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Home › Industries and applications › Agriculture › Spray windows and drift
A self propelled sprayer working a field with booms extended
Spray windows and drift

The spray window opens on a wind speed.
The record has to prove it.

Compact ultrasonic wind measurement for spray decisions, mounted on the sprayer or at the field boundary, so the decision and the record it creates come from the field rather than from a forecast.

0.5 kg
GMX200 compact station weight
0
Moving parts to service or clean
2%
RMSE wind speed at 12 m/s on WindSonic
6
UKAS-accredited calibration parameters

The decision is made at the field and defended later

Whether an application can go ahead is a wind speed and direction question, answered at the field gate, often against a weather window that has been closing all morning.

The same decision is then written into a record that is read much later by somebody who was not there. Assurance schemes, product stewardship requirements and neighbour complaints all reach back into that record, and a forecast figure is a weaker answer than a measurement.

Drift is the reason. Wind speed decides whether the spray reaches the target, and direction decides who else it reaches, which turns a routine operation into a boundary dispute if the conditions were misjudged.

Farm sensing map

One holding. Multiple measurement points.

A farm is not one measurement environment.

Wind at the field boundary can be different from the regional forecast. Conditions inside a grain store are different from those outside it. Water levels change with use and rainfall. Machinery develops wear while the rest of the operation continues around it.

Explore the measurement points across a working agricultural holding and see where environmental, level, condition and position sensing can support the operation.

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Need sprayer mounting, boundary masts or calibration certification?Compact sensing, vehicle and mast mounting, output formats and traceable calibration. Direct from our engineering team.

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Measured at the field, not at the nearest station

Wind at a field boundary is not the same as wind at a regional station, and the difference is largest exactly when it matters. Shelter from hedges, buildings and topography changes both speed and direction across a single holding.

Mounting on the sprayer puts the measurement at the operation rather than near it, and it travels between fields without anything being moved. Mounting at a boundary puts it at the sensitive edge, which is usually where a complaint originates.

Direction carries as much weight as speed. An application at the same wind speed is a different proposition depending on whether the sensitive boundary is upwind or downwind, and the record needs both.

Whichever position is chosen, the instrument spends its life in dust, spray and wash-down, so anything with a rotating element becomes a cleaning task before it becomes a measurement problem.

The measurement travels with the operation

A sprayer moves between fields and between holdings, and a fixed mast measures one of them. Mounting the sensor on the machine means the reading describes the field being treated rather than the field the mast is in.

Ultrasonic measurement suits the position because there is nothing to clean or to seize. GMX200 provides wind-only measurement at 0.5 kg, and WindSonic measures 0 to 60 or 0 to 75 m/s and publishes its accuracy across the full measuring range.

The reading from the field being treated

View WindSonic

Where the complaint comes from

A sensitive boundary is a fixed location, and a fixed measurement there answers the question a complaint asks: what was the wind doing at this edge at this time.

A compact station at the boundary also carries the rest of the record. MaxiMet brings wind, temperature, humidity, pressure, solar radiation and rainfall into one unit on one cable, which covers the application conditions and the wider agronomic record together.

One unit, the whole condition record

View MaxiMet

An application record is an audited document

Assurance schemes and product stewardship both require application records, and those records are inspected. A conditions entry taken from a forecast is weaker than one taken from an instrument, and weaker still if the instrument cannot be identified.

Traceable calibration is what closes that. An instrument on an interval turns the conditions entry into evidence rather than an estimate, which matters most in the cases where it is challenged.

Labcal is an independent UKAS-accredited laboratory operating to ISO/IEC 17025:2017, calibrating equipment from any manufacturer, which suits a holding with instruments bought at different times.

What a spray operation measures

Wind measurement on the machine and at the boundary, with the wider agronomic record from the same installation.

Wind measurement

Gill WindSonic ultrasonic anemometers
Sprayer and mast

WindSonic

Lightweight 2-axis ultrasonic anemometer

Lightweight ultrasonic measurement for sprayer booms, cab mounts and field masts, with nothing to clean or seize.

Range : WindSonic 60 measures 0 to 60 m/s; WindSonic 75 to 0 to 75 m/s
Accuracy : Full-range accuracy published for WindSonic 60 and 75
Options : WindSonic M is heated aluminium, operating to -40 degrees C

View WindSonic

Gill WindUltra compact ultrasonic anemometer
Mobile

WindUltra

Compact 2-axis ultrasonic anemometer

A compact 2-axis anemometer for vehicle and mobile mounting, sealed and rated IP66, IP68 and IP69K for wash-down.

Build : Compact and lightweight, rated IP66, IP68 and IP69K
Use : UAV, USV, portable and mobile installations
Power : Low-power operation for battery and solar deployments

View WindUltra

Gill WindObserver ultrasonic anemometers
Exposed

WindObserver

Heated 316 stainless open-head 2-axis anemometer

Heated 316 stainless where a boundary mast has to keep reporting through every season on an exposed holding.

Range : WindObserver 90 measures 0 to 90 m/s; 75 measures 0 to 75 m/s
Build : 316 stainless steel, IP66, heated, icing tested to MIL-STD-810F
Direction : 0 to 360 degrees with no dead band

View WindObserver

Conditions and record

Gill MaxiMet compact weather stations
Field station

MaxiMet

All-in-one weather station, no moving parts

Wind, temperature, humidity, pressure, solar radiation and rainfall from one unit on one cable at the boundary or the yard.

