分布式SAR环境下GMTI关键技术的研究
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摘要
二十世纪九十年代美国提出了一种新的天基SAR体制——分布式SAR或星座SAR,这种雷达体制立即成为SAR领域研究新热点,受到世界各个国家的重视。这种雷达体制在理论上可以克服当前合成孔径雷达不可逾越的困难:无法同时获得宽测绘带和高分辨率SAR图像;SAR-GMTI过程中不能获得足够长的天线孔径以满足最小可检测速度的要求;SAR干涉测高不能有足够长的空间基线以满足人们需要的测高精度或则不能得到相关性足够好的干涉数据。而分布式SAR可以在单行过的情况下同时获得宽测绘带和高分辨率图像,以及得到长的多空间基线进而可以得到高的测高精度并满足最小可检测速度的要求。但是分布式SAR面临很多实现上的困难,例如空间阵列超稀疏分布、回波信号存在距离或/和多普勒模糊、存在阵列位置(基线)测量误差、发射功率限制等等。目前尚无在运行的分布式SAR系统,所以必须克服这些困难才能把这种雷达体制由理论变为工程实践。
本文研究了分布式SAR动目标检测系统的实现问题。主要内容可以归纳如下:
(1)介绍了SAR的基本原理和成像算法,包括合成孔径原理和当前常用的雷达成像算法(RD算法、CS算法、NCS算法)。分别利用RD算法、CS算法进行点目标成像仿真和机载SAR雷达真实数据成像,然后仿真了NCS算法点目标成像。研究了SAR动目标的的回波特性,分析了动目标对SAR回波多普勒中心频率和多普勒调频率的影响以及对成像结果的影响。
(2)研究了如何仿真分布式SAR回波数据。首先研究了SAR面目标回波模拟的问题,从时域法和频域法分别对SAR面目标回波数据模拟进行了仿真。因为时域法是描述了SAR系统接收回波过程的方法,因此利用时域法进行了分布式SAR回波模拟。同时提出了一种基于空间非同时采样原理的分布式SAR回波模拟方法,并将动目标回波数据叠加到这种方法模拟的回波数据中,得到了含有动目标的分布式SAR回波数据。
(3)研究了多通道多像素联合动目标检测方法。因为基于空间非同时采样原理仿真的分布式SAR回波数据具有较高的相关性,因此利用该数据进行动目标检测处理。多通道多像素联合动目标检测是一种在图像域检测动目标的STAP算法。利用多个通道的多个像素构造杂波协方差矩阵,并利用最优空时自适应原理构造滤波权值,最后进行最优滤波并得到动目标检测结果。
A new space-borne SAR system—Distributed SAR or Constellation SAR was put forward by the United States in the 1990s. This SAR system immediately became a new research hotspot of the radar domain, and was emphasized all around the world. In theory, this radar system could overcome the insurmountable difficulties of the traditional SAR system: The traditional SAR cannot acquire wide swath and high resolution SAR image simultaneously; The traditional SAR-GMTI system cannot acquire long enough baseline to meet the requirement of minimum detectable velocity; The traditional InSAR system cannot acquire long enough space baseline to meet the requirement of height measurement accuracy or cannot obtain high related interferometry data. Distributed SAR could acquire wide swath and high resolution SAR simultaneously and acquire higher height measurement accuracy and lower minimum detectable velocity at single pass. But there are many difficulties to solve to realize the Distributed SAR system, such as highly sparse array distribution, Range and/or Doppler blur of echo signal, baseline measurement error of distributed array, transmitting power limit. There is not Distributed SAR system at work at present, so we have to overcome these problems to translate the theoretical system to engineering realization.
In this master thesis, Ground Moving Target Indication is studied for Distributed SAR system. The main results of this thesis are listed as follows.
(1) This dissertation introduced the basic theory and imaging algorithm, consisting of the principle of synthetic aperture and SAR imaging algorithm(RD algorithm, CS algorithm, NCS algorithm); Simulated a point target SAR raw data at side looking mode and deal it with RD algorithm and CS algorithm; Simulated a point target SAR raw data at squint mode and deal it with NCS algorithm. And deal the real airborne SAR data with RD algorithm and CS algorithm. The echo character of SAR moving target was researched, consisting of the influence of SAR moving target to the Doppler center frequency and Doppler modulation frequency of SAR echo and to SAR image.
