Development of a calibration facility for small EO sat as PROBA V

Today more and more small Earth Observation satellites are under development. All of them are very ambitious and needs accurate on ground calibration. A typical case is PROBA V payload where to ensure the continuity of Vegetation data, an instrument responding to the same user requirements as Vegetation was build, but with an overall mass of about 30 kg, instead of the 130 kg of VGT. Because a very high level of performances is required these need to be verified and calibrated with a high level of accuracy. This paper presents the calibration facility developed for the testing of small Earth Observation payloads as PROBA V. The facility needs to address the geometrical and radiometric calibration of the payload. To achieve this, a 400 mm clear aperture off axis collimator with a dedicated focal plane is developed for the geometrical calibration and a 300 mm integrating sphere calibrated at the LNE is used for the radiometric calibration. To access all the Field Of View, the payload is placed on a rotating tip tilt table allowing rotation of +/- 180° for across track Field Of View scanning and +/-10° for along track scanning. The payload is surrounded by thermal shroud to provide the required thermal environment.