ESA Earth Home Missions Data Products Resources Applications
EO Data Access
How to Apply
How to Access
FRINGE '96 Workshop: ERS SAR Interferometry, 30 September - 2 October 1996
Site Map
Frequently asked questions
Terms of use
Contact us


Fringe 96

Initial testing of ERS Tandem data quality for InSAR applications

Examples from Taiwan, Madagascar, Zaire, Ivory Coast, Mali and Greenland

Gaute Aa Solaas ESA/ESRIN/ RS/E Data Utilisation Section

Fabio Gatelli Politecnico di Milano, Dipartimanto di Elettronica e Informazione, Under contract to ESA/ESRIN RS/P ERS Section


A preliminary investigation has been performed in which interferometric products were generated from selected ERS tandem data. The data covered a number of areas throughout the world and represented a variety of land cover types ranging from glaciers to tropical forests, savannah and deserts. A prototype interferometric quick-look processor was used in an ad-hoc operation where relatively large amounts of data were processed in a short time period (over 50 standard frames of ERS data). In addition to demonstrating the potential of quick-look InSAR processing we could draw the following preliminary conclusions:

  • Tandem InSAR coherence over dense rain-forest is low and results in highly fragmented fringe-areas. This can be exploited in several applications concerned with land use monitoring.
  • Over mountain rainforest the fragmentation is even more pronounced due to the effect of foreshortening and layover on SAR imagery. This can partly be remedied by combining interferogrammes from ascending and descending passes, but remains a serious obstacle for operational use of ERS InSAR over mountainous terrain.
  • Maximum NDVI, as derived from AVHRR over a two month period (to eliminate cloud and haze signatures), can be an important tool for establishing the expectancy of high coherence areas. This can help the user in identifying the areas where a specific application has highest probability of success and can be a major cost saver if e.g. large scale use of ERS InSAR in mapping is going to be carried out.
  • Tandem InSAR has high potential in arctic and Antarctic areas due to the high coherence obtained over dry snow and ice and sparse vegetation. Since there are large amounts of data acquired over these areas the user applications should be assured in most instances.

The results presented here are available from ESRIN under the reference: RS/ED96.D002


Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry