CA2576754A1 - Method and apparatus for detecting and indicating battlefield threats - Google Patents
Method and apparatus for detecting and indicating battlefield threats Download PDFInfo
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- CA2576754A1 CA2576754A1 CA 2576754 CA2576754A CA2576754A1 CA 2576754 A1 CA2576754 A1 CA 2576754A1 CA 2576754 CA2576754 CA 2576754 CA 2576754 A CA2576754 A CA 2576754A CA 2576754 A1 CA2576754 A1 CA 2576754A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
- G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
- G01S3/14—Systems for determining direction or deviation from predetermined direction
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- Radar, Positioning & Navigation (AREA)
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- Radar Systems Or Details Thereof (AREA)
- Position Fixing By Use Of Radio Waves (AREA)
Abstract
A method for detecting threats to security forces by using a combination of acoustic and radio direction finders and for indicating those threats using a laser designator, audio warning, on-screen display, and a laser range finder. The apparatus comprises the mast, which houses the sensors and laser indicators, and the main system, which houses the bulk of the electronics and the audio and video outputs.
Description
METHOD AND APPARATUS FOR DETECTING
AND INDICATING BATTLEFIELD THREATS
Field of the Invention This invention is related to methods of detecting and direction finding radio signals and small arms fire. It is also related to providing type, range, and bearing information of the detected threats.
Description of Related Art Radio direction finding equipment is commercially available and has been in use for decades. Such equipment is capable of giving a bearing to the transmitter dependant upon the type of modulation and frequency used. By having two or more radio direction finders operating, or by moving one radio direction finder, it is possible to generate multiple bearings which "triangulate" or give an approximate location of the transmitter. Military forces routinely use this method of locating transmitters in an effort to determine the general location and movement patterns of opposing forces. This method of radio direction finding is not currently used, however, to detect threats to individual soldiers or vehicles. Radio direction finders are also not currently used to detect transmissions consistent with attempts to initiate radio-controlled improvised explosive devices (IED).
Acoustic direction finding equipment has also been in use for decades, and very effective systems for determining the location of small arms fire have recently been produced. These systems seek to give an accurate bearing to the source of small arms fire, which can be very difficult to determine, especially in urban areas.
Laser range finders use a laser to determine the exact distance, or range, to a specific point. They are in common use with military forces as determining accurate range is a vital factor in bringing effective fire (direct or indirect) onto a target.
Laser designators/pointers have a variety of military uses, most applicably as a weapons sight where a red dot is used to indicate where the bullet will strike.
Laser designators or pointers are not currently used as a method of visually indicating threats.
Summary of the Invention A method for detecting threats to security forces is provided, using a combination of acoustic and radio direction finders, spectrum analysis to locate a threat and a laser pointer, audio warning, on-screen display, and a laser range finder to visually mark the location of the threat, both on-screen, and at the actual site of the threat.
The apparatus comprises a mast, which houses the antenna, sensors and laser indicators, and the main system, which houses the bulk of the electronics and the audio and video outputs.
In a broad aspect, the present invention relates to a device for locating the source of an electromagnetic radiation (emr) transmission including: a direction finding antenna for detecting said emr transmission and establishing, as an output signal, the direction in at least the horizontal x=y, plane, from which said transmission emanates; a radio signal receiver for receiving said emr transmissions and establishing, as an output signal, the nature of said transmission; a controller for receiving the output signals from said direction finding antenna and radio signal receiver , establishing the threat level of said emr transmission, and outputting a signal to a user discernable output device, to indicate the nature and threat level of the emr transmission; and a signal to a 360 positionable laser pointer to provide a visible line pointing in the direction of the emr transmission.
In drawings that illustrate the present invention by way of example:
Figure 1 is a perspective/schematic of the multi-threat indication system (MTIS) of the present invention.
Figure 2 is a photograph showing the system of the present invention identifying and pointing to a threat source.
Figure 3 is a diagram showing the arrangement and function of a Doppler shift direction finding antenna.
Figure 4 is a block diagram showing the major components of the MTIS
system of the present invention.
Figure 5 is a block diagram of the main board of the MTIS of the present invention.
Figure 6 is a block diagram of input devices_ and input interface for the MTIS of the present invention.
Figure 7 comprises block and display diagrams for the output interface and output devices of the MTIS of the present invention.
