Hemisphere GPS
RTK Rover Workflow for Crescent Based Receivers p/n 874-0004-000
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$>JAPP,LOCRTK,AUTODIFF,1,2
The important item is that
LOCRTK
appears immediately after
$JAPP
. If the word
LOCRTK
is in the text but not as the first application (see below), you will have to switch
applications inside the receiver:
$>JAPP,AUTODIFF,LOCRTK,2,1
To switch applications, issue
$JAPP,OTHER
to the receiver and it will reboot in the new
application. You may need to reconnect your PC software once this happens.
If the
LOCRTK
application is not installed on the receiver, you will have to do that before
you can have it work as an RTK rover. Consult your dealer or Hemisphere GNSS
Technical Support for more details.
7.
Once you have confirmed the
LOCRTK
application is active, issue a
$JK
command to
ensure the subscription code is ready to work as an RTK rover. The response will be
something like this:
$>JK,01/01/3004,04
The number
3004
here is important. This is the subscription code. If the code is
3004
,
3005
,
3008
, or
3009
, the receiver will be able to work as an RTK rover. If the number is
not one of these two values, contact your dealer or Hemisphere GNSS Technical
Support. They will need to have all of the information from the response to the
$JI
command. For example:
$>JI,1800072,1,7,30062008,01/01/1900,01/01/3000,1.5L,46
8.
Once you have confirmed that the subscription code is capable of working as an RTK
rover, you are ready to start receiving corrections on one of the ports. This workflow will
use Port B for receiving corrections.
9.
Ensure your corrections port is set to the correct baud rate. You can use
$JSHOW
to
verify what it is currently set to, or you can just re-define it as needed. For example,
assuming you are connected to Port A through your software, issue
$JBAUD,9600,OTHER
to set Port B to 9600 baud.
10.
Typically corrections are transmitted over a radio modem link from the base to the rover.
Ensure the rover radio modem device is set to the correct baud rate and is ready to
receive corrections. Ensure the radio antenna is connected properly and is located in an
appropriate location. Apply power to the radio modem. Connect the radio modem data
port to the GPS receiver
ʼ
s correction port (Port B for this workflow).
11.
The RTK corrections are in a certain format. The receiver accepts DFX correction
formats. Use DFX format (Hemisphere GNSS proprietary) for the highest performance
of your RTK system – it is best suited for use with all Hemisphere GNSS equipment.
The Crescent RTK rover will automatically sense which correction format is being
received and will start functioning as an RTK rover.
12.
You can issue the
$JASC,GPGGA,1
and
$JASC,GPGST,1
commands to watch the
performance and accuracy of the RTK rover.
