User`s guide

Chapter 5 - I/O Commands
Motorola GPS Products - M12+ User's Guide Revision 6.X 09FEB05
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GPGSA (GPS DOP AND ACTIVE SATELLITES)
This command enables the GPGSA DOP and Active Satellites message and determines the rate
at which the information is transmitted. The periodic rate field (yyyy) instructs the receiver either
to output this message once (polled), or to output this message at the indicated update rate
(continuously). Once the receiver is set to continuous output, the continuous flow can be stopped
by sending a one-time (polled) output request. The receiver will output the response one final
time, and then terminate any further message outputs. The value of the periodic rate is retained
through a power cycle only if battery backup power is applied.
If the receiver is not computing a position fix (mode field is '1' ), then the xDOP fields (p.p, q.q, r.r)
will be nulled. If the receiver is computing a 2-D position fix (mode field is '2'), then the PDOP field
(p.p) and the VDOP field (r.r) will be nulled. Only satellite IDs used in the solution are output; the
remaining satellite ID fields will be nulled.