Figure 8 is a block diagram of the Mast assembly of the MTIS of the present invention.
Figure 9 is a perspective/schematic of the horizontal and vertical polarized Doppler antenna arrays of the MTIS of the present invention.
Figure 10 is a block diagram and perspective of the laser sub-assembly of the MTIS of the present invention.
Figure 11 is a diagram showing location of stepper motor assembly in the mast assembly of the MTIS of the present invention.
Figure 12 is a schematic of the horizontal stepper motor assembly and function.
Figure 13 is a schematic of the vertical stepper motor assembly and function.
Figure 14 is a pair of block diagrams for the horizontal and vertical mast sub-system electronics modules of the MTIS of the present invention.
Figure 15 is a block diagram of the mast power module.
Figure 16 is a diagram of a moving vehicle or more than one vehicle employing the MTIS of the present invention to locate and identify a threat.
Figure 17 is a front view of a MTIS LCD display layout.
Figure 18 is a front view of an LED directional and bearing display.
Detailed Description of the Invention The invention as illustrated in Figure 1 consists of a suite of sensors built into a mast, and a series of output devices designed to show the type and.location of the threat.
The mast is mounted externally on a vehicle, at a facility such as a forward operating base, or carried on the back of a soldier in a pack device. The mast's primary purpose is to house and protect the sensor suite and laser pointer.' The sensor suite consists of a laser range finder, an acoustic direction finder such as that described in US Patent No. 6178141, and a radio direction finder antenna array. The inputs from these sensors are fed into a computer housed inside the vehicle, base location, or soldiers pack, where software is used to determine if a threat exists and, if so, the bearing and distance to that threat.
The threats detectable by the sensor suite are: small arms fire, active hostile communications devices indicating possible ambush or other activity, and attempts to initiate improvised explosive devices using radio devices such as cell phones, walkie-talkies, garage door openers, etc.
Once a threat has been identified, the invention uses a stabilised high-power laser pointer to indicate the direction of the threat, the laser range finder to determine range to the threat, and may provide a unique audio warning to identify the type of threat detected. It also displays all known information about the threat on a screen. An example of a visual threat identification is shown in Figure 2, wherein the laser pointers on adjacent vehicles in a convoy have each located an IED
threat source (a garage door opener signal source in an inappropriate location) Each vehicle mounted system will independently point to the threat, and the point of intersection of the laser be the source of the threat.
Doppler Shift Direction Finding - Background The direction finding (DF) capability of the MTIS is derived from the use of Doppler shift, however Time Difference of Arrival (TDOA) systems are applicable also.
The Doppler system is capable of detecting Frequency Modulated (FM), Amplitude Modulated (AM), Carrier Wave (CW) and Single Side Band (SSB) signals. Four vertical antennas are arranged at known points around the perimeter of a circle and the receiver is sequentially switched to each antenna in turn. The result is a single virtual antenna that revolves in a circle. The resulting Doppler shift causes the received signal to be Doppler modulated with a sine wave, whose frequency is equal to the rotation frequency of the virtual antenna.
The shift to the different antennas is performed by fast switching diodes located at the base of the antenna.
Audio filtering is required to remove any voice modulation and construct a Doppler sine wave. The Doppler sine wave has two zero-crossing points which occur when the virtual antenna is closest to the signal source and farthest from the signal source. The closest signal source zero crossing always occurs at the end of the positive half cycle or falling edge zero crossing point, as shown in Figure 3.
Doppler modulation is a form of frequency modulation (FM) caused by relative motion between the transmitter and the receiver. Because it is a form of frequency modulation, an FM receiver is required to detect it.
The system of the present invention can be fitted with two Doppler antenna arrays to detect direction and elevation of the incoming signal. To achieve this, one array is horizontally polarized and the other vertically polarized, as shown in Figure 1, and schematically in Figure 4.
AND INDICATING BATTLEFIELD THREATS
Field of the Invention This invention is related to methods of detecting and direction finding radio signals and small arms fire. It is also related to providing type, range, and bearing information of the detected threats.
Description of Related Art Radio direction finding equipment is commercially available and has been in use for decades. Such equipment is capable of giving a bearing to the transmitter dependant upon the type of modulation and frequency used. By having two or more radio direction finders operating, or by moving one radio direction finder, it is possible to generate multiple bearings which "triangulate" or give an approximate location of the transmitter. Military forces routinely use this method of locating transmitters in an effort to determine the general location and movement patterns of opposing forces. This method of radio direction finding is not currently used, however, to detect threats to individual soldiers or vehicles. Radio direction finders are also not currently used to detect transmissions consistent with attempts to initiate radio-controlled improvised explosive devices (IED).
