Acoustic systems for determining the shot
Rheinmetall has developed the AkSL detector, which is currently being offered as part of the Gladius retrofit kit.
The best situational awareness has become paramount for a soldier on the front line, whether he is on foot or in a vehicle. Thus, acoustic sensors that can tell the soldier where the enemy is firing from, have become commonplace on the battlefield. The capabilities of the systems wearable by the soldier are inevitably limited by their size, although new technologies come to the rescue in this area, while the speakers created for the machines became the “ears” of the machines themselves. Protection of military bases is another important area of application of acoustic systems for determining shot.
With the 2008, the Swats (Shoulder-Worn Acoustic Targeting System - shoulder-mounted acoustic targeting system) from QinetiQ North America is the most common situational awareness system of American soldiers deployed in the lower echelons. In total, almost 17000 systems were sold to the US Army, where they are known as the Individual Gunshot Detector. The system is also used by the US Marine Corps. The system is based on the 300-gram shoulder sensor unit, which incorporates microphones, a GPS receiver, a gyroscope, a magnetic compass and accelerometers. Having an accuracy in azimuth of ± 7,5 ° and in range 10% (the maximum stated range of 400 meters in open areas), this device turned out to be very reliable: the warranty return from military units is less than 1%. Swats provides the soldier not only the relative position of the source of the shot, but also records the coordinates in the system not only to update this relative position when moving the soldier, but also to distribute them among other fighters of the squad. Information is available through the hearing aid or display weighing 110 grams.
Available also for NATO countries through the NSPA program, the Swats system is in service with France, Australia and an unnamed Asian country, and was recently commissioned by a Middle Eastern country. Active trading is conducted in Europe and the Middle East. QinetiQ NA constantly updates the system by programmatically adding new languages and features; New algorithms are used to increase the detection range, and more efficient use of components has now increased battery life by about 14 hours. However, QinetiQ is already working on a completely new system that is waterproof, has a larger screen resolution with a simplified menu structure, a new, lighter, smaller sensor with data processing speeds greater than 50 times and 100 times more memory, which allows for more complex algorithms.
Information from QinetiQ Swats can be transmitted to a soldier, either through an audible signal or visually to the helmet.
Database protection is becoming one of the main tasks of shot detection systems; mounted on a tripod device Ears from QuinetiQ based in Afghanistan (above). Situation awareness of the crew is significantly increased when detectors such as Ears-VMS are installed on the machine (below)
QinetiQ has developed Ears FSS (Fixed Site System - Stationary Object System), which is beginning to attract interest as a defense system for military bases, as well as an Ears VMS (Vehicle Mounted System) system, which some customers have already requested. (photo above). However, the company is simultaneously developing a new system for a vehicle with increased angular and distance accuracy, which also provides an 3D image of the scene, which allows it to be used as an aiming device for remotely controlled combat modules. Currently, both systems have a readiness level of TRL 6-7 (system development stage), but even in 2012, they were shown to the American army. QinetiQ has not announced a release date for any of its new systems.
Boomerang
Another major player in this area is Raytheon BBN, which has sold more Boomerang 10000 systems to different countries (most of them deployed in combat areas). No significant reports have been made since the last review, but in the meantime, Raytheon BBN developed the Boomerang Warrior-XP system (here “P” means “Perimeter”) to protect bivouacs and camps. The device weighs less than 6 kg, it is much lighter and smaller than the original Boomerang system, and consists of a sensor and a power / network unit that allows you to connect multiple sensors to the Boomerang situational awareness system and thus cover 360 ° (although the Warrior XP can work and as a separate device). The system operates on a hardened laptop under Windows 7 OS and provides localization of the arrow in azimuth, range and elevation along with the 10-bit grid; the data is automatically combined for a more accurate solution, which is displayed on an intuitive screen in the form of a map. The system also shows a bullet detection zone, that is, a potentially dangerous sector. Enemy arrow data may be stored for reconnaissance purposes or for later viewing. According to BBN, the Warrior XP system detects over 90% of all shots. The characteristics of this system are: the determination of the flying bullet from 1 to 25 meters, the frequency of false alarms less than 1% and the response time 1,5 seconds, power is provided through the Ethernet channel, the operating time is unlimited.
