COBHAM SAILOR 6560 - Chapter 1 Introduction; Introduction to GNSS and DGNSS

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Chapter 1
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Introduction
Introduction 1
This chapter introduces the GNSS/DGNSS Receiver and gives an overview
of the system and services. It has the following sections:
• Introduction to GNSS and DGNSS
• The GNSS or DGNSS system
• System components
Introduction to GNSS and DGNSS
Overview
A GNSS receiver processes the signals transmitted by the satellites of Global
Navigation Satellite Systems (GNSS). The GNSS receiver determines the
position, velocity, and precise time by processing the signals broadcast by
GNSS satellites.
A DGNSS receiver (Differential GNSS) is an enhancement to a GNSS
receiver. It can utilize a global network of ground-based reference stations
for improved position accuracy. The ground-based reference stations
compare their known fixed positions with the positions calculated from the
received GNSS satellite signals. The differences are transmitted via radio
beacons to the DGNSS Receiver, which can use them to calculate a more
precise position. In order to be able to apply high-quality corrections, the
selected reference station must be near the DGNSS receiver to ensure that
they both observe roughly the same GNSS satellites.