This invention relates to the missile technology and, more especially, this invention relates to portable surface-to-air missile systems.

There are already known portable surface-to-air missile systems, which have been designed to hit targets moving at low altitudes. One such known portable surface-to-air missile system is disclosed in international Patent Application No. WO 9816794, publication date 23 April 1998. This known portable surface-to-air missile system comprises of a guided missile with an optical autonomous guidance head and a launcher connected to it, which includes a transport-and-launch container, a power supply unit, and also a device increasing the precision of hitting. However, the known system does not ensure separation of deception targets from real ones, and therefore the efficiency of the known system is low.

Another known system is disclosed in USA Patent No.656036, published 20 May 2003. This known system claims enhanced precision of hitting high-speed air targets. However, this system is mainly designed for artillery, and it includes a long rod piercing body as a hitting element. The placement of light sensors inside such a rod, and the use of optical lenses substantially complicate this known system.

There is also a known high-precision optical guidance missile, which is disclosed in USA Patent No. 6142412, published 7 November 2000. This guidance missile comprises an optical autonomous guidance head, a launcher and a power supply unit. While in flight, the missile course needs to be corrected, which requires the reception of a relevant signal from a ground installation. This substantially complicates both the missile design (because Kalman filters need to be installed) and its launch. In addition, the guidance missile requires additional substantial costs.

From its aim, specifications and technical effect that may be achieved, the closest device to the present invention is an Igla-1 - 9K310 portable surface-to-air missile system. This system includes a missile with a frequency modulated autonomous guidance infrared head with a selector and a launcher connected to it, which includes a transport and launch container, a launcher, and a power supply unit (Igla-1 portable surface-to-air missile system (9K310) - see Technical Description and Operations Manual for 9K310 TO, Moscow, Voyennoye Izdatelstvo Publishing House, 1983).

For a portable surface-to-air missile system, anti-flare requirements are important. The main disadvantage of the Igla-1 - 9K310 portable surface-to-air missile system is that it has an inadequate flare-resistance.

In order to fight surface-to-air missiles using infrared guidance systems, up-to-the-date combat aircraft utilize thermal deception targets as infrared deception flares. The thermal deception targets are ejected by the carrier aircraft. The energy parameters of an infrared deception flare are in excess of the energy parameters of its carrier aircraft. The infrared guidance system of the missile that was tracking the radiation from the combat aircraft, switches over to track the more powerful radiation source, i.e. the infrared deception flare. The infrared deception flare moves in space with retard to the combat aircraft. At a period in time, the target that has been aimed at and the infrared deception flare do not fit into the sight of the missile guidance system. Since the missile guidance system is tracking a more powerful infrared deception flare, the target that has been aimed at goes out of the missile guidance system, with the result that the target is missed.

The present invention is aimed at minimising the vulnerability of portable surface-to-air missiles to flares. This is effected by equipping the infrared autonomous guidance head of the portable surface-to-air missile with a system distinguishing the target from an infrared deception flare.

In accordance with an embodiment of the present invention, there is provided a portable surface-to-air missile system, which comprises a missile with a frequency-modulated infrared autonomous guidance head and a selector, which is electrically and pneumatically connected to a launcher, which includes a transport and launch container, a launch mechanism and a power supply unit, characterised by implementation of the selector of the infrared autonomous guidance head with the opportunity to use kinematic differences between a real target and a deceptive flare, while the launcher has an indicator changing the operating program of the selector, with the selector made of interconnected analyser, logic unit, and function circuit, an input of the analyser electrically connected to an output of a light signal amplifier, with an output of the analyser electrically connected to a first input of the logic unit, with a second input of the logic unit electrically connected to the launcher, and with a first output of the logic unit electrically connected to a first input of the function circuit, with a second input of the function circuit electrically connected to an output of a cage winding, and with an output of the function circuit electrically connected to one of the inputs of the correction amplifier.

The analyser may be implemented as an electrically interconnected amplifier, two comparators and timer, with an input of the amplifier electrically connected to the output of the light signal amplifier, with the output of the amplifier electrically connected to inputs of the comparators, and with outputs of the comparators electrically connected to the first input of the logic unit.