Components of the Haltheon BBN Experimental System - sensors and display unit (sensors are simply mounted on the body of the helicopter)
The company is also developing a system that previously had the designation Haltt (Helicopter Alert and Threat Termination - Acoustic, a warning and threat identification for the helicopter - acoustic), but now known as Boomerang Air. It uses modified software to filter out the own noise and vibration of the aircraft. Its sensors are integrated with the helicopter body and thus the system is not easily identifiable. The number of sensors is limited to the type of helicopter and the size, although the company refuses to announce any additional details.
PDCue
Another vehicle system, AAI Textron's PDCue (short for Projectile Detection and Cueing - shot detection and signaling), is based on four sensors mounted at the corners of the roof, which provides full coverage on 360 °. Separation of sensors provides high accuracy in azimuth and elevation, the error for both angles is about ± 1 °, the error in range is less than 25%, but decreases at distances above 350 meters (the maximum distance is 1,2 km). The PDCue is installed on the M1151 Humvee armored and integrated with the Crows II combat module for the purpose of conducting rapid assessments. The company did not provide any additional comments on the latest developments, as it currently participates in several “sensitive” applications.
AAI Textron has developed a PDCue integrated with the Crows II combat module, which is installed on the M1151 Humvee of the American Army
The ancestor of detecting the sound of a shot - the company 01dBMetravib - recently developed a rifle system, weighing less than 400 grams. Below in the photo you can clearly see how the LEDs of the system help the arrow to direct weapon on the source of the shot
Video presentation systems from the company Acoem-Metravib
Pillar
In the middle of 2012, Acoem-Metravib added a new product to its line of acoustic sensors. The Pearl device (Personal Equipment Add-on for Reactive Localization — an addition to personal equipment for reactive localization) has already been demonstrated at the prototype stage. It is intended to provide a single fighter with an inexpensive system for detecting and locating a shot, mounted on the Picatini guide of machine guns, assault and sniper rifles. The system is a single-unit device that includes a miniature acoustic matrix of sensing elements with built-in electronics, an integrated processor unit with a gyrometer, and a human-machine interface showing the direction of the shot in azimuth and elevation by means of green and red LEDs to the soldier. When a soldier moves away from his initial position, the Pearl system allows continuous tracking of the target until the operator reboots the system. Three buttons allow you to switch the system: "on / off", "day / night" and "next shot / reset". The weight of the Pearl device is 400 grams, it detects supersonic ammunition caliber 5,45 - 20 mm.
According to Metravib, the probability of detecting a shot is more than 95%, localization errors in azimuth and elevation angle ± 10 ° and in range ± 20%, reaction time less than one second. When operating on two standard batteries (AA 1,5 B), low power consumption (less than 2 W) of the device guarantees a working time over 12 hours. The RS232 or RS485 ports are intended for exporting indications of potential targets to an electronic sight, which allows the soldier to maintain his aiming position. The company has actually integrated its product with the Sagem Sword TI. It is planned to further integrate the device with target localization systems (for example, Sagem Sophie) to equip sniper scouts, as well as with low-cost remote-controlled weapons. Metravib is ready to configure its system for installation on helmets, shoulders or backpacks, or, for example, as a separate wrist display, and has already shown the Pearl system integrated with the helmet display. The first order for 20 Pearl devices already in production was received from Brunei, and further bulk orders were expected in the fall of 2013. Since the use of Pearl can lead to a change of doctrine, Metravib has developed a Blue Pearl version, featuring special software for use with single ammunition during combat training.
