Hey All,
We built a setup on a Deere 7320 that hardware wise seems rock solid. Phidgets 24V motor, v4.5 micro AIO, dual GPS. Autosteer is dead on and the tractor goes exactly where AgOpen tells it to. Line/Track error stays at 0-2 ones acquired. We’re very happy with this. We have a RTK Base, via RTK2Go that is 500 feet from where we were testing.
Note - I’m the computer guy behind all this not the farmer so excuse me if I get the farming terms wrong 
Now the confusing part. We were testing in a field today, we drove the boundary and created a quick straight AB line from the east boundary, headed towards the middle and did some testing. What we found was confusing.
With rows headed in the same direction we get dead nuts on accuracy. We stuck a flag in the ground, circled around and had it reacquire the same line and the flag ended up in the pin hole on the drawbar, amazing. We did 4 rows in the same direction and they’re exactly 15’ feet apart (150" tool + 30" gap)
What isn’t working is that when doing normal up/down rows we are seeing inconsistency in the gaps, sometimes it’s 4" over, sometimes 4" under, we also saw twice where it did a row 1’ under, and the next 1’ over, making the two rows come out to 30 feet (2 x the section width), that seems suspicious.
Do we fundamentally misunderstand how this is working? Shouldn’t they all be evenly spaced? Or is it trying to do some crazy math to fit them in between the boundaries?
The reference line was set at the east edge of the field used for AB creation and we were working 3/4 of the way over in the field at R25 or so.
We feel like we are so close and spent 4 hours in the tractor today just trying to get some consistency.
Edit - We’re testing using v6.6.2 and 6.4.x
Seems almost identical to this - AB Guidance line is incorrect - Bugs-requests - AgOpenGPS
The GPS antenna offsets are all set correctly, “Right” is picked and the antennas are evenly spaced from the centerline
How far away is your field origin from the actually field? Did you create the field in AOG while physically close to the field?
This test field is just under 9 acres so we just drove it to create the boundary. What do you mean the origin vs the actually?
I found another post saying that turning the integral off for autosteer may solve this. We’ll need to try that in the real world as the simulator doesn’t show the issues.
Okay this might be something.
In the tractor config I have the antenna offset set to 31" and “Right” however if I look at “All settings” it’s showing the antenna offset is -0.78 (which is in meters). All of the numbers were put in by hand after calculating them on another laptop
Shouldn’t the offset be positive for the right antenna?
Now get this, if I rerun the autosteer wizard and don’t clear the defaults it shows the antenna offset as -31. If i change it to 31 and finish the wizard and go back to the tractor config it’s now set to 31 and “Left”
Is this the issue? Is that intended? Why is the wizard picking “left” when the tooltip is saying “Dual position antenna on right”?
You should believe the default.
There is a difference between THE right and To the right.
What you do is moving the right antenna further outside the tractor to the right side.
With dual/equally spaced antennas shouldn’t it not matter if the offset is left or right, because that’s the same distance from the centerline?
In any case the “** Dual Position antenna on right” note on the antenna offset page makes it sound like you need to select where the right antenna is. Sounds like you’re telling me that’s not true.
Everything in AgOpen I can think of treats positive numbers as the right side as the tractor is facing forward. Having it put a negative offset in for “right” seems inconsistent.
I’ve just setup Dual on a tractor, I set the position antennae as right with an offset of 73cm (antennae are 146cm apart and centred over tractor).
Drove an AB line in one direction and returned the other and it was spot on.
Is your wheel angle sensor zero set correctly?
Yes it’s zero’d. We can do unlimited rows in the same direction (aka A to B) and the rows are exactly 15’ apart. As soon as we UTurn and start going B to A there is an offset from the A to B line next to it.
Looking through the source code there is a comment on the antenna config that says “Negative is to the right” so the “all settings” config showing a negative offset for the right hand antenna is likely correct. Back to square 1.
Is B to A, B to A, B to A. Always wrong also? Or is it just A to B then B to A that is the problem?
Check your imu roll Sensor. Or check to see if the antennas are sending the same elevations when level.
It seems like every two rows even out to 30 feet, we did about 4 hours of testing and eventually gave up for the day. Driving A->B and then B->A might be a foot short, but then add another A->B and its a foot over.
But do 4 passes A-B and they’re all < 1" accurate.
No IMU, just Dual GPS. Roll has been zerod and the tractor shows correct positive roll when tipped to the right as the direction of travel.
Antennas are facing the same direction (antenna cable coming out the same direction)
Here’s the vehicle config - <?xml version="1.0" encoding="utf-8"?> - Pastebin.com
you have the config like this:
and how much is the distance between antennas? 156 or 78
If you have 156cm from one antenna to the other your offset=78, now if in total you have 78 your offset=39.
If you have this configured correctly, remember that all implements have errors, they are not perfect and you have to correct their offset.
The antennas are 62" from each other (31" in each direction from the centerline)
We are testing with no tool attached to the tractor and measuring from the drawbar pin.
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I see your Ackerman is at 100°, which means that the wheels, whether full right or full left, give you the same angle.
Could you calibrate the Ackerman and try again?
We’ve been flipping between laptops and this one may be a slightly different XML, I think the other tablet has it at 104 or 106 which seems sane.
The tractor is showing dead nuts on the line on the map, so it’s where AgOpen wants it to be, but where it wants it to be is wrong, it seems.
How much offset error do you have if you come back along the same line? So drive A to B, mark center of tractor then turn around and come back along the same line in reverse direction.
To rule out a roll issue, set the height of the antenna to as low as it will go. And try again.
Just so it is said. And I’m sure you are aware. Tractor tilt to the right shifts the Tractor on the screen to the left away from the line. The higher the antenna setting the worse the shift.
Not sure this is your problem, but setting that height to zero or as low as it will go minimizes this and you can focus on other settings.
Also, if this height is wrong and you are on a hill, the roll of the tractor will cause this also.
Another test, with the tractor sitting still raise on of the antennas. The tractor on the screen should shift towards the antenna you raised.
Another thought:
Not sure how you flashed your f9p, but both have to be set to high precision to get any vertical accuracy.
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I appreicate all of the ideas. It’s going to be a week or so before we can get back out into the field to test.
The F9Ps were flashed with ConfigOMatic, with the suggested firmware and the correct left/right dual configs.
Roll on the display always seems correct (0-3* or so based on where we are) and I can’t see that making a row a foot off.
