Networking System Spins Sensor Web

March 2002
By Maryann Lawlor
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Technique provides 64-fold increase in radar sensor utility.

The potential of network-centric operations is growing with the capability to link, interpret, process, manage and share data from multiple sensors in near real time and throughout a battlespace. This information could be delivered directly to a commander’s laptop computer to provide a clearer and more complete picture of detected threats.

Sensor technology is a key component of obtaining situational awareness in an area of operations. Currently, however, each sensor monitors distinct sections of the battlespace. By networking various types of sensors, processing the information they gather, then employing smart technology to sift through it, commanders could respond to activity in a named area of interest quicker and with more precision.

The LinkSensors sensor networking system is the brainchild of researchers at Lockheed Martin’s Naval Electronics & Surveillance Systems–Radar Systems in Syracuse, New York. At the core of the system is a real-time database management approach that is based on a technology currently used on U.S. Navy submarines. When an entire LinkSensors system is deployed, it would manage tactical- through strategic-level sensor information using the existing basic communications lines, and it would not require dedicated equipment other than a dedicated commercial laptop computer. The system communicates on available bandwidth and coordinates information from ground and air surveillance sensors as well as space-based assets.

Charles K. Pickar, program manager, sensor networking, Lockheed Martin, explains that part of the capability is a more sophisticated version of some basic technology that is available on the Internet today. The system enhances the conductivity between and among individual sensors and the commander, he offers. “LinkSensors preprocesses the data before it goes into the command and control [C2] node. It is not something that is going to interfere with the commander’s duties or take time away from commanding,” he adds.

LinkSensors automates sensor activities and obtains, integrates and produces quality data under dynamic conditions by managing and coordinating disparate sensors. To create the links, the sensor systems would be outfitted with an input/output device that would be tailored to the interface of the specific sensors. The device would be linked to the LinkSensors system either as a wired or wireless connection. Software would be installed on a dedicated commercial laptop computer.

LinkSensors consists of four basic components that constantly communicate with each other. The preprocessor module performs functions such as updating the sensors’ status, sensor control and data gathering. It contains the sensor-specific parameter database that interacts with a key piece of the system called the sensor manager. In addition, this module includes an element to request communication resources and a system that filters data as required.

The second and third components are the data fusion processor and the sensor manager, which contains inference agents, also known as smart or intelligent agents. These items interact with each other to pass along sensor information and continually monitor the sensor network for specified conditions. The intelligent agents determine the best sensor type to employ to acquire complete target or activity identification. They also determine the type of sensor data required to obtain comprehensive target identification or to assess the situation or threat.

The communications manager is the fourth and a critical component of the system, Pickar says. “Data is constantly being transferred on a communications network, and that becomes a problem when priority information must get through. Data moves on the communications lines like people traveling on a train. Important information gets put on the train and goes at the same speed, but critical information needs to get to the commander quicker.

“The communications manager helps solve this problem. The commander sets the criteria for information that must be received immediately. When those criteria are met, the communications manager directs unaffected sensors to stop so that the priority message can be sent through at once. This all happens in real time,” he relates.

During a mission, a commander would task the sensor networking system to gather the required information and then monitor the collection of that information in the named area of interest. For example, to protect troops a commander might deploy acoustic and seismic sensors to detect vehicles approaching the area. When the sensors receive data from sound or vibrations, the inference agents monitor the information as it is sent to the data fusion processor. If the data matches the commander’s criteria, the system automatically requests additional information from the sensors. When the sensors that originally detected the sound or vibrations cannot acquire further data, the inference agent will extend the request to other sensors such as radar or unmanned aerial vehicles in the named area of interest.

“As a result, C2 operators will also be able to extract sensor data from fusion nodes or send commands back to sensors. Sensors will talk with other sensors and update associated fusion nodes, which in turn can update C2 centers, warfighters and other command levels,” Pickar states.

The LinkSensors system is a sensor management tool and not a command and control node, he emphasizes. “Sensor networking focuses on the control side of command and control and not the command side. That’s an important distinction for us. The system provides the ability for the commander to control.