Of course, Metravib still offers its Pilarw system for vehicles and stationary objects. Compared to the original Pilar system deployed in Sarajevo in 1995, the current system is able to accurately identify in real time the source of fire not only of small arms, but also RPGs, mortars and anti-tank missiles. The newest option for Pilarw Vehicle vehicles has a reaction time of less than two seconds and ensures accuracy in azimuth ± 2 ° in the parking lot and ± 5 ° in motion. Accuracy in elevation is ± 5 °, while accuracy with active shelling in range ranges from 10 to 20%.
The Pilarw system also detects the caliber and gives an audible warning. Since this system is designed for vehicles, it can provide the coordinates of the fire source when connected to an inertial and / or GPS navigation system. Obviously, it can be integrated with remotely controlled weapons, adding the possibility of automatic targeting and hitting targets using external target designation commands. Two modes are available: urban (for active shelling only) and rural for all types of shots. The vehicle option has a weight of 2 kg, for work it expands and becomes a height of no more than 50, see Calculation Interface Module installed on the machine weighs 3,6 kg. The most recent successful order for Pilarw systems came from the French army on the VAB machine modernization program, which received the designation TOP. In France, the system received the designation Slate (Système de Localization Acoustique de Tireur Embusqué - the acoustic localization system of the shooter in ambush), it was integrated with the Kongsberg Protector M151 ACS for automatic re-deployment to the target. Since February, 2012 has been supplied to 80 of such kits.
For its part, the Pilarw Area system is the newest option, which allows you to connect up to 20 antennas to one electronic unit, and thus covers the area of 1x1 km, while having increased accuracy. The system was sold to Italy and Germany, and is currently deployed in Afghanistan. Numerous demonstrations of the Pilarw Helicopter were held, orders are expected for it, especially from South America. A set of two antennas can be mounted on light helicopters, and a set of four antennas on heavy ones. Depending on the noise generated by the helicopter, depending on its size and flight speed, the system can provide a rough indication of the source of fire, in front, behind, left, right, or a more accurate indication, yielding "circular localization", range and caliber. Metravib does not rule out further development of the system, for example, in network systems for vehicles, but is looking for a major integrator to complete the project.
The Pilar 4 Microphone Kit is designed to protect vehicles and infrastructure
Avisa Company
Using the experience gained in the automotive industry, the Dutch company Microflown Avisa has developed innovative acoustic vector sensors AVS (Acoustic Vector Sensor) to detect and localize shots of small arms, artillery fire, aircraft and vehicles. AVS can not only measure sound pressure (a typical measurement made by microphones), but also gives the acoustic velocity of the particles. The single sensor is based on Mems technology (microelectromechanical systems) and measures the air velocity through two tiny, resistive platinum strips heating to 200 ° C. With the passage of air flow through the plates, the first wire is slightly cooled and due to the heat transfer the air receives a certain part of the heat. Consequently, the second wire is cooled by the already heated air and, thus, it is cooled less compared to the first wire. The temperature difference in the wires changes their electrical resistance. There is a voltage difference proportional to the acoustic velocity, and the effect is directional: when turning the air flow, the area of the temperature difference also rotates. In the case of a sound wave, the air flow through the plates changes in accordance with the waveform and this leads to a corresponding change in voltage. Thus, a very compact (5x5x5 mm) AVS sensor weighing several grams can be manufactured: the sound pressure sensor itself and three orthogonal Microflown sensors at one point.
The company Microflown Avisa emphasizes that its technology provides better accuracy compared to microphone systems in azimuth and range, although it does not provide elevation angles (see the table). Tests conducted in the Netherlands and Germany showed that the AVS-based system can identify the location of the mortar round with an accuracy of 2% in range and less than 0,5 ° in azimuth. After intensive development, Microflown Avisa received the first contract for practical target designation and enemy fire detection, followed by a second mobile system contract and similar tasks, and the third included the delivery of an enemy fire localization system to protect the Netherlands Embassy in Kabul.
Video of the shot detection system from MICROFLOWN AVISA
Avisa has developed miniature sensors that not only measure sound pressure, but also the vector acoustic velocity of the particles. Avisa is working on integrating its sensors into microdrones based on their small size and weight.
