Articles | Volume 15
Adv. Radio Sci., 15, 231–241, 2017
https://doi.org/10.5194/ars-15-231-2017
Adv. Radio Sci., 15, 231–241, 2017
https://doi.org/10.5194/ars-15-231-2017

  21 Sep 2017

21 Sep 2017

Large-baseline InSAR for precise topographic mapping: a framework for TanDEM-X large-baseline data

Muriel Pinheiro, Andreas Reigber, and Alberto Moreira Muriel Pinheiro et al.
  • German Aerospace Center (DLR), Microwaves and Radar Institute, Oberpfaffenhofen, 82234 Wessling, Germany

Abstract. The global Digital Elevation Model (DEM) resulting from the TanDEM-X mission provides information about the world topography with outstanding precision. In fact, performance analysis carried out with the already available data have shown that the global product is well within the requirements of 10 m absolute vertical accuracy and 2 m relative vertical accuracy for flat to moderate terrain. The mission's science phase took place from October 2014 to December 2015. During this phase, bistatic acquisitions with across-track separation between the two satellites up to 3.6 km at the equator were commanded. Since the relative vertical accuracy of InSAR derived elevation models is, in principle, inversely proportional to the system baseline, the TanDEM-X science phase opened the doors for the generation of elevation models with improved quality with respect to the standard product. However, the interferometric processing of the large-baseline data is troublesome due to the increased volume decorrelation and very high frequency of the phase variations. Hence, in order to fully profit from the increased baseline, sophisticated algorithms for the interferometric processing, and, in particular, for the phase unwrapping have to be considered. This paper proposes a novel dual-baseline region-growing framework for the phase unwrapping of the large-baseline interferograms. Results from two experiments with data from the TanDEM-X science phase are discussed, corroborating the expected increased level of detail of the large-baseline DEMs.

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Short summary
This paper proposes a dual-baseline framework for the unwrapping of large-baseline interferometric SAR data. The algorithm aims at the efficient retrieval of absolute phase measurements regardless the very high frequency of the phase variations associated with large-baseline data. Hence, it promotes the recovery of digital elevation models with very high vertical accuracy, claim which is corroborated by the results obtained from two experiments using data acquired with the TanDEM-X sensor.