UMPIRES RAY GUN FOR USE IN WEAPON TRAINING SYSTEMS
United States Patent 3847396
A hand held ray gun for use in weapon training systems transmits a beam modulated in a first mode to allow an umpire directing the beam on a responsive target to check that the radio responder on the target is responding to the beam and operates in a second mode of modulation, selected by means of a manually operated switch, to allow the umpire to transmit a coded signal to `kill` the target vehicle, for example by disabling its electrical supply system.
US Patent References:
Testing apparatus
Foisy - April 1937 - 2077383
Hit indicator apparatus
Strauss - September 1963 - 3104478
Photosensitive light gun
Glaser - September 1964 - 3151248
LASER,WEAPON SIMULATOR
Redmond - May 1969 - 3447033
GUNNERY PRACTICE APPARATUS EMPLOYING LASER BEAMS
Ohlund - July 1969 - 3452453
Testing apparatus
Foisy - April 1937 - 2077383
Hit indicator apparatus
Strauss - September 1963 - 3104478
Photosensitive light gun
Glaser - September 1964 - 3151248
LASER,WEAPON SIMULATOR
Redmond - May 1969 - 3447033
GUNNERY PRACTICE APPARATUS EMPLOYING LASER BEAMS
Ohlund - July 1969 - 3452453
Application Number:
05/383026
Publication Date:
11/12/1974
Filing Date:
07/26/1973
View Patent Images:
Export Citation:
Assignee:
The Solartron Electronic Group Limited (Farnborough, Hampshire, EN)
Primary Class:
Other Classes:
434/22
International Classes:
F41G3/26; F41J5/02; F41G3/00; F41J5/00; F41J5/02
Field of Search:
273/101.1,101.2 35/25 356/4
US Patent References:
| 3588108 | April 1967 | Ormiston |
Primary Examiner:
Pinkham, Richard C.
Assistant Examiner:
Siskind, Marvin
Attorney, Agent or Firm:
Roylance, Abrams, Berdo & Kaul
Claims:
What is claimed is
1. Apparatus for use with a responsive target forming part of a weapon training system the target being of the type having detecting means for detecting the incidence of electromagnetic radiation modulated in different modes and having transmitting means operably connected to said detecting means for transmitting radio signals in response to said incident radiation, and with a selective circuit connected to receive signals from said detecting means and responsive to a predetermined mode of modulation of said radiation corresponding to a "kill" signal, the apparatus comprising in combination
2. Apparatus according to claim 1 wherein said first and second modes of modulation are characterised by different modulating frequencies.
3. Apparatus according to claim 1 wherein one of said first and second modes of modulation is characterised by alternation between two modulating frequencies.
4. Apparatus according to claim 1 wherein the indicating means provides in operation an indication visible through the aiming means.
5. Apparatus for use with a responsive target forming part of a weapon training system the target being equipped with detecting means for detecting the incidence of electromagnetic radiation and with transmitting means operably connected to said detecting means for transmitting radio signals in response to said incident radiation, and with a selective circuit connected to receive signals from said detecting means and responsive to only certain modes of modulation of said radiation corresponding to a "kill" signal, said apparatus comprising in combination
6. A weapon training system comprising
1. Apparatus for use with a responsive target forming part of a weapon training system the target being of the type having detecting means for detecting the incidence of electromagnetic radiation modulated in different modes and having transmitting means operably connected to said detecting means for transmitting radio signals in response to said incident radiation, and with a selective circuit connected to receive signals from said detecting means and responsive to a predetermined mode of modulation of said radiation corresponding to a "kill" signal, the apparatus comprising in combination
2. Apparatus according to claim 1 wherein said first and second modes of modulation are characterised by different modulating frequencies.
3. Apparatus according to claim 1 wherein one of said first and second modes of modulation is characterised by alternation between two modulating frequencies.
4. Apparatus according to claim 1 wherein the indicating means provides in operation an indication visible through the aiming means.
