Unmanned aerial vehicles, commonly known as drones, are becoming increasingly popular tools for recording and monitoring farm operations. Here is Arable Farming’s 10-point guide to buying, using and staying legal with a drone. Jane Carley reports.
Drones can be used for a variety of mapping, imaging and surveying operations.
A common function is to study the crop in detail without extensive crop walking. Assessment of crop height and density allows evaluation of crops for uniformity and yield potential.
High-resolution plant count maps can provide early information on plant size by individual plant, row, plot or field, and can help to identify establishment issues such as planter skips. Yield potential can be estimated at early growth stages.
Crop coverage (canopy cover) in later growth stages can be reported as a coverage percentage, providing a base for crop productivity measurements. These measurements can be used alongside yield forecast models to give an understanding of expected output.
Comparing crops throughout the season to assess their progress and help determine contributory factors to yield success such as weather conditions, weed pressure or nutrition. In trial systems comparison at plot of sub-plot levels allows treatments and varieties to be evaluated.
Mapping and quantifying areas of weeds, disease and crop stress, allowing targeted control strategies.
Monitoring the progress of wheeling systems in controlled traffic regimes and studying machinery at work.
Identifying areas of concern on large farms for further investigation by crop walking.
Basic photography and recording of crops, machinery and farming activities.
Images captured by cameras on the drone are uploaded to a processing software package or processing service and are stitched together to produce maps which are ‘georeferenced’, i.e. contain data which positions them on the earth’s surface.
Once the georeferenced map has been produced it can have additional image-processing algorithms run on it such as Enhanced Normalised Difference Vegetation Index (ENDVI), which can highlight plant vigour and/or disease.
This data can be input into agronomic software which in turn produces variable rate prescription maps to control machinery such as sprayers, spreaders and drills.
Mapping software can also be used to add other data sources, so historic data such as soil samples can be added.
Drones are aircraft, thus subject to Civil Aviation Authority (CAA) regulations, specifically the CAP 393 Air Navigation Order.
It is now a criminal offence to contravene this legislation and any incidents will be investigated/prosecuted by the police.
The collection of images of identifiable individuals, even inadvertently, is subject to the Data Protection Act.
Operators need a Permission for Aerial Work (PFAW) from the CAA if the flight is for the purposes of aerial work and if ‘valuable consideration’ is given. This does not have to be financial compensation, the CAA defines it as being ‘better off’ which would include using the images taken to improve yield by tackling weed problems, for example.
This would also apply to an employee using a drone in the course of their employment.
The CAA also requires that pilots demonstrate a level of skill when they register their aircraft, achieved via a recognised qualification.
This qualification consists of a theory exam (ground exam) and flight test. The aim is to show the pilot is knowledgeable about their own aircraft and how they can use it in UK airspace, and this includes preparation of an operations manual on which the flight test is based.
A full list of ‘National Qualified Entities’ offering training and certification is available on the CAA website.
Drones can also be used to record machinery operations and monitor fixed wheelings in controlled traffic systems
Many agronomists are looking to add drone services to their portfolio.
BASIS has developed an introduction to basic aspects of the agricultural sector designed for professional operators of Unmanned Aerial Systems (UAS, drones).
The BASIS agricultural awareness for the UAS industry module is a stand-alone course providing candidates with a level of understanding and knowledge appropriate for their work in the agricultural industry.
BASIS is also developing a national register of UAS operators for the agricultural industry.
Members will need to apply with proof of qualifications for the category of aircraft intended for use for agricultural surveillance along with evidence of third-party UAS insurance.
BASIS is also developing a UAS Special Interest Group code of conduct and a CPD process for drones, plus a platform for members of the register to interact.
A number of drone suppliers will also offer ‘service flights’ which include production and analysis of images, although specialist interpretation of the images via an agronomist may also be required.
Drone contractors are also becoming increasingly common, although many have most experience in the surveying and aerial filming markets. It is important to check whether their equipment and services can produce useful data.
There are a few companies specialising in agriculture, offering processing and analysis packages, which can be purchased by the hectare.
In all cases, it is worth checking anyone offering drone services has the required Permission for Aerial Work (PFAW) and insurance.
Budget about £1,200 for an entry-level, multi-rotor machine with camera to take still photographs of crops and machinery. Training adds another £1,500 plus £150 per annum for the PFAW. Insurance costs are about £600 per year. Contractors aiming to offer a range of analysis services would be looking at £15,000 for a full package of a fixed wing aircraft and cameras plus analysis software and support.
The generic term is drone; machines are further defined by their type: multirotor (tricopter, quadcopter, hexacopter, octocopter depending on how many propellers) or fixed wing aircraft, which most closely resemble a model aeroplane.
The size of the UAV will generally dictate the camera payload. Most individuals start off with a small quadcopter capable of carrying a compact camera or video camera.
Larger octocopters and hexacopters can carry more powerful cameras or multi-function sensors.
A number of drones on the market can be fitted with NIR (near infra-red) cameras which use bands of the light spectrum not visible to the human eye to produce imagery for reflectance mapping which can indicate the health of the crop and identify weed areas in fields, e.g. black-grass.
Other cameras can be added, such as Red Edge systems which measure light in a particular band of the IR spectrum. Red Edge shows how well a plant is photosynthesising by measuring chlorophyll.
Control methods vary and include traditional transmitters, tablet and laptop control. The type of filming required will dictate the control method employed.
Maximum flying height is 120 metres above the surface without additional permission.
Minimum visibility is 5km.
Maximum distance from the operator is 500m, and a visual line of sight must be maintained to avoid collisions.
UAVs cannot be flown at night without special permission.
Permission must be obtained from the owner of the take-off point.
UAVs cannot be flown within 50m of structures, vehicles or vessels which are not under the control of the person in charge of the aircraft.
They must not be flown within 50m of people (there are exceptions relating to the operator during take-off and landing).
Flights must not go within 150m of ‘congested areas’, such as towns, cities and settlements or an‘organised open-air assembly’ of more than 1,000 people, such as an agricultural show or demonstration, without permission.
There are specialist UAV insurance companies able to provide cover for UAV operations. As a bare minimum, the CAA recommends company or individual should have public liability insurance. Some insurance companies will not cover UAV use in high-risk areas though, so do check this beforehand.
Harper Adams University hosts a special interest group for drones as part of the National Centre for Precision Farming
It has also published an Unmanned Aerial Systems Code of Conduct for operators
The CAA’s website has detailed information about legislation relating to drones:
has links plus a list of NQEs for training
www.basis-reg.com for information on BASIS training and the register of UAS operators.