So I got this module (twice) which gives 1 serial device when connected via USB (I haven’t connected the other UARTs of it), and I’m trying through this single connection to get an RTK fix by using one of the modules in rover mode with PQTMCFGRCVRMODE,W,1 and the other with as base with PQTMCFGRCVRMODE,W,2 and those seem to activate and work correctly after a save and reset since I see on QGNSS that the rover outputs NMEA and the base outputs RTCM.
However I made a little python program that sends the raw binary data of RTCM as they are captured with pyrtcm module from the base to the rover (I threading.Lock the reading and writing every time to keep the connection stable) but I see neither a float or a fix in the GNGGA output of the rover and on QGNSS I don’t have much luck either and if I use the rools of rtklib to try to do it without hardware: for some reason the RTCM data of the base do not produce a fix even in single mode but it only captures the satellites without ever getting a fix as if some data missing.
So I wonder do I have to do anything else from the default settings of the modules other than turning them to rover or base mode and then saving and then resetting/rebooting. It’s very suspicious that the RTCM data of the base I get don’t get a fix even with an external program like rtklib in single-mode while that program does see the satellites so my best bet is that I just don’t get all the data from the base and I’m missing some settings but I don’t know what that is since I have definitely tried 1005 and MSM 4 or MSM 7 (and the coordinates have been set either with a $PQTMCFGSVIN,W,1,300,0,0,0,0*21 or a $PQTMCFGSVIN,W,2,0,[...] though I think the first one couldn’t get a fix either (so I guess a basic question is “what are the minimum settings that I need for the base or any other mode to get RTCM output and that RTCM output to be enough at least for a single-mode fix?”).
@epigramx ,I can tell you that just resetting the LG290P in Rover or Base mode with default settings is sufficient for them to work and achieve RTK Fix.
I would try your Rover and Base configuration one at a time with QGNSS first to verify proper operation first.
For Rover mode, connect to QGNSS and set up the NTRIP client (hopefully you have access to a NTRIP server) and see if you can achive RTK fix.
For the Base mode, connect to QGNSS as well but this time set up the NTRIP Server to a free public caster like rtk2go.com, caster.centipede.fr, or rtknavi.com. Then test it with a NTRIP client. That way, you can independently very the Rover and Base operation.
Doesn’t it also need a Survey-in setting, if it’s going to be used only after the two are reset? Today I managed to get a Float so I’m getting there (it would be obviously a fix both weren’t almost under a roof) but I’m trying to find the most efficient way to do it (preferably with using only a single python program piping between the two serial ports).
You would think so, but when I did the basic Base default, which disables Survey-in, the caster still reports a base station location, so it’s getting that from somewhere…But yes, you should probably set the Survey-in mode you want, but not doing it doesn’t seem to stop it from working, albeit with a less accurate Base station location…
What are you trying to achieve? A single computer Rover and Base station solution? How would that be used? Typically the Base is fixed and the Rover moves and the RTK corrections are transmitted to the rover via radio or Internet.
Just a regular surveying setup of a static base (and maybe a third module as a mobile base). I currently try avoid using any complex server-client stuff because it’s theoretically possible to pipe everything inside the same application.
Still a bit confused about what data are required for rtk or what data are not required by they help for solutions (apart from base coords).
So you have the Base station at a known position, for which you want to input the fixed Survey-in posiiton, and then have the Rover find it’s accurate position based on the RTK correction information from that known base? Ok, but if both the Base and the Rover are connected serially to the same computer, how far apart can they be? Most systems like this utilize radio links or the Internet to link the Base and Rover together.
I’m no GNSS expert, but based on what the LG290P transmits in default mode, it seems that all you need are the following RTCM messages from the Base module in order for the Rover to achieve RTK Fix:
RTCM 1005 - RTK Base station location - by default, if survey-in is disabled, it still sends it’s current location. Obviously, if you want an accurate location, then you should input the fixed ECEF location for it to transmit.
By default, the LG290P in Base station mode transmits MSM4 messages.
Using the computer to feed RTK serial information from the Base to the serial port of the Rover SHOULD allow it to achieve RTK fix. The default mode of the serial ports is to accept both NMEA and RTCM protocols on all the ports so if you were using python to pipe the RTCM messages from the base to the rover port, you should be able to achieve RTK Fix, even though there are close together…
Oh yeah I’m not doing plain serial connections on the complete solution in the future (it’s only for testing on a PC for now for developing the software (I’ll use internet and radio connections later)).
I noticed that if I use no survey-in settings the location of 1005 may fluctuate per second; for testing I’m using an approximate location with the fixed option of the survey-in method; that is steady.
So I managed to get an RTK fix now; that was under a balcony; that’s seeing less than half of the sky; I was expecting it to fix faster (in less than 4min) but I guess that was too optimistic.
PS sorry for being late replying to you but the forum forced a 10 hour delay due to new account
It must use it’s regular 3D location for 1005 when survey-in is not set up. I’ve used the fixed survey-in mode before but haven’t tried the survey mode where it averages the position. In practice, my base station software can send a fixed 1005 location so I disable 1005 from the module.
What survey software are you planning on using? Many people, including myself, use the SW Maps app. It works well, is free, and does what I need, which is not real surveying, but just marking and measuring positions.