CSI Wireless DGPS MAX, Reference Manual

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DGPS MAX Reference Manual
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satellite distance measurement in order to correct for errors present in
the system.
1.2.2 Real-Time DGPS
The base station transmits the range error corrections to remote receivers
in real-time. The remote receiver corrects its satellite range measurements
using these differential corrections, yielding a much more accurate position.
This is the predominant DGPS strategy used for a majority of real-time
applications. Positioning using corrections generated by DGPS
radiobeacons will provide a horizontal accuracy of 1 to 5 meters with a
95% confidence. More sophisticated, short-range DGPS systems (10 to
15 km) can achieve centimeter-level accuracy, but are expensive and often
limited to precise survey applications due to technical constraints on their
use.
1.3 DGPS Format
For manufacturers of GPS equipment, commonality is essential to maximize
the utility and compatibility of a product. The governing standard
associated with GPS is the Interface Control Document, ICD-GPS-200,
maintained by the US DoD. This document provides the message and
signal structure information required to access GPS.
Like GPS, DGPS data and broadcast standards exist to ensure compatibility
between DGPS networks, and associated hardware and software. The
Radio Technical Commission for Maritime Services Special Committee 104
has developed the primary DGPS standard associated with radiobeacon
DGPS, designated RTCM SC-104 V2.2.
Various broadcast standards may exist for the beacon networks installed
internationally, controlled by their respective operating authority. The
United States Coast Guard maintains a broadcast standard that is
referenced in the Further Reading section of this manual.