Study On Moving Target Imaging Methods For Narrowband Continuous Wave SAR

Traditional Synthetic Aperture Radar(SAR)imaging relies on wideband transformed waveforms.SAR using narrowband continuous waveforms(NCW)had been showed to achieve high resolution imaging exploiting high Doppler resolution.NCW-SAR has the following advantages: it occupies very small band resources;it promotes the development of low-cost and small SAR;it is much applicable to passive SAR using illumination sources of opportunity,because illumination sources of opportunity usually transmitts waveforms with narrow bandwidth.The thesis studies the NCW-SAR imaging of moving target.At first,the development of NCW-SAR imaging is reviewed and the status of NCW-SAR imaging technology is described in detail.A general radar received signal model of moving target suitable for describing the NCW-SAR received signal under “stop-go-stop” assumption is presented.On this basis,the thesis analyzes the NCW-SAR imaging method of moving targets using filter backprojection(FBP)in detail and gives the implementation algorithm to achieve to focus the moving targets on the ground scene.Then the moving target velocity estimation by the image contrast maximizing is proposed.And the image resolution analysis and the velocity resolution analysis are presented to reveal the parameters that affect the image reconstruction quality and the velocity estimation.By setting a variety of simulation configurations,we demonstrate the effectiveness of the presented NCW-SAR moving target imaging method and the velocity estimation method.Then,the thesis analyzes the NCW-SAR imaging artifacts due to the moving target based on microlocal analysis theory,and presents an explicit quantitative relationship between the hypothesized velocity errors of the target and the position errors in the reconstructed SAR image.The result is applicable to analyzing different moving target models artifacts in SAR imaging,estimating the trajectory errors,and is helpful for developing focus methods for the moving target and estimating target motion parameters.The thesis considers artifacts due to the moving target under the configuration of target velocity with fixed error.The simulation demonstrates the performance of theory analysis results.At the end,the work of the whole thesis is concluded.The issues to be studied next are pointed out.