Specifications

Understanding RTK/CPD 51
Understanding
4
Understanding RTK/CPD
This chapter provides CPD operation in more detail by describing CPD solution
monitoring, solution output and storage, trouble shooting and performance optimization.
RTCM reference station setup is also described briefly. The front panel setup does not
provide access to CPD rover mode, which must be configured by using serial commands
(CPD base can be set via the front panel for the Z-Surveyor and Z-Fx).
For detailed information on the commands and responses that are mentioned in this
chapter, please refer to Chapter 6, Command/Response Formats.
The following operation procedure applies to both RTCM-RTK with type 18 & 19, 20 &
21, or RTK with Ashtech DBN message.
Monitoring the CPD Rover Solution
When a receiver is set to CPD rover mode, you can monitor the current CPD solution
status and positions with the following commands:
• $PASHQ,CPD—shows the CPD setup in a tabulated format
• $PASHQ,CPD,MOD—shows the CPD setup in a $PASHR format
• $PASHQ,CPD,INF—shows the satellite information in CPD operation
• $PASHQ,CPD,STS—shows the current ambiguities fixing status
• $PASHQ,RRE—shows the post-fit carrier phase residual in CPD solution
Positions can be also monitored from GGA message or CBN message.
How to tell if the integer ambiguities are fixed?
The ambiguities fixing status can be determined through the following messages:
•STS
• GGA
•CBN
•CPD
In $PASHR,CPD,STS message. if the second field > 1.0, it means that the ambiguities are
fixed. For example,
$PASHR,CPD,STS,0.005,0124.72*5C
In $GPGGA message, a solution type of “3” in the sixth field indicates that ambiguities
are fixed.
$GPGGA,212349.00,3722.378424,N,12159.841801,W,3,08,01.0,-
00005.078,M,-032.121,M,014,*82