“We’re focusing on the control of those sensors to exploit the information from them and get more bang for the buck. Today, we are sensor rich, but we don’t have the ability to control those sensors,” he says. The LinkSensors system provides sensor control for five levels of the three-dimensional battlespace environment, including satellites, aircraft, unmanned aerial vehicles (UAVs), tactical UAVs and the tactical commander’s assets such as radar, he adds.

Fusion preprocessing of the data at the sensor level increases performance of the sensor network. In addition, because information can be passed from sensor to C2 node, from node to node and from sensor to sensor, if one segment is damaged or destroyed, the system can be reconfigured rapidly and continue to operate, he points out.

The system provides transparent interfaces between sensor levels. Because the focus is at the sensor level, multiple paths for transferring information are created. Along with addressing current military concerns about interoperability, it is designed with an open architecture so that it can be used in a range of equipment from legacy systems to new technologies, Pickar maintains.

Processing data at the sensor level helps address the military’s concern about bandwidth management, he indicates. “Performance of a sensor is very high, but it takes up a lot of your assets. LinkSensors processes the data at the sensor level so that the commander can still get the information over low bandwidth,” he explains.

In a high bandwidth environment, raw signal fusion provides an optimally processed signal and improves interference rejection. However, this requires a high bandwidth datalink, and fusing raw signals from diverse sensors presents difficulties. In a moderate bandwidth environment, signal processing produces a manageable processing load, offers increased sensor accuracy and provides increased threat and situational assessment performance. But semiprocessed data fusion can miss hard to detect signals. In addition, without a sensor manager, there is no compensation for single-sensor degradation. The LinkSensors sensor management technology recovers signals of interest and assists in compensating for a changing area of operations or mission even when only moderate bandwidth is available.

A key advantage of LinkSensors is its ability to operate in a low bandwidth environment, Pickar states. The sensor does sensor-specific calibration and clutter mapping, and all the processing is tailored to the individual sensor. Although only high-confidence information can be acquired, some low-confidence data can be recovered.

The system could be deployed at any level of command, Pickar maintains, because different echelons would require different types of information.

“We’re building on technologies we’ve had in the past. All the services have approached us to talk about this. In a missile defense environment, it has all kinds of applicability. If you’re looking at a bullet in the sky, it’s better to have as many sensors as possible. For the [U.S.] Marine Corps, it would give them the ability to, while at sea, tap into systems on the ground so they already have an idea of what they’re coming into when they land on the beach.

“When we’ve made presentations to military personnel, they say it looks like we’re trying to put ourselves out of business. But this is an improvement to sensors because you can get a whole lot more out of the sensors that you have,” Pickar remarks.

LinkSensors complements the military’s goals for future warfighting tactics, Pickar contends. “As we move toward the revolution in military affairs, the person who can see the data may be more important than the person who pulls the trigger. In the past, the person who pressed the button was the key piece of the entire system. I think in the future, it will be the person who sees everything who will be more important, and that’s why this technology is essential,” he contends.

Because the system is tailored for specific environments, customers must provide Lockheed Martin with their requirements so that the equipment can be designed to fulfill them. A spiral development model is being used because clients might re-evaluate their data needs after initial use of the system, Pickar shares.

A basic capability of LinkSensors could be deployed within six months of receiving a contract, he indicates. “It’s important to note that the specific customer requirements will drive the timing of the fielding. For example, a logical progression of development could start with the establishment of a common sensor database. This database could be accessed by disparate users who would use tailored applications to meet their particular information requirements.

“The database would also be the first step toward sensor management. Of course, the type of sensors and their level of sophistication will also determine the time it takes to field the system. The second developmental block could be the deployment of smart agent technology. Finally, the third step could be what I call echelon connectivity,” Pickar notes.

The company plans to have a demonstrator system completed during the first half of this year, and Pickar has been meeting with members of the U.S. Defense Department and the individual services about how LinkSensors could support their operations.


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