Study On Polar Format Algorithm For Monostatic/Bistatic SAR

Synthetic aperture radar(SAR)is a microwave imaging system which constructs an equivalent long antenna with signal processing technology.It can obtain two-dimensional high-resolution images in all day and all weather.Both in the field of military and civil,SAR has broad application prospect and huge development potential.Polar Format Algorithm(PFA)is a typical image formation algorithm for monostatic and bistatic spotlight SAR.It is based on planar wavefront assumption and corrects range cell migration(RCM)by two-dimensional interpolation before two-dimensional inverse fast fourier transformation(IFFT).PFA has very important significance in spotlight SAR system because of its simple procedure and high efficiency.This thesis made some further researches on PFA for monostatic and bistatic spotlight SAR.The main contributions are as follows:Chapter 1 outlined the development history of monostatic and bistatic SAR and presented the research background and main contents of this thesis.Chapter 2 introduced the principle of the conventional PFA for monostatic and bistatic spotlight SAR,simply analyzed the phase error induced by wavefront curvature and presented a more accurate derivation on the wavefront curvature.Chapter 3 further analyzed the procedure of range cell migration correction by two-dimensional interpolation from the viewpoint of two-dimensional signal decoupling.Proposed new formulations of PFA for monostatic and bistatic SAR and uncovered the essence of range and azimuth interpolation.Simulation data processing has verified the correctness of those new formulations.Chapter 4 put forward a fast polar format algorithm for variable-PRF monostatic and bistatic spotlight SAR.With this algorithm,a SAR image can be got by two-dimensional inverse fast fourier transformation after range resampling and keystone transformation.Compared with the conventional polar format algorithm,this algorithm can avoid one inserting processing and improve operation efficiency.The simulation results have verified the feasibility of this algorithm.Chapter 5 concluded the work of the whole thesis and pointed out the issues to be further studied.