PORTABLE HIT INDICATOR APPARATUS

Abstract: A portable indicator apparatus for detecting when an object at a target area has been hit by replicated indirect ammunition fire, comprising radio frequency receiver means (96), attached to the object, for receiving radio frequency actuating signals; decoder means (98) for determining if the radio frequency actuating signals designate that the object has been hit; and means (100), responsive to said decoder means (98), for signifying when the object has been hit by the replicated ammunition fire.

Description: The present invention relates to a portable indicator apparatus for use with a method and apparatus for simulating the effectiveness of a selected ammunition within a selected actual geographical target area. In the military there is the need to employ lethal weapons in a non-lethal manner so that equipment and personnel can be trained in realistic battle environments without the risk of being damaged or injured. This ability to realistically train is one of the highest priorities for the armed forces so that personnel can be trained to survive in battle rather than be killed, which can occur as a result of training exercises in which personnel are not immediately and individually advised of the effect of some action in the staged battle. At present, there is a laser-based training system, referred to as multiple integrated laser engagement system (MILES), wherein direct, line-of-sight fire between soldiers or between tanks can be replicated or simulated. With this prior system a laser apparatus on each weapon is activated to produce a laser beam directed at the target when the trigger on the weapon is pulled. If the laser beam strikes a sensor on the target, the target's weapon is disabled by a disabling unit carried by the target, thereby immediately indicating that the target has been hit. This has proved to be a useful system; however, its usefulness is limited to direct fire, visual line-of-sight actions so that the laser can be used without interference. Therefore, there is the need for a system which can replicate or simulate the real-time effect of indirect fire, such as artillery fire, thereby enabling combined arms battles to be staged for realistically training personnel. USA-3104478 and DE-A-3332582 refer to direct line of sight techniques of simulating combat, and as such cannot simulate the effects of indirect fire. The need for some type of indirect fire simulating system has long been recognised and one earlier proposal has suggested using satellites to receive signals from the remote location where the indirect firing weapon is located and then for sending signals to the target area. Such a proposal is technologically sophisticated; however, it is too expensive and requires a sensing device too heavy for personnel to carry and still be able properly to manoeuvre in a realistic training environment. Another proposal uses a foam rubber bullet, which is launched by a mortar-type device and is detonated in the air to send an acoustic signal which can actuate the presently used MILES sensors carried by the personnel and equipment within the target area, but this gives an unrealistic effect. Since both lasers and microwaves can be adversely affected by the environment where the training is to occur, such as by foliage that is found in battles conducted in wooded areas these forms of transmission are not suitable for the flexible type of system we desired. Therefore, there is the general need for a system which simulates the effectiveness of multiple types of weaponry, particularly indirect munitions such as artillery fire, to provide a combined arms simulation technique useful in training military units in various battle environments. Preferably the system should be able to be used with the MILES system presently used for direct fire replication and be able to be constructed utilising government-furnished equipment and non-developmental items to reduce the cost. The system should require minimum personnel and training to operate and should be available for all sizes of military units, such as from the platoon through corps. Use by such units should not interfere with their normal operation (e.g. use of the system should not alter the realism with which a battle is simulated). Such a system should also be operational in various types of environments where the fire to be replicated can occur (e.g. rain, fog, mountains, forests). According to co-pending application 86305296.5 (EP-A-0209322) there is provided a method of simulating, within a selected target area, the effectiveness of one of a number of types of ammunition selected, said method being charactersied in that it comprises the steps of:- (a) transmitting control signals from a master station, said signals being indicative of the type of ammunition selected and the target area selected; (b) transmitting, in response to the control signals, a plurality of electromagnetic wave transmissions which traverse the selected target area; and (c) identifying, in response to the electromagnetic wave transmissions, the effect of the selected ammunition at the selected target area. EP-A-0209322 also provides apparatus for simulating, within a selected target area, the effectiveness of one of a number of types of ammunition selected, said apparatus comprising:- (a) a master station transmitter for transmitting master control signals indicative of the type of ammunition selected and the target area selected; (b) a plurality of