Acoustic direction finding equipment has also been in use for decades, and very effective systems for determining the location of small arms fire have recently been produced. These systems seek to give an accurate bearing to the source of small arms fire, which can be very difficult to determine, especially in urban areas.
Laser range finders use a laser to determine the exact distance, or range, to a specific point. They are in common use with military forces as determining accurate range is a vital factor in bringing effective fire (direct or indirect) onto a target.
Laser designators/pointers have a variety of military uses, most applicably as a weapons sight where a red dot is used to indicate where the bullet will strike.
Laser designators or pointers are not currently used as a method of visually indicating threats.
Summary of the Invention A method for detecting threats to security forces is provided, using a combination of acoustic and radio direction finders, spectrum analysis to locate a threat and a laser pointer, audio warning, on-screen display, and a laser range finder to visually mark the location of the threat, both on-screen, and at the actual site of the threat.
The apparatus comprises a mast, which houses the antenna, sensors and laser indicators, and the main system, which houses the bulk of the electronics and the audio and video outputs.
In a broad aspect, the present invention relates to a device for locating the source of an electromagnetic radiation (emr) transmission including: a direction finding antenna for detecting said emr transmission and establishing, as an output signal, the direction in at least the horizontal x=y, plane, from which said transmission emanates; a radio signal receiver for receiving said emr transmissions and establishing, as an output signal, the nature of said transmission; a controller for receiving the output signals from said direction finding antenna and radio signal receiver , establishing the threat level of said emr transmission, and outputting a signal to a user discernable output device, to indicate the nature and threat level of the emr transmission; and a signal to a 360 positionable laser pointer to provide a visible line pointing in the direction of the emr transmission.
In drawings that illustrate the present invention by way of example:
Figure 1 is a perspective/schematic of the multi-threat indication system (MTIS) of the present invention.
Figure 2 is a photograph showing the system of the present invention identifying and pointing to a threat source.
Figure 3 is a diagram showing the arrangement and function of a Doppler shift direction finding antenna.
Figure 4 is a block diagram showing the major components of the MTIS
system of the present invention.
Figure 5 is a block diagram of the main board of the MTIS of the present invention.
Figure 6 is a block diagram of input devices_ and input interface for the MTIS of the present invention.
Figure 7 comprises block and display diagrams for the output interface and output devices of the MTIS of the present invention.
Figure 8 is a block diagram of the Mast assembly of the MTIS of the present invention.
Figure 9 is a perspective/schematic of the horizontal and vertical polarized Doppler antenna arrays of the MTIS of the present invention.
Figure 10 is a block diagram and perspective of the laser sub-assembly of the MTIS of the present invention.
Figure 11 is a diagram showing location of stepper motor assembly in the mast assembly of the MTIS of the present invention.
Figure 12 is a schematic of the horizontal stepper motor assembly and function.
Figure 13 is a schematic of the vertical stepper motor assembly and function.
Figure 14 is a pair of block diagrams for the horizontal and vertical mast sub-system electronics modules of the MTIS of the present invention.
Figure 15 is a block diagram of the mast power module.
Figure 16 is a diagram of a moving vehicle or more than one vehicle employing the MTIS of the present invention to locate and identify a threat.
Figure 17 is a front view of a MTIS LCD display layout.
Figure 18 is a front view of an LED directional and bearing display.
Detailed Description of the Invention The invention as illustrated in Figure 1 consists of a suite of sensors built into a mast, and a series of output devices designed to show the type and.location of the threat.
The mast is mounted externally on a vehicle, at a facility such as a forward operating base, or carried on the back of a soldier in a pack device. The mast's primary purpose is to house and protect the sensor suite and laser pointer.' The sensor suite consists of a laser range finder, an acoustic direction finder such as that described in US Patent No. 6178141, and a radio direction finder antenna array. The inputs from these sensors are fed into a computer housed inside the vehicle, base location, or soldiers pack, where software is used to determine if a threat exists and, if so, the bearing and distance to that threat.
