Research for Secure Development and Success of Missions Research on Earth observation sensor system

There are many types of sensors onboard Earth observation satellites. Spaceborne remote sensing instruments are broadly categorized according to the observation techniques they employ and the electromagnetic spectrums in which they operate (optical or microwave).

Utilizing comprehensive design engineering JAXA has acquired and accumulated for a sensor system, we have been researching key technologies and sensor systems expected to be required in the next decade or two. We have also been working with internal and external organizations to devise space missions that can fully benefit from the remote sensors to be developed in the future.

An ultimate goal is to translate our research findings into Operational Earth observation missions.

The Value of Our Research

Observations of the Earth with spaceborne sensors are becoming more essential for everyday activities on the planet. Remote sensing satellites use the Sun or their own electromagnetic radiation sources to quantify and record the energy reflected back from Earth's surface. We have been researching a sensor system made up of various advanced technologies and the most appropriate satellite constellations with which to capture reflected energy in a wider electromagnetic spectrum and obtain higher precise images, spectrally and spatially.

The sensor systems will provide many benefits to the public by capturing information on the atmosphere, oceans, and landmasses. These data will play a vital role in solving natural disasters and global challenges such as climate change and abnormal weather while benefitting people's daily lives and industrial productivity.

Research Goals

Active optical sensors (LiDAR)

Multi-footprint Observation Lidar and Imager (MOLI) on the ISS-JEM

As LIDAR performs vertical direction distribution observation, which cannot be observed with a normal camera, this is a promising sensor for future 3-D observation. With observation sensor research, space vegetation LIDAR (MOLI) research is performed, in which forest height information is observed from space using LIDAR technology, which contributes to high-precision estimation of forest biomass. Additionally, we have also started an investigation into a future version of LIDAR, in which wind direction, wind speed, and ground service information is extracted based on information from aerosol altitude distribution and ground service information.

Passive optical sensors

We have been researching a larger telescope system capable of obtaining higher-resolution images from Geostationary Orbit (GEO).

Electrical wave range sensors

The ground surface cannot be observed by light if there are clouds. However with electrical waves, the ground surface can be observed as they penetrate the clouds. With observation sensor research, we are studying the basic technology and future technology of synthetic aperture radar (SAR).

Basic technology includes research into estimating physical feature values of the target based on the polarization scattering information of the target, research into holography and tomography using ground-based SAR, extensions to the observation frequency range using lower and higher frequencies than have been previously used (for radiometers, up to sub-milli/ terahertz close to light), wide-area observation SAR technology which performs simultaneous observation of multiple frequencies, and increased performance of receiver systems for marine automatic identification systems (AIS) loaded into satellites.

Elemental technologies

Prototype of a terahertz lightweight,
high-precision, composite material antenna

We have been exploring future sensor systems by researching advanced technologies such as a high-output pulse laser transmitter, Type II superlattices infrared sensor^*, non-cooled infrared sensor, terahertz lightweight, high-precision, composite material antenna, and metamaterials expected to emerge as novel sensor platforms.
We are also engaging with infrared calibration technology research, in which a method for calibrating the radiometric features of observation instruments and radiometers for the purpose of ensuring traceability is extended to thermal infrared.

^*Type II superlattice infrared sensor: a novel infrared sensor consisting of alternating layers of InAs and GaSb. The sensor is expected to exhibit good parameters such as high sensitivity and high operating temperatures comparable to those of the current HgCdTe technology.