Research On Near - Field Planar Scattering Imaging Algorithm For Millimeter Wave Radar

As a kind of ultra wideband radar signal whose frequency changes by step, Stepped-Frequency (SF) pulse signal has been widely used in the field of radar imaging and target identification, etc. This paper studied the millimeter wave SF pulse radar imaging algorithm based on short-range plane scanning.Firstly, the paper introduces the basic principle of radar scattering imaging. It describes imaging principle of Synthetic Aperture Radar and deducts the radar resolution on this condition. Meanwhile, scattering centre of Radar Cross Section (RCS) and the essence of RCS imaging is discussed. In the end, wideband high-resolution radar technology, including SF pulse signal, is introduced.Secondly, this paper studies radar imaging algorithms of one-dimension distance imaging, two-dimension imaging, including coranal section and transverse section, and three-dimension imaging, focusing on zero padding algorithm to improve the display resolution of one-dimension distance imaging, and Stolt intepolation algorithm in two-dimension transverse section imaging and three-dimension imaging. Moreover, truncated sine intepolation algorithm and cellular intepolation algorithm to realize Stolt intepolation are compared in this paper that points out the applicable occasion of each algorithm.Thirdly, aming at the disadvantages that traditional two-dimension transverse section imaging and three-dimension imaging algorithms based on Stolt interpolation have high computational complexity, the paper studies imaging algorithm base on Non-Uniform Fast Fourier Transform (NUFFT). Meanwhile, according to different reffered data model, the algorithms of two-dimension transverse section imaging and three-dimension imaging based on NUFFT are improved. In addition, time complexity of NUFFT algorithm is analyzed and compared with traditional Stolt interpolation algorithm.Finally, facing the condition that radar sampling data is missing or Nyquist rate cannot be satisfied, this paper uses Compressive Sensing (CS) theory to solve the problem. Furthermore, during CS sparse scene imaging, the paper adopts two down-sampling methods to realize random frequency short-range imaging. The comparison of them and traditional imaging argorithm on imaging effect is made in detail.