5. Apparatus for use with a responsive target forming part of a weapon training system the target being equipped with detecting means for detecting the incidence of electromagnetic radiation and with transmitting means operably connected to said detecting means for transmitting radio signals in response to said incident radiation, and with a selective circuit connected to receive signals from said detecting means and responsive to only certain modes of modulation of said radiation corresponding to a "kill" signal, said apparatus comprising in combination
6. A weapon training system comprising
Description:
This invention relates to ancillary equipment for weapon training systems and particularly, but not exclusively, for those in which a narrow beam of electromagnetic radiation is used to simulate the line of fire from a gun on an attacking vehicle and in which detectors mounted on a target detect such radiation and, by means of a radio link, signal back to the attacking vehicle that they are under fire or have been hit.
One such system is described in our U.S. Pat. No. 3,588,108 and although this system permits more effective training of tank crews in tactical exercises by allowing one tank to disable another by accurate simulated fire rather than by relying entirely on the judgement of umpires, which is frequently late and necessarily arbitrary, it has been found that there is still a need for umpires. Umpires need to be able to check, at a distance, that a tank crew's weapon training equipment is switched on and is operating in the target mode. The role of the umpire would be greatly enhanced moreover if he were able to disable any tank at will, thus, for example, simulating the effects of air strikes or mine fields.
Ray guns, such as are described in U.S. Pat. No. 2,070,529 are of course well known but these do not provide for operation in more than one mode nor do they provide for transmission from the target to show that equipment on the target is working without actually effecting a "kill."
With this need in mind there is provided according to the invention apparatus for use with a responsive target forming part of a weapon training system, said target being equipped with detecting means for detecting the incidence of electromagnetic radiation and with transmitting means operably connected to said detecting means for transmitting radio signals in response to said incident radiation and with a selective circuit connected to receive signals from said detecting means and responsive to at least one mode of modulation of said radiation corresponding to a "kill" signal, said apparatus comprising in combination a source for providing a collimated beam of electromagnetic radiation, modulating means co-operating with said source for modulating said beam in at least first and second modes, said first mode being adapted to activate said transmitting means to transmit without activating said selective circuit, and said second mode being adapted to activate said selective circuit on the target as a "kill" signal, manually operable switch means connected to said modulating means for selecting at will each of said modes of modulation and for causing the beam to be transmitted in said selected mode, aiming means connected to said source and aligned with said beam for aiming said beam at said target, radio receiving means for receiving the radio signals transmitted from said target in response to radiation from said beam incident on said target and indicating means connected to said receiving means for indicating that the detecting means on the target has detected the incidence of the beam.
The invention will now be described by way of non-limitative example by reference to the attached drawings, in which:
FIG. 1 shows a soldier umpire using equipment according to the invention.
FIG. 2 shows diagramatically further detail of the "umpire's gun" which forms part of the equipment.
FIG. 3 shows a view through the sight which forms part of the "umpire's gun."
FIG. 4 shows in greater detail the modulator depicted in FIG. 2.
Referring now to FIG. 1, a soldier, 1, is holding an "umpire's gun," 2, which comprises a body, 3, containing a source (not shown in this figure) which in operation provides a modulated collimated beam of electromagnetic radiation, and a sight, 5, aligned with said beam so that the user can aim the beam accurately towards a target (not shown in this figure).
A back pack, 6 contains a radio receiver 18 connected to an aerial, 7. The back pack also contains power supplies for the umpire's gun, 2, to which it is connected by a cable 19. The radio receiver 18 is connected to indicating lamps (not shown in this figure) placed at the eye piece, 8, of the sight.
Press button switches 9 and 10 are provided on the stock 11 of the umpire's gun for "firing" the gun in each of its modes of operation.
Referring now to FIG. 2 there is shown diagramatically and in part section the umpire's gun 2 in FIG. 1. The source of the modulated collimated beam of electromagnetic radiation comprises a convex collimating lens 13 and a Gallium Arsenide laser diode 12 situated substantially on the optical axis and in the focal plane thereof.
