Application Of Synthetic Aperture Radar And Array In Three Dimensional Imaging

Three dimensional imaging radar system plays an irreplaceable role in the field of civil and military surveying and mapping.Three-dimensional synthetic aperture radar has the ability of three-dimensional imaging of the target for all day and all-weather.It has a unique advantage in the application fields such as ocean observation,environmental monitoring,disaster monitoring,agricultural assessment,resource exploration,geological surveying and military reconnaissance.It has come to the attention of researchers all over the world.In addition to the interference synthetic aperture radar technology that can extract the target elevation information,the array signal processing is a good solution to the 3D SAR imaging in synthetic aperture radar imaging,which can solve many problems.Therefore,the three-dimensional imaging technology of array synthetic aperture radar has high value of researching.The array signal processing method can be applied to the InSAR system in the side view mode and the three-dimensional imaging of the down view mode,and that technology in the InSAR system is called the multi baseline system.The two imaging modes are studied in this paper.In this paper,the basic principle and core technology of synthetic aperture radar imaging are introduced,and the geometric conformation model of SAR imaging is discussed.Besides the classical geometric configuration,the influence of attitude angle on the imaging region is also analyzed.The focusing algorithm of SAR imaging is studied.The two kinds of algorithms in frequency domain and time domain are discussed respectively.The advantages and disadvantages of each algorithm are analyzed.It is pointed out that in some cases,the time domain algorithm which is often ignored is still advantageous.Then the basic principle and processing flow of InSAR technology are studied,and the characteristics of InSAR interferometry are analyzed.Three kinds of common InSAR layover and shadow detection methods are discussed,their characteristics and advantages and disadvantages are analyzed,and the eigenvalue decomposition method based on multi baseline is improved.A set of joint estimation scheme is proposed in combination with the advantages of local frequency estimation,and its effectiveness is proved from the angle of error detection probability.The InSAR layover separation technology based on multi baseline and compressed sensing is studied.In addition to multi baseline InSAR and traditional DOA estimation,the compression sensing method can be introduced into the layover separation and based on the SAR image.In the assumption that the information structure of adjacent pixels is similar,two methods of using adjacent pixel data to realize the expansion of observation matrix(vector)are proposed,and the simulation experiments are carried out.It is proved that the improved method can get better estimation performance compared to the standard compression sensing method.Finally,the application of the down view array synthetic aperture radar in 3D imaging is studied,and the basic principle of the down view array synthetic aperture radar is introduced,and the three-dimensional resolution of the system is analyzed.Then the problem of optimization sparse for array is discussed.The optimization of random array and the application of the combined coprime array are studied.The simulation is carried out.It is proved that the result can get the lower sidelobe pattern by using the optimized equivalent direction matrix,and it is compared with the same physical element number.The rate of resolution is higher.The application of the downview array synthetic aperture radar in ice tomography is modeled,and an imaging scheme which combines the multi aperture back projection algorithm with the array signal direction estimation is proposed by using the combined coprime array.The advantages of the method are pointed out and the scene simulation is carried out,and the practicability of the scheme is proved.