(2) This paper researched the method of simulating the raw echo data of Distributed SAR. Firstly, the method of simulating SAR real scene raw signal was researched. SAR real scene raw data was simulated with the time domain method and the frequency domain method. Then used the time domain method simulating the Distributed SAR real scene raw data for the dealing process of the time domain method being analogous to the real SAR process of transmitting and receiving signal. The dissertation put forward a method of simulating Distributed SAR based on the non-simultaneous space-time samples, and synthesized this data and the moving point target raw data to get the Distributed SAR real data containing moving target.
(3) The dissertation researched the multi-channel and multi-pixel adaptive signal processing in image domain. Here we used the simulated raw data based on the non-simultaneous space-time samples to simulate the process of Ground Moving Target Indication for the raw data of different SAR being high related. The multi-channel and multi-pixel adaptive signal processing use the multi-pixel of multi-channel construct the clutter covariance matrix and use the principle of optimal space time adaptive processing and spatial steering vector to construct filtering weight and get the result of GMTI.
本文研究了分布式SAR动目标检测系统的实现问题。主要内容可以归纳如下:
(1)介绍了SAR的基本原理和成像算法,包括合成孔径原理和当前常用的雷达成像算法(RD算法、CS算法、NCS算法)。分别利用RD算法、CS算法进行点目标成像仿真和机载SAR雷达真实数据成像,然后仿真了NCS算法点目标成像。研究了SAR动目标的的回波特性,分析了动目标对SAR回波多普勒中心频率和多普勒调频率的影响以及对成像结果的影响。
(2)研究了如何仿真分布式SAR回波数据。首先研究了SAR面目标回波模拟的问题,从时域法和频域法分别对SAR面目标回波数据模拟进行了仿真。因为时域法是描述了SAR系统接收回波过程的方法,因此利用时域法进行了分布式SAR回波模拟。同时提出了一种基于空间非同时采样原理的分布式SAR回波模拟方法,并将动目标回波数据叠加到这种方法模拟的回波数据中,得到了含有动目标的分布式SAR回波数据。
(3)研究了多通道多像素联合动目标检测方法。因为基于空间非同时采样原理仿真的分布式SAR回波数据具有较高的相关性,因此利用该数据进行动目标检测处理。多通道多像素联合动目标检测是一种在图像域检测动目标的STAP算法。利用多个通道的多个像素构造杂波协方差矩阵,并利用最优空时自适应原理构造滤波权值,最后进行最优滤波并得到动目标检测结果。
A new space-borne SAR system—Distributed SAR or Constellation SAR was put forward by the United States in the 1990s. This SAR system immediately became a new research hotspot of the radar domain, and was emphasized all around the world. In theory, this radar system could overcome the insurmountable difficulties of the traditional SAR system: The traditional SAR cannot acquire wide swath and high resolution SAR image simultaneously; The traditional SAR-GMTI system cannot acquire long enough baseline to meet the requirement of minimum detectable velocity; The traditional InSAR system cannot acquire long enough space baseline to meet the requirement of height measurement accuracy or cannot obtain high related interferometry data. Distributed SAR could acquire wide swath and high resolution SAR simultaneously and acquire higher height measurement accuracy and lower minimum detectable velocity at single pass. But there are many difficulties to solve to realize the Distributed SAR system, such as highly sparse array distribution, Range and/or Doppler blur of echo signal, baseline measurement error of distributed array, transmitting power limit. There is not Distributed SAR system at work at present, so we have to overcome these problems to translate the theoretical system to engineering realization.
In this master thesis, Ground Moving Target Indication is studied for Distributed SAR system. The main results of this thesis are listed as follows.
(1) This dissertation introduced the basic theory and imaging algorithm, consisting of the principle of synthetic aperture and SAR imaging algorithm(RD algorithm, CS algorithm, NCS algorithm); Simulated a point target SAR raw data at side looking mode and deal it with RD algorithm and CS algorithm; Simulated a point target SAR raw data at squint mode and deal it with NCS algorithm. And deal the real airborne SAR data with RD algorithm and CS algorithm. The echo character of SAR moving target was researched, consisting of the influence of SAR moving target to the Doppler center frequency and Doppler modulation frequency of SAR echo and to SAR image.
(2) This paper researched the method of simulating the raw echo data of Distributed SAR. Firstly, the method of simulating SAR real scene raw signal was researched. SAR real scene raw data was simulated with the time domain method and the frequency domain method. Then used the time domain method simulating the Distributed SAR real scene raw data for the dealing process of the time domain method being analogous to the real SAR process of transmitting and receiving signal. The dissertation put forward a method of simulating Distributed SAR based on the non-simultaneous space-time samples, and synthesized this data and the moving point target raw data to get the Distributed SAR real data containing moving target.
