Minimize GOMOS Cal/Val
Minimize Calibration Activities

Typical Routine Calibration sequence 

Seven consecutive orbits per month were acquired with the instrument in different monitoring modes.:

  • 1 orbit in SSM mode. The brightest stars have to be chosen (this cannot be done automatically by Starsel). At least 6 stars in dark limb (including at least 3 in eclipse) and 3 stars in bright limb.
     
  • 2 orbits in UNI mode, one at 10 km and one at 30 km altitude. The start times and the durations are always the same. The integration time is 0.5 s except for the last observation of the orbit. The azimuth is always equal to 30°. The location of the SATU windows is always the same.
     
  • 2 orbits in LIN mode, from 300 to 100 km altitude. The brightest stars have to be chosen (this cannot be done automatically by Starsel). At least 6 stars in dark limb (including at least 3 in eclipse) and 3 stars in bright limb. The integration time is 0.25 s for the first orbit and 0.5 s for the second one.
     
  • 2 orbits in OCC with as much Dark Sky Area (DSA) acquisitions as possible. The altitude range is 300 to 200 km for the first orbit and 300 to 0 km for the last orbit.

Due to different needs, this sequence changed during the mission.
More details can be found in the following ENVISAT Phase E CAL/VAL Acquisition Plan: