Fendt variguide

[Robt]

Could you please explain once more a previous statement you made.
You said that a customer of yours had started using auto steer and had managed to get MORE passes in the field than before? I really don't get this as he must have been missing bits before, or have I miss read your previous post.
Sorry if I have, just a little confused

 

[Northern farmer]

Thought I would update my experience the last 3 months !!
First thing is to say that I do live and work in a bad area ref mobile phone coverage with plenty of hills and valleys and also point out that I work over a 25 x 5 mile wide area and from sea level too 1200 ft high. I bought a 724 fitted with variguide from the factory with the rtk module with a roving sim card. However I did nt fit the sim until September 14 although I used it with egos to good effect. Basically since the SIM card I have done 450 hrs with the tractor but have only had 1 ten hour day where rtk worked 100% and the rest of the time it has not. It either can t connect from the start or just drops out and again it's 50:50 if it connects again. Had plenty of days where I get half days then nothing! Dealer knows and excepts it's very poor and I m told agco are also aware. I ve basically told them I want my money back as it's not fit for purpose but I am waiting for promised updates in February when tractor gets a service. When it works it's brilliant but obviously I m not getting enough times when it works!
If your thinking of this system then please have it on trial for a month before parting with money. I really hope they get it better but will have to see. Only option I have other wise is a mobile mast which I move around but that is dearer and as yet unproven in my area.

I interpret the issue really being a dropping mobile connection? A roaming SIM might make things worse in the sense that the modem may switch between networks while you are working in the field and this means a new IP address and definitely an new NTRIP session etc. etc. You should be able to lock the roaming SIM to the best network of the area, unfortunately the user interface does not support this. It is not easy enough either to swap the SIM card for the best local signal. At my place NTRIP connectivity is perfect but if it isn't in where you drive, RTK from a radio mast should be used instead as Robt says above.

I'd like to learn more about your experience, have you had other issues in addition to dropped GPRS calls? You say it reconnects at a 50% likelihood? I know the (Motorola) GPRS modem behaves oddly when attaching to the network an establishing the GPRS connection (probably not only an issue of the Motorola modem but also how Topcon/Fendt uses it). If the tractor has the latest SW, you should get connected every time, it just sometimes takes longer than necessary. Ideally this should only be an issue first in the morning but if you get dropped calls, the issue repeats during the day.

The radio based RTK has its drawbacks too if used at a too high distance, there is no similar option to calculate a virtual base to the tractor position, making use of several surrounding fixed stations.

 

[Robt]

Egnos does not use Glonass! The correction does not support it!

 

[Docwalters]

Could you please explain once more a previous statement you made.
You said that a customer of yours had started using auto steer and had managed to get MORE passes in the field than before? I really don't get this as he must have been missing bits before, or have I miss read your previous post.
Sorry if I have, just a little confused

Yes, he was missing bits before when drilling by eye.

 

[Robt]

Missing bits!!!!,! Wow that's a new one to me. Never met a drillman that sets his markers wide! Guess he wasn't using markers. Fair play though for getting him more accurate.

 

[Docwalters]

Egnos does not use Glonass! The correction does not support it!

Should I have said Egnos or Glonass. We do both.

 

[Docwalters]

To be fair the whole auto steer thing coincided with him having a new drill.
Maybe that helped.

 

[Robt]

Glonass is not a correction source? How are you using Glonass as a correction source . Or are you tracking raw GPS using both Glonass and gps sats?

 

[Docwalters]

Glonass compensates for the inaccuracy experienced during certain times of the day by the current satellite infrastructure.

 

[Robt]

Yes but if you are using egnos, you don't get glonass, or are you running on non-diff.
Sorry for all the questions!

 

[Northern farmer]

Sorry but you are incorrect.

Firstly who puts an antenna IN the cab. It's meant to be located as high as possible on the OUTSIDE of the cab. It is, after all, reaching for a sky-borne signal so it makes sense to get as high as possible to receive that signal away from lumps of metal etc.

Secondly, we use a patch antenna which gives us excellent results being a powered antenna. Not all patch antennae are powered. Not all patch antennae are the same.

Thirdly, drift does not occur on every pass. If it was that inaccurate no one would use it.
Satellite drift occurs significantly about every 20 -30 minutes, that is it can take about 20-30 minutes for the Egnos signal to go a little wobbly and drift by about 20cms.
But not all products are the same since different software interprets the signal in different ways.Some will latch and hold. Others will buffer the result to allow for a more soft-edged change in signal.
We all know satellite drift occurs;it's the nature of the beast but it is not that fast and some equipment, like ours and others, can be recalibrated for satellite drift on the fly.

Fourthly, if you are using a one metre overlap for your fert spreading then you defeat the whole point of using GPS in the first place. If you spread to 20 cm accuracy then your overlap should be, at most, 20cms. In practice, with a good signal and good differential, accuracy can be seen as less than 20 cms and with auto steering significantly less since the autosteer operates far more quickly than the human brain for eye-hand communication.

Does that all make sense?

You did not quote anyone but replied just after my message, I assume you are referring to my post? If yes, then no, not all of that makes sense to me.

I said all EGNOS level receivers from major brands are exactly equally accurate (at 20 to 60 cm level relative accuracy, give or take one cm, makes no difference), we both assume a properly installed antenna. We should conclude then that the Patchwork receiver running EGNOS is as good as any other, and vice versa. There is no "latch-and-hold" implementation, sorry. On EGNOS only it does not make a big difference if you have a proper antenna or just a path antenna (so I don't exclude your receiver from those that give good EGNOS performance).