Avisa used its technology to develop a system that allows you to accurately determine the coordinates of the leading machine gun or cannon. This system was installed at the Dutch Embassy in Kabul
Another contract provides for the development of an AVS solution for installation on vehicles. A research and development contract worth one million euros was signed at the beginning of 2013 for a period of two years. This solution, designated Whelac (wheeled acoustics - wheeled acoustics), will provide the vehicles with an all-acoustic 3D acoustic situational awareness system. AVS is able to locate and classify small arms, missiles, artillery, mortars and RPGs, as well as helicopters and ground vehicles. The system should, in spite of the engine noise, provide full target detection capabilities in a car moving at speeds up to 80 km / h. Since acoustic awareness inside armored vehicles is severely impaired, a Whelac solution could increase crew safety by issuing warnings about attacking threats. Among other things, the use of the network option is also considered. The reduced size, weight and power consumption of shot detection systems based on AVS technology makes them an excellent solution for other systems, such as light UAVs. An application known as Walking Ears (walking ears) is being developed. The company thrives, 40 employees work in Microflown on several innovative programs. India is the first potential buyer of the company's products for its UAVs.
Sniper Egg (Sniper Egg)
In response to the British Defense Ministry’s “Contest of Ideas” initiative and the urgent operational requirements, Ultra Electronics has used all its rich acoustics experience when developing a rifle shot locator. The Sniper Egg device (originally designated RMGL) is a monoblock system capable of identifying and localizing the source of high-speed 5,56-12,7 mm bullets. A 450 system weighing grams can be mounted on a Picatini guide on the right side of the rifle. It is characterized by a characteristic block of microphones in the form of "eggs" and a display of 160x128 pixels serving as a human-machine interface.
Ultra Electronics' Sniper Egg device can detect a bullet at a distance of 1200 meters
When fired, the Sniper Egg shows the soldier the direction on the dial gauge and while the soldier turns in the direction of the threat, the miniature, triaxial, inertial tracking system provides constant motion compensation and the needle moves in the direction of the 12 clock. To fine-tune the azimuth and elevation, the hour hand on the screen changes to the reticle when the angle between the rifle and the target becomes smaller than 30 ° when turning to the side of the shot. The nominal azimuth and elevation accuracy is ± 5 ° and 15% range (the distance is shown in the lower right corner of the screen, and the number of detected events can be seen in the lower left corner of the screen). A beep is available. The detection range is from 30 to 1200 meters. The Ultra company declares the probability of correct detection and localization over 90% at a low frequency of spurious signals. For smooth movement of graphic elements on the display, its update rate is 10 Hz.
The Sniper Egg is waterproof and is powered by two AA batteries, providing up to seven hours of battery life (the battery charge is shown in the upper right corner of the screen). A simple menu allows you to set system parameters, such as display brightness (the display is compatible with night-vision goggles), maximum and minimum ranges.
The company Ultra Electronics, based on the available technologies, is currently working on an enemy fire indication system for helicopters, however, no information on the status of this program has been provided. The company also received funding for research in the field of acoustic detection of low-speed ammunition, such as RPGs.
Pinpoint
The American company Cobham, in collaboration with BioMimetic Systems (BMS), has developed a new family of acoustic detection systems for shots, designated PinPoint. Two options were made, one for dismounted infantry and one for vehicles or stationary objects. The first is in the form of a shoulder block of sensors, which provides the range, direction and vertical angle. The data is presented in the form of an audible message or displayed on the display in the form of a wristwatch of size 45x51 mm. This can be either the range, direction and elevation angle, or the coordinate grid. Two AA batteries for a system with a power consumption of 1 Watts allow you to work from 10 to 12 hours. The dimensions of the shoulder sensor are 89xXNNUMXx89 mm, and the total mass is less than 26 grams.