The threats detectable by the sensor suite are: small arms fire, active hostile communications devices indicating possible ambush or other activity, and attempts to initiate improvised explosive devices using radio devices such as cell phones, walkie-talkies, garage door openers, etc.
Once a threat has been identified, the invention uses a stabilised high-power laser pointer to indicate the direction of the threat, the laser range finder to determine range to the threat, and may provide a unique audio warning to identify the type of threat detected. It also displays all known information about the threat on a screen. An example of a visual threat identification is shown in Figure 2, wherein the laser pointers on adjacent vehicles in a convoy have each located an IED
threat source (a garage door opener signal source in an inappropriate location) Each vehicle mounted system will independently point to the threat, and the point of intersection of the laser be the source of the threat.
Doppler Shift Direction Finding - Background The direction finding (DF) capability of the MTIS is derived from the use of Doppler shift, however Time Difference of Arrival (TDOA) systems are applicable also.
The Doppler system is capable of detecting Frequency Modulated (FM), Amplitude Modulated (AM), Carrier Wave (CW) and Single Side Band (SSB) signals. Four vertical antennas are arranged at known points around the perimeter of a circle and the receiver is sequentially switched to each antenna in turn. The result is a single virtual antenna that revolves in a circle. The resulting Doppler shift causes the received signal to be Doppler modulated with a sine wave, whose frequency is equal to the rotation frequency of the virtual antenna.
The shift to the different antennas is performed by fast switching diodes located at the base of the antenna.
Audio filtering is required to remove any voice modulation and construct a Doppler sine wave. The Doppler sine wave has two zero-crossing points which occur when the virtual antenna is closest to the signal source and farthest from the signal source. The closest signal source zero crossing always occurs at the end of the positive half cycle or falling edge zero crossing point, as shown in Figure 3.
Doppler modulation is a form of frequency modulation (FM) caused by relative motion between the transmitter and the receiver. Because it is a form of frequency modulation, an FM receiver is required to detect it.
The system of the present invention can be fitted with two Doppler antenna arrays to detect direction and elevation of the incoming signal. To achieve this, one array is horizontally polarized and the other vertically polarized, as shown in Figure 1, and schematically in Figure 4.
Logic and Processing System Referring now to Figure 5, the logic and processing system processes the receiver output audio and sends the directional information to the output interface using an Agrello Direction Finding format. This system includes the antenna control that performs the electrical switching operation for the antennas and combines the resulting signals into a single signal to be connected to the radio receiver's antenna input. The processing unit will also translate DF messages into the military (Mils) bearing units of 0-6400 if that is required. (The output devices will typically perform their own unit transformations.) The Logic and Processing System includes a microprocessor and memory component that analyzes the incoming signal to determine the type of threat against an internal database. The software, firmware and database are able to be changed through the Input Interface to allow the unit to be updated regularly as new threat information becomes available and software changes are made.
Agrello Format Messages - Background The received bearings are translated to Agrello format messages by the Logic and Processing Board. This format is %xxx/n <cr>. The following table summarizes the format.
Agrello Format Messages - Background The received bearings are translated to Agrello format messages by the Logic and Processing Board. This format is %xxx/n <cr>. The following table summarizes the format.
Symbol Meaning /o Separator between essa es.
xx 3earing in degrees.
)-359.
n rhe "n" is the elative strength of he signal from 1-7.
cr> arria e Return Input Interface The input interface has three main functions. These are:
1. Interface to the Doppler Antenna 2. Interface to the radio receiver antenna and audio connectors; and 3. Interface to another computer or memory device for software/firmware and database updates.
Output Interface The output interface (see Figure 7) physically connects the logic and processing system to the various output devices that are able to be used with the MTIS
unit.
The basic equipment includes the Audio Warning device and the LED Directional Display. Additional equipment can also be added for Graphical User Interfaces and other indicators.
xx 3earing in degrees.
)-359.
n rhe "n" is the elative strength of he signal from 1-7.
cr> arria e Return Input Interface The input interface has three main functions. These are:
1. Interface to the Doppler Antenna 2. Interface to the radio receiver antenna and audio connectors; and 3. Interface to another computer or memory device for software/firmware and database updates.
Output Interface The output interface (see Figure 7) physically connects the logic and processing system to the various output devices that are able to be used with the MTIS
unit.
The basic equipment includes the Audio Warning device and the LED Directional Display. Additional equipment can also be added for Graphical User Interfaces and other indicators.
