and/or the like.
[0016] In a preferred aspect of the invention, said method may comprise that the interception
signal is configured so that radio receivers without Radio Data System facilities
and receiving said interception signal continue to receive and broadcast an audio
signal of said third signal.
[0017] Hence, a disturbance of audio signals of the third signal may be omitted where such
disturbances are inappropriate. For example, receivers not containing a RDS facility
are often stationary radio receivers where a listener may have no interest in listening
to local traffic-related matters at local geographical areas. Also, it may be an advantage
at local areas where a warning arrangement is arranged stationary at/near a road.
This may e.g. be achieved by the interception signal not comprising signals in the
S-band and/or M-band of the interception signal that will disturb the audio signal
of the third signal. This may e.g. by filtering the interception signal by a filter
arrangement comprising e.g. a bandpass filter so that signals in the S-band and/or
M-band of the interception signal are removed or at least severely reduced.
[0018] In a preferred aspect of the invention, said method may comprise that the information
in the Radio Data System frequency range of said interception signal may be configured
so that radio receivers with a Radio Data System Traffic Announcement facility disabled
and receiving said interception signal continue to receive and broadcast an audio
signal of said third signal while other receivers with the Radio Data System Traffic
Announcement facility enabled and receiving said interception signal automatically
tune to said first radio channel to receive said traffic bulletin signal.
[0019] This may e.g. be performed by the interception signal comprising RDS information
such as a configuration of TA and TP flags set so as to have receivers with the Radio
Data System Traffic Announcement facility turned on and receiving the interception
signal to tune to the traffic bulletin signal. Hence receivers with this function
disabled may not be disturbed unintentionally by the receiver shifting to the channel
of the traffic bulletin signal upon receipt and processing of the information in the
Radio Data System frequency range.
[0020] In advantageous aspects of the invention, said method may comprise that the information
in the Radio Data System frequency range of said interception signal is configured
so that radio receivers with a Radio Data System AF facility disabled and receiving
said interception signal continue to receive and broadcast an audio signal of said
third signal, while other receivers with a Radio Data System AF enabled and receiving
said interception signal automatically tune to said first radio channel to receive
said traffic bulletin signal.
[0021] The above aspects relating to the Radio Data System AF and/or the Radio Data System
Traffic Announcement facility may e.g. be achieved by proper manipulation of the RDS
facility of existing RDS receivers. E.g. by adding RDS data and/or noise to the RDS
band of the interception signal(s) as described in more details later on.
[0022] In general, making it optional if the traffic bulletin signal is to be tuned to may
be advantageous.
[0023] In preferred aspects of the invention, the method may comprise that the interception
signal is configured so that that the information of an audio signal of said third
signal is derivable from the output of receivers continuing to receive and broadcast
an audio signal of said third signal while at the same time receiving said interception
signal.
[0024] The audio signal of the third signal is preferably derivable in a way so that a listener
by means of a receiver listening to the audio signal of the third signal from the
external broadcaster would be able to continue to listen to the audio signal if the
receiver does not comprises a RDS facility and/or with a RDS facility set so the receiver
does not tune to the traffic bulletin signal upon receipt of the interception signal.
Hence, a listener would not be annoyed by traffic bulletins that are not relevant
to the listener and/or are deselected.
[0025] Alternatively, a measuring instrument connected to the audio output of the receiver
receiving the interception signal but adapted so it does not tune to the traffic bulletin
signal may be utilized for comparing the output from the receiver with the audio signal
from the third signal to test if the audio signal is derivable.
[0026] In advantageous aspects of the present invention, method may comprise that the interception
signal provides interference in the FM S-band and/or M-band of the interception signal
that is at least 20dB such as 30 dB for example 40dB below an audio signal of said
third signal registered by said receiver (3).
[0027] Hence, an audio signal of the third signal in the S-band or M-band may be broadcasted
to the driver in an acceptable audio quality while the receiver at the same time receives
the interception signal at the same channel.
[0028] In aspects of the invention, the method may comprise that the first radio channel
and said second radio channel are spaced apart in transmission frequency by at least
200 kHz.
[0029] The FM broadcasting range (e.g. 88-108 MHz) uses a channel spacing of 200 kHz, with
a maximum frequency deviation of 75 kHz, leaving a 25 kHz guard band above the highest
and below the lowest frequency to reduce interaction with other channels.
[0030] In aspects of the present invention, said method may comprise that the interception
radio signal is established based on a predefined carrier frequency, wherein said
predefined carrier frequency is modulated with said information in the Radio Data
System frequency band.
[0031] This may be an advantageous way of establishing the interception signal. The interception
signal may for example be established digitally by digital means such as comprising
a digital synthesiser or signal processor, by means of an analog signal generator
and/or signal generators and/or by any other suitable means, by adjusting a frequency
deviation as described in more details later on and/or the like.
[0032] In aspects of the invention, the said method may comprise that the interception signal
is adapted so that the energy of the carrier and eventual M- and S- signals of said
transmitted interception signal is reduced compared to the un-modulated carrier.
[0033] This reduction may be performed by adjusting the modulation index in e.g. the RDS
frequency range, by means of filtering of the interception signal before transmittance
and/or the like.
[0034] In preferred aspects of the invention, the said method may comprise that the modulation
index of said interception signal targeting the RDS information is preselected to
a value so that the energy of a carrier of said transmitted interception signal is
reduced while the energy in the sidebands from the RDS information in the interception
signal is maintained.
[0035] It has come to the knowledge of the inventor that the RDS signal is very sensitive
to disturbance, and also, the inventor has realized that the Bessel function indicates
that at certain levels of FM-modulation of the carrier, the carrier of the transmitted
signal may be significantly reduced so that the signal substantially only comprise
energy in the side bands. Hence, the radiated power of the interception signal may
be significantly reduced while the receivers still registers the information in the
RDS band of the interception signal.
[0036] It may e.g. be possible hereby to reduce the transmission power by about 5 dB such
as 10dB, for example 20dB or even more.
[0037] By the term targeting as described above is to be understood that the RDS range at
e.g. 57 kHz ± e.g. 2.5 kHz and/or 3.0 kHz may be utilized.
[0038] In advantageous aspects, modulation index is selected so that the energy of the carrier
of the interception signal is reduced to less than 60% such as less that 35% for example
less that 25% such as less than 10% compared to the un-modulated carrier.
[0039] In aspects, a modulation index of said interception signal may for example be selected
to a value between 1.8-3.0, between 5.0-6.0, or between 8.0-9.0. At for example the
mentioned levels of the modulation index, the carrier will be significantly reduced
and hence the total radiated power of the interception signal may be reduced.
[0040] In aspects of the invention, the method may comprise that a filter arrangement reduces
and/or removes frequency components in the S-band and/or M-band of said interception
signal.
[0041] The filter arrangement may in aspects comprise a band pass filter with a cut off
frequency so as to only allow energy in the RDS range to be transmitted, it may comprise
a high-pass filter with a cut off frequency allowing said RDS information to be added
to be contained in the interception signal while energy in the S-band and/or M-band
of said broadcasted interception signal is reduced or avoided etc. It is to be understood
that the filter arrangement in embodiments may comprise any suitable analog and/or
digital filters or other suitable arrangements facilitating transmitting an interception
signal comprising energy in the S-band and/or M-band that allows radios not tuned
to the traffic announcement signal but still receiving the interception signal to
broadcast an audio signal of the third signal in the S-band and/or M-band at a level
that can be detected by a listener and/or suitable measuring devices.
[0042] In aspects of the invention, the said method may comprise that the relationship between
energy in the Radio Data System frequency band of said transmitted interception radio
signal and the energy at a predefined carrier frequency of said transmitted interception
radio signal is at least 2:1, e.g. at least 10:1, such as at least 100:1, for example
at least 1000:1.
[0043] From the above is understood that there may be significantly more energy in the RDS
band of the interception signal than at the carrier frequency
[0044] In aspects of the invention the said Radio Data System frequency band of said interception
radio signal is located substantially at 57±2.5kHz and/or 57±3.0 kHz.
[0045] In advantageous aspects of the invention, the method comprises that information of
said interception radio signal comprises a noise signal at said Radio Data System
frequency range.
[0046] Some radio receivers of vehicles are adapted to tune to another station when a part
of the signal of the third signal becomes weak. Hence, by adding the noise signal,
the receiver may register this as the RDS information of the third signal becoming
weak, and hence start to try to tune to another channel.
[0047] The noise signal may comprise white noise, grey noise or any other suitable noise
pattern. The noise signal may be established by means of a noise generator and/or
any other suitable means facilitating establishing a noise signal that facilitates
triggering the receivers registering the noise signal to tune to the traffic bulletin
signal.
[0048] In further aspects of the invention, one or more stationary broadcasting stations
transmits channel information and a RDS Program Identification code of said traffic
bulletin signal to said radio receivers so as to enable said receivers to automatically
tune to said traffic bulletin signal when receiving said interception radio signal.
[0049] This information from the broadcasting stations is preferably automatically stored
in e.g. the AF lists of said radio receivers by the broadcaster, so that when for
example the noise signal as described above is registered by the receivers, they will
turn to look in the AF list for an alternative frequency transmitting the same program
and hence be guided to tune to the channel of the traffic bulletin signal instead.
[0050] The reason for this is that when the receivers registers a bad RDS signal as the
noise signal will be interpreted as, the receivers sees this as the radio signal from
the broadcasting station getting to weak/disturbed. Hence, the receivers may look
for an alternative channel in the AF list and would preferably find the channel and
PI code of the traffic bulletin signal. Hence, it is preferred that the PI code of
the traffic bulletin signal is preferably identical to the PI code of the channel
that the receiver is tuned to upon receipt of the interception signal.
[0051] In advantageous aspects of the invention, the method may comprise that said information
of the interception radio signal comprises Radio Data System data.
[0052] For example, the radio system Data may comprise RDS information and commands. Hence,
such a signal may be considered as a kind of spoofing signal where the RDS information
masquerades as RDS information of a stationary broadcaster and hence inducing the
radio receivers receiving the signal to tune to the traffic bulletin signal without
interfering audio signals of the stationary broadcaster or at other broadcasting channels.
[0053] In further aspects of the invention, said interception signal comprises Enhanced
Other Network data of the RDS system.
