- Drones, remotely piloted aircraft systems or unmanned aerial systems, have evolved rapidly in recent years from military and consumer hobbyist use into business applications across many industry sectors.
- The immediate industry beneficiaries are in the surveying, civil construction, agricultural, environmental, mining, cinematography, capital asset management and emergency services’ sectors.
- Unmanned aerial systems can gather more detailed and complete information far more quickly, more cost effectively than satellites, manned aircraft or conventional ground survey methods.
- Drones equipped with very high resolution optical cameras, multispectral or infrared lenses and high definition video capture thousands of images in a single flight to produce 2D maps, 3D models or thermal images. The image processing software then provides detailed technical information with survey standard quantification for decision making.
- Agricultural drones provide farmers with real-time and near real-time information about soils, plant health, growth rates, fertiliser requirements, weeds, pests and frost or storm damage.
Introduction and Background
High technology, unmanned aerial systems or drones are increasingly moving from military to commercial applications and bringing with them changes that are revolutionising a broad range of industry sectors. Drones equipped with digital imaging equipment and other sophisticate sensing technology are leading to major procedural changes. Surveying, construction, mining, environmental monitoring and agriculture are just a sample of the of the industries benefiting from the accurate, up-to-the-minute and economically affordable information drones can provide. In Australia, the relatively uncrowded airspace and a mature regulatory system provides an environment where entrepreneurial innovation can realistically aspire to produce world leading solutions. In this two-part FDI Associate Paper, Mr Geoff Trowbridge of ScientificAerospace firstly discusses the general, high technology innovations drones are bringing to a wide range of applications and secondly the specific benefits drones can bring to agricultural production.
The migration of drones, remotely piloted aircraft systems (RPAS) or unmanned aerial systems (UAS) from military use into business applications and consumer hobbyist usage has grown enormously in recent years.
Physical aspects of drone design such as aerodynamics, structures, controls, propulsion, weight and balance are all well-known.
It is advances in materials, miniaturisation of avionics, intelligence of sensors and ground controls that have created a new, ground-breaking class of products. Many of the miniaturised systems have evolved from the technology developed for smart phones; most notably, the lithium batteries that nearly all commercial drones use to power their small electric motors.
Business analysis from PricewaterhouseCoopers, Goldman Sachs, and Forbes are forecasting this phenomenon will become a US$127bn business over wide industry sectors in the very near future following the pattern of Google, Amazon, Twitter, AirBnB and Uber. They are set to become a part of the digital technology tool kit of many professions needing an assessment of current conditions of valuable assets in the built and natural environments.
Figure 1. An example of a modern industrial drone in its flight and transportation configurations. Source: The Author.
Benefits and Advantages
Drones can currently provide immediate benefits in surveying, civil construction, agriculture, mining, cinematography, capital asset management, environmental and emergency services sectors. What they all have in common is that UAS can gather more detailed and complete information far more quickly and cost effectively with more safety than conventional ground survey, manned aircraft or satellite methods.
Compared to the cost of owning or hiring satellite transponders, helicopters, using scaffolding or even abseiling, the costs of operating drones is tiny. They can be launched almost anywhere, go into hazardous environments carrying ultra-high definition still, video, infrared and multispectral cameras, or a variety of other sensors. They can zoom in to look at minute detail in otherwise inaccessible, difficult or dangerous locations such as oil and gas flare tips, multistorey buildings and bridges. Being airborne and relatively quiet, they do not compress soil, crush vegetation or disturb animals.
By flying at low altitude and getting in close to subjects to take multitudes of photographs, they can gather large amounts of data in a process called photogrammetry. The photographs and data gathered can then be processed to produce technical information such as 3D maps and thermal images for immediate decision making in construction, infrastructure maintenance, agriculture, mining, transport, emergency services and many other applications.
About the Airframes
There are two main classes of industrial drones: multirotor and fixed wing. Multi-rotors are ideally suited to infrastructure inspection and precision agriculture but have a short flight time of 25-30mins per battery. Multi-rotors are commonly made of ultra-violet resistant plastic, carbon fibre or 3D printed high quality nylon. Fixed wing drones are usually made of heavy duty foam and may have a kevlar skin. Fixed wing drones have a much longer flight duration than multi-rotors of up to and beyond three hours per battery and are more suited to broad acre farming, mining, road and rail construction pipeline and power line inspection. Either type may fly at up to 60 kmh. The avionics, cameras, lenses, sensors and ground controls of both are very similar and often interchangeable.
What’s in Them?
Almost anything found on a conventional passenger aircraft has an equivalent in a commercial UAS, including flight controls, air speed system, global navigation satellite system, auto pilot, motion tracking, inertial systems, magnetic compass, radio communications, collision avoidance systems, flight data recording, cameras and laser radars (Lidars). These tiny, lightweight components that operate at low voltages with low power consumption may be sourced on-line from manufacturers all over the world.
