What settings for a fix?

Hi guys,

I am pretty new to Emlid Reach, RTK, etc. Let me expose to you the setup I am working with :
-One of the Reach modules + GPS antennas are on tripod and serve as the base. That’s static.
-The other pair Reach module/GPS antenna is on a drone and this is obviously the rover. Right now it’s not flying, I just move it around by carrying it.

Note that I haven’t set up APM Mission Planner or the Reach modules to be used as a GPS system by the drone. I am trying to minimize the sources of errors right now so I will do this later. I basically followed the Quickstart guide to configure the Reach modules.

Both Reach modules communicate on a local network through a router. This router is not connected to the Internet since I am carrying out experiments outside. But I updated Reachview to the latest version beforehand. Both GPS antennas are also mounted on ground planes.

Now let me tell you about my routine when I deploy the whole thing outside. I deploy the base and the rover 50 meters apart in a field. They both have an unobstructed view of the skies. I locate and update the coordinates of the base. Then I pray for getting a fix.

So far I have gotten a fix twice, on two different days. Both days had great weather with blue cloudless skies. I was getting 10/12 satellites with 5 or more having a green gauge. The fixes were held for a few minutes, then they disappeared and I never got them again for more than a few seconds both days. I have never obtained a fix with the stock settings. I have been trying to mess with some settings after searching some threads on the forum here, of guys trying to find the right tweaks to get a fix reliably. Unfortunately, this seems to be randomly occurring for me which is why I want to seek advice from you guys :

what settings do you use, tweak, not touch to get a reliable fix ?
Are there some common mistakes/pitfalls to avoid when trying to get a fix ?
Is there a tutorial on how to use/post process logs to understand what’s happening and what could be the problem ?

I am attaching a link for the logs of today’s experiment when I got a fix from around 20:34 until 20:37.


Sorry if this topic is repetitive and thank you for your help !



Which antennas are you using and if the patch antennas that come with the Reach kit, are you using ground planes underneath them?

@savvy0816 Yep, he has ground planes.

@simon.tp.duthoit Without looking at your log files, you say that you have 5 satellites with signal strength in the green range. Are these 5 green satellites all from GPS constellation? No? If they are a mix of constellations , such as GPS and Glonass, then you may need to look for 5 green GPS satellites.

Could you elaborate on the constellation ? How do you determine that ? And how can you determine which one would be the best to choose ?

By the way I am using the Talysman antennas that come with the whole kit.

By constellation, I meant one of: GPS, Glonass, Beidou, etc.

I am usually looking for 5 or 6 green GPS satellites before I expect a fix. They would be named: Gxx, or 1xx. (Glonass would be Rxx)

Hi Simon,

By looking through your log folder I can see that you use old Reach View. Try our new beta :slight_smile:

Also, I can say that in the rover log are not so many satellites that could also be the reason of such result.


thanks for your answer first of all !

According to you how many satellites should I get, and how many in green ? This is really strange because I am in a clear field without obstructions and with clear skies ! Maybe the Talysman antennas are not performant enough ?

Other question for you, how did you manage to visualize this from the logs ? With a software from RTK lib ?

Thanks !

Thanks !

What drives the choice of the GPS constellation for you (and the frequency) ?

I am at a middle-northern latitude and the GPS constellation is very good here. The frequency for RTK that I have been using lately is 10Hz.


And do you use any particular settings that are different from the stock ones ? What about the GPS antennas, do you use the Talysman ones ?

Lately, I have only been post-processing with the raw logs, so I haven’t been changing the settings from stock except for 10Hz frequency.

I was using the provided Tallysman antennas which were fine, and then moved to the TW3710 which seem good, but I have not done a side-by-side test yet. Maybe soon.


Thank you for your help.

I hope someone can help me with trying to get a more reliable fix !

The more the better :wink:
But 5 is not too much, you need 4 minimum to get position in 3-dimensions.

Could you show a picture of your setup?

You could visualize your solution logs in RTKLIB RTKPLOT or post-process you raw data first as it written in our docs.


You should see pictures of both antennas mounted on the tripod (base) and the drone (rover). You’ll notice another GPS antenna on the drone but it is currently unplugged, so I don’t think it would bother the Talysman antenna in any way.

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Look nice :wink:
So, I’d recommend you to update to our beta first. If that not help, write here and we will try to solve the problem.


I appreciate the advice so far. I will try this afternoon and will come back to you with the outcome !