Image quality and calibration of RADARSAT-2

RADARSAT-2 has 177 operational imaging modes. Versions of each of these modes are available either for left-or right-looking imaging, and most modes allow images to be generated for any of the four linear polarization combinations (HH, VV, HV, VH). To support these modes there are currently 1816 sets of beam coefficients and 16 digitized pulse forms stored on the spacecraft. The radar employs a number of SAR techniques besides the established Stripmap and ScanSAR of RADARSAT-1, including alternating transmit polarization, Dual-Receive (separately on the two antenna wings) and Stitched Pulse. All these factors that provide the versatility for the system also increase the complexity of the task to establish and maintain image quality and calibration. This paper covers work that was undertaken to achieve an efficient image quality and calibration campaign during the first four months of the mission, and to maintain and upgrade imaging capabilities and quality since that period.