MSAS

SATELLITES IN GPS

1. MSAS MULTI-FUNCTIONAL SATELLITE AUGMENTATION SYSTEM

2. WHAT IS MSAS MTSAT Satellite Augmentation System (MSAS) is a Japanese SBAS (Satellite Based Augmentation System), i.e. a satellite navigation system which supports differential GPS (DGPS) designed to supplement the GPS system by reporting (then improving) on the reliability and accuracy of those signals . providing a service of horizontal guidance for En-route through Non-Precision Approach.

3. The MTSAT Satellite Augmentation System (MSAS) is the Japanese Satellite Based Augmentation System (SBAS) System:[1] a GPS Augmentation system with the goal of improving its accuracy, integrity, and availability, and that uses the Multifunctional Transport Satellites (MTSAT) owned and operated by the Japanese Ministry of Land, Infrastructure and Transport and the Japan Meteorological Agency (JMA) First tests were accomplished successfully, and MSAS system for aviation use was declared operational in September 27, 2007 .

4. MSAS CONFIGURATION OVERAL

5. MSAS works by processing GPS data collected by a network of reference stations to generate the SBAS message which is uploaded to the GEO satellites. The GEO satellites broadcast this information to the user receivers, which compute the aircraft positioning and inform on potential alert messages. The main layers of MSAS architecture MSAS Ground Segment: The ground segment is composed of four Ground Monitor Station (GMS) that collect information on the GPS and MTSAT signals. Then, the GMS send their data to two Master Control Station (MCS) in Kobe and Hitachiota, that compute precise differential corrections and integrity bounds and send them to the MTSAT satellites for rebroadcast to the User Segment. The MSAS Ground Segment is completed with two Monitor and Ranging Station (MRS), whose purpose is primarily the correct orbit determination of the MTSAT satellites. MSAS Space Segment: The space segment consists of two geosynchronous satellites (GEO): the Multifunctional Transport Satellites (MTSAT). These satellites are used also for meteorological purposes. Their navigation payloads are in charge of broadcasting the correction messages generated by the Master Control Stations for reception by the User Segment. MSAS User Segment: The user segment is the GPS and SBAS-enabled receiver, which uses the information broadcast from each GPS satellite to determine its location and the current time, and receives the MSAS corrections from the Space Segment. HOW MSAS WORKS

6. 2 GEO, 2 MCS (Master Control Station), 4 GMS (Ground Monitor Station), and 2 MRS; MCS also has GMS function; MSAS has 6 domestic monitor stations. 2 MRS (Monitor and Ranging Station) for GEO positioning for GEO ranging function. Ranging Signals MTSAT-1R GPS Satellites Ground Network Naha GMS Fukuoka GMS Tokyo GMS Sapporo GMS Hitachi-Ota MCS (and GMS) Kobe MCS (and GMS) Hawaii MRS Australia MRS Users MTSAT-2 Augmentation Signals 6 GMS in Japan Canberra MRS Hawaii MRS MSAS Monitor Stations

7. MSAS Performances MSAS for aviation use was commissioned on September 27, 2007. MSAS provides service for air navigation with the following characteristics 24 hours a day, 7 days a week. Operational Information is provided as notice to airmen (NOTAM ). Use for En-route through Non Precision Approach (NPA) phase of flight, horizontal guidance only. Service over the Fukuoka Flight Information Region SIGNAL STRUCTURE Frequency : L1 = 1575.42 MHz Bandwidth: L1 not equal to 2.2 MHz

8. Regional Air carriers Fire Fighters Government MSAS APPLICATIONS

9. Contents 1. Accuracy 2. Integrity 3. Continuity 4. Availability

10. ACCURACY Required: Less than 220 m (with SA on) Observed value is less than 2,2 m

11. INTEGRITY Required: less than 1 x 10^-7/hour Faulty Tree Analysis leads 0.903 x 10^-7/hour

12. Availability Required: more than 99.9% Observed: 99.926%