Providing emlid M2 with internet via Modem on Ubuntu

Hi everyone,
I am currently using the emlid M2 on a Ubuntu 20.04 OS to get NTRIP corrections. I have no issues with providing M2 with an internet connection via a hotspot from a mobile phone or even the PC (Ubuntu) itself. For the next step I do wish to go a bit further and provide the device with internet from an LTE modem ( AirPrime EM7455
Until now I am sure, that the internet connection via modem works fine and the corrections are received over the modem’s hotspot. But I would like to get the connection between the M2(with UBS connected to the PC) and the modem in order to avoid latency due to connection between M2-modem-PC(robot). In my research I came across “bridge” connections. That has failed, because I can connect the M2 to the bridge, but the connection from the modem (gsm) to the bridge fails.
Is there something that I am forgetting to take into consideration? Is my setup wrong or is there an easier way to achieve this goal?
This is my first post and I hope I could describe my issue so that it is understandable.
I would be very happy for a solution! :slight_smile:

Hi @donaldduck2224,

Welcome to the forum!

Just to confirm, you would like to provide Reach M2 with Internet access via a direct USB-to-PC connection, correct? If so, this feature is currently not available on our Reach module. I will add your request as +1 to our internal feature request list.

Hi @olesia.riman ,

and thank you very much for your quick answer!
Yes, you have understood me correctly. Surveying outdoors, the robot will have an internet connection over a modem and should preferabily provide the M2 with internet direktly and not over a hotspot. The M2 device will also be connected to the robot via USB.
Looking at this link from the emlid documentation page, I was wundering if the wished setup could be achieved by connecting an extra modem to the USB port of M2 (like this) and at the same time providing the device with power over the JST-GH port using a GPS-UART to USB Converter(similar to this? This idea is in my eyes just a workaround the issue above and I am not quiet sure if it makes a difference at all. In the end it could be that M2 would not be able to connect to it anyways.


We haven’t tested GPS-UART to USB Converter ourselves, but the idea looks okay overall. From the M2 side, the setup with an LTE modem connected to the receiver and powered by JST-GH should work fine.

However, please make sure your power supply meets Reach M2 requirements. The power supply voltage on Reach M2 JST-GH port should be in the 4.75 - 5.5 V range.

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@donaldduck2224 I suggest that there is more than one way to accomplish what you want to do.

One of the ways that works is to power M2 with the JST-GH connector, then plug in a USB-to-Ethernet adapter (you may need a USB-OTG adapter for this.
(the TRENDnet TU2-ETG is one that is verified as working with latest. currently v31.8).

Connect M2 to your robot computer with an Ethernet cable.

Then, on Ubuntu 20.04 you will have to figure out how to install and run a DHCP server on the ethernet port
(e.g. dnsmasq running on interface: eth0)

And also set up NAT firewall rules to forward the packets coming from the M2 out to the USB/cellular-modem and to the Internet.

Alternatively, if you want to pay for assistance or to discuss other options, you could contact me directly.


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