Specifications

Differential and RTK Operations 37
Differential and RTK
may also be entered directly into the remote unit, using the $PASHS,CPD,POS and
$PASHS,UBP commands. This reduces bandwidth requirements by obviating the
need for messages 3 and 22.
Base Station Antenna Offset
If you set up the base station antenna over a known, surveyed point, you may enter the
position of the surveyed point and the offset from this point to the antenna phase
center. Or you may enter the phase center directly.
If you are using 3 & 22, or BPS:
• At the base station, enter the phase center of the antenna directly using
$PASHS,POS and setting $PASHS,ANR,OFF, or
• At the base station, enter the surveyed reference point using
$PASHS,POS and enter the antenna offset using $PASHS,ANT and
$PASHS,ANR, ON (or keep it at CPD if running CPD mode only, not
combined).
If you are entering the base station position directly at the remote:
• At the remote, enter the phase center of the base station antenna directly
using $PASHS,CPD,POS and setting $PASHS,ANR,OFF, or
• At the remote, enter the surveyed base station reference point using
$PASHS,CPD,POS and enter the base station antenna offset using
$PASHS,CPD,ANT, and set $PASHS,ANR,ON
Using Reference Station ID
You may monitor which reference or base station the remote receiver uses by setting
a reference station ID at the base station. For RTCM, set the reference station ID
using the command $PASHS,RTC,STI. For Ashtech DBN, use $PASHS,SIT.
For RTCM, you may also control which reference station the remote receiver uses by
setting the desired station ID at the remote receiver, or the remote receiver to use
corrections from any base station.
Reference Station Health
You may set the reference station to "unhealthy", which causes all remote receivers to
ignore the messages they receive from that base station.
Other RTCM Messages
Message 2
These are automatically generated when the base station is transmitting differential
corrections and a new ephemeris is downloaded from the satellites.