[0054] The Enhanced other Network (EON) facility of the RDS system provides some opportunities
of having a receiver to temporarily tune to another station to receive a traffic announcement
or another message. Hence, utilizing parts of the EON facility, it may be possible
to manipulate the receivers receiving the interception signal to tune to the channel/frequency
of the traffic bulletin signal.
[0055] In further advantageous aspects of the invention, said interception signal comprises
EON data configured so that receivers with RDS traffic announcement features in EON
enabled will tune to said first predefined radio channel, and wherein receivers with
RDS traffic announcement features in EON disabled will stay tuned to said second channel.
[0056] Hereby, receivers having the TA feature enabled and receiving the interception signal
would try to tune to the channel of the traffic bulletin signal, whereas receivers
having the TA feature disabled and receiving the interception signal may remain tuned
at the second channel.
[0057] In general it is also to be noted that when the traffic bulletin becomes weak (as
seen from the receiver), most RDS receivers will first go back to the originally selected
frequency regardless of PI and may also therefore return to the program before interception.
[0058] In aspects of the invention, the method may comprise that said Radio Data System
data comprises an identification of the broadcast channel of said traffic bulletin
signal to be implemented in an Alternative Frequency list of said radio receivers
[0059] Hereby may be achieved that radio receivers receiving the interception signal will
automatically tune to the broadcast channel of said traffic bulletin signal.
[0060] In advantageous aspects of the present invention, said Radio Data System data may
comprise a program identification code of said traffic bulletin signal.
[0061] Hereby may be achieved that radio receivers receiving the interception signal may
stay tuned to broadcast traffic bulletins of the traffic bulletin signal, in that
the receiver may correlate the program identification code with the program identification
code of the received traffic bulletin signal.
[0062] In further advantageous aspects of the invention, the method may comprise that the
Radio Data System data of the interception signal comprises a TA flag and/or other
EON features indicating a currently active traffic announcement.
[0063] Hence, the interception signal may in this way initiate the receivers receiving the
signal to look for the traffic bulletin signal.
[0064] In aspects of the invention, said Radio Data System data may comprise a RDS TP flag
set so as to indicate that said traffic bulletin signal is considered as transmitting
a traffic announcement.
[0065] This may e.g. be advantageous in relation to utilizing e.g. the EON feature of the
RDS system, in that the TP flag may hence be used for indicating that the traffic
bulletin signal is to be considered as comprising a radio program transmitting traffic
announcements.
[0066] In aspects of the invention, the method may comprise said traffic bulletin signal
comprises RDS data to be received and processed by said receivers.
[0067] This may be advantageous in relation to controlling if the receivers should stay
tuned to the channel of the traffic bulletin system and/or if the receivers e.g. return
to the previous channel.
[0068] In advantageous aspects of the invention, said traffic bulletin signal comprises
a RDS traffic program flag set so as to enable that said one or more radio receivers
consider the traffic bulletin signal as a traffic service signal, and/or a traffic
program flag set so as to ensure that said one or more receivers tuned to receive
the traffic bulletin signal remain to be tuned to the said traffic bulletin signal.
[0069] It may be especially advantageous to have the traffic bulletin signal comprising
RDS information so that the receivers, e.g. as long as the TA flag of the traffic
bulletin signal is set to "1", will stay tuned to the traffic bulletin signal to receive
the traffic bulletin of the traffic bulletin signal. Also, having a TP flag in a traffic
bulletin signal set to "1" may help to have the receivers stay tuned to the channel
of the traffic bulletin signal.
[0070] In an aspect of the invention, said traffic bulletin signal may comprise a RDS PI
code, and wherein a RDS PI code identical to the RDS PI code of the traffic bulletin
signal is stored in said receiver(s) so that the receiver(s), when tuning to the traffic
bulletin signal accepts the PI code of the traffic bulletin signal.
[0071] Radio receivers comprising a RDS facility may be configured for utilizing RDS PI
codes for verifying a traffic program that they tune to. Hence, manipulating such
receivers may e.g. help to have the receivers tune to the traffic bulletin signal.
[0072] In an aspect, the PI code of the traffic bulletin signal may be adapted so as to
be identical to the PI code of the radio program that the receiver was tuned to before
shifting to the channel of the traffic bulletin signal due to receipt of the interception
signal.
[0073] In advantageous aspects of the invention a PI code of the traffic bulletin signal
is stored in the receiver by means of RDS information in radio signals from an external
broadcasting arrangement and/or by means of RDS data in the interception signal.
[0074] Having a PI code of the traffic bulletin signal stored in the receiver by a radio
signal transmitted from an external broadcasting arrangement may e.g. be advantageous
in relation to having the receiver tune rapidly to the channel of the traffic bulletin
signal.
[0075] Having a PI code of the traffic bulletin signal stored in the receiver by RDS data
in the interception signal may e.g. be advantageous to facilitate that the system
may work by a warning arrangement without the need of external broadcasters broadcasting
to specify PI codes of the traffic bulletin system.
[0076] In advantageous aspects of the invention, said method may comprise that scanning
means scan the FM frequency band within the tunable range of said receivers for one
or more channels to be utilized for broadcasting said interception signal and/or said
traffic bulletin signal.
[0077] Hence, one or more interception signals may be transmitted on channels selected based
on the scanning, thus e.g. facilitating local channel adjustment so that the warning
arrangement can fit in to the radio environment at the geographical area where it
is present. This aspect may furthermore be especially relevant where the interception
signal(s) and the traffic bulletin signal are transmitted from a vehicles such as
an emergency vehicle since continuous local channel adjustment of the traffic bulletin
signal and/or the interception signals) may due to the movement of the vehicle.
[0078] It may be advantageous to continuously scan for proper and preferably empty channels
for use for the traffic bulletin signal.
[0079] In aspects of the invention, the method comprises the step of at the location from
where the interception signal is transmitted detecting the signal strength of a signal
from an external broadcasting arrangements at said second channel, and wherein the
signal strength of said interception signal and/or traffic bulletin signal is adapted
based on this scanning.
[0080] Hereby, it may be possible to adapt the signal strength of the interception signal
and/or traffic bulletin signal to avoid unnecessary high transmittance strength of
the interception signal, thus avoiding disturbing receivers at locations where the
traffic bulletin may not be considered relevant.
[0081] In preferred aspects, the scanning may be performed continuously, with a predefined
time interval and/or the like.
[0082] In aspects of the invention a plurality of interception signals may be transmitted
at different channels.
[0083] Hence, receivers tuned to different channels to receive different radio programs
may all be automatically tuned to receive the traffic bulletin signal. This facilitates
that more receivers may shift to receive the traffic bulletin of the traffic bulletin
signal.
[0084] In further aspects of the invention, the method may comprise that the said traffic
announcement signal and said interception signal are transmitted from an emergency
vehicle.
[0085] Hence, drivers of vehicles receiving the traffic bulletin of the traffic bulletin
signal are made aware of the presence of a nearby emergency vehicle e.g. acting on
e.g. an emergency response. Preferably the traffic announcement signal and said interception
signal are transmitted from the same emergency vehicle.
[0086] In aspects of the invention, said traffic bulletin signal(s) and said interception
signal(s) are transmitted from a stationary location.
[0087] This may be relevant in relation to e.g. accidents at roads where authorized personnel
may want to arrange the device to e.g. temporarily warn nearby drivers by the traffic
bulletin signal that they should e.g. slow down and pay attention. This may hence
improve safety of the working personnel at the location of the accident and/or the
drivers of vehicles comprising receivers receiving a traffic bulletin of the traffic
bulletin signal.
[0088] In an aspect of the invention, a positioning arrangement detects a geographical position
and an adjustment of the channel for transmittance of said interception signal and/or
traffic bulletin signal is performed based thereon.
[0089] Hence, an advantageous way of determining proper channels for transmitting the interception
signal and/or traffic bulletin signal may be identified.
[0090] In aspects of the invention the method may furthermore comprise a TCM decoding.
[0091] Hence, such TCM (Traffic Message Channel) information may be utilized in relation
to adapting the interception signal and/or traffic bulletin signal.
[0092] The invention furthermore relates to a warning system for warning drivers of vehicles,
said system comprising:
a plurality of radio receivers arranged at said vehicles, which radio receivers comprise
a Radio Data System facility, and
one or more stationary broadcasting stations configured for transmitting radio signals
at one or more predefined radio frequencies to one or more radio receivers of, said
vehicles, and
a broadcasting arrangement, said broadcasting arrangement being configured for:
transmitting a traffic bulletin signal at a first predefined radio channel to one
or
more radio receivers of said vehicles, which one or more radio receivers comprise
a Radio Data System facility, and
transmitting at least one further radio signal being an interception radio signal,
wherein said interception radio signal comprises information in the Radio Data System
frequency range of a second radio channel being different from the first radio channel,
wherein said information is configured so as to manipulate said radio receivers to
automatically tune said radio receivers to said first radio channel to receive said
traffic bulletin signal.
[0093] Also, the invention relates to a warning system as described above being configured
for operating in accordance with a method according to one or more of the above mentioned
aspects and/or a method according to one or more of the claims of this document.
[0094] Furthermore, the invention relates to a warning arrangement for warning drivers of
vehicles, said warning arrangement being configured for:
transmitting a traffic bulletin signal at a first predefined radio channel to one
or more radio receivers of said vehicles, which one or more radio receivers comprise
a Radio Data System facility, and
transmitting at least one further radio signal being an interception radio signal,
wherein said interception radio signal comprises information in the Radio Data System
frequency range of a second radio channel being different from the first radio channel,
wherein said information is configured so as to manipulate said radio receivers to
automatically tune said radio receivers from a third radio signal broadcasted from
an external, stationary broadcasting station at said second channel to said first
radio channel to receive said traffic bulletin signal.
[0095] Also, the invention relates to a warning arrangement as described above configured
for operating in accordance with a method according to one or more of the above aspects
and/or a system according to one or more of the above aspects, and/or a method according
to one or more of the claims of this document.
[0096] The invention may furthermore relate to a method of warning drivers of vehicles,
said method comprising: transmitting a traffic bulletin signal at a first predefined
radio channel to one or more radio receivers of said vehicles, which one or more radio
receivers comprise a Radio Data System facility, and transmitting at least one further
radio signal being an interception radio signal, wherein said interception radio signal
comprises information in the Radio Data System frequency range of a second radio channel
being different from the first radio channel, wherein said information is configured
so as to manipulate said radio receivers to automatically tune said radio receivers
to said first radio channel to receive said traffic bulletin signal. Also, it is to
be understood that this method may be combined with a method according to one or more
of the above aspects and/or a warning system and/or a warning arrangement according
to one or more of the above aspects, and/or a method according to one or more of the
claims of this document.
