AGCO Valtra Smart farming, Operator'S Manual

Page: 18 / 170

3.1 Defintions
3.1.1 GNSS and correction signal
GNSS (Global Navigation Satellite System) is a global navigation satellite system designed for position
determination and navigation using satellite signals and signals received from pseudolites (terrestrial
transmitters which emit signals like those of a satellite).
GNSS satellites communicate their exact position and time via radio. For position determination a receiver
has to be supplied with signals from at least four satellites simultaneously. The four signal propagation
times (from the satellites to the receiving aerial) are then calculated in the receiving device. This is used to
determine the current position.
Stationary receiving stations improve positional accuracy by transmitting correction signals (DGPS) to
users:
• With geostationary satellites such as the European EGNOS, the American WAAS and various other
providers
• Terrestrially with a base station or RTK network
3.1.2 Satellite reception
It is possible that for example dense trees, copses,
buildings and high-voltage power lines block the
GNSS signal and the correction signal.
(1) A blocked signal
1
GUID-02BD1980-0148-4AC6-B380-3041E2813FD3-low.svg [Low]
Fig. 1
The GNSS signal and correction signal are not
available when the satellite is less than 5 to 8
degrees above the antenna level.
NOTE:
The correction signal satellite is geostationary
above the equator.
(1) Small signal angle
1
GUID-0EBD138B-4696-4A3D-822C-30E0A273D2A3-low.svg [Low]
Fig. 2
[V]
GUID-AF9BC585-62F3-4656-B531-687FA4CFF466 [V3]
GUID-A9DA2B32-4F5D-4306-86C5-AA6B330C38B4 [V3]
3. Signal definition and characteristics
Smart farming 23
39 924 21 5