The laser diode 12 receives electrical pulses from a modulator 14 which may be operated in a plurality of modes, for example, by changing the frequency of pulses supplied to the laser 12. The required mode of modulation is determined by press switches 9 and 10. It is convenient to arrange for the laser to be fired in a first mode when one press button is pressed and in a second mode when both press buttons are pressed but it is evident that there are many different switches or arrangements of switches which could be used for these functions.
FIG. 3 shows the view through the eye-piece 8 of sight 5 when the umpire's gun 2 is correctly aimed at a target tank 16, being aligned with cross-hairs 15 of the sight 5. Indicator lamps 17 are provided in the sight 5 to give an indication to the soldier 1 without the need for him to move his eye from the eye-piece 8.
FIG. 4 shows further detail of the modulator 14 of FIG. 2. A monostable 30 which may conveniently be a type 74121 monostable multivibrator obtainable from ITT Semiconductors., Footscray, Kent., has an A terminal 32 which is connected to ground, a B terminal 34, a Q output 36 and timing terminals 38 and 40 between which a timing capacitor 42 is connected, terminal 40 being connected through resistor 44 to a common supply line 46.
The output 36 of monostable 30 is connected to the input 48 of a schmidt trigger 50 which may conveniently by type SN7413 obtainable from the same source as the monostable 30. Schmidt trigger 50 has an output 52 which is connected to the input 54 of a second similar schmidt trigger 56 which has an output 58. Output 58 is connected to one input 60 of a NAND gate 62 the other input of which 64 is connected to input 34 of multivibrator 30. The output 66 of NAND gate 62 is connected via resistor 68 to input 48 of trigger 50 the input 48 also being connected to ground via capacitor 70. A second monostable 72 identical to monostable 30 has an A input 74 which is connected to input 54 of AND gate 56 and a Q output 76 which is connected to input 34 of multivibrator 30. A timing capacitor 78 is connected between terminals 80 and 82 of monostable 72 and terminal 80 is connected by a resistor 84 to the supply line 46.
The timing terminal 40 of multivibrator 30 is connected via a resistor 90 to the collector of a transistor 92 the emitter of which is connected to supply line 46 and the base of which is connected to the junction of resistors 94 and 96. The other terminal of resistor 94 is connected to supply line 46 and the other terminal of resistor 96 is connected to terminal 98 of switch 9. The other terminal 100 of switch 9 is connected to ground.
Terminal 82 of monostable 72 is connected through a resistor 102 to the collector of transistor 104 the emitter of which is connected to supply line 46 and the base of which is also connected to supply line 46 via resistor 106. The base of transistor 104 is also connected via resistor 108 to the collector of transistor 110 the emitter of which is connected to terminal 98 of switch 9 and the base of which is connected through resistor 112 to supply line 46. The collector of transistor 110 is also connected to supply line 45 via resistor 114.
The collector of transistor 110 is also connected via capacitor 116 to the collector of a transistor 118 which is also connected via a resistor 120 to supply line 46. The emitter of transistor 118 is connected to terminal 98 of switch 9 and its base is connected via resistor 122 to supply line 46. A capacitor 124 is connected between the collector of transistor 110 and the base of transistor 118 and a capacitor 126 is connected between the collector of transistor 118 and the base of transistor 124. The supply line 46 is connected to terminal 128 of switch 10 the other terminal 130 of which 130 is connected to a power supply (not shown).
The Q output 76 of monostable 72 is connected to the input 64 of NAND gate 62 and to the B input 132 of a monostable 134, which may also be type SN74121, and has an A input 136 connected to ground and a Q output 138. A timing capacitor 140 is connected between timing terminals 142 and 144 of monostable 134 and terminal 144 is also connected via resistor 146 to a reference voltage 148.
