User`s guide

Chapter 5 - I/O Commands

IONOSPHERIC CORRECTION SELECT COMMAND (@@Aq)

Applicability: M12+ Positioning and Timing receivers

The user has the flexibility of turning the GPS ionospheric and/or tropospheric correction models

on or off. The models do a reasonable job of taking out the range error induced by the earth’s

ionosphere and troposphere by using algorithms and parameters transmitted to the users by the

satellites.

For some applications, such as differential systems, the models should be disabled since the

differential corrections include the errors.

Default modes: Ionospheric model enabled

Tropospheric model disabled

Legacy Code Compatibility: The @@Ap command has been implemented in a similar fashion on

virtually all Motorola Oncore receivers. Some earlier receivers did not support all four of the

modes available with the M12+, but the message structure is identical.

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