Passive localization method for FH-OFDM signals based on passive synthetic aperture

Frequency hopping orthogonal frequency division multiplexing (FH-OFDM) signals are extensively utilized in Internet of Vehicles (IoV) and unmanned aerial vehicle (UAV) communication system which hold significant value in the area of passive location. However, traditional passive localization methods could not achieve high localization accuracy for FH-OFDM signals when the signal noise ratio (SNR) is low. Therefore, this paper proposes a high-accuracy passive localization method based on passive synthetic aperture (PSA) for FH-OFDM signals. The method begins by using repeated sequences to eliminate residual frequency offsets (RFO) through the least squares (LS) solution, followed by using pilots to remove the baseband modulation information. Subsequently, the doppler phase information of FH-OFDM signals is utilized to construct a cost function pertaining to the target position. After eliminating the Doppler phase in the azimuth domain through grid search, we can get peaks in the range domain through transformation. Finally, the target position is ascertained through peaks accumulation across all FH-OFDM signals. Simulation results verify that the proposed method can achieve meter-level high-accuracy location for FH-OFDM signals when SNR is low.