Some informations about Reach M2 and RTK

Hi, I would like to buy two Reach M2 devices for a personal project but I have some doubts to clarify (I hope this is the right place). The two Reach M2s should be positioned on the two sides of a vehicle and should store position data that can be used together with other sensors. I read on the product page of the two modes of operation RTK and PPK. In my case, RTK would be preferable, passing the data in real-time on a Windows PC in the vehicle via the serial port. But I have some doubts about the RTK mode that I would like to clarify with you:

  1. In RTK mode there is a base station to connect the M2s to and thanks to which greater accuracy can be obtained. How do the M2s communicate with the base station and what kind of range can be achieved with the M2s in motion (maintaining centimeter accuracy)?
  2. Are the corrections on the axes that are applied to the position supplied as data (IMU) applied directly to the output data in RTK / PPK or is there a need for post production?
  3. Can I use other alternatives besides the serial port to exchange data with Windows in RTK mode? I was going to use Python
  4. If I choose to rely on an NTRIP service, is it possible to connect the M2s to the internet via smartphone or is a cellular module required for each M2?
  5. Also on the site I saw that through the Android application you can set the output of the M2, for example serial port. Is it an operation that must be repeated at every start or is the M2 able to memorize this choice?
    Thank you

They can communicate over a range of different interfaces, but most likely using an external LoRa module or over the Internet.

IMU data is not used to correct data, nor is it available without some work.

To exchange, no, but you can receive position data over a multitude of interfaces, like Bluetooth, TCP, etc.

You can do either or.

The setup is persisted, so will do the same at next setup.

1 Like

Thank you very much for the clarification. I need more information on the IMU.
One of the main purposes of my work is to correct the position provided by M2 with data from the IMU. Reading posts in the forum I did not understand if today it is possible to have these data as output or not. Could you explain to me how to do it in case? Thanks

As I have no real-life experience using the onboard IMU, I can’t offer any qualified help in this regard.
Maybe @tatiana.andreeva can elaborate a bit more?

Like Wizprod, not exchange but position data yes. You can output NMEA data via Bluetooth, TCP or serial data. The NMEA GGA string contains the quality of signal in it so you know if you are RTK float/fix or whatever accuracy.

I have used my smartphone in hotspot mode and a hotspot device to connect different data readers (Android tablet or Windows PC0

If you have availability of NTRIP with data, it will cover a much larger distance than using the LoRa radio.

Settings, for the most part are set it and forget it. The only one I have to manipulate manually is if I am returning to the same base location and need to manually enter the Lat/Lon/Alt. I use an Android copy app to copy it to a document when I initially setup the base. When I return to the location, I copy the data from the document and paste it in the manual base location.

I have not worked with IMU data, no help there either. If you are using RTK via either a base or NTRIP do you really have the need to correct the data? Depending on your baseline, your accuracy should be very tight.

2 Likes

Hi guys,

Thanks for your valuable comments!

Let me add a couple more from me :slight_smile:

At the moment, the IMU data output isn’t implemented in the software, and it’s not possible to access the IMU data.

You can transmit corrections between the receivers via LoRa radio, Internet, TCP, or Serial. But as Christian mentioned, radio and the Internet are the most popular options here.

In general, the baseline limit for multi-band devices such as Reach M2 in RTK is 60 km. But for LoRa radio, the normal operating range is 8 km in line of sight.

I’ll also leave here some guides from our docs so you can learn more about setting the Reach: