Select > System > Satellite Positioning.

Source

Allows you to select the preferred source for GPS data.

Speed Filter

Averages the speed of your vessel over a short period of time for smoother speed values.

WAAS/EGNOS

Turns on or off WAAS data (in North America) or EGNOS data (in Europe), which can provide more-accurate GPS position information. When using WAAS or EGNOS data, the device may take longer to acquire satellites.

Positioning Mode > GPS Only

The GPS source uses only GPS satellites for position data.

Positioning Mode > GPS and GLONASS

The GPS source uses both GPS satellites and GLONASS (Russia satellite system) for position data. When the system is used in situations with poor sky visibility, GLONASS data can be used in combination with GPS to provide more accurate position information.

Positioning Mode > Multi-Constellation

The GPS source uses GPS data from all available satellite constellations for position data.

Positioning Mode > Multi-Constellation and Multi-Frequency

The GPS source uses GPS data from all available satellite constellations as well as both L1 and L5 frequencies for position data.