[0097] The invention may furthermore also relate to an emergency vehicle comprising a warning
arrangement as disclosed in one or more aspects of this document.
[0098] In general it is to be understood that the present invention in preferred aspects
is utilized for radio receivers in vehicles in the form of, FM (frequency modulation)
radio receivers. Such receivers may furthermore also comprise an AM (Amplitude Modulation)
feature for receiving and broadcasting AM radio signals from stationary broadcasting
arrangements, a DAB (Digital Audio Broadcasting) feature for receiving and broadcasting
DAB radio signals, and/or any other suitable feature for receiving different types
of radio signals. Hence, the RDS feature and FM features of such receivers may be
utilized as described by the present invention. In such embodiments, such receivers
may monitor the RDS information of FM signals and may hence be adapted for shifting
to the radio channel of the traffic bulletin signal upon receipt and processing of
the information in the RDS band of the interception signal, and hence shifting from
an FM signal, AM signal, DAB signal and/or the like to the traffic bulletin signal.
[0099] It is furthermore generally understood that the traffic bulletin signal(s) and/or
interception signal(s) preferably are FM radio signals.
[0100] It is to be understood that the disclosed aspects above may be combined in a multitude
of varieties so as to provide aspects of e.g. a method of warning drivers of vehicles,
a warning system for warning drivers of vehicles and/or a warning arrangement for
warning drivers of vehicles.
Figures
[0101] Aspects of the present disclosure will be described in the following with reference
to the figures in which:
- Fig. 1:
- illustrates an embodiment of the invention according to aspects of the invention,
- fig. 2:
- illustrates a diagrammatic representation of a FM base band signal according to aspects
of the invention,
- fig. 3:
- illustrates an embodiment of an interception signal transmitted from a warning arrangement
according to aspects of the invention,
- fig. 4:
- illustrates a flow-chart relating to embodiments of a process of transmitting an interception
signal and a traffic bulleting signal according to aspects of the invention,
- fig. 5:
- illustrates a flow-chart relating to embodiments of adding a noise signal to an interception
signal according to aspects of the invention,
- fig. 6:
- illustrates a flow-chart relating to embodiments of adding RDS data to an interception
signal according to aspects of the invention.,
- fig. 7:
- illustrates five radio programs where one of these is a radio bulletin signal transmitted
from a warning arrangement according to aspects of the invention.
- fig. 8:
- illustrates an embodiment where multiple interception signals are transmitted at different
radio channels according to aspects of the invention, and
- fig. 9:
- illustrates embodiments of a warning arrangement according to aspects of the invention.
Detailed description of the invention
[0102] Fig 1 illustrates a preferred embodiment of the invention. The warning system of
the present invention system comprises a warning arrangement 10 configured for transmitting
a traffic bulletin signal 2 at a first predefined radio channel to one or more radio
receivers 3 in vehicles 1.
[0103] The warning arrangement 10 is furthermore configured for transmitting a further radio
signal in the form of an interception radio signal 4. The interception radio signal
4 comprises information in the Radio Data System frequency range of a second radio
channel being different from the above mentioned first radio channel of the traffic
bulletin signal. This information of the interception signal 4 may be different from
information in the Radio Data System frequency range of a third radio signal 5 transmitted
from an external broadcasting station 6 at the second radio channel. The said information
of the interception signal 4 is hence configured so as to manipulate radio receivers
3 receiving the interception signal to automatically tune to the first radio channel
to receive the traffic bulletin signal 2.
[0104] As can be seen from fig. 1, the warning arrangement 10 may be placed in an emergency
vehicle 11 such as an ambulance, a fire truck, a police car (and/or police motor cycle)
and/or any other suitable emergency vehicle 11 or other suitable transportation means
so as to warn drivers of nearby vehicles 1 of the emergency vehicle approaching or
being nearby. In embodiments, the warning arrangement 10 may be implemented in a dash-board
of an emergency vehicle 11 and consume power from the power supply of the vehicle
11, it may be arranged in its own casing that may be installed in the emergency vehicle
11 external to the dashboard and may e.g. be connected to the power supply of the
emergency vehicle 11 and/or the like.
[0105] In further embodiments of the invention, the warning arrangement 10 may be located
in e.g. a casing configured for/facilitating being e.g. portable to be temporarily
arranged at a local geographical location and/or it may be configured or being substantially
permanently arranged near a road to warn drivers of approaching vehicles 1 by means
of the radio receiver 3 of the vehicles.
[0106] Also, in embodiments, the warning arrangement may comprise its own power supply in
the form of one or more batteries that may be replaceable and/or rechargeable by a
power supply external to and connected to a power input of the warning arrangement
so as to achieve a stand-alone device.
[0107] So the warning arrangement may be a portable device, it may be a device incorporated
in/to be incorporated in a dashboard, it may be a device for being arranged outdoor
at a stationary location near one or more roads to warn drivers of vehicles and/or
the like.
[0108] The broadcasting station 6 may be a conventional broadcasting station transmitting
radio signals 5 at one or more predefined channels by means of one or more antennas
7. These signals 5 are to be received and processed by radio receivers 1. The radio
signals 5 may e.g. comprise a radio program at a predefined channel such as commercial
radio programs. The radio receivers 3 are hence adapted for identifying and broadcasting
audio signals of the radio signal 5 to listeners such as the driver and passengers
in the vehicle 1. Also, radio receivers 3 comprising a Radio Data System (RDS) facility
may be set to process Radio Data System information in the RDS band of the radio signal
5 (if such a signal is present in the signal 5).
[0109] It is to be understood that the warning arrangement 10 is external to such conventional
broadcasting stations 6.
[0110] The traffic bulleting signal 2 comprises a traffic bulletin e.g. comprising an audio
signal for being broadcasted to the radio receivers 3 tuned to and within the range
of the traffic bulletin signal 2. This audio signal may comprise a siren audio signal,
a prerecorded audio message where a person has recorded an audio message, an audio
signal detected by a microphone connected to the warning arrangement so that drivers
of the emergency vehicle may record/speak messages into the microphone to be broadcasted
substantially in real-time to the nearby drivers to be warned by means of the traffic
bulletin signal 2 as it is registered by the microphone and/or the like.
[0111] It is understood that the channel(s) of both the traffic bulletin signal and the
interception signal are preferably located within the tuneable range of the receivers
3.
[0112] The warning arrangement 10 may be connected to means controlling e.g. a siren and/or
blinking light of the emergency vehicle 11 so that it is automatically turned on to
transmit the signals 2, 4 when the siren and/or blinking light is turned on. In embodiments,
the warning arrangement 10 may also be turned on and off manually by an operator in
e.g. the emergency vehicle.
[0113] In further embodiments, the warning arrangement 10 may be controlled wired or wirelessly,
so that e.g. an operator located at an emergency central or another location may turn
the device on and off from a location remote too the location of the warning arrangement
10. This may e.g. be advantageous in embodiments where the warning arrangement 10
may be configured for be arranged temporarily and/or substantially permanently at
a geographical location. In the following, a more detailed description of advantageous
embodiments of the invention is described.
[0114] As known in the art, FM radio signals for the radio receivers 3 may be modulated
by an audio signal. This signal is conventionally transmitted from a conventional
broadcasting arrangement 6, and comprises a base band signal in a range of about 20
Hz to 15 KHz that is frequency modulated on the carrier, i.e. a signal with a +/-
75 kHz maximum deviation from the center frequency. This leaves 25 kHz upper and lower
"guard bands" to minimize interaction with an adjacent frequency band. Hence, the
distance between FM radio programs is normally about 200 kHz. The base band signal
may also contain a S-signal for stereo. This is modulated on a suppressed carrier
of 38 KHz and inserted in the base band signal. Finally a pilot tone of 19 KHz, for
synchronization, and a RDS signal also on a suppressed carrier at 57 KHz, may be inserted
in the base band. See fig. 2.
[0115] Fig. 2 illustrates a diagrammatic representation of a FM base band signal. As can
be seen from fig. 2, the base band signal may comprise the following:
- A: A Main Channel Mono signal (left+ right audio channel) in the range of 30 Hz to
15 kHz. This part is also known as the M-signal.
- B: A predefined pilot tone of 19 kHz.
- C: A Sub-channel difference signal (left - right) in the range of 23 kHz to 52 kHz.
This part is also known as the Stereo signal or S-signal. This part is located at/around
a suppressed 38 kHz sub-carrier being a 2nd harmonic of the 19 kHz pilot tone B.
- D: A 57±2.5 kHz Radio Data System signal. This signal is located at a 57 kHz sub-carrier
(3rd harmonic of the 19 kHz pilot tone).
[0116] In the following different embodiments of establishing the interception signal 4
is described in relation to establishing the carrier of the interception signal:
The modulation index "m" indicates by how much a modulated frequency varies around
its un-modulated frequency, such as a carrier wave. The modulation index is given
by the following equation:

where m is the modulation index, fd is the frequency deviation and fm is the modulation
frequency. For example, the highest modulation frequency in mono audio broadcasting
is 15 KHz, resulting in a modulation index m= 75/15= 5.
[0117] It is to be noted that the size of m for FM indicates the signal's ability to withstand
noise and interference. Typical the interference resistance for a FM signal is proportional
to m, compared to AM (amplitude modulation). A small m, as for the RDS signal as calculated
in the following, indicates that the RDS signals are highly sensitive/ susceptible
to interference.
[0118] The carrier wave for the RDS- or RBDS information is located as a narrow-band FM
signal at a suppressed sub-carrier at 3 times the predefined pilot tone of 19 kHz,
i.e. a 57 kHz subcarrier as seen in fig. 2. The frequency deviation Fd
RDS of the RDS signal is predefined to be e.g. ±2.5 kHZ. Given the above, the modulation
index of the RDS as seen in the base band for the 57 KHz subcarrier, is:

[0119] On the carrier, the level after demodulation for the 57 KHz composite RDS signal
is about -40 dB compared to max +/- 75 KHz for FM carrier thus being 75KHz/100= 0,75
KHz. Giving M (rds)= 0,75/57= 0,0132.
[0120] The above calculations indicate that the RDS information is a very narrow band FM
signal. Hence, even weak radio signals in the sidebands + and - 57 KHz added to or
interfering with a carrier can severely harm the RDS reception due to the very low
modulation index of the RDS signal.
