Ntrip issue

Hello,
I have looked in the forum and I hope I am not creating a duplicate.

Issue: I have the subscription to a local NTRIP service but I am not confident with my measurements since after a testing several mount points and repeating measurments over the same the same place I had different results (points far around 2-3 meters even if I didn’t moved the receiver).

More in detail: my ntrip service provider gives corrections from the NEAREST or from a VIRTUAL base station using different “formats” (i.e. RTCM3, RTCM2.3).
1: not all of them work in my Reach unit (reach view v2.16). It only worked with the nearest station and RTCM3 format. But in my test case it resulted in a baseline of 18 km and I guess that with L1 it is not that accurate.

2:having the receiver placed on a tripod I surveyed the same point using all combination af mountpoint. It resulted a bunch of different points far from each other some meters (<3m).

In the figure below the point named “float” is actually the unique fix solution achieved with the NEAREST station (18km) using RTCM3. After 1 hour I tried the stakeout tool (with the receiver always in the same point) to verify repeatibility and it resulted 80 cm shifted (sorry, I have no screenshot of the stakeout test).


I have recorded all row files and corrections for each attempt and if it is useful I can upload them.

Follow some screenshoots of my setting and status using the different mount point (i.e. changing RTCM format and near/virtual reference station).

Nearest station in RTCM2.3 format -> it gives always a 30 m error


Virtual station in RTCM3 format -> no correction

Which is your opinion regarding the strange behaviour with this NTRIP correction provider? Do you have any suggestion?

Goodbye,
Marco

Ps: In addition the previous day I gave the receiver to a colleague to make a survey in a site 1 km away from a NTRIP base station fo the same network and, even after several hours, he didn’t achieved a fix solution. But in this case it could be a explained by the really low satellite visibility since the site is 100 m away form a steep cliff. Sorry I don’t have any record of this.

Hi Marco,

It’s better to work with the baseline that is less than 10 km. Have you tried to post-process logs?

RTCM2.3 is an older format, I think you’d better use RTCM3.

Could you press on the arrow on the right to the IP address (see the screenshot below)? There should be received messages. Please make a screenshot and post it here.

Hello Tatiana, thanks for your message.

It’s better to work with the baseline that is less than 10 km. Have you tried to post-process logs?

Yes, I know. But the point here is that I am trying to have RTK with network NTRIP correction working. So the only working mountpoint was with this “near” station. Of course my optimal solution would be to work with VRS so, I would like to understand the reason for which the VRS correction is not working.

Could you press on the arrow on the right to the IP address (see the screenshot below)? There should be received messages. Please make a screenshot and post it here.

Here is the new screenshot:

Goodbye,
Marco

Why not just use your own base, and then use the nearby NTRIP to establish the base position?

That would eliminate your issue.

Marco,

Reach requires 1002 and 1006 RTCM3 messages. It might be the reason for corrections absence.
Can you reach out to your NTRIP provider and ask about the possibility to receive these messages?

Tatiana,
thank you for your reply. I will check it.

Hello Christian,
Sorry but I don’t get your solution.

My idea was to take advantage of the RTK NTRIP service in order to use of my Reach RS (in standalone mode). In my opinion the VRS corrections would have tackled the limit of baselines longer than 10 km wih L1.

Yep, I see that, but I haven’t been able to use VRS so far with the RS+ either (Danish NTRIP provider).

But given the cost of these subscriptions to NTRIP, isn’t it cheaper to use your own unit ? A subscription here is 1600 eur per year… I can buy 2 Reach RS+ units with that. I do see that there is less setup/configuration time with the NTRIP solution (if would work as intended using VRS).

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