Spectrum Reconstruction Algorithm for Multi-channel Non-uniformly Sampled SAR and Error Analysis

The SAR DPCMAB(Displaced Phase Centers Multiple Azimuth Beams mode) can increase the sampling rate in the azimuth direction,whereas, it brings the problem of non-uniform sampling. Using spectrum reconstruction algorithm can regain the spectrum of uniform sampling signal. However, as the influence of interferential factors produced during the operation of SAR system, such as channel characteristics inconsistency, sampling time deviation, random noise etc, spectrum noise is appended to the reconstruction spectrum resulting in the loss of reconstruction accuracy. The paper analyses the relationship between interference factors and reconstruction error by researching spectrum reconstruction of non-uniformly sampled LFM signals affected by interferential factors. Reconstructed spectrum influenced by interferential factors is obtained in the simulation. Further more, we present the relationship curve between spectral bias and interference factors. The simulation results show that the reconstruction errors grow linearly with the enhance of the interferential factors and approach to the spectral bias of non-uniformly sampled signal finally.