[0121] A signal containing only the two RDS sidebands will thus be able to interfere with
the RDS reception without disturbing the Mono- audio and S-stereo signals of the received
FM program, if omitting transmitting or by at least reducing a carrier and signals
in the base band of the interception signals equivalent S-band (23kHz to 52kHz) and/or
M-band (30 Hz to 15 kHz.) as illustrated in fig. 2.
[0122] Given the above, a signal may be generated, containing only the equivalent around
the 57 KHz RDS sidebands, but the carrier itself may be suppressed by using some facts
of FM modulation:
A t certain levels of modulation where the modulation index is e.g. about for example
2.41, it appears that the carrier of a signal falls substantially to a figure of zero,
so that the signal is substantially being comprised by the sidebands. Hence, by adjusting
the frequency deviation of the carrier wave fc to obtain a modulation index of for
example 2.41, this will substantially remove the carrier wave from the composite signal.
Such a signal hence being able to "intercept" only the RDS signal from e.g. a broadcasting
station.
[0123] The adjustment of the modulation index to a desired value may be performed by adjusting
the frequency deviation due to the following equation:

[0124] Hence, to achieve a modulation index of 2.41 for 57 KHz, on a carrier signal at for
example 100 MHz, the frequency deviation fd should be about:

[0125] In this case severe side bands are generated in the neighbor channels, so proper
filtering removing anything outside +/- 75 KHz is preferred.
[0126] Also, in embodiments, it is to be preferred that a filtering is performed during
establishing of the interception signal 4, where the filter arrangement comprises
a characteristic that allows signals in the RDS band of the interception signal to
be transmitted from the warning arrangement 10 and then be received and processed
by receivers 3 while signals at frequencies in the S-band and/or M-band of the interception
signal 4 are damped at least 10 dB such as at least 20dB, for example at least 40dB.
[0127] This may be achieved with e.g. a proper designed band pass filter e.g. as described
in more details later on in this document. Hence, establishing an interception radio
signal 4 based on a carrier wave 20 (see fig. 3), where the modulation index is e.g.
about 2.41, and modulating this carrier signal 20 with a signal at the RDS frequency
band (57kHz±2.5kHz) (or ±3.0 kHz) would provide advantages in relation to the power
needed to manipulate the RDS facility of radio receivers 3 if interception was conducted
on the carrier itself. The reason for this is that such a signal would look substantially
as illustrated in fig. 3 where the carrier 20 of the interception signal 4 is significantly
reduced or even close to zero. The interception signal 4 hence contains energy in
the equivalent 57 KHz RDS sidebands, while the energy at the carrier 20 is substantially
zero or at least significantly reduced.
[0128] At certain other values of a modulation index such as e.g. substantially around 5.53,
8.65 and further higher specific levels of the modulation index that may be identified,
the carrier will also fall substantially to zero or at least be significantly reduced,
and hence the same as described above may be obtained by adjusting the frequency deviation
and thereby the modulation index.
[0129] The amount of energy at the carrier frequency 20 compared to other frequencies in
the signal 4 is dependent on the selected modulation index as explained above. By
studying the Bessel function, further advantageous values of the modulation index
may be identified to obtain a reduced carrier. For example, in embodiments of the
invention, the modulation index may be preselected to a value between 1.8-3.0, between
5.0-6.0, or between 8.0-9.0. In an embodiment of the invention, a modulation index
may be selected so that the amplitude of the carrier 20 is reduced to being less than
50% such as less that 35% for example less that 25% such as less than 10% compared
to the un-modulated carrier (i.e. a modulation index of zero) by adjusting the frequency
deviation. However, in embodiments of the invention, de modulation index may be selected
so that the carrier is substantially zero and so that the interception signal 4 substantially
only comprise energy in the RDS side-bands 21a, 21b as seen in fig. 3. Also, it is
to be understood that in embodiments of the invention, the modulation index may be
selected to a value where the amplitude of the carrier is not zero, but is reduced
compared the un-modulated level of the carrier.
[0130] As mentioned both above and later on, the establishing of the interception signal
4 is preferably followed up by a suitable filtering to keep the interception signal
inside the boundaries of the FM channel to be intercepted and not disturbing neighbor
channels. Such a filtering may comprise a kind of bandpass filtering, e.g. by a filter
arrangement having a substantially 200 kHz bandwidth or any other suitable bandwidth
and having suitable cut-off frequencies.
[0131] It is to be understood that in fig. 3, the reference 21a refer to the RDS signal
in the lower sideband of the interception signal 4, i.e. the carrier 20 - 57 kHz,
whereas the reference 21b refer to the RDS signal in the upper sideband of the interception
signal 20, i.e. the carrier 20 + 57 kHz.
[0132] The reference 22a refers to the -2.5 kHz of the lower RDS sideband 21 a, whereas
the reference 23a refers to the +2.5 kHz of the lower RDS sideband 21a. In the same
way, the reference 22b refers to the -2.5 kHz of the upper RDS sideband 21b, whereas
the reference 23b refer to the +2.5 kHz of the upper RDS sideband 21 a. Hence, the
lower sideband 21a constitutes a -57+2.5 kHz signal and the upper sideband 21b constitutes
a +57±2.5 kHz signal compared to the carrier 20.
[0133] In general, it is to be understood that in some countries/regions, a substantially
±3 kHz frequency deviation of the RDS signal may be used instead of the ±2.5 kHz as
indicated earlier. In such countries the interception signal may be adapted accordingly.
[0134] In fig. 3, the parts of the interception signal are illustrated as the radiated power
as a function of the frequencies of the interception signal.
[0135] Another way of establishing the interception radio signal may comprise establishing
two signals at different carrier frequencies, being the carrier to be intercepted
minus 57 KHz for the one and +57 KHz for the other, where the two signals has a substantially
90° mutual phase shift,. Hence, combining these two signals would result in an interception
radio signal where the carrier is substantially reduced or even substantially zero,
while the + and -57 kHz signals is substantially maintained in the side bands of the
two carries. Thus the signal established hereby may intercept the signal from the
external broadcasting arrangement exactly in the sidebands where the original RDS
information of the radio signal from the external broadcasting arrangement is located,
whereas the carrier would be reduced or substantially zero.
[0136] A further way of establishing the interception radio signal may comprise establishing
it by digital means such as comprising a digital synthesiser or signal processor arrangement
being manipulated to establish a signal mainly or solely comprising energy at the
RDS frequency range, i.e. being the carrier to be intercepted +/-57kHz±2.5 kHz (the
latter being the RDS modulation content).
[0137] Common to the different ways of establishing the interception signal 4, e.g. as described
above is preferably that the interception signal 4 may be established based on a carrier,
where the energy at the carrier frequency 20 when the interception signal 4 is broadcasted
is significantly reduced.
[0138] Now, turning to the content of the signal in the RDS sideband of the interception
signal 4, the RDS sidebands 21a may comprise different types of information to manipulate
the RDS radio receivers 3 to automatically tune the radio receivers 3 to the channel
of the traffic bulletin signal 2.
[0139] Utilizing the RDS facility of the radio receivers 3 to automatically tune the radio
receivers 3 to the channel of the traffic bulletin signal 2 may be done in various
ways as described in the following.
[0140] In the following, some features of the RDS system is described in more details. The
RDS system among other provides a traffic service. This service is facilitated by
an Enhanced Other Networks (EON) feature in the RDS system, also referred to as EON
feature in the following. The EON feature is designed to allow the RDS system to become
"intelligent". The basic function of EON, is to build up a database of information
about other transmissions and, if appropriate, to place it into a database in a memory
of receivers 3. The EON feature defines a relation between associated radio programs,
and allows a receiver to monitor other radio programs for traffic programs, and automatically
temporarily tune into that station.
[0141] EON radio programs transmit a Traffic Program flag TP, also referred to at TP flag
in the following. The TP flag identifies programmes that, from time to time, carry
messages addressed to motorists. Such messages are e.g. traffic announcements in a
transmitter network. The receiver 3 uses this information to identify a radio program
that transmits traffic announcements. If the TP flag is set, the program is used for
transmitting traffic announcements.
[0142] EON radio programs may furthermore transmit a Traffic Announcement flag TA also referred
to as TA flag in the following. The TA flag is an indicator for a currently active
traffic announcement. The receiver 3 of a vehicle 1 can act in different ways when
receiving this information. If the receiver 3 is tuned to a traffic program P4 and
receives the TA information it usually turns up the volume until the traffic announcement
is over. If the receiver is not tuned to a traffic program, the receiver switches
to the program until the traffic announcement is over.
[0143] Table 1 below indicates status of traffic announcement features of the RDS system
dependent on the status of the TP flag and the TA flag.
Table 1
TP |
TA |
Meaning |
0 |
0 |
No traffic service possible at all on or via this service |
0 |
1 |
Traffic service provided via one or more EON cross-referenced services |
1 |
0 |
Traffic service provided on this service and also possibly via EON services |
1 |
1 |
Traffic report in progress on this service |
[0144] An EON radio program also transmits a Program Identification code PI, also referred
to as PI code in the following. The PI code is a 16-bit code comprising a country
symbol, a regional code, and a number permitting the identification of the broadcaster
and the particular programme, and may thus be regarded as a unique identifier for
a radio program. PI codes are assigned in such a way that receivers automatically
can tune to other transmitters radiating the same program by identifying the same
Programme Identification Code, that is, all 16 bits should be identical. It is to
be understood that PI codes given in this document are only examples, and that any
other suitable PI codes may be utilized.
[0145] RDS Radio receivers furthermore often comprises an AF (Alternate frequency) lists
to facilitate automatic tuning of an RDS receiver 3 to the same radio program at different
predefined channels/frequencies when the first signal becomes too weak. The AF list
thus indicates carrier frequencies on which a specified service is broadcasted. AF
lists may be broadcasted for a tuned service and also for other services using the
EON feature. The receivers 3 may ascertain the suitability of each frequency in the
AF list by evaluating the signal quality and decoding the PI code to check that there
is an exact match before switching frequencies automatically.
[0146] It is to be noted that the RDS system utilizes data groups to transmit data relating
to among other things the traffic announcement feature facilitated by the RDS system.
