User`s guide

Chapter 5 - I/O Commands
COMBINED POSITION MESSAGE (@@Ga)
Applicability: M12+ Positioning and Timing Receivers
This message allows the user to enter an initial position estimate.
If the receiver is computing a 2D fix, the receiver will ignore any attempts to change the latitude
and/or longitude using this command. If the receiver is computing a 3D fix, it will also ignore any
attempts to change height with this command. Under these conditions the receiver will respond
with coordinates of its currently calculated location.
If the user inputs the @@Ga Combined Position message along with the @@Gb Combined Time
and @@Cb Almanac Input messages to a defaulted receiver, the receiver will be in a ‘Warm
Start’ condition, resulting in a rapid TTFF. This procedure should be used with care. If any of the
data is erroneous, the TTFF time may actually be EXTENDED instead of shortened.
Default Values: Latitude = 0º
Longitude = 0º
Height = 0m (GPS Height)
Legacy Code Compatibility: The @@Ga command was implemented in an identical fashion on
the Motorola M12 Oncore receiver.
Earlier ONCORE receivers such as the VP, GT+, SL, and UT+ utilized three different messages
to convey this information:
@@Ad – Latitude
@@Ae – Longitude
@@Af - Height
Motorola GPS Products - M12+ User's Guide Revision 6.X 09FEB05
138