Antenna Array The antenna array module (see Figure 9), that is part of the mast assembly (schematic of Figure 8) contains two antenna systems, each containing a minimum of four antenna elements. One antenna is horizontally polarized, the other vertically. The ground plane of the antenna array contains diodes that allow each antenna element to be switched on and off. These diodes are controlled by the antenna control electronics contained on the Logic and Processing System.
Each antenna element is a'/4 wave whip antenna. They are typically mounted between .22 and .25 wavelength apart in a square pattern, on a ground plane.
Laser Range Finder The laser range finder part of the laser sub-assembly (see Figure 10) is a device which uses a laser beam in order to determine the distance to a reflective object.
It measures the distance to an object by measuring the time it takes for the laser pulse to be returned to the laser range finding equipment. The laser range finder in the MTIS mast is activated once a signal is detected. The MTIS stepper motor assembly will rotate the laser range finder to the correct bearing and the secondary motor in the laser assembly will raise or lower the lasers if the horizontally polarized antenna array is able to determine the relative elevation of the target. If the circumstances permit, a distance to the target will be determined and the information processed to the output devices attached to the MTIS
mast. If an elevation cannot be determined, the laser will remain horizontal.
Laser Designator The laser designator is a device which uses a laser beam in order to give a visual indication of the threat direction. The MTIS stepper motor assembly (see Figure 11) will rotate the laser to the correct bearing and the secondary motor in the laser assembly will raise or lower the laser if the horizontally polarized antenna array is able to determine the relative elevation of the target. The target area will then be indicated by the visual laser end point for engagement. If an elevation cannot be determined, the laser will remain horizontal.
Stepper Motor Assembly There are two parts to the Stepper Motor Assembly. The first is a stepper motor shown in Figure 12, that rotates the laser sub-assembly 360 degrees on the horizontal plane to the bearing detected by the (Vertical) Doppler antenna array and associated electronics. The second part shown in Figure 13 is a stepper motor that raises or lowers the laser sub-assembly on the vertical access to indicate relative elevation of the target.
A
microcontroller is used to translate the Agrello format bearing messages to the correct motor step to point to the lasers to the appropriate bearing. The Vertical Stepper Motor driver will receive Agrello format messages, however they are limited to 0-180 degrees (vertical).
Mast Sub-system Electronics Module This module (Figure 14) contains the Stepper motor microcontrollers, and delivers the required power to the mast systems, including the Stepper Motor Assembly and Laser Sub-assembly.
This module contains the batteries required to drive the Stepper Motors, Lasers and the Mast Sub-system Electronics Modules.
Input Devices Radio Receivers The FM radio receivers are used to determine the operating frequency for the direction finding unit. They are connected to the Antenna Arrays for horizontal and vertical polarization. The receiver speaker output is connected to the main board audio input.
The Doppler modulation results in an audio tone that is detected and. fed to the speaker of the MTIS display unit.
The radio receivers are typically set to scan the appropriate frequency spectrum and pause on that frequency if a signal is intercepted. Resumption of the scan can be manual or automatic.
GPS
The GPS input is optional, however the GPS data can be combined with the DF
Agrello format messages for plotting onto a map display. For example:
If the user of the MTIS is moving, the GPS and Doppler data can be combined to give a more accurate fix on the transmitted signal with one MTIS. As lines of intersection are made, the most likely position will be processed in real-time and the stepper motor will adjust the laser sub-assembly to the new coordinate.
As shown in Figure 16, combining GPS with moving map display and bearing information will allow accurate position information to be calculated. The vehicle moves from point 1 to point 5 and as it moves, the bearing to the transmitter will change. The previous known position will be stored in the MTIS and the line of intersection to the next bearing calculation will indicate the approximate position of the target.
Additionally, if the five points in Figure 16 represented separate vehicles in a convoy, the target location will be determined as each MTIS comes to bear on the transmitter. The intersection of the five lasers will indicate the vicinity of the target. Accordingly, it will be understood that use of the MTIS of the present invention for locating an immediate threat does not depend on communication from vehicle to vehicle.
Output Devices Liquid Crystal Display (LCD) A Liquid Crystal Display (LCD) is provided, and illustrated in exemplary form only in Figure 17, to interpret the direction and strength data received in Agrello DF
format and translates this data into textual messages for display. The display will typically show bearing, signal strength, type of signal, frequency, elevation and the range to the signal or target. If a GPS is used, the geographic coordinates will also be shown. If desired, the display may also be transmitted to a driver or gunner as a visor borne heads up desplay.
