Detection, Characterization and Mitigation of GNSS Jammers Using Windowed HHT

Nahal Fadaei, Ali Jafarnia-Jahromi, Ali Broumandan, and Gérard Lachapelle

Abstract:	Despite the fact that spread spectrum modulation provides some level of resistance against narrowband interference signals, satellite navigation signals are vulnerable to Radio Frequency Interferences (RFIs) such as spoofing and jamming. This paper investigates the effects of chirp-type in-car jammers on GNSS receivers and proposes methods to minimize their adverse effects on these devices. For jammer characterization, the Hilbert-Huang Transform (HHT) is employed as a counterpart to the well-known Short-Time Fourier Transform (STFT). A windowed-HHT method is proposed in order to reduce the complexity of the traditional HHT by decreasing the number of iterations in the signal decomposition section. Moreover, a Power-Law Detector (PLD) is embedded into the windowed-HHT to jointly detect and characterize the jammer. It is shown through extensive simulations that the accuracy of the proposed method is superior to STFT for different types of interference signals due to the adaptive nature of HHT and its independency on window size. The final stage is performed through a Fractional Fourier Transform (FrFT) time-frequency filtering to mitigate jammer signals. Real GPS data contaminated with different chirp-type jammers is used for performance assessment of the proposed methods. The analysis shows that the proposed structure is able to characterize and nullify the jammer effects successfully even for large jammer-to-noise ratio values.
Published in:	Proceedings of the 28th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2015) September 14 - 18, 2015 Tampa Convention Center Tampa, Florida
Pages:	1625 - 1633
Cite this article:	Fadaei, Nahal, Jafarnia-Jahromi, Ali, Broumandan, Ali, Lachapelle, Gérard, "Detection, Characterization and Mitigation of GNSS Jammers Using Windowed HHT," Proceedings of the 28th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2015), Tampa, Florida, September 2015, pp. 1625-1633.
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