Full station : GMX551 carries wind, temperature, humidity, pressure, solar and rainfall
Compact : GMX200 is 0.5 kg and measures wind only
Rainfall : GMX600 and GMX603 carry optical rainfall measurement

View MaxiMet

Gill TruMet PW100 optical rain gauge
Rainfall

TruMet PW100

Infrared optical rain gauge

Optical rainfall measurement with no tipping mechanism to block with dust, chaff or insects.

Range : 0 to 200 mm/hr, accuracy 5 percent, resolution 0.1 mm
Output : One pulse per 0.1 mm, replicating a tipping bucket
Build : No moving mechanism to block or seize

View TruMet PW100

Gill MetConnect weather stations
Reference

MetConnect

Separable sensors for WMO-compliant siting

Separable sensors where the holding keeps a reference record at defined heights alongside the operational measurement.

Siting : Separable sensors mounted at the heights the standard expects
Inputs : Accepts third-party, analogue and Pt100 inputs
Models : MetConnect One and MetConnect THP

View MetConnect

Not sure which product fits this application?Tell us where it will be installed, what it has to survive and the system the data has to reach. Our team will narrow the range down with you.

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Where spray window measurement does the work

Arable spraying

Field applications

Wind speed and direction at the field being treated, recorded against the application.

Sensitive boundaries

Watercourses and dwellings

Fixed measurement at the edge that a complaint would be made about.

Contract spraying

Multiple holdings

Sprayer-mounted measurement that travels between customers and records each job.

Assurance schemes

Inspected records

Conditions entries supported by an identifiable, calibrated instrument.

Orchards and vines

Directed application

Operations where drift behaviour and canopy shelter both change with direction.

Agronomy

Window planning

A conditions record that shows when the window actually existed across a season.

UKAS-accredited calibration for six measurement parameters

Labcal is an independent UKAS-accredited calibration laboratory, Lab 0625, operating to ISO/IEC 17025:2017. It provides calibration across gas and air flow, air velocity, liquid flow, pressure, temperature and humidity.

For a holding carrying anemometers, thermal probes, pressure instruments, thermometers, temperature and humidity probes and data loggers, one accredited laboratory keeps instruments bought at different times on a single traceable schedule.

01 · Gas and air flow

Gas meters · Mass flow controllers · Dispensing systems

02 · Air velocity

Anemometers · Pitot tubes · Thermal probes

03 · Liquid flow

Flow meters and sensors · Process control equipment

04 · Pressure

Gauges · Transducers · Manometers · Transmitters

05 · Temperature

Thermometers · Probes · Thermocouples · Data loggers

06 · Humidity

Hygrometers · Probes · Transmitters

One laboratory. Six UKAS-accredited parameters.Equipment from any manufacturer.

Explore Calibration Services

Getting the reading into the job record

A spray decision is taken in the cab and recorded in a farm management system, so the measurement has to reach both a display and a record rather than one or the other.

Gill supports environmental monitoring, industrial sensing, embedded electronics and systems integration, so machinery manufacturers, dealers and holdings can bring measurement into cab displays, controllers and farm software.

Whether the requirement is CAN into a machine network, a serial string into a display, SDI-12 into a logger, or analogue into an existing channel, Gill engineers can support integration from specification through commissioning.

Outputs and options

  • CAN & RS232 : Machine networks and cab displays
  • SDI-12 : Field loggers and telemetry
  • Modbus RTU : Farm and site systems
  • 4-20 mA & 0-10 V : Existing analogue channels

What the specification looks like in practice

01

Measured at the field, not near it

Wind at a boundary differs from a regional station most when shelter and topography matter, which is exactly when the decision is marginal.

02

Nothing to clean or seize

Ultrasonic measurement has no rotating element to foul with dust, chaff or spray residue.

03

Light enough for the machine

GMX200 measures wind at 0.5 kg, which decides whether the sensor goes on the sprayer or stays in the yard.

04

Direction as well as speed

Whether a sensitive boundary is upwind or downwind changes the decision at the same wind speed.

05

Sealed for wash-down

WindUltra is rated IP66, IP68 and IP69K, which suits a machine that is pressure washed.

06

Evidence when the record is inspected

Independent UKAS-accredited calibration across six parameters, for equipment from any manufacturer.

Ready to specify?Talk through approvals, mounting, power and integration with our team before the specification is fixed.

Discuss your requirements

Questions about spray windows and drift

Spray conditions and records

They answer different questions. A sprayer-mounted sensor describes the field being treated and travels between them. A boundary mast describes the sensitive edge that a complaint would concern.

Many holdings end up with both, because the operational decision and the defensive record are not quite the same thing.

Gill engineering insightIf only one is affordable, the sprayer mount usually does more work, because it covers every field rather than one.

Because there is nothing to clean or to seize. A sprayer lives in dust, chaff and spray residue and is pressure washed regularly, and a rotating element becomes a maintenance task before it becomes a measurement problem.

Accurate enough to support the decision and identifiable enough to support the record. WindSonic 60 and 75 have published accuracy across the full measuring range, not just at a single test speed.

Scheme requirements vary, but a conditions entry supported by an identifiable instrument on a traceable calibration interval is considerably stronger than one taken from a forecast.

Generally yes. The sensors provide CAN, serial and analogue outputs, and the engineering team can advise on the interface a particular machine or display expects.

Yes. Labcal is an independent UKAS-accredited calibration laboratory, Lab 0625, operating to ISO/IEC 17025:2017, calibrating equipment from any manufacturer across gas and air flow, air velocity, liquid flow, pressure, temperature and humidity.

Speak to our team

Tell us what you need to measure, where and under what conditions. We’ll help you work out the appropriate approach.

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