MSAS vs GAGAN
Scope status
This is a source-routed comparison note between MSAS and GAGAN. It compares what the knowledge base can safely say from current source notes. It does not rank the systems by performance, maturity, operational coverage, or procedure availability.
Boundary:
- It does not verify current airport/runway procedure availability.
- It does not compare service performance numerically.
- It does not infer that a historical plan, forum paper, or provider source proves current operational approval.
- It does not transfer Japan or India implementation conclusions into ASEAN without ASEAN-specific evidence.
Current authenticated comparison posture
| Dimension | MSAS source-routed posture | GAGAN source-routed posture | Safe comparison rule |
|---|---|---|---|
| Dedicated source note | Source - MSAS | Source - GAGAN SBAS Operation | Compare source posture before comparing system capability |
| Current public source basis | Official QZSS SBAS Transmission Service material plus ICAO APAC CNS SG/24 IP15 | ICAO APAC ITF/7 IP05b plus AAI GEO FAQ signals | Both have system-specific public evidence, but the evidence types are not identical |
| Geographic role | Japan / QZSS / Asia-Pacific comparator | India / low-latitude regional comparator | Geography is a source-context signal, not proof of transferable ASEAN feasibility |
| Operational-procedure status | Current post-2023 LPV operational status remains bounded pending later JCAB/MLIT/QZSS/AIP extraction | ITF/7 contains GAGAN procedure-count signals, but current procedure minima and operational details require DGCA/AAI/AIP evidence | Do not compare procedure inventories without current equivalent procedure sources |
| Standards layer | Requires Annex 10 / DO-229 / procedure-design routing for technical claims | Requires Annex 10 / DO-229 / procedure-design routing for technical claims | Do not let service-provider notes replace standards or regulator sources |
What can be said safely now
- MSAS is source-routed through Source - MSAS.
- GAGAN is source-routed through Source - GAGAN SBAS Operation.
- Both are useful Asia-focused comparator systems in Asia-Pacific SBAS Implementation Patterns.
- Both require further regulator/AIP/procedure extraction before operational procedure availability is treated as verified.
What remains uncertain
- Whether current MSAS LPV/APV operational availability is documented by current official Japanese regulator/AIP sources.
- Whether current GAGAN procedure inventories, minima, aircraft/operator eligibility, and approval conditions are fully represented by DGCA/AAI/AIP sources.
- Whether both systems have equivalent official performance/service-volume reports suitable for a comparative table.
- Whether ASEAN implementation analysis can use either system as more than a bounded comparator.
Best next support targets
- Current JCAB/MLIT/QZSS and AIP evidence for MSAS procedure status.
- Current DGCA/AAI/AIP evidence for GAGAN procedure publication and approval conditions.
- Service-provider performance/service-volume reports for both systems.
- SBAS Operational Validation Dashboard for deciding when a claim graduates from source-context to operational-use evidence.