Achieving the Evinsar Objectives with Terrasar-l

An L-band InSAR mission, EVINSAR, was proposed to ESA’s Earth Explorer Opportunity Mission programme in 2002 that would measure the strain cycles associated with earthquakes/tectonism and volcanoes. Although not funded the concept was encouraged by ESA and the EVINSAR Science Team was asked to study how the science requirements of EVINSAR could be met by the proposed TerraSAR-L mission. The EVINSAR concept emphasises the collection of a frequent time series of repeat-pass SCANSAR interferograms of the world’s areas of active tectonism and volcanism from an inclined orbital plane and a narrow orbital tube. Leftand right-viewing would alternate with each repeat cycle. These characteristics would obviate baseline decorrelation, minimise topographic noise and maximise the ability to recover the 3D motion vector. L-band radar is needed to reduce temporal decorrelation over vegetation and give the mission a global capability. We have studied TerraSAR-L’s Phase 0 specifications in relation to distributed scatterer differential InSAR. TerraSAR-L goes a considerable way to meeting the EVINSAR science needs. Under ideal conditions it could approach a target minimum strain rate sensitivity of 1mm/10km/year. However, the polar orbit of TerraSAR-L and only limited capability for left-sided viewing reduces the ability to retrieve the 3D motion vector from multiple views.