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GPS APPLICATIONS AND REQUIREMENTS 35 Table 2-5 Requirements for Maritime Applicationsa Application Accuracy (2 Integrity Availability Coverage Resistance to drms) RF Interference Time to Alarmb Navigation Oceanic 1800-3700 Not 99.0% Global Moderate m (1-2 naut. specified mi.) Coastal 460 m (0.25 Not 99.7% U.S. Coasts Moderate naut. mi.) specified Harbor/ 8.0-20.0 m 6-10 s 99.7% Harbors and High Harbor Approaches Approach Inland 3.0 m 6-10 s Not yet Inland High Waterwaysc defined Waterwayc Recreational 10.0 m Not 99.9% Coasts and Moderate Boatingc specified Inland Waterways Nationwide Surveillance Vessel Traffic 10.0 m Not 99.9% Local Very High Servicesd specified Positioning Resource 1.0-3.0 m Not 99.0% Global Moderate Exploration applicable a. Integrity (1 minus PHE times PMD) and continuity of service requirements are not defined for maritime applications. Other maritime GPS requirements originate from the Federal Radionavigation Plan, pp. 2-26 through 2-28 unless annotated otherwise. b. Source of time-to-alarm requirements: U.S. Department of Commerce, National Telecommunications and Information Administration, A Technical Report to the Secretary of Transportation on a National Approach to Augmented GPS Services, p. 11. c. These values are not firmly established requirements. They are estimated useful values determined by the committee. d. Source of Vessel Traffic Services Requirements: D. H. Alsip, J. M. Butler, and J. T. Radice, Implementation of the U.S. Coast Guard's Differential GPS Navigation Service (Washington, D.C.: USCG Headquarters, Office of Navigation Safety and Waterway Services, Radionavigation Division, 28 June 1993). Challenges to Full Utilization of GPS Associated Technologies The positioning and navigation capabilities of GPS and DGPS do not solve the user's problems by themselves. For coastal and oceanic navigation, a GPS position (latitude and
