Setup LR Xbees and simpleRK2B orderd as spare parts.

Q&A forumSetup LR Xbees and simpleRK2B orderd as spare parts.
paul.gu asked 4 months ago
paul.gu replied 4 months ago

First I bought one simpleRTK2B with 2 ublox antennas. It works well with Ntrip if there is good view of the sky. Now I get two LR Xbees and one more simple RTK.(I guess not preconfigured). What to change and how, I hope sombody can help.
After a lot of reading I have still a lot of questions. LR radios are bidirectional, hopfully the rover can tell which satellites he is using to get the perfect correction. I want to do private surveying, so measure the position of markstones often close to trees and sometimes even in the woods nad also in steep slopes with the sky partly coverd. For shure the base will have perfect conditions. One simpleRTK2B is not exact enough in this areas even with Ntrip correction.
Thanks for any help

Ardusimple Staff replied 4 months ago

Hi Paul,
Yes, we recommend the pre-configuration service next time so it’s plug-and-play.
– First you need to configure the UART speed at the same baudrate that you have the f9p UART2 configuration, this will allow the f9p and the xbee to communicate.
– Second you need to configure the XBee’s to talk to each other, you can find some steps in the user guide: https://www.digi.com/resources/documentation/digidocs/pdfs/90001477.pdf

4 Answers
paul.gu answered 3 months ago

Hi ardusimple staff
Thanks for the reply. I found in the Q&A the example config files and in other forums I found how to load it in my modules. It works now, in rover xbee to gps blinking in base gps to xbee. That means as far I understand unidirectional comunication. As I told in my first question the rover will never have perfect view of the sky, steep slopes and trees will partly cover the sky. I hope the accuracy would be better if the base uses only the satellites for the correction which also the rover uses at this moment. Only then have base and rover the same error and can compensate it. How can I get the info of satellites used forposition frm rover to base and tell the base to use only this satellites for calculation of the correction sent back to rover?
thanks Paul

Ardusimple Staff replied 3 months ago

Hi Paul,
All this logic is already done by u-blox module. You need to make sure the best available location to the base station.
Nevertheless if it’s of your interest, with ubx-nav-sig you can see which satellites are in use.

paul.gu answered 3 months ago

Hi, how about this: “in rover xbee to gps blinking in base gps to xbee. That means as far I understand unidirectional comunication”.Do I have to modify anything?
rgds Paul

Ardusimple Staff replied 3 months ago

That’s correct. The base is sending corrections to the rover, so the rover can calculate its position with high precision.

paul.gu answered 3 months ago

As far as I understand will I get the best precision wit bidirectional communication when the rover has not optimal view of the sky, Please lrt me know in detail what I have to do. I want that the base calculates the correction using the same satellites which the rover uses for calculation of his position,
I cannot belive that this simplertk2b is only usable in flat field with perfect view of the sky. Thanks in advance  Paul

clive1 replied 3 months ago

I doesn’t work like that. The Base doesn’t care what the Rover sees, and does very little computation. It sends a set of observations to the Rover, and the Rover gets to cherry pick what it can actually see/use. They are NOT corrections from the Base’s perspective, the Rover is solving for BOTH locations, and FIXED relationship, in that instance in time, between them.

paul.gu answered 3 months ago

Thanks, than I had a wrong information, that the base sends a simple xyz correction,