I've never said EGNOS would not be a good solution for many farmers and for many applications, I just said EGNOS has poor absolute accuracy and has significant drift. I never brought the cost aspect because it is impossible to assume that the cost versus performance trade-off is the same for everyone. EGNOS simply isn't enough for all applications (while unnecessarily high accuracy does not hurt any application, may hurt the wallet though).

I'm referring to previous posts on this forum where EGNOS drift was observed to be too high even during a single pass, not from one pass to the next. Some have a mile long field which we have to take into account. Even on shorter fields it does not make a big difference if EGNOS offset is sufficiently small once in a while if it most often is too high, then you anyway need to check offset for every pass. EGNOS is not good for drilling unless you are willing to accept the compromise of doing continuous manual offset corrections. A matter of opinion if that is more convenient than manual steering (I accept the fact that opinions are different here).

You have some drift in the EGNOS performance figures too. The figures we usually talk about are for a 15 minute period, not for 20 to 30 minutes. 20 cm is optimistic even for 15 minutes (at standard confidence) but even there already much too high for any high accuracy work like drilling, unless manually compensated.

I don't know where did you get that 1 metre overlap? I'm using RTK and do not need any overlap. Why are you promoting autosteer for me? I'm all for autosteer anyway. But autosteer does not make the GPS receiver any more accurate, the 20 cm error is there and on top of that comes the operator error, human driver or autosteer.

Please note that I have nothing against Patchwork products or EGNOS as such. I just don't accept too optimistic claims on EGNOS performance (from any receiver brand, be it Christmas time or not).

 

[Oscar]

Robt, would be good if your getting closer to me ! I know I am the odd one out as I m the only person in my 25 mile area doing RTK and all my dealers are not going to put up masts as 1, they are all out my area [Taunton and Bridgwater]and 2, not many people are looking to go RTK. This is my problem also as due to the problems of distance and contours, even a mast in the center of my area would only service at best 50% of my area.
Only thing sugested the other day and done was to switch off Glonass as my unit was searching for 16/17 sats where as on Egnoss its 10 or so. Was told the unit can t cope with all the data from 16/17 and after turning off it does sometimes pick up quicker but still as said drop out too often.Last 10 days I ve ploughed a bit [40 hrs or so], best I got was last Tuesday 8.45 am - 12.15pm ,100% then dropped out for 2 and three quaters of hour[did nt connect at all but said "N Trip with green tick" but would nt move on]. It then reconnected out the blue and worked for about an hour and then came on and off for the last hour or so. The other days I got a hour at best and then long periods of nothing. Should add ,this was in a 40 ac field on top a hill and a 25 ac field next door and my mobile phone worked 100% the whole time.
It would be good if on the screen it told you which mobile signal it was tuned too or trying to connect too.

 

[Docwalters]

Yes but if you are using egnos, you don't get glonass, or are you running on non-diff.
Sorry for all the questions!

No Robt. You are correct Egnos and Glonas are two entirely separate technologies

 

[Robt]

I think you aren't always getting good advice! To be told that you should turn off glonass to improve it is poor advice! Your issue is data coverage. I'll have to get my colleague to do an Rtk survey on your farm with our mast trailer. We set up an Rtk base then check signal. You'd be surprised how far it goes and over what terrain. You say no one else is using Rtk so no interest. You'd be amazed at how many are looking at RTK.
Please call my colleague or email me your details
[email protected] or my colleague that covers your area [email protected]

 

[Robt]

Thanks doc,
You got me all confused by saying
"
Glonass compensates for the inaccuracy experienced during certain times of the day by the current satellite infrastructure.
"
It can't as you aren't using it on egnos. It's only used on Omnistar , SF2, Rtk and some of trimble's own correctional signals.

 

[Oscar]

Ok thanks, will do so later!
The advice ref glonass was to see if it reacted better and in the particular field I was in at the time[few weeks ago and different area to last week] it worked as I had no connection for 3 hours but after turning off Glonass it connected almost immediately. This was not a long term fix rather than a "look see".
I ve been told again today by my dealer rep [think he is reading TFF] that the updates coming any day will improve things greatly so time will tell.

 

[Northern farmer]

Ok thanks, will do so later!
The advice ref glonass was to see if it reacted better and in the particular field I was in at the time[few weeks ago and different area to last week] it worked as I had no connection for 3 hours but after turning off Glonass it connected almost immediately. This was not a long term fix rather than a "look see".
I ve been told again today by my dealer rep [think he is reading TFF] that the updates coming any day will improve things greatly so time will tell.

The above sounds like the issue with the RTK correction signal that was discussed earlier at this forum. You have to have the RTCM 1033 (if I remember the message number right) message included, it allows the receiver to identify the base brand and then resolve the ambiguity in the correction signal.

I've tested this a lot in the early days of running my own base. I think a very early implementation of the Topcon AGI-4 receiver was not using RTCM 1033 but you cannot have that old SW.

 

[Robt]

Varioguide is not running Topcon AGI-4 soft/firmware.

 

[Northern farmer]

Thanks Robt for correcting my mistake. I should have talked about the VarioGuide RTK receiver (I guess a Topcon AGI-4 running some AGCO/Fendt SW, no idea if it is completely made by AGCO or at some higher layers only).

Having another thought on this compatibility issue, are there actually correction signals that lack RTCM 1033? If the signal provider wants to serve all receiver types, they should have this message included.

This was a bit off topic, sorry about that.

 

[Fendt Power]

I need help with implement offsets does anyone know where to enter the implement offset I've got a fendt 936