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Sensors come of age in the business of
tracking dismounted warfighters

Becky Oh, President at PNI Sensor, talks to Soldier Mod about its FORT Field Ops Remote Tracker and why it is vital in mission-critical environments

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Precision is everything when it comes to mission-critical environments - including location and soldier tracking. Tracking a dismounted soldier's precise location, even when GPS is compromised or denied, is indispensable in today's successful war fighting efforts. Because getting that location wrong can have deadly consequences.

Historically, most sensor-based warfighter tracking systems have been dogged by problems stemming from sensor drift to magnetic interference and reliability. To deliver precise location data, modern sensor-based tracking systems must overcome these issues while providing a high-accuracy, low-power sensor module that delivers pinpoint accuracy wherever and whenever.

The new FORT (Field Ops Remote Tracker) does precisely this. FORT applies state-of-the-art technology to determine a soldier's precise location - even when GPS is compromised or denied. Created by PNI Sensor, FORT is a small, wearable device that provides 10 metre positional accuracy for every kilometre travelled - without the use of GPS or RF beacons.

In developing FORT's game-changing technology, PNI has leveraged years of industry leading research with precision location, motion tracking and fusion of sensor systems based on real-world applications. Applying learning from high-accuracy, low-power sensor fusion algorithms developed for wearables and smartphones has allowed us to create FORT's DST (Dismounted Soldier Tracking) location technology.

Unlike earlier sensor trackers, FORT's data remains accurate over time and in a wide range of conditions, delivering precise tracking in mission-critical scenarios. The use of Continually Adaptive Navigation algorithms (CAN), combined with advanced magnetometers, sophisticated gyros, accelerometers and Edge AI, eliminate sensor drift, magnetic interference and magnetic anomalies.

“FORT's fused sensors and algorithms allow it to track a dismounted soldier from an initial seed location to 1% location accuracy of their distance travelled over a 20-minute period without any additional GPS, location input or reliance on infrastructure,” explains PNI's Becky Oh. “For example, if a dismounted soldier were to travel 1km in any completely GPS-denied environment, the FORT will be able to track them to 10m positional accuracy.”

FORT works indoors or out, and is also field configurable and easily merged with an EUD (End User Device). By using a hardware platform that enables quick iteration, test and deployment, FORT is easily integrated with PNT and battlefield awareness systems. FORT also addresses key issues with GPS, reducing the vulnerabilities it can expose in certain environments. “GPS is amazing from the standpoint of accuracy, ubiquity and cost,” says Oh. “But fundamentally, it's still an RF technology, which makes it inherently fragile with inescapable vulnerabilities that are exploitable in conflict.”

“PNI's technology used doesn't just ensure accuracy, but it's also been designed to minimize weight and maximize portability,” Oh tells Soldier Modernisation. “The warfighter's load can add up to more than 68 pounds and in a combat mission, that weight can be as much as 120 pounds. Hence a low SWaP device such as FORT which only weighs 35 grams (inclusive of its internal rechargeable battery) is meaningful to a dismounted soldier.” FORT achieves this low SWaP by leveraging the innovation in gyroscopes, accelerometers, pressure sensors used in today's mobile phones along with PNI Sensor's more precise magnetometer. Of course, these sensors are algorithmically fused to extract performance from the combination of these sensors that far exceeds the performance of one sensor alone.”

PNI has over 30 years of experience in precision location, motion tracking and fusion of sensor systems into real-world applications, creating sensors and algorithms that have proved key to IoT projects and mission-critical applications where pinpoint location, accuracy and low power consumption are important.

PNI began working on GPS-denied tracking technology for the consumer market to enable location-based-services (LBS) for mobile phones. “In that application, the tracking was often referred to as indoor navigation (no GPS indoors) or Pedestrian Dead Reckoning (PDR) which tracked the mobile device user's location for marketing promotions,” explains Oh. “In that implementation, PNI did not have direct access to the sensors on the mobile phone but via the Android HAL (hardware abstraction layer) which was insufficient for running accurate sensor fusion. And we also could not choose the quality of the sensors native to the mobile device. This made it difficult to achieve the accuracy we currently achieve with the FORT. FORT uses best-in-class sensors, and we have complete control over the sensor data and the algorithms applied to them.” The technology also differs in that FORT is fully self-contained and does not rely on external infrastructure, unlike a mobile phone that often uses WiFi finger-printing, RF beacon data and contextual information. All useful in a civilian environment - but not necessarily available in certain tactical situations. “LBS is not a mission-critical service in the consumer market,” says Oh.

But tracking a warfighter in GPS-contested environments is indeed mission critical. In a battlefield, additional infrastructure such as WiFi fingerprinting or RF beacons are not available hence a self-contained sensor-only based tracking system such as FORT serves as a critical A-PNT (Assured Positioning Navigation and Timing) solution.” The multi-domain battlefield of 2030 and 2040 requires true resilience to EW (Electronic Warfare.) And even in the absence of EW, the warfighter already faces location and navigation challenges while operating in GPS-denied environments, including subterranean, underwater, tunnels, buildings, deep canyons and under heavy tree canopy. In these situations as well, FORT is an excellent A-PNT solution for the dismounted soldier.

The combination of pinpoint accuracy without reliance on GPS with a small, lightweight, easy-to-use tracker has upped the ante. Inertial navigation using inertial sensors such as gyroscopes, accelerometers and magnetometers has historically been used in aircraft and large vessels for navigation without GPS,” says Oh, “but their size, weight and expense makes them unsuitable for dismounted soldiers.” As a comparison, while inertial sensors used in traditional INS (Inertial Navigation Systems) are large and require a car battery to power them, FORT uses tiny, cellphone MEMS inertial sensors with PNI's magnetometers and is less than 3 x 5 x 1.2 cm.

“There have been other small tracking devices using consumer-grade sensors but they have not been accurate enough to be reliable in the field,” she told Soldier Mod. The FORT's proven performance in the field plus evaluations from various companies and agencies has led to the FORT being currently designed into a military EUD (End User Device). Working both as a supplement to or in place of GPS, PNI's FORT offers unrivalled position and tracking information and accuracy - even in situations where GPS is jammed, spoofed or denied.

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