Denying Access
Written by Peter Buxbaum
SOTECH 2010 Volume: 8 Issue: 5 (July)
THE UNATTENDED GROUND SENSORS THAT SPECIAL
FORCES USE TO COLLECT INTELLIGENCE AND
TO AID IN SURVEILLANCE RANGE FROM SIMPLE
ALARM SYSTEMS TO SOPHISTICATED NETWORKS.
Remote, ground-based electronic sensors, used to collect intelligence on enemy movements and to aid in surveillance and reconnaissance, have been available to the United States military for decades. But sensor technology has progressed dramatically since the war in Vietnam, when acoustic and seismic sensors, which pick up sound and vibration respectively, were dropped in the vicinity of Viet Cong supply routes.
In earlier times, all of the processing, analysis, and interpretation of the sensors’ work was done on the back end, by highly trained personnel working with the technology of that day. Today’s unattended ground sensor systems come in a variety packages and flavors. Besides acoustic and seismic capabilities, sensors these days are also capable of electro-optical, infrared, and magnetic detection.
Today’s unattended ground sensor (UGS) systems vary from simpler intrusion detection systems which raise an alarm when a perimeter has been breached, to those which can identify and classify an approaching threat and transmit that information directly to decision makers. Still others are capable of activating cameras to provide users with imagery of potential targets while others are combined with munitions which can target those threats.
Qual-Tron Inc. manufactures a standard monitoring system known as the Mini Intrusion Detection System (MIDS) and two enhancements to MIDS known as MMIDS and EMIDS.
“They are all intrusion detection systems,” explained Dan Chambers, the company’s vice president for sales and marketing. “A range of different unattended ground sensors can be selected to work with the system which are compatible with all three systems.”
The Qual-Tron systems are not sensors themselves, but are monitors which can keep track of multiple compatible sensors and transmit information from those sensors to users. The MIDS system operates on a single frequency and can monitor 32 sensors, MMIDS is a single frequency system which can keep tabs on 999 sensors, while the highend EMIDS combines the MMIDS prowess with a multi-frequency capability.
MIDS simply transmits an intrusion alarm to operators while EMIDS is also capable of monitoring and transmitting information on the health of the sensors. “EMIDS can be programed to report in from every hour to 24 hours,” said Chambers. “That is an easy way to verify that all sensors are operational.” All of the systems are capable of working with a variety of sensors, including passive infrared, magnetic, and acoustic sensors. Infrared sensors detects changes in heat patters, magnetic sensors monitor changes in the magnetic field, while acoustic sensors monitor noise levels. The Qual-Tron system are also capable of working with infrared breakbeams, which activate an alarm when a pulse beam is broken by an intruder a well as break wire sensors, mechanical devices which activate when a physical wire is broken.
“The type of system to be used depends on the needs of the customer,” said Chambers.
The alarms can be sent to handheld receivers, perhaps in the hands of a mobile patrol, or to a fixed monitoring station. Although the system does not classify targets, Chambers contends that using the right combinations of sensors for a particular situation will allow users to develop situational awareness.
“We train people to use combinations of sensors,” he said. “Depending on which are activated you can determine what the target is.”
For example, a magnetic sensor will be activated only by a metallic object. Magnetic sensors might be placed directly at the side of a road and 10 meters off the road. A passing vehicle would likely trigger both sensors while a person walking by with a weapon would trigger only one of them.
“By using a combination of sensors you can figure out what is happening out there,” said Chambers.
The Qual-Tron systems can also be integrated with external camera monitoring systems. In that case, a sensor alarm would activate cameras in the area of intrusion so that operators can take a look at that specific location.
All branches of the U.S. armed services have purchased Qual-Tron products, according to Chambers, generally as part of larger packages through system integrators. They have been used for force protection, as well as to provide long-range surveillance of remote locations such as passes, roads, and border crossings.
Other sensor systems include robust software and computer processing capabilities on board that allow it, by looking for target characteristics, to define what it is hearing and feeling, whether it be a tank, a heavy wheeled vehicle, or an individual on foot. One example is the Battlefield Anti-intrusion Sensor (BAIS) produced by L-3 Communication Systems and fielded by the U.S. Army.
“BAIS is meant to serve small dismounted units with extremely lightweight and lowpower usage devices,” said Robert Lisowski, director of RF systems for L-3 Communication Systems – East. “The system is intended to support platoon level action and to provide data in real time to a platoon leader. It is also capable of pushing up information to higher levels primarily to support small units.”
The sensor, which is equipped with seismic, acoustic, and magnetic components, can classify personnel, wheeled and tracked vehicles, and helicopters, and is being enhanced to identify wheeled vehicles by weight. “The magnetic sensor detects metallic objects and vehicles,” said Lisowski, “and is also capable of reporting on the direction of travel. Through a software enhancement, we are also able to provide some estimation of the speed of the target.”
Recent software enhancements to the BAIS seismic acoustic sensor allows it to detect helicopter traffic. “This was expressed as a priority by our customer,” said Lisowski.
Platoon leaders receive sensor data on small handheld units. In another recent enhancement to the system, handheld device users can remotely program the sensors, to modify their parameters, or to turn them off to conserve battery power. “Once in place, users can decide to modify the sensitivity of the sensor to detect only personnel and not vehicles or vive versa,” said Lisowski.
