Logging Topology with simpleRTK2Blite what's needed?

Q&A forumCategory: QuestionsLogging Topology with simpleRTK2Blite what's needed?
braddo asked 2 weeks ago

Hello, newb here. I have a simple project that I think can be accomplished with an RTK2 lite but want to figure what else I need besides the kit.
My lite is on the way via DHL as we speak and I want to gather up the other stuff while I’m waiting.
My yard is not flat – there are a lot of different hills and features that I’d like to map out to aid in landscaping.
I was thinking I can create a little wheeled dolly and manually roll it around the yard and log a point cloud for the whole thing that I could later post process into a smooth 3d model…
So, I have an Android NTRIP client and a service that seems to work i.e. it streams corrections on my phone. I thought I would connect the phone to the RTK lite via bluetooth to feed the corrections and then log those results to a file.
But, … is it expected that one would plug an Xbee module into the socket and link the phone over bluetooth via that? I guess Xbee isn’t really bluetooth although maybe they make modules that speak bluetooth?
How to do logging? Is the bluetooth stream two way, i.e. will the RTK lite send the corrections back over that same link and would the NTRIP client log them?
Or do I need a different module or entirely different approach?
Thanks so much for your help!

Ardusimple Staff replied 2 weeks ago

Hi braddo,
So the lite kit comes without bluetooth. Bluetooth is sold separately: https://www.ardusimple.com/product/bluetooth-module/
How our bluetooth works: it looks like a traditional serial port under android: you send corrections to the lite, and the lite send you back RTK position that you can log.
If you are going to use another bluetooth device, just remember that the UART of the XBee socket of the lite starter kit is by default at 38400bps.

andy-parke replied 2 weeks ago

Sounds like a great project. There is a lot of technical detail to making that a reality. Once you have bought and set up the bluetooth module to receive RTK, you need to get the GNSS data out of your simpleRTK2Blite. This comes out of the TX1 pin as NMEA or uBlox messages that need to be decoded.

You could do that with an Arduino kit by connecting simpleRTK2Blite’s TX1 to the RX of the Arduino. You could use the Adafruit GPS example code and comment out the initialisation code, as simpleRTK2Blite won’t need to be initialised. Just set the Adafruit GPS code to use the default baud rate and it should work nicely.

The simplest way to log the data would be to output the desired data to the Arduino Serial port (display it in the serial monitor) then select the output (with autoscroll switched off). The setup you’d need (to wheel around) would be: (1) simpleRTK2Blite (with bluetooth adapter), (2) phone (for RTK), (3) Arduino board (connected to simpleRTK2Blite) to capture and process NMEA data, (4) laptop (connected to Arduino) to capture the processed position data. That is the simplest setup I could think of to get you started.

Good luck and enjoy!

braddo replied 2 weeks ago

Thanks for both of these replies. I was thinking I would get an Xbee3 module since it plugs into the xbee slot on the RTK lite, has an embedded microcontroller, speaks bluetooth. I *think* that should somehow give all of the ingredients needed for the above.

Not sure actually if BLE is a full fledged network protocol for XBee3 or if it’s just so you can do configuration via bluetooth with the phone. Just in case, I got a pair, so I could just use zigbee between the RTK lit and, say, my laptop if necessary.

Assuming the XB3 acts like a typical bluetooth tranceiver, anyone have tips where to learn how to, as above, capture the RTK corrections from NTRIP via the phone bluetooth, and then, pass the corrections back to something via bluetooth or zigbee?

Seems like lots of tutorial reading ahead ūüôā Wish me luck and thanks again.

B