ashtech DG16 Reference Manual page 47

See "POS: Position Message" on page 265 for more information on this
command.
4. If interfacing through port A, type $PASHS,NME,SAT,A,ON,1 and press
<Enter>. This command tells the DG16 to return locked satellite information
through port A at a set rate. The response message output rate is 1 Hz
(default):
$PASHR,SAT,03,03,103,56,60,U,23,225,61,39,U,16,045,02,21,U*6E
The data string contains the number of satellites locked plus the elevation,
azimuth, and signal strength for each locked satellite, and also indicates
whether a given satellite is used (U) or not used (-).
See "SAT: Comprehensive Satellite Tracking Data" on page 272 for more
information on this command.
Getting Started 27