Personal tracking system predominantly for children

Description

Field of the Invention

[0001] The invention relates to personal tracking systems for the location and tracking of movements of persons, particularly for children in distress.

Background Art

[0002] It is a worry for many parents and for the authorities that it can be difficult to locate children who stray from or are removed from their parents' direct supervision and control. In the most innocent case a child may simply stray and become lost. In more sinister circumstances the child may be abducted. In either case there is a need to be able to locate that child quickly and positively, and a range of devices have been proposed for that purpose.

[0003] US-A-5629678 discloses a system which incorporates a transceiver which is surgically implanted beneath the skin of a child to be monitored. Normally the transceiver is inactive, but it can be remotely activated by a supervising adult who holds the corresponding receiver. The system has disadvantages. The transceiver must be of very small size because of the implantation technique, and its range is therefore limited. The need for surgery in order to implant the transceiver is a great barrier to popular acceptance of the system.

[0004] Other systems require the child to carry a mobile transmitter unit. AU-A-9511412, for example, discloses a personal finder in which the transmitting unit is a hand-held plastic box, containing a printed circuit board carrying all the electronic components and an antenna. The receiving unit includes a display to show information relating to the lost child, such as the direction and distance of the child from the receiving unit. However if the child has lost possession of the mobile transmitter unit, either by misplacing it or by having it forcibly taken away, the receiving unit can identify only the position of the transmitter unit and not of the child.

[0005] Thus although the technology is available to manufacture a location and tracking device which in theory could enable the rapid location of missing children, the reality is that no such system is commercially available because nobody has yet devised a system which is secure and reliable and which identifies and meets the actual needs of the parents and police forces who will ultimately be using the system.

The Invention

[0006] The invention provides a personal tracking system to permit the accurate location of a missing child, comprising:

a mobile transmitter incorporated into a wrist or ankle bracelet to be worn by the child;

means for enabling and disabling the transmitter unit;

means for causing the transmitter unit to transmit an emergency signal if the bracelet is severed or removed while the transmitter unit is enabled;

means for activating the enabled transmitter unit to cause it to transmit a location signal; and

a portable receiver unit for receiving the emergency signal or the location signal and translating that signal into a visual display of information.

[0007] The system is used as follows. The bracelet is placed on the wrist or ankle of the child to be monitored, and enabled. If the transmitter and receiver units are both two-way transponders, the enabling may be by means of a PIN transmitted from the receiver unit. After enabling, the bracelet cannot be removed either at its clasp or destructively without causing the transmitter to transmit the emergency signal.

[0008] The emergency signal is preferably a radio signal receivable by the receiver unit to actuate an audible and/or visual alarm. Preferably the transmitter unit further comprises means for causing the transmitter unit to transmit its emergency signal under the control of the wearer even when the bracelet is neither severed nor removed. This facility, equivalent to a 'panic button' on the bracelet for summoning help if the wearer recognizes a potentially alarming situation, means that the person with the receiver unit, generally the parent or supervising adult, is immediately alerted to the fact that the child is in need of help. The alarm given at the receiving unit may be the same whatever the nature of the initiation of the emergency signal, or it may vary depending on whether the actuation of the emergency signal is by means of the 'panic button' or by severing or removal of the bracelet.

[0009] Whether the emergency signal has been transmitted or not, the location signal enables the receiver unit to receive and display information relating to the location of the transmitter unit. The information displayed is preferably:

(a) the direction of the transmitter unit relative to the receiver unit;

(b) the distance of the transmitter unit from the receiver unit; and

(c) the speed of movement of the transmitter unit.

[0010] If desired, the information elements (a) and (b) above may be amalgamated into a single element of information defining the exact location of the transmitter unit.

[0011] Information relating to the speed of movement of the transmitter unit is of very great importance in the location of a missing child. If the child wearing the transmitter unit is stationary, that may be because it is injured. If it is moving at a slow walking pace, that may indicate that it is lost and trying to find its way. If it is moving at a fast walking or running pace, that may indicate panic. Anything in excess of a running pace indicates that the wearer of the bracelet is in a motor vehicle.