(3) The dissertation researched the multi-channel and multi-pixel adaptive signal processing in image domain. Here we used the simulated raw data based on the non-simultaneous space-time samples to simulate the process of Ground Moving Target Indication for the raw data of different SAR being high related. The multi-channel and multi-pixel adaptive signal processing use the multi-pixel of multi-channel construct the clutter covariance matrix and use the principle of optimal space time adaptive processing and spatial steering vector to construct filtering weight and get the result of GMTI.
引文
1刘颖.分布式SAR运动目标检测雷达阵列误差估计方法研究.西安电子科技大学博士论文. 2007: 1~50
2 Linnehan, Robert, Perlovsky, Mutz. Detecting multiple slow-moving targets in SAR images, Sensor array and multichannel signal processing workshop. 2004: 643~647
3 Fola, David, Newman. Design and implementation of satellite formations and constellations. Advances in the Astronautical Sciences. 1998, 100(1): 57~70
4 W. H. Clohessy, R. H. Wiltshire. Terminal guidance system for satellite rendezvous. Journal of Aerospace Sciences, 1960, 27: 653~658
5江碧涛.分布式雷达成像及地面运动目标检测方法研究.中国科学院研究生院博士学位论文. 2007: 1~10
6王彤,保铮,廖桂生.天基分布式雷达GMTI方法.电子学报. 2006, 34(3): 399~403
7 Sherwin, C. W. P. Ruina, and R. D. Rawcliffe. Some early development in synthetic aperture radar systems. IRE Trans. MIL, 1962, 6: 111~115
8 Giorgio Franceschetti, Riccardo lanari. synthetic aperture signal processing. CRC Press, Inc. 1999
9 Werner, M. Shuttle radar topography mission (SRTM): experience with the X-band SAR interferometer radar. 2001 CIE International Conference on Signal Proceedings. 2001: 634~638
10 Martin M., and Stallard, M. Distributed satellite missions and technologies-The TechSat 21 program. Peoceedings of the AIAA Space Technology Conference and Exposition, Albuquerque, NM, Sept. AIAA. 1999, 99~4499
11 Burns R., et al. TechSat 21: Formation design, control , and simulation, Proceedings of IEEE Aerospace Conference, Big Sky, MT, Piscataway: IEEE Press. 2000: 19~25
12 Didier Massonnet. Capabilities and limitations of the interferometric cartwheel. IEEE Trans, On Geoscience and Remote Sensing. 2001, 39(3) : 506~520
13保铮,邢孟道,王彤.雷达成像技术.电子工业出版社. 2008:47~65
14 Van Trees H L. Optimum array processing. New York: John Wiley & Sons, Inc. 2002
15 Soumekh M. Synthetic aperture radar signal processing. New York: John Wiley & Sons ,INC. 1999
16 John C C, Robert N M. Synthetic aperture radar system and signal processing. New York: John Wiley & Sons, INC. 1999
17 Mehrdad Soumekh. Synthetic aperture radar signal processing with MATLABalgorithms. John Wiley & Sons, Inc., 1999
18 Raney R K, Runge H, Bamler R, et al. Precision SAR processing using chirp scaling. IEEE Trans. On GRS. 1994, 32(7): 786~799
19 Davidson G W, Cumming I G, Ito M R. A chirp scaling approach for processing squint model SAR data. IEEE Trans. On AES, 1996, 32(1)
20程玉平.一种改进的非线性CS成像算法.西安电子科技大学学报. 2000, 27(3): 273~277
21赵青.合成孔径雷达目标回波数据模拟方法研究.哈尔滨工业大学硕士论文, 2006: 1~28
22陈培群.利用大阵变小阵提高STAP在多通道SAR-GMTI中的性能.电子科技, 2008, 21(11): 20~251
23保铮.对于分布式小卫星群天基雷达信号处理一些基本问题的思考.第九届全国雷达学术年会论文集. 2004
24张璘.基于实测数据的记载SAR成像算法研究.哈尔滨工业大学硕士论文. 2007: 64~69
