Satellite-based laser altimeters to capture accurate terrain models

Satellite-based laser altimeters to capture accurate terrain models

Specifically, those involved will be the Japan Aerospace Exploration Agency (JAXA), the Japanese national aerospace and space agency, and NTT DATA Corporation, an IT services provider.

They are looking to solve the technical challenges presented by 3D mapping, working from satellites, of forested areas, i,.e, those covered with trees and vegetation. They are looking to improve the accuracy of 3D maps used in a variety of fields such as disaster response and management.

JAXA highlights the role of LIDAR:

Spaceborne LIDAR can observe ground surface covered by forest and vegetation accurately with wide area coverage, which is difficult to be observed directly by ordinary satellite images. JAXA has experience using laser altimeters on the Hayabusa spacecraft, etc, but laser altimeters for earth observation satellite require about 1,000 times higher power due to their high orbital altitudes and atmospheric attenuation.

Joint research

JAXA will research technology to measure the height of the ground surface more accurately using space-borne laser altimeter data.

“We plan to utilize the results from this project for further research and development on space-borne laser altimeters, and contribute to greater precision in 3D mapping,” said Toshiyoshi Kimura, director of sensor system research group at JAXA.

For its part, NTT DATA has been providing 3D digital maps named, AW3D (based on PRISM data acquired by JAXA’s Advanced Land Observing Satellite), which it says enable the world’s most precise pre-produced global digital elevation models. They have been used in 2,000 projects in 130 countries.

NTT DATA will study how to best combine satellite-derived digital elevation models with the elevation of the ground surface measured by the space-borne laser altimeter.

“We are confident that we can make the best use of our 3D technology developed in creating AW3D and can contribute to developing advanced hazard maps which have so far been limited in emerging countries,” said Daiki Nozaki, head of the social innovation division at NTT DATA.

The research period will be from January 2021 to March 2022, says JAXA.

You can read more on the AW3D website.

The image below compares the approaches.

Satellite-based laser altimeters to capture accurate terrain models

Left: Estimated flood risk area based on digital surface model (before improvement)
Right:Estimated flood risk area based on digital terrain model (after improvement)

Image: (top) JAXA – Principle of space-borne laser altimeter (bottom) NTT DATA – Advanced hazard map