Such data groups includes among others data group types 14A and 14B of the RDS system
which are utilized in relation to the traffic announcement feature facilitated by
the RDS system and comprise EON information. AF lists for cross-referenced services
are normally carried in type 14A groups. Type 14A groups also comprise information
about TP flags of cross-referenced services.
[0147] The type 14B groups preferably also carries information about TA flags for cross-referenced
services. Type 14B groups may be transmitted only when there is a change in status
of the TA flag of a referenced service, it may be transmitted continuously with a
predetermined interval to facilitate appropriate information sharing with receivers
and/or the like. Furthermore, type 14B groups may comprise a particular PI code for
identifying a program facilitating transmitting traffic announcements. This received
PI code is preferably previously stored in memory of the receiver 3. If the PI code
is memorised in the receiver, then associated alternative frequencies (AFs) may also
already have been noted for particular signal strength/quality.
[0148] Embodiments of a process of transmitting the interception signal 4 and a traffic
bulleting signal 2 is described in relation to fig. 4.
[0149] At step S41, The warning arrangement 10 is set to broadcast the traffic bulletin
signal 2 (referred to as TBS in fig. 4). The traffic bulletin signal 2 may in embodiments
of the invention comprise one or more of the following information:
● A TP flag set to one to enable that radio receivers consider the signal as a traffic
service radio program,
● A TA flag is set to one to ensure that receivers within range of the traffic bulletin
signal and tuned to receive the signal remain to be tuned to the traffic bulletin
signal.
● A PI code of the traffic bulletin signal.
[0150] The TA flag of the bulletin signal 2 may in embodiments be toggled between 1 and
0, e.g. with a predetermined interval, to facilitate the receivers 3 tuned to and
receiving the traffic bulletin signal 2, are allowed to return to a previous program
to which they were tuned before being spoofed to tune to the traffic bulletin signal
by embodiments of the invention. Alternatively, the TA flag may be kept at a value
of 1 and the radio receivers may automatically retune to a previous radio channel
to which they were tuned before tuning/shifting to the traffic bulletin signal when
being out of range of the traffic bulletin signal and/or the interception signal,
because the emergency vehicle 11, or the vehicle 1, has moved away and thus no longer
covers the receiver. Also the TP flag of the traffic bulletin signal 2 may be toggled
in embodiments of the invention and/or may be kept at "1".
[0151] The PI code of the traffic bulletin signal 2 may be identical to all traffic bulletin
devices of the system so that all warning arrangements 10 transmit the same PI code.
Alternatively, the system 1 may comprise one or more warning arrangements 10 assigned
with different PI codes e.g. dependent on a priority, type of emergency vehicle and/or
the like. Also, in embodiments, a warning arrangement 10 adapted to be located at
a stationary geographical location near roadwork- or emergency locations or the like
may be assigned to a lower priority than warning arrangements 10 located in emergency
vehicles 11. In embodiments, the PI codes may be the same for a group of warning arrangements
while another group comprises another PI code. Thus, the warning arrangement 11 signalizes
a traffic program in the form of the traffic bulletin signal 2, and the TA flag of
the traffic bulletin signal, if set to one, results in the warning arrangement 11
signalizing an active traffic message.
[0152] A broadcasting channel for transmitting the traffic bulletin signal 2 is selected
and the traffic bulletin signal 2 (TBS in fig. 4) is broadcasted at the channel. The
selection of a channel for transmitting the traffic bulletin signal 2 may be selected
in various ways.
[0153] In an embodiment of the invention, the channel of the traffic bulletin signal 2 may
be kept substantially fixed at a predefined channel. Alternatively, the channel of
the traffic bulletin signal 2 may be varied based on a look up table and a positioning
system such as a GPS (Global Positioning System), a cell phone system determining
the position based on triangulation and/or any other suitable positioning system facilitating
determining the position of the warning arrangement 10. Hence based on e.g. the determined
position coordinates of the warning arrangement 10, a lookup table comprising channel
information (e.g. PI codes, frequencies and/or the like) and coordinates or other
position information specifying which channel that should be utilized in a specific
area may be processed to determining a suitable radio channel for the traffic bulletin
signal at the specific area that the warning arrangement is located.
[0154] In a further embodiment, the warning arrangement 10 may receive the channel for the
traffic bulletin signal 2 from an external source such as an external broadcasting
arrangement 6, a central handling arrangement handling and monitoring a plurality
of warning arrangements and/or the like. Also, in embodiments the warning arrangement
10 may determine the channel for transmitting a traffic bulletin signal 2 by having
a FM scanning arrangement scanning the FM band for a free channel for transmittance
of the traffic bulletin signal. The scanning may e.g. comprise the scanning arrangement
determining if any audio information configured for being transmitted to a listener
is present in the M-band and/or S-band of a plurality of FM channel frequencies.
[0155] Also, in the event of scanning FM channels so as to identify a suitable channel for
broadcasting the traffic bulletin signal, RDS information of the scanned frequencies
may also be processed, e.g. to determine pointers to radio channels configured for
transmitting traffic announcements.
[0156] An audio signal in the form of e.g. a siren audio signal, a prerecorded audio message,
an audio signal detected by a microphone and/or the like as explained earlier is added,
e.g. by modulation, to the selected channel in the S-band and/or M-band of the transmitted
traffic bulletin signal.
[0157] In step S42, the Traffic bulletin signal established in Step S41 is broadcasted with
a signal strength so that receivers 3 of nearby vehicles 1 will receive and broadcast
the above mentioned audio content/signal of the traffic bulletin signal 2 when tuned
to the radio channel of the traffic bulletin signal 2.
[0158] In step S43, the interception signal 4 is established (referred to as ICS in fig.
4). The establishment of the traffic bulletin signal 4 may be performed in different
ways which are explained in more details later on in relation to e.g. figs. 5-7 as
well as above in relation to e.g. fig. 2 and 3.
[0159] One or more channels for transmitting the interception signal 4 is/are selected.
The selection of channels for broadcasting the interception signal 4 may be selected
in different ways. For example, the warning arrangement 10 may correlate position
information obtained by a positioning system, e.g. as explained above, with a lookup
table to determine the channel for transmittance of the interruption signal(s) 4.
In another embodiment, a scanning arrangement may be configured for continuously scanning
FM radio channels in the FM band for selecting the channel(s) suitable for broadcasting
the interception signal 4. In e.g. this embodiment, RDS information of radio signals
from external broadcasting stations may also be processed to e.g. identify the program
transmitted on the channel from an external processing arrangement 6, to identify
relevant frequencies/channels in AF lists and/or the like.
[0160] The process of determining broadcasting channels for the traffic bulletin signal
2 and/or the interception signal(s) 4 may be performed continuously over time. This
may be especially relevant in embodiments where the warning arrangement 10 is placed
in an emergency vehicle 11, in that emergency vehicles often may move over a larger
geographical area. Since the channels on which e.g. local commercial radio stations
transmits their radio programs changes dependent of the geographical area, the channel
of the interception signal(s) 4 and/or the traffic bulletin signal 2 may need to be
adapted to the position/location of the emergency vehicle 11 so that receivers 3 of
vehicles 1 originally tuned to e.g. the channels of the commercial radio stations
are manipulated to automatically tune to the traffic bulletin signal 2 from the warning
arrangement by means of the interception signal.
[0161] In embodiments where the warning arrangement 10 is configured for being temporarily
and/or substantially permanently arranged near a road to warn drivers of approaching
vehicles 1, the warning arrangement 10 may be manually and/or automatically set to
a predefined radio broadcasting channel for the traffic bulletin signal 2 and one
or more radio broadcasting channels for broadcasting the interception signals 4.
[0162] In step S44, the interception signal established in Step S43 is broadcasted with
a signal strength so that receivers 3 of nearby vehicles 1 will receive and process
the content of the information in the RDS band of the interception signal.
[0163] The signal strength of the interception signal 4 may be determined and e.g. varied
in different ways. In an embodiment of the invention, the signal strength of the interception
signal may be preselected to a substantially fixed value. In other embodiments of
the invention, the warning arrangement 10 may comprise a scanning arrangement configured
for detecting the signal strength of signals from external broadcasting arrangements
6 at the location of the warning arrangement 10 at relevant channels for transmittance
of the interception signal 6. Hence, the signal strength of the interception signal
may adapted/regulated (preferably automatically by the warning arrangement) based
on such determined signal strengths of radio signals from external broadcasting stations
to insure that the interception signal is on the one hand strong enough to ensure
that nearby receivers derive the RDS information hereof and on the other hand to prevent
that vehicles/receivers located at a longer distances away from the warning arrangement
does not derive the RDS information.
[0164] Also, in embodiments of the invention, the signal strength of the interception signal
may be determined based on a positioning system and a look up table comprising a plurality
of predetermined signal strengths to be utilized dependent on the location of the
warning arrangement 10.
[0165] In general it is to be understood that in embodiments of the invention, the signal
strength of the interception signal and/or the traffic bulletin signal may be adapted
based on the local radio broadcasting environment for a given geographical area. The
reason for this is that since the interception signal may be arranged for substituting
RDS information broadcasted from external broadcasting arrangements with its own Information
in the RDS band. Hence, the signal strength in the RDS band of the interception signal
4 may advantageously be varied to intercept the RDS band of a radio channel, and the
criteria for this being successfully achieved would depend on that the energy in the
RDS band of the interception signal being higher than the energy in the RDS band of
the signal 5 from an external broadcasting station 6.
[0166] Different ways of manipulating the receivers 3 to automatically tune to the traffic
bulletin signal 2 by means of the information in the RDS band of the interception
signal 4 is explained in the following.
[0167] If a signal becomes too weak, radio receivers 3 comprising the Radio Data System
facility may be adapted to tune to another channel. In the following, a method of
initiating such a tuning by the interception signal 4 comprising a disturbance signal
in the RDS band is described. A first indicator of a radio signal becoming too weak
may be identified in the RDS sideband of a radio signal from an external broadcasting
station 6 due to the very low modulation index of the RDS signal as calculated earlier.
Hence, many radio receivers 3 are predetermined to seek in the AF list if the RDS
signal of the signal from the external broadcasting station becomes too weak/interrupted.