Q output 138 is connected via resistor 150 and capacitor 152 in series to the base of a transistor 154 the emitter of which is connected to power supply 156. The base of transistor 154 is connected to power supply 156 via resistor 158 and the collector of transistor 154 is connected to ground via resistor 160. The collector of transistor 154 is also connected via resistor 162 and diode 164 in series to the gate 166 of a silicon controlled rectifier SCR 168. Gate 166 is connected via resistor 170 to ground. The cathode of SCR 168 is also connected to ground. The anode of SCR 168 is connected to a high voltage power supply 172 and to a capacitor 174, the other terminal of which is connected via resistor 176 to the cathode of laser diode 12. The anode of laser diode 12 is connected to earth. A protective diode 178 and a resistor 180 are connected in parallel across laser diode 12.
Monostables 30 and 72 are coupled together to form a multivibrator the pulse repetition frequency f 1 of which is determined primarily by timing capacitors 42 and 78 and resistors 44 and 84. The schmidt triggers 50 and 56 together with NAND gate 62 constitute a starting circuit to ensure that when power is supplied to the circuit by closure of switch 10 the circuit starts to oscillate. Monostable 134 is triggered by a pulse at the output 76 of monostable 72 to produce an output at Q output 138 which is amplified by transistor 154 and fires SCR 168. SCR 168 then discharges capacitor 174 through laser diode 12 which emits a pulse of infra red energy. It will be seen that the PRF of pulses from laser diode 12 is determined by the oscillation frequency f of a multivibrator formed by monostables 30 and 72.
This frequency f may be altered by switching in additional resistors 90 and 102 by means of transistors 92 and 104. Unless switch 9 is closed the terminal 98 is floating and neither transistor 92 nor 104 nor 110 nor 118 are conducting. When switch 9 is closed terminal 98 is grounded applying power to transistors 92, 104, 110 and 118. Transistor 92 is turned on and the effect of introducing resistor 90 into the timing circuit between terminal 40 and the power supply 46 is to change the frequency to a new higher frequency f 2 .
Transistors 110 and 118 are cross coupled in known fashion to form a multivibrator and the potential at the collector of transistor 110 will alternate between ground and that of the supply terminal 46. The effect of this is to switch on transistor 104 during those periods when transistor 110 is conducting and its collector is at ground potential. When transistor 104 is conducting resistor 102 is also brought into circuit between terminal 82 of monostable 72 and the supply 46; its effect is to raise the frequency of oscillation to a higher value f 3 .
Thus when switch 10 is operated the laser is fired at the first frequency f 1 ; when switches 9 and 10 are both operated the PRF of light pulses from the laser alternates between higher frequencies f 2 and f 3 at a rate determined by the time constants of the multivibrator formed by transistors 110 and 118.
In operation detectors on the target 16 receive radiation from the beam and are connected to frequency selective circuits adapted to discriminate between signals representative of each of the modes of modulation selected by press buttons 9 and 10. The first mode of modulation at the single frequency f 1 allows the soldier 1 to check that equipment on the target is switched on and is operating; a radio transmitter is mounted on the target and transmits when the beam is incident on the detectors. Signals from this radio transmitter are received by aerial 7 and radio receiver 18 which is connected to operate the lamps 17 in the eye piece 8 of the sight 5. Thus a visual indication is provided in the eye piece that the detectors and transmitter on the target tank are operative.
The frequency f 1 is characteristic of the umpire's gun and is a different frequency from that employed in the weapon simulation system e.g. for attack. Accordingly frequency selective circuits in the target tank are arranged so that no indication is given in the target tank that the beam from the umpire's gun is incident upon it.
Frequencies f 2 and f 3 on the other hand are the characteristic frequencies used in the weapon simulation system for "attack" and for "kill." Protective circuits in the equipment on the target tank are arranged so that the target tank only responds to the "kill" frequency f 3 after it has already received a beam modulated at the "attack" frequency f 2 . This has the effect of reducing the susceptibility of the equipment on the target tank to spurious "kills" but it requires that the umpire's gun operates first at "attack" frequency f 2 and then at "kill" frequency f 3 in order to effect a "kill." This is provided by alternation between two frequencies f 2 and f 3 as described.
