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Session D4: Anti-Jam and Anti-Spoofing Technologies 2

Field Demonstration of Spoofing-Resilient Dismounted PNT Using Inertial-Referenced GNSS Integrity Monitoring
George Hsu, PNI Sensor
Location: Room 1-3
Alternate Number 1

Robust, resilient, and assured position and navigation (PNT) are essential for dismounted warfighters operating in environments subject to deliberate GNSS spoofing and jamming, motivating the need for field-validated, sensor-fusion-based integrity monitoring approaches. This work presents the design, implementation, and APEX 2025 field results of FORT2, a self-contained assured PNT (A-PNT) system based on commercial off-the-shelf (COTS) sensors, developed to provide spoofing-resilient dismounted navigation in contested RF environments.
FORT2 is a compact, low-SWaP-C, body-worn device that tightly fuses inertial, magnetic, and GNSS measurements while continuously assessing GNSS signal integrity to distinguish spoofing, jamming, and benign signal occlusion. Rather than relying on GNSS-reported accuracy estimates—which are frequently compromised during spoofing—FORT2 derives inertial-referenced consistency and quality metrics to detect anomalous GNSS behavior and automatically reduces or rejects corrupted measurements. This integrity-driven fusion approach enables seamless transitions between fused and inertial-dominated navigation without operator intervention and requires no external infrastructure, survey data, or cooperative signals.
APEX 2025 testing was conducted over five days under active GNSS jamming and spoofing conditions, with four dismounted participants traversing approximately 116 km across multiple operationally relevant courses. During severe interference, GNSS-only solutions exhibited position errors ranging from hundreds to several thousand percent of distance traveled. In contrast, FORT2 maintained position errors below 1.0% of distance traveled for the vast majority of the test duration. FORT2 spoofing detection and integrity metrics demonstrated significant performance improvements relative to prior PNTAX 2024 results.
These results demonstrate that physics-based inertial reference and sensor-fusion integrity monitoring using COTS MEMS sensors can provide effective detection, rejection, and mitigation of GNSS spoofing, forming a resilient foundation for assured dismounted PNT. An emerging application of the FORT2 architecture—the Enhanced Pilot Locator Beacon (EPLB)—will also be presented, highlighting extension of this spoofing-resilient approach to personnel recovery missions in contested RF environments.

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