Ers-2 Sar Performance and Product Evolution

The European Space Agency (ESA) ERS-2 Synthetic Aperture Radar (SAR) has successfully operated for more than 12 years. The performance of the ERS-SAR is routinely assessed via a variety of quality assessment and calibration measures. This paper gives the latest ERS-2 SAR quality assessment and calibration results, including elevation antenna pattern estimation and monitoring, updates to ERS-2 SAR internal calibration and stability, noise equivalent radar cross-section measurements, updates to the ERS-2 nominal replica pulse correction table and image localisation results. Equations are given for the calculation of distributed and point target radar cross-sections from the threelook ground range detected ERS-2.SAR.PRI and the single-look slant range complex ERS-2.SAR.SLC products. Also given are ERS-2 attitude and SAR Doppler variations following the change from three to one gyroscope operations in February 2000 and the change to gyro-less operations in February 2001. Finally a brief description is given of the evolution and harmonisation during 2006 of ERS SAR products from VMP to PGS-ERS processors and to the same specification as Envisat ASAR product.