Investigation of multichannel ScanSAR with up and down chirp modulation for range ambiguity suppression

According to echo model and properties of azimuth multichannel ScanSAR with up and down chirp modulation, an effective imaging approach to handle the raw data of this mode is proposed. First, echoes corresponding up and down chirp modulation pulses are individually range compressed. Afterwards, azimuth multichannel ScanSAR raw data with azimuth nonuniform sampling are reconstructed, and the resulting raw data are focused via the following modified Stolt interpolation and spectral analysis (SPECAN) steps. The effect on range ambiguity suppression of alternately sending up and down chirp signals is analyzed via simulation experiments on point and distributed targets. Simulation results validate the proposed imaging approach.