The Algorithm Study Of The Range Multiple-transmitter-multiple-receiver Synthetic Aperture Ladar System For High-resolution And Wide-swath Imaging

At present,in the field of synthetic aperture laser radar imaging,SAL technology has some development in single-transmitter and single-receiver system,however,there is a restrictive relationship between azimuth high resolution and range wide swath.In practical applications,the single-transmitter and single-receiver SAL technology cannot meet the requirements.Therefore,in order to apply SAL technology in practice,the study of large swath imaging technology in SAL system is a problem that needs to be solved.But about the single-transmitter and single-receiver SAL technology,we cannot solve the problem just by changing some parametric or putting forward some relevant imaging algorithms.So,we consider a different transmission and receiver mode,the multi-transmitter and multi-receiver SAL technology,to solve the contradiction between the range swath and the azimuth resolution.In this thesis,we design the multi-transmitter and multi-receiver mode,and put forward a multi-transmitter and multi-receiver SAL imaging algorithm.The multi-transmitter and multi-receiver SAL technology works in the high pulse repetition frequency(PRF)mode.Based on the premise of azimuth high resolution,a lenticular lens is used to refract the divergence and focus characteristics,and the multi-channel technology is used to increase the beam width,which increase range swath.However,the range multi-transmitter and multi-receiver SAL system has the range overlapping problem in the echo signals.We can use the adaptive digital beamforming algorithm to obtain the range no-overlapping data.Then,we process the data to realize wide swath high-resolution imaging.The main contents of this thesis are: in Chapter II,the basic principle of SAL imaging is introduced.In the process of SAL imaging,it includes the working principle of SAL imaging,data receiving process,signal model,echo signal processing,and the range-Doppler algorithm in SAL imaging.In Chapter III,we introduce the contradiction between the range wide swath and azimuth resolution in the single-transmitter and single-receiver SAL imaging system,and then the range multi-transmitter and multi-receiver SAL technology to solve this contradiction problem by putting forward the echo signal model in the range multi-transmitter and multi-receiver SAL working system is directly introduced.In Chapter IV,an adaptive beamforming technique is proposed tosolve the overlapping problem and then we complete the subsequent SAL imaging algorithm,which achieve high-resolution wide swath imaging.Finally,the feasibility of the range multi-transmitter and multi-receiver SAL imaging is verified by using three-transmitter and three-receiver SAL imaging simulations.The main contribution and attempts of this thesis are:(1)To deal with the contradiction between the range swath and the azimuth resolution in single-transmitter and single-receiver SAL imaging,multi-transmitter and multi-receiver SAL working mode is putted forward.(2)The analysis of the gain matrix of the echo signal is performed in multi-transmitter and multi-receiver operation mode.(3)For the overlapping area problem of receiving signals from adjacent channels,the adaptive beamforming technology is proposed in the range multi-transmitter and multi-receiver SAL operation mode.