First Flight of Scaled Electric Solar Powered UAV for Mediterranean Sea Border Surveillance Forest and Fire Monitoring

Transcription

1 Aerotecnica Missili & Spazio, The Journal of Aerospace Science, Technology and Systems First Flight of Scaled Electric Solar Powered UAV for Mediterranean Sea Border Surveillance Forest and Fire Monitoring G. Romeo a, M. Pacino a, F. Borello a a Politecnico di Torino Dipartimento di Ingegneria Aerospaziale Abstract Research is being carried out (as part of several EC funded projects) with the aim of designing Very-Long Endurance Solar Powered Autonomous Stratospheric UAV (VESPAS-UAV) and manufacturing a solar powered prototype. This It could play the role of a pseudo satellite, with the advantage of allowing a more detailed land vision due to the relative closeness to the land and at a much lower cost than a real satellite. 300km diameter area could be monitored by each of these platforms. The full scale HELIPLAT R UAV and SHAMPO UAV were designed using the most advanced tools to obtain an endurance of 4-6 months and to be operable in almost all typical environmental conditions (jet stream up to 180km/h) at stratospheric altitude (17-20 km). During the day it will fly with 8 brushless electric motors in which power is generated by thin high-efficiency solar cells that cover the aircraft s wing and horizontal tail. At night it will be powered by a fuel cell system fed by gaseous hydrogen and oxygen stored in pressurized tanks. A payload of up to 150kg, with available power of up to 1500W, could be installed on board for several kinds of global monitoring of environmental and security applications (GMES). A scaled size prototype (wing span 24 m, length 7 m) has been built in order to show the technological feasibility of the project. The Small Electric Solar Unmanned Airplane (SESA) flying model was built to carry out several experimental flight tests with a small solar powered UAV and to demonstrate some critical technologies and applications. The brushless electric motor was powered by high efficiency (21%) mono-crystalline silicon arrays and LiPo batteries. The structure was made entirely of fibreglass reinforced plastic, except for the wing box, for which carbon-fibre composite materials were also used. A wing with span of 7m was manufactured and 2 m2 of solar cells were bonded over the wing skin, in this way obtaining a far higher endurance of up to 8-10 hours in June and July in a level flight. With a total gross weight of 35 kg, the payload capabilities are of the order of 5 kg. The experimental tests validated several critical technologies for high altitude very long endurance flight: high efficiency solar cells, an electric brushless motor, controllers, video and thermo camera image transmission, telemetry system, autopilot. 1. Introduction UAV technology has advanced sufficiently for the aeronautical industry to be ready to expand into a new added value Commercial industry - the young and growing Civilian Unmanned Air Vehicle (CUAV) industry. The total UAV market is growing at a rapid pace and it is imperative that the European community should make a serious effort to attain a significant segment of this market. The wide range of applications for civilian UAVs, will open up a variety of markets for potential sales and economic growth. Competitiveness in Aerospace is strategically important and the primary competition for the European community comes from the United States. As the civilian market c Copyright 2009 by G. Romeo. Published by AIDAA with permission. All information regarding HeliPlat R, Shampo & SESA Solar Powered UAV is the Propriety of Prof. G. Romeo, the Politecnico di Torino and cannot be reproduced without his authorization. All rights reserved. for UAVs increases, a great potential will be created to maintain and strengthen the competitiveness of the European aerospace industry in a new technology area, which will guarantee and create highly qualified jobs for the future. In a recent business market study carried out by Frost and Sullivan, the global market for UAVs in civil and commercial applications was estimated to be close to $2bn by 2014 [?]. The largest market shares are expected to pertain to Coastguard and Maritime Surveillance operations, Border Security and Forest Fire Management. The Scientific Community could benefit in many ways from employing UAVs in the civilian sphere. The utilisation of UAVs for border and costal patrol, homeland security, maritime surveillance, Eye-in-the-sky surveillance, will allow better law-enforcement for the protection of citizens and the integrity of the borders. The utilisation of UAVs for forest fire mapping, real-time monitoring of seismic-risk areas, air turbulence, vol-canoe eruptions and other natural phenomena will ensure that the public is aware of imminent disasters and can therefore 8

