Trimble RTK issues spring 2020

[warksfarmer]

Anybody had any issues? We’ve had some wandering between drill fill ups so a 20 minute delay between passes. See picture. It’s a very minor gap that won’t be noticeable in a few weeks but it’s consistent. Anybody know anything about countrywide coverage issues. Case AFS700 Pro system.

 

[Northern farmer]

Perhaps obvious for local people but who is the RTK correction signal provider? VRS or single base? If single, is it always the same base?

 

[clbarclay]

I don't know about RTK, range point seemed to have a lot of drift yesterday during one refill. It seemed to come back during the next hopper full, but while drilling the next feilds headland it was still about a meter out from where it should be.

 

[warksfarmer]

Perhaps obvious for local people but who is the RTK correction signal provider? VRS or single base? If single, is it always the same base?

VRS.
It’s always been spot on compared the the JD RTK system now sat on the shelf but it’s to consistent for it to be temporary blips which you get now and again.

 

[Northern farmer]

Don't have experience about RTK but a private base and I've never seen even a temporary blip. Cannot see how that could happen if everything is set up correctly. Perhaps some temporary misbehaviour of some Russian satellites? I'd still expect issues to get fix rather than random position errors.

VRS could be calculated to a very distant position and perhaps has some variability because of that but it should be marginal. The only obvious drift with RTK would be when changing between base stations and one or the other has incorrectly configured base coordinates.

I have not found a good website that gives GLONASS health data. Perhaps the reason for the unusual rangepoint issue clbarclay mentioned.

 

[warksfarmer]

Don't have experience about RTK but a private base and I've never seen even a temporary blip. Cannot see how that could happen if everything is set up correctly. Perhaps some temporary misbehaviour of some Russian satellites? I'd still expect issues to get fix rather than random position errors.

VRS could be calculated to a very distant position and perhaps has some variability because of that but it should be marginal. The only obvious drift with RTK would be when changing between base stations and one or the other has incorrectly configured base coordinates.

I have not found a good website that gives GLONASS health data. Perhaps the reason for the unusual rangepoint issue clbarclay mentioned.

I say blip because you couldn’t tell in realtime and the coverage maps were fine. It’s literally 4 inches out if you stop to fill up.

 

[Northern farmer]

4 inches is way too much, about equal to one carrier wave cycle, instead of a fraction of the cycle as it should be. As if the RTK fix was one carrier cycle off.

I hope you will find a solid explanation for this issue and report.

 

[PSQ]

If a Trimble sub has lapsed then the signal may *automatically* default to Egnos, so perhaps check to see if your actually using RTK.
Paying the sub will not automatically connect to the subscribed level, you may need to manually select your correction source in settings.
And yes I have learned this the hard way, looking at gaps the length of the field and thinking "WTF?!", with a correct upgrade key entered prior to drilling (FM-750, so may not be relevant to Lee's situation).

 

[warksfarmer]

If a Trimble sub has lapsed then the signal may *automatically* default to Egnos, so perhaps check to see if your actually using RTK.
Paying the sub will not automatically connect to the subscribed level, you may need to manually select your correction source in settings.
And yes I have learned this the hard way, looking at gaps the length of the field and thinking "WTF?!", with a correct upgrade key entered prior to drilling (FM-750, so may not be relevant to Lee's situation).

We get an alarm if the signal drops or changes, but to be honest I’ve never known this system drop levels. In the 3 yrs of using it it’s been either full RTK or nothing.
It’s bang on if continuously used but it’s literally shifted about 4 inches every time we’ve filled the drill up.
I should also point out we were running back to the yard to fill, so no seed in the field so we are leaving the boundary and then returning if that makes a difference. Saying that we’ve done that loads of times before without issue.

 

[matttargett4]

its not really much help but i had a free 6 month demo of trimble vrs, its was complete dog sh1t, the line would move overnight, signal loss around trees was awful.
we were running egnos, range point and vrs at the time, rangepoint was by far the best, you expected drift on egnos so accounted for it, the vrs sim was just neither and expensive.
we since put up a fixed base and host our own n trip using rtk to go and co7ldnt be more pleased, on 4 tractors payback was sub 2 yrs.

 

[Northern farmer]

Interesting. Perhaps Trimble does not have a dense enough VRS base grid as they must have put priority for rangepoint and centerpoint. If correctly implemented and if the base grid was good enough, VRS should provide an equal experience to RTK from a single base (this is what I've understood, as I said above, have no personal experience about VRS, also running a private RTK base).

I still would like to see the technical explanation for the drift when filling. Guessing the VRS would be recalculated while the tractor was driven home and back to the field. Perhaps test turning the receiver always on at the field, at about the same place.

 

[Savage]

i had an issue with the xfill backup for RTK on New Holland where the frequency needed to be changed.

 

[Soon_60]

If your nudge settings are not changed when U go to refill then it might be a difference in the implement drift between empty and fully loaded drill?

 

[warksfarmer]

Sorry I’ve not been clear we are using Centerpoint RTK.

 

[Northern farmer]

The definitions for Centerpoint RTK versus Centerpoint VRS are very confusing to me at least.

From this site: http://www.precisionagriservices.com/gps-1/centerpoint-rtk
I understand Centerpoint RTK correction signal can come from a network of base stations but only one base is used at a time. Basically a single base always but the closest base can be selected? Not sure if their RTK uses radio transmission while VRS should only be practical over NTRIP?

VRS uses simultaneously multiple base stations close to the receiver location. Based on many base stations a single virtual base is calculated as if it was close to the receiver.

Theoretically the reference base for Centerpoint RTK might change from time to time but there should be no drift as long as every base has been configured correctly. It does leave room for an error scenario where the coordinates of one base are not accurate. I would expect this to be very unlikely. I guess you can see the ID of the base at some receiver menu, check if it changes.