Figure 2. Multi-spectrum vegetation analysis ideal for the agriculture and viticulture industries, as crop health can be monitored more precisely and regularly than with traditional methods. Source: Author.
A drone flying with a GPS on autopilot is monitoring and adjusting its location thousands of times per second with an accuracy a manual pilot cannot achieve. When fitted with a camera on a two or a three-axis pivoting mount, the same drone can acquire significantly superior quality aerial photos and video than a pilot can obtain.
The cameras used are typically high quality consumer or industrial cameras. They normally employ high resolution, low frame rate cameras (20+ Megapixel stills and 4K video at 24-30 frames per second) or lower resolution, higher frame rates (1080 pixels at up to 60 frames per second). For some applications, one person can control the camera while someone else flies the UAS. While surveyors and industrialists want centimetre accuracy, farmers and graziers are usually content with half-metre accuracy.
Ground Station transmitters are typically 10-15 channel, 2.4GHz transmitter and 5.8GHz video receiver. They use traditional radio control joysticks to pilot the drone and most come with a mobile tablet device with a touchscreen for flight planning and to view what the camera is seeing. Data is stored on board the aircraft and in a removeable 128GB memory card which is then processed separately.
About the Software
Software is used to control the aircraft, enable autonomous flights, integrate the aircraft systems, process flight information and analyse data after the flight. The nerve centre of a drone is the flight control system which processes inputs thousands of times a minute from a variety of sensors such as GPS, barometric pressure, airspeed, accelerometers magnetometer/compass and telemetry. This enables them to fly completely autonomously, to follow waypoint based missions, control cameras or sensors and assess wind conditions when coming in to land.
With a stable radio link between a base station on the ground and a GPS antenna on board the UAS, satellite navigation can be used to correct positioning data in real time and provide close to one-centimetre-level accuracy in UAS navigation and land surveying operations provided the radio link is not broken. If the link is broken, data may be lost and there is a high risk of unintended failure. UASs can lock on to global navigation systems from the USA, UK, China and Russia. They typically need a minimum of six satellites but normally use 23 for accurate navigation and photogrammetry.
Alternatively, the positioning information for objects may be corrected after the flight but not during it. Data in the aircraft can be combined with data from a base station or ground control points when the flight is completed. The processing traces back and forth through the data multiple times to give more comprehensive results with greater reliability and therefore accuracy. The UAS can also operate at greater range from the base station and still provide post flight, survey-grade results with aerial mapping.
Who Makes Them?
The major manufacturers of military drones include Lockheed Martin, BAE, Northrop Grumman, Boeing and General Atomics. The major manufacturers of commercial drones are DJI, Yuneec, Ascending Technology, AeroVironment, PrecisionHawk, SenseFly and Airware. The most common cameras in use are brands such as Sony, Panasonic and Canon.
In Australia, ScientificAerospace manufactures and supports the 4Scight quadrotor, and FarScight mapping drones. Both are genuine photogrammetric systems which capture and process aerial data with a minimum of ground control points and provide unparalleled accuracy; around 35 mm horizontally and 50 mm vertically.
The Regulatory Regime
The fact that most drones carry cameras does create aerial trespassing and privacy issues. Equally, public safety must be protected so the Civil Aviation Safety Authority make regulations to ensure they are not operated in a way that creates a hazard to another aircraft, person or property. Flying a small drone over 2kg requires that the operator be licenced, maintain the UAS within visual line-of-sight, below 120m AGL, at least 30m away from people and at least 5.5km from controlled aerodromes.
If flown in restricted or military areas subject to Notice to Airmen notices, a prior formal clearance must be obtained. They must not be flown over populous areas or where emergency operations are underway. Similar regulatory regimes exist in many other countries such as the Federal Aviation Administration in the United States, but Australia is a world leader in this area.
The full extent of the influence commercial drones will have on the business and industrial landscape is difficult to predict as the capability is still perhaps in its technological infancy. Nevertheless, the application of drone technologies in existing business processes is allowing companies from those industries to create new business and operating models. Formal industry analysis has identified agriculture as one of the most promising fields for UAS applications. The ability for farmers to make sound business decisions based upon real-time high quality data that is available at a reasonable cost is essential to a successful modern agricultural enterprise. UASs provide digital data that is difficult or impossible to obtain from the ground. Piloted aircraft with the precision of a UAS are very expensive. Satellite data can also be expensive and the collection intervals is often long and beyond the farmer’s control.
In Part Two of this Associate Paper, Mr Trowbridge will discuss some of the specific applications UAS are bringing to agricultural production.