3DM
®
-GX5-10
User Manual
4.2
Sensor Reference Frames
4.2.1
Geodetic Frame
The World Geodetic System is the standard for cartography and navigation. The latest revision,
WGS84, is the reference coordinate system for GPS. It also calculates the magnitude of the local
gravity vector using the WGS84 reference formulas.
The WGS coordinates are latitude (φ), longitude (λ), and height (h) above the reference ellipsoid.
Latitude ranges from -90 degrees at the South Pole to 90 degrees at the North Pole. Longitude
ranges from -180 to 180 degrees, with 0 degrees being the prime meridian. The -180/180 degree
switchover occurs in the middle of the Pacific Ocean and includes a section of the International Date
Line. The model takes into account the oblateness of the Earth’s surface.
A point (P) on or above the Earth in the WGS84 coordinate system is notated as: latitude (φ),
longitude (λ), and height above the reference ellipsoid (h).
Figure 16 -
World Geodetic System (WGS84) Reference Ellipsoid
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