Based on this, in an embodiment of the invention, the information in the RDS sideband
of the interception radio signal 4 transmitted from the warning arrangement 10 may
comprise a noise signal modulated onto the 57±2.5kHz (and/or ±3kHz) sidebands of the
interception signal. The noise signal may e.g. comprise white noise, it may comprise
grey noise and/or any other suitable signal that does not necessarily comprise RDS
information but may disturb the RDS information in the signal 5 transmitted from an
external broadcasting station 6. Hence, when the radio receivers 3 receives/registers
this noise at the RDS side bands, the receivers 3 interpret this as the radio signal
5 from the external broadcaster 6 getting weak/interrupted and would hence automatically
start to seek in the AF list for an alternate frequency to tune to. This process is
described in more details in relation to fig. 5.
[0168] In step S51, one or more external broadcasting arrangements transmits RDS information
at one or more predefined channels P2 that would have receivers 3 receiving and processing
this RDS information to tune to the traffic bulletin signal 2 when they register a
bad RDS signal This RDS information is preferably transmitted together with an audio
signal of a radio station such as a commercial radio station. This RDS information
may comprise channel information, comprising information of the channel frequency
P1 of the traffic bulletin signal 2. Furthermore, the RDS information may in embodiments
comprise the PI code PI2 of the traffic bulletin signal 2. Also, the RDS information
may comprise information in the form of the TP flag identifying the traffic announcement
channel as a channel for transmitting channel information.
[0169] This RDS information is received, registered and stored in the receivers 3 in step
S52. Preferably, the PI code and the channel frequency of the traffic bulletin signal
2 is transmitted by the external broadcasting station 6 in a way so that the when
the receivers starts looking for a new channel due to a weak/interrupted RDS signal
at the channel to which the receivers are tuned, the channel P1 of the traffic bulletin
signal is among the first, if not the first to be looked for. This may be achieved
by adapting and transmitting the RDS information in a way so that that it will be
stored in the AF list as one or the first channels to be looked for.
[0170] In step S53, the warning arrangement 10 selects a channel for transmittance of the
interception signal 4, in this case e.g. P2 at which the external broadcasting arrangement
transmits a radio program and to which one or more receivers 3 are tuned.
[0171] At step S54, a noise signal is added to the interception signal in the RDS range,
preferably followed up by a proper filtering so that the noise only is present within
the RDS 57±2.5 kHz or (3.0 kHz) RDS range, to avoid disturbing e.g. audio signals
in the M-band and/or S-band as illustrated in fig. 2.
[0172] In step S55, the interception signal 4 is transmitted from the warning arrangement
10, and in step S56, the interception signal 4 is received by nearby receivers 3 at
the channel P2. The receivers 3 would now register the noise in the RDS band of the
interception signal at the channel P2, but the audio signal from the external broadcaster
at the channel P2 would not be disturbed due to that the interception signal 4 do
not contain any detectable audio signal in the S-band and/or the M-band that would
disturb the audio signal from the external broadcasting arrangement 6 from being broadcasted
by the receiver 3. The receiver 3 may however, due to the noise in the RDS band of
the interception signal 4, act as if the signal from the external broadcaster 6 is
getting weak/disturbed, and may thus initiate seeking for an alternate frequency in
e.g. the AF list.
[0173] Here is to be remembered that an external broadcasting arrangement in step S 1 has
specified the channel P1 of the traffic bulletin signal 4 as being an acceptable alternate/alternative
frequency, and the PI code PI2 of the traffic bulletin signal. Hence, the receivers
3 may automatically at Step S57 seek for the traffic bulletin signal 2 at channel
P1, which would be present due to that the traffic bulletin signal is transmitted
from the warning arrangement 10, preferably simultaneous to the transmittance of the
interception signal 4.
[0174] In embodiments of the invention, the traffic bulletin signal 2 at channel P1 may
comprise a PI code that is identical to the PI code of the radio program that the
receiver was tuned to before shifting to the channel of the traffic bulletin signal.
Hence, the radio receiver would see the traffic bulletin signal as a radio program
that comprises the same audio signal as the radio signal that the receiver previously
received.
[0175] The warning arrangement may in embodiments be adapted for transmitting a plurality
of traffic bulletin signals comprising different PI codes that are identical to the
PI code of the radio program that the receivers was tuned to before shifting to the
traffic bulletin signal due to the information such as the noise signal in the RDS
band of the interception signal. This may for example be facilitated by the warning
arrangement comprising an arrangement adapted for scanning radio channels to identify
the relevant PI code to add to the traffic bulletin signal(s) dependent on the radio
program broadcasted at the channel that the warning arrangement is adapted to use
for transmitting the interception signal. This may e.g. be performed together with
identifying relevant channels for transmitting the interception signal as described
in embodiments in this document, and/or by means of a look up table that may e.g.
furthermore be dependent of the geographical location of the warning arrangement and/or
any other suitable means.
[0176] In embodiments where a plurality of traffic bulletin signals are transmitted comprising
different PI codes, the signals may be transmitted simultaneously at different channels,
they may be transmitted shift wise where the PI code and the channel for transmittance
may be varied, and/or the like.
[0177] Hence, the receivers may at test TE51 if an acceptable radio signal is present at
the channel P1 of the traffic bulletin channel, and it is in general understood that
the warning arrangement 10 may be adapted so as to transmit a traffic bulletin signal
2 with a suitable strength and quality so that receivers tuned to the traffic bulletin
signal 2 due to receipt of the interception signal would consider the traffic bulletin
signal as an acceptable radio signal.
[0178] At test TE52, the receivers 3 perform a test to validate the PI code PI2 of the traffic
bulletin signal. This will also be accepted due the external broadcasting arrangement
6 having identified the PI code PI2 of the traffic bulletin signal. Hence, the receivers
3 starts broadcasting the audio signal of the traffic bulletin signal at step S58.
[0179] When a predetermined return condition is applied with (test TE53), the receivers
3 may return to and broadcast the radio program of the previous channel (S59). The
return may be performed in various ways. For example, if either the warning arrangement
10 is arranged in an emergency vehicle 11, or is arranged stationary, the receivers
may automatically be arranged to tune to the previous station when the vehicles gets
out of range of the traffic bulletin signal and/or the interception signal due to
the vehicles driving in a direction away from the warning arrangement and/or the emergency
vehicle 11 moving away from the vehicles receiving the traffic bulletin signal 2.
Hence, the receivers may look in the AF list again and thus tune to the previous channel
P2 since the traffic bulletin signal is no longer within range.
[0180] Also, in embodiments, the traffic bulletin signal may comprise RDS information initiating
the receivers to tune to the previous station. E.g. by manipulating a TA flag and/or
a TP flag of the traffic bulletin signal so that a RDS receiver 3 would consider the
channel as a channel transmitting traffic announcements. Hence, by toggling the TA
flag and/or TP flag, e.g. with a time dependent interval, the receivers may return
to the previous channel. The reason for this is that RDS receivers 3, when registering
that e.g. the TA flag is not set, may return to the previous channel.
[0181] Furthermore, in embodiments, this may e.g. be combined with the interception signal
4 being stopped or manipulated in a way so that the receivers would not try to tune
to the traffic bulletin signal again for a predetermined amount of time.
[0182] The RDS information of the traffic bulletin signal may also in embodiments of the
invention comprise information to be stored in the AF list of the receivers, and relating
to which channel to return to. This may be determined by means of a look up table,
e.g. combined with a positioning system as explained later on and dependent on the
selected channel P2 for the interception signal. Here is to be understood that by
knowing the channel P2 of the interception signal, valid channels to be returned to
may be identified by e.g. a lookup table, which would eventually result in the receivers
3 tuning to a radio program that was received by the receiver before the receiver
was shifted to the traffic bulletin signal.
[0183] Another way of manipulating RDS radio receivers of vehicles 1 to automatically tune
to the traffic bulletin signal 2 may be adapting the interception signal 4 to comprise
RD S information that would have the receivers 3 tuning to the traffic bulletin signal.
Such an embodiment is described in the following in relation to fig. 6.
[0184] At Step S61, the warning arrangement 10 selects one or more radio channel(s) P2 for
transmitting the interception signal 4. The selected channel P2 is preferably identical
to the channel at which one or more external broadcasting arrangements 6 broadcast
radio programs that the receivers 3 may be tuned to. The selection of a radio channel
may for example be performed as explained in relation to fig. 4.
[0185] At step S62, RDS information comprising RDS data is added to the RDS band of the
interception signal 4. The added RDS information is preferably adapted so as to utilize
the EON feature of the RDS system to have the receivers 3 tune to the traffic bulletin
signal 2. The RDS information of the interception signal may in embodiments comprise
an identification of the broadcast channel P1 of the traffic bulletin signal to e.g.
be implemented in an Alternative Frequency list of the radio receivers. The RDS information
of the interception signal 4 may also in embodiments comprise a RDS program identification
code PI2 identical to a RDS program identification code PI2 of the traffic bulletin
signal 2. Also, the RDS information of the interception signal 4 may comprise a TA
flag indicating a currently active traffic announcement at the channel P1 of the traffic
bulletin signal 2. Likewise, the RDS information of the interception signal 4 may
in embodiments comprise a TP flag set so as to indicate that the channel of the traffic
bulletin signal 2 may transmit a RDS traffic announcement.
[0186] At step S63, the interception signal (ICS) is broadcasted at the channel P2 from
the warning arrangement and comprising the RDS information. This signal 4 is received
by nearby radio receivers 3 in step 64. The receivers 3 would now register the RDS
information in the RDS band of the interception signal 4 at the channel P2, but the
audio signal from the external broadcaster at the channel P2 would not be disturbed
due to that the interception signal 4 do not contain any detectable audio signal in
the S-band and/or the M-band that would disturb the audio signal from the external
broadcaster 6. The receivers 3 may however, due to the RDS information in the RDS
band of the interception signal 4 act as if the signal from the external broadcaster
6 is transmitting the information that a traffic announcement is present at the channel
of the traffic bulletin signal, e.g. due to a TA flag set to "1" in the RDS information
of the RDS information of the interception signal 4.
[0187] Hence, the radio receiver 3 at step S65 starts to seek for a channel transmitting
the indicated traffic announcement. This channel may e.g. be identified in an AF list
that has been modified by the RDS information of the interception signal to comprise
the channel information and PI code PI2 of the traffic announcement signal 2.
[0188] If the receiver 3 detects a signal 2 (test TE61) from the warning arrangement 10
at the tuned channel P1, the receiver 3 proceeds at the channel P1 to receive the
radio signal 2, if not, it may return to the previous program at step S67.
