National Laboratory of Radar Signal Processing, Xidian University, Xi'an 710071, China.
Institute of Space-Terrestrial Intelligent Networks (ISTIN) Group, Nanjing University, Nanjing 210023, China.
Sensors (Basel). 2018 Jul 4;18(7):2152. doi: 10.3390/s18072152.
For Interferometry Synthetic Aperture Radar (InSAR), the normal baseline is one of the main factors that affects the accuracy of the ground elevation. For Gaofen-3 (GF-3) InSAR processing, the poor accuracy of the real-time orbit determination results in a large baseline error, leads to a modulation error in azimuth and a slope error in the range for timely Digital Elevation Model (DEM) generation. In order to address this problem, a novel baseline estimation approach based on Shuttle Radar Topography Mission (SRTM) DEM is proposed in this paper. Firstly, the orbit fitting is executed to remove the non-linear error factor, which is different from traditional methods. Secondly, the height errors are obtained in a slant-range plane between SRTM DEM and the GF-3 generated DEM, which can be used to estimate the baseline error with a linear variation. Then, the real-time orbit can be calibrated by the baseline error. Finally, the DEM generation is performed by using the modified baseline and orbit. This approach has the merit of spatial and precise orbital free ability. Based on the results of GF-3 interferometric SAR data for Hebei, the effectiveness of the proposed algorithm is verified and the accuracy of GF-3 real-time DEM products can be improved extensively.
对于干涉合成孔径雷达（InSAR），正常基线是影响地面高程精度的主要因素之一。对于高分三号（GF-3）InSAR 处理，实时轨道确定结果精度差会导致基线误差较大，从而导致方位调制误差和范围斜率误差，及时生成数字高程模型（DEM）。为了解决这个问题，本文提出了一种基于航天飞机雷达地形测绘任务（SRTM）DEM 的新基线估计方法。首先，执行轨道拟合以消除与传统方法不同的非线性误差因素。其次，在 SRTM DEM 和 GF-3 生成的 DEM 之间的斜距平面上获得高程误差，可用于估计具有线性变化的基线误差。然后，可以通过基线误差校准实时轨道。最后，通过修改后的基线和轨道生成 DEM。该方法具有空间和精确轨道自由的优点。基于 GF-3 干涉合成孔径雷达数据对河北的结果，验证了所提出算法的有效性，可以广泛提高 GF-3 实时 DEM 产品的精度。