remote electromagnetic wave transmitters, responsive to control signals from said master station transmitter, said transmissions being capable of traversing the selected target area; and (c) indicators positionable in said target area, responsive to said plurality of transmissions, to indicate the effect of the selected ammunition at the selected target area. Such a method and apparatus are specifically adaptable for use in replicating combined arms fire support for use in training military units. They define a realistic zone affected by indirect fire and specify whether objects within the zone have been hit. The apparatus may be interfaced with the MILES system to provide a complete training package therewith. The system can be partially constructed with commercially available equipment and requires minimum personnel and training to operate, and the system can be used for various sizes of military units without interfering with their normal operations. Preferably the method and apparatus utilise radio frequency signals, thereby permitting the system to be used in various types of environments. According to the present invention there is provided a portable indicator apparatus for detecting when an object at a target area has been hit by replicated indirection ammunition fire, comprising radio frequency receiver means, attached to the object, for receiving radio frequency actuating signals to be emitted from a plurality of remote actuators; and means, responsive to decoder means, for signifying when the object has been hit by the replicated ammunition fire characterised in that the decoder means includes means for programming said apparatus with a plurality of probabilities for a predetermined type of object to be hit, wherein each of the probabilities is assigned to a respective type of replicated indirect ammunition fire, so that in response to receiving in order said radio frequency actuating signals, which are encoded to designate at least one type of replicated indirect ammunition fire, said means determines whether the actuating signals designate that the object has been hit. The present invention could be used for simulating other types of weaponry, such as chemicals, be used to test new systems to evaluate their utility before production and be used as a remote actuation system, specifically one which can be interfaced with the global positioning system (GPS). In order that the present invention will more readily be understood, the following description is given, merely by way of example, reference being made to the accompanying drawings, in which:- Figure 1 is a block diagram of one embodiment of apparatus according to EP-A-0209322, shown with an exemplary target area and exemplary ammunition. Figure 2 is an illustration of a specific environment in which the apparatus is deployed for replicating indirect fire support. Figure 3 is a block diagram of a master station and three remote actuators operating to define and communicate with an affected geographical zone within a target area. Figure 4 is a functional block diagram of the apparatus. Figure 5 is a functional block diagram of one of the remote actuators. Figure 6 is a more detailed function block diagram of the remote actuator shown in Figure 5. Figure 7 is a functional block diagram of an indicator unit according to the present invention and for use with the apparatus. Figure 8 is a more detailed block diagram of the indicator unit shown in Figure 7. Figures 9A-9D are diagrams showing different modes of operation of the apparatus. Figure 10 shows a time line depicting the interrelationship of the operations of the apparatus and the indirect fire whose effectiveness is to be simulated. Figures 11A-11C show block diagrams of the system timing. Figures 12A-12B depict the message structure between the master station and remote actuators and between the remote actuators and the indicator units. Figure 13 is a block diagram of a logic circuit implemented in the indicator units. Figure 14 illustrates contemplated enhancements for use with the indicator units and the MILES system. Figure 1 depicts an actual geographical zone 2 across which the indicated eighteen personnel and one truck are dispersed. In the zone 2 of the target area there is to be replicated the firing of one volley (six rounds) of a selected type of ammunition, specifically shown as a dual purpose improved conventional munition (DPICM). The effect these six rounds are to have on the personnel and the truck located in the zone 2 is simulated by the system which includes a master station 4, remote actuators 6, and indicators 8. Preferably indicators 8 are applied to the indicator/disabling units of a MILES system 10 known in the art (therefore, the indicators 8 are sometimes referred to herein as "appliques" in that they are "applied" to the MILES system 10). Therefore, the preferred embodiment of the present invention emulates computed munitions effects at the point of impact for fire support munitions, with these effects based on information from the Joint Munitons Effectiveness Manuals. This emulation is implemented by the master station 4 and remote actuators 6 using radio frequency energy to activate the appliques 8. Figure 2 illustrates the apparatus deployed in the field for the purpose of simulating the effect of ammunition fired from a weapon 12 at a target area 14. The master station 4 is shown in a wheeled vehicle 16 located near the weapon 12. The remote actuators 6 are located in spaced wheeled