Sierra Wireless AirLink MP890, Руководство пользователя

Страница: 40 / 67

AirLink MP User Guide
32 2130795
For more information about GPS, see the Primer on GPS Operations (document
#2130313) on the Sierra Wireless web site,
www.sierrawireless.com
.
GPS protocols and commands
Note: The “MP 3G
Modems TAIP Reference
manual” (document
#2130312) provides a
description of the TAIP
commands that can be
used with the MP modem.
This is available at
www.sierrawireless.com
.
Information about Trimble
GPS modules, including
more documentation on
TAIP commands, is
available at
www.trimble.com
.
More information on
NMEA message standards
is available at
www.nmea.org
.
The GPS module supports two methods of reporting navigational information,
using either the TAIP (Trimble ASCII Interface Protocol) or NMEA (National
Marine Electronics Association) protocols. The GPS module is pre-configured for
TAIP. If you are using a GPS application that requires data to be reported
according to the NMEA protocol, the MP modem must be reconfigured using an
AT command. (See the
MP 3G Modems AT Command Reference manual
(document #2130810.)
NMEA is a reporting protocol only, while TAIP provides the ability to send
commands to the module to query for information and configure reports. When
the MP modem is set for TAIP, commands can be sent to the MP modem in these
ways:
• Using AceView
• Using AT commands
TAIP commands can be used to:
• Query the MP modem for its current position, heading, and speed
• Enable and disable automatic reporting of GPS data, and set the interval at
which automatic reports are sent
• Configure the format of reports
GPS display in AceView
To view AceView’s GPS Display window, which reports latitude, longitude, speed,
direction, altitude, and local and UTC time
1
, select
Tools > Display GPS
or double-
click the GPS icon on the main AceView window.
From a cold start (where the MP modem is powered on with no stored
navigational data), it may take up to 39 seconds for the GPS module to obtain
satellite fixes and begin reporting.
1. UTC replaces Greenwich Mean Time as the basis for standard time
throughout the world. UTC, which uses atomic measurements rather than
the Earth’s rotation, is the equivalent of mean solar time at the prime merid ‐
ian (0° longitude).