Study On Inverse Synthetic Aperture Radar Three-dimensional Imaging

Inverse synthetic aperture radar imaging can be divided into two types of2-D imaging and3-D imaging.In general,the two-dimensional imaging usesRange-Doppler imaging method,it gets range profile resolution and cross-rangeresolution by sending large broadband signal and the receiving back signalsDoppler frequency respectively,then we can get the target location informationby correction of back signals envelope alignment and initial phase.Envelopealignment is divided into cross-correlation method and the minimum entropymethod,the cross correlation method is a kind of the adjacent echo crosscorrelation to eliminate their envelope method,its disadvantage is that thecomputational cost is larger and cause the problem such as a suddenjump.Minimum entropy method is a method that combine the current back signalenvelope and back signal envelope earlier so that get synthesis echo envelopesummation, and the entropy for dimension synthesis echo envelope "sharpen"one way to achieve maximum, it can effectively solve the cross correlationmethod brings the envelope of drift error and kick.On the base of2-D imaging, this paper describes the method based on3-DISAR imaging of antenna array, compared with the conventional ISAR imagingusing three different antennas, the method is obtained target location informationby using two vertical antenna arrays,it can improve the ability to distinguish theradar scattering points. Then the imaging method based on two condition-thespecific imaging of isolated points and complex scattering point algorithm isproposed.Translation and radial motion compensation at the same time if isolatedscattering point,otherwise, must be compensated separately. Then for the twocases above imaging simulation and gives the corresponding analysis results, thismethod can get good imaging effects but step complicated computation anderror-prone.In order to improve the above algorithm,I proposed based on2-D sparsearray of three-dimensional InISAR imaging algorithm,the algorithm employssparse array,it simplifies the actual difficulties and reduce the complexity of thealgorithm on the basis of guarantee the quality of imaging greatly,then put zeropadding method, window function method and matched filtering method andother image processing methods in it, it can improved imaging effect and imagequality. Finally, simulation is carried out for the above parts, the results showthat joined the zero padding and matched filter optimization method based ontwo-dimensional image sparse array of3-D imaging can improve image quality and reduce the computation complexity and get good imaging effects.