The logic unit may be a switch.

In one embodiment of the invention, the function circuit is implemented as electrically interconnected first and second switches, first and second function formers, a generator, and an analog random-access memory, with a first input of the analog random-access memory electrically connected to the output of the correction amplifier, with a second input of the analog random-access memory electrically connected to an output of the generator, with an output of the analog random-access memory electrically connected to the input of the first function former, with the output of the first function former electrically connected to the first input of the first switch, with the second input of the first switch electrically connected to the first output of the logic unit, with the output of the first switch electrically connected to one of the inputs of the correction amplifier, with the input of the second function former electrically connected to the output of the cage winding, with the output of the second function former electrically connected to the first input of the second switch, with the second input of the second switch electrically connected to the first output of the logic unit, and with the output of the second switch electrically connected to one of the inputs of the correction amplifier.

The use of a programmed selector in the missile guidance system enables utilisation of kinematic differences between the real target and deceptive flares, while the launcher has an indicator changing selector operation.

The invention will now be described solely by way of example and with reference to the accompanying drawings in which:

• Figure 1 is an overall block diagram of a portable surface-to-air missile system;
• Figure 2 is a block diagram of a programmed selector;
• Figure 3 is a block diagram of an analyser; and
• Figure 4 is a block diagram of function circuits.

Referring to Figure 1, there is shown missile 1, an IRAGH 2, an optics and mechanics unit 3, an electronic compartment 4, programmed selectors 5, a launcher 6, a transport and launch container 7, a launch mechanism 8, and a ground power supply 9.

In Figure 2, there is shown an analyser 10, a logic unit 11, and a function circuit 12.

In Figure 3, there is shown an amplifier 13, a first comparator 14, a second comparator 15, and a timer 16.

In Figure 4, there is shown an analog random-access memory 17, a generator 18, a first function former 19, a first switch 20, a second function former 21, and a second switch 22.

The portable surface-to-air missile system operates as follows.

The first input of missile 1 is electrically connected to the first output of the IRAGH 2. The output of missile 1 is kinematically connected to the body of IRAGH 2. The output of the optics and mechanics unit 3 is electrically connected to the input of the electronic compartment 4, with the programmed selector 5 comprising a constituent part of it. The output of the electronic compartment 4 is electrically connected to the input of the optics and mechanics unit 3.

The launcher 6 comprises of the transport and launch container 7, the launch mechanism 8 and the ground power supply 9. The first output of the transport and launch container 7 is electrically connected to the second input of missile 1. The second output of the transport and launch container is electrically and pneumatically connected to the input of the IRAGH 2. The second output of the IRAGH 2 is electrically connected to the first input of the transport and launch container 7. The third output of the transport and launch container 7 is electrically connected to the input of the LM 8. The output of the LM 8 is electrically connected to the second input of the transport and launch container 7. The fourth output of the transport and launch container 7 is kinematically connected to the input of the ground power supply 9. The output of the ground power supply 9 is electrically and pneumatically connected to the third input of the transport and launch container 7.

The electric signal is supplied from the light signal amplifier to the input of the analyser which contains data on sources of input light signals, on the target and infrared deception flares. The output of the analyser is electrically connected to the first input of the logic unit (switch) 11. The electric signal from the transport and launch container 7 goes into the second input of the logic unit 11. The electric signal from the first output of the logic unit 11 goes to the first input of the function circuit 12. The electric signal from the output of the cage winding (which is part of the optics and mechanics unit) goes into the second input of the function circuit 12. An electric signal from the output of the function circuit 12 goes to one of the inputs of the correction amplifier (which is part of the electronic compartment 4).

The electric signal from the output of the light signal amplifier (which is part of the electronic compartment 4) goes to the input of the amplifier 13. The electric signal from the first output of the amplifier 13 goes to the input of the first comparator 14. The electronic signal from the second output of the amplifier 13 goes to the input of the second comparator 15. The outputs of the comparators 14 and 15 are electrically connected to the first and second inputs of the timer 16, respectively. The output of the timer 16 is electrically connected to the first input of the logic unit 11.

