3-D Imaging Research Of Alternating Spaceborne Bistatic Sar

Using highly accurate SAR images to get three dimensional image of targets have attracted more and more interest in recent years. In this paper, alternating bistatic SAR data is used to tomography three dimensional image. The use of compressed sensing algorithm to deal with space sparse and uneven baseline problem, traditional methods for solving demanding baseline arrangement insufficient to improve the practicality tomography has important practical significance.This paper focuses alternating bistatic SAR processing, including three dimensional model establishment, two dimensional imaging and three dimensional imaging based on compressing sensing. In this paper, the characteristics of bistatic SAR is analyzed, the problems in general configuration of bistatic SAR imaging and three-dimensional imaging are presented and been solved. Overall, the paper in the following aspects were studied and presented innovative approaches:1) Three-dimensional bistatic SAR signal model: in general configuration case, for example, establishing three dimensional bistatic SAR signal model, in which variables range and azimuth are analyzed.2) 2-D imaging of bistatic SAR: the transmitter and receiver are not in same platform, slant range is a form of double root, which is different from traditional single SAR, phase static point can’t get analytical solution. And if using the time domain algorithm, the calculation is too large and not suitable for the current practical needs. Inspiration from processing a fixed stop airborne bistatic SAR with Nonlinear CS imaging algorithm, the extended NLCS is used to processing bistatic SAR data. The experiment result shows that the image can be focused well by extended Nonlinear CS method.3) 3-D imaging of bistatic SAR: The traditional three-dimensional imaging data used are single radar navigation through multiple data, such data acquisition time is longer, but in the meantime the ground situation may have changed. And there are inconsistencies atmospheric phase, the time interval is too long resulting in weak correlation problem, and bistatic SAR provides different data sources. Bistatic SAR, especially alternating bistatic SAR, can provide richer SAR data in the short term, and also makes data acquisition cycle shorter. However, three-dimensional imaging bistatic SAR main problems is to build models, as well as baseline sparseness few times over the flight caused. Conventional tomography algorithms such as FFT algorithm, APES spectral estimation algorithm, require a uniform baseline, baseline sufficiently large number, it is clear that this will lead to higher costs, even not easy to achieve. Compressing sensing algorithm is used to solve imaging problem in different modes and three-dimensional imaging experiments are presented.