基于导航卫星的干涉SAR数据采集策略优选方法分析

Optimization Method and Analysis of Data Acquisition Strategy Based on Interference SAR with GNSS Transmitters

基于导航卫星的干涉SAR(GNSS-InSAR)使用在轨导航卫星作为照射源,近地面部署接收机,利用导航卫星的星座特性以及重轨特性,可实现区域性的连续观测。对于场景1维/3维形变反演而言,需要连续时间的数据采集,由于导航卫星并非严格意义上的重轨,且重轨时间具有不确定性,原始数据冗余度高,数据对齐时截取量大,数据有效性低。该文针对GNSS-InSAR场景数据采集时间精确性问题,提出了一种重轨数据采集优化模型,该方法通过实际轨迹与TLE预测轨迹相结合的方式,通过空间相干系数的滑窗轨迹对齐,以获取相邻天导航卫星重轨时间间隔,实现精确的GNSS-InSAR数据采集,在降低原始数据冗余度下,保证数据的有效合成孔径时间。实测数据表明所提方法的有效性。

Interference Synthetic Aperture Radar based on the Global Navigation Satellite System(GNSSInSAR) uses in-orbit navigation satellites as transmitters of opportunity and receivers are deployed near the ground. Continuous regional observation can be achieved by the constellation and repeat-pass characteristics of the navigation satellites. Continuous-time data collection is required for 1 D/3 D deformation retrieval of the scene, just like city, bridge, and slope. Since the navigation satellites are not strictly repeat pass and time of repeat pass is uncertain, the original data redundancy is high and interception amount is large when data are aligned, reducing the effect of data. This study focuses on the time accuracy of data acquisition in deformation retrieval of GNSS-InSAR and proposes a repeat-pass data acquisition optimization model, which combines the actual trajectory with the STK, two-line element set prediction trajectory, and sliding window trajectory of the spatial coherence coefficient. Data are aligned to determine the time interval of the adjacent navigation satellites, enabling accurate GNSS-InSAR data acquisition and ensuring effective data accumulation time under reduced original data redundancy. The measured data show the effectiveness of the proposed method.