Picked up a new RS2 to use as a base with my RS+

[Cowboys703 (Tthrailkill)]

I go into Base mode on my RS2 (following the guide) and in the list of RTCM3 messages, none of the satellite systems match what is on my RS+ (or for that matter what the guide says). THe only one that matches is the ARP Station coordinates

All others:

GPS L1 on the guide/RS+: Not on RS2
Glonass L1: Not on RS2
Galileo MSM7: is listed as MSM4 on RS2…

There are many examples of this. I was told that the RS2 would work as a base for RS+. I’m getting mostly 10 to 15 cm accuracy with brief flashes to less than a cm accuracy

[michaelL (Michael Lambert)]

Ideally you want a pair of RS2’s but if you are going to mix I would set the RS+ as the base. The RS2 is newer tech and a little more robust as a rover but either way you are only going to get L1 corrections.

[Cowboys703 (Tthrailkill)]

So are you saying that there was literally no reason for me to get an RS2 (instead of a second RS+) since I already had an RS+?

I’m trying to get good field readings in sites with lots of tree cover and I figured the RS2 would be the better option to send corrections since it has the stronger antenna and what not. There’s some sites where I have zero cell phone reception, I’m 100 miles from a base station or don’t have a clear line of site throughout the whole site.

I’m getting pretty frustrated with this thing. If I walk 20 meters away from the base I have to wait 10 minutes to get back to under 20cm of “accuracy”

[michaelL (Michael Lambert)]

I mean you’re half way to an RS2 setup… Or maybe check out some of the M2 setups here in the forum and sell your RS+'s.

[EBE111057 (Bryan Enfinger)]

If you use the RS+ as a base, the RS2 rover will only receive corrections of L1 from the RS+ (L1 data only).

Same with the RS2 as base. The RS+ will only receive L1 data. The combo will work together but you are losing the advantages of dual (L1/L2) frequencies. This has been discussed before on the forum.

[polina.buriak]

Hi @Cowboys703,

Thanks for reaching out to us! Better be out with what frustrates you.

I can see our users have already described the main pros and cons of your setup. I’ll just be making the comments on some points. Sorry if I have to repeat what’s been already said.

Generally, what you have now is a system that works as a single-band one, even though you have Reach RS2. This happens because your rover is Reach RS+, and it doesn’t have any multi-band advantages. It works with L1 signal.

I would also contradict @michaelL and urge you not to make RS+ a base in such setup. If you’re mixing the single-band and multi-band systems, the multi-band should be the base. Otherwise, RS2 has trouble understanding the L1-messages and may not even get the Float solution.

@Cowboys703

in the list of RTCM3 messages, none of the satellite systems match what is on my RS+

The messages are indeed different, that’s true. The reason for this is that we list the messages needed to work with another multi-band system. Reach RS+ is a single-band receiver. It can work with the same messages but it gets the L1 part of them.

@Cowboys703

I’m trying to get good field readings in sites with lots of tree cover and I figured the RS2 would be the better option to send corrections since it has the stronger antenna and what not.

Reach RS2 is a better option. But the main point here is that the whole RTK system (as in, base and rover) should be multi-band to get the use of this better option. In your case, it’s not.

Still, if you manage to get the mobile data coverage in your area, you can use Reach RS2 with a SIM and NTRIP service. This way, you’ll get all benefits: a more robust solution in somewhat difficult conditions, longer baselines, and shorter time for the first Fix.

@Cowboys703

I’m getting mostly 10 to 15 cm accuracy with brief flashes to less than a cm accuracy

From what I get, you’re surveying in rather harsh conditions for RS+. This means that the data quality on the rover is somewhat reduced. This affects the solution, of course.

Also, if you’re using LoRa to transmit the corrections, please make sure you have a line of sight and no obstacles. If that’s not possible, you might want to consider another way to transmit corrections (like external radios or NTRIP caster).

If you don’t have access to NTRIP services on-site to work with Reach RS2, I can see two ways of getting the cm-accuracy here:

• upgrading your RTK setup to be fully multi-band (as Michael mentioned, Reach M2 may be a more budget investment)
• using the non-GNSS solution for your environment

Just a quick reminder that dense forest and almost full sky coverage may be too harsh even for the multi-band receivers. Such environmental conditions ask for non-satellite-based ways to get the position there.

