Abstract：For conventional quadrature-polarimetric (quad-pol) Synthetic Aperture Radar (SAR) systems, as cross-polarized (cross-pol) channels are influenced by the strong co-polarized (co-pol) range ambiguous returns, the range ambiguity levels of cross-polchannels are markedly reduced, which severely restricts the unambiguous swaths. A novel transmission scheme called a hybrid-polarimetric (hybrid-pol) mode is introduced to enhance the range ambiguity levels of cross-pol channels. This scheme improves the performance of cross-pol channels with regards to range ambiguity but deteriorates that of co-pol channels. Therefore, to further enhance the range ambiguity levels of quad-pol SAR systems, the Modified Azimuth Phase Coding (MAPC) technique based on hybrid-pol SAR systems is proposed in this study. By taking advantage of the MAPC modulation/demodulation, the power of range ambiguities is transferred to the azimuth that is filtered by an optimized Wiener filter in the Doppler domain. The simulation results validate that the MAPC technique can markedly eliminate the range ambiguity of quad-pol SAR systems and extend the unambiguous swaths.
祝晓静, 李 飞, 王 宇, 王 伟, 孙 翔. 基于改进方位相位编码的全极化SAR距离模糊抑制方法[J]. 雷达学报, 2017, 6(4): 420-431.
Zhu Xiaojing, Li Fei, Wang Robert, Wang Wei, Sun Xiang. Range Ambiguity Suppression Approach for Quad-pol SAR Systems Based on Modified Azimuth Phase Coding. JOURNAL OF RADARS, 2017, 6(4): 420-431.
Raney R K, Freeman A, and Jordan R L. Improved range ambiguity performance in quad-pol SAR[J]. IEEE Transactions on Geoscience and Remote Sensing, 2012, 50(2): 349-356. DOI:10.1109/TGRS.2011.2121075
Yang Ru-liang, Dai Bo-wei, and Li Hai-ying. Polarization hierarchy and system operating architecture for polarimetric synthetic aperture radar[J]. Journal of Radars, 2016, 5(2): 132-142.
[3]
Mittermayer J and Martínez J M. Analysis of range ambiguity suppression in SAR by up and down chirp modulation for point and distributed targets[C]. Proceedings of the 2003 IEEE International Geoscience and Remote Sensing Symposium, Toulouse, France, 2003, 6: 4077-4079.
[4]
Dall J and Kusk A. Azimuth phase coding for range ambiguity suppression in SAR[C]. Proceedings of the 2004 IEEE International Geoscience and Remote Sensing Symposium, Anchorage, AK, USA, 2004, 3: 1734-1737.
[5]
Bordoni F, Younis M, and Krieger G. Ambiguity suppression by azimuth phase coding in multichannel SAR systems[J]. IEEE Transactions on Geoscience and Remote Sensing, 2012, 50(2): 617-629. DOI:10.1109/TGRS.2011.2161672
[6]
Yang Jun, Sun Guang-cai, Wu Yu-feng, et al.. Range ambiguity suppression by azimuth phase coding in multichannel SAR systems[C]. Proceedings of IET International Radar Conference 2013, Xi'an, China, 2013: 1-5.
[7]
Gebert N, Krieger G, and Moreira A. Digital beamforming on receive: Techniques and optimization strategies for high-resolution wide-swath SAR imaging[J]. IEEE Transactions on Aerospace and Electronic Systems, 2009, 45(2): 564-592. DOI:10.1109/TAES.2009.5089542
[8]
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
[9]
Huber S, Younis M, Patyuchenko A, et al.. Digital beam forming techniques for spaceborne reflector SAR systems[C]. Proceedings of the 2010 8th European Conference on Synthetic Aperture Radar (EUSAR), Aachen, Germany, 2010: 1-4.
[10]
Di Martino G, Iodice A, Riccio D, et al.. Filtering of azimuth ambiguity in stripmap synthetic aperture radar images[J]. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2014, 7(9): 3967-3978. DOI:10.1109/JSTARS.2014.2320155
[11]
Guarnieri A M. Adaptive removal of azimuth ambiguities in SAR images[J]. IEEE Transactions on Geoscience and Remote Sensing, 2005, 43(3): 625-633. DOI:10.1109/TGRS.2004.842476
Hong Wen, Yang Shi-lin, Li Yang, et al.. Study on polarimetric SAR range ambiguity computation for distributed targets[J]. Journal of Electronics & Information Technology, 2015, 37(6): 1437-1442. DOI:10.11999/JEIT141234
[13]
Li P K and Johnson W T K. Ambiguities in spaceborne synthetic aperture radar systems[J]. IEEE Transactions on Aerospace and Electronic Systems, 1983, AES-19(3): 389-397. DOI:10.1109/TAES.1983.309319
[14]
Callaghan G D and Longstaff I D. Wide-swath space-borne SAR and range ambiguity[C]. Proceedings of Radar 97 (Conf. Publ. No. 449), Edinburgh, UK, 1997: 248-252.
[15]
Cordey R. Range ambiguities for a polarimetric spaceborne SAR[C]. Proceedings of IEEE International Geoscience and Remote Sensing Symposium, Houston, TX, USA, 1992: 637-639.
[16]
Raney R K. Hybrid-polarity SAR architecture[J]. IEEE Transactions on Geoscience and Remote Sensing, 2007, 45(11): 3397-3404. DOI:10.1109/TGRS.2007.895883
[17]
Raney R K, Spudis P D, Bussey B, et al.. The lunar mini-RF radars: Hybrid polarimetric architecture and initial results[J]. Proceedings of the IEEE, 2011, 99(5): 808-823. DOI:10.1109/JPROC.2010.2084970
[18]
Raney R K. A ‘free’ 3-dB cross-polarized SAR data[J]. IEEE Transactions on Geoscience and Remote Sensing, 1988, 26(5): 700-702. DOI:10.1109/36.7698
Guo Lei, Wang Yu, Deng Yun-kai, et al.. Range ambiguity suppression for multi-channel SAR system using azimuth phase coding technique[J]. Journal of Electronics & Information Technology, 2015, 37(3): 601-606. DOI:10.11999/JEIT140707
2017, Vol. 6 