[0189] The receiver 3 at test TE62, when tuned to the frequency P1 of the traffic bulletin
signal 2, may determine if a TP flag is set to one in the RDS information of the traffic
bulletin signal 2. If the TP flag it is set to one, the receiver 3 proceeds, otherwise
it may return to the previous program (step S67).
[0190] Also, the receiver 3 may furthermore at test TE63 check if the PI code PI2 of the
traffic bulletin signal 2 is identical to the PI code identified in the receiver 3
as being the PI code of a channel broadcasting traffic announcements. This may be
performed by comparing the PI code of the signal 2 with a stored PI code (which may
be stored in the receiver by the RDS information of the interception signal). If it
is identical to the PI code received in the interception signal 4, the receiver 3
proceeds, if not, it may return to the previous program at step S67.
[0191] If the PI code PI2 of the traffic bulletin signal 2 is accepted, the receiver at
step S66 may start receiving the traffic bulletin information in the form of the audio
signal added to the traffic bulletin signal as explained above, and/or by registering
a text in a display of the radio receiver 3 determined by a RDS PTY facility of the
RDS receiver. Also, the volume of the audio signal broadcasted by the receiver 3 may
be automatically increased, and/or, if e.g. a CD is listened to, the audio signal
of the CD may be temporarily interrupted to broadcast the audio signal of the traffic
bulletin signal 2.
[0192] At test TE64, the receiver 3 may continuously tests if the TA flag of the traffic
bulletin signal is set to 1, and if the receiver 5 registers that the TA flag is set
to zero this indicates that the traffic bulletin from the warning arrangement 10 is
over, and the receiver 3 returns to the previous station at step S67 regardless of
which PI code was used by the traffic bulletin signal. Also and/or alternatively,
in embodiments, the receiver 3 may automatically return to the previous channel when
the traffic bulletin signal becomes to week due to increased distance between the
vehicle 1 and the warning arrangement 10.
[0193] In embodiments, the interception signal 4 may comprise channel information to be
stored in receivers 3 receiving the RDS information of the interception signal 4,
and identifying which channel to return to after receipt and broadcast of a traffic
bulletin of the traffic bulletin signal. Alternatively, the interception signal may
be adapted to only manipulate the receiver so that the receiver registers the channel
information, PI information and TP flag information of the traffic bulletin signal
while other radio channels previously registered in an AF list of the receiver 3 are
remained.
[0194] Fig. 7 illustrates one embodiment comprising five radio programs providing the facility
of the RDS traffic service. The radio programs P5_1, P5_2 and P5_n are ordinary radio
programs with an EON feature, whereas P3 is registered to be an ordinary traffic program
facilitating broadcasting ordinary traffic announcements. This is illustrated by the
TP flag of P3 being set to 1 whereas the TP flag is set to 0 at P5_1, P5_2 and P5_n.
Each program P5_1, P5_5 and P5_n and P3 has its own PI code, i.e. the PI code of P2_1
= 100C, the PI code of P3= 100D, the PI code of P2_2 = 100E, and the PI code of P2_n
= 100F. It is understood that these PI codes are purely examples to enhance understanding.
[0195] Broadcasting arrangements 6 as the one described in relation to e.g. fig 1 in general
facilitate transmitting RDS data to receivers 3 to induce these to shift to the predefined
program P3 when an ordinary traffic announcement is broadcasted at P3.
[0196] To enable listeners listening to the programs P5_1, P5_2 and P5_n, to hear the traffic
announcement at P3, the broadcasting arrangement 2 transmits RDS data to the receivers
3 of vehicles 1 at each of the programs P5_1, P5_2 and P5_n comprising a TA flag set
to one and preferably also a PI code for the traffic program P3. This information
may e.g. be transmitted at the type 14B groups which may be transmitted when there
is a change in status of a TA flag.
[0197] Now, the traffic bulletin signal 2 broadcasted by the warning arrangement 10 of the
present invention may be identified as P1 in fig. 7. As illustrated, the traffic bulletin
signal may be broadcasted at a FM radio channel (e.g. 87.5 MHz as indicated but it
may be any suitable radio channel), it may have the TA flag set temporarily or continuously
to one, and furthermore, the TP flag may be set to 1 so that the receivers 3 would
also recognize the traffic bulletin signal 2 as a signal transmitting RDS traffic
announcements as the program P3 explained above.
[0198] The following example is explained in relation to figs. 7 and 8. To allow the warning
arrangement 10 to facilitate manipulating receivers 3 listening to e.g. the different
radio programs P5_1, P5_2 and P5_n at different channels to tune to the channel of
the traffic bulletin signal 2, the warning arrangement 10 may be configured to transmit
multiple interception signals 4_1 to 4_n at the channels of P5_1, P5_2 and P5_n. Hence,
different frequencies are identified as carriers for the interception signals 4, but
the information added to the interception signals in the RDS band of the interception
signals may be substantially similar. E.g. as described in relation to figs. 4, 5
and 6 above. This is illustrated in fig. 8. As indicated in fig. 8, the warning arrangement
may transmit a plurality of interception signals 4_1 to 4_n. Also, a plurality, of
broadcasting arrangements 6 may transmit radio programs at a plurality of different
radio channels 5_1 to 5_n. Therefore, to have receivers 3 of different vehicles 1
tuned to the different channels P5_1 to P5_n to tune to the channel of the traffic
announcement signal 2, the different interception signals 4_1 to 4_n are transmitted
at different channels corresponding to the different channels P5_1 to P5_n. For example,
the first interception signal 4_1 would be adapted to be transmitted at the channel
of the first radio program P5_1, the second interception signal 4_2 would be adapted
to be transmitted at the channel of the second radio program P5_2, and the "n" interception
signal 4_n would be adapted to be broadcasted at the "n" channel P5_n of the "n" radio
program.
[0199] Hence, the receivers 3 of the different vehicles 1 tuned to the different stations
may all be manipulated to tune to the same traffic bulletin signal 2 as described
earlier in this document.
[0200] In an embodiment, the interception signal(s) may be only transmitted at each broadcast
channel P5_1 to 5_n for so long time as to make receivers 3 to shift (tune) to receive
the traffic bulletin. This may be controlled by e.g. transmitting the interception
signal with a predetermined time interval, by transmitting the interception signal
with a time interval that varies according to the transmission power of the interception
signal or by any other suitable way.
[0201] Also, in embodiments, only the selected frequency of the interception signal may
be changed to transmit the interception signal at different channels as the RDS data
may be the same.
[0202] Fig. 9 illustrates a schematic view of an example of a warning arrangement 10. The
warning arrangement 10 comprises an interception signal arrangement 13. This arrangement
13 may comprise one or more analogue and/or digital electronic circuits adapted for
establishing the carrier of the interception signal at the selected channel. Furthermore,
the interception signal arrangement 13 may comprise an RDS arrangement 13a adapted
for establishing and adding information to the RDS band of the interception signal
4, e.g. as described earlier. The interception signal arrangement 13 may be connected
to an antenna arrangement 14 for transmitting the interception signal(s) 4. It is
understood that the interception signal arrangement 13 and the antenna arrangement
14 in embodiments may be adapted to facilitate transmitting one or more interception
signals. In the event that multiple interception signals are to be broadcasted at
different frequencies/channels, e.g. as described in relation to figs. 7 and 8, the
interception signal arrangement 13 and/or the antenna arrangement 14 may be adapted
to transmit such interception signals shiftwise one at the time after each other and/or
simultaneously e.g. as described above.
[0203] The interception signal arrangement 13 may furthermore comprise a filter arrangement
13b for adapting the interception signal so as to reduce energy in the S-band and/or
M-band of the broadcasted interception signal 4. The filter arrangement may comprise
any suitable analog and/or digital filter means. Also, the filter arrangement 13b
may comprise a band-pass filter, a high-pass filter and/or the like. An example of
a band-pass filter may be a filter with a center frequency of 57 kHz and a bandwidth
B
3dB of 2.5 kHz or 3kHz dependent of the RDS configuration.
[0204] The filter arrangement 13b may for example be adapted so that the information established
by the RDS arrangement 13a is processed by the filter arrangement 13b to damp energy
at frequencies in the S-band and/or M-band of the transmitted interception signal,
e.g. to obtain an interception signal 4 as illustrated in fig. 3.
[0205] The filter arrangement may be arranged to perform a filtering before the RDS part
of the interception signal is modulated/added to the carrier and/or after the RDS
part of the interception signal is modulated/added to the carrier.
[0206] The filter arrangement may furthermore comprise a filter that removes/ significantly
reduces anything outside +/- 75 KHz of the interception signal to comply with a FM
channel spacing of e.g. 200 kHz.
[0207] So it is to be understood that the filter arrangement 13b in embodiments may comprise
a filter arrangement for removing/reducing energy in the S- and/or M band of the interception
signal while keeping information in the RDS band of the interception signal, and/or
a filter arrangement for removing/reducing energy outside e.g. +/- 75 KHz of the interception
signal.
[0208] Also, the warning arrangement 10 comprises a traffic bulletin arrangement 15. This
arrangement 15 may comprise one or more analogue and/or digital electronic circuits
adapted for establishing the carrier of the traffic bulletin signal at the selected
channel. Furthermore, the traffic bulletin arrangement 15 may comprise a bulletin
arrangement 15a adapted for establishing and adding traffic bulletins to the of the
traffic bulletin signal, e.g. as described earlier. The traffic bulletin arrangement
15 may be connected to an antenna arrangement 16 for transmitting the traffic bulletin
signal 2.
[0209] It is in general to be understood that the warning arrangement may comprise a data
storage arrangement 12 for storing for example audio messages to be added to the traffic
bulletin signal 2. The data storage arrangement 12 may also comprise data such as
look up tables, channel information, a software program product adapted for having
the warning arrangement operate according to embodiments and/or combinations of embodiments
as described in this document. It is to be understood that the data storage arrangement
12 may comprise one or more data storages and that the data storages may be dedicated
to individual parts of the warning arrangement and/or may be shared between various
arrangements such as one or more of the arrangements 13, 13a, 15, 15a.
[0210] Also, the warning arrangement 10 may comprise a data processor arrangement 17 connected
to the data storage arrangement 12 comprising one or more data processors configured
for executing a program code so that the warning arrangement 10 is operating according
with one or more embodiments disclosed in this document, e.g. embodiments described
In relation to figs. 1-8 and/or as specified in the claims. It is understood that
the warning arrangement may in aspects comprise multiple data processors arranged
to carry out different processes according to aspects of the invention.
