09:30 〜 09:45
[MAG33-03] Overview of ALOS missions - Japanese High resolution optical and SAR satellites series
キーワード：ALOS, PALSAR, Disaster monitoring, DAICHI
Launched in January 2006 and decommissioned in April 2011, ALOS (Advanced Land Observing Satellite), also known as Daichi, was a Japanese Earth observation mission. Developed by JAXA (Japan Aerospace Exploration Agency), the mission's objectives called for high-resolution microwave imagery, for applications in cartographic mapping, regional observation, disaster monitoring and resource surveying. ALOS carried three instruments, PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping), AVNIR-2 (Advanced Visible and Near Infrared Radiometer 2) and PALSAR (Phased Array L-band Synthetic Aperture Radar). PRISM was a panchromatic radiometer that aimed to collect high-resolution stereo data for cartographic applications, while AVNIR-2 was a multispectral optical imager that aimed to monitor regional environmental land coverage and land use. PALSAR was a Synthetic Aperture Radar (SAR) instrument capable of dual-polarisation, with applications in resource exploration and environmental protection. ALOS mission was completed its operational phase on 12 May 2011 after failing due to a power anomaly. The post-ALOS program of JAXA has the goal to continue the ALOS (nicknamed Daichi) data utilization - consisting of ALOS-2 (SAR satellite) and ALOS-3 (optical satellite) in accordance with Japan’s new space program.
Launched in May 2014, the imaging radar satellite ALOS-2 (Advanced Land Observing Satellite-2), also known as Daichi-2, features an imaging microwave radar, PALSAR-2 (Phased Array type L-band Synthetic Aperture Radar-2). PALSAR-2 has a significant advantage over its predecessor PALSAR (which flew onboard ALOS) in that it has a wider range of observation modes to better suit the variety of observations tasked to the satellite. Whilst PALSAR had a minimum spatial resolution of 10 m in stripmap mode, PALSAR-2 has a minimum resolution of 3 m in the same mode. Additionally, PALSAR-2 has spotlight mode which has a resolution of 1 m x 3 m.
Advanced Land Observing Satellite-3 “DAICHI-3” (ALOS-3) is a successor of the optical mission of Advanced Land Observation Satellite (ALOS). The sensor onboard ALOS-3 is designed for an improved ground resolution (0.8 m) and wide-swath (70 km) simultaneously by expanding the size and upgrading performance compared to that of ALOS. ALOS-3 observations regularly cover all of the land areas of not only Japan but also across the whole world. ALOS-3 aims to become one of the key tools for disaster managements and countermeasures of the central and local governments; therefore, ALOS-3 is always ready for urgent observation of the affected area wherever disaster strikes. In addition to that, the system for product distribution is also developed in order to deliver images for both before and after the disaster to users swiftly. The observed data from ALOS-3 is expected to lead to progress in the various fields due to its unique imaging capabilities; it will make a significant contribution to upgrading global geospatial information and research and application for monitoring of the coastal/vegetation environment.
The Advanced Land Observing Satellite-4 (ALOS-4) is a satellite to observe the Earth's surface using its onboard phased array type L-band synthetic aperture radar (PALSAR-3) with further improved observation performance compared to the predecessor PALSAR-2 aboard the ALOS-2. The observation swath will be drastically increased from 50 km to 200 km while keeping the high resolution. Therefore, we can observe a broader area at the same time when a large-scale disaster that damages wide areas occurs, such as a huge earthquake or multiple eruptions at the same time. By using this wide swath width, ALOS-4 will increase the observation frequency to once every two weeks so that disaster prevention agencies can find abnormal changes such as unusual volcanic activity, land subsidence, or landslides at an early stage to timely warn people nearby.
This paper describes overview of ALOS missions.
Launched in May 2014, the imaging radar satellite ALOS-2 (Advanced Land Observing Satellite-2), also known as Daichi-2, features an imaging microwave radar, PALSAR-2 (Phased Array type L-band Synthetic Aperture Radar-2). PALSAR-2 has a significant advantage over its predecessor PALSAR (which flew onboard ALOS) in that it has a wider range of observation modes to better suit the variety of observations tasked to the satellite. Whilst PALSAR had a minimum spatial resolution of 10 m in stripmap mode, PALSAR-2 has a minimum resolution of 3 m in the same mode. Additionally, PALSAR-2 has spotlight mode which has a resolution of 1 m x 3 m.
Advanced Land Observing Satellite-3 “DAICHI-3” (ALOS-3) is a successor of the optical mission of Advanced Land Observation Satellite (ALOS). The sensor onboard ALOS-3 is designed for an improved ground resolution (0.8 m) and wide-swath (70 km) simultaneously by expanding the size and upgrading performance compared to that of ALOS. ALOS-3 observations regularly cover all of the land areas of not only Japan but also across the whole world. ALOS-3 aims to become one of the key tools for disaster managements and countermeasures of the central and local governments; therefore, ALOS-3 is always ready for urgent observation of the affected area wherever disaster strikes. In addition to that, the system for product distribution is also developed in order to deliver images for both before and after the disaster to users swiftly. The observed data from ALOS-3 is expected to lead to progress in the various fields due to its unique imaging capabilities; it will make a significant contribution to upgrading global geospatial information and research and application for monitoring of the coastal/vegetation environment.
The Advanced Land Observing Satellite-4 (ALOS-4) is a satellite to observe the Earth's surface using its onboard phased array type L-band synthetic aperture radar (PALSAR-3) with further improved observation performance compared to the predecessor PALSAR-2 aboard the ALOS-2. The observation swath will be drastically increased from 50 km to 200 km while keeping the high resolution. Therefore, we can observe a broader area at the same time when a large-scale disaster that damages wide areas occurs, such as a huge earthquake or multiple eruptions at the same time. By using this wide swath width, ALOS-4 will increase the observation frequency to once every two weeks so that disaster prevention agencies can find abnormal changes such as unusual volcanic activity, land subsidence, or landslides at an early stage to timely warn people nearby.
This paper describes overview of ALOS missions.