China achieved an important breakthrough in space-based active earth mapping technology when it released data acquired by the the laser altimeter onboard the Gaofen-7 satellite on Dec. 10, 2019. The data launched a new era by achieving global stereo mapping on a scale of 1:10,000. 

The laser altimeter is China’s first full-waveform laser surveying and mapping payload to be put into service. Its key technology breakthroughs include laser positioning with arc-second precision, submetric absolute elevation acquisition, high optical beam quality and high-powered laser emissions. All core components of the laser altimeter are autonomous and controllable. At the same time, the laser altimeter creatively adopted composite measurement technology using active and passive optics and, for the first time in the world, simultaneously obtained high-precision elevation data and high-quality images of ground objects. Its digital waveform resolution was 7.5cm – showing better performance than similar instruments in other countries. 

This technology will play a key role in obtaining high-precision three-dimensional topographic data from un-mapped areas in China. It also has great prospects in important areas such as territorial mapping, residential construction planning and national resource statistics, among others. 

The Gaofen-7 laser altimeter