25王力宝,贺照辉,赵红军. SAR分布目标原始回波数据模拟.空军雷达学院学报. 2006, 20(2): 94~97
26张洪欣,张成亮.基于复杂真实场景的合成孔径雷达原始回波数据的一种模拟方法.现代电子技术. 2001: 25~29
27段秋萍,董戈,祁海明.基于真实场景的SAR回波模拟方法研究.遥测遥控. 2007. 28(3): 35~40
28霍耀,宋元鹤,张群,何元桥. SAR场景目标原始回波数据仿真.导弹与制导学报. 2008, 28(6):2 66~269
29李凌杰,王建国,黄顺吉.基于真实反射场景的SAR原始回波数据模拟.电子科技大学学报. 1996, 25(6): 566~568
30张澄波.综合孔径雷达原理、系统分析与应用.科学出版社. 1989
31郑明洁.合成孔径雷达动目标检测和成像研究.中国科学院研究生院博士论文. 2003: 9~2003
32李杰,向敬成,黄顺吉.合成孔径雷达慢动目标成像处理的研究.电子科技大学学报. 1995, 24(2): 119~125
33刘永坦.雷达成像技术.哈尔滨工业大学出版社. 1999: 1~116
34 Coe, D.J. and White, R.G. Moving Target detection in SAR imagery: experimental results, Record of the IEEE 1995 International Radar Conference. 1995: 644~649
35 F. K. Li, D. N. Held, J. Curlander. Doppler parameter estimation for spaceborne synthetic aperture radar. IEEE Trans. On GRS. 1985: 47~55
36 J. Siewerth. Theory and quantitative comparison of doppler centriod estimation methods. In Proc. of IGARSS’89 Symposium. 1989
37 Wang, et al. Mainlobe clutter cancellation by DPCA for space-based radars. Aerospace Applications Conference. 1991:112~128
38 Chapin Elaine, Chen curtis W. GMTI along-track interferometry experiment. IEEE Aerospace and Electronic Systems Magazine. 2006, 21(3): 15~20
39 R Klemm. Introduction to Space-time Adaptive Processing. Electronics & Communication Engineering Journal. 1999, 2: 5~12
40 William L. Melvin. A STAP overview. IEEE A & E System Magazine, 2004, 19(1): 19~35
41 Zebker H A, Villasenor J. Decorrelation in interferometric radar echos. IEEE Trans on Geosci Remote Sensing, 1992, 30(5): 950~959
42周争光,廖桂生,李海,刘颖.一种新的多通道SAR地面动目标检测定位方法.系统工程与电子技术. 2008,30,(5):819~823
43周争光,廖桂生.基于联合特征导向矢量的多通道SAR地面动目标检测定位.西安电子科技大学学报. 2008, 35(5): 585~863
44常玉林,黄晓涛,周红,周智敏.多通道SAR图像域STAP方法.遥感学报. 2009: 238~245
45蔚婧,廖桂生,曾操.基于协方差矩阵特征分解的多通道SAR-GMTI方法及性能分析.电子与信息学报. 2009, 31,(2): 374~377
46李真芳,保铮.基于图像的分布式星载InSAR地面动目标检测方法.分布式小卫星雷达地面动目标指示会论文集. 2005: 72~78
2 Linnehan, Robert, Perlovsky, Mutz. Detecting multiple slow-moving targets in SAR images, Sensor array and multichannel signal processing workshop. 2004: 643~647
3 Fola, David, Newman. Design and implementation of satellite formations and constellations. Advances in the Astronautical Sciences. 1998, 100(1): 57~70
4 W. H. Clohessy, R. H. Wiltshire. Terminal guidance system for satellite rendezvous. Journal of Aerospace Sciences, 1960, 27: 653~658
5江碧涛.分布式雷达成像及地面运动目标检测方法研究.中国科学院研究生院博士学位论文. 2007: 1~10
6王彤,保铮,廖桂生.天基分布式雷达GMTI方法.电子学报. 2006, 34(3): 399~403
7 Sherwin, C. W. P. Ruina, and R. D. Rawcliffe. Some early development in synthetic aperture radar systems. IRE Trans. MIL, 1962, 6: 111~115
8 Giorgio Franceschetti, Riccardo lanari. synthetic aperture signal processing. CRC Press, Inc. 1999
9 Werner, M. Shuttle radar topography mission (SRTM): experience with the X-band SAR interferometer radar. 2001 CIE International Conference on Signal Proceedings. 2001: 634~638
10 Martin M., and Stallard, M. Distributed satellite missions and technologies-The TechSat 21 program. Peoceedings of the AIAA Space Technology Conference and Exposition, Albuquerque, NM, Sept. AIAA. 1999, 99~4499
