Research On Synthetic Aperture Imaging Technology Of Multi-carrier Rader

As an important method of remote sensing and detection,synthetic aperture imaging plays a key role in both military and civilian fields.With the rapid development of SAR technology,the requirement of SAR image resolution is constantly increasing.This paper aims to research the related problems in synthetic aperture imaging of radar in multi-carrier signal form to effectively suppress the inter-range-cell interference.The main work is as follows:1.The basic technology of synthetic aperture imaging is researched,including the basic principles of SAR,the important parameters of synthetic aperture length,range resolution and azimuth resolution.The signal processing model is used to explain the working principle of synthetic aperture imaging.Range Doppler algorithm is introduced with simulation,and the estimation method of Doppler parameters is analyzed.2.The pulse compression technology in radar detection is studied,including the principle of pulse compression and the realization methods in time domain and frequency domain.The characteristics and problems of several common pulse compression signals are analyzed.Based on the OFDM technology in wireless communication and the related properties of Zadoff-Chu sequence,a multi-carrier modulation based pulse compression method is implemented and the ideal pulse compression effect of this method is verified by simulation.3.A cyclic prefix based OFDM technique is applied to radar imaging to implement a multi-carrier radar synthetic aperture imaging method.By studying the transmission and reception signal model,cyclic prefix length and discrete-time signal form,a multi-carrier signal model based on cyclic prefix is established,and the range processing method that can achieve an ideal pulse compression effect is analyzed.In addition,the effects of complex sequence for orthogonal multicarrier modulation and cyclic prefix length are discussed by simulation.4.A simulation scheme of multi-carrier SAR synthetic aperture imaging system is proposed.Based on the spatial geometric model of stripmap and vertical side-looking SAR,the echo signal model for simulation is established,and the simulation is implemented according to the imaging processing algorithm flow.By comparing the traditional LFM imaging method using RD algorithm and the OFDM imaging method with insufficient cyclic prefix,the imaging results are analyzed.