vehicles 18,20,22 and positioned between the master station and the target area 14. The master station is operated by an individual within the vehicle 16, whereas the remote actuators 18,20,22 do not need any operating personnel because they could be fully automatic in responding to the control signals transmitted from the master station 4. The operator within the vehicle 16 responds to firing information computed such as by a soldier 24 giving firing commands to the weapon 12. Figure 3 shows that by using at least three remote actuators, radio waves 26 transmitted therefrom sequentially sweep across a common area to define an elliptical area which more realistically defines the shape of the geographical zones affected by the fire support replicted by the present invention. The master station 4 is shown communicating by electromagnetic waves 28, (e.g. radio waves) with three remote actuators 30,32,34, which represent the remote actuators in the vehicles 18, 20, 22, respectively. Through this communication, the actuator 34 propagates a first actuation signal at a time T, followed by an actuation signal from the remote actuator 32 at time T + 1, and a third actuation signal from the actuator 30 at time T + 2. The master station 4 shown in Figure 4 includes a radio 36 for receiving data, such as from the soldier 24 at the fire direction centre controlling the weapon 12 shown in Figure 2. The data, which can be conveyed by voice or by digital signals, includes at least the type of ammunition whose firing from the weapon 12 is to be replicated and the co-ordinates of the target area 14. The radio 36 is connected to a processor 38 through a suitable interface device 40. The processor 38 is any suitable computing mechanism, such as a microcomputer of any suitable type and having an associated data storage device 42, capable of storing the information needed by the processsor 38. In response to the data input through the radio 36 and the data stored in the data storage 42, the processor 38 generates suitably encoded control signals transmitted as encoded radio waves by a radio 46, which can be the same as or different from the radio 36, connected through an interface 44. Also associated with the processor 38 are keyboard 48, a display screen 50 and a printer 52 of types as known to the art. The elements 36,38,40,42,44,46,48,50,52 are mounted within the vehicle 16 to provide a compact, unified, transportable master station. To power these elements, the power from the veicle 16, mains power, portable generators, or batteries can be used. Such power is connected to a suitable power distribution unit 54 for driving a power supply 56 providing power signals at the appropriate voltage levels for use by the elements 36-52. The elements 36-52 are preferably of commercially available type. The processors 38 is programmed in any suitable manner for correlating the input data for computing the resulting control signals, which are further developed based upon the selected target area known through the data entered via the radio 36. Thus, the master station provides the planning, co-ordinating, timing and actuator selecting functions for the overall system. Once these functions are performed and the control signals generated, they are transmitted, preferably at a power not greater than ten watts to give a range from the master station of approximately 32 kilometres. The construction of one of the remote actuators 30,32,34 is shown in Figure 5, to include a suitable radio frequency receiver 58, which receives the control signals from the master station 4 and provides them to a processor/encoder 60 through an interface 62. A standardised timing source 64 allows each processor/encoder 60 to generate an actuating signal, for transmission through a transmitter 66, in response to both the timing signal from the timing source 64 and the timing and target information (type of munition) conveyed to the remote actuator from the master station 4. Power for the remote actuator is provided from a generator 68 through a power distribution circuit 70 or from any other suitable source, such as battery or solar power so that the actuator can be located in a remote, isolated location and left unattended to operate automatically in response to the control signals from the master station 4. As shown in Figure 6, the remote actuator includes a single antenna 72 switchably connectable to either a receiver 74 or the output of a band pass filter 76, which forms part of the transmitter 66. The receiver 74 is the same type used in the indicator units 8, and provides its signal to a decoder/timing circuit 78, which is controlled by a microprocessor controller 80 to provide a signal to an encoder/timing circuit 82 providing an output which is modulated through a modulator 84 by a radio frequency from a radio frequency source 86. The modulated signal is amplified by an amplifier 88 before being output through the band pass filter 76. To enable the remote actuator to be controlled by an operator who might, but need not be, located thereat, a keyboard 90 and a display 92 are also shown in Figure 6 as being associated with the microprocessor controller 80, which also includes an interface input 94 for receiving external control signals, such as from the global positioning system which can be utilised to locate the remote actuator as it is moved from place to place. Preferably the remote actuator is of a size which can fit in a portable carrying case and is less than 6.8 kg in weight. The