Encl. (1) to COMDTTNST 16577.2
USCG DGPS CONOP
meter range based on individual harbor constraints within each DGPS broadcast coverage area.
Table 2-1
Usage
Accuracy (2drme)
Availability
Harbor/Harbor Approach
8-20 meters
99.7%
ATON Positioning
10 meters
95.0%
Vessel Traffic Services
10 meters
99.9%
NOAH Near Shore Surveying
15 meters
95.0%
Army Corps of Engineering
6 meters
98.0%
Integrity is provided by continuously monitoring critical performance parameters and automatically
alarming the user when these parameters are not being met. Each DGPS broadcast will be
monitored at the point of transmission and an alarm is automatically sent to the user within ten
seconds of a fault detection. Site monitor alarm thresholds can be set to ensure user accuracy
performance is available throughout the site's assigned coverage area. The Service goal is ZERO
false alarms and ZERO missed alarms.
Reliability is a function of both the Service failure rate plus that of the user's equipment. To
maximize DGPS service reliability the operational goal is that there will be NO unforecast Service
outages. In other words, during mission planning a user can rely on having the Service available if
a broadcast outage has not been advertised.
The Broadcast Standard for the USCG DGPS Navigation Service, COMDTINST M16577.1
provides detailed specification and description of broadcast signal parameters and content. The
document's appendices include site listings and assigned coverage areas.
2.3 Service Validation
Each site's integrity monitor will collect and forward data to the Control Station. The Control
Station database will be used to calculate each broadcast's performance. This evaluation will be
done on a monthly basis. Coverage in critical waterways will be validated by analyzing data
collected from far-field monitors. Any coverage "holes" will be investigated, documented, and
solutions sought.
2.4 Customer Feedback
The Control Station will log service outages reported from users. Users with new service
requirements will be directed to contact the Program Manager within the office of Commandant
(G-N).
3