The availability of unmanned air vehicles: a post-case study

In the era of Declining Defense Dollars, the cost of sophisticated aircraft and highly trained personnel has heightened interest in Unmanned Air Vehicles (UAVs). The obvious lure is the lower vehicle cost (no crew station and crew support systems) and reduced needs for highly skilled air crews. Reconnaissance (commonly called recce) aircraft and their missions are among the commonly sighted applications for UAVs. Today's UAV recce aircraft (such as the Predator) are the genesis of much more sophisticated UAVs of the future. The evolution of the UAV will not be constrained to recce aircraft, but the recce mission will be significant for UAVs. The recce hole has historically been that of a battlefield data collector for post mission review and planning. In the electronic battlefield of the future, that role will be expanded. Envisioned mission for future recce aircraft include real-time scout, target location and fire coordination, battle damage assessment, and large area surveillance. Associated with many of these new roles is the need to store or assess much higher volumes of data. The higher volume data requirements are the result of higher resolution sensors (the Advanced Helicopter Pilotage infrared sensor has a data rate of near 1.2 Gigabits per second) and multi-sensor applications (the Multi-Sensor Aided Targeting program considered infrared, TV, and radar). The evolution of the UAV recce role, and associated increased data storage needs (from higher data rates and increased coverage requirements), requires the development of new data storage equipment. One solution to the increased storage needs is solid-state memory. As solid-state memories become faster, smaller, and cheaper they will enable the UAV recce mission capability to expand. Because of the speed of the memory, it will be possible to buffer and assess (identify the existence of targets or other points of interest) data before committing to consumption of limited storage assets. Faster memory search times and random memory access will permit comparisons of iterative imagery to identify changes (moving-target-indicator or new/missing objects) in real-time. This has three positive effects: (1) Real-time assessment of enemy troops and weapon strengths (coupled with directional data) for planning or fire coordination. (2) Real-time battle damage assessment to accelerate determination of the allocation of friendly assets. (3) Selective storage of imagery (only that which contains points-of-interest) reduces the amount of data storage leading to increased area coverage and mission times. Orbital Sciences Corporation/Fairchild Defense is completing the development of a High-Speed Solid State Recorder which is a critical element of the Enhanced Recce Management System we are developing. The High-Speed Solid State Recorder will be a major part of defining the mission for future UAV recce aircraft.

This paper describes the latest efforts to develop an Automated UAV Mission System (AUMS) for small vertical takeoff and landing (VTOL) unmanned air vehicles (UAVs). In certain applications such as force protection, perimeter security, and urban surveillance a VTOL UAV can provide far greater utility than fixed-wing UAVs or ground-based sensors. The VTOL UAV can operate much closer to an object of interest and can provide a hover-and-stare capability to keep its sensors trained on an object, while the fixed wing UAV would be forced into a higher altitude loitering pattern where its sensors would be subject to intermittent blockage by obstacles and terrain. The most significant disadvantage of a VTOL UAV when compared to a fixed-wing UAV is its reduced flight endurance. AUMS addresses this disadvantage by providing forward staging, refueling, and recovery capabilities for the VTOL UAV through a host unmanned ground vehicle (UGV), which serves as a launch/recovery platform and service station. The UGV has sufficient payload capacity to carry UAV fuel for multiple launch, recovery, and refuel iterations. The UGV also provides a highly mobile means of forward deploying a small UAV into hazardous areas unsafe for personnel, such as chemically or biologically contaminated areas. Teaming small UAVs with large UGVs can decrease risk to personnel and expand mission capabilities and effectiveness. There are numerous technical challenges being addressed by these development efforts. Among the challenges is the development and integration of a precision landing system compact and light enough to allow it to be mounted on a small VTOL UAV while providing repeatable landing accuracy to safely land on the AUMS. Another challenge is the design of a UGV-transportable, expandable, self-centering landing pad that contains hardware and safety devices for automatically refueling the UAV. A third challenge is making the design flexible enough to accommodate different types of VTOL UAVs, such as the AAI iSTAR ducted-fan vehicle and small helicopter UAVs. Finally, a common command-and-control architecture which supports the UAV, UGV, and AUMS must be developed and interfaced with these systems to allow fully autonomous collaborative behaviors. Funded by the Joint Robotics Program, AUMS is part of a joint effort with the Air Force Research Laboratory and the Army Missile Research Development and Engineering Command. The objective is to develop and demonstrate UGV-UAV teaming concepts and work with the warfighter to ensure that future upgrades are focused on operational requirements. This paper describes the latest achievements in AUMS development and some of the military program and first responder situations that could benefit from this system.

