Performance Analysis and Image Formation Algorithm for Helicopter-borne Rotating Synthetic Aperture Radar

A novel helicopter-borne Frequency Modulated Continue Wave (FMCW) ROtating Synthetic Aperture Radar (ROSAR) imaging method is proposed. Firstly, by performing the equivalent phase center principle, the separated transmitting and receiving antenna system is equalized to the case of system configuration with antenna both for transmitting and receiving signals. Based on this, accurate two-dimensional spectrum is obtained and the Doppler frequency shift effect induced by the platforms continuous motion while radar transmits and receives signals is analyzed in detail and compensated. Then, efficient inverse Chirp-Z transform is applied to correct the range-variant Range Cell Migration (RCM). With only FFT and complex multiplication and no interpolation, the proposed method can be efficiently implemented. Finally, correctness of the analysis and effectiveness of the proposed algorithm are demonstrated through simulation results.