The Army’s ill-fated Future Combat System produced unattended ground sensors that persist under the nomenclature of Brigade Combat Team Modernization (BCTM) UGS. Textron Defense Systems, the UGS prime contractor, is supplying two kinds of ground sensors to CTM.
The first is for urban operations, to help troops verify that areas under their control are still clear of enemy combatants. “Imagine that a solider goes into a building somewhere in theater and clears a particular room or hallway or building,” said Jay Johnson, the company’s senior director for ground systems. “He wants to make sure no one comes in behind him to reoccupy the area so he carries a sensor system which he puts up on his way out.”
This particular sensor combines a motion detector and a small camera with a night illuminator. Once the sensor detects motion, the electro-optical sensor comes into play to take a picture of the intruder.
The other Textron sensor detects vehicles. This tactical sensor can identify everything from tanks to pickup trucks to boats approaching a shoreline and helicopters hovering close to the ground. The tactical sensor combines acoustic, seismic and electro-optical capabilities.
“Once a threat is picked up the sensor starts sharing information with other like sensors in the field,” said Johnson. “They triangulate the sounds and vibrations to be able to track the threat vehicle. This is conveyed to a soldier operating laptop at a command and control station. The soldier can then activate the electro-optical sensor to take a picture of it.”
The camera can also be activated through an infrared sensor which acts as a tripwire should a suspect vehicle pass its way. The Textron sensors have been authorized to go into limited production for user tests. “The army will decide what to do with them after the user tests are completed,” said Johnson. One sensor system which integrates imagery comes from the Xetron unit of Northrop Grumman. Around 900 of the Scorpion UGSs have been delivered to the U.S. Central Command, primarily for use in Iraq an Afghanistan, according to Mike Coster, Xetron’s UGS business area manager.
“Scorpion involves sensors cueing other sensors,” he said. “Seismic, magnetic, and acoustic sensors are placed in remote areas of interest for months or years at a time. When a detection is made, the sensors send a wireless message to a gateway to wake up a camera that peers into the area and sends images over the network to anywhere in the world. The idea is to obtain actionable intelligence in the form of imagery so the user knows for sure what it is.”
Scorpion is now on its second iteration. Scorpion 2 provides the same performance as the earlier version, which has been around since 2006, but is smaller, lighter, and easier to conceal. Scorpion 2 is now in low rate initial production. The first prototypes were tested last year.
Scorpion is meant for higher level use than the Qual-Tron systems or BAIS. “The imagery is meant to get back to an analyst who can then link it up with larger common operating picture system,” said Coster. “Most of our customers believe imagery is critical. The activity can show up as an icon on a map and a human in the loop can determine what to do next.”
What happens next could be aiming a munition on the target identified through the use of the sensors. Textron is working on a weaponized anti-personnel sensor called Spider, produced as part of joint venture with ATK, and an anti-vehicular sensor called Scorpion (a different Scorpion).
“With this mix of sensors and munitions, the sensor sends a signal to solider on a laptop that a particular threat has been identified,” said Johnson, “and the controller would then decide whether the target is friend or foe and whether to engage.”
Spider can be deployed with the use of a tripwire if force protection capabilities are needed immediately. It can also be configured in a more sophisticated way so that a set of acoustic, seismic, and magnetic sensors can track a target and then advise an operator to make a decision about engagement.
“The decision may be to do nothing. The target may be a U.S. patrol coming back from a mission,” said Johnson. “The operator may also send the information to the command structure so that the rest of the command team has the information. Or, the operator may engage the target once it has been determined it is an enemy target that he is authorized to engage.”
With the Scorpion system, the operator may decide to arm the system and fire or he can authorize the system to engage when it best senses that the environment is correct. “Think of the Spider munition as a replacement for the older kinds of land mines,” said Johnson. “But it is clearly not a land mine. It is a compliant network munition.”
The Scorpion munition pitches a skeet 50 to 60 meters in the air, at which point it finds the target, locks on it, and fires a penetrator into the vehicle’s engine compartment. The Spider munition is in production and was recently placed in the hands of U.S. forces. Scorpion is still in research and development, with a milestone decision expected in around 18 months.
The networking of ground sensors is important for missions such as force protection, perimeter control, and intelligence, surveillance, and reconnaissance, according to Mike Casey, director of business development at Trident Systems Incorporated, a San Diego-based company. Trident manufacturers small, lightweight sensor nodes called the Sentry and the Recce, a heavier duty model. These nodes are essentially an integration platform for a variety of different sensors such as motion, magnetic, infrared, and electro-optical. The nodes communicate with each other over a 2.4 GHz ultra-wideband network.
Trident’s architecture differentiates between the sensor and the node in order to allow for custom designed sensor networks. “The node handles all of the functions that are common from mission to mission and which are necessary to get information from the sensor back to the operator,” said Casey. These include communications, performance and power management, and GPS geolocation.
“One mission may need a camera, another a seismometer, or it may need multiple sensors,” Casey explained. “In each the operator needs to be at some distance from the sensor field itself. Our approach provides a flexible toolkit to build a sensor network that is custom to the mission while still having common communications and operator displays from mission to mission.”
Trident has also configured its nodes so that “the network itself is a sensor,” said Casey. “If someone walks between two nodes and the signal is disrupted, that activity can trigger an alert for sensors such as the infrared or electro-optical to activate.” ♦