electronics should be selected so that they can be energised by any suitable power source, such as the battery within the vehicle in which it can be mounted. To conserve such power, the transmitter power output should also be kept low, such as to ten watts. The carrying case should also accommodate the antenna which can have a magnetic mount or a fixed mount for easy assembly when the remote actuator is positioned at its remote location. Furthermore, the remote actuators and indicator units, are preferably implemented with the surface acoustic wave technology available through Motorola, Inc to enhance the operation of the present invention. The preferred embodiment of one of the indicator units 8 is shown in Figure 7. Each unit includes a receiver 96 which provides a signal to a detector/decoder 98, which communicates with the MILES disabling unit through an interface 100. These elements are powered by a battery 102. The elements 96,98,100 shown in detailed block diagram form in Figure 8 are types as known to the art with the surface acoustic wave (SAW) device 104 and the XN device 106 being members of the known Motorola, Inc 68000 series of chips. A timing/decoder logic circuit 108 can be switchably, or otherwise, variable by a type code plug 110 to specify the nature of the object with which the indicator is associated. For example, the type code plug 110 can be set to define the object as a person, as a truck or any of a plurality of other objects. When the timing/decoder logic circuit 108 determines for that selected type of object that it has been hit by the replicated ammunition, it generates a hit control signal which in the preferred embodiment causes the MILES disabling unit to disable the weapon of the object. If the object is not hit, a near miss signal is provided so that the object is advised it has been in the affected zone but not hit. The disabling unit of the MILES system is of a known type, the interface provided through the timing/decoder logic circuit 108 provides the needed inputs to activate the disabling unit of the MILES system carried on each object. A 100-meghertz reference clock 111 permits a 3 metre resolution within the affected zone. Each indicator unit is contemplated to be constructed in a compact size at a weight of less than 450 gm so that it can be easily carried by personnel without affecting their performance during a training exercise. Since there are to be many indictor units used throughout the target area, and such use is to be in the field, the indicator units should also be durably constructed, but of a relatively low cost. Power may be provided by two C-size lithium batteries and the antenna may be a monopole either attached to the indicator unit or sewn in as part of the harness used with the MILES disabling unit. Of particular importance, however, in selecting specific components of the apparatus are the frequency at which it is to operate and signal-to-noise considerations. Advantageously the frequency should provide relatively accurate electronic line-of-sight propagation and should also be capable of penetrating foliage and otherwise having low losses within the environment in which it is to be used. However, it should provide a degree of battlefield realism by exhibiting some propagation anomalies. The frequency should have a wide bandwidth associated therewith for providing high resolution and multi-path protection. While achieving these technical requirements, the frequncy selection should also permit the indicator units to be constructed at a low cost with readily available, low cost devices. Furthermore, the selected frequency must be compatible with others who are using the same frequency band. We have determined that one suitable range of frequency is within the range between 100 to 1000 megahertz. One analysis indicates that the specific frequency of approximately 915 megahertz, with a 20-megahertz bandwidth, meets the aforementioned technical and cost requirements. Furthermore, this specific frequency and bandwidth can be used for positioning-type systems, and they allow for ten watts to be used without special authorisation. This band is used by industrial, scientific and medical equipment, but use of coding in the present invention can be protected from incidental interference with these other uses. Furthermore, the low power and duty cycling operation which can be implemented prevent or reduce the chance of interference with these other uses. The importance of the signal-to-noise considerations is that a relatively high level of noise can be encountered in the replicated battlefield environments. Therefore, a suitable signal-to-noise ratio should be designed into the system approximately 40 dB, but minimum ratios of approximately 20 dB may also be acceptable. To further preclude noise interference, actuations of the devices are designed to occur at the leading edge of the control signals at a threshold suitably above the anticipated noise level so that actuations occur before otherwise interferring multi-path responses occur and not as a result of noise. Additionally it is contemplated that further elements can be incorporated with the master station 4, the remote actuators 6 and the indicator units 8 to provide realism of the battlefield while maintaining safety to personnel and equipment. For example, visual simulations can be effected through the use of smoke cannisters, flashing lights and small smoke cartridges. Audible simulation of explosions can be created with