ashtech GG Surveyor, Reference Manual

Page: 97 / 256

Command/Response Formats 79
Com
m
and
s
mode. Redirection can also be bi-directional (i.e. A to B and B to A at the same time).
Table 6.7 lists the daisy chain commands and their effects.
The DSY command also works with Ports A and C, or Ports B and C in the manner
described in Table 6.7.
DTG: GLONASS Time Shift
$PASHS,DTG,f
Set GLONASS system time shift relative to GPS system time, where f is the time
shift in microseconds, from 0.0000 (default) to ±500000.0000. F is the fractional part
of the GPS-GLONASS system time offset, the integer seconds (leap seconds) and
integer hour offsets are automatically set by the receiver.
Example: Set GLONASS system time shift to -1.3 microseconds
$PASHS,DTG,-1.3
This parameter needs to be defined close to the real time shift value for the receiver to compute
position when this parameter is being used. As of September 1997, the time shift value is 1.2
microseconds.
DTM: Datum Selection
$PASHS,DTM,str
This command selects the geodetic datum used for position computation.
where str can be W84 (WGS-84), E90 (PZ-90), USR (user-defined datum), or other
predefined datum as listed in Appendix B. The default is WGS-84. Parameters for a
user-defined datum are entered with the $PASHS,UDD command on page 110.
GPS ephemeris are transmitted in WGS-84 reference system (default) and GLONASS ephemeris in
Earth-90 system (PZ-90). The positions of GLONASS satellites are automatically transformed to the
WGS-84 reference system, unless the SYS = GLO, in which case PZ-90 is used by default. If
Table 6.7: Daisy Chain Commands
Command Effect
$PASHS,DSY,A,B<Enter> Redirects A to B. Can issue from any port.
$PASHS,DSY,B,A<Enter> Redirects B to A. Can issue from any port, but it cannot be
issued from port A if $PASH,DSY,A,B<Enter> has been
sent.
$PASHS,DSY,A,OFF<Enter> Turns off redirection from A. Can issue from any port.
$PASHS,DSY,OFF<Enter> Turns off daisy chain on all ports. Can issue from any port.