An uninhabited aircraft is defined using the general terms UAV (unhabited aerial vehicle or unmanned aerial vehicle), ROA (remotely operated aircraft), and RPV (remotely piloted vehicle). A pilot is not carried by an unhabited aerial vehicle, but the power source, which provides dynamic lift and thrust based on aerodynamics, is controlled by autonomous navigation or remote control navigation.
Introduction
There has been a rapid growth globally in the acquisition and development of Unmanned Aerial Vehicles (UAVs). Approximately 80 countries have UAVs, of which fewer than a dozen operate systems that can be armed, according to the Ministry of Defence. The US General Accounting Office estimates the number of countries with UAVs has increased from approximately 41 in 2004 to at least 76 countries in 2012. Unmanned Aerial Vehicles (UAVs), commonly referred to as drones, are remotely piloted aircraft or systems. They range from simple hand-operated short-range systems to long endurance, high altitude systems that require an airstrip. UAVs have civil and commercial uses. There has been a rapid growth globally in the acquisition and development of Unmanned Aerial Vehicles (UAVs). Approximately 80 countries have UAVs, of which fewer than a dozen operate systems that can be armed, according to the Ministry of Defence. The US General Accounting Office estimates the number of countries with UAVs has increased from approximately 41 in 2004 to at least 76 countries in 2012. Unmanned Aerial Vehicles (UAVs), commonly referred to as drones, are remotely piloted aircraft or systems. They range from simple hand-operated short-range systems to long endurance, high altitude systems that require an airstrip. UAVs have civil and commercial uses.
More advanced UAVs used radio technology for guidance, allowing them to fly missions and return. They were constantly controlled by a human pilot, and were not capable of flying themselves. This made them much like todays RC model airplanes which many people fly as a hobby. It is interesting to note that the government considers all aircraft UAVs, if they are unmanned and used by a government or business. After the invention of the integrated circuit, engineers were able to build sophisticated UAVs, using electronic autopilots. It was at this stage of development that UAVs became widely used in military applications. UAVs could be deployed, fly themselves to a target location, and either attack the location with weapons, or survey it with cameras and other sensor equipment. Modern UAVs are controlled with both autopilots, and human controllers in ground stations. This allows them to fly long, uneventfully flights under their own control, and fly under the command of a human pilot during complicated phases of the mission.
Beginning of the UAV
American Lawrence and Sperry manufactured the first UAV in 1916. They developed a gyroscope to stabilize the body, as an autopilot aid. They called the aircraft the ‘aviation torpedo’ and they managed to fly the device to a distance which exceeded 30 miles. This device however was not considered for use during both World War I and II.
Figure 1
Development from this did not begin until the end of the 1950’s, taking advantage of the Vietnam War, with large scale research and development continuing into into the 1970’s.
After the Vietnam war, the U.S and Isreal began developing smaller and more cost effective UAV’s. These were small aircraft with adapted motorcycle engines, carrying video cameras and transmitting still images to the operation on ground location.
In the Gulf War of 1991, the USA used the UAV’s for military applications and from here on in the development of UAV became more and more rapid, until you reach the UAV’s of today, with highly technichal flight controllers used in combination of sensors suited for the purpose of flight. Alongside you will find today that there are capabilties of a continous video link from UAV to ground station.
Types of UAV
In general an aircraft is any flying vehicle with any configuration of fixed wing, rotary wing, a balloon or an airship. Any of these aircrafts have the potential of becoming UAV systems with the correct technology and control system. Therefor one of the ways classifying different types of UAV is by their type of aircraft configuration:
Fixed wing
Fixed wing are the most common types of UAV’s and are currently being used for wide range of applications. These can be of different sizes, from a small backpack Casper from Becker Avionics with a wing span of 2.5m to and Northrop Grumman Global Hawk with a wing span of 40m. The success of fixed wing UAV’s is largely down to their stability which require simpler systems to control, compared to other configurations. (Can be seen in figure 2).
Rotary wing
There have been a lot of development in rotary wing UAV’s in recent years. The manoeuvrability and the ability to maintain the aircraft hovering in one set point position is a big favourable factor. However even though there has been intense development within the flight controllers of these UAV’s, they are still very unstable. (Can be seen in figure 3).
Airship
A number of unmanned airship projects, both free-flying and tethered have been imitated to provide synergistic capabilities to those provided by unmanned aircraft, most notably extended persistence. There appears to be potential for mission applications including force protection, signal intelligence collection, communications relay and navigation enhancement. An airships most significant challenge appears to be its limited mobility. (Can be seen in figure 4).
