Differential gps (dgps), Sources of gps error – Trimble Outdoors 132 User Manual
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DSM 132/132RS Receiver User Guide 1 9
Overview 2
2.3
Differential GPS (DGPS)
The DSM 132 receiver uses DGPS to achieve high accuracy. You can
have a DSM 132RS (this is called the reference or base station)
located at a known point. This receiver is used to determine GPS
signal measurement errors. One or more mobile receivers (called
rovers) collect data at unknown locations, while remaining within
range of the reference station. The reference station broadcasts
correction values, which are applied to the receiver positions. In this
way, errors common to the reference and rover receivers are corrected.
For more information about DGPS and the different DGPS signals
available, visit the Trimble website
(
23.1
Sources of GPS error
Autonomous (GPS only) horizontal accuracy for the Trimble
DSM 132 receiver ranges from approximately 2–9 meters (about 6–
30 ft).
The errors that cause this reduced accuracy are produced mainly by
atmospheric conditions, multipath error (that is, GPS signals bouncing
off objects before reaching the antenna), and electronic or GPS
frequency noise interference.
DGPS removes most of the errors caused by atmospheric conditions,
errors which are further minimized by the advanced design of the
DSM 132 receiver. For more information, see the section on Error
Correction on the Trimble website at