When the protective circuit is overcome and a "kill" signal is detected by the frequency selective circuits receiving the signal from the detector on the target, a relay is operated to disable some or all of the functions of the target vehicle.
One such system is described in our U.S. Pat. No. 3,588,108 and although this system permits more effective training of tank crews in tactical exercises by allowing one tank to disable another by accurate simulated fire rather than by relying entirely on the judgement of umpires, which is frequently late and necessarily arbitrary, it has been found that there is still a need for umpires. Umpires need to be able to check, at a distance, that a tank crew's weapon training equipment is switched on and is operating in the target mode. The role of the umpire would be greatly enhanced moreover if he were able to disable any tank at will, thus, for example, simulating the effects of air strikes or mine fields.
Ray guns, such as are described in U.S. Pat. No. 2,070,529 are of course well known but these do not provide for operation in more than one mode nor do they provide for transmission from the target to show that equipment on the target is working without actually effecting a "kill."
With this need in mind there is provided according to the invention apparatus for use with a responsive target forming part of a weapon training system, said target being equipped with detecting means for detecting the incidence of electromagnetic radiation and with transmitting means operably connected to said detecting means for transmitting radio signals in response to said incident radiation and with a selective circuit connected to receive signals from said detecting means and responsive to at least one mode of modulation of said radiation corresponding to a "kill" signal, said apparatus comprising in combination a source for providing a collimated beam of electromagnetic radiation, modulating means co-operating with said source for modulating said beam in at least first and second modes, said first mode being adapted to activate said transmitting means to transmit without activating said selective circuit, and said second mode being adapted to activate said selective circuit on the target as a "kill" signal, manually operable switch means connected to said modulating means for selecting at will each of said modes of modulation and for causing the beam to be transmitted in said selected mode, aiming means connected to said source and aligned with said beam for aiming said beam at said target, radio receiving means for receiving the radio signals transmitted from said target in response to radiation from said beam incident on said target and indicating means connected to said receiving means for indicating that the detecting means on the target has detected the incidence of the beam.
The invention will now be described by way of non-limitative example by reference to the attached drawings, in which:
FIG. 1 shows a soldier umpire using equipment according to the invention.
FIG. 2 shows diagramatically further detail of the "umpire's gun" which forms part of the equipment.
FIG. 3 shows a view through the sight which forms part of the "umpire's gun."
FIG. 4 shows in greater detail the modulator depicted in FIG. 2.
Referring now to FIG. 1, a soldier, 1, is holding an "umpire's gun," 2, which comprises a body, 3, containing a source (not shown in this figure) which in operation provides a modulated collimated beam of electromagnetic radiation, and a sight, 5, aligned with said beam so that the user can aim the beam accurately towards a target (not shown in this figure).
A back pack, 6 contains a radio receiver 18 connected to an aerial, 7. The back pack also contains power supplies for the umpire's gun, 2, to which it is connected by a cable 19. The radio receiver 18 is connected to indicating lamps (not shown in this figure) placed at the eye piece, 8, of the sight.
Press button switches 9 and 10 are provided on the stock 11 of the umpire's gun for "firing" the gun in each of its modes of operation.
Referring now to FIG. 2 there is shown diagramatically and in part section the umpire's gun 2 in FIG. 1. The source of the modulated collimated beam of electromagnetic radiation comprises a convex collimating lens 13 and a Gallium Arsenide laser diode 12 situated substantially on the optical axis and in the focal plane thereof.
The laser diode 12 receives electrical pulses from a modulator 14 which may be operated in a plurality of modes, for example, by changing the frequency of pulses supplied to the laser 12. The required mode of modulation is determined by press switches 9 and 10. It is convenient to arrange for the laser to be fired in a first mode when one press button is pressed and in a second mode when both press buttons are pressed but it is evident that there are many different switches or arrangements of switches which could be used for these functions.