Acoustics Specialist, BMS has developed applications that combine analog and digital hardware with an asynchronous signaling method, known as event handling, that works on the neurological function. This allows the sensors to provide a wide dynamic range, stable performance and high adaptability to external conditions. According to Cobham and BMS, the system exhibits high performance in a noisy and echoing urban space. One hundred milliseconds after detection, information about the source of the shot is displayed; thanks to the built-in sensors, when moving a soldier, relative position data is updated. Figures for accuracy by Cobham are not presented.
The display in the form of a Cobham PinPoint wristwatch shows the direction and distance to the source of the shot.
The PinPoint Dismount soldier option can detect and show a shot every 30 milliseconds thanks to fast signal processing algorithms in the time domain; the system can store in memory up to 1000 shots. However, for practicality, the infantry system allows you to call the latest 15 shots. The PinPoint Vehicle system has similar characteristics regarding reaction time, but the accuracy is higher due to the larger sensors. The system is a low-profile pyramid that has four microphones (one at each vertex). The common sensor has dimensions 337x356x108 mm and weight 2,27 kg. The 3 W system is powered from the on-board network, the allowable voltage is from 8 to 28 B. Like the Dismount option, the system has several connectors: serial port, audio, GPS, USB and power. To display information on the localization of the shooter, a standard hardened tablet with Windows OS is used, and the system can be connected to a common network via Ethernet or a radio station. It can also store 1000 shots, although you can trigger the latest 250 shots directly in the car. Both systems are currently available, and Cobham has already received orders from military customers and paramilitary organizations.
ASLS
Rheinmetall Defense Electronics has developed the Acoustic Shooter Locating System (ASLS) acoustic localization system in order to increase the level of vehicle crew protection. It consists of a circular base housing an energy efficient signal processing system and a battery, and an “antenna” consisting of eight special microphones designed for high sound pressure levels and providing circular coverage. Initially, each microphone was mounted on a vertical axis, but a new circuit was presented at the Idex 2013 exhibition. Eight horizontal rods with microphones depart from the same vertical carrier axis, while their relative position in space remains the same. This decision was made to simplify and reduce the cost of production, and for greater reliability, microphones now protect the framework from steel pipes. The detection range on 20% is greater than the detection range of the weapon itself, while the angular accuracy during stop and in motion is respectively less than 2 ° and 5 °. The refresh rate is less than 1,5 seconds, and range accuracy is typically ± 10%. According to Rheinmetall, the frequency of false positives is lower, even when the system is operating in an urban environment and a cramped space. The antenna consumes less than 15 W, the voltage is 10 - 3 V, and the battery at the base allows you to work independently of the network of the machine, but you also naturally need a remote display.
One of the intermediate versions of the ASLS shot detection system from Rheinmetall (above) at IDEX 2013. The final version is placed in a corpus similar to the corpus of the SAS situational awareness system; thus, two systems can be installed in a single package (below)
The base of the ASLS system also contains position sensors in space and a GPS receiver to compensate for the movement of the machine. Signals received from ASLS are fed to a special display, to the battle management system, as well as to the combat module for automatic transfer to the source of the threat, while the crew also receives an audible warning. During tests in the German army, the system confirmed its characteristics, but its height dimensions create the problem of diversity with the combat module when installed on light vehicles.
The ASLS system is almost completely refined, and when the first customer appeared, its production could begin quickly. However, Rheinmetall, based on its rich experience, is currently offering a new system. Eight microphones are installed in a container that has the same shape as the container of the Situational Awareness System (SAS) situational awareness system - an optoelectronic system for armored vehicles that provides close observation. An acoustic sensor can thus be installed on top of an optoelectronic station. However, the speaker system guarantees a circular 360 ° coverage and is usually installed in front of the machine, while the opto-electronic station provides 180 ° coverage, thus two such modules are needed. According to experts from Rheinmetall, the new sensor retained the same azimuth accuracy as that of the ASLS, although the reduced height reduced its accuracy in elevation. The new antenna weighs 4 kg, its width is 280 mm, depth 260 mm and height 180 mm.
