A global ERS-1/2 SAR wave mode imagettes calibration method

• Published in: Seventh International Conference on Electronic Engineering in Oceanography - Technology Transfer from Research to Industry pp. 233 - 237
• Main Authors: Kerbaol, V, Chapron, B, Garello, R
• Format: Conference Proceeding
• Language: English
• Published: London IEE 1997
• Subjects: Instrumentation and techniques for geophysical, hydrospheric and lower atmosphere research; Measurement standards and calibration; Oceanographic and hydrological techniques and equipment; Radar equipment, systems and applications; Surface waves, tides, and sea level; oceanographic techniques; ERS-1 SAR data; ERS-2 data; incidence angle; synthetic aperture radar; global wave mode imagettes calibration method; SAR imagette radiometric precision analysis; analogue-digital converter saturation; calibration constant retrieval; remote sensing by radar; scatterometer central antenna measurements; calibration; ocean waves; scattering model CMOD IFREMER
• ISBN: 085296689X; 9780852966891
• DOI: 10.1049/cp:19970690

In absence of specific information for SAR imagette radiometric precision analysis, the authors' method is to derive a relative calibration from global direct comparisons between co-located SAR and scatterometer central antenna measurements. Such a method led the authors to refine the exact incidence angle used to obtain the ERS-1/2 SAR wave mode products. The study clearly shows the evidence of the change of imagettes incidence angle on ERS-1 data. Moreover, it is shown that ERS-2 data are almost not affected by the analog-digital converter saturation because of a reduction in on-board gains. The issue of the calibration constant K retrieval is addressed and K values are given for both configurations of ERS-1 SAR and for ERS-2. Finally, the consistency of this empirical calibration method is discussed in comparison with scattering model CMOD IFREMER.