Precision agriculture technology: GNSS guidance, auto-steering and data
Key takeaways
- Precision agriculture manages variation within fields instead of treating every hectare the same.
- GNSS guidance and auto-steering are usually the first step because they pay back through reduced overlap and operator fatigue.
- RTK corrections give repeatable 2–3 cm passes; SBAS-level guidance is cheaper but drifts between passes and seasons.
- Sensors and variable rate technology only add value when the data is cleaned, mapped and acted on.
- Adopt in stages, starting with guidance, then section control, then data-driven prescriptions.
What is precision agriculture?
Precision agriculture is the use of positioning, sensing and data to apply the right input, in the right place, at the right time. Instead of treating a field as one uniform unit, precision ag recognises that soil, moisture and yield vary from metre to metre and manages that variation.
The term covers a wide set of precision agriculture technology: GNSS (global navigation satellite system) receivers on tractors, automatic steering, sprayer section control, variable rate application, yield monitors, crop and soil sensors, and the precision agriculture software that ties them together. Smart farming and precision farming agriculture are often used as near-synonyms, although smart farming usually also includes connectivity and automation beyond the field.
For dealers and farm contractors, the practical question is which tools to adopt first and what accuracy each one needs.
How has technology changed farming?
Technology in agriculture has shifted the main constraint from machine power to information. Mechanisation made it possible to farm more land with fewer people; positioning and data now make it possible to farm that land more precisely.
- Satellite positioning made it possible to record exactly where a machine has been, which is the basis of guidance, mapping and section control.
- Automatic steering took over the repetitive task of driving straight lines, letting operators focus on the implement.
- Sensors and yield monitors turned harvests and field passes into maps rather than single totals.
- Connectivity moved data from the cab to the office, enabling planning and record keeping across seasons.
These agricultural advancements explain why modern farming relies as much on the console as on the engine. New farming technology is still evolving quickly, but the foundation remains accurate position.
Core precision agriculture technologies compared
Most precision farming systems combine a few core building blocks. The table summarises what each one does and the positioning accuracy it typically needs.
| Technology | What it does | Typical position accuracy needed |
|---|---|---|
| Lightbar or screen guidance | Shows the driver how far off-line the tractor is | Sub-metre to decimetre |
| Auto-steering | Steers the tractor along guidance lines automatically | Decimetre (SBAS) to 2–3 cm (RTK) |
| Section control | Switches sprayer or planter sections off over covered ground | Decimetre or better |
| Variable rate technology (VRT) | Changes seed, fertiliser or spray rates by zone | Sub-metre to decimetre |
| Yield monitoring | Records harvested quantity by location | Sub-metre |
| Controlled traffic, strip-till, bed forming | Keeps wheels and rows in the same place every season | 2–3 cm, repeatable (RTK) |
Variable rate technology is where precision farming techniques start to change input use directly, but it depends on good maps, which in turn depend on accurate positioning and clean data.
GPS in precision agriculture: which accuracy do you need?
GPS agriculture systems range from free satellite-based corrections to RTK with centimetre repeatability; the right choice depends on the operation. The key measure for guidance is pass-to-pass accuracy, meaning how closely one pass matches the next within a short time window.
| Correction type | Typical pass-to-pass accuracy | Repeatable next season? | Good for |
|---|---|---|---|
| Uncorrected or SBAS | Roughly 15–30 cm | No | Broadacre spraying, spreading, tillage |
| Satellite-delivered precise corrections | Roughly 5–10 cm | Partly | Larger arable farms without a base station |
| RTK (base station or network) | About 2–3 cm | Yes | Planting, strip-till, row crops, controlled traffic |
Figures are typical and depend on receiver, environment and correction quality. RTK (real-time kinematic) uses a nearby base station or a CORS network, as explained in what is RTK GPS. For a deeper look at guidance options, see tractor GPS guidance: lightbar vs auto-steer.
Precision agriculture sensors and their limitations
Precision agriculture sensors measure field and crop variation so that inputs can be matched to it. They are powerful, but each type has blind spots that users should understand.
- Soil sensors – electrical conductivity (EC) mapping indicates texture and moisture differences; probes measure moisture or nutrients at points.
- Crop canopy sensors – optical sensors calculate vegetation indices such as NDVI (normalised difference vegetation index) to estimate crop vigour.
- Remote sensing – satellite and drone imagery map variation across whole farms.
- Machine sensors – yield monitors, flow meters and implement sensors log what the machine actually did.
