﻿ 基于近程柱面SAR成像的改进距离徒动算法
 光学仪器  2020, Vol. 42 Issue (6): 9-14 PDF

Improved range migration algorithm based on short-range cylindrical SAR imaging
XIA Kewen, LI Ping
School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
Abstract: In order to improve the range migration algorithm (RMA) imaging efficiency of short-range cylindrical synthetic aperture radar (SAR) imaging and increase the application value of RMA in practical engineering, an improved RMA for SAR imaging is proposed. In this algorithm, the stationary phase method is used to obtain the phase compensation term in the wavenumber domain, which avoids the steps of angle dimension Fourier transform in the RMA of traditional short-range cylindrical SAR imaging, reduces the calculation amount and improves the imaging efficiency. The image quality of RMA was evaluated by peak-side lobe ratio (PSLR), peak signal to noise ratio (PSNR) and structural similarity (SSIM). Simulation and experimental results show that the algorithm improves the RMA imaging efficiency of short-range cylindrical SAR imaging.
Key words: cylindrical imaging    range migration algorithm(RMA)    synthetic aperture radar imaging    short range imaging    3D imaging

1 近程柱面SAR成像的改进RMA理论推导

 $s\left(\varphi ,{z}_{0},f\right)=\iiint \sigma (x,y,z){{\rm{e}}}^{-{\rm{j}}2kR}{\rm{d}}x{\rm{d}}y{\rm{d}}z$ (1)

 $R=\sqrt{{{(R}_{0}{\rm{cos}}\varphi -r{\rm{cos}}\theta )}^{2}+{{(R}_{0}{\rm{sin}}\varphi -r{\rm{sin}}\theta )}^{2}+{({z}_{0}-z)}^{2}}$ (2)
 图 1 近程柱面SAR的成像模型 Figure 1 Imaging model of short-range cylindrical SAR

 $R=\sqrt{{({R}_{0}-r)}^{2}+{rR}_{0}{(\theta -\varphi )}^{2}+{({z}_{0}-z)}^{2}}$ (3)

 $\begin{split} &s\left({k}_{\varphi },{k}_{{z}_{0}},k\right)=\\ &\iiint \left\{\iint \sigma (x,y,z){\rm{e}}^{-{\rm{j}}\left(2kR+{k}_{\varphi }\varphi +{k}_{{z}_{0}}{z}_{0}\right)}{\rm{d}}\varphi {\rm{d}}{z}_{0}\right\}{\rm{d}}x{\rm{d}}y{\rm{d}}z \end{split}$ (4)

 $s\left({k}_{x},{k}_{y},{k}_{z}\right)=\iiint \sigma (x,y,z){\rm{e}}^{-{\rm{j}}(\beta +{k}_{x}x+{k}_{y}y{+k}_{z}z)}{\rm{d}}x{\rm{d}}y{\rm{d}}z$ (5)

 $\beta ={R}_{0}\sqrt{4{k}^{2}-{k}_{z}^{2}-{k}_{\varphi }^{2}/({R}_{0}r})$ (6)

 $\beta ={R}_{0}\sqrt{4{k}^{2}-{k}_{z}^{2}-{2k}_{\varphi }^{2}/{R}_{0}^{2}}$ (7)

 ${\beta }'={-R}_{0}{\rm{cos}}\varphi {k}_{r}$ (8)

 $\sigma \left( {x,y,z} \right) = FD_{3{\rm{D}}}^{ - 1}\left\{ {FD_{1{\rm{D}}}^{ - 1}\left\{ {F{T_{2{\rm{D}}}}\left\{ {s\left( {\varphi ,{z_0},f} \right)} \right\}{{\rm{e}}^{ - {\rm{j}}\beta }}} \right\}} \right\}$ (9)

 图 2 iRMA与传统RMA流程对比图 Figure 2 Comparison of iRMA and traditional RMA processes
2 近程柱面SAR成像的改进RMA成像性能验证 2.1 仿真验证

 图 3 iRMA与RMA仿真结果对比图 Figure 3 Comparison of iRMA and RMA simulation results

2.2 实验验证

 图 4 实验场景 Figure 4 The tested object and the experimental scene

 图 5 iRMA与RMA实测成像结果 Figure 5 Comparison of iRMA and RMA measured imaging results

3 结　论

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