Abstract：In bistatic spaceborne High Resolution Wide Swath SAR (HRWS-SAR) system, the Digital Beam Forming (DBF) technique is employed to achieve the coherent combination of multi-channel signals in the fast time domain, and its performance is affected by the bistatic configuration. For a point target, the relationship between receiver aspect angle and the sum of transmitter distance and receiver distance is approximated by a linear function, and the echo signal model in elevation channel is built. Further, a DBF processing scheme is proposed, which combines the time-variant weighting and Finite Impulse Response (FIR) filtering, and the implementation block diagram is presented. The DBF processing is simulated in several typical bistatic configuration spaceborne HRWS-SAR systems. Simulation results show that the higher DBF performance can be achieved in the spaceborne HRWS-SAR system with rational bistatic configuration.
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.
[2]
BUESO J, PRATS P, MARTONE M, et al. Performance evaluation of the TanDEM-X quad polarization acquisitions in the science phase[C]. 11th European Conference on Synthetic Aperture Radar, Hamburg, Germany, 2016: 627-632.
[3]
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.
[4]
HUBER S, VILLANO M, YOUNIS M, et al. Tandem-L: Design concepts for a next-generation spaceborne SAR System[C]. 11th European Conference on Synthetic Aperture Radar, Hamburg, Germany, 2016: 1237-1241.
[5]
SUESS M, ZUBLER M, and ZAHN R. Performance investigation on high resolution wide swath SAR system[C]. 4th European Conference on Synthetic Aperture Radar, Cologne, Germany, 2002: 49-53.
[6]
BORDONI F, YOUNIS M, MAKHAUL V, et al. Adaptive scan-on-receive based on spatial spectral estimation for high- resolution wide-swath SAR[C]. International Geoscience and Remote Sensing Symposium 2009, Cape Town, South Africa, 2009: 431-435. doi: 10.1109/IGARSS.2009.5416941.
[7]
YOUNIS M, HUBER S, PATYUCHENKO A, et al. Performance comparison of reflector- and planar-antenna based digital beam-forming SAR[J]. International Journal of Antennas and Propagation, 2009, 4(6): 379-386.
FENG Fan, LI Shiqiang, and YU Weidong. An improved scheme of digital beam-forming on elevation for spaceborne SAR[J]. Journal of Electronics & Information Technology, 2011, 33(6): 1465-1470. doi: 10.3724/SP.J.1146.2010.01176.
[9]
FENG Fan, DANG Hongxing, TAN Xiaomin, et al. An improved scheme of digital beam-forming in elevation for spaceborne SAR[C]. IET International Radar Conference 2013, Xi,an, China, 2013: 1-6. doi: 10.1049/cp.2013.0208.
[10]
WANG Wei, WANG Robert, DENG Yunkai, et al. An improved processing scheme of digital beam-forming in elevation for reducing resource occupation[J]. IEEE Geoscience and Remote Sensing Letters, 2016, 13(3): 309-313. doi: 10.1109/LGRS.2015.2508098.
[11]
VARONA E M. Adaptive digital beam-forming for high- resolution wide-swath SAR system[D]. [Master dissertation], Universitat Politecnica.de Catalunya, France, 2009.
[12]
WANG Wei, WANG Robert, DENG Yunkai, et al. Improved digital beam-forming approach with scaling function for range multi-channel synthetic aperture radar system[J]. IET Radar, Sonar & Navigation, 2016, 10(2): 379-385. doi: 10.1049/iet-rsn.2015. 0276.
[13]
HUBER S, YOUNIS M, PATYUCHENKO A, et al. A novel digital beam-forming concept for spaceborne reflector SAR system[C]. 6th European Radar Conference, Rome, Italy, 2009: 238-241.
[14]
HUBER S, YOUNIS M, PATYUCHENKO A, et al. Digital beam-forming technqiues for spaceborne reflector SAR systems[C]. 8th European Conference on Synthetic Aperture Radar, Aachen, Germany, 2010: 962-965.
WANG Wei, WANG Yu, and HOU Lili. Analysis on performance of SAR system affected by digital beam forming in elevation[J]. Journal of Electronics & Information Technology, 2014, 36(11): 2711-2716. doi: 10.3724/SP.J.1146. 2013.02002.
LI Yang, HUANG Jiewen, and YU Weidong. Range DBF processing for high-resolution wide-swath spaceborne SAR [J]. Journal of Electronics & Information Technology, 2011, 33(6): 1510-1514. doi: 10.3724/SP.J.1146.2010.01157.
[17]
SUESS M and WIESBECK W. Side-looking synthetic aperture radar system[P]. Euro, Patent EP1241487 A1, 2001.
[18]
LIN Z and LIU Y. Design of arbitrary complex coefficient WLS FIR filters with group delay constraints[J]. IEEE Transactions on Signal Processing, 2009, 57(8): 3274-3279. doi: 10.1109/TSP.2009.2020372 .
ZHOU Qingsong, ZHANG Jianyun, and LI Xiaobo. Optimal design of digital filter with group delay and L1 norm constraints using sequential cone programming[J]. Journal of Circuits and Systems, 2011, 16(1): 52-57.
