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Phone vs light bar vs autosteer vs RTK: tractor GPS options and costs

Short answer

There are four levels of tractor GPS. A phone app costs roughly $30–$100 a year and is accurate to a metre or two on newer dual-frequency iPhones, up to about 5 m on older ones. A light bar costs roughly $1,500–$2,000 and is steadier than a phone. Autosteer with RTK costs several thousand to over $10,000 and holds the line to within a few centimetres. Pick the cheapest one that's accurate enough for your narrowest job.

Updated · Oran Dynamics

Every price below has a source and a date; dealer prices vary.

The four levels at a glance

LevelWhat you getAccuracyTypical cost (read 20 Oct 2026)
Phone appGuidance lines and a coverage map on a phone or tablet; you steerTypically 0.5–0.7 m side-to-side on a dual-frequency iPhone; up to ~5 m on older iPhonesAbout US$30–$100 a year. Ours is US$89 a year; rival iPhone apps list prices from $29.99 to $99.99 (App Store)
Light bar / guidance displayA dedicated GPS receiver and display or LED bar; you steerBetter than a phone; depends on the receiver and correction signalTeeJet Matrix 430: $1,596 (dealer sale; $1,995 list)
Autosteer (assisted steering)A motor or hydraulic valve steers on the line; you turn on headlandsDecimetres on free signals; a few centimetres with RTKJohn Deere AutoTrac Universal 300 kit $1,695 plus receiver ($4,300) and display ($6,495 with AutoTrac); open-source AgOpenGPS kits from about £700 (DIY) to £2,950 (ready-built)
RTK correctionsCentimetre corrections for a receiverA few centimetresFree in some US states (state DOT networks); commercial services listed at about $50–$500 a month; John Deere's 1-year SF-RTK bundle costs $1,500 more than the SF1 receiver

Phone app

For: spreading, spraying, slurry, topping and rolling with wide implements; mapping and measuring fields; anyone who wants to try guidance without buying hardware. Not for: drilling, planting rows, strip-till or anything that needs centimetres. How ours works: how it works. Rivals: comparison.

Light bar

A roof-mounted receiver plus a display or LED bar. Better and steadier than a phone, with SBAS/WAAS-class signals, and many can take paid corrections for better accuracy. You still steer. A sensible step up if a phone isn't accurate enough but autosteer is more than you need.

Autosteer

The system steers the tractor along the line. It reduces fatigue and holds the line better than a person, and it's what most row-crop and controlled-traffic farms run. Costs vary widely by brand, display and correction level: a John Deere entry setup on the US government price list (steering kit + receiver + display) runs well over $10,000, while kits from newer makers and open-source AgOpenGPS builds are far cheaper. Farmers Weekly reported a UK-built AgOpenGPS kit at £2,950 (2024) and a DIY build at about £700 (2021).

RTK

RTK is a correction signal, not a type of display: a base station (yours, or a network's) corrects the receiver's position to within a few centimetres. It's what makes autosteer repeatable year to year. Some US states run free RTK networks; check your state DOT. Commercial services and OEM subscriptions cost more.

Features you only get with a terminal

Yield mapping, variable-rate and prescription maps, ISOBUS implement control, automatic section control, terrain (tilt) compensation and implement steering belong to dedicated terminals and receivers, and they're the main reason large arable farms buy one.

Which to choose

  • Narrowest job is spreading, spraying or topping on open ground: start with a phone app.
  • Phone not steady enough, but you'll still steer: a light bar.
  • Drilling, row crops, long days in the seat: autosteer with RTK.

Questions

It ranges from about £700 for a DIY open-source build to well over $10,000 for a brand-name system with display, receiver and RTK. A John Deere AutoTrac Universal 300 steering kit alone is $1,695 on the US government price list, before the receiver and display.

The receiver costs from a few hundred pounds for open-source builds to several thousand dollars (John Deere StarFire 7500, $4,300). Corrections are free on some state networks; commercial services cost tens to hundreds of dollars a month.

A phone app using the phone you already own. Tractor GPS – Field Guidance is US$89 a year after a 7-day free trial, accurate to a metre or two on newer dual-frequency iPhones, up to about 5 m on older ones.

A GPS guidance display, often a row of LEDs, that shows which way to steer to stay on the line. You steer; it guides.

For row crops and long hours, usually yes. For a few hundred acres of grassland spreading and spraying, a phone app or light bar is often enough.

Sources (read 20 October 2026)

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