User guide

Global Positioning System (GPS)
Rev 2.3 Feb.12 207
National Marine Electronics Association (NMEA)
National Marine Electronics Association (NMEA) is a protocol by which marine
instruments and most GPS receivers can communicate with each other. NMEA
defines the format of many different GPS message (sentence) types, which are
intended for use by navigational equipment.
Example of a tracking application using NMEA:
• Microsoft Streets and Trips
Tip: For more information on the AirLink device supported NMEA message formats,
please refer to the Appendix.
Trimble ASCII Interface Protocol (TAIP)
Trimble ASCII Interface Protocol (TAIP) is a digital communication interface based
on printable ASCII characters over a serial data link. TAIP was designed
specifically for vehicle tracking applications but has become common in a number
of other applications, such as data terminals and portable computers, because of
its ease of use.
Example of a tracking application using TAIP:
• DeLorme Street Atlas USA
Tip: For more information on TAIP message formats, refer to the Appendix and to the
Sierra Wireless MP 3G Modem TAIP Reference.
Datum
The GPS datum is the method of ascertaining the position of the GPS device
using a specific reference point location. The datum used can influence the
accuracy of the GPS positioning.
In addition to different reporting protocols, the AirLink device supports the most
widely used GPS datum:
• WGS84
• NAD83
• NAD27
Before Configuring GPS
To decide what configuration you need for your AirLink device, there are some
fundamental considerations you should determine:
•Protocol: What is the GPS protocol used by your tracking application and
what type of reports will you need?
•Datum: What is the datum supported by your tracking application?
• Dynamic IP Address: Will you need DNS support to handle a dynamic IP
address account?