Gps Position And Gps-Msl Altitude - Garmin G1000 Pilot's Manual

GPS POSITION AND GPS-MSL ALTITUDE

The G1000 GPS receiver provides the horizontal position and altitude. GPS altitude is derived from satellite
position. GPS altitude is then converted to a mean sea level (MSL)-based altitude (GPS-MSL altitude) and is used
to determine terrain and obstacle proximity. GPS-MSL altitude accuracy is affected by satellite geometry, but is
not subject to variations in pressure and temperature that normally affect pressure altitude sensors. GPS-MSL
altitude does not require local altimeter settings to determine MSL altitude. It is a reliable MSL altitude source.
Terrain and obstacle databases are referenced to MSL. Using the GPS position and altitude, the Terrain Proximity
feature portrays a 2D picture of the surrounding terrain and obstacles relative to the position and altitude of the
aircraft. GPS position and GPS-MSL altitude are used to calculate and predict the aircraft' s flight path in relation
to the surrounding terrain and obstacles. In this way, the pilot can view predicted dangerous terrain and obstacle
conditions.
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In Figure 6-44, terrain elevation is shown relative to the aircraft altitude. Obstacle colors are displayed in Table
6-4. Terrain and obstacles that are above the aircraft or less than 100 feet below the aircraft altitude are shown
in red. Those between 100 feet and 1000 feet below the aircraft altitude are shown in yellow. Terrain lower than
1000 feet below the aircraft altitude is shown in black. Obstacle data is displayed in gray when the difference in
aircraft altitude and obstacle height is greater than 1000 feet.
Terrain Color
190-00592-02 Rev. A
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Figure 6-38 Terrain Proximity Indications and Colors
Red Terrain above or within 100 ft below the aircraft altitude
Yellow Terrain between 100 ft and 1000 ft below the aircraft altitude
Black Terrain more than 1000 ft below the aircraft altitude
Table 6-4 Terrain Proximity Colors
Garmin G1000 Pilot's Guide for the Diamond DA40/40F
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Terrain Location
HAZARD AVOIDANCE
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