Introducing Gps And Dgps - NorthStar 961 Reference Manual

Chapter 2 - Introducing the 961/962
For details on interfacing the Northstar 490 to the 961/962,
refer to the Northstar 490 Echo Sounder Installation Manual
(GM491).
For details on interfacing the 961/962 with other devices, see
the Northstar 961/962 GPS Chart Navigator Installation
Manual (GM1901).

Introducing GPS and DGPS

This section introduces the GPS and DGPS navigation systems,
and describes how these systems relate to the Northstar 961/
962. If you're new to navigation, you may begin without
understanding anything about these navigational concepts.
However, Northstar recommends that you read this section at
some point to become familiar with the concept of GPS and
DGPS.
The United States' Global Positioning System (GPS) is now fully
What is GPS?
operational. Developed by the U. S. Department of Defense
(DOD), the GPS system comprises 21 active satellites with
three additional spares. Using these satellites, GPS encircles
the earth with navigation data.
961/962 Operations and Reference Manual, Rev. A Page 2-11