Airborne Bistatic Sar Motion Compensation Key Technologies

Airborne Bistatic Synthetic Aperture Radar (Bistatic SAR) operates with individual transmit and receive antennas which are mounted on separate platforms. Such a spatial separation has several operational advantages which will enhance the signature of stealthy targets, increase the capability and reduce the vulnerability in both military and civil usages. Researches on motion compensation technique are important parts of Bistatic SAR system design.The general bistatic geometry and signal models are given firstly. Based on these studies, the Doppler properties and resolutions are analyzed. The azimuth bandwidth and Doppler centroid frequency are related to the geometry models.The RD imaging algorithm of Bistatic SAR is discussed.It can only work on classical 2-order range model especially on the parallel model in broadside side-looking and stripmap.The character comparision of RD algorithm and BP algorithm is studied.The dissertation gives particularly empathies on motion error analysis. Motion error is given firstly.Theoretical analysis, simulation result show there kinds of typical motion errors'affection both on the flight course and on the line of sight (LOS).Both the phase error criterion and image criterions are compared , then important result is given.Both imaging algorithm and motion compensation need precise estimation of Doppler parameters. The dissertation analyzes traditional parameters estimation methods on parallel model.The character compensation of time-frequency analysis plus Radon transform method and the DCFT method is given.Motion compensation based on raw data is analyzed. The algorithm first makes use of the correlation method to estimate range immigration and then emends it in frequency-domain, at last executes the dechirp technique to compensate the phase.The relationship between the Doppler rate estimating precision and image quality is achieved.