Light Emitting Diode (LED) Directional and Bearing Display The LED directional and bearing display (see Figure 18) device gives a visual indication of the direction a signal is coming from. It used 36 LEDs positioned in a circular fashion for a 10 degree resolution. Different colour LEDs are installed for the cardinal points for orientation purposes. A three digit numeric display consisting of three, seven segment LED modules is positioned within the LED circle to provide bearing information in the form of numbers from 0 - 359 degrees.
Audio Warning The audio warning will give an indication as to the type of signal being received by the MTIS unit. The warning tone is pre-programmed depending upon the type of threat encountered. The threats are determined by frequency, content and duration of signal.
For example a frequency is intercepted at 450 Mhz and consists of DTMF tones.
The corresponding threat is possibly a wireless teiephone triggering device. A
distinctive audio warning for an IED threat is heard on the speaker. A toggle switch can be employed to switch from Audio Warning to Receive mode whereby the original broadcast signal is heard such as voice, or data.
Personal Digital Assistant (PDA) A PDA can be connected to the main board to provide a graphical user interface and storage to display bearing, elevation, threat indication, GPS position data and other data available from the Doppler Main Board. An infra-red or other wireless interface can be employed to use the PDA remotely from the MTIS terminal, or as a secondary display system for additional operators.
Computer A computer can be connected to the MTIS terminal to provide a more sophisticated user interface, provide software updates to the on-board processors and for record and playback. The software updates can be firmware updates as well as threat profile updates.
Examples Three examples of how the system works are listed below:
a. Attempt to initiate an improvised explosive device (IED) - as a friendly convoy is moving, its MTIS system detects that someone is transmitting dual-tone multi-frequency signals from a nearby Motorola-type radio (DTMF signals are produced by pressing on the number keys). As this is a known method for initiating an IED, the system lets out an audio warning and uses its radio direction finding equipment to establish the x-, y-, and z-axes to the Motorola radio. Using that information, the system points a high-power stabilised laser pointer at the source of the transmission, and uses the laser range finder to determine the exact range. It also displays information on the type of transmission detected and the range on a screen. The forces using the MTIS system can now see the exact location and range to the person attempting to target them with an IED, and can take appropriate defensive measures.
b. Locating small arms fire - a friendly vehicle patrol comes under small arms fire in an urban setting in which there are many multiple-story buildings. They are able to determine the approximate direction from which the fire is coming, but cannot pick out exactly which apartments contain the gunmen. Returning fire under these conditions threatens to cause civilian casualties. Using the MTIS system's acoustic direction finder and laser pointers, however, friendly forces will rapidly be able to determine the exact point from which the fire is coming, allowing for much safer reaction.
c. Locating hostile forces - a group of hostile forces are preparing to attack a remote forward operating base (FOB) at night. They are communicating using hand-held radios.
The FOB has an MTIS system which detects these transmissions, gives warning that radios are active in the area, and indicates where they are by using the laser pointer.
Each antenna element is a'/4 wave whip antenna. They are typically mounted between .22 and .25 wavelength apart in a square pattern, on a ground plane.
Laser Range Finder The laser range finder part of the laser sub-assembly (see Figure 10) is a device which uses a laser beam in order to determine the distance to a reflective object.
It measures the distance to an object by measuring the time it takes for the laser pulse to be returned to the laser range finding equipment. The laser range finder in the MTIS mast is activated once a signal is detected. The MTIS stepper motor assembly will rotate the laser range finder to the correct bearing and the secondary motor in the laser assembly will raise or lower the lasers if the horizontally polarized antenna array is able to determine the relative elevation of the target. If the circumstances permit, a distance to the target will be determined and the information processed to the output devices attached to the MTIS
mast. If an elevation cannot be determined, the laser will remain horizontal.
Laser Designator The laser designator is a device which uses a laser beam in order to give a visual indication of the threat direction. The MTIS stepper motor assembly (see Figure 11) will rotate the laser to the correct bearing and the secondary motor in the laser assembly will raise or lower the laser if the horizontally polarized antenna array is able to determine the relative elevation of the target. The target area will then be indicated by the visual laser end point for engagement. If an elevation cannot be determined, the laser will remain horizontal.
