Anyone use GPS app for spraying/planting/spreading?

[mjw357]

Looking for a simple GPS app for smartphone or tablet that allows you to set a swath, then records your path around the field so you can keep track of where you’ve been. Suggestions?

 

[hosspuller]

I'm a terrible driver. I leave strips of missed areas. I bought this ... onTrak Agricultural GPS System with simple app control - Agricision Ltd

 

[grsthegreat]

Even a real gps unit can be 20 feet off on accuracy. How good can an ap be

 

[Skagit]

Even a real gps unit can be 20 feet off on accuracy. How good can an ap be

If your GPS unit is off 20 ft that's because it's using the same location technology as your cell phone. A 'real' GPS unit is accurate to about 6 inches or even less (1-2") if you have a base tower setup.

That said, I've sprayed with a cell phone app. It's better than nothing but that's also with a 60 ft boom, if you've got one of those tow behind 7 ft sprayers it's completely useless. Just put dye in the tank.

 

[JCoastie]

If your GPS unit is off 20 ft that's because it's using the same location technology as your cell phone. A 'real' GPS unit is accurate to about 6 inches or even less (1-2") if you have a base tower setup.

No, it isn't, not at a civilian consumer level...period. And GPS repeatability is even worse. I have a background in both differential GPS site and LORAN station maintenance. Unless you are averaging multiple high sample rate multi antenna sources, (not satellites, but receiver sources) you aren't even close to 2", on good occasion 2' can be achieved, but not 2". Many times the space signal can be off more than 2' before you even begin processing it which degrades it further, not improves it.
One of the reasons the FAA does not consider GPS as a 'precision approach"

 

[Skagit]

No, it isn't, not at a civilian consumer level...period. And GPS repeatability is even worse. I have a background in both differential GPS site and LORAN station maintenance. Unless you are averaging multiple high sample rate multi antenna sources, (not satellites, but receiver sources) you aren't even close to 2", on good occasion 2' can be achieved, but not 2". Many times the space signal can be off more than 2' before you even begin processing it which degrades it further, not improves it.
One of the reasons the FAA does not consider GPS as a 'precision approach"

So, ok... You didn't read my post and I'm guessing you have no experience in commercial agriculture. We're not talking about flying airplanes here, this is setting a straight line for field work to reduce crop loss caused by overlap or misses during spraying or cultivation. If you read the last part of my post I referenced using base towers to achieve 2" accuracy levels, that's a ground based tower system such as John Deere RTK, without that you're 6"+ using a stand alone GPS system.

Here's some reading material if you're interested www.deere.com › brochurePDF
John Deere Guidance Systems

 

[Skagit]

So, ok... You didn't read my post and I'm guessing you have no experience in commercial agriculture. We're not talking about flying airplanes here, this is setting a straight line for field work to reduce crop loss caused by overlap or misses during spraying or cultivation. If you read the last part of my post I referenced using base towers to achieve 2" accuracy levels, that's a ground based tower system such as John Deere RTK, without that you're 6"+ using a stand alone GPS system.

Here's some reading material if you're interested www.deere.com › brochurePDF
John Deere Guidance Systems

Edit: Here's the link that works Guidance | Mobile RTK | John Deere US

 

[bdog]

I work with Trimble RTK equipment. Sub inch on the horizontal is easily doable. This is not consumer grade stuff though. I do also use garmin GNSS units and the vast majority of the time they are within 5’ of true location. We have cut thousands of miles of right of way using garmins and then come back with the RTK. It matches up surprisingly well.

Still as mentioned if you have a narrowish boom the error may be approaching the width of your boom.

 

[s219]

Cell phones are good to about 3m (~10 feet) nowadays, but usually do slightly better under good conditions.

I have a sub-meter system for surveying that is considerably more complicated and much slower. But if you have time and want to setup the equipment, then wait for it to converge, it can give about 8" accuracy. Not something I'd want to use on a tractor though, or when any sort of movement is involved. You'd be moving faster than the system can react and converge.

I really like the systems with a fixed base station and then use differentials to work out relative position. Those can be super accurate. But cost and complexity go up.