[0012] The location signal may be transmitted for the whole of the time that the transmitter unit is enabled, so that at any time the holder of the receiver unit can look at the display on the receiver unit and see the position and speed of movement of the transmitter unit. To protect the airwaves from potential saturation by too many transmitted signals, however, the activation of the enabled transmitter unit is preferably achievable remotely, by means of an activating signal from the receiver unit. To achieve this the transmitter and receiver units must both be two-way transponders as indicated above in connection with remote enabling. The enabled transmitter unit can be worn for any length of time without activation, but starts to transmit its location signals when it receives a transmitted activation signal from the receiver unit. The activation signal preferably incorporates an identification code, such as the PIN referred to above, to ensure that the intended transmitter unit is activated. For example, one family could have a number of children, each with his or her own transmitter unit. When one child becomes lost, the PIN associated with that child's transmitter unit is broadcast by the parent's receiver unit, and that particular one transmitter unit is thereby activated.

[0013] When it is intended to remove the bracelet, the transmitter unit is first disabled, for example by a transmitted PIN and disabling code from the receiver unit.

[0014] The bracelet clasp can then be unfastened and the bracelet removed without activating the alarm signal.

[0015] The transmitter unit is preferably a self-powered unit about the size of a wristwatch. Flexible straps of the bracelet extend around the wrist or ankle of the wearer and are fastened by a clasp. Wires or electrically conductive strips in the straps complete a circuit when the clasp is fastened, and whenever that circuit is broken while the transmitter unit is enabled, as it would be if the clasp were undone or the straps severed to remove the unit, the emergency transmission is initiated.

[0016] The receiver unit may be a unit about the size of a portable telephone. Indeed the receiver unit may double as a portable telephone, as much of the transmit and receive circuitry can be shared between the two functions. Either such a portable telephone may have the full range of cellular telephone attributes or it may be a telephone restricted to calls to the emergency services only so that assistance may be summoned in the case of a lost child.

[0017] The signals transmitted by the transmitter unit may be any telephonic signals but are preferably radio signals. The signals may be digital or analog, and the tracking and location may use any available technology. The existing cellular telephone network may be used for location by triangulation, for example, or satellite tracking may be utilized.

Claims

1. A personal tracking system to permit the accurate location of a missing child, comprising:

a mobile transmitter incorporated into a wrist or ankle bracelet to be worn by the child;

means for enabling and disabling the transmitter unit;

means for causing the transmitter unit to transmit an emergency signal if the bracelet is severed or removed while the transmitter unit is enabled;

means for activating the enabled transmitter unit to cause it to transmit a location signal; and

a portable receiver unit for receiving the emergency signal or the location signal and translating that signal into a visual display of information.

2. A personal tracking system according to claim 1, wherein the transmitter unit further comprises means for causing the transmitter unit to transmit its emergency signal under the control of the wearer even when the bracelet is neither severed nor removed.

3. A personal tracking system according to claim 1 or claim 2, wherein the bracelet of the transmitter unit comprises flexible straps to extend around the wrist or ankle of the wearer, a clasp for fastening the bracelet, and wires or electrically conductive strips in the straps to complete a circuit when the clasp is fastened, wherein breaking that circuit while the transmitter unit is enabled causes initiation of the emergency transmission.

4. A personal tracking system according to any preceding claim, wherein the transmitter unit is a transponder capable of reacting to a transmitted signal for the remote enabling and disabling of the transmitter unit.

5. A personal tracking system according to claim 4, wherein the receiver unit is also a transponder, capable of transmitting the enabling and disabling commands to the transmitter unit.

6. A personal tracking system according to claim 5, wherein the enabling and disabling transmitted signals are uniquely coded by means of a PIN recognizable by the mobile transmitter unit.

7. A personal tracking system according to claim 5 or claim 6, wherein the means for activating the enabled transmitter unit is also a transmitted signal from the receiver unit, and is uniquely coded by means of a PIN recognizable by the mobile transmitter unit.

8. A personal tracking system according to any preceding claim, wherein the audible receiver unit incorporates means for displaying, from the received location signal, information relating to the direction and distance of the transmitter unit from the receiver unit, and the speed of movement of the transmitter unit.

9. A personal tracking system according to any of claims 1 to 7, wherein the audible receiver unit incorporates means for displaying, from the received location signal, information relating to the absolute coordinates to define the exact location of the transmitter unit, together with information relating to the speed and movement of the transmitter unit.