A Modified Fast Back-Projection Algorithm for mini-UAV-borne FMCW SAR Imaging

Frequency-modulation continuous-wave (FMCW) synthetic-aperture radar (SAR) is very suitable for installation on miniature unmanned aerial vehicle (UAV) due to its low power consumption and miniaturization. However, the large pulse width of its transmitted signal leads the "stop and go" assumption in the traditional pulsed radar is no longer valid. It is necessary to compensate the influence caused by intra pulse motion in imaging processing. The traditional BP algorithm is difficult to implement due to its high computational complexity. Fortunately, the fast BP (FBP) is a way to fix this problem. However, the intra pulse motion is not considered in the traditional FBP algorithm. This paper proposes a modified FBP algorithm to compensate the influence introduced by intra pulse motion of FMCW SAR. Firstly, the influence of intra pulse motion is discussed. Second, a modified FBP algorithm for compensating intra pulse motion is introduced. Finally, the results of simulation data experiments are presented to verify the effectiveness of the proposed algorithm.