2 First Flight of Scaled Electric Solar Powered UAV for Mediterranean Sea Border Surveillance Forest and Fire Monitoring 9 prepare for their occurrence. Under the coordination of the first author, a research is being carried out (as part of several EC funded projects) ( [?], [?], [?], [?] ) with the aim of designing Very-Long Endurance Solar Powered Autonomous Stratospheric UAV (VESPAS- UAV) and manufacturing a solar powered prototype. This could play the role of pseudo-satellite, with the advantage of allowing more detailed land vision, due to the relative closeness to the land, with continuous earth observation and at a much lower cost than real satellites. Satellite sensors can offer good accuracy - spatial area trade-off, especially when modern high resolution satellites are taken into account - but such high accuracy data are quite expensive today. Several satellite systems used for earth observation are useless for continuous real-time border surveillance because of their limited spatial resolution. All the Mediterranean Sea border, from Turkey to Spain and the Canary Islands could be electronically controlled by 9-10 platforms from a high altitude (17-20 km), with very-long endurance (several months) stratospheric UAV (payload up to 150 kg, power available for payload up to 1500 W). It is essential to control who and what enters European countries in order to prevent the admission of terrorists and instruments of terror across borders, along coastlines and harbours. Continuous (24h by 24h) border monitoring would be guaranteed and in such a way would drastically reduce service costs and tedious work (Fig. 1). A 300km diameter area would be monitored by each of these plat-forms. No special projects are at moment known to be underway on border surveillance of the Mediterranean Sea. This service is at present made by several military ships or piloted airplanes with several people on board and it is therefore a costly business. Furthermore, only spot controls are made, because of the large extension of the border. In Spain, the coast from Morocco is controlled (limited to km) by a radar system (SIVE) at a cost of 145 MEuro. Similar, very expensive systems are being installed all along the Italian coast (more than 2000 km). At which cost? The Italian Coast Guards have high costs for their ATR 42MP equipped for border surveillance. With minimum crew of 7 the cost of the aircraft is around Euro for a hour of flight. The VESPAS platform could also be conveniently used, with proper fire sensing tools, for forest fire monitoring (Fig. 1). This service is frequently requested in all Southern Europe (Spain, Italy, the South of France, Greece, etc.) for airborne imaging of uncultivated land fires and other natural and human-induced disasters. Several payloads are available and most of them are used from satellites; the existing and planned operational space-borne sensors, because of the very high altitude at which they operate ( km), show serious limitations if accurate parameters have to be obtained. As a result, they only allow detection of very large fires, and not in a continuous matter. Higher performances are available from electro-optic or infrared sensor airborne installation and flight altitudes of km and it is possible to detect shorter flame lengths than one meter. Just 4-5 VESPAS stratospheric platform could cover Italy from North to South. Figure 1. Sea and terrestrial border monitoring and fire monitoring. Electronic surveillance all over the South of Europe could clearly be obtained with a good HeliPlat Network. Early forest fire mapping could be realised with infrared remote fire sensing tools. The maximum in the spectral radiance distribution of vegetation fires occurs in the mid wave infrared (MWIR) region at 3-5 µm. Therefore, the mid wave infrared spectral range is commonly recognized as the optimal spectral range for fire detection. In order to reduce the high flight costs of piloted aircraft, it is necessary to have unmanned vehicles with very long endurance (several weeks or months) to obtain an efficient service. UAVs are less expensive than other manned aircraft used for border surveillance. With an UAV flying at an

3 10 G. Romeo, M. Pacino, F. Borello altitude of km and with proper sensors, it is possible to detect illegal boats or people along borders and with Total Life Cycle Costs of around Euro/hour of flight [?]. The main advantage of VESPAS is that this system has less climbing and descending events, which is important when considering interference with aviation traffic. Other HALE-UAV configurations offer a very limited endurance (24-36 hours), which would drastically increase any potential collision risk with civil aviation traffic. Double the number of UAVs would be necessary to continuously guarantee the surveillance service, thus the Total Life Cycle Cost System would be increased to a great extent. Other Medium Altitude Long Endurance (MALE) - UAVs offer a further disadvantage; a much higher number of UAVs are necessary to continuously cover the entire Mediterranean Sea, since the covered area decreases with the square value of the flying altitude (Fig 2); the Total Life Cycle Cost system would increase remarkably with a MALE configuration. Very high endurance, in fact, calls for high mission reliability requirements of the air vehicle, its systems and its payload. Figure 2. HALE monitoring application advantages An integrated, multi-sensor, interoperable system, based on the use of remote