Vdp: Vdop Mask - ashtech DG16 Reference Manual

If processing raw data from the receiver with your own processing algorithms, enable UTS.
$PASHQ,UTS,[c1]
The associated query command is $PASHQ,UTS,[c1], where c1 is the optional
output port. If a port is not specified, the receiver sends the response to the current
port.
$PASHQ,UTS,
The response message is in the format:
$PASHR,UTS,x*cc
where x is ON or OFF and *cc is the checksum.

VDP: VDOP Mask

$PASHS,VDP,d1
This command sets the value of the VDOP mask, where d1 is a number between
0 and 99. If the VDOP value computed by the DG16 is higher than the VDOP mask
value, the receiver will automatically go into fixed altitude mode. You can view the
current VDOP mask value by entering the query command $PASHQ,PAR and
checking the VDP field.
Example
Enter the following command to the set the VDOP mask value to 6:
$PASHS,VDP,6
VIS: Satellite Visibility
$PASHQ,VIS,[c1]
This command queries the satellites currently visible in the sky, where c1 is the
optional output port. If a port is not specified, the receiver sends the response to
the current port.
180
DEFAULT SETTING
UTS—OFF
DEFAULT SETTING
VDP—4
DG14 and DG16 Board & Sensor Reference Manual