Session F2: Advanced Software and Hardware Technologies for GNSS Receivers

Array-Based GNSS Jamming Mitigation Using a Low-Cost Software-Defined Radio
Lasse Lehmann, Søren R. Larsen, Benjamin B. Elsholm, and Daniel H. Olesen, Technical University of Denmark, DTU Space
Location: Holiday 1 (Second Floor)
Date/Time: Wednesday, Sep. 10, 4:46 p.m.

Peer Reviewed

GNSS receivers are inherently vulnerable to interference owing to low-power GNSS signals. Mitigation strategies to ensure GNSS reception are numerous, yet few are as versatile as those based on antenna arrays. However, cost and size have been prohibitive to the widespread adoption of such techniques for typical receivers. KrakenSDR is an accessible multichannel software-defined radio (SDR) viable for localization and mitigating interference sources. While this SDR achieves phase synchronization across its array, array-based mitigation in the form of null steering may not fully apply out of the box, especially when using active GNSS antennas. This paper investigates the necessary calibration and implementation of null steering to perform jamming mitigation using KrakenSDR in real scenarios. The effects of null precision on null steering are studied via simulation to ensure adequate suppression. Calibration is performed using a known transmission source and evaluated for different approaches. The resulting calibration shows stark improvements to null steering, with the simpler single source performing better in generalizing across scenarios. The investigated techniques were tested for antenna array measurements subjected to realistic jamming conditions. Jamming detection evaluated on the captured data, subject to null steering, exhibits values consistent with the suppression of jamming. Although suppression is not absolute in the test scenario best resembling GNSS reception, further improvements are expected following planned calibration in future work.