RTCM corrections using bluethooth and 4G


I’m trying to find out If it is feasible to use two Reach devices in the following scenario:

  • One working as a base station and the other as a rover.
  • Both has a mobile phone connected by bluetooth.
  • The RTCM correction messages are sent by 4G.

In my case I don’t need a high rate location updates, but the rover should be on Fixed RTK all the time.
(to avoid waiting for convergence times)

Is it technically feasible to send the RTCM messages by 4G?
Is it possible to send the RTCM messages by Bluetooth with Reach?

Any document or information on how I can configure the devices to output/input the RTCM messages
using Bluetooth?

Thanks and regards.

No, you can not.

However, you can send your base station corrections (using TCP/IP) via 4G to a server (available for free, e.g., http://www.rtk2go.com/ ) and your rover can get the corrections (using TCP/IP) from that server via 4G. You can setup your own server if you want. Note, the Bluetooth is usually used to communicate between two devices (cell phone and REACH) and not over Internet (unless you have a program running on your cellphone which would forward the Bluetooth data to Internet).

I copied the following paragraph from the REACH documentation for you:
NTRIP is industry standard way of transferring GNSS corrections over Internet, with ReachView you can use any public service or your own private caster. NTRIP does not support point-to-point communication e.g. you can not use it to transfer corrections from one Reach to another directly. In NTRIP terminology there are servers, clients and caster. Server sends correction to a caster and clients can receive them by connecting to that caster.

Hi James,

thanks for your response, to have a process on the mobile phone that gets the information from the Bluetooth and redirects that data to a NTRIP Caster sounds feasible for me to implement.

But I’m not sure if Reach allows to output Correction messages by Bluetooth already? Does someone knows if that is implemented?

I see that when you set up the Reach as a base station you can output the corrections in different ways.


But how is supposed to access the Reach(base station) internet physically for sending NTRIP corrections?

Thanks and regards.

Hey, you can also try the TCP (see below) for direct connection over internet. The photo from REACH documentation looks different from your photo ( https://docs.emlid.com/reach/common/reachview/correction-input/ ). If you setup your REACH as a base, then it does not need to receive any corrections (unless you are trying to set it up) because it is going to generate the corrections. Anyway, it seems that REACH can receive corrections over Bluetooth (in addition to serial, NTRIP, TCP, and LoRA for REACH RS) but you need to have a program like Lefebure NTRIP Client to be running on your cellphone in order to get the NTRIP corrections from internet and send them over Bluetooth to Rover (of course, the Rover can do it itself using TCP/IP (NTRIP or TCP). It doesn’t appear that a REACH which is setup as a Base can transmit corrections via Bluetooth. I could be wrong, but even if it could, then you would need a program on your cellphone to get the corrections from Bluetooth and transmit over Internet.

Typical scenario for using TCP correction input is when both base and rover are on the same network. Note that when devices are on different networks you can not send data directly unless public IP addresses are known and routers are setup for port forwarding. TCP can also be used to send data to or receive from a remote server with public IP.

Hey thanks again for the information it is helpful.

The thing is that for the base station I don’t necessarily need to have a Bluetooth channel, it might be just connected by
wifi(as I red from the other topic NTRIP in the Field, Sending corrections from Android phone), and sorry because to use BT was an initial spec. for the base station but not really wise.

So I guess then it is a matter of doing something similar than the application that you are pointing out for connecting the Reach to the mobile phone for receiving NTRIP messages.


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