 

[MHarryE]

I have a New Holland EZ Guide 250 unit which is really a Trimble packaged with New Holland logo. It’s advertised with correction service to give 6” to 8” pass to pass accuracy. Works fine for me for spraying and fertilizer spreading but it’s not accurate enough for planting. Much of my farmland is so crooked - no straight edge on some fields - that I haven’t considered the auto steer option.

 

[Avenger]

I tried a few that I found. But without a better receiver the resolution was too inaccurate. The one I liked the most was FieldBee. FieldBee – GPS tractor systems | Precision farming tools

To get the best out of these apps, you will need to spend some serious money. I decided that I dont need to spend that much for the little field work I do. It would be nice, I went down that road, but in the end, I'd rather spend my money on something else.

 

[Doc G]

To get the best out of these apps, you will need to spend some serious money. I decided that I dont need to spend that much for the little field work I do. It would be nice, I went down that road, but in the end, I'd rather spend my money on something else.

Like a foam marker system? Would that help the OP? Seem to recall some threads where TBN members built DIY marking systems. (I've been wondering about them myself, for spraying.)

 

[Skagit]

Like a foam marker system? Would that help the OP? Seem to recall some threads where TBN members built DIY marking systems. (I've been wondering about them myself, for spraying.)

On worked ground foam markers work great, on an established grass field they're useless IMO, you can't get the foam streamer to stay on top of the grass long enough to come back on the next pass. They're fairly inexpensive to buy and setup though, just depends on what you're spraying. On worked ground or even right after planting/emergence they work ok.

 

[Cougsfan]

I have tried foam markers and a dye for sprays. Neither work very well unless conditions are perfect, and even then, not that great. I use a 200 gallon spray tank with a 30 foot boom. I installed a Garmin automobile gps in my tractor that I had laying around, and it works much better than either. No it isn't accurate, probably an average of 4 foot of error. But it is a whole lot better than guessing. I go back and spot spray where I missed, and it usually isn't that much. Also it tells me my ground speed. As I have hydrostatic tractor with no ground speed indication, that is as big of benefit as knowing my exact location, especially if you are doing hills where a given throttle setting will go faster or slower depending on the grade. I have looked into more accurate made for farm gps devises, but the expense would be hard to justify in terms of pesticide or fertilizer savings unless you are doing hundreds, if not thousands of acres.

 

[npalen]

My bucket list contains consumer grade gps on the zero turn lawn mower with sub inch accuracy.

 

[Doc G]

I have tried foam markers and a dye for sprays. Neither work very well unless conditions are perfect, and even then, not that great.

That's what I suspected. I tried dye and quickly gave up -- it was still quite difficult to see on growing grass, plus it's a pain to clean out of the equipment. Hadn't tried foam yet but it sounds like it might not be worth the effort. (Mainly spraying herbicide on established grass stands.)

One small point that might help the OP or other folks doing small-scale spraying (like my 12 foot boom): I have noticed that I can much more easily see the tracks from my last pass when the sun is low in the sky, morning or evening. If you set your driving direction (if possible) predominantly N-S, the E rising or W setting sun will enhance the shadow from the previous pass where the vegetation has been bent down. This has its drawbacks, like limiting the time you can work and requiring U-turns each pass, but I can get about 4-5 acres done in the last 2 hours of daylight and see my tracks. It has worked well for me. My $0.02.

 

[RoyalOak]

I am involved in an agricultural robotics company and this is really good input to me. We are trying to use existing relatively inexpensive technology to get this kind of accuracy at a reasonable cost. "Reasonable" is going to be more than a few hundred bucks, for now. With RTK (a fixed station for reference) in combination with a GPS device on the moving tractor, the accuracy can be quite precise, but without that fixed station, the accuracy is going to be the same as the consumer grade GPS devices. Any real world comments are very helpful. (The company is Easton Robotics - www.eastonrobotics.com)

 

[mjw357]

Thanks for the discussion guys. The foam marker idea I have kicked around before. On mu small open station tractor, I though about just buying a cheap can of foam type shaving cream and leaving a shot on the ground so I can see where I left off before a turn.

 

[kneedeep]

I use a Field Navigator app with a Garmin Glo antennae for better accuracy.
Works well enough to spray preplant on fields and spread course fertilizer.

 

[bdog]

Garmin Glo units are good. I have four of them that have seen a ton of use in a lot of challenging environments.