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MSAS Performances
| MSAS | |
|---|---|
| Title | MSAS Performances |
| 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) owned and operated by the Japanese Ministry of Land, Infrastructure and Transport and the Japan Meteorological Agency (JMA). 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 Performances
MSAS for aviation use was commissioned on September 27, 2007. MSAS provide service for air navigation:
– 24 hours a day, 7 days a week.
– Operational Information is provided as NOTAM. [3]
– Use for En-route through Non Precision Approach (NPA) phase of flight (Performance improvement plan under development).
Performances are usually described in terms of accuracy, integrity, availability and continuity. The MSAS Performance Requirements vs observed performances for En-route through Non Precision Approach (NPA) phase of flight are:[4]
• Horizontal Accuracy (95%)
– Required : Less than 220m (with SA on)
– Observed value is less than 2.2m
• Integrity (Probability of HMI)
– Required : Less than 1x10-7/hour
– Fault Tree Analysis leads 0.903x10-7/hour
• Availability
– Required : More than 99.9%
– Observed : 99.926%
Due to the fact that MTSAT signal are broadcast through the majority region of Asian/Pacific, and there are two MTSAT Monitor stations in Hawaii (USA) and Camberra (Australia), the MSAS service area could be easily expanded if more GMS stations would be installed in MTSAT coverage area.
For the near future, there is a plan under development with the following priorities:
- Support LPV-200 capability (additional GMS, software improvement)
- Changes for transition to Dual Frequency (L1-L5) operations.