Overview; Principles Of Operation; Gps Overview - Javad Prego Operator's Manual

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Overview

Overview
The Prego is a geodetic dual-frequency, dual-system receiver manufactured by
Javad Navigation Systems, Inc. This receiver uses navigational signals from the
United States' Global Positioning System (GPS) and Russia's GLObal
Navigation Satellite System (GLONASS) to calculate positions.
The Prego is a multi-function, multi-purpose receiver intended for precision
markets.

Principles of Operation

Measuring with the right GPS receiver can provide users accurate and precise
positions.
This section gives an overview of GPS and receiver functions to help you
understand and apply GPS principles, allowing you to get the most out of your
receiver.

GPS Overview

The Global Positioning System (GPS), run by the United States Department
of Defense (DoD), is a network of up to 28 satellites orbiting the earth every
12 hours. The Global Navigation Satellite System (GLONASS), is the
Russian Federation Ministry of Defense counterpart to GPS. At any one
time, with a standard 15 degree angle, up to 10 or 12 GPS satellites are
visible from any point on earth. When a receiver can also track GLONASS
satellites, between 10 and 16 satellites are visible.
The GPS and GLONASS network has three components:
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• Space – GPS and GLONASS satellites orbiting approximately 12,000
nautical miles above Earth and are equipped with a clock and radio.
These satellites broadcast digital information (ephemerides, almanacs,
time frequency corrections, etc.).
• User – The community and military that use GPS/GLONASS receivers
and the corresponding satellites to calculate positions.
• Control – Ground stations located around the Earth that upload data,
including clock corrections and new ephemerides (satellite positions as
a function of time) to ensure the satellites work properly.
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