and local means of surveillance (e.g. UAV, satellite, etc..) and multiple sensor concepts (e.g. I/R and E/O sensors, SAR, hyper spectral, sensor fusion, processing, etc.) for border surveillance from a stratospheric altitude is being studied to detect, even in adverse climatic weather, boats with illegal migrants or terrorists reaching the south European coasts from North Africa or Middle Eastern countries or illegal fishing boats. The information obtained will be transmitted to the control station and from here to a network where Maritime Traffic Centre data are exchanged through Internet. It also provides a powerful tool to characterise the marine environment for habitat monitoring. All those features lead to: Reduced costs per Flight Hour through an extensive increase in endurance flight hours. Potentially increased acquisition costs, but reduced maintenance and spare part cost. Reduced costs - larger area coverage per aircraft, requiring fewer aircraft per area. Improved operational safety - due to the flights being above aviation traffic and above adverse weather conditions, resulting in limited interference with aviation traffic. Not even one real very-long endurance stratospheric platform is actually available in Europe. A few are already available in the USA. Several types of high altitude solar powered platforms (HASP) were designed in the past. At the end of 1994, NASA started the ERAST (Environmental Research Aircraft and Sensor Technology) program [?] ; one of the four drones is the solar platform Pathfinder that exceeded 24 km of altitude in a 15 hour flight. In the summer of 2001, the Helios solar-powered platform sets a new world record of metres, aiming at a flight of several days in year A solar-powered, unmanned aircraft is being developed by Boeing and QinetiQ for the US Government (US Defence Advanced Research Projects Agency) for use in military and civil tasks [?]. Unmanned long endurance (years) air vehicles could be used to replace conventional satellites. POLITO (under the scientific guidance of Prof. G. Romeo) has been working on one of the three existing world projects on solar powered aerodynamic stratospheric platforms for several years. After preliminary funding by the Italian Space Agency, a very great push to the project was obtained by the financial support received from the European Commission in the field of stratospheric platforms (HeliNet, Capecon, En-fica- FC, Tango) ( [?], [?], [?], [?]). The possibility of medium-long endurance (4-6 months) for a stratospheric platform can be obtained through the application of an integrated Hydrogen-based energy system. This is a closed-loop system: during daytime, the power generated by thin high efficiency solar cells that cover the aircraft s wing and horizontal tail supply power to the electric motors for flying and to an electrolyser which splits water into its two components, hydrogen and oxygen. The gases are stored in pressurized tanks and then, during night-time, used as inlet gases for the fuel cell stack in order to produce electric DC power and water which is supplied to the electrolyser. Since fuel cells represent clean and efficient

4 First Flight of Scaled Electric Solar Powered UAV for Mediterranean Sea Border Surveillance Forest and Fire Monitoring 11 power generation, they are a suitable alternative to con-ventional energy sources. POLITO will capitalize on the results and findings that are being obtained in the on-going EU funded project ENFICA-FC (ENvironmentally Friendly Inter City Aircraft powered by Fuel Cells) co-ordinated by Prof. G. Romeo. A twoseater electric-motor-driven airplane powered by fuel cells is being developed by converting a high efficiency existing aircraft and it will be validate by a flight-test which is planned for October 2009, ( [?], [?]). The Heliplat/Shampo UAVs are being analysed as part of the EC funded project TANGO [?] (under the scientific guidance of Prof. G. Romeo for Polito) in cooperation with several satellite systems for a few civil applications of GMES (Global Monitoring Environmental and Security). Demonstrations will integrate satellite telecommunication solutions with on-going GMES developments in the framework of fishery management. Inclusion of UAVs in the global relay infrastructure enables quasi real time and continuous access to dedicated zones for monitoring or surveillance. A flight test is being prepared with a scaled solar powered UAV for a final integration with on-going GMES developments in the framework of fishery man-agement. 2. HELIPLAT R VESPAS The full scale HELIPLAT R (HELIos PLATform) UAV (Fig. 3) was designed using the most advanced tools to obtain an endurance of several months (4-6) and to operate in almost all typical environment conditions (jet stream up to 180km/h) at stratospheric altitude (17-20 km). ( [?]