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Requirements
The overall maritime requirements are defined in the IMO (International Maritime Organisation) regulation A.915 (22), "Revised maritime policy and requirements for a future Global Navigation Satellite System (GNSS) , January 22nd 2002:
Maritime – Minimum User Requirements for General Navigation |
Application |
System Level Parameters |
Service Level Parameters |
Absolute Accuracy |
Integrity |
Availability (% per 30 days) |
Continuity (% over 3 hours) [1] |
Coverage |
Fix interval (s) [2] |
Horizontal (m) |
Alert Limit (m) |
Time to Alarm (s)
[2] |
Integrity Risk (per 3 hours) |
1 |
Ocean navigation |
10 |
25 |
10 |
10-5 |
99.8 |
N/A |
Global |
1 |
2 |
Coastal |
10 |
25 |
10 |
10-5 |
99.8 |
N/A |
Global |
1 |
3 |
Port Approach and Restricted Waters |
10 |
25 |
10 |
10-5 |
99.8 |
99.97 |
Regional |
1 |
4 |
Inland Waterways |
10 |
25 |
10 |
10-5 |
99.8 |
99.97 |
Regional |
1 |
[1] Continuity is not relevant to ocean and coastal navigation
[2] More stringent requirements may be necessary for ships operating above 30 knots
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