Nowadays, Unmanned Air Vehicles (UAVs) have become more and more important. These vehicles are employed in many applications from military operations to civilian tasks. Under situations where global positioning system (GPS) and inertial navigation system (INS) do not function, or as an additional sensor, vision systems can be used. In recent years omnidirectional camera usage has experienced a remarkable increase. In many fields innovative research has been done by this camera which captures 360° view in a single frame. However, employment of omnidirectional cameras in UAVs is very new. In this paper, we present the use of catadioptric systems in UAVs. The parallel lines that exist on many structures in an urban environment are used by the algorithm for the estimation of the attitude of the UAV. After explanation of the algorithm, the UAV modelling and control will be presented. Various simulations have been done to present the effectiveness of the estimation algorithms as well as the UAV controllers. Finally, we will present the experiments and the results of the estimation and control algorithms on a real model helicopter.

The problem of cooperative obstacle avoidance by a group of unmanned ground vehicles (UGVs) and unmanned air vehicles (UAVs) during a typical search mission is addressed in this paper. The group of UAVs and UGVs are performing a search operation in the designated area. All the UAVs and UGVs are equipped with a vision sensor/LIDAR to identify the possible obstacles in the search space. Due to their operation on the ground, UGVs are more likely to encounter obstacles. The obstacle avoidance for UGV under the event of sensor failure is done with environment information from the nearest UAV. The UAV plans its trajectory according to the UGV’s expected future trajectory, leading towards the base station. The UGV replans its trajectory to avoid obstacles after obtaining the information from its nearest UAV. A simulation study is performed with 10 UAVs and five UGVs performing a search mission in 1[Formula: see text]km[Formula: see text][Formula: see text][Formula: see text]1[Formula: see text]km area. The proposed obstacle avoidance method is experimentally validated in the outdoor environment with an autonomous UAV equipped with a camera and an autonomous UGV navigating based on GPS localization and environment information from the UAV.

Flapping wing unmanned air vehicles (UAVs) are small light weight vehicles that typically have short flight times due to the small size of the batteries that are used to power them. During longer missions, the batteries must be recharged. The lack of nearby electrical outlets severely limits the locations and types of missions that these UAVs can be flown in. To improve flight time and eliminate the need for electrical outlets, solar cells can be used to harvest energy and charge/power the UAV. Robo Raven III, a flapping wing UAV, was developed at the University of Maryland and consists of wings with integrated solar cells. This paper aims to investigate how the addition of solar cells affects the UAV. The changes in performance are quantified and compared using a load cell test as well as Digital Image Correlation (DIC). The UAV platform reported in this paper was the first flapping wing robotic bird that flew using energy harvested from on-board solar cells. Experimentally, the power from the solar cells was used to augment battery power and increase operational time.

GPS enhances the ability of UAV system to control the air vehicle, an electronic map displays dynamically the position results and happenings around the UAV. To combine GPS and electronic map, visual UAV dynamic location and navigation is realized.

In this chapter, preliminary sizing and performance calculations of unmanned air vehicles (UAV), with relation to its propulsion system, are explained. Starting with the mission profile of the air vehicle, which is one of the important design drivers, the UAV is sized for the requirements. The requirements in design consist of a set of target values (e.g., payload amount to be carried, range, endurance time, cost, etc.). Additionally, the parameters within mission profile such as cruising altitude and speed of aircraft affect engine type, power level required, fuel quantity, and therefore general dimensions and the gross weight of the aircraft. It is often an iterative process to size the air vehicle and engine together. UAV is designed in a loop of calculations in which sizing, flight performance, and engine performance are done for each phase of the mission or flight profile to satisfy the overall design mission and requirements.

