一种基于天线指向的大方位扫描滑聚模式星载SAR几何定位技术

doi:10.12305/j.issn.1001-506X.2026.03.12

摘要/Abstract

摘要：

由于滑聚模式成像算法中的去斜操作，难以构建一个严密的距离-多普勒方程用于几何处理。对此，提出基于合成孔径雷达（synthetic aperture radar，SAR）天线指向矢量的构像模型，充分考虑滑聚成像的去斜操作对斜距影像产生的影响。从SAR图像每个扫描行的像点与卫星的相对位置出发，基于准确的星地几何条件，建立图像像点坐标与地理坐标的严格转换模型，并以此模型给出了滑聚模式SAR几何定位的正解和反解流程。最后，利用不同脉宽带宽组合、不同外场数据开展的几何定标和定位处理实验表明，在标校补偿了SAR载荷自身以及大气传输、平台轨道位置、高程等因素带来的各项几何误差后，滑聚影像的无控几何定位精度能达到1~2 m，充分证明了所提方法在滑聚影像几何定位方面的有效性。

关键词: 合成孔径雷达, 滑聚成像, 去斜, 距离-多普勒, 几何定位

Abstract:

Because of the dechirp operation in the imaging algorithm of the sliding-spot mode, it is difficult to construct a rigorous range-Doppler equation for its geometric processing. In regard to this, a conformation model based on synthetic aperture radar （SAR） antenna pointing vector is presented, which fully considering the influence of the dechirp operation on the sliding-spot imaging. Starting from the relative position between the image points of each scanning line in SAR images and the satellite, based on accurate satellite-to-ground geometric conditions, a strict transformation model between image point coordinates and geographic coordinates is established. Based on this model, the forward and inverse solution processes for SAR geometric positioning in sliding mode are given. Finally, geometric calibration and positioning processing experiments using different pulse width combinations and different field data showed that after compensating for various geometric errors caused by the SAR payload itself, atmospheric transmission, platform orbit position, elevation, and other factors, the uncontrolled geometric positioning accuracy of the sliding-spot image can reach 1?2 m, fully demonstrating the effectiveness of the proposed method in the geometric positioning of sliding-spot images.

Key words: synthetic aperture radar (SAR), sliding-spot imaging, dechirp, range-Doppler (RD), geometric positioning

中图分类号:

TN 958

李莹莹, 吴昊, 陈凤, 林郁卓越, 王雪莹, 冯鑫. 一种基于天线指向的大方位扫描滑聚模式星载SAR几何定位技术[J]. 系统工程与电子技术, 2026, 48(3): 846-858.

Yingying LI, Hao WU, Feng CHEN, Yuzhuoyue LIN, Xueying WANG, Xin FENG. A geometric positioning technology based on antenna pointing for large azimuth scanning sliding-spot mode of spaceborne SAR[J]. Systems Engineering and Electronics, 2026, 48(3): 846-858.

图/表 23

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参数	取值
卫星轨道高度/km	600
方位向斜视扫描角范围/（°）	13.13~ 4.93
距离向中心视角/（°）	27
信号带宽/MHz	800
信号采样率/MHz	1 000
卫星平台速度/（km/s）	7.62
PRF/Hz	5 182
成像时长/s	15.26
距离向采样点数	25 600
方位向采样点数	46 272

带脉组合	定标影像ID及获取时间	侧视角/（°）	轨道	侧视
B1	Image 1（2021/5/12）	50.27	升轨	右
	Image 2（2021/4/22）	47.93	降轨	左
	Image 3（2021/5/21）	47.43	降轨	左
B2	Image 4（2021/4/21）	28.44	降轨	左
B3	Image 5（2021/4/13）	54.92	降轨	左
	Image 6（2021/5/17）	52.11	升轨	右
	Image 7（2021/5/7）	53.21	降轨	左
	Image 8（2021/12/2）	53.21	升轨	左
	Image 9（2021/4/19）	44.96	升轨	左
	Image 10（2021/4/13）	50.7	升轨	右
	Image 11（2021/4/14）	58.86	升轨	右
B4	Image 12（2021/4/29）	39.37	升轨	左
B5	Image 13（2021/5/1）	23.62	升轨	右
	Image 14（2021/5/9）	18.33	降轨	右
	Image 15（2021/12/15）	31.39	升轨	右
	Image 16（2021/12/18）	29.44	升轨	左
	Image 17（2021/5/19）	23.62	升轨	左
B6	Image 18（2021/4/23）	57.2	降轨	左

带脉组合	验证影像ID及获取时间	侧视角/（°）	轨道	侧视
B1	Image 1（2021/08/23）	48.43	降轨	左
	Image 2（2021/08/22）	48.18	降轨	右
	Image 3（2021/07/20）	51.72	升轨	左
B2	Image 4（2021/07/02）	28.94	升轨	左
	Image 5（2021/06/19）	28.94	降轨	右
	Image 6（2021/06/19）	21.32	升轨	右
B3	Image 7（2021/08/23）	50.7	升轨	左
B3	Image 8（2021/06/30）	49.14	升轨	左
B4	Image 9（2021/08/24）	34.99	升轨	左
	Image 10（2021/06/17）	34.56	降轨	右
	Image 11（2021/06/12）	42.16	升轨	左
B5	Image 12（2021/08/21）	29.94	降轨	左
	Image 13（2021/07/23）	25.27	升轨	左
	Image 14（2021/06/09）	19.54	降轨	右

时宽带宽组合	参与定标的影像数量	Incalib 1 （未剔异常值）		Incalib 2 （剔除异常值）
时宽带宽组合	参与定标的影像数量	斜距改正值中误差/ m	方位向时间改正值中误差/ ms	斜距改正值中误差/m	方位向时间改正值中误差/ ms
B1	3	12.046	3.333	13.035	1.126
B3	7	12.367	3.708	12.93	2.160
B5	5	9.946	2.661	10.662	1.809

误差补偿	距离向	方位向
全部误差均补偿	0.396±0.78	−0.63±1.31
无大气延迟校正	5.61±0.78	−0.63±1.31
未用精确高程校正	11.69±5.41	−0.89±1.55
未用精密轨道校正	2.06±0.82	−1.85±1.35
未进行时延校正	13.43±0.78	−0.63±1.31
全部误差均未补偿	31.61±5.46	−2.11±1.59