Artifacts in Radar Imaging of Moving Targets

In this thesis, we study the artifacts that occur when a scene being imaged by radar contains moving targets. The physics of interaction between radar waves and moving targets were studied to develop a model using MATLAB for the received signal which does not make use of the start-stop approximation. The effects of target motion in the image formation process were studied for different radar configurations, including multistatic radars and Synthetic Aperture Radar. The key limitation of this model is its high computational resource requirements when simulating high bandwidth or long pulses. It was observed that range profiles may experience distortion due to the received waveforms differences from the matched filter. The exact outcome is waveform dependent; generally, both main lobe broadening and range errors were introduced by target motion. This leads to the wrong object localization and defocusing on the image. For SAR, a moving targets physical location varies throughout the imaging process. This means that standard backprojection fails to yield a focused image even if the range error due to the Doppler shift has been corrected, resulting in smearing. This is similar to motion blur experienced in optical cameras with a fast object.http://archive.org/details/artifactsinradar1094517470Civilian, Defence Science & Technology Agency, SingaporeApproved for public release; distribution is unlimited