NTRIP - BASE - Rover setup up VS NTRIP - ROVER DIfferent Results

Hello,

New user - just received my 2 Emlid RS2 receivers… i have set them up as BASE and receiving corrections through NTRIP provider and ROVER receiving over LoRAH.

I made sure that the NTRIP and my SURVEY have the same COORDINATE system in this case ( SWEPOS 99 1800 RH2000 HEIGHT ) and made sure my pole height was correctly set to 2meters.

After collecting the points through this set-up. i decided to test the Rover over NTRIP and try to stake out the same points i collected by just using NTRIP and Rover. I made the changes in the settings to receive corrections through NTRIP. ( Yes, all points were FIXED when collected)

Immidiately i realized that the Elevations i was getting were off by i would say roughly 8-10+m.

for example… During the NTRIP-BASE-ROVER set-up i got elevation point 58.3m - when then switching to NTRIP - ROVER i was getting 45.7m. for ex.

Also, i tried staking the point out and i was waaaaaaaay off with the ROVER - NTRIP set-up… so now i am confused as to what is accurate or what i maybe missed in the set-up process.

I have watched and read ALL the videos and text tutrorials multiple times and still cant figure this out.

Please help ! THank you

How did you set up the base coordinate?

BASE is over NTRIP - I went into the settings again after i wrote the post… I noticed it was set to Average Single - I have changed it now to AVERAGE FIX.

Think this might be the issue… will test it to make sure the NTRIp - ROVER set up matches the BASE -Rover Set up… but if you have any further recommendations to the settings to get absolutely accurate results - please do share them, Thank you!

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Are you absolutely sure the base station you are accessing through Ntrip is in the specified coordinate system?

The National Swedish COordinates system is SWEREF 99 TM then the country is divided into zones 18 00 is for STOCKHOLM area which i am in. All city and municipality DWGs are in this Reference system as well.

I pasted the link down below ( its in english) if you can take a look and maybe you can see something that i dont.

And this is the info for the MOUNT point: MSM_GNSS RTCM 3.2 MSM4 GPS/Glonass/Galileo**

The position is correct - As i was testing everything in my Garden around my house. I think the issue was that i had set Average Single on the Reach Base instead of AVERAGE FIX. i will test it again tonight and have the base average its position for 5 min and then test the Rover connected to the NTRIp and see if i can stake out the same points.

Thank you for you assistance!

This is exactly what happened. The base position could differ up to 10 m depending upon how long you let it collect the average. Normally we would average fix, document the coordinate and then manually enter it. Mostly because we revisit the same site many times and want to maintain that single base point.

It doesn’t seem like a different coordinate system would make the measurement different because everything would be relative to the base. The whole network of points may be in a different place but point-to-point distance should be the same.

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Do the areas of your points have a clear unobstructed view of the sky ? You posted “As i was testing everything in my Garden around my house”. How close to the house ? Is the garden overgrown or does it have a lot of trees ?

Just because the receivers indicate “fix” doesn’t mean that the coordinates shown are correct.

Can you take pictures of the areas where the receivers are ?

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HI Bryan,

Yes receivers were in the open and unobstructed. There is one tree at either end of the plot but the base was set in the open. I did check the coordinates with the municipality online map… without paying for a map - you can trace over with the mouse and the Easting and Northings will show and it seems that the results are accurate now that i switched the base to AVERAGE FIX - this was my issue i believe… It threw me off also as the “open Street” map thats on the REACH View 3 app shows the points on some parts of the house. but when i checked the municipality online map - they were spot on.

Hard to explain / confusing…

The testing that i had set to Average Single on the base - showed the points on the Open Street map correctly away from the house. However, when i traced these coordinates over the municipality map - they were way off and were somewhere in my neighbours yard.

The AVERAGE FIX test showed points on the open street map in REACH view app on top of some parts of the house but they traced correctly in the municipality map :face_with_raised_eyebrow:

I have a DWG from the municipality for a clients house that i will stakeout and test during the week to confirm i.e. If the points i take in the field on the clients property show up as "on top " of house (as it did around my house and today at another clients house when i collected points) vs. the municipality DWG and that the receivers are accurate and my problem is resolved. But i am fairly confident that the issue was that i had AVERAGE SINGLE instead of FIX.

I am very thankful to everyone that has responded, what a great community and so many eager to help. Great to see!

Thank you!

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Hi @sin,

Now you can enjoy what we all love about this community - the ability to effectively guide you through the most difficult parts of the survey scene :heart_eyes:

I just wanted to add a few things here. If you require the centimeter-accurate absolute position on the rover, it’s necessary to have your base coordinate down to a centimeter as well. This is not always easy, but this is where all talks about accuracy start. There’s no way to avoid it.

I can see that you can average your base with the use of the NTRIP. That’s cool because you can have the absolute centimeter-accurate position of your base right from the beginning. Then, make sure to insert this coordinate manually, and don’t forget to exclude the antenna height. Should be working great :slight_smile:

Please share with us your results when you’ve tested!

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