Calibration data are taken in a similar way to the Earth view data samples. Data from both calibration sources are used during ground processing of the Earth view data.
On-Board Calibration Target (OBCT)
This hot target comprises an array of Radio Frequency (RF) absorbent pyramids. It will be at ambient temperature (approx 273K) and scanned once during every reflector rotation. During each scan four data samples are taken.
Space View Target
A cold reference data set is generated by sampling data when viewing deep space (approx 4K). As for the OBCT, four data samples are taken during each scan.