Great efforts are devoted for integrating Renewable Energy Sources (RES) on the propulsion system of Unmanned Air Vehicles (UAVs). This is applicable to small UAVs, having a horizon to expand to large UAVs within the next decades. For the conventional propulsion systems to be replaced, the required power needs of the aircraft should first be examined. The required power depends on the UAV's flight stage from takeoff to landing, whereas its calculation varies with regard to the propulsion system type, which is separated into two main categories, the propelled‐driven engines and the jet engines. Two obstacles are arising. First, the parameters needed for the power estimation are commercially sensitive and second the analysis alters with respect to the engine's type. This paper focuses on the mathematical analysis of the required power for both the main propulsion systems, presented extensively for each flight phase, proposing, at the same time, a parameter estimation method which is applicable to any UAV type. The main purpose of this paper is to act as a guide for the calculation of any type UAV's required power at any flight stage. To validate the analysis, the MQ‐9 Reaper/Predator B, a High Altitude Long Endurance (HALE) turboprop UAV produced by General Atomics is analysed. Its unknown parameters are estimated and based on a selected flight profile, the required power in terms of horsepower from takeoff to landing is assessed, for two scenarios regarding the aircraft's initial weight. In the first scenario the UAV has the maximum gross takeoff weight, whereas in the second scenario it does not carry any payload. The estimated required shaft power per flight phase for each scenario is then marked into the TPE331‐10 turboprop engine characteristic curves.

The work presented concerns the application of value driven engineering design to the Sophomore Design Project of an Unmanned Air Vehicle (UAV) conceptual/preliminary design. In this Sophomore Design Project, offered to the Aviation Program students, student teams performed the conceptual/preliminary stages of design of a small UAV (below 5 kilograms) based on a given set of requirements and constructed the selected UAV design in balsa wood. The student taking this course were divided in groups of 4-5 persons and worked to propose, plan and manufactured an aircraft design while they were supervised by a faculty/lab instructor/lab engineer. The student teams were evaluated on their ability to coordinate efforts to propose the aircraft design criteria, aircraft components, resources, implementation schedule, estimate cost and finally construct the optimal UAV design. A large number of UAV configurations and geometries were considered and evaluated in the Multi-Disciplinary Design Optimization (MDO) in order to search the widest possible design space. Moreover, the designed system’s operational capabilities and acquisition cost, based on the UAV user’s needs and priorities, were employed in the value model to compare the different design alternatives and select the optimal. Following the selection of the flying wing as optimal design, manufacturing of the prototype in balsa wood was performed by the students, with the two student groups constructing this UAV.

Structural health and usage monitoring of unmanned air vehicles is of increasing interest not only for the evaluation of flight loads and the use of data in order to estimate the remaining lifetime of the structure but also for a fast and reliable assessment of structural impacts due to unexpected events that can produce significant loads on the structure, such as hard landings and gusts. This is especially important with composite material structures where damage is quite often barely visible. In-flight load and usage monitoring enables fast turnaround times and increases the availability of the unmanned air vehicle. The Spanish National Institute for Aerospace Technology has been developing, for over two decades now, unmanned air vehicles for surveillance, reconnaissance, and aerial targets. At the moment, a health and usage monitoring system for the Spanish National Institute for Aerospace Technology’s medium altitude and long endurance unmanned air vehicle called MILANO, based on fiber Bragg grating sensors that measure strain and temperature, is being developed. The sensors are integrated in the outer and central wing box and the central and rear fuselage. The health and usage monitoring system is based on the experience gained during flight test activities of the tactical unmanned air vehicle SIVA, an all-composite material unmanned air vehicle developed and assembled by Spanish National Institute for Aerospace Technology. One SIVA is instrumented with 15 fiber Bragg grating sensors that measure both strain and temperature in different structural points of interest, such as the outer wing, the wing attachment, the front and rear fuselage, a stabilizer, and the landing gear. The use of optical sensors instead of electrical sensors has the advantages of lower weight penalty, longer durability, and total immunity to electromagnetic interferences. Structural deformations of the unmanned air vehicle have been measured during flight and used to calculate structural flight loads. Temperature-induced thermal strains have been compensated for. This article explains the results and data evaluation of the performed flight tests, describes the equipment used and the sensor applications, and presents the health and usage monitoring of Spanish National Institute for Aerospace Technology’s tactical and medium altitude and long endurance unmanned air vehicles.