- [?]). The vehicle should climb to km by mainly taking advantage of direct sun radiation and thereafter maintaining a level flight; the electrical energy that is not required for propulsion and payload operation is pumped back into the fuel cell energy storage system and, during the night, the platform would maintain altitude through use of the stored (solar) energy; the geostationary position would be maintained by a level turning flight. A computer programme was developed to design a platform that is capable of remaining aloft for a very long period of time and to gain a thorough understanding of the feasibility of a near term aerodynamic high altitude concept, electric motor, solar and fuel cell technology, with special attention to stratospheric platforms. The solar radiation changes over one year, the altitude, wind profiles with altitude, masses and efficiencies of the solar cells and fuel cells, aerodynamic performances, structural mass, etc were taken into account. Extensive use of high modulus Carbon-fibre was made in designing the structure to minimize the airframe weight. The platform project was completed up to a quasi-final design stage. A numerical aerodynamic analysis was performed to obtain the highest efficiencies of the whole wing and airplane. Several experimental tests were carried out in a Low-Speed-Low- Turbulence Wind-tunnel and a very good correlation was obtained between the analytical and experimental results. A first HELIPLAT R configuration (Fig. 3) was worked out, as a result of the preliminary design study. The platform is a monoplane with 8 brushless motors, a twin-boom tail type, horizontal stabilizer and two rudders. The design procedure followed in the analysis was based on the energy balance equilibrium between the available solar power and the required power for flying; the endurance parameter was in particular fulfilled to minimise the power required for a horizontal flight. The main characteristics for a flight at 38?N latitude and a design altitude of 17 km are: Total weight: 8500N; Wing Area:176m2; Span:73m; Required Power:7500W; Aspect ratio=33; Cruise Speed = 71 km/h. A payload of up to 130kg, with available power of up to 1300W, will be installed on board for several kinds of global monitoring of environmental and security applications (GMES). A numerical aerodynamic analysis was performed to obtain the highest efficiencies of the wing and airplane including the propellers (Fig. 3), by using the VSAERO software, at the Reynolds numbers flight. Advanced design tools (such as CATIA) (Fig. 3) and FEM structural analysis (MSC/ PATRAN/ NASTRAN) were used to design the advanced composite wing (about 75m long), payload housing, booms and tail structures, and to obtain the highest structural efficiencies. Extensive use of high modulus graphite/epoxy material was made to obtain a very light-high stiffened structure. A 1:3 scaled size prototype (wing span 24m, horizontal tail span 10m, length 7m) was built in advanced composite material (high modulus CFRP) in order to show the technological feasibility (Fig. 4). EADS - CASA Space manufactured the single CFRP elements: tubular wing spars and ribs, horizontal and vertical tubular tail spars and ribs, booms and the metal fittings. The POLITECNICO-DIASP, and ARCHEMIDE Advanced Composite, assembled the different parts of the aircraft (wing, horizontal and vertical tails, booms) and the whole aircraft. Several shear/bending/torsion static tests (Fig. 4) were performed in our laboratory on the complete manufactured scaled-size prototype and a very good correlation was found between the in-house developed numerical analysis and the FEM analysis. Mechanical equipment was designed and manufactured to perform the test; a steel supporting structure to sustain the scaled prototype and the tree-beam systems and the hydraulic jack to apply the load. Two trolleys were used to support the tree-beam system in such a way that the system adapts to the prototype s deflection behaviour. A dummy fuselage was designed to apply

5 12 G. Romeo, M. Pacino, F. Borello Figure 4. 1:3 Scaled-size HeliPlat R UAV. Figure 3. HeliPlat R Configuration, Aerodynamic Results and 3D details. the expected loads to the centre of the model. Strain gauges and transducers were mounted along the main spar of the wing in order to estimate deformations and wing deflection. The strain results along the wing, for flight conditions corresponding to a cruising flight of the n-v diagram (maximum limit load n = 3), as well as the wing deflection are reported in figure 5; a maximum wing tip deflection of 500mm (left) and a maximum wing strain of 650 microns were recorded. A very good correlation was obtained between the analytical (in-house developed theory) [?], numerical (Nastran) and the experimental results. The maximum limit load (n = 3) was reached without any residual detrimental effect. The prototype was than subjected to the ultimate load (n=4.5) to obtain the structural safety margin; again in this case, no detrimental effects were recorded. A static test up to failure load was carried out up to more than twice the limit load (N = 7.5) obtaining a very good correlation between the analytical and experimental failure results. A lighter structure shall be designed for the final project, based on this experimental results. The results obtained in the CAPECON project [?], confirm the feasibility of a solar powered stratospheric UAV (SHAMPO satisfying the requirements of a long endurance stationary flight). A detailed aerodynamic and structural design, the flight mechanics and the electric systems was completed by the Politecnico di Torino up to a quasi-final design. A greater aerodynamic and structural efficiency was obtained allowing s higher payload mass (150 kg) and power (1.5 kw). (Fig. 6) 3. Small Electric Solar Unmanned Airplane The flying model of the Electric-Plane was built, as part of the EC funded project CAPECON, to carry out several experimental flight tests with a small UAV in order to demonstrate some critical technologies and applications. The starting model (1:2.8 scale replica