FIG. 3 shows the view through the eye-piece 8 of sight 5 when the umpire's gun 2 is correctly aimed at a target tank 16, being aligned with cross-hairs 15 of the sight 5. Indicator lamps 17 are provided in the sight 5 to give an indication to the soldier 1 without the need for him to move his eye from the eye-piece 8.
FIG. 4 shows further detail of the modulator 14 of FIG. 2. A monostable 30 which may conveniently be a type 74121 monostable multivibrator obtainable from ITT Semiconductors., Footscray, Kent., has an A terminal 32 which is connected to ground, a B terminal 34, a Q output 36 and timing terminals 38 and 40 between which a timing capacitor 42 is connected, terminal 40 being connected through resistor 44 to a common supply line 46.
The output 36 of monostable 30 is connected to the input 48 of a schmidt trigger 50 which may conveniently by type SN7413 obtainable from the same source as the monostable 30. Schmidt trigger 50 has an output 52 which is connected to the input 54 of a second similar schmidt trigger 56 which has an output 58. Output 58 is connected to one input 60 of a NAND gate 62 the other input of which 64 is connected to input 34 of multivibrator 30. The output 66 of NAND gate 62 is connected via resistor 68 to input 48 of trigger 50 the input 48 also being connected to ground via capacitor 70. A second monostable 72 identical to monostable 30 has an A input 74 which is connected to input 54 of AND gate 56 and a Q output 76 which is connected to input 34 of multivibrator 30. A timing capacitor 78 is connected between terminals 80 and 82 of monostable 72 and terminal 80 is connected by a resistor 84 to the supply line 46.
The timing terminal 40 of multivibrator 30 is connected via a resistor 90 to the collector of a transistor 92 the emitter of which is connected to supply line 46 and the base of which is connected to the junction of resistors 94 and 96. The other terminal of resistor 94 is connected to supply line 46 and the other terminal of resistor 96 is connected to terminal 98 of switch 9. The other terminal 100 of switch 9 is connected to ground.
Terminal 82 of monostable 72 is connected through a resistor 102 to the collector of transistor 104 the emitter of which is connected to supply line 46 and the base of which is also connected to supply line 46 via resistor 106. The base of transistor 104 is also connected via resistor 108 to the collector of transistor 110 the emitter of which is connected to terminal 98 of switch 9 and the base of which is connected through resistor 112 to supply line 46. The collector of transistor 110 is also connected to supply line 45 via resistor 114.
The collector of transistor 110 is also connected via capacitor 116 to the collector of a transistor 118 which is also connected via a resistor 120 to supply line 46. The emitter of transistor 118 is connected to terminal 98 of switch 9 and its base is connected via resistor 122 to supply line 46. A capacitor 124 is connected between the collector of transistor 110 and the base of transistor 118 and a capacitor 126 is connected between the collector of transistor 118 and the base of transistor 124. The supply line 46 is connected to terminal 128 of switch 10 the other terminal 130 of which 130 is connected to a power supply (not shown).
The Q output 76 of monostable 72 is connected to the input 64 of NAND gate 62 and to the B input 132 of a monostable 134, which may also be type SN74121, and has an A input 136 connected to ground and a Q output 138. A timing capacitor 140 is connected between timing terminals 142 and 144 of monostable 134 and terminal 144 is also connected via resistor 146 to a reference voltage 148.
Q output 138 is connected via resistor 150 and capacitor 152 in series to the base of a transistor 154 the emitter of which is connected to power supply 156. The base of transistor 154 is connected to power supply 156 via resistor 158 and the collector of transistor 154 is connected to ground via resistor 160. The collector of transistor 154 is also connected via resistor 162 and diode 164 in series to the gate 166 of a silicon controlled rectifier SCR 168. Gate 166 is connected via resistor 170 to ground. The cathode of SCR 168 is also connected to ground. The anode of SCR 168 is connected to a high voltage power supply 172 and to a capacitor 174, the other terminal of which is connected via resistor 176 to the cathode of laser diode 12. The anode of laser diode 12 is connected to earth. A protective diode 178 and a resistor 180 are connected in parallel across laser diode 12.
