GPS Precision Farming Accuracy

[Lineman North Florida]

With my Raven GPS unit I don'i need any tri-pods or anything extra, just the receiver that I mounted on top of the tractor and the screen inside the tractor , the way I understand it it's a lot like GPS tracking collars that I use on my hunting dogs and they both use satellites to triangulate the position and they will put me under the palmetto bush where the dog is layed up. It wasn't really all that hard to farm before all this stuff, I remember laying off rows for bedding or planting when I was a boy, my dad would have me lay off a track with the bedders or planters up, if the track wasn't straight enough to suit him, he would have me lay off another one, once I got one straight enough to suit him I would set the planters or bedders down and lay my row marker out which would give me a line to center on to come back everytime, I actually got pretty good at it and could go out and do it again tomorrow if I needed to, but now we were only planting 4 row, nothing like these guys use today, but the principle is still the same.

 

[LouNY]

Depending upon your application, it is what will decide the accuracy you will need.
50 cm is almost 20 inches, about worthless for ag.
8 cm is just over 3 inches, plasable for broadcast seeding or fertilization,
not accurate enough for strip tillage or other more precise work.
5 cm is about 2 inches pretty good for some applications.
2.5 and 3 cm about an inch, plenty good for all applications if used on the implement or the operator is competent at making the course corrections without throwing everything off in subsequent passes.
So it takes a good highend system to preform adequately for strip tillage and fertilization or planting.
From Raven:

GNSS Corrections​

Seamless and accurate navigation solutions

Our Global Navigation Satellite System (GNSS) correction options deliver highly accurate, reliable Differential GPS (DGPS) positioning using WAAS, EGNOS, GLONASS, and satellite GS-based DGPS correction options for our high-performance receivers. Our capabilities range from sub-meter to sub-inch accuracy, making them ideal for precision farming, GIS, and other rugged receiver applications.
Please note: Achievable accuracy and convergence time may vary based on capability of receiver, antenna, ionospheric activity, and multipath environment.

GNSS Correction Options​

		REPEATABILITY (95%)	PASS-TO-PASS ACCURACY (95%)	CONVERGENCE	UNLOCK	SUBSCRIPTION
Autonomous Solution	Autonomous solution comes standard with all Raven receivers. Usable in areas without SBAS availability.	240 cm	35 cm	<10 min
SBAS	SBAS includes area specific differential systems, WAAS and EGNOS. • GLONASS capable	120 cm	15 cm	5-7 min
GS-LITE (500S only)	Ideal for tillage, broadacre spraying, and fertilizer applications. • Satellite delivery • GLONASS included	50 cm	30 cm	<3 min	✔
GS-LITE (700S, 600S, RS1, Viper 4+)	Ideal for tillage, broadacre spraying, and fertilizer applications. • Satellite delivery • GLONASS included	50 cm	15 cm	<5 min		✔
Satellite GS (500S only)	Utilizes premium correction data delivery to provide solutions with high accuracy and quick re-convergence in areas with loss of correction stream. • Corrections delivered via satellite direct to end user • No base station infrastructure required, simplifying equipment needs	8 cm	4 cm	<18 min		✔
Satellite GS (600S, RS1, Viper 4+)	Utilizes premium correction data delivery to provide solutions with high accuracy and quick re-convergence in areas with loss of correction stream. • Corrections delivered via satellite direct to end user • No base station infrastructure required, simplifying equipment needs	5 cm	4 cm	<30 min	✔	✔
Satellite GS-PRO (700S and RS1)	Utilizes premium correction data delivery to provide solutions with high accuracy and quick re-convergence in areas with loss of correction stream. • Corrections delivered via satellite direct to end user • No base station infrastructure required, simplifying equipment needs	3 cm	2 cm	<18 min	✔	✔
Slingshot RTK (700S, 600S, RS1, Viper 4+)	The most accurate, GNSS correction source available from Raven. • Sub-inch accuracy and repeatability and faster convergence times • Base station or CORS network required	2.5 cm	2.5 cm	<5 min	✔
RTK-L (700S and RS1)	Receiver can maintain centimeter-level positioning accuracy for outages in RTK correction messages (i.e. loss of cellular or radio connection). • Provides RTK level accuracy for up to 20 minutes of correction outage • Operates seamlessly in the background	--	--	<30 min	✔	✔
RTK PRO (RS1 only)	Unlocks unlimited RTK assistance, maintaining centimeter-level accuracy for even longer RTK correction outages and downtimes. Uses corrections from GPS, GLONASS, Galileo and BeiDou constellations to provide highly accurate and reliable positioning	--	--	<30 min		✔

Raven Industries, Inc.
205 East 6th Street
Sioux Falls, South Dakota, 57104

 

[dodge man]

This stuff isn’t cheap to subscribe to either. In Illinois the ag subscription from Trimble is something like $1850 a year. When I was still working the surveying side was called VRS, and as I recall it was less than the $1850 and we had multiple offices so that cost was spread out. Some states offer this for free but I don’t know if ag applications can use it or not. I know Iowa had free VRS for surveyors.