[Cowboys703 (Tthrailkill)]

Ok, so the dual band stuff makes sense. I’m not sure how I missed out on that and I was possibly mislead by the dealer when I asked him about RS+/RS2 compatibility (he also probably just misunderstood me).

We’re a pretty small company so getting another RS2 anytime soon is unlikely. I don’t know how an M2 setup would help me as we don’t have a drone that it is likely to fit on and I don’t need aerial images of my sites, I need specific elevation and location data points.

The site I’m going to today is a pretty harsh site but isn’t too typical of our sites. It’s mostly old citrus groves and new developments out in the boonies. I was really hoping this would provide decent results all over the sites but I guess I also missed needing the line of sight for the LoRa.

How well would this setup work with manually entered fixed points? We’re looking to get some benchmarks installed at our mitigation bank for future construction activities. This is a very forested area with several large clearings. The hope was to set up a base station in the clearings and use that to relay the corrections to the areas close to trees and obstructions.

[michaelL (Michael Lambert)]

@Cowboys703

I don’t know how an M2 setup would help me

Just search the forum for M2 rover or M2 base. It is fairly easy to make some kind of enclosure and mount the antenna in such a way that it will function just like an RS2. Keeping in mind that the M2 would need an external power source like a 5v power bank. Here’s an example of what @EBE111057 did. He has another post with more detail but I haven’t found it.

Wrong false fake fix Emlid m2

Here’s a couple of pics. You can buy the 5/8"x 11 adapter at most survey supply stores. The female end simply screws into the bipod or adapter on a tribrachs. I just bought a nut at a local hardware store for the male end which is inside the cap. The other hole is for the antenna cable out to the M2. I don’t keep anything in the PVC mount, it’s just for the helical antenna. I’d like to make it bigger for the battery, M2 and LoRa; but I no longer use the helical antenna. The Harxon GPS 500…

[EBE111057 (Bryan Enfinger)]

Yep, the M2’s are great little receivers for static use. They cost about $500 but you’ll also need a good NGS calibrated antenna. Harxons have a lot of antenna’s to select. You can get a good antenna for about $300 or less. Just make sure the antenna meets the voltage specs for the M2.

I’ve only accessed the state RTN service once with it… got fix within about 5 sec. I was just playing around with it with a hotspot from my phone. From my experience, high multi-path areas like yours will be a challenge to obtain a reliable fix with RTN or RTK. You’ll probably have to have at least a 1 hour observation on each point. It’ll be noisy data, but a good commercial PP software should give a reliable fix solution if there’s enough data.

[michaelL (Michael Lambert)]

Do you think an M2 would make a decent base?

[Gabriel_C (GCG)]

@Cowboys703

I don’t know how an M2 setup would help me as we don’t have a drone that it is likely to fit on and I don’t need aerial images of my sites, I need specific elevation and location data points.

You can see pictures of a bare bones version of a static setup with an M2 that I have used in this topic.

It’s about USD 800$ for the receiver, an antenna, and power bank. Throw in a little extra for a lora module and you can work with an RS2 seamlessly for under 1000$.

[wizprod (Christian Grüner)]

@michaelL

Do you think an M2 would make a decent base?

I can confirm it will! I have unit in the shed that has been running uninterrupted for for almost 2 months now. Extremely stable little thing!

[polina.buriak]

Hi @Cowboys703,

I get you. This is not an obvious thing. Let’s try to get around it somehow.

I see that your planned surveying sites are pretty harsh. Very forested areas are too hard for any GNSS receivers. Usually, it’s a long way to get even a sub-cm accuracy. You might indeed think of additional, non-satellites-based solutions.

You can, of course, go with the Reach M2 option. Though not initially designed for the ground surveying, it can work just fine. Still, you will need to create a setup that works best for you. You can take inspiration from the installations our users shared. Couple of threads to take a look at:

• Mark’s build
• Brian’s build
• jp-drain-sol’s build
• Nykodym’s build

This is just a small portion of all solution you can come across. Such placements make it possible to survey the separate points with the receiver. Of course, all of this requires getting hands-on with it.

Also, the transfer of corrections is of great importance. Heavily covered area means there are a lot of obstacles between the base and rover receivers. To eliminate them, you can:

• use more powerful radios on both your base and rover
• use Internet connection, if it’s possible

With RS2 + RS+ and LoRa, Fix solution in forestry area is a bit of a wild expectation. If you can work with the sub-meter accuracy, though, this is something you can achieve.