User`s guide

Chapter 2 - NAVSTAR GPS Overview

The navigation message consists of a 50 bit per second data stream containing information

enabling the receiver to perform the computations required for successful navigation. Each

satellite has its own unique C/A code that provides satellite identification for acquisition and

tracking by the user.

There are several GPS related sites on the World Wide Web that are excellent sources of

information about GPS and the current status of the satellites. Several are listed below:

Additional Information Sources

U.S. Coast Guard Navigation Center - Civilian GPS service notices, general system

information, and GPS outage reporting:

http://www.navcen.uscg.gov/gps/default.htm

U.S. Naval Observatory - USNO time service information and links to USNO timing and other

useful sites:

http://tycho.usno.navy.mil/

NTP Homepage - Information on using Motorola GPS receivers for precision network timing in

both Windows and Linux environments.

http://www.ntp.org

NAVSTAR GPS Homepage - General GPS information and links to other useful GPS sites:

http://gps.losangeles.af.mil/

National Marine Electronics Association (NMEA) - For information on the NMEA protocol

specification:

http://www.nmea.org/

Radio Technical Commission Marine (RTCM) - For information on the RTCM specification for

DGPS corrections:

http://www.rtcm.org

General GPS Information

http://www.gpsworld.com/gpsworld

Helpful equations, code snippets, and other useful information:

http://www.colorado.edu/geography/gcraft/notes/gps/gps_f.html

Oncore GPS Information - For the latest information on Oncore GPS products:

http://www.motorola.com/gps

Motorola GPS Products - M12+ User's Guide Revision 6.X 09FEB05