6 First Flight of Scaled Electric Solar Powered UAV for Mediterranean Sea Border Surveillance Forest and Fire Monitoring 13 Figure 6. CAPECON SHAMPO Configuration, Aerodynamic Analysis and 3D details. Figure 5. 1:3 Scaled-size HeliPlat R UAV and Shear/Bending and Torsion Tests and Results. of the Super Dimona (wing span 5.8m, weight 20kg, efficiency 24, minimum cruise speed of 15m/s) was modified by replacing its combustion propulsion system with an electric which included a single brushless motor and a NiMh battery system. The structure was realized using fibreglass reinforced plastic and carbonfibre composite materials for the wing spar. The payload capabilities are of the order of 5-6 kg. As part of the EC funded project TANGO, the NiMh batteries were substituted by rechargeable LiPo batteries, which are mainly utilized during the take-off phase. A new 7m wing span was manufactured and 2 square meters of thin high efficiency (21%) mono-crystalline silicon arrays were bonded over the wing skin (Fig. 7); during the level flight the necessary power is obtained from the solar cell system covering the wing, and in this way a far higher endurance of up to 10 hours can be obtained during June and July. All the structures were designed according to EASA-VLA to withstand a limit load of 3.8. The power produced by the SESA solar cell during the day hours and for different months is reported in Fig. 8. The main characteristics of the Small Electric Solar Unmanned Airplane (SESA), are: Wing span: 7m; Wing area: 2.2 m2; Total gross weight: 35kg; Max Solar Power: 370-

7 14 G. Romeo, M. Pacino, F. Borello 395 W (45-36 N, June); Max power brushless Motor: 3000W; Horizontal Flight Power: 350 W; Minimum Speed: 36 km/h. this model is no longer active. In September 2007, the Zephir, UAV solar model by Qinetiq, was flown in New Mexico. The experimental tests carried out up to now have validated a few critical technologies for high altitude very long endurance flight: high efficiency solar cells, electric brushless motor, controllers, video and thermo camera images transmission, telemetry system, etc. These results shall be very useful to our group for the future projects Power electronic system The flight management electronic power system is reported in Fig. 9. Figure 7. Small Electric Solar Unmanned Airplane SESA. Figure 8. Daily SESA Power for several months. SESA made its first flight powered by solar energy in October 2007, near Turin (45 latitude North) at an altitude of about 300m [?]. The plane is the first European Solar powered light UAV to fly in Europe. In the 90 s, DLR (German Aerospace Centre) manufactured and flew the Solitair UAV scaled solar model but Figure 9. SESA Power electronic system. The power produced by the solar cells is directly supplied to the brushless electric motor for level flight. During take-off and climbing, or for some particular manoeuvres requiring more power, the power is also supplied by the LiPo batteries. The solar panel is composed of a parallel circuit series of 130 solar cells each with efficiency of 21.5% (@1000 W/m2 and 25 C). The maximum solar panel voltage is 43.5V. The development of the MPPT electronic device (Maximum Point Power Tracking) was of particular importance for the success of the flight mission in order to optimize the maximum power that could be obtained by the solar cells and to improve endurance (Fig. 10). The inverter will supply power (also more than 3kW) to the brushless electric motor. The cooling of the inverter, to avoid shut-off of the system as a maximum allowable temperature is reached, is also an important feature. Any solar cell power exceeding the required flight power will be used to recharge the battery Payload system In order to show the opportunism of introducing such platforms in surveillance or monitoring systems, the model has been equipped with a wireless colour

