I have found a few other posts on this topic but my specific question wasn’t answered.

I have a number of Trimble Mapping and Geographic Informations Systems (MGIS) receivers that are capable of centimeter accuracy. I would like to know if I can replicate my workflow with an EMLID Reach RS/RS+/RS2 rover. I am a geophysicist who always needs to output NMEA 0183 messages to my instruments over a DB9 serial connection, which I can do with the Reach units.

With my Trimble Geo7x receiver I collect data with either SBAS or RTCM VRS real time corrections when I am within cell coverage. When I finish my surveys I download the data and post process it in Trimble GPS Pathfinder Office. I would like to have the ability to utilize SBAS corrections for real time accuracy that should be on the order of 50 cm.

I regularly work in areas with no cellular coverage. Is it possible to use SBAS corrections with EMLID rovers and then post process my data? This would be the most important feature for me. This would give me all of the options that I need to be able to do RTK, PPK, and some options in between.

Reach does not currenty employ SBAS correction in the live position solution. Reach does record the SBAS data in its raw log. So you can use post-processing software to compute an SBAS-corrected position solution. You should be able to select the output file format as NMEA 0183 if that is what you want.

If you are within a cell coverage area and RTCM corrections are available, then you can output a corrected RTK position solution live in NMEA 0183 format.

I realize that reach doesn’t currently have an option to utilize the SBAS corrections. I would like to know if there is a way to have it implemented.

I understand how GNSS systems work. I have used every grade of Trimble receiver for 20 years and am quite proficient with PPK, RTK, VRS, RTCM, RTX, SBAS, OPUS, and UNAVCO TECQ processing.

The Reach RS2 units would be perfect for me if there was a way to use SBAS corrections in real time. That way I as the end user could choose what type of correction to use based on my current needs. Many times SBAS corrections in real time, which can be better than 50 cm, are more than sufficient for my current task. I can always choose to post process the data later if I want to, but I may not. The uncorrected positions are not sufficient for any of my applications.

So to restate my question. Is it possible to set up the Reach units so that they use SBAS corrections as a real time correction.


If you familiarize yourself with Linux and RTKLIB, then yes I think you can get some live SBAS-corrected output from Reach. It is a matter of changing the RTKLIB command-line options/config files to make it work. You may no longer have the benefit of the ReachView GUI though, depending on how you approach it.

If you don’t need live output, then anyone can take the raw data files and post-process them with SBAS-corrections. You can use the RTKLIB post-processing software.

I am speaking about Reach M+ and Reach RS+ as they have the same GNSS chip.

RS2 isn’t released yet (soon!) and it uses a different GNSS chip. So I am not aware of any infomation about the multi-frequency RS2 operating as a non-RTK, SBAS-corrected receiver. You might be the first to try it if you do.

One approach might be to ask for an example data set, then download the RTKLIB software and post-process it yourself. Once you are comfortable with that, you could purchase a Reach device and try implementing the same config options in the live processing.

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That worked for me :smiley:

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Hey there,

At the moment, Reach RS2 doesn’t work with SBAS constellations at all. It can use them neither for getting corrections nor for calculating RTK solution.

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I’m not sure what you are suggesting. I purchased two of the original EMLID Reach development boards when they were first released. I then purchased two Reach RS units when they were released. I have collected RTK and PPK data with them. I have not found a way to have SBAS corrections applied in real time.

I understand that the capability does not currently exist. My question is if it is possible? My understanding is that the board used in the new Reach RS2 units does natively support SBAS corrections in real time. Will this capability be supported in the RS2?

I am familiar with Linux as I have been using it since I did my MS 20+ years ago. There is no point in post processing Reach files to utilize the SBAS data, it is only relevant for real-time applications. On the post processing side there would almost always be a much more accurate CORS RINEX file available. This discussion is specifically about real time SBAS corrections on Reach.

Older Trimble Mapping and GIS (MGIS) instruments such as the GeoXH 6000 which was dual frequency GPS and GLONASS would discard the GLONASS data when using SBAS for real time GPS corrections. Newer Trimble MGIS instruments such as the Geo7x will make a blended solution of GPS corrected in real time with the GLONASS solution for much more accurate real time solutions. All of these instruments could also use RTCM corrections as an option as well as saving the data for later post processing.

I want the ability to choose from multiple real time solutions (uncorrected, SBAS corrected, RTCM corrected, RTK corrected) based on my current need while still being able to post process.

If you had the original Reach GNSS modules, then you had ReachView version 0.x.x installed. Back in those days there were settings in ReachView that would allow you to do live SBAS-corrected positioning. Since ReachView 2, there has been no support for SBAS-corrected positioning in the user-interface.

I will maintain that the hardware can do it, but only if you make it happen yourself.

It is not something you can do in an ‘app’, so you will have to start here:


The reply pertains to all the Reach products, except RS2. I know the RS2 hardware receives the SBAS signals, but that is all I know about it. My hunch is that you’d be better off in the persuit of SBAS corrections with your original Reach modules or Reach RS.

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Hi @ryanenorth,

We don’t have plans on SBAS real-time corrections support.

Ryan, geo here too so I’m also interested in this. I assume you are US based but here in Europe there is the EDAS service which provides EGNOS corrections over the internet ( Perhaps there is something similar for WAAS?

I’m still following up on this since it has been two months. I really would like this feature and the board inside the Reach RS2 supports it. Is there any way to request it?

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EGNOS corrections are broadcast over most of Europe and are the equivalent of WAAS in the USA. Both of these are considered Space Based Augmentation Systems (SBAS) and are broadcast on the same frequencies as the GPS data so pretty much any receiver can get them. One of the past issues in the USA was that many receivers that were multiconstellation would stop using any constellation except for GPS when they received the WAAS corrections. Trimble introduced the capability to calculate a merged solution of the GPS/WAAS with the other constellations when they released the Geo7x unit. This capability led to real time accuracies of less than 50 cm most of the time, with the ability to post-process the data for higher accuracy.

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If I had internet access, I would just use RTCM streamed corrections from a CORS which would be much better than the SBAS corrections.

Hi Ryan,

Thanks for your request, it’s noted. However, we currently don’t have plans on adding SBAS support for real-time survey:

I get you! I use it occassionally with an old trimble receiver which doesn’t get SBAS corrections anymore due to old firmware so it’s useful for that situation since I don’t have access to a free CORS service. It means I can get a little more accuracy from an old piece of kit without needing to pay for a service or set up a base.