How many Reach RS+ do I need?

Hello all,

I’m trying to figure out how many Reach RS+ devices do I need for some of my future survey endeavors.

I am planning to have several properties surveyed. Coordinates of the edges need to be accurate with regards to reference baseline geodetic monuments, the coordinates of which are known and set by the state.

My question is if I need one or two Reach RS+ devices to perform this task. If the task can be done with one device but there are benefits of having a second one, please let me know of those.

Thanks in advance!

Hi kbelivanis,
Based on your question I would assume that you don’t know how to use RTKlib for post processing (which I don’t either). That means you need processing software to do what you want to do. I use EZsurv and it is very nice.

Are you located in the United States?
If so how close is the closest CORS station to you?

If it is within 15km then EZsurv can post process your Survey done on that Reach RS provided that:
A. You log for at least 30 min.
B. You have no cycle break (meaning you always have good clear unobstructed sky).

I am also assuming that you don’t or wont use RTK as a solution on the one Reach RS. Some states in the US provide it free but most do not.

Hope this helps. If you are surveying only 3 properties one time, I would have to do some serious math before buying a Reach RS plus software, plus taking time to learn it all. If you provide more specifics of your project, some of the more advanced users will likely provide you some good info. But there is alot of unknowns.

Thank you timmyd.

Unfortunately although I’m located in the US, the project is located in the Balkans.

To be honest, I am willing to learn how it works, as this can prove some extra source of income if proven efficient. This is why I wouldn’t mind buying 2 Reach RS+ as long as it’s properly justified…

Just get (2) RS+. They’re cheap enough. You’ll appreciate what the BASE & ROVER can do. Especially if you are not going to use CORS but either way you’ll have the choice to or not.

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Any more insight on what it can do?

timd1971 is right. that is positively the way to go. And remember, you will need to buy some software. For non engineer folks, the free RTKLIB is near impossible to learn and it can’t easily post process the surveys that you do in the ReachView app. I’ve been there and done that.

Here is a map of CORS stations where you are heading:

I have no idea about the access to their data logs, or anything like that.

By getting two units, you can get there and create your own benchmarks on the property (letting the base ovserve for 2-4 hours and then post process with multiple cors units. Now once you have the coordinates of your “benchmark” or “known location”, you will set your base unit up over the benchmark and then survey with the rover unit in RTK mode getting corrections from your Reach RS Base. This should provide a very accurate survey. I will give you a link later today that will help alot in understanding the whole process.

You and I are both non certified surveyors and therefore we can not survey as a business. (not in the US at least). My purpose in using the Reach RS units is for drone mapping. I can no way call my work survey grade, survey quality, etc. What I can do is provide the work to a certified surveyor or engineer who can sign off on it which then makes it now certified “survey grade”. So unless you have a specific need (ie drone mapping) to use the Reach RS don’t plan on making extra money with them.

Hope this helps!

Hi @kbelivanis,

You need 2 Reach RS+ devices (ex. Reach RS+ Survey Kit).
One will be a base, another one - rover.

The workflow will be the following:

  • You’ll need to place your base over a known point, turn it on and manually insert known base coordinates in our ReachView app (app to manage the device).
  • After that, you need to turn on the rover device and set up getting corrections via LoRa radio from the base. You can use our video tutorial to do it.
  • After getting fix solution status, you’re ready to collect points with our Survey function.
  • After all, you need to export your points in the format you need.

I’d recommend you to read our docs to clarify all of the points.


Thank you timmyd for the thorough and polite response.

Truth is I don’t want the Reach RS+ for the US. I want it for France where the owner points you the edges of his/her property and then as an architect/engineer (this is what I am) I can propose construction alternatives (based on maximum heights/area coverage etc.).

I expect Reach RS+ to be useful for me, as many properties in France have not been previously surveyed, so distances and areas included in the contracts are not really accurate. I know this sounds absurd, but it is happening…

Hello Andrew,

Very short but to the point answer. So, if I understand correctly, I won’t need extra software as timmyd suggested to post-process the surveys?

Ahhh, that certainly changes my understanding :slight_smile: …one, that you can learn the RTKLIB software (because I could not but I could not be an engineer either!) And two, you will be in France not the US. It is wise to ask quetions instead of assuming :frowning:

In reply to Andrew’s response, the first step in the work flow is place the Reach Base over a known point. That means you have have a known point. If you don’t have a known point then you are going to have to create one.

