Hello, I received the Postcard last week and that’s about as long as my endeavor into GNSS/RTK has been. Complete Newbie. I have been reading up on the technology but my understanding is far from proficient and it’s been a steep learning curve.
I have updated the RTK Everywhere Firmware (version d2.2), as well as the LG290P Firmware (LG290P03AANR01A04S_BETA0212). I get the accuracy units to display on SW Maps.
I am using an iPhone with SW Maps to connect to the Postcard and utilize the NTRIP client. Once it’s all connected I can achieve RTK Float and it remains in this state. What I notice is the delta H jumps back and forth between values every half a second. For example it will say .465/.920/.465/.920/.520/.960 and on and on every half second. It does not matter how long I let it sit.
I am using the Earthscope NTRIP caster, the port: 2101 (RTCM 3.1), 2105 (BINEX), and 2110 (Processed PPP, currently unavailable). All positions are in ITRF2008.
I have it set to port 2101 in SW Maps, using NTRIP Version V1 and “Send NMEA GGA to Caster” set to on.
The Mount Point I am connected to is between 1 km to 20 km depending on where I am when trying to get the fix. SW Maps typically shows around 30 satellites fixed at any one time. Wide open sky and I have tried it in multiple locations.
I would like some advice on how to obtain an RTK Fix. I have a feeling it is the settings on the Postcard and the way it is trying to interpret the data from the NTRIP client but I cannot recognize any setting that would be helpful.
I did see there is a place to put caster details on the Postcard under the GNSS Receiver menu. It is set to the Mtpoint at Sparkfun in Colorado using rtk2go. When does this come into play? If it is set to enable, does it default to this client?
Full disclosure, I did manage to get RTK Fix for about 5 seconds earlier today but then it went right back into Float.
You can leave that Disabled since you are using SW Maps with it’s NTRIP Client.
You did a great job explaining the details, but you didn’t mention 2 things that come to mind:
Does the Rover have a clear view of the sky ? [Edit] sorry you did mention that
What Antenna are you using ?
I tried another antenna, EOS antenna ANT-L1L2L5, with the same results. I was a little over 6 kilometers from the mtpoint. After that I tried the same mtpoint but using a different caster and I was able to get a fix, so I am confident the postcard can do it. Both antennas were receiving from over 30 satellites. If that’s the case, would switching antennas really make a difference?
Once I got the fix I realized the dot turns green to signify it. When I had mentioned I got a fix in my previous post I had a blue dot, which actually means its a standard gps point. So disregard that item of information.
I will keep playing around with the postcard. Let me know if you have any thoughts or other ideas I should try.
Was that with the 5" (12cm) base plate? That’s typically the minimum size to shoot for
Ideally you’d be within 10km of the Mount Points so the signal paths at your location are sufficiently similar. As they get more sparse, having a VRS use three to get a more localized estimate might help
yes, the antenna had the base plate attached. Thank you for the explanation of why the the distance from the mtpoint is important. I kept wondering if the mtpoint data is being relayed through the phone and not over radio waves then why would it make that much difference. But it clicked when you talked about the signal paths.
