Abstract:Benefiting from the combined processing of echo signals received on spatially separated platforms, bistatic spaceborne SAR has many valuable applications such as survey, interferometry, target recognition and classification, disaster monitoring, etc. In order to improve the imaging performance further, this paper presents a bistatic spaceborne Multiple-Input Multiple-Output SAR (MIMO SAR) system combined with Space-Time Coding (STC) and Short-Term Shift-Orthogonal (STSO) chirp waveforms. With the help of digital beamforming techniques on receive, different transmitting waveforms can be separated and extracted from mixed echoes, so that such enhanced architecture can achieve the advantages of both bistatic and MIMO configuration from more spatial degrees of freedom. Furthermore, it offers an opportunity for mitigating the influences of double-bounce scattering by using beamforming on multiple SAR images. The theoretical analysis is derived in detail, then validated by simulation experiments.
叶恺,禹卫东,王伟. 一种双基星载MIMO SAR系统体制与处理方法[J]. 电子与信息学报, 2017, 39(11): 2697-2704.
YE Kai, YU Weidong, WANG Wei. Investigation on System Scheme and Processing Approach for Bistatic Spaceborne MIMO SAR. JEIT, 2017, 39(11): 2697-2704.
MARC R, PRATS P, SCHULZE D, et al. First bistatic spaceborne SAR experiments with TanDEM-X[J]. IEEE Geoscience and Remote Sensing Letters, 2012, 9(1): 33-37. doi: 10.1109/LGRS.2011.2158984.
[2]
ZINK M, BACHMANN M, BRAUTIGAM B, et al. TanDEM-X: The new global DEM takes shape[J]. IEEE Geoscience and Remote Sensing Magazine, 2014, 2(2): 8-23. doi: 10.1109/MGRS.2014.2318895.
[3]
BUESO J, PRATS P, MARTONE M, et al. Performance evaluation of the TanDEM-X quad polarization acquisitions in the science phase[C]. Preceedings of EUSAR 2016, Hamburg, Germany, 2016: 627-632.
[4]
MOREIRA A, KRIEGER G, HAJNSEK I, et al. Tandem-L: A highly innovative bistatic SAR mission for global observation of dynamic processes on the earth's surface[J]. IEEE Geoscience and Remote Sensing Magazine, 2015, 3(2): 8-23. doi: 10.1109/MGRS.2015.2437353.
[5]
HUBER S, VILLANO M, YOUNIS M, et al. Tandem-L: Design concepts for a next-generation spaceborne SAR system[C]. Preceedings of EUSAR 2016, Hamburg, Germany, 2016: 1237-1241.
[6]
WANG Wenqin. MIMO SAR imaging: potential and challenges[J]. IEEE Aerospace and Electronic Systems Magazine, 2013, 28(8): 18-23. doi: 10.1109/MAES.2013. 6575407.
[7]
KIM J, YOUNIS M, MOREIRA A, et al. Spaceborne MIMO synthetic aperture radar for multimodal operation[J]. IEEE Transactions on Geoscience and Remote Sensing, 2015, 53(5): 2453-2466. doi: 10.1109/TGRS.2014.2360148.
[8]
KRIEGER G, ROMMEL T, and MOREIRA A. MIMO-SAR tomography[C]. Preceedings of EUSAR 2016, Hamburg, Germany, 2016: 91-96.
[9]
WANG Wenqin. MIMO SAR OFDM chirp waveform diversity design with random matrix modulation[J]. IEEE Transactions on Geoscience and Remote Sensing, 2015, 53(3): 1615-1625. doi: 10.1109/TGRS.2014.2346478.
[10]
KRIEGER G, HUBER S, VILLANO M, et al. SIMO and MIMO system architectures and modes for high-resolution ultra-wide-swath SAR imaging[C]. Preceedings of EUSAR 2016, Hamburg, Germany, 2016: 187-192.
[11]
MENG Cangzhen, XU Jia, XIA Xianggen, et al. MIMO-SAR waveform separation based on inter-pulse phase modulation and range-doppler decouple filtering[J]. Electronics Letters, 2013, 49(6): 420-422. doi: 10.1049/el.2013.0016.
[12]
KRIEGER G, GEBERT N, and MOREIRA A. Multidimensional waveform encoding: A new digital beamforming technique for synthetic aperture radar remote sensing[J]. IEEE Transactions on Geoscience and Remote Sensing, 2008, 46(1): 31-46. doi: 10.1109/TGRS.2007.905974.
[13]
KRIEGER G. MIMO-SAR: Opportunities and pitfalls[J]. IEEE Transactions on Geoscience and Remote Sensing, 2014, 52(5): 2628-2645. doi: 10.1109/TGRS.2013.2263934.
[14]
KIM J, YOUNIS M, MOREIRA A, et al. A novel OFDM chirp waveform scheme for use of multiple transmitters in SAR[J]. IEEE Geoscience and Remote Sensing Letters, 2013, 10(3): 568-572. doi: 10.1109/LGRS.2012.2213577.
[15]
WANG Jie, CHEN Longyong, LIANG Xingdong, et al. Implementation of the OFDM chirp waveform on MIMO SAR systems[J]. IEEE Transactions on Geoscience and Remote Sensing, 2015, 53(9): 5218-5228. doi: 10.1109/TGRS. 2015.2419271.
[16]
WANG Wenqin. Space-time coding MIMO-OFDM SAR for high-resolution imaging[J]. IEEE Transactions on Geoscience and Remote Sensing, 2011, 49(8): 3094-3104. doi: 10.1109/ TGRS.2011.2116030.
[17]
WANG Jie, LIANG Xingdong, CHEN Longyong, et al. A novel space-time coding scheme used for MIMO-SAR systems [J]. IEEE Geoscience and Remote Sensing Letters, 2015, 12(7): 1556-1560. doi: 10.1109/LGRS.2015.2412961.
[18]
FENG Fan, LI Shiqiang, YU Weidong, et al. Echo separation in multi- dimensional waveform encoding SAR remote sensing using an advanced null-steering beam-former[J]. IEEE Transactions on Geoscience and Remote Sensing, 2012, 50(10): 4157-4172. doi: 10.1109/TGRS.2012.2187905.
[19]
VAN TREES H. L. Optimum Array Processing Part IV of Detection, Estimation, and Modulation Theory[M]. New York: John Wiley & Sons, 2002: 90-204.
[20]
KRIEGER G, GEBERT N, and MOREIRA A. Unambiguous SAR signal reconstruction from nonuniform displaced phase center sampling[J]. IEEE Geoscience and Remote Sensing Letters, 2004, 1(4): 260-264. doi: 10.1109/LGRS.2004. 832700.