11 Burns R., et al. TechSat 21: Formation design, control , and simulation, Proceedings of IEEE Aerospace Conference, Big Sky, MT, Piscataway: IEEE Press. 2000: 19~25
12 Didier Massonnet. Capabilities and limitations of the interferometric cartwheel. IEEE Trans, On Geoscience and Remote Sensing. 2001, 39(3) : 506~520
13保铮,邢孟道,王彤.雷达成像技术.电子工业出版社. 2008:47~65
14 Van Trees H L. Optimum array processing. New York: John Wiley & Sons, Inc. 2002
15 Soumekh M. Synthetic aperture radar signal processing. New York: John Wiley & Sons ,INC. 1999
16 John C C, Robert N M. Synthetic aperture radar system and signal processing. New York: John Wiley & Sons, INC. 1999
17 Mehrdad Soumekh. Synthetic aperture radar signal processing with MATLABalgorithms. John Wiley & Sons, Inc., 1999
18 Raney R K, Runge H, Bamler R, et al. Precision SAR processing using chirp scaling. IEEE Trans. On GRS. 1994, 32(7): 786~799
19 Davidson G W, Cumming I G, Ito M R. A chirp scaling approach for processing squint model SAR data. IEEE Trans. On AES, 1996, 32(1)
20程玉平.一种改进的非线性CS成像算法.西安电子科技大学学报. 2000, 27(3): 273~277
21赵青.合成孔径雷达目标回波数据模拟方法研究.哈尔滨工业大学硕士论文, 2006: 1~28
22陈培群.利用大阵变小阵提高STAP在多通道SAR-GMTI中的性能.电子科技, 2008, 21(11): 20~251
23保铮.对于分布式小卫星群天基雷达信号处理一些基本问题的思考.第九届全国雷达学术年会论文集. 2004
24张璘.基于实测数据的记载SAR成像算法研究.哈尔滨工业大学硕士论文. 2007: 64~69
25王力宝,贺照辉,赵红军. SAR分布目标原始回波数据模拟.空军雷达学院学报. 2006, 20(2): 94~97
26张洪欣,张成亮.基于复杂真实场景的合成孔径雷达原始回波数据的一种模拟方法.现代电子技术. 2001: 25~29
27段秋萍,董戈,祁海明.基于真实场景的SAR回波模拟方法研究.遥测遥控. 2007. 28(3): 35~40
28霍耀,宋元鹤,张群,何元桥. SAR场景目标原始回波数据仿真.导弹与制导学报. 2008, 28(6):2 66~269
29李凌杰,王建国,黄顺吉.基于真实反射场景的SAR原始回波数据模拟.电子科技大学学报. 1996, 25(6): 566~568
30张澄波.综合孔径雷达原理、系统分析与应用.科学出版社. 1989
31郑明洁.合成孔径雷达动目标检测和成像研究.中国科学院研究生院博士论文. 2003: 9~2003
32李杰,向敬成,黄顺吉.合成孔径雷达慢动目标成像处理的研究.电子科技大学学报. 1995, 24(2): 119~125
33刘永坦.雷达成像技术.哈尔滨工业大学出版社. 1999: 1~116
34 Coe, D.J. and White, R.G. Moving Target detection in SAR imagery: experimental results, Record of the IEEE 1995 International Radar Conference. 1995: 644~649
35 F. K. Li, D. N. Held, J. Curlander. Doppler parameter estimation for spaceborne synthetic aperture radar. IEEE Trans. On GRS. 1985: 47~55
36 J. Siewerth. Theory and quantitative comparison of doppler centriod estimation methods. In Proc. of IGARSS’89 Symposium. 1989
37 Wang, et al. Mainlobe clutter cancellation by DPCA for space-based radars. Aerospace Applications Conference. 1991:112~128
38 Chapin Elaine, Chen curtis W. GMTI along-track interferometry experiment. IEEE Aerospace and Electronic Systems Magazine. 2006, 21(3): 15~20
39 R Klemm. Introduction to Space-time Adaptive Processing. Electronics & Communication Engineering Journal. 1999, 2: 5~12
40 William L. Melvin. A STAP overview. IEEE A & E System Magazine, 2004, 19(1): 19~35
41 Zebker H A, Villasenor J. Decorrelation in interferometric radar echos. IEEE Trans on Geosci Remote Sensing, 1992, 30(5): 950~959
42周争光,廖桂生,李海,刘颖.一种新的多通道SAR地面动目标检测定位方法.系统工程与电子技术. 2008,30,(5):819~823
43周争光,廖桂生.基于联合特征导向矢量的多通道SAR地面动目标检测定位.西安电子科技大学学报. 2008, 35(5): 585~863
44常玉林,黄晓涛,周红,周智敏.多通道SAR图像域STAP方法.遥感学报. 2009: 238~245
45蔚婧,廖桂生,曾操.基于协方差矩阵特征分解的多通道SAR-GMTI方法及性能分析.电子与信息学报. 2009, 31,(2): 374~377
46李真芳,保铮.基于图像的分布式星载InSAR地面动目标检测方法.分布式小卫星雷达地面动目标指示会论文集. 2005: 72~78