TanDEM-X Long-Term System Performance After 10 Years of Operation

Abstract

The TanDEM-X mission, formed by the TanDEM-X satellite (TDX) in cooperation with its almost identical twin TerraSAR-X (TSX), has mainly been designed to acquire bistatic Synthetic Aperture Radar (SAR) images of the Earth. Initiated in 2010, the primary mission objectives were to generate a global Digital Elevation Model (DEM), to perform scientific measurements and to explore novel SAR techniques. Up to the present day all these objectives have been completed with outstanding results. In addition, the satellites maintained a stable image quality from the start throughout their entire lifetime. The ground segment, which was tailored to the capabilities of the space segment, as well as an excellent design and manufacturing of the satellites were the key elements to achieve such a performance. In addition, the elaborate calibration concept and a careful treatment of the on-board resources enabled full operability up to the present day and allowed additional mission objectives such as the generation of a Change-DEM layer as an update to the global DEM. The stable bus and SAR payload performance as revealed by long-term system monitoring provide the basis for further extension of the TanDEM-X mission for several more years. In the following paper these long-term system monitoring results are presented to provide an overview of the evolution of the radar system. The results and experience gained with more than a decade of TanDEM-X mission operation are a great value for both the scientific and commercial community and serve as a forerunner for the development of future SAR missions.

TerraSAR-X and TanDEM-X After 13 Years of Joint SAR and DEM Mission

“…After readjustment, calibration verification and reestablishment of the formation, the high quality of the SAR and DEM products was similar as before [8]. Since the beginning of the mission, the relative radiometric performance is thus well within specifications [6].…”

“…The long duration of both missions results in a significant aging of the satellite components. However, both satellites work stable within their performance specifications and are still remarkably well calibrated since the start of the operational phase [5], [6].…”

The utility of TerraSAR-X, TanDEM-X, and PAZ for studying global volcanic activity: Successes, challenges, and future prospects

“…It would also be advantageous to coordinate TSX/TDX/PAZ global volcano acquisition strategies with other SAR constellations through a Volcano Space Task Group [Pritchard et al 2022a] so that each set of satellites collect data in complementary modes (ascending vs. descending, incidence angle, SM vs. SL, etc.). The TSX/TDX mission has already significantly exceeded its designed lifetime (5.5 yr −1 ), even though it is expected to remain operational for a few more years [Buckreuss et al 2018;Bojarski et al 2021]. Future missions that continue the capacity of this successful constellation, especially in terms of acquisition of bistatic data, would benefit for volcanological applications.…”

Joint PAZ & TanDEM-X Mission Interferometric Experiments: Interoperability and Products

“…It is deployed within the DLR satellite ground station premises there and consists of three Corner Reflectors (CR) of 1.5 m length. Regular acquisitions have been planned and executed by both satellites since their respective launch in 2007 and 2010 and their evaluation shows no degradation of the SAR instruments to this day [6], [7]. The CRs are permanently aligned in accordance with two different SAR geometries: strip 11 and strip 6 [8].…”