Well-calibrated measurements

Image of the month - February 2002

The laser used to calibrate Jason-1 after its installation at Aspretto near Ajaccio, Corsica, January 12, 2001.
(Credits Cerga/Cnes).

Laser calibration of Jason-1 orbit, January 18, 2002 (Credits Cerga/Cnes)


Calibration is a key phase in the early stages of a satellite's life. For Jason-1, this phase will involve calibrating all ground processing systems, algorithms, data, and associated errors by comparing them with external measurements and by statistical analysis. The satellite-to-surface range, associated corrections, the satellite's orbit, wind speed, and wave heights will thus be verified.
This calibration process, which provides information on instrument bias and an estimate of system component drift, will continue on a weekly basis throughout the mission.

For this calibration, in-situ sites have been installed. A laser station has been installed at the Corsica site, in particular. It gives a very precise determination of the satellite path when in visibility. This able a better inter-comparison between satellite radar and tide gauges sea level determinations.