[0211] The warning arrangement 10 may furthermore in embodiments comprise a scanning arrangement
18 configured for detecting the signal strength of signals from external broadcasting
arrangements at the location of the warning arrangement 10 at relevant channels for
transmittance of the interception signal 6. This information may e.g. be utilized
by the interception signal arrangement 13 to determine and adapt the signal strength
of the interception signal(s) 4. The scanning arrangement may be connected to an antenna
19 so as to receive radio signals 5 from external broadcasting stations.
[0212] The transmissions of the interception signal(s) and/or traffic bulletin signal may
in embodiments be interrupted to be able to measure the field strength of the broadcast
program to be intercepted.
[0213] In embodiments, the warning arrangement 10 may comprise a channel scanning arrangement
24 configured for e.g. continuously determine a suitable channel for transmitting
a traffic bulletin signal 2, e.g. by scanning the FM band within the tuneable range
of receivers 3 for a free channel for transmittance of the traffic bulletin signal.
Also and/or the channel scanning arrangement 24 may be configured for continuously
scanning FM radio channels in the FM band for selecting the channel(s) suitable for
broadcasting the interception signal 4. This may be followed up by the warning arrangement
10 analysing RDS information in radio signals at different radio channels, e.g. compared
with a look up table or the like so as to e.g. identify relevant radio programs a
channel that would be suitable for being utilized for transmitting the interception
signal(s) and/or the traffic bulletin signal(s). The scanning arrangements 24 and
18 may in embodiments be the same arrangements, and/or it may be arrangements operating
substantially independent of each other. Likewise, the scanning arrangements 24 and
18 may as illustrated be adapted with couplers, combiners and/or filters for utilizing
the same antenna arrangement 19, or they may utilize different antenna arrangements.
[0214] The warning arrangement 10 may further more in embodiments comprise position determination
means (not illustrated) such as a position system as the Global Positioning System
(GPS) arrangement, a GSM (Global System for Mobile Communications) arrangement for
facilitating triangulation and/or any other suitable cellphone appliances or positioning
appliances that facilitates position determination and or the like. Also a TMC decoding
facility from the RDS signal of a broadcast station may be utilized to adjust to local
conditions like traffic jams and/or emergencies. Such a positioning system may be
implemented in various suitable ways in relation to e.g. determining suitable channels
for transmitting a traffic bulletin signal 2 and/or one or more interception signals,
in relation to determining the signal strength of a radio signal received from an
external broadcasting station 6 and/or the like.
[0215] It is generally to be understood that a warning system according to embodiments the
present invention may comprise one or multiple warning arrangements 10 according to
one or more embodiments of the invention as disclosed in relation to the claims and/or
the figures 1-9 and description of such figure(s).
[0216] Furthermore multiple methods as described in this document may be utilized for having
receivers 3 to be tuned to or to select a traffic bulletin signal 2. For example,
a warning arrangement 10 may be configured for simultaneously and/or alternatingly
(with e.g. a predefined interval) broadcasting interception signals (4, 4_1, 4_2,
4_n) according to the embodiments of adding noise or RDS data to the RDS band of the
interception signal as described in relation to figs. 4, 5 and/or 6.
[0217] Examples of the range(s) of the interception channel and/or traffic bulletin signal
may be no more than three kilometers, such as no more than no more than 1 kilometer
such as no more than 700 meters such as no more than 500 meters such as no more than
300 meters such as no more than 100 meters from the arrangement broadcasting the signal(s).
Hence within this distance from the warning arrangement, the signal(s) may be properly
received and processed as defined in this document.
[0218] In further embodiments, the interception signal(s) and/or the traffic bulletin signal(s)
may be directionally controlled, e.g. so as to achieve that more power of the signal(s)
is transmitted in a forward direction (e.g. in embodiments where the signals are transmitted
from an emergency vehicle) than to the sides and/or backwards in relation to the emergency
vehicle. For example the radiated power in a forward/rearward ratio may be 90/10 such
as 80/20 such as (70/30) such as 60/40), This may be achieved e.g. by a specific antenna
configuration facilitating such directional control of the radiated signals.
[0219] In general, it is to be understood that the present invention is not limited to the
particular examples described above but may be adapted in a multitude of varieties
within the scope of the invention as specified in the claims. For example, it is to
be understood that various combinations of the content of the interception signal(s),
the warning signals and the establishing of these may be varied within the scope of
the present invention. Also, it is understood that one or more steps as disclosed
in Figs. 5 and/or 6 in embodiments of the invention may be omitted, substituted with
another step, and/or the like. Also different steps of figs. 5 and 6 may be combined
into further embodiments.
1. A method of warning drivers of vehicles (1), said method comprising:
transmitting a traffic bulletin signal (2) at a first predefined radio channel (P1)
to one or more radio receivers (3) of said vehicles (1), which one or more radio receivers
(3) comprise a Radio Data System facility, and
transmitting at least one further radio signal being an interception radio signal
(4, 4_1, 4_2, 4_n), wherein said interception radio signal (4, 4_1, 4_2, 4_n) comprises
information (25) in the Radio Data System frequency range of a second radio channel
(P2) being different from the first radio channel (P1),
wherein said information is different from information in the Radio Data System frequency
range of a third radio signal (5) transmitted from an external broadcasting station
(6) at said second radio channel (P2), and
wherein said information is configured so as to manipulate said radio receivers (3)
to automatically tune said radio receivers (3) to said first radio channel (P2) to
receive said traffic bulletin signal (2).
2. Method according to claim 1, wherein said interception signal (4, 4_1, 4_2, 4_n) is
configured so that radio receivers without Radio Data System facilities and receiving
said interception signal continue to receive and broadcast an audio signal of said
third signal (5).
3. Method according to claim 1 or 2, wherein said information in the Radio Data System
frequency range of said interception signal (4, 4_1, 4_2, 4_n) is configured so that
radio receivers (3) with a Radio Data System Traffic Announcement facility disabled
and receiving said interception signal (4, 4_1, 4_2, 4_n) continue to receive and
broadcast an audio signal of said third signal (5) while other receivers (3) with
the Radio Data System Traffic Announcement facility enabled and receiving said interception
signal (4, 4_1, 4_2, 4_n) automatically tune to said first radio channel (P1) to receive
said traffic bulletin signal (2).
4. Method according to any of the preceding claims, wherein said information in the Radio
Data System frequency range of said interception signal (4, 4_1, 4_2, 4_n) is configured
so that radio receivers (3) with a Radio Data System AF facility disabled and receiving
said interception signal (4, 4_1, 4_2, 4_n) continue to receive and broadcast an audio
signal of said third signal (5), while other receivers (3) with a Radio Data System
AF enabled and receiving said interception signal (4, 4_1, 4_2, 4_n) automatically
tune to said first radio channel (P1) to receive said traffic bulletin signal (2).
5. Method according to any of the preceding claims, wherein said interception signal
(4, 4_1, 4_2, 4_n) is configured so that that the information of an audio signal of
said third signal (5) is derivable from the output of receivers arranged to continue
to receive and broadcast an audio signal of said third signal (5) while at the same
time receiving said interception signal (4, 4_1, 4_2, 4_n).
6. A method according to any of the preceding claims, wherein said interception signal
(4, 4_1, 4_2, 4_3) is adapted so that the energy of the carrier and eventual M-and
S- signals of said transmitted interception signal is reduced compared to the un-modulated
carrier.
7. A method according to any of the preceding claims, wherein a modulation index of said
interception signal targeting the RDS information is preselected to a value so that
the energy of a carrier of said transmitted interception signal (4, 4_1, 4_2, 4_3)
is reduced while the energy in the sidebands from the RDS information in the interception
signal is maintained.
8. A method according to any of the preceding claims, wherein a modulation index is selected
so that the energy of the carrier of the interception signal (4) is reduced to less
than 60% such as less that 35% for example less that 25% such as less than 10% compared
to the un-modulated carrier.
9. A method according to any of the preceding claims, wherein a filter arrangement (13b)
reduces and/or removes frequency components in the S-band and/or M-band of said interception
signal (4, 4_1, 4_2, 4_n).
10. A method according to any of the preceding claims, wherein said information of said
interception radio signal (4, 4_1, 4_2, 4_n) comprises a noise signal at said Radio
Data System frequency range, and
wherein one or more stationary broadcasting stations (6) transmits channel information
and/or a RDS Program Identification code (PI2) of said traffic bulletin signal (2)
to said radio receivers (3) so as to enable said receivers (3) to automatically tune
to said traffic bulletin signal (2) when receiving said interception radio signal
(4, 4_1, 4_2, 4_n).
11. A method according to any of the preceding claims, wherein said information (25) of
the interception radio signal (4, 4_1, 4_2, 4_n) comprises Radio Data System data.
12. A method according to any of the preceding claims, wherein said interception signal
(4, 4_1, 4_2, 4_n) comprises EON data configured so that receivers (3) with RDS traffic
announcement features in EON enabled will tune to said first predefined radio channel
(P1), and wherein receivers (3) with RDS traffic announcement features in EON disabled
will stay tuned to said second channel (P2).
13. A method according to any of claims 11-12, wherein said Radio Data System data comprises
an identification of the broadcast channel (P1) of said traffic bulletin signal (2)
to be implemented in an Alternative Frequency list of said radio receivers and/or
wherein said Radio Data System data comprises a program identification code (PI2)
of said traffic bulletin signal (2).
14. A method according to any of the preceding claims, wherein said traffic announcement
signal (4) and said interception signal (4, 4_1, 4_2, 4_n) are transmitted from an
emergency vehicle (11).
15. A warning arrangement (10) for warning drivers of vehicles (1), said warning arrangement
(10) being configured for:
transmitting a traffic bulletin signal (2) at a first predefined radio channel (P1)
to one or more radio receivers (3) of said vehicles (1), which one or more radio receivers
(3) comprise a Radio Data System facility, and
transmitting at least one further radio signal being an interception radio signal
(4, 4_1, 4_2, 4_n), wherein said interception radio signal (4, 4_1, 4_2, 4_n) comprises
information (25) in the Radio Data System frequency range of a second radio channel
(P2) being different from the first radio channel (P1),
wherein said information (25) is configured so as to manipulate said radio receivers
(3) to automatically tune said radio receivers (3) from a third radio signal (5) broadcasted
from an external, stationary broadcasting station (6) at said second channel (P2)
to said first radio channel (P1) to receive said traffic bulletin signal (2).