CSI Wireless Seres, Reference Manual

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Seres Reference Manual
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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 services and associated hardware and software. The Radio
Technical Commission for Maritime Services Special Committee 104 has
developed the primary DGPS standard associated with conventional DGPS,
designated RTCM SC-104 V2.2. This correction standard is used by many
correction services, including many private reference stations and DGPS
beacon systems. The Seres smart antenna supports this correction
protocol via either of its two serial ports.
In addition to the RTCM standard, the Radio Technical Commission for
Aeronautics has a differential service intended for wide area correction
services, designated RTCM SC-159. The United States Federal Aviation
Administration’s Wide Area Augmentation System (WAAS) and other
compatible Space Based Augmentation Systems (SBAS) such as the
European Geostationary Navigation Overlay System (EGNOS) and the
Japanese MT-SAT Satellite-based Augmentation System (MSAS) use this
data format. The Seres system is compatible with each of these differential
services.
1.4 Factors Affecting DGPS Accuracy
Many factors affect the positioning accuracy that a user may expect from a
DGPS system. The most significant of these influences include:
•
Proximity of the remote user to the reference station (atmospheric and orbit
errors)
•
Age of the received differential corrections
•
Atmospheric conditions at the beacon and remote user locations
•
Satellite constellation geometry, often expressed as a Dilution of Precision
(DOP)
•
Magnitude of GPS signal multipath present at the remote station
•
Quality of the GPS receiver being used at both the reference and remote
stations