A Pre- and Post-correlation Comparative Analysis to Assess Resilience Against Jamming for GNSS Space Receivers

Sahana Bandagadde Umesha, Clovis Maia, Mohamed Bochkati, Jürgen Dampf, Thomas Pany

Abstract: GNSS receivers deployed on satellites are increasingly vital, offering autonomy in navigation and cost-effective timekeeping. The growth of Low Earth Orbit (LEO) satellite constellations providing Position Navigation and Timing (PNT) services has made GNSS space receivers a preferred alternative to atomic clocks, significantly improving operational efficiency. However, the rising threat of Radio Frequency (RF) jamming by mobile military platforms poses a significant challenge to LEO satellite missions relying on precise positioning. To address this threat, designing sophisticated tracking loops within onboard GNSS receivers capable of resisting interference while ensuring precise positioning is essential. While orbit filters have contributed to high-precision GNSS receivers, research on jamming in this context remains limited due to the scarcity of signal samples from LEO satellites, constrained by bandwidth limitations. Consequently, GNSS signal compression plays a pivotal role in overcoming these constraints. This paper builds upon the work of Bochkati et al. (2022), introducing a technique for generating GNSS signal Multi-Correlator (MC) values for efficient data compression. We apply this tool to a specific use case, the Seamless Radio Access Networks for the Internet of Space (SeRANIS) mission, which relies on precise orbit positioning in LEO and uplink transmission of stored GNSS signals. By employing our data compression tool alongside a MATLAB software receiver (MSRx), we analyze interference signals on a simulated GNSS space receiver within the SeRANIS mission, assessing its robustness against jamming in both aided and non-aided tracking loop conditions. Two methods for simulating GNSS signal interference are established: (i) interference embedded within a pre-processed GNSS signal and (ii) interference added directly at the MC post-correlation level, impacting correlation values of a formerly clean GNSS signal. The study utilizes Rohde and Schwarz SMW200A vector signal generator and SX3 frontend for signal generation and RF data capture. Aided tracking loops are established using reference trajectory data, closely simulating true carrier-aiding information. Various interference scenarios, including Broadband Gaussian Noise Interference (BBI) and Continuous Wave (CW) interference, are investigated. Analysis measures, such as code and carrier discriminators, residuals, effective C/N0, and Position Velocity and Time (PVT) solution accuracy, are employed to assess their effects. Our results demonstrate consistent robustness against jamming in aided-tracking loop scenarios, comparing the effectiveness of Doppler-carrier-aiding under diverse jamming conditions. In addition to enhancing resilience in GNSS space receivers, our approach enables novel and flexible interference simulations at the post-correlation level, eliminating the need to reproduce the entire signal correlation chain while testing various integration algorithms.
Published in: Proceedings of the 36th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2023)
September 11 - 15, 2023
Hyatt Regency Denver
Denver, Colorado
Pages: 1544 - 1564
Cite this article: Umesha, Sahana Bandagadde, Maia, Clovis, Bochkati, Mohamed, Dampf, Jürgen, Pany, Thomas, "A Pre- and Post-correlation Comparative Analysis to Assess Resilience Against Jamming for GNSS Space Receivers," Proceedings of the 36th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2023), Denver, Colorado, September 2023, pp. 1544-1564. https://doi.org/10.33012/2023.19387
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