Figure 2 Fixed wing UAV
Figure 3 Rotary win UAV
Figure 4 UAV Airship
Benefits
Unmanned Aerial Vehicles (UAVs) or Systems have a number of strengths and weaknesses compared to manned aircraft. UAVs help minimise the risk to aircrew operating in hostile territory and can be used for ‘dull, dirty and dangerous’ tasks. They can be more cost effective and provide a significant intelligence, surveillance and reconnaissance capability, whether that is ‘over the hill’ sight for soldiers on the ground or a persistent presence in the air which can help provide a more complex intelligence picture for commanders. This in term can help inhibit an enemy’s ability to move in secrecy. They are more expendable than manned aircraft, at least in terms of human life if not in cost.
Disadvantages
UAVs currently lack the flexibility and adaptability of manned aircraft and the more advanced systems require as heavy if not heavier crew requirement than manned aircraft. Depending on their capabilities they may not necessarily be more cost effective. A Ministry of Defence Joint Doctrine Note suggests ‘If current trends continue, it is likely that the cost of complex unmanned aircraft will increase to converge rapidly with those of manned aircraft.’2 The vast quantity of data provided by UAVs requires similar advances in automated data analysis to ensure the information collected is of use. They may also be vulnerable to failure and to data link interference. There are also restrictions on where they can operate, particularly in civilian airspace.
Overall Uses in Depth
In the future, small UAV’s will become part of homeland (border) security. In lots of countries, like India, Pakistan, and the USA, their homeland security departments already have plans to deploy UAV’s to watch coastal areas and protect major oil and gas pipelines. The use of small UAV’s in the recent war in Iraq and Afghanistan has shown many advantages. These days, small UAV’s are tremendously flexible devices, which can be used for a variety of civil purposes. For example, they can be used to provide entertaining videotaped scenes to movie-makers, news reporters and the tourism industry; to search for and rescue people in perilous locations or circumstances (collapses, spills and fires); and to monitor or deliever mail to important installations in either highly sensitive locations (borders, ports and powerplants) or remote or unhabitable places (polar zones, deserts and off-shore oil rigs). Currently researchers are trying to make UAV’s for farmers, where they can use them to check stock levels and welfare. Australia are already using remotely managed UAVs to take high resolution images of crops to predict protein levels. This saves a lot of time and money for the farmers because they get feedback about their crops, without having to travel there to see it for themselves. Here is a list of potential areas where UAV’s may be used:
Aerial photography
Agriculture
Coastguard
Conservation
Customs and Excise
Electricity companies
Environment agencies
Fire Services and Forestry
Fisheries
Gas and oil supply companies
Information services
Local authorities
Meteorological services
Traffic agencies
Navy
Army
Air Force
Flight Controllers
Flight controllers are the brains behind the ‘Autonomous’ driving of UAV’s. They are becoming increasingly more technology smart, with the average hobbyist flight controller having the
Capabilities of GPS, Gyroscopes, Accelerometers, Barometers, Magnetometer, Outputs for Gimbal control and FPV (First person viewing), along with the outputs of controlling motors.
Figure 5 Multiwii Pro Flight Controller
Hobbyist flight controllers come preloaded with ‘Open-source code’. Code that is readily available for no charge, for the purpose of giving users the ability to study, use and develop and progress the code, but keeping the deserved creditability. The GPS (Global Positioning System) on the device can be used for many uses, for in depth monitoring of the UAV, to controlling the path that it takes by setting ‘waypoints’, a set of co-ordinates that identify a point in a physical space. The advantage with using this technology is providing that there is a presence of signal at all times, there will be precise command to give the UAV. So for fragile circumstances such as war or a natural disaster, you can send in a UAV to survey precise locations. Another example of GPS use is if a UAV goes down, you can retrieve it with simply noting the UAV’s GPS location. The Accelerometer and Gyroscope will keep the UAV stable at all times. The Barometer senses height of the system, this is done by measuring the atmospheric pressure. The advantages of this would be the option to set the command of ‘altitude hold’, once you reach this altitude, hold this height until you reach this point. This becomes very helpful with applications where you want to avoid detection or hold a stable height for film recording. The Magnetometer on board is essentially a compass, with you knowing which direction you are heading at all times. Gimbol Control is a servo motor control output to change the X and Y orientation upon the position of where a Camera is mounted, perfect for shooting a particular scene of movie from the air. FPV on the microcontroller works as a bridge for the incoming data, the data comes in from the camera and then transmitted wirelessly down to the base station using a RF wireless device.