Monostables 30 and 72 are coupled together to form a multivibrator the pulse repetition frequency f 1 of which is determined primarily by timing capacitors 42 and 78 and resistors 44 and 84. The schmidt triggers 50 and 56 together with NAND gate 62 constitute a starting circuit to ensure that when power is supplied to the circuit by closure of switch 10 the circuit starts to oscillate. Monostable 134 is triggered by a pulse at the output 76 of monostable 72 to produce an output at Q output 138 which is amplified by transistor 154 and fires SCR 168. SCR 168 then discharges capacitor 174 through laser diode 12 which emits a pulse of infra red energy. It will be seen that the PRF of pulses from laser diode 12 is determined by the oscillation frequency f of a multivibrator formed by monostables 30 and 72.
This frequency f may be altered by switching in additional resistors 90 and 102 by means of transistors 92 and 104. Unless switch 9 is closed the terminal 98 is floating and neither transistor 92 nor 104 nor 110 nor 118 are conducting. When switch 9 is closed terminal 98 is grounded applying power to transistors 92, 104, 110 and 118. Transistor 92 is turned on and the effect of introducing resistor 90 into the timing circuit between terminal 40 and the power supply 46 is to change the frequency to a new higher frequency f 2 .
Transistors 110 and 118 are cross coupled in known fashion to form a multivibrator and the potential at the collector of transistor 110 will alternate between ground and that of the supply terminal 46. The effect of this is to switch on transistor 104 during those periods when transistor 110 is conducting and its collector is at ground potential. When transistor 104 is conducting resistor 102 is also brought into circuit between terminal 82 of monostable 72 and the supply 46; its effect is to raise the frequency of oscillation to a higher value f 3 .
Thus when switch 10 is operated the laser is fired at the first frequency f 1 ; when switches 9 and 10 are both operated the PRF of light pulses from the laser alternates between higher frequencies f 2 and f 3 at a rate determined by the time constants of the multivibrator formed by transistors 110 and 118.
In operation detectors on the target 16 receive radiation from the beam and are connected to frequency selective circuits adapted to discriminate between signals representative of each of the modes of modulation selected by press buttons 9 and 10. The first mode of modulation at the single frequency f 1 allows the soldier 1 to check that equipment on the target is switched on and is operating; a radio transmitter is mounted on the target and transmits when the beam is incident on the detectors. Signals from this radio transmitter are received by aerial 7 and radio receiver 18 which is connected to operate the lamps 17 in the eye piece 8 of the sight 5. Thus a visual indication is provided in the eye piece that the detectors and transmitter on the target tank are operative.
The frequency f 1 is characteristic of the umpire's gun and is a different frequency from that employed in the weapon simulation system e.g. for attack. Accordingly frequency selective circuits in the target tank are arranged so that no indication is given in the target tank that the beam from the umpire's gun is incident upon it.
Frequencies f 2 and f 3 on the other hand are the characteristic frequencies used in the weapon simulation system for "attack" and for "kill." Protective circuits in the equipment on the target tank are arranged so that the target tank only responds to the "kill" frequency f 3 after it has already received a beam modulated at the "attack" frequency f 2 . This has the effect of reducing the susceptibility of the equipment on the target tank to spurious "kills" but it requires that the umpire's gun operates first at "attack" frequency f 2 and then at "kill" frequency f 3 in order to effect a "kill." This is provided by alternation between two frequencies f 2 and f 3 as described.
When the protective circuit is overcome and a "kill" signal is detected by the frequency selective circuits receiving the signal from the detector on the target, a relay is operated to disable some or all of the functions of the target vehicle.