I just received my PostCard this morning.
It Worked straight out of the box after giving it some power
This Lil Guy is NO JOKE with a real antenna.
Also, the baby helical antenna performed better than I was expecting. I already have an application that justifies the baby helical.
My Data Collection Software wasnât correctly reporting the RTK Residuals, so I took a peek at the settings over Serial.
But I still have a snag. On all my SparkFun RTK Devices, I reduce the GSV messages to every 10 seconds to keep the Bluetooth pipeline clean. GSV is a bandwidth HOG.
It seems we only have 2 choices OFF, or 1
[min: 0 max: 1]
Menu: Message NMEA
1) Message RMC: 1
2) Message GGA: 1
3) Message GSV: 1
4) Message GSA: 0
5) Message VTG: 0
6) Message GLL: 0
x) Exit
3
Enter number of fixes required before GSV is reported (0 to disable) [min: 0 max: 1] (or x to exit)
We need a little more control of the NMEA Output, if possible.
Please and Thank You
Thanks! Please leave a review on the product if at all possible.
I too would like to ease the GSV traffic as I will often see >43 satellites (yowza!). Unfortunately Quectel has limited the range to what you point out: either 1 or off.
The LG290P update went fine to enable GST, and I installed todayâs RC.
I changed GSV to 0 as you mentioned with no real negative impacts, since GGA reports the # of birds.
[Edit] The RTK residuals are being reported to 0.00ft RTK, but you already explained that in the GitHub Issue #513. The PostCard is stacking points with the TOP106 antenna.
I use Surpad mainly and enabled GST after upgrading to RC from Jan 20th and also firmware v4 on the LG290P chip. And my HRMS and VRMS are blank. My PDOP is sub 1 so thatâs great but when I try to record a point Surpad tells me no (I assume because of lack of HRMS and VRMS). @rftop are you saying you atleast get 0.00 in your apps eventhough thereâs not enough precision to give the fine numbers?
My SW Maps looks like your pic. But you can still store the position, knowing the Metadata isnât correct.
In Diamond Maps, it reports : RTK Fixed 0.00â . IF the LG290P used the correct decimal places in GST, the correct value would be ~ RTK Fixed 0.03â for my particular correction source and location.
Itâs my understanding that Quectel is working on it.
The frustrating part for me is the secrecy surrounding Quectel Firmware updates.
It appears most product integrators go to the Quectel forums and beg for the FW to be emailed to them after every update. Surely there is a better distribution path for Quectel, and I just havenât stumbled upon it yet.
I agree after research and reading. Hopefully they can fix this soon because Iâm seeing way better results with this L5 antenna and this is way nicer to assemble than the um980.
We can cross our fingers. In mean time I will go observe some NGS benchmarks to compare to my facet results.
The LG290P is capable of remarkable accuracy, as is the UM980 and the F9P.
The Correction Source is the key, and obviously the antenna.
All 3 chipsets can stack points in a 3D sphere much smaller than a golf ball, repeatable over weeks (not just immediately), with proper technique, antenna, and correction source.
The exciting part to me, is the 3 chips show great agreement with each other in my testing- something I wasnât expecting.
Here in Oregon we are lucky DOT has a statewide ntrip service for free. Some surveyors have been brave enough to use it for property corners. I plan once these little issues get lined out to test a local base and rover vs the DOT network. However they say with 3 3 minute observations spread over time that you should be able to achieve 0.03 horizontal. I know with the facet I got . 14 over 880 feet between record for 2 monuments. At work we have trimble stuff but most people just put blind trust in them. So sparkfun stuff has been good to go out and test and observe what results I get.
I think thereâs a chance once they fix RMS and I build a 2nd unit I will see that my total station results vs GNSS should be within tolerance.
Iâm in Mississippi and we have a very similar free CORS network. I think ~13âish States have them.
The problem is that most of these CORS Networks are broadcasting corrections based on a Station Location from a 10-15 year-old Epoch.
To properly use the Network for any control work, we need to update each solution/position with respect to time.
You will likely find that using your DOT NTRIP corrections will seem to more closely match the NGS monumentsâ published coordinates. But once you correct the NAD83 published coordinates for time, it wont.
This is basically using the OLD position of the Reference Station (when it was commissioned) to compare the OLD published coordinates from a NGS Monument. Even if you have a perfect agreement with the RTK solution and the Monument, you still have a bogus position because the tectonic plates have been moving.
We Engineers and Surveyors love having our work tied to the Local System thatâs provided by using a state-wide CORS, but we usually donât fully understand the data source we are using.
Thatâs why I say âThe Correction Source is the keyâ to these new GNNS chips. They have the capability of providing extremely accurate results, but we cant send them garbage and expect them to be magical.
PPP is so cheap and easy now, we can basically provide accurate results without depending on work that someone else performed and hope that they maintain the Station. A control point position provided by PPP is an easy way to quickly advance beyond the absolute accuracy of a state-wide CORS, as no time shift is required. The regional PPP-RTK correction services are also very handy.
Sorry for the rambling⌠itâs an interesting topic to me, as you can tell
Maybe I need to go back and read some more out of my geodesy book but I thought the reason why our state ntrip network used NAD83 2011 epoch 2010 for a datum and either SPC for projection or we have low distortion called OCRS that calculated the positions based on that frame in time. I was going to take my todays coordinates and run them through NCAT to get back to the NAD83(91) HARN which is what most of our monuments are based on. I realize techtonic plates move and therefore those coordinates also drift but I thought that also is why we use a reference frame.
Obviously, you are way ahead of most folks.
Many times people donât know thatâs required when comparing results.
The standard lingo for RTK is â1cm+ 1ppmâ. Thatâs not necessarily the case, depending on the source of the corrections. We could easily be producing RTK solutions that are basically 15 years âoldâ, but we think we have an absolute accuracy of ~1cm + 1ppm with RTK because thatâs what the sales website claims, but with an *.
My personal opinion is that Iâd rather use ITRF, with a source that utilizes an updated reference frame and adjusted network. The positions/coordinates are true ânowâ and can be used as such. I now prefer that over a CORS Network.
I believe this works well from Control, all the way down to GIS (which is usually presented as WGS84).
All thatâs needed for Control work is the Scale Factor for Grid-to-Ground comparisons for ground truth with a total station.
I think PPP-RTK, or PPP your temporary base for Base/Rover combo is a game changer for the Industry with the inexpensive hardware thatâs available now.
My understanding is the ORGN since itâs using a RTN and has been referenced is better than the old just dial into CORS.
I want to build a second postcard now and try LoRa because as you said I know that ppk on the base point will give a more refined solution using Opus than most RTK observations.
Sparkfun equipment has made it fun to explore and dive into more of this stuff.
