# How are the AB lines calculated

How does AOG calculate the line between the 2 AB points? Is it a straight line like Trimble, CNH and Autofarm, or a slightly curved line like John Deere and Beeline use?

More simply, will the lines match my current CNH lines across a large paddock?

Thanks

Based on what I read here about how John Deere does lines vs Trimble, Iâ€™d say AOG will line up with Trimble pretty well. AOGâ€™s lines are parallel to each other, based on rectangular UTM coordinates that are already compensated for the Earthâ€™s curvature. That sounds to me to be similar to Trimbleâ€™s lines. The only caveat would be that you probably need to start your first field and first line in the same spot on AOG as you would in Trimble. The reason is that when you first create a field, the UTM grid is â€ścorrectedâ€ť such that a heading of 0 degrees is actually true north. Subsequent parallel lines to that will start to change ever so slightly in actual GPS heading (Trimble lines do the same thing). Whether they are straight or actually curved is a matter of perspective!

Apparently pass to pass Deere lines (beeline) are not parallel but rather each share the same actual GPS heading, which means if you go straight north they will all converge at the north pole. And as you say other headings will curve slightly. Ahh the joys of trying to do straight lines on a curved surface.

I guess my fields are short enough that Iâ€™ve never noticed any real problems with my Deere and Trimble straight paths diverging.

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Thanks for the info torriem. Sounds like they should be alright.
I changed a Beeline system for a Autofarm on a cotton farm with raised beds once. Lines were fine at the ends where the points were, but half way down would start knocking over the beds. But these were pretty big paddocks.

Correct Torriem, originally AOG never compensated for being straight north at the start of the field, so that was a good fix. Never really sure how all the different mfrs do their calculations but have found that with Trimble in our Case 500 where we have both, AOG calculates exactly the same way and the line is dead on across a half section (1.6 km)

Do you have AOG driving your 500 yet? Or just doing section control and mapping?

I hope to get that going this spring - but oh my so much harvesting to do first. I wish i had a heated shop.

Was wondering if i could just change the solenoids in the autosteer control valve and control them with pwm. They are all canbus right now of course

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Oh man!

Iâ€™ve no doubt itâ€™s totally doable to replace the head with pwm.

Or canbus is also a possibility. Iâ€™ve got quite a few projects in mind involving canbus. By summer maybe Iâ€™ll have to find out what messages are originating from the NAVII controller and heading to the steering valve. Canbus can be noisy because of the broadcast nature of it, but sniffing across a bridge makes it a bit easier because you can focus on messages originating from a device. I canâ€™t think the steering valve messages are all that complicated.

I was told the valves on the case artics use a ratiometric proportional control rather than PWM, couldnt plug our old autofarm into the valve block. Anyone familiar with ratiometric control?

Maybe it is a Danfoss valve?
I think solution is found here .ino for PCB+MD13S+Danfoss valve
[

### Danfoss PVG proportional control valves - Hi Power LTD

](Hi Power LTD)
hl=da&sl=en&u=Hi Power LTD)

Danfoss PVG proportional control valves â€¦ as default on all valve sections; Hydraulic actuation; Electrohydraulic actuators PVE ( Ratiometric , 0-10V, CANbus) as

Ratiometric generally means output based on supply voltage. For example, a thermistor temperature sensor may have an output of 50mv/volt so the overall output or range depends on the supply voltage powering it.

Now inherently, all valves would be ratiometric since the more voltage across the coil for the same proportional on/off cycle would allow more oil to flow. As the voltage goes from 12.6 to 14.4v the valve output will change accordingly.

Taking advantage of the initial topic, and apologizing for the English translation.
Perhaps it has already been discussed on some forum page, but what would be the basic configuration to operate only in line following the pattern of the outline made at the beginning?

Always in line without turning.

Thanks!

Are you referring to contour?

I am looking for a low cost solution. Very low (income from a small Brazilian producer). Pilot in line.

The software is free, the hardware is quite inexpensive.

Taking advantage of Brian Tee, I want to congratulate the work of everyone involved in the project! Great.
My question:
Iâ€™ve been studying the forum since the first post and I realized that the use of AgOpenGPS is getting very professional and \$\$\$\$ due to the precision (itâ€™s the natural way).
I would like to know from the veterans if I can use AgOpenGPS with low cost GPS (Ublox M8N or GPS USB) to work in line from point A to B. Without making the turn at the end.
There is a very large group of farmers who work with scrapped machinery here in Brazil, it is not cheap to keep up with technology.
I thought about using the following configuration:

• BNO 055
• MMA 8452
• WAS
• GPS M8N
• Steering motor

Could I do a satisfactory job?
Would my direction error be too big?

Thanks!

Sorry my english from google translator.

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RTK, ardusimples â€¦ a lot of precision does cost a lot of dollars.

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Compared to what is being sold on the market today, AOG with RTK is not \$\$\$\$.

However I believe your M8N could work fairly well for many purposes, even with just GPS accuracy equivalent to WAAS.

If you build a system using AOG, and find that your GPS is inadequate, then it is quite simple to replace the GPS with something better. This is unlike commercial systems.

So itâ€™s worth building an AOG setup with the hardware you mentioned.

To further reduce cost, you donâ€™t need the bno or the MMA. If you have relatively flat land, just the gps is fine.

Hello Marcio
Personally I think that without RTK correction you will be quickly disappointed even for manual guidance.
With an M8n the precision will not be regular.
The advantage of RTK kits like Ardusimple is that they are very easy to use and that there are a lot of people to help you here in case of problems.
This is only my opinion but I think that the money spent more at the beginning will quickly recover and the high precision will allow you other uses.

Donâ€™t waste your money with the M8N you will be disappointed very quickly, if ardusimple is too expensive for you try the M8T with RTKLIB insteadâ€¦

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