Techniques for high accuracy relative and absolute localization of TerraSAR-X / TanDEM-X data

Abstract

The German SAR (synthetic aperture radar) satellites TSX-1 and TDX-1 outperform former civilian space-borne radar sensors in terms of geometric accuracy. Recently, both satellites constitute the first bistatic SAR system in space: TanDEM -X. With the high geometric accuracy of both satellites, the geolocation of ground targets has to accurately consider signal propagation effects and geodynamic effects which formerly were negligible. The prediction of expected radar positions is additionally complicated by the bistatic acquisition geometry of TanDEM-X. Here, we present our approach to cope with these demanding requirements. With the application of these techniques, measurements of the geometric accuracy of TSX-1 and TDX-1 reveal that their pixel localization accuracy is significantly better than in previous studies.

High resolution geodetic earth observation with TerraSAR-X: Correction schemes and validation

“…The German SAR (Synthetic Aperture Radar) satellites Ter-raSAR-X (TSX-1) and TanDEM-X (TDX-1), launched in June 2007 and June 2010 respectively, provide an unprecedented geometric accuracy. Previous studies showed an absolute pixel localization accuracy for both sensors at the centimeter level [1][2][3][4][5]. However, we expect that by a thorough correction of all path delays and geodynamic effects even an improvement to the sub-centimeter level seems attainable [6].…”

High precision measurement on the absolute localization accuracy of TerraSAR-X

“…In contrast, almost all immediately neighboring measurement values typically differ by millimeters. Thus, on a short-term scale, our recent measurements point to a much better localization accuracy for TerraSAR-X than is known from our previous investigations [4] [6].…”

“…However, a thorough consideration of the varying amount of all geodynamic effects and signal propagation delays significantly decreases the spread of results in a localization measurement series [4]. In this respect, the standard deviation of the effect under consideration determines the relevance of the respective correction.…”

“…With the high geometric accuracy of both satellites, the geolocation of ground targets has to accurately consider signal propagation effects and geodynamic effects such as solid earth tides and the continental drift which were formerly negligible [1] [2] [3]. Previous studies which took these effects carefully into account showed an absolute pixel localization at the centimeter level for TSX-1 and TDX-1 [4] [5] [6]. However, recent measurements show that in range, under extraordinary good conditions, a location accuracy of just a few millimeters seems to be feasible.…”

Error Budget Analysis for Geolocation Accuracy of High Resolution SAR Satellite Imagery

“…최근에는 신호 지연 및 지각 오차 보정을 통해 서 TerraSAR-X가 cm 단위의 위치정확도를 확보 가능함을 Corner reflector를 통해 확인하였다 (Balss et al, 2013). Schubert et al, 2012;Balss et al, 2011;Balss et al, 2013). (Curlander et al, 1991;Frey et al, 2004).…”