Stepper Motor Assembly There are two parts to the Stepper Motor Assembly. The first is a stepper motor shown in Figure 12, that rotates the laser sub-assembly 360 degrees on the horizontal plane to the bearing detected by the (Vertical) Doppler antenna array and associated electronics. The second part shown in Figure 13 is a stepper motor that raises or lowers the laser sub-assembly on the vertical access to indicate relative elevation of the target.
A
microcontroller is used to translate the Agrello format bearing messages to the correct motor step to point to the lasers to the appropriate bearing. The Vertical Stepper Motor driver will receive Agrello format messages, however they are limited to 0-180 degrees (vertical).
Mast Sub-system Electronics Module This module (Figure 14) contains the Stepper motor microcontrollers, and delivers the required power to the mast systems, including the Stepper Motor Assembly and Laser Sub-assembly.
This module contains the batteries required to drive the Stepper Motors, Lasers and the Mast Sub-system Electronics Modules.
Input Devices Radio Receivers The FM radio receivers are used to determine the operating frequency for the direction finding unit. They are connected to the Antenna Arrays for horizontal and vertical polarization. The receiver speaker output is connected to the main board audio input.
The Doppler modulation results in an audio tone that is detected and. fed to the speaker of the MTIS display unit.
The radio receivers are typically set to scan the appropriate frequency spectrum and pause on that frequency if a signal is intercepted. Resumption of the scan can be manual or automatic.
GPS
The GPS input is optional, however the GPS data can be combined with the DF
Agrello format messages for plotting onto a map display. For example:
If the user of the MTIS is moving, the GPS and Doppler data can be combined to give a more accurate fix on the transmitted signal with one MTIS. As lines of intersection are made, the most likely position will be processed in real-time and the stepper motor will adjust the laser sub-assembly to the new coordinate.
As shown in Figure 16, combining GPS with moving map display and bearing information will allow accurate position information to be calculated. The vehicle moves from point 1 to point 5 and as it moves, the bearing to the transmitter will change. The previous known position will be stored in the MTIS and the line of intersection to the next bearing calculation will indicate the approximate position of the target.
Additionally, if the five points in Figure 16 represented separate vehicles in a convoy, the target location will be determined as each MTIS comes to bear on the transmitter. The intersection of the five lasers will indicate the vicinity of the target. Accordingly, it will be understood that use of the MTIS of the present invention for locating an immediate threat does not depend on communication from vehicle to vehicle.
Output Devices Liquid Crystal Display (LCD) A Liquid Crystal Display (LCD) is provided, and illustrated in exemplary form only in Figure 17, to interpret the direction and strength data received in Agrello DF
format and translates this data into textual messages for display. The display will typically show bearing, signal strength, type of signal, frequency, elevation and the range to the signal or target. If a GPS is used, the geographic coordinates will also be shown. If desired, the display may also be transmitted to a driver or gunner as a visor borne heads up desplay.
Light Emitting Diode (LED) Directional and Bearing Display The LED directional and bearing display (see Figure 18) device gives a visual indication of the direction a signal is coming from. It used 36 LEDs positioned in a circular fashion for a 10 degree resolution. Different colour LEDs are installed for the cardinal points for orientation purposes. A three digit numeric display consisting of three, seven segment LED modules is positioned within the LED circle to provide bearing information in the form of numbers from 0 - 359 degrees.
Audio Warning The audio warning will give an indication as to the type of signal being received by the MTIS unit. The warning tone is pre-programmed depending upon the type of threat encountered. The threats are determined by frequency, content and duration of signal.
For example a frequency is intercepted at 450 Mhz and consists of DTMF tones.
The corresponding threat is possibly a wireless teiephone triggering device. A
distinctive audio warning for an IED threat is heard on the speaker. A toggle switch can be employed to switch from Audio Warning to Receive mode whereby the original broadcast signal is heard such as voice, or data.
Personal Digital Assistant (PDA) A PDA can be connected to the main board to provide a graphical user interface and storage to display bearing, elevation, threat indication, GPS position data and other data available from the Doppler Main Board. An infra-red or other wireless interface can be employed to use the PDA remotely from the MTIS terminal, or as a secondary display system for additional operators.
Computer A computer can be connected to the MTIS terminal to provide a more sophisticated user interface, provide software updates to the on-board processors and for record and playback. The software updates can be firmware updates as well as threat profile updates.
