The Japanese Earth Resources Satellite-1 (JERS-1) is a joint project between the Japan Aerospace Exploration Agency (JAXA) and the Ministry of International Trade and Industry (MITI). JAXA is in charge of the satellite while MITI is responsible for the observation equipment.
JERS-1 was launched in February 1992 and ceased operation on 11 October 1998, four years more than the original two year mission plan. It observed the Earth's surface using optical sensors and a Synthetic Aperture Radar (SAR) sensor. The optical sensors collected information from eight spectral bands, while the SAR sensor operated in the L-band of the microwave wavelengths.
ACRES acquired JERS-1 SAR data at the Alice Springs ground station between September 1993 and October 1998.
| Band no. | Spectral Range (µm) | EM Region | Generalised Application Details |
|---|---|---|---|
| 1 | 0.52 - 0.60 |
visible green |
Vegetation surveys, land use, water monitoring |
| 2 | 0.63 - 0.69 |
visible red |
Chlorophyll absorption for vegetation differentiation |
| 3 | 0.76 - 0.86 |
near infrared |
Biomass surveys (nadir viewing) |
| 4 | 0.76 - 0.86 |
near infrared |
Biomass surveys (forward looking, at 15.3 degrees, to give stereo coverage with band 3) |
| Band no. | Spectral Range (µm) | EM Region | Generalised Application Details |
|---|---|---|---|
| 5 | 1.60 - 1.71 |
middle infrared |
Vegetation moisture |
| 6 | 2.01 - 2.12 |
middle infrared |
Hydrothermal mapping (eg. soils, geology) |
| 7 | 2.13 - 2.25 |
middle infrared |
Hydrothermal mapping (eg. soils, geology) |
| 8 | 2.27 - 2.40 |
middle infrared |
Hydrothermal mapping (eg. soils, geology) |
| Product Pixel Size | 18 meters |
|---|---|
| Scene Size | 75 km |
| Data quantisation | 6 bits |
The Synthetic Aperture Radar (SAR) sensor is an active microwave sensor capable of imaging the Earth regardless of time of day, cloud, haze or smoke over an area. The instrument is classified as "active" as it emits the microwave energy necessary to image the Earth's surface. In contrast, 'passive' or 'optical' sensors rely on the Sun's reflected energy to image the Earth.
An important difference between ERS SAR, RADARSAT and JERS SAR is that the latter operates in L-band, while the former two operate in the C-band part of the spectrum, making JERS SAR data well suited to land based studies.
| Frequency | 1.3 GHz |
|---|---|
| Band Width | 15 MHz |
| Band Name | L-Band |
| Wavelength | 235 mm |
| Off Nadir Angle | 35 degrees |
| Ground Resolution | 18 meters |
| Swath Width | 75 km |
| Polarisation | HH* |
* H=horizontal. |
|
| Geology | Geological structural mapping |
|---|---|
| Forestry | Tree density, Forest-type mapping |
| Soils | Soil moisture studies |
| Agriculture | Crop type discrimination |
| Land Use | Surface feature discrimination |
For further information about JERS-1 data, please contact Earth Observation Client Services.