Abstract
The atmospheric propagation delay of radar signals is a systematic error that occurs in the atmospheric environment, and is a key issue in the high-precision geometric calibration of spaceborne SAR. A multimode hybrid geometric calibration method for spaceborne SAR that considers the atmospheric propagation delay is proposed in this paper. Error sources that affect the accuracy of the geometric calibration were systematically analyzed. Based on correction of the atmospheric propagation delay, a geometric calibration model for spaceborne SAR was established. The high precision geometric calibration scheme for spaceborne SAR was explored by considering the pulse-width and bandwidth of the signal. A series of experiments were carried out based on high-resolution Yaogan 13 (YG-13) SAR satellite data and ground control data. The experimental results demonstrated that the proposed method is effective. The plane positioning accuracy of YG-13 in stripmap mode without control points is better than 3 m, and the accuracy of the sliding spotlight mode is better than 1.5 m.
Highlights
Geometric calibration is a crucial component of satellite in-orbit tests of synthetic aperture radar (SAR) systems
It allows the geometric accuracy of a spaceborne SAR system to reach the theoretical limit, and is the key factor affecting the subsequent application of SAR image data
It can be seen from the comparison that the geometric calibration results of Yaogan 13 (YG-13) without considering the pulse-width and bandwidth combination are worse than those of the proposed method
Summary
Geometric calibration is a crucial component of satellite in-orbit tests of synthetic aperture radar (SAR) systems. It allows the geometric accuracy of a spaceborne SAR system to reach the theoretical limit, and is the key factor affecting the subsequent application of SAR image data. SAR satellites do not consider the influence of atmospheric propagation delay To some extent, this affects the accuracy of the geometric calibration. In this paper, we propose a multimode hybrid geometric calibration method for spaceborne SAR that considers the atmospheric propagation delay. This paper describes the multimode hybrid geometric calibration method of spaceborne SAR considering atmospheric propagation delay.
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