Signal analysis of downward-looking and forward-looking array FMCW SAR

Downward-looking and Forward-looking (DL & FL) array Synthetic Aperture Radar (SAR) can image scene beneath and in front of the platform that can not be realized by side-looking (SL) SAR. According to curve sketch of equidistance and euqi-Doppler, blind zone beneath the platform and ambiguity symmetrical to the track of SL SAR are analyzed, and DL & FL array Frequency Modulated Continuous Wave (FMCW) SAR signal model is established. By virtue of signal model, expansions of range course in different forms are applied in analyzing Doppler characteristic and Range Cell Migration (RCM). Parameters affecting cross-track resolution, such as array length, target position and platform height are analyzed combing with effective array aperture. Simulation results show optimization and effectiveness of the parameters, which can provide reference for parameter design of array SAR.