SparkFun LG290P Quadband GNSS RTK
I’ve been messing with GPS modules for a while now. I’m always on the hunt for the best bang for the buck or the best learning tool. I recently stumbled across the Sparkfun LG290P Real Time Kinematic (RTK) GNSS board.
RTK has the ability to geo locate you to within 1 CENTIMETER of your location. Most GNSS modules net you about a 3 meter tolerance.
That is crazy accurate. Many of these RTK engines cost big $$$. This module is based on the Quectel LG290P engine. The good news is that it is lighter, cheaper, and runs cooler than most other RTK modules. Sparkfun sets the cost at $189 which is amazing.
Software – Quectel QGNSS
In order to set this bad boy up you need to download a Windows only program called QGNSS. As I write this the current version is 2.4 and you need to create a login with Quectel to get at the download button. Once you open the program and get it running it looks like this:
The default baud rate for the COM port it lands on is 460800 and it appears as an “Enhanced COM Port” in the Windows Device Manager.
Quadband
The receiver tracks the following systems: GPS, GLONASS, Galileo, BDS, QZSS, and NavIC GNSS. It also supports SBAS augmentation systems (WAAS, EGNOS, BDSBAS, MSAS, GAGAN, and SDCM), PPP services* (BDS PPP-B2b, QZSS CLAS, MADOCA-PPP, and Galileo HAS), RTCM, and RTK.
It also covers L1, L2, L5 and E6 frequencies. So by my estimation this is a very capable receiver with tons of capabilities for not a lot of money.
Firmware
After playing with the module for a while I realized it needed a firmware update. The shipped version was FW:LG290P03AANR01A055. The update was found here and was version FW:LG290P03AANR02A01S. The Quectel instructions and Sparkfun instructions were pretty different. A lot different. In fact I tried following the instructions and it kept failing. Maybe tried it 10 times. I wish I remembered what I did to make it work but it eventually started loading and took successfully. The update process took maybe a minute or so once it got started.
I think you have to have it on enhanced COM port A and set the baud rate to 460800. Then at the top where it says “Settings” that is a drop down box that allows you to reset the module. Reset and then push the icon labelled 1 which reboots the board and then push 2 (quickly) to begin the process.
Software QGNSS Bugs
Everything seems to be working okay but the OpenStreetMap depiction shows a 403r error on each map tile which means the headers are not being sent correctly to the OpenStreetMap server according to Dr. Google. I emailed their Support department and am waiting to see if and how they respond. Not a big deal but hey, I’d like it to work.
Sparkfun LG290P RTK
So far I have not gotten an RTK lock, however, my antenna is indoors and is likely tuned for an L1 and maybe L2 device. I have not yet taken it outdoors and I might have to pick up another antenna with L5 capabilities. I have no doubts though that RTK will work as advertised once given the correct setup.
My Conclusions
The Sparkfun LG290P breakout board with the Quectel chipset is an amazing bargain. The software isn’t as polished as U-blox’s u-center or u-center2 software but it works. The issue with the blocked map tiles is a bit perplexing but I’m pretty sure I’ll get a resolution. I tried to download a previous version of QGNSS but couldn’t find an archive anywhere.
For the price you pay, you get a Quadband receiver that covers darn near all the GNSS goodies with the icing on the cake being 1 centimeter of accuracy. Also the refresh rate defaults to 10Hz which is pretty quick. You can bump it up from there if you need as well.
I don’t really see anything else touching the capabilities of this at this price point. If you want to get into RTK positioning, this is your Huckleberry.