MSAS
Scope status
This is a source-routed system note. It is grounded in the official QZSS SBAS Transmission Service page and ICAO APAC CNS SG/24 IP15, “SBAS Status Update in Japan”.
Boundary:
- This page may describe MSAS historical operation, transition from MTSAT to QZSS, and the 2020 ICAO APAC LPV/DFMC planning signals only through Source - MSAS.
- It does not verify current post-2023 LPV operational status, airport-specific procedures, procedure minima, aircraft eligibility, or operational authorization.
- Later JCAB/MLIT/QZSS and AIP material is required before upgrading MSAS LPV or performance claims to current operational status.
Working definition
Within the current vault, MSAS is treated as the Japanese regional implementation of satellite-based augmentation with particular relevance to oceanic and terminal aviation operations.
Current in-vault references
MSAS is currently referenced in:
Source-routed profile
MSAS can currently be described in this KB as:
- Japan’s SBAS implementation, historically operational with MTSAT from 27 September 2007;
- a system whose SBAS signal generation is associated with MLIT/JCAB and whose current public transmission-service page identifies QZSS GEO transmission from April 2020;
- an Asia-Pacific SBAS system that transitioned from MTSAT to QZS-3 by the end of March 2020;
- a system with a 2020 ICAO APAC planning record for LPV and DFMC evolution;
- an important regional comparator for GAGAN and SouthPAN in Asia-Pacific implementation analysis.
These statements are source-routed through Source - MSAS.
Current claims already present elsewhere in the vault
The following claim types must remain bounded unless later source extraction supports them:
- current LPV operational status at Japanese airports;
- current MSAS service-performance metrics;
- current QZSS PRN assignments after the planned V3/V4 updates;
- any Southeast Asia service-expansion claim;
- interoperability framing with EGNOS or other SBAS providers.
Relationship to civil aviation use
In current vault structure, MSAS matters because it broadens the regional picture beyond U.S. and European deployments and helps connect SBAS to Pacific and oceanic operational contexts.
Related notes:
- SBAS in Civil Aviation MOC
- LPV-Approach-Procedure
- SBAS Integrity
- Protection Levels
- Alert Limits
- EGNOS
Relationship to standards and source scaffolds
Current source anchors that support a verified MSAS note:
- Source - MSAS — primary dedicated source anchor; verified official QZSS service-page and ICAO APAC CNS SG/24 IP15 signals.
- Source - SBAS Service Providers — service-provider family anchor.
- Source - ICAO Annex 10 Volume I GNSS SBAS — ICAO SARPs routing.
- Source - ICAO APAC GBAS-SBAS Implementation Forums — regional coordination context.
- SBAS Standards Source Matrix — claim-routing matrix for standards/source families.
Open provenance questions
- Which MSAS claims in SBAS-Systems-by-Region-MOC are descriptive placeholders versus source-grounded facts?
- Which current oceanic-operations claims need dedicated source support before being treated as conclusions?
- Should a future MSAS source stack distinguish service area, aviation use, and interoperability framing separately?
Source anchors
Current source anchors relevant to this page include:
- Source - MSAS — dedicated source note for QZSS SBAS transmission-service and ICAO APAC MSAS status-update signals.
- Source - SBAS Service Providers — institutional source-family anchor for SBAS service-provider definitions and commitments.
- Source - ICAO Annex 10 Volume I GNSS SBAS — ICAO SARPs routing.
- Source - ICAO Doc 9849 — GNSS implementation and DFMC evolution context.
- SBAS Standards Source Matrix — claim-routing matrix for standards/source families.
This page is source-routed-to-official-qzss-and-icao-apac. It may support MSAS historical, transition, and planning claims only within the date/context boundaries of Source - MSAS.