Reprocessing of the ERS Altimetry Missions- The REAPER Project
Abstract
ESA's first Remote Sensing Satellite: ERS-1, was launched on July 17, 1991 and operated until June 1996, completing one year of parallel operation (Tandem Mission) with ERS-2. Launched in April 1995, ERS-2 operated until July 2011 with all instrumentation still working well despite the loss of the on-board tape recorders and the transition to gyro-less pointing. After the launch of Envisat in March 2002, the continuing operation of ERS-2 provided a valuable overlap of the Radar Altimeter missions.The existing ERS Altimetry data set (OPR and WAP products) is known to be not fully homogenous over the two-mission lifetime, as a result of different algorithmic evolutions performed on the ERS-1 and ERS-2 ground processing chains and of changes in the RA and MWR sensors behaviour due to ageing effects and on-board anomalies.The goal of the Reaper project is to reprocess all available ERS-1 and ERS-2 RA and MWR data, from July 1991 through to June 2003, to produce a coherent and homogeneous long-term series that is cross calibrated and offers continuity with the RA2 mission. The use of the latest models will improve the geophysical corrections applied to the range measurement. By revisiting the instrument calibration algorithms and applying retrospectively the experience gained on the effects of instrument ageing further improvements in measurement accuracy are gained. Derivation of a new Precise Orbit solution across the 12 year period will result in a significant improvement to the orbit accuracy and hence the final surface height measurements.The resulting data set will allow greater exploitation of the full potential of the archived ERS Altimetry data set over ocean, land and ice surfaces, than previously possible. This paper briefly outlines the new processing algorithms and geophysical models that are implemented in the REAPER reprocessing chains, and discusses the improvement in measurement accuracy achieved.
- Publication:
-
20 Years of Progress in Radar Altimatry
- Pub Date:
- September 2013
- Bibcode:
- 2013ESASP.710E..70B