The electric signal from the output of the correction amplifier (which is part of the electronic compartment 4) goes into the first input of the analog random-access memory 17. The electric signal from the generator 18 goes to the second input of the analog random-access memory 17. The electric signal from the output of the analog random-access memory 17 goes into the input of the first function former 19. The electric signal from the first function former 19 goes into the first input of the first switch 20. The electric signal from the output of the logic unit 11 goes into the second input of the first switch 20. The electric signal from the output of the first switch 20 goes into the input of the correction amplifier (which is part of the electronic compartment 4). The electric signal from the output of the cage winding (which is part of the optics and mechanics unit 3) goes into the input of the second function former 21. The electric signal from the output of the function former 21 goes into the first input of the second switch 22. The electric signal from the output of the logic unit 11 goes into the second input of the switch 22. The electrical signal from the output of the switch 22 goes into the input of the correction amplifier (which is part of the electronic compartment 4).

In the device described above, the first function former 19 is forming an electric signal at its output, which is a function of the angular velocity ω of the target, for example, K₁ *(ω), where K₁ = const. The second function former 21 is forming an electric signal at its output, which is a function of the target bearing ϕ, for example, K₂ * ϕ, where K₂ = const.

The trajectory and kinematic difference between the target being attacked and the infrared deception flare is based on the difference between the masses of the infrared deception flare and high-speed targets. Because of a substantial speed of the target and a swift spatial deceleration of the infrared deception flare, regardless of the direction of its dropping, at the end of the day, the infrared deception flare will always be behind the target in space and the IRAGH coordinate system.

The optical system of the missile IRAGH receives an infrared signal about the targets in its sight and delivers an electric signal about the targets to the electronic compartment of the IRAGH. The electronic compartment forms and delivers electric commands both to the executing mechanism of the IRAGH control system (correction winding), which corrects the position of the IRAGH optical system axis, and to the actuating mechanism for the missile rudders (not shown on the drawings) during the flight.

The programmed selector forms commands for the actuating mechanism for the IRAGH control system (correction winding), which corrects the position of the IRAGH optical system axis, with the infrared deception flare going out of the missile guidance sight and the target it has been aimed at remaining in the sight. This is the way of ensuring that the target the missile has been aimed at is hit.

The principle of operation of the infrared deception flare trajectory and kinematics selector is in selecting from among the sources located in the sight those which have moved in space along the vector of angular velocity ω or along the bearing ϕ (in proportion to the signal in the cage winding), which has been set during IRAGH operation following the "launch" command.

Upon arriving of an electric signal from the light signal amplifier to the analyser, the signal is amplified and compared in the first comparator with the value set beforehand. If the given value has been exceeded, the first comparator 14 will send an electric signal about the appearance of an infrared deception flare to the logic unit 11 through the timer 16. The output signal from the logic unit 11 opens the first switch 20 and closes the second switch 22. Upon receipt of a correction signal and a signal from the generator 18 by the inputs of the ARAM 17, the ARAM 17 memorises with the given frequency of updating the correction signal, and delivers it to the first function former 19 and further through the open switch 20 to the correction amplifier, to which an electric signal which is a function of the angular velocity w comes. This signal corrects the gyroscope axis position.

Having sent the "launch" command (after the missile launch), the logic unit with a pre-selected delay time gives the command to close the first switch 20 and open the second switch 22. As a result, a signal from the second function former 21, which depends upon the bearing ϕ, will come to the input of the correction amplifier (in the electronic compartment 4). As the signal from the amplifier 13 decreases, the second comparator 15 will work and switch off the timer 16 (or the timer will be off following the operation time set). When the signal from the analyser 10 disappears, the logic unit 11 will block the signal from the outputs of the switches 20 and 22.

It is to be appreciated that the embodiment of the invention described above with reference to the accompanying drawings has been given by way of example only and that modifications may be effected.