Specifications

Differential and RTK Operations 31
Differential and RTK
The receiver also transmits a BPS message (base position) every 30 seconds by
default (the periodicity can be set with the $PASHS,CPD,PEB command).
DBN messages are shorter than their RTCM equivalent, so they provide lower latency. If the data
link is not very reliable, use RTCM messages because they can be used partially, unlike DBN
messages, so in that configuration, the chances of obtaining a reasonable position solution are higher
with RTCM than with DBN.
Setting Up a Combined Differential and RTK Base
Station
You must have both the [B] and [K] installed in your receiver.
Send the commands listed in Table 3.5 to the receiver.
Type 1 is on continuously by default.
The receiver is set as a base station which transmits RTCM Differential corrections
(type 1) every second, RTCM messages types 18 and 19 every second, and types 3
Table 3.5: Base Station Commands
Command Description
$PASHS,RST Reset the receiver to factory defaults
$PASHS,PEM,4 Set the Base differential mask to four
degrees
$PASHS,ELM,9 Set the RTK base elevation mask to nine
degrees
$PASHS,POS,ddmm.mmm,d,dddmm.mmm,d,saaaaa.aa Enter the phase center of the antenna if ANR
is OFF or the ground mark if ANR is ON.
Do not set ANR to CPD in this case.
$PASHS,RTC,BAS,x Turn on RTCM corrections on port x
$PASHS,RTC,SPD,9 Set internal bit-rate for corrections to burst
mode
$PASHS,RTC,TYP,1,1
$PASHS,RTC,TYP,3,1
$PASHS,RTC,TYP,22,1
Turn on type 1 message differential
correction message once per second
Turn on base station position messages 3 &
22 once per minute
$PASHS,RTC,TYP,18,1 Turn on Code and Carrier phase messages,
once per second
$PASHS,SAV,Y Save settings