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MSAS Space Segment
| MSAS | |
|---|---|
| Title | MSAS Space Segment |
| Author(s) | GMV. |
| Level | Basic |
| Year of Publication | 2011 |
The Multi-functional Satellite Augmentation System (MSAS) is the Japanese SBAS System: a GPS Augmentation system with the goal of improving its accuracy, integrity, and availability, and that uses the Multifunctional Transport Satellites (MTSAT). Tests during Initial Operational Phase were accomplished successfully, and MSAS for aviation use was declared operational on September 27, 2007.[1]
GPS signals are received at the MSAS Ground Monitor Stations and MSAS Monitor & Ranging Stations. These stations check operational status of GPS, and transmit GPS data to Master Control Stations that analyze GPS error and ionospheric delay. Then, these Master stations compute Augmentation information and broadcast it to GEO MTSAT (Multi-functional Transport Satellite)[2] satellites. Those satellites, MTSAT, rebroadcast the correction messages back to Earth, where MSAS-enabled GPS receivers use the MSAS corrections to compute a reliable and accurate position.
MSAS Space Segment
The space segment consists of two geosynchronous communication satellites (GEO): the Multifunctional Transport Satellites (MTSAT), with navigation payloads which broadcast the correction messages generated by the Master Stations for reception by the User segment. These two satellites are not only devoted to navigation, but also to meteorological/weather purposes.
They are geostationary satellites owned and operated by the Japanese Ministry of Land, Infrastructure and Transport and the Japan Meteorological Agency (JMA), and provide coverage for the hemisphere centred on 140° East; this includes Japan and Australia who are the principal users of the satellite imagery that MTSAT provides. They replace the GMS-5 satellite, also known as Himawari 5. They can provide imagery in five wavelength bands — visible and four infrared, including the water vapour channel. The visible light camera has a resolution of 1 km; the infrared cameras have 4 km (resolution is lower away from the equator at 140° East). The spacecraft have a planned lifespan of five years. MTSAT-1 and 1R were built by Space Systems/Loral. MTSAT-2 was built by Mitsubishi. [3]
MTSAT-1R (also known as Himawari 6) was successfully launched on a H-IIA on February 26, 2005 and became partially operational on June 28, 2005 — the aviation payload was not functional as two MTSATs are required for air traffic control. MTSAT-2 (also known as Himawari 7) successfully launched on February 18, 2006 and is positioned at 145° East. The weather functions of MTSAT-2 were put into hibernation until the end of MTSAT-1R’s life (5 years from launch). The transportation and communication functions of MTSAT-2 will be utilized prior to that time.
Both satellites, MTSAT-1R and MTSAT-2, are controlled by Kobe MCS station and Hitachiota MCS, respectively.
| Satellite Name & Details | NMEA / PRN | Location |
|---|---|---|
| MTSAT-1R | NMEA #42 / PRN #129 | 140°E |
| MTSAT-2 | NMEA #50 / PRN #137 | 145°E |