Method to estimate the Doppler parameters of moon-borne SAR using JPL ephemeris
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摘要: 月基合成孔径雷达(SAR)与传统低轨SAR相比,成像几何上存在成像距离长的特点,其多普勒参数估计方法也不同于常规的机载和星载SAR.基于喷气推进实验室(JPL)高精度星历,可以通过插值获取月心在地心惯性坐标系下的位置、速度和加速度以及月球天平动,然后经由坐标转换得到月面任意位置在地心惯性坐标系下的位置、速度和加速度.在此基础上,建立了两个二次方程组,第1个方程组的解表示任意星下点离线角和斜视角情况下的波束矢量,第2个方程组求得波束矢量的模值,以此解算地面波束中心的坐标.结果表明,月基SAR的波束角需沿轨不断调整,而且天线放置的位置也会对多普勒参数产生明显影响.Abstract: Compared with the low earth orbit synthetic aperture radar (SAR) system, the moon-borne SAR is distinct from its unique imaging geometry, so the Doppler parameters estimation method is different from conventional pickaback and satellite-borne SAR. Precise jet propulsion laboratory (JPL) ephemeris was used to interpolate the position, velocity and acceleration of lunar barycenter as well as the libration in geocentric inertial coordinate system. Then the position, velocity and acceleration of an object at any selenographic coordinates were able to be acquired via the coordinate transformation. Based on this, two quadratic equation sets were put forward to calculate the beam direction at any off-nadir angle and squint angle, and to solve the modulus value of line of sight, then coordinating the footprint center. Simulation results show that the beam angle needs a continuous adjustment along the orbit to point the earth disk in moon-borne SAR case, and the antenna position displacement leads to a significant shift on the Doppler parameters.
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[1] Kiyo T,Jean P.Synthetic aperture radar imaging from an inclined geosynchronous orbit[J].IEEE T Geosci Remote Sens,1983,GE-21(3):324-329. [2] Prati C,Rocca F,Giancola D,et al.Passive geosynchronous SAR system reusing backscattered digital audio broadcasting signals[J].IEEE T Geosci Remote Sens,1998,36(6):1973-1976. [3] Bruno D,Hobbs S,Ottavianelli G.Geosynchronous synthetic aperture radar:concept design,properties and possible applications[J].Acta Astronaut,2006,59(1):149-156. [4] Fornaro G,Franceschetti G,Lombardini F,et al.Potentials and limitations of moon-borne SAR imaging[J].IEEE T Geosci Remote Sens,2010,48(7):3009-3019. [5] Guo H D,Ding Y X,Liu G,et al.Conceptual study of lunar-based SAR for global change monitoring[J].Science China:Earth Sciences,2014,57(8):1771-1779. [6] Moccia A,Renga A.Synthetic aperture radar for Earth observation from a lunar base:performance and potential applications[J].IEEE T Aero Elec Sys,2010,46(3):1034-1051. [7] Raney R K.Doppler properties of radars in circular orbits[J].International Journal of Remote Sensing Letters,1986,7(9):1153-1162. [8] Curlander J C,Mcdonough R N.Synthetic aperture radar system and signal processing[M].New York:Wiley,1991. [9] Cumming I G,Wong F H.Digital processing of synthetic,aperture radar data:algorithms and implementation[M].Boston:Artech House,2005. [10] 杨文付,曾涛,丁泽刚.基于星历数据的SAR多普勒参数计算[J].北京理工大学学报,2010,30(10):1221-1225.Yang W F,Zeng T,Ding Z G.Doppler parameters calculation of SAR based on satellite ephemeris[J].Transactions of Beijing Institute of Technology,2010,30(10):1221-1225(in Chinese). [11] 文竹,周荫清,陈杰.高精度星载SAR多普勒参数估算方法[J].北京航空航天大学学报,2006,32(12):1418-1421.Wen Z,Zhou Y Q,Chen J.Accurate method to calculate space-borne SAR Doppler parameters[J].Journal of Beijing University of Aeronautics and Astronautics,2006,32(12):1418-1421(in Chinese). [12] 郑经波,宋红军,尚秀芹,等.地球同步轨道星载SAR多普勒特性分析[J].电子与信息学报,2011,33(4):810-815.Zheng J B,Song H J,Shang X Q,et al.Doppler properties analysis of GEO spaceborne SAR[J].Journal of Electronics & Information Technology,2011,33(4):810-815(in Chinese). [13] 赵秉吉,齐向阳,宋红军,等.基于椭圆轨道的Geo-SAR精确多普勒参数解析计算方法[J].电子与信息学报,2012,34(11):2642-2647.Zhao B J,Qi X Y,Song H J,et al.Accurate Doppler parameters estimation of Geo-SAR based on elliptical orbit[J].Journal of Electronics & Information Technology,2012,34(11):2642-2647(in Chinese). [14] Murphy T W.Lunar laser ranging:the millimeter challenge[J].Reports on Progress in Physics,2013,76(7):076901. [15] Standish E M.JPL planetary and lunar ephemerides,DE 405/LE 405[EB/OL],California:Jet Propulsion Laboratory,1998(1998-08-26)[2014-01-05].
[IOM 312.F 98 048],http://iau-comm4.jpl.nasa.gov/de405iom/de405iom.pdf.[16] 郗晓宁,曾国强,任萱,等.月球探测器轨道设计[M].北京:国防工业出版社,2001.Xi X N,Zeng G Q,Ren X.Orbit design of lunar probe[M].Beijing:National Defense Industry Press,2001(in Chinese)
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