This will require logging and then post processing your data to get that known point. Then the rest is very easy as Andrew has outlined.

Sounds like a good venture. And that is also a lesson learned that I can never assume someones career or lack of ability to learn this stuff. I did try to be clear that I did not know the program so as to not sound condescending. The Reach RS units are awesome!!

Good luck on your trip!

Thanks timmyd! I didn’t get offended at any point!

France has some geodetic monuments distributed (defined coordinates). To the best of my understanding, I can put my base there and then put a nail in my property and define this as my known point (in order not to have to put the base to a geodetic monument every time - and to be safe of theft).

Then each time I need to survey a property, I put my base on the nail, and go do the survey… (assuming there was no landslide or major event nearby).

Please let me know if I got it right! I am going to get the survey kit soon! I like the community a lot so far and that’s a great thing to factor in too (should be advertised!)

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Absolutely. So if you have a geodetic monuments that are within the communication range of the Reach Units, then you would do as you said.

  1. Put the Reach Base on the geodetic site, enter manual coordinates.
  2. Setup the Reach Rover with RTK from the base, and doing so establish your own known point on the property.
  3. Then once that is established, you would move the base unit over the new known point you established on the property
  4. Get busy surveying with the Rover using RTK from the on site base unit.
  5. Make some money!! :moneybag::moneybag::moneybag:

you won’t find many great communities like the one here. ; )

Hi @kbelivanis

You’ll need to post-process your logs with our version of RTKLIB if your base placed not over the known point.

So, It’ll be easier to work with geodetic points in that case.

You can also use NTRIP station as a base if there any nearby your working area in France.
It’s the same as having Reach base, so you can use only one Reach with the Internet connection (mobile hotspot or 3g/4g dongle) in that case.
Note, that NTRIP is usually quite expensive to subscribe on and recommended to be within the 8km range from its stations

Yes, you’re absolutely right :slightly_smiling_face:
I’d also recommend you to read this section about an absolute and relative position.

also, you have to have an internet connection to use a NTRIP station also. So if you’re somewhere without internet or good cellular, you would be stuck. That’s where the having (2) RS+ units comes in handy. You set them them to communicate data using LoRa (Long Range Radio). So no need for internet. But keep in mind also, you have to also meet other conditions related to the nature of GPS/GNNS work anyways…ie… good clear sky view, no major obstructions, etc etc… you’ll learn a lot reading posts here like many go through over and over at first.

My two pence worth.
You will get great results and accurate positions with the Reach units.
The positions will be delivered as very accurate latitudes and longitudes on the WGS84/ITRF2014 spheroid.

It the very least you will want to convert them to a planar projection such as UTM so they are in metres, but most probably you will quite quickly come across the requirement to deliver them in French mapping projections based on French spheroids.

Welcome to the world of historical national standards and their interplay with global systems!

Simplest solution.

Use Mapit as your data collector and set the projection before surveying. It is not perfect. It will give you a UTM position in metres east and North. So your map is flat. If you have to tie it in to the French grid you willl have to visit a French benchmark. As part of your survey and apply a correction ( simplest form an east and north shift) to your results post survey.

As you have already noted you can visit the benchmark first and transfer the datum to a local nail. This is great. It allows you to fudge the system and work on the French reference frame which will not deviate meaningfully from WGS84 over the 10km baseline.


Excuse my ignorance, but would be the difference with having 2 Reach M+ devices instead of 2 Reach RS+?

With respect to data and results: nothing.

With respect to hardware: the lack of a battery, antenna, waterproof case, and LoRa radio.

Of course you can purchase the Emlid antenna and LoRa module as accessories to the M+. Then you will still need a 5V power supply and some kind of case for it all.

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Do you not think that the RS + would have a more stable connection and longer range?

@kbelivanis, any update on your endeavor?

Did you mean that in the sense that the GNSS antenna is different? Or did you mean LoRa communication?

There might be some minor difference in satellite receiption depending on how good your M+ antenna ground plane is, but I think the RS+ and M+ LoRa modules are created equally, no?