electro-acoustic transducers, compressed air, small charges, or lightweight headsets to which simulated sounds of explosions can be provided. Sound synthesis techniques can be used with the indicator units 8, and the volume can be varied as a function of the distance the specific object is from the computed impact location. With reference to Figures 9A-9D, different modes of operation will be described. In Figure 9A, the normal mode is illustrated, in which a master station 112 communicates directly with each of three remote actuators 114,116,118, which in turn each transmit an actuating signal to be received by an indicator unit 120 located within the affected zone of the target area. In a relay mode of operation illustrated in Figure 9B, a master station 122 communicates directly only with a remote actuator 124, which then provides controlling communications to two other remote actuators 126,128. Each of the actuators 124,126,128 then generates its own actuating signal to an indicator unit 130. A multiple relay mode is illustrated in Figure 9C. A master station 132 communicates with two intermediate remote actuators 134 and 136. The actuator 134 then provides controlling communication to remote actuators 138,140, which in turn communicate with an indicator unit 142. The actuator 136 communicates with a remote actuator 144 which is the third actuator in communication with the indicator unit 142. Figure 9D depicts a polling/calibration mode in which the indicated signals are conveyed between a master station 146 and remote actuators 148,150,152. One use of this mode is to ensure that all the standardised timing sources 64 within the remote actuators are synchronised. Referring to Figures 2, 10, 11A-C and 12A-B, the operation will be described. As shown in Figure 10, initially a forward observer calls in fire on co-ordinates X, Y, which designate the target area 14. The information from the forward observer is processed at the firing unit, such as by the person 24, and the decision is made to fire the weapon 12. Once the information has been processed and the decision made to fire the weapon 12, the information as to the type and quantity of ammunition and the location of the target area to be fired upon is conveyed to the weapon 12. This same information is received through a communication link, e.g. by a person in the vehicle 16 receiving verbal communications over the radio 36 and then inputting the information into the processor 38 or by direct communication of digital signals into the radio 36 and on into the processor 38. When the processor 38 receives the information through the communication link (and any other input, examples of which are designated in Figure 10), the processor 38 determines the optimum remote actuators for defining the affected zone through the radio waves sequentially transmitted from the selected actuators. The processor 38 also calculates the timing sequence of the selected remote actuators. The selection of the actuators and the timing sequence is shown in Figure 10 as taking approximately 20 milliseconds of processing time and once this information has been determined, the processor 38 enters a wait or delay mode. The operator in the vehicle 16 continues to monitor the firing sequence of the weapon 12 so that when the fire command is given, the operator can actuate the processor 38 to commence its transmission sequence at a suitable time accounting for the computed time of the replicated flight of the ammunition (which, of course, is not actually fired into the selected target area). At the appropriate time, the processor 38 transmits its control signals to the remote actuators, which in turn sequentially transmit their actuating signals to the indicator units 8 for activation at the projected time of impact. By using at least three remote actuators to send actuating signals to the target area, a substantially elliptical zone will be commonly covered at different times by each of the remote actuator's signals during its respective transmisstion time. This zone is a realistic replication of the zone that would actually have been covered by the selected ammunition had it actually been fired into the target area. Such a replicated zone would not be defined by only one or two remote actuators. In actuating the indicator units 8, the apparatus selects which ones will constitute the total number of "kill" or "hit" items, which number is based upon the Joint Munitions Effectiveness Manuals. For those indicators which generate a "hit" signal, the indicator unit provides a suitable signal to the interfaced MILES disable unit to disable the weapon associated with the "hit" object. Visual and audible signals can also be simultaneously provided so that the individual objects are immediately notified of their status and so that observers can make the necessary damage assessment and call for additional replicated fire if required. The sequential timing sequences for the different modes of operation are shown in Figures 11A-11C. For example, in Figure 11A, it takes approximately ten milliseconds in the preferred embodiment for the master station to transmit the information to the actuators. This corresponds to the "transmit to actuators" block shown in Figure 10. Figure 11A also shows the sequential transmission allotted to each of five remote actuators. This corresponds to the "transmit to appliques" block shown in Figure 10. Figures 11B and 11C are self-explanatory. The message structures within the transmissions