Figure 6 Typical Camera Gymbol
Figure 7 FPV Goggles
Combat Roles
Combat missions may be carried out in a wide number of areas in the world in contrasting terrain and atmospheric conditions. These may range from the snow and ice of the poles to the heat of the tropics. These conditions could be combined with considerable height in mountainous areas. This is where the use of a UAV becomes desirable.
Surveillance
Surveillance operations happen over a number of ranges, from short to medium and are intended to expose an immediate or short term threats. They are usually required to be covert in order not to alert the enemy in question. Examples of the type of covert mission is to establish the extent of enemy positions or movements or the infiltration of insurgents into friendly territory. In the past this would have been carried out by forward reconnaissance teams on foot, but under modern conditions they would lack the mobility to cover the vast amounts of territory in the short time needed to gather information. The use of UAV systems offer a much more successful solution. Hand launched Fixed Wing UAVs are in regular use within the USA armed forces, the have the gains of being relatively cheap, but have downsides of high loss rates and short range distances of up to 10 kilometres. Catapult launched Fixed Wing UAV’s are better suited to longer ranges under good weather conditions of up to 50 kilometres. Whereas VTOL UAV systems have comparable range under more adverse weather conditions. They also are more covert than Fixed Wing UAV’s.
IED and Landmine Detection
Buried items and surface items hidden by vegetation can be easily detected by use of high definition, thermal imaging cameras. In conditions when the temperature is changing, different materials absorbs or lose heat at different rates therefor gaining more noticeable thermal contrasts. Place one of the cameras onto a a UAV flying the path of where the troops are heading, with information in the form of a video feed being transmitted down, given the troops added insight of the possible locations of IEDs.
Commercial Roles
Aerial Photography
Using high resolution still and video cameras. Pictures may be obtained of geographical or constructed features, such as historic buildings or forest planteries. Considering the cost of a UAV to gain aerial photography, compared to hiring a mobile boom lift and a photographer trained to use it. There is a no brainer. The cost to buy a UAV towards hiring a boom lift is roughly similar, not to mention a great deal safer.
Farming Aid
Surveying big crop fields has never been easier, set waypoints into a UAV and gather the data needed, from monitoring growth of the crop to detecting disease within the crop by noticing a change in colour. The same concept can be applied to monitor the amount of cattle within their fields.
Why chose Unmanned Aircraft?
Unmanned aircraft will only exist if they offer advantages over manually operated aircraft. An aircraft system that is designed from the outset to perform a particular role or roles. You must decide the type of aircraft most suited to perform the roles and in particular whether the roles may be better achieved with a manned or unmanned solution, weighing up the pro’s and con’s. In other words it is impossible to conclude that UAVs always have an advantage or a disadvantage compared with manned aircraft systems. For military role where the reconnaissance of heavily defended areas is necessary , the attrition rate of a manned aircraft is likely to exceed that of a UAV, Due to its smaller size and greater stealth, the UAV is more difficult for an enemy air defence system to detect and more difficult to strike with anti-aircraft fire or missiles. Also in such operations where the aircrews safety may be compromised with the threat of attack. With the loss of damaged assets, but equally the loss of trained personnel. UAV operators are under no personal threat and therefor can concentrate more effectively with the operation at hand.
Summary
During the last fifteen years we have witnessed significant advances in the unmanned aircraft and unmanned systems. Major research and development projects funded initially by the military sector, have contributed towards the continuous development and deployment of aerial, undersea and ground unmanned systems with new designs surfacing at an increasing rate. Common objectives and goals of any such designs are improved autonomy through innovative sensing and control plans, enhanced reliability and endurance through advanced materials. New and novel concepts and technologies are required for a more
widespread use of such critical assets, not only for military but also for commercial applications.
According to the market study conducted by Teal Group, UAV expenditures are expected to increase over the next 10 years from the present expenditure of approximately $3.4 billion to $7.3 billion. Over the next decade, the US will represent 73% of the R&D, test and assessment spending on UAV technologies. Europe occupies the second largest market for high-tech UAV technologies and accounts for roughly 20% of the global total research followed by Asia-Pacific, the Mid-East, Africa and the Americas. Civil market represents another potential market for UAVs and is believed to emerge over the next 10 years starting with organizations like border patrol and coast guard that require surveillance systems.
With the added investment due in the future that will progress upon the technology advanced ways we already use to fly our aircraft, you can bet that transportation via an autonomous vehicle will not be unconceivable. At this moment in time there may not be a suitable purpose to choose using UAVs over manned aircraft, but their existence no doubt has a positive impact for both military, commercial and hobbyist users, along with UAVs becoming more and more useful as time progresses.