1. (radio-navigation) The coverage provided by a radio-navigation system is that surface area or space volume in which the signals are adequate to permit the user to determine position to a specified level of accuracy.
Coverage is influenced by system geometry, signal power levels, receiver sensitivity, atmospheric noise conditions and other factors which affect signal availability.
2. (general) "feature that acts as a function to return values from its range for any direct position within its spatial, temporal, or spatiotemporal domain.
EXAMPLE: Examples include a raster image, polygon overlay or digital elevation matrix.
NOTE: In other words, a coverage is a feature that has multiple values for each attribute type, where each direct position within the geometric representation of the feature has a single value for each attribute type."
1. ICAO Document 9613, Manual on Required Navigation Performance (RNP), Appendix A
2. ISO Standard 19123 (Geographic Information - Schema for coverage geometry and functions) (2005)