between the master station and the remote actuators and between the remote actuators and the indicator units are shown in Figures 12A and 12B, respectively. Figure 12A shows the master station to actuator message structure used during the approximately ten millisecond communication time between the master station and the actuators indicated in Figures 10 and 11A-C. The message structure includes identification for each actuator, and corresponding target (munition code) and time data used by the remote actuators in generating the actuating signals. Figure 12B shows that the principal portion of the actuator to applique message is the targeting code which activates a logic circuit within the decoder 108 resulting in a signal of a "hit" or a "near miss". Information conveyed by each remote actuator can be different so that the indicator units can be sequentially instructed, whereby an indicator unit will "know" it is not within the affected zone if the entire sequence of instructions is note received in the proper order. Looked at another way, in operation the master station generates the master control signal in response to the type and quantity (e.g. number of rounds) of ammunition whose fire is to be replicated and in response to the co-ordinates of the selected target area. Part of the master control signal is coded to instruct the remote actuators on when and how long to emit their respective pulses, which define the actuating signals generated by the remote actuators. When the pulses are to commence is based on the respective locations of the actuators to the target area; the length of time is based on the type of ammunition, and it determines the size of the affected zone in the target area (i.e. longer duration pulses from the actuators define a larger elliptical area than do shorter duration pulses). Still another part of the master control signal instructs the remote actuators on how many of the pulses are to be emitted from the remote actuators; this is based on the quantity (e.g. number of rounds) of ammunition. A further part of the master control signal is the identification of the remote actuators that are to be used in communicating to the target area to define the affected zone; this is based on the location information received by the master station. Because many remote actuators can be placed throughout a wide area, the optimum ones of these actuators for covering the specific target location are selected and instructed by the master control station as just described. Having received the foregoing information, the remote actuators generate the required pulses at the appropriate times, as synchronised from the standard timing sources within each actuator. Each pertinent remote actuator encodes its respective pulse or pulses with a preamble identifying the remote actuator and with targeting code information identifying the type of ammunition "fired" into the target area. Thus, each remote actuator sends the same targeting code information to the target area. In the contemplated specific embodiment, any one of 128 different types of munitions can be encoded in the actual signal. The actuating signals from the pertinent remote actuators sweep across the target area as they are generated, thereby defining the substantially elliptical zone. It is contemplated that within this zone, the appliques will receive and respond to actuating signals received within a timing window, such as from three consecutive remote actuators; if an applique does not, it is not affected. That is, if only three remote actuators are designated in the timing sequence A₁, A₂, A₃ by the master control station to be within the window, an applique will not respond unless it receives the actuating signals, in order, from A₁, A₂, A₃. If five actuators sequenced as A₁, A₂, A₃, A₄, A₅ are designated, for example, then an applique responsive to three timing pulses within the window will respond only if it receives in order the signals from A₁, A₂, A₃ or from A₂, A₃, A₄ or from A₃, A₄, A₅. Assuming an applique receives the appropriate actuating signals, this activates a logic circuit such as may be implemented by a suitably programmed eraseable programmable read only memory (EPROM). In the specific embodiment, this programming is based on the known percentages set forth in the Joint Minitions Effectiveness Manuals; however, other information can be used in programming or constructing the logic circuit. Whatever basic information is used, the purpose of the contemplated specific embodiment of the appliques is to create an output based on the probabilities of the object carrying the applique being hit by the type of ammunition "fired" into the target area. A flow chart or block diagram of this logic circuit is illustrated in Figure 13. This figure shows an applique has been set to be a tank. Five types of ammunition (HE, DPICM, CUHD, SADARM, MINES) are shown, and the probabilities for each are listed. These probabilities are implemented within the programming or circuitry. Finally, the MILES sensors/disabling unit is indicated as capable of displaying a 'near miss" or a "kill". For example, if a high explosive (HE) round is "fired", there is a 10% probability that the tank will be affected by this. Therefore, approximately 10% of the time (over a long term) the logic circuit will continue on, selecting whether the tank has been a "hit" or a "near miss". When this ultimate decision has been made a suitable signal is provided to the MILES system to display "kill" or "near miss". Because the logic circuit within each applique located in the affected zone operates independently of the other appliques' logic circuits, the simulated effect at any one time is random. For example, all of the logic circuits may independently coincide on all "hits" or on all "near misses" to show that everything has been killed or that none have, respectively. The combinations between these extremes are also possible. From the foregoing, it is apparent that the specific embodiment implements the "hit" or "miss" decision-making at the target area. This configuration permits the same type of appliques to be used throughout, and it simplifies the control and actuating signals in that they do not need to specifically address individual appliques to inform them that they have been hit or missed. Furthermore, this obviates the necessity of storing larger data bases which would likely be needed if the "hit" and "miss" decisions were made upstream. In summary, the preferred embodiment of the present invention utilises a single frequency, time-division multiplex transmission technique implemented through the same type of ten-watt transmitters in the master station and the remote actuators. The transmissions provide control signals which ultimately actuate indicator units designating which objects within an affected zone have been "hit" and which have been "near misses". The technique uses a suitable coding for providing good resolution and multipath performance. A single master station controls all of the system timing and external interfaces to select optimally located remote actuators appropriately to cover the target area with radio waves realistically to define the affected zone. The system can replicate fire to a plurality of targeting points each second and can simulate the effect of the replicated fire on multiple targeted objects so that multiple actions which can occur substantially simulanteously on a battlefield can be realistically simulated. The system can be operated in a calibration mode to ensure that all remote actuators are properly operating from a standard timing source contained within each remote actuator. The system can also be operated in a relay mode so that a target area covered by remote actuators which are not in the electronic line of sight of the master station can be controlled by intermediate or relaying remote actuators which are in electronic line-of-sight communication with the master station. Furthermore, the present invention complements the MILES system by utilising low cost, lightweight indicator units interfaced with the portions of the MILES system mounted on the personnel and equipment within the target area. The remote actuators, which communicate directly with the indicator units, are portable and can be located in isolated areas to operate from vehicular batteries or other power sources. The remote actuators can be non-stationary with instantaneous locations being determined through an interface with the global positioning system or other position determining device. The system can be constructed of conventional electronics, but selected and assembled to operate at an appropriate frequency and to provide excellent signal-to-noise ratios for reliable operation even in high-noise environments such as a replicated battlefield. The system can also incorporate known surface-acoustic-wave devices to provide simple, effective signal processing; however, any suitable timing device can be used.

Claims: A portable indicator apparatus for detecting when an object at a target area has been hit by replicated indirect ammunition fire, comprising radio frequency receiver means (96), attached to the object, for receiving radio frequency actuating signals to be emitted from a plurality of remote actuators; and means (100), responsive to decoder means (98), for signifying when the object has been hit by the replicated ammunition fire, characterised in that the decoder means (98) includes means for programming said apparatus with a plurality of probabilities for a predetermined type of object to be hit, wherein each of the probabilities is assigned to a respective type of replicated indirect ammunition fire, so that in response to receiving in order said radio frequency actuating signals, which are encoded to designate at least one type of replicated indirect ammunition fire, said means (98) determines whether the actuating signals designate that the object has been hit. Apparatus according to claim 1, characterised in that said decoder means (98) includes means for variably specifying the specific type of object to which a respective one of said indicator apparatus is attached. Apparatus according to claim 1 or 2, characterised in that said means for signifying includes disabling means for electronically disabling a weapon associated with the object when the object has been hit by replicated direct ammunition fire; and interface means (100) for interfacing said decoder means (98) and said disabling means so that said disabling means electronically disables the weapon associated with the object in response to said decoder means determining the object has been hit by the replicated indirect ammunition fire. Apparatus according to claim 3, characterised in that the direct ammunition fire is replicated by a laser beam.

Inventors: DOERFEL, STEPHEN, POKORNY, ANTHONY G., RUBIN, HOWARD H.
Applicants: L B & M ASSOCIATES, INC.
Application year: 1986
Main classification: F41G3
IPC codes: G01S5, F41G3