In‐orbit geometric calibration and experimental verification of the ZY3‐02 laser altimeter

ZY 3‐02 is the first Chinese earth‐observation satellite equipped with a laser altimeter, designed to assist stereo‐image mapping elevations. Launch vibrations, the space environment and other factors, both expected and unexpected, cause bias in the designed ranging and pointing of the laser altimeter, influencing its height measurement accuracy. This paper proposes an in‐orbit geometric calibration model which considers this bias as unknown systematic errors. The unknown parameters were calibrated by the minimum ranging error principle using laser spot geolocation data captured by a ground‐based laser detector array. Based on precise orbit and attitude data, the precise geolocation information of the laser footprints could be obtained. Validation experiments show that the elevation precision of the laser altimeter can reach 1 m.