A Study on a Linear-Frequency-Modulation Interference Detection Algorithm for Single-Antenna Low-Earth-Orbit Signal-of-Opportunity Positioning Receivers

Signal-of-Opportunity (SOP) positioning based on Low-Earth-Orbit (LEO) constellation has become a research hotspot. Because of its large quantity, wide spectrum coverage and strong signal power, LEO satellite SOP signal has strong anti-jamming ability. However, there is still little research on anti-jamming technology for LEO satellite SOP signal positioning, especially for LFM interference. At present, it has not been deeply studied at home and abroad. Because of the great difference between the downlink signal of LEO satellite and the signal of Global Navigation Satellite System (GNSS) based on medium and high orbit, the research results of anti-jamming of traditional satellite guidance system can not be directly applied. In this paper, a Wigner-Ville distribution interference detection algorithm based on iterative signal cancellation (WVD-SIC) is proposed for LEO constellation signal with narrow downlink bandwidth and high landing signal-to-noise ratio (SNR). The algorithm eliminates the influence of strong signal power in input signal on Linear Frequency Modulation (LFM) interference detection by iterative fitting, and determines the characteristics of LFM interference signal by least square fitting. Finally, the improved performance of the algorithm is verified by simulation. The results show that compared with traditional algorithms, this method can effectively eliminate single/multi-component LFM interference, and improve the anti-jamming performance of LFM significantly in LEO satellite anti-jamming scene.