A GPS Overview
50 MiLLennium Command Descriptions Manual
A GPS OVERVIEW
The Global Positioning System (GPS) is a satellite navigation system capable of providing a highly accurate,
continuous global navigation service independent of other positioning aids. GPS provides 24-hour, all-weather,
worldwide coverage with position, velocity and timing information.
The system uses the NAVSTAR (NAVigation Satellite Timing And Ranging) satellites which consists of 24
operational satellites to provide a GPS receiver with a six to twelve-satellite coverage at all times depending on the
model. A minimum of four satellites in view allows the GPSCard to compute its current latitude, long itude, altitude
with reference to mean sea level and the GPS system time.
Figure A-1 NAVSTAR Satellite Orbit Arrangement

A.1 GPS SYSTEM DESIGN

The GPS system design consists of three parts:
The Space segment
The Control segment
The User segment
AGPS OVERVIEW