Sometimes shown in a display field on a PSAP's CPE. Contains the uncertainty (in meters) associated with the lat/long.
Uncertainty is a measurement, in meters, which is similar to a radius from the x,y but should not be treated strictly as a
radius. For some PDEs, uncertainty is expressed as a radius; however, for other PDEs (particularly network based PDEs),
it is an expression of an elliptical area from the center point and is not literally a radius in any direction. Uncertainty
should be used by the PSAP as an indication of the accuracy of the lat/long for the caller. A small uncertainty (for
example, 25 meters or less) indicates that the x,y is very good. A larger uncertainty (for example, 200 meters) indicates
that caller may be further away from the x,y on the screen.
If the COS indicates that the x,y is Phase I, uncertainty should be ignored