Speed over ground
The speed over ground (v g ) is the movement of a ship or aircraft relative to the ground (ground or surface of the earth). It is - along with the price (of magnetic or geographical direction ) - the basis of dead reckoning ( Engl. Dead reckoning ), the joining distance covered spans for accurate positioning.
aviation
The ground speed (as speed over ground referred) is in the flier language usually also English groundspeed or groundspeed called and GS , respectively. The movement of an aircraft relative to the medium - the earth's atmosphere - is referred to as its own or airspeed .
shipping
In shipping, the speed over ground according to DIN 13312 Navigation from February 2005 is always referred to as travel over ground ; the “intended speed of advance ” ( SOA) and the “averaged speed made good ” ( SMG) both have the standard-compliant symbol FüG in German; The English term speed over the ground (SOG), on the other hand, means the distance measured over the ground while driving in the vehicle. Water currents in the waters traveled (especially in rivers or with ocean currents such as the Gulf Stream ) influence the FüG.
Ways to determine
The ground speed can be determined in several ways, e.g. B .:
- a log (ships) and subsequent consideration of the offset by wind or current
- on ships with the Doppler log (also determines the drift )
- from external navigation methods , e.g. B. with GPS