Research On Distributed SAR Imaging Based On Compressive Sensing

With people gradually rising the standards for radar imaging, the traditional singleSAR platform’s application limitations manifested gradually. Distributed SAR systemutilized multiple SAR platforms’collaboration, and could realize high-resolution, wide-swath imaging tasks while single SAR platform couldn’t achieve. However, thedistributed SAR system also faced conundrums like high-speed data acquisition,high-capacity data storage and transmission. Conventional CS radar imaging technologycould reduce the system’s sampling rate and the amount of echo data, but the imagingreconstruction efficiency was very low. Under this background, based on DCS theorywhich was derived from CS theory, this article launched a study on distributed SARsystem imaging technology based on DCS. The center contents are as follows:1. Radar imaging technology based on DCS is researched. According to thecharacteristics of radar echo data, the SAR imaging mathematics mode is constructedand a two-dimensional SAR imaging algorithm based DCS is presented which has goodimaging effect. Besides, with using the new algorithm, the amount of echo data andreconstruction time are both reduced.2. Azimuth multiple-beam SAR imaging technology based on DCS is researched.Signal model of distributed SAR system with single transmitter and multiple receiversis established. Under the guidance of equivalent phase center principle, equivalent echodata is got with phase compensation, and the resolution is improved with the spatialsampling increasing. Based on this, a novel multi-beam SAR imaging algorithm basedon DCS is proposed, it could realize compression and reconstruction in both rangedimension and azimuth dimension. Simulation results show that the algorithm has goodimaging effect. Besides, while comparing with CS imaging algorithm, the newalgorithm has better anti-noise performance and higher operating efficiency.3. Ambiguity resolving imaging technology of distributed SAR based on DCS isresearched. With using spatial filtering theory, echo data which the sparsely populateddistributed satellites received were eliminated ambiguity, and high-resolution imageswere got. Based on this, a novel distributed SAR ambiguity resolving imaging algorithm based on DCS is proposed which could achieve high-resolution imaging withusing little echo data. Besides, for analysising of noisy signal simulation, results showthat the new algorithm has higher efficiency and better reconstruction effect whilecomparing with CS algorithm.4. Spectrum synthesis imaging technology of distributed SAR based on DCS isresearched. From the standpoint of spreading spectrum, the reasons of different echodata’s frequency shift were analysed. With relative time-shift compensation and phasecompensation adding to echo data, broadening Doppler band was got and azimuthresolution was improved. Based on this, a novel distributed SAR spectrum synthesisimaging algorithm based on DCS was proposed. With DCS compress reconstruction inrange dimension, the algorithm effectively reduces the echo data and improves imagingefficiency.