Ziyuan-3 Laser Altimeter

The Ziyuan-3 laser altimeter is a single-beam spaceborne laser altimeter series flown on successive Ziyuan-3 (ZY-3) satellites: ZY-3 02 (launched 2016-05-30), ZY-3 03 (launched 2020-07-25), and ZY-3 04 (launched 2025-12-16). Manufactured by the China Academy of Space Technology (CAST) and operated by CRESDA and CNSA, each instrument operates at 1064 nm.^[1][2]

The design across the series uses a single nadir-pointing beam to provide terrain elevation profiles complementing the stereo optical cameras on each platform. For ZY3-02, the footprint diameter is 50 m in the tabulated design specification and approximately 75 m in the same characterisation, with the latter figure likely representing the effective nadir footprint.^[1] ZY3-02 operates at an orbital altitude of approximately 484-500 km. Stereo imagery from ZY3-02 integrated with altimeter elevation data has been applied to terrain modelling.^[3]

Waveform recording capability differs across the series. ZY3-02 records ranging information without full-waveform data.^[1] ZY3-03 represents a second-generation design with improved performance and underwent pointing bias calibration following its launch.^[2] ZY-3 04, launched in December 2025, is the fourth satellite in the ZY-3 series and the third to carry a laser altimeter.^[4][5]