ashtech GG Surveyor, Reference Manual

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58 GG Surveyor GPS+GLONASS Reference Manual
Differential Accuracy vs. Base Data Latency
Figure 2 shows the growth of position error with increasing latency for DGPS and
DGLONASS.
RTK Accuracy and Update Rates vs. Base Data
Latency
With an RTK remote you may choose between:
1. Higher accuracy and lower update rates (Synchronized RTK)
2. Lower accuracy and higher update rates (Fast RTK)
Lower RTK accuracy still means centimeter-level accuracy
Use the command $PASHS,CPD,FST,ON/OFF to switch between the two modes.
Synchronized RTK
In this mode the remote receiver’s update rate is equal to the rate at which it receives
type 18 and 19 messages. (Maximum of 1Hz). The latency of position is
approximately equal to the latency of the base-remote data link. Typical accuracy is
Figure 5.2: DGPS and GLONASS Accuracy