Coregistration of Sentinel-1 TOPS Data for Interferometric Processing Using Real-Time Orbit

An azimuth coregistration accuracy of 0.001 pixel is required for Sentinel-1 terrain observation by progressive scans (TOPS) interferometric processing, which is usually accomplished by a geometric coregestration and enhanced spectral diversity based on precise orbit information. However, the precise orbit information is distributed later than TOPS synthetic aperture radar (SAR) products, and the accuracy of real-time orbits is not high enough, which could result the phase of enhanced spectral diversity wrapped after geometric coregistration. We aim to improve the geometric coregistration accuracy using real-time orbits to meet the requirement of interferometric processing of Sentinel-1. Firstly, the windows centered by point scatterers are selected to perform the cross correlation coregistration. Then, multi-bursts results are mosaicked to improve the accuracy and reliability of cross correlation coregistration approach, which promises the coregistration accuracy for enhanced spectral diversity. Finally, this method is validated by a real case.