A miniature version of AkSL (Akustusches Schützen-Lokalisationssystem) is also developed by Rheinmetall. This company submitted its application to the Bundeswehr at the end of April 2013, in response to a request for proposals, to which several competing companies responded. AkSL was conceived as a separate module, but it is easily integrated into computer systems. It is an acoustic sensor unit worn on the shoulder, in which position and orientation sensors are placed, which allow the location of the threat to be maintained even when a soldier moves. Data of azimuth, vertical angle and range are displayed on the display in the form of a wrist watch (a cable is connected to it based on German requirements). The display also shows the localization scheme and its orientation, event time and battery charge. The audio message — a reference to the direction of the target and the distance — is also sent to the headset under an hearing protector or directly to an active hearing protection system, such as Peltors; these requirements were developed in conjunction with the German special forces. The laboratory has already tested the wireless connection to the wrist display via the standard ZigBee channel. On the back of the sensor has two buttons: the right button "on" and "off" also controls the state of the system, and the left controls the volume and magnetic calibration. The third button on the front of the sensor allows you to repeat already recorded events and select external conditions, or rather a quiet scenario or urban scenario. In this case, algorithms are chosen that represent a compromise between the false response / detection ratio and the range.
As a rule, the AkSL system provides azimuth accuracy of ± 5 °, in range ± 10%, and has a maximum range of 20% higher than the range of the weapon that was fired. According to Rheinmetall, the accuracy of this system is less than the accuracy of a larger system, but fully meets the needs of the infantryman. In its current configuration (sensor, display and cable), the AkSL system weighs less than 500 grams and is powered by two CR123 batteries. At the end of the 2012 of the year, the AkSL was also successfully tested on helicopters (two sensors on each side) at different flight conditions, starting from a hang and ending with the speed of 200 km / h. Helicopters flew over training zones, from which fire was fired in special modes.
ShotPoint is a network system developed by Software Integrated Systems (Isis) Vanderbilt in collaboration with Databuoy LLC
Databuoy company
In the United States, the Vanderbilt Institute of Integrated Software Systems (Institute for Software Integrated Systems - Isis Vanderbilt) has been working on anti-sniper systems for several years. His latest developments are aimed at creating network sensors. He recently teamed up with Databuoy LLC to produce and sell ShotPoint. It consists of several nodes, each of which has four sensitive microphones, a GPS and an inertial system, an electronic panel with embedded software, a radio transmitter, and a corresponding battery pack.
Based on its position relative to the shooter, the node can receive a muzzle flash and a shock wave, or only a shock wave. The nodes form a special network and transmit information about the discovery over the network to the control unit, which combines all incoming data into a single optimal solution. The control unit then sends the data to the Internet site and they are displayed on the corresponding display. Detection event data from multiple nodes is combined for more accurate shooter localization, bullet trajectory calculation, and caliber estimation. According to Databuoy, the average error of the ShotPoint system is less than 1° or three meters in azimuth, and less than 7 meters in range when deploying nodes with a recommended distance of 50 to 150 meters between each. The detection probability exceeds 95%, and the response time is less than a second. Currently, each node is a cylindrical container with a diameter of 170 mm and a height of 120 mm, it contains a folding antenna and a radio station operating at a frequency of 2,4 GHz, as well as four 4D batteries. They weigh a third of the mass of the entire system 1,68 kg; thanks to low power consumption (0,5 W), each module can work autonomously for five days. However, to meet different customer requirements, Databuoy is ready to offer kits of different composition. ShotPoint nodes are easy to install, determine their own position and create their own network. The data fusion and control software is compatible with Android OS and can run on tablets. ISIS Vanderbilt and Databuoy began marketing the ShotPoint system in early 2013 and have participated in several applications. Shotpoint can also be used to protect troops in outposts and small temporary infrastructure. A potential customer is considering this system for ground robots, which can follow the leader.
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