With the rapid development of 5G networks and the availability of small Unmanned Air Vehicles (UAVs), low cost and multi-view live drone broadcasting becomes possible. However, limited by the load capacity, small UAVs cannot uninterruptedly complete long-time and long-distance shooting tasks. This paper focuses on the energy circularly recharging strategy to solve the conflict between small UAV load capacity and mission execution capability in the live marathon broadcast scenario. Based on fixed flight paths of the UAV-T (Task UAV), we adopt a greedy strategy to deploy temporary energy supply stations along the marathon course tracks. UAV-Rs (Replenishment UAVs) depart from the energy supply stations and resupply the UAV-T with energy by air docking; then, the UAV-T needs not fly back to resupply the energy on the ground; and the live drone broadcast task is also uninterrupted. Simulations show that the cost of deploying temporary energy recharge stations can be greatly reduced by using the aerial recharge scheme.

This work describes the optimization process of a morphing wing for an unmanned air vehicle (UAV) by using multi-objective gradient based optimization algorithm in which maximization of lift to drag ratio and minimization of bending moment at wing root chord plane are defined as the objective functions. Six different optimization problems are solved by changing weighted sum coefficients of the objective functions in order to observe the morphing wing planform and the airfoil shape change. According to the results, 15.2% lift to drag ratio increase is obtained while the increase in the bending moment is 2%.

This paper proposed an unmanned air vehicle (UAV) swarm task and resource dynamic assignment algorithm based on task sequence mechanism. By establishing a task sequence, each UAV strictly separates the necessary task time and synchronization waiting time. For the found new targets, each UAV quickly determines its available time period. According to the available time and task resources, an auction algorithm and consensus algorithm are used to decompose the task assignment into initial distributed assignment phase and swarm consensus phase to develop real-time conflict-free task solutions for UAV swarm. The simulation experiment verified that the algorithm could assign different tasks to UAVs in a real-time distributed manner with the limited resources of each UAV.

In recent years, a renewed interest in the development of unmanned air vehicles (UAVs) led to a wide range of interesting applications in the fields of reconnaissance and surveillance. In these types of mission, the noise produced by propeller driven UAVs is a major drawback, which can be partially solved by installing an electric motor to drive the propeller. The evolution of high performance brushless motors makes electric propulsion particularly appealing, at least for small and medium size UAVs. All electric propulsion systems developed to date are though penalized by the limited range/endurance that can be provided by a reasonably sized battery pack. In this paper we propose a hybrid propulsion system based on a recently developed, high efficiency microturbine which can be used to power an electric generator, thus providing a significant range/mission time extension. The UMTG is undergoing operational testing in our Laboratory, to identify its most suitable configuration and to improve its performance: a new compact regenerative combustion chamber was developed and several tests were performed to reduce its weight and size so as to increase the vehicle payload. In a high range/endurance mission the ultramicro turbine drives the electrical motor that powers the propeller only during the cruise phase (the so-called “transfer to target”), while in the final approach, in which a quiet flight attitude is mandatory, a (smaller) battery pack drives the motor directly and the UMTG is turned off. The mission requirements considered for the preliminary design of the UAV consist of a long endurance (> 12 hours) step, with a cruise speed of 33.3 m/s and a dash speed of 45 m/s at an altitude of 5000 meters. The maximum take-off weight is 500 N, with a payload of 80 N. Under the above assumptions, a flying wing configuration for the UAV was defined, with a length of 1.6 meters and a span of 2.5 meters. A system of elevons assures the pitch and roll motion while a double vertical tail, in which a pusher propeller is lodged, guarantees the yaw stability and control.

The high rate at which birds damage farm crops and the attendant high cost of using effective bird control mechanism has discouraged many farmers from cultivating certain crops (most especially rice). The most used method of bird control is scaring method. This is usually done by using scaring devices. The main problem with the bird control methods currently adopted is that they require human intervention for it to be effective. This project proposes the total elimination of human involvement in bird control by substituting it with swarm of unmanned air vehicle (UAV). Swarm of unmanned air vehicles (UAVs) were simulated to survey farmland in order to scare away birds. To ensure that all the areas of the farmland are inspected, the farmland is divided into equal compartments for the UAVs. The simulation was designed in virtual robot experiment platform (V-REP). Algorithms were implemented for both UAV inspection and allocation; the result of the simulation show that swarm of UAVs can be used to replace human interventions in bird control.