Examples Three examples of how the system works are listed below:
a. Attempt to initiate an improvised explosive device (IED) - as a friendly convoy is moving, its MTIS system detects that someone is transmitting dual-tone multi-frequency signals from a nearby Motorola-type radio (DTMF signals are produced by pressing on the number keys). As this is a known method for initiating an IED, the system lets out an audio warning and uses its radio direction finding equipment to establish the x-, y-, and z-axes to the Motorola radio. Using that information, the system points a high-power stabilised laser pointer at the source of the transmission, and uses the laser range finder to determine the exact range. It also displays information on the type of transmission detected and the range on a screen. The forces using the MTIS system can now see the exact location and range to the person attempting to target them with an IED, and can take appropriate defensive measures.
b. Locating small arms fire - a friendly vehicle patrol comes under small arms fire in an urban setting in which there are many multiple-story buildings. They are able to determine the approximate direction from which the fire is coming, but cannot pick out exactly which apartments contain the gunmen. Returning fire under these conditions threatens to cause civilian casualties. Using the MTIS system's acoustic direction finder and laser pointers, however, friendly forces will rapidly be able to determine the exact point from which the fire is coming, allowing for much safer reaction.
c. Locating hostile forces - a group of hostile forces are preparing to attack a remote forward operating base (FOB) at night. They are communicating using hand-held radios.
The FOB has an MTIS system which detects these transmissions, gives warning that radios are active in the area, and indicates where they are by using the laser pointer.
Claims
1. A device for locating the source of an electromagnetic radiation (emr) transmission including:
a) a direction finding antenna for detecting said emr transmission and establishing, as an output signal, the direction in at least the horizontal x-y, plane, from which said transmission emanates;
b) a radio signal receiver for receiving said emr transmissions and establishing, as an output signal, the nature of said transmission;
c) a controller for receiving the output signals from said direction finding antenna and radio signal receiver, establishing the threat level of said emr transmission, and outputting:
i) a signal to a user discernable output device, to indicate the nature and threat level of the emr transmission; and ii) a signal to a 360° positionable laser pointer to provide a visible line pointing in the direction of the emr transmission.
a) a direction finding antenna for detecting said emr transmission and establishing, as an output signal, the direction in at least the horizontal x-y, plane, from which said transmission emanates;
b) a radio signal receiver for receiving said emr transmissions and establishing, as an output signal, the nature of said transmission;
c) a controller for receiving the output signals from said direction finding antenna and radio signal receiver, establishing the threat level of said emr transmission, and outputting:
i) a signal to a user discernable output device, to indicate the nature and threat level of the emr transmission; and ii) a signal to a 360° positionable laser pointer to provide a visible line pointing in the direction of the emr transmission.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2576754 CA2576754A1 (en) | 2007-02-02 | 2007-02-02 | Method and apparatus for detecting and indicating battlefield threats |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2576754 CA2576754A1 (en) | 2007-02-02 | 2007-02-02 | Method and apparatus for detecting and indicating battlefield threats |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2576754A1 true CA2576754A1 (en) | 2008-08-02 |
Family
ID=39671542
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2576754 Abandoned CA2576754A1 (en) | 2007-02-02 | 2007-02-02 | Method and apparatus for detecting and indicating battlefield threats |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2576754A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018144714A1 (en) * | 2017-02-06 | 2018-08-09 | Bae Systems Information And Electronic Systems Integration Inc. | Mono-bit multi-signals radar warning receiver |
| CN109616779A (en) * | 2018-11-21 | 2019-04-12 | 天津七六四通信导航技术有限公司 | A kind of Doppler high-frequency type antenna system |
-
2007
- 2007-02-02 CA CA 2576754 patent/CA2576754A1/en not_active Abandoned
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2018144714A1 (en) * | 2017-02-06 | 2018-08-09 | Bae Systems Information And Electronic Systems Integration Inc. | Mono-bit multi-signals radar warning receiver |
| US10371795B2 (en) | 2017-02-06 | 2019-08-06 | Bae Systems Information And Electronic Systems Integration Inc. | Mono-bit multi-signals radar warning receiver |
| CN109616779A (en) * | 2018-11-21 | 2019-04-12 | 天津七六四通信导航技术有限公司 | A kind of Doppler high-frequency type antenna system |
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