What are the limitations of agriculture sensors? Most measure an indicator, not the cause: low NDVI might be nitrogen, water or disease. Sensors need calibration, imagery is affected by cloud and sun angle, and yield monitors need regular calibration against weighed loads. Ground truth checks remain essential.
Precision agriculture software and data flow
Precision agriculture software turns positions and sensor readings into decisions and records. Without it, data stays on a USB stick in the cab.
A typical data flow looks like this: field boundaries and guidance lines are created once and shared between machines; operations are logged as coverage maps; yield and sensor data are combined into management zones; prescription maps are written for variable rate application; and as-applied maps close the loop. The ISO 11783 (ISOBUS) standard helps tractors, implements and terminals from different makers exchange data.
When choosing precision farming software, check that it imports and exports common formats, keeps data owned by the farm, and works offline in areas with poor mobile coverage.
Benefits and cons of precision agriculture
The benefits of precision agriculture come mainly from less overlap, better timing and better records. The cons are upfront cost, the learning curve and data management effort.
Benefits
- Reduced overlap and skips, saving seed, fertiliser, chemicals and fuel.
- Less operator fatigue and the ability to work in dust, darkness or long shifts.
- Consistent rows and tramlines that make later operations easier.
- Field records that support traceability and sustainable farming technology goals.
Cons of precision agriculture
- Investment in hardware, corrections and sometimes subscriptions.
- Training needs for operators and managers.
- Compatibility issues between brands and older machines.
- Data that is collected but never analysed adds cost without benefit.
Savings vary widely with farm size, crop and current practice, so estimate them for your own operation. Our auto-steer savings calculator gives a starting point.
How to adopt precision farming technology in stages
Staged adoption keeps risk low and lets each step pay for the next. A common sequence for a farm or a dealer advising customers is:
- Map fields. Record boundaries and obstacles with GNSS.
- Add guidance and auto-steer. Fit an auto-steering kit to the tractor used most, with RTK if row crops or controlled traffic are planned.
- Add section control. Reduce overlap on sprayers and planters.
- Collect yield and sensor data. Build a few seasons of maps.
- Introduce variable rate. Create zones and prescriptions once data is reliable.
- Review annually. Compare input use and yields, and adjust.
See our guide to tractor auto-steering systems for installation and calibration of step two.
Precision ag equipment from Mars Geosystems
Mars Geosystems supplies GNSS guidance hardware for farms, contractors and agricultural dealers. The SAgro200 and SAgro180 auto-steering kits deliver ±2.5 cm pass-to-pass accuracy with RTK and suit mainstream tractor brands, while the S20 GNSS smart antenna (1408 channels, IP67) provides vehicle positioning for guidance and machine control. Dealers can order a single demo unit or OEM-branded kits; request a quote with your tractor models and correction source.
Frequently asked questions
What is precision agriculture in simple words?
Precision agriculture means farming each part of a field according to its needs rather than treating the whole field the same. It uses satellite positioning, sensors and software to steer machines accurately, apply seed and fertiliser where they are needed, and record what happened where. The result is less waste and better information for decisions.
What equipment is used in precision agriculture?
Common precision agriculture equipment includes GNSS receivers and smart antennas, guidance displays, auto-steering kits, sprayer and planter section control, variable rate controllers, yield monitors, soil and crop sensors, drones for imagery, and farm management software. Most farms start with a GNSS receiver and auto-steering, then add other tools as data and experience build.
How accurate is GPS for farming?
It depends on corrections. Uncorrected or SBAS-corrected GNSS typically gives around 15–30 cm pass-to-pass accuracy, which suits spraying and spreading. Satellite-delivered precise corrections typically reach about 5–10 cm. RTK corrections from a base station or network give about 2–3 cm and repeat from season to season, which planting and controlled traffic require.
What are the disadvantages of precision agriculture?
The main disadvantages are upfront cost, the need for training, compatibility problems between different brands and older tractors, and the time needed to manage data. Some tools, such as variable rate application, only pay off after several seasons of reliable data. Poor mobile coverage can also limit network RTK and cloud-based software in remote areas.
Is auto-steering worth it on a small farm?
Often yes, if the tractor works many hours a year or the farm grows row crops. Auto-steering reduces overlap, operator fatigue and skipped strips, and entry-level kits have made it more affordable. The payback depends on hectares worked, input costs and labour, so estimate savings for your own operation before buying.
What is variable rate technology in agriculture?
Variable rate technology (VRT) automatically changes the application rate of seed, fertiliser, lime or chemicals as a machine moves through a field. It follows a prescription map built from soil tests, yield maps or crop sensors, or responds to on-the-go sensors. Accurate positioning ensures each rate is applied to the correct zone.
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