MIDLAND Geopoint Box SMS - Manual (Page 18)

17
General Information
If the GPS receiver reports that a three dimensional satellite FIX is available (3D FIX), it means that the signal
is optimal.
In some climatic or structural conditions, (when it is foggy, clouded, ... or inside buildings, tunnels, ...) partial
or total GPS signal coverage may be missing. In this case, some functions may not be available.
Notwidstanding the Selective Availability (SA) introduced by United States of America for military reasons, the
margin of error on the GPS data is only limited but not deleted. The location data can contain inaccuracies
caused by external factors as errors in the orbit and in the satellites clock, climatic conditions and multipath
effects.