8 First Flight of Scaled Electric Solar Powered UAV for Mediterranean Sea Border Surveillance Forest and Fire Monitoring 15 CCD camera (40x, resolution 720x576 pixel) and with an infra-red thermo-camera (160x120 pixel); the video camera zoom can be remotely controlled by an RS Both cameras can transmit directly (at 1.2GHz), in a range of about km in open air and through an appropriate capturing peripheral device, to a PC (Fig. 11). 1. True Air Speed 2. Voltage and Current of the brushless motor 3. Voltage, Current and consumption of the main motor battery 4. Temperature Service of the motor and inverter. Figure 10. SESA solar cell curve and MPPT. The PC could be used to analyze images in realtime, for example, to automatically detect small forest fires Remote control and telemetry system At present the UAV is remotely controlled by a radio modem. Up to 12 servo-actuators can be controlled for the UAV flight. The elements actually controlled are: rudder and tail gear, 2 elevators, 2 ailerons, motor rpm. A telemetry system (Fig. 12) has also been installed on board to transmit in real time all the most critical data for the safety of the flight to the ground control station. The following data are recorded and sent on wireless to the Ground Control Station in order to continuously have the real flight conditions of the aircraft: 3.4. Autopilot system and mission architecture An autopilot has been acquired and is being installed on board for an autonomous flight of up to 50km through the use of a highly integrated data acquisition, processing and control system; this includes all the necessary components for aircraft control. The Autopilot system (designed and built by Mavionics GmbH,D) consists of three main parts: 1) The TrIMU Sensor Block contains a complete 3-axis Inertia Measurement Unit (IMU) and two pressure sensors for barometric altitude and airspeed determination. It gener-ates up to 12 independent servo control signals. 2) The Navigation Core hosts a sophisticated navigation filter for GPS/IMU data fusion which enables precise and long-term stable determination of the position, velocity and the Eulerian angles and to obtain a reliable attitude determination. 3) a Satellite Navigation Receiver. 16 channel GPS receiver with high sensitivity and integrated ceramic patch antenna. The connection between the Core and Satellite Navigation Receiver is only through power and digital lines thus significantly reducing interference. The on-board autopilot system communicates with Ground Control via a dedicated, direct bidirectional data link, using a radio modem which operates in the European 868 MHz band. The A/P periodically sends data (GPS time, position, Eulerian angles, flight speed, etc.) to the GC at a rate of 4 Hz, and health monitoring data (battery voltage, electric motor current but with a lower data rate. Direct control through the radio modem does not lead to any latency problems; however, when we switch to the Iridium L-Band Transceiver, the amount of data per Status Message (80bytes per data packet) from the aircraft does not seem to be a problem but the update frequency and latency could be critical. No real problem is foreseen when using the L-Band Transceiver (weight 650g, latency less than 1 sec). However, a latency of 5 to 20 seconds could be possible for a Short Burst Data communication (weight 170g). Since the autopilot operat-es even without connection to the GC, latency is not a direct safety issue for the automatic flight itself; once sent to the autopilot, the A/P will follow the splines even without assistance from the GC. Therefore, latency is not a serious issue for the safety of the automatic flight itself, but latency is important for any kind of manual intervention and hence also becomes a safety issue. Furthermore, frequent losses of connection means a loss

9 16 G. Romeo, M. Pacino, F. Borello of telemetry data and information concerning battery consumption and loss of the Endurance control. Moreover, a delay in transmitting the picture of a ship, for example, taken by the onboard camera could cause some problems in detecting the illegal boat. The small size of the demo scaled UAV precludes the use of high bandwidth geo satellite systems. The only systems capable of being installed are those which have small antennas, and thus Low Earth Orbit (LEO) systems (Iridium/Globalstar). Satellite based Communication System is being installed onboard for Iridium c or a simi-lar network (Fig. 14). A complete separation between the autopilot system and the payload system was adopted to obtain a Safe Flight configuration. A direct radio connection will be used during the critical flight phases (take-off and landing) and for system integration and testing, and an Iridium satellitebased system for longer flights off-shore. The signal from the 2.4GHz on-board R/C receiver is connected to the autopilot and a special switching mechanism inside the autopilot will allow the autopilot to be overridden by the remote control at any time, as long as the remote control transmitter is within range of the aircraft. The range of this system will be 1 to 2 km, which is suitable for the visibility range of the manual pilot. In this way, any possible malfunction of the autopilot or telemetry system is overcome and flight safety is increased to great extent. The same telemetry transceiver (radio modem) system is needed for the ground segment. In addition, a directional antenna can be used thus greatly increasing range and reliability of the data connection. The ground control station is basically composed of a PC and ground control software which is the user interface to the SESA UAV system for mission planning and runtime control. All the mission planning work is done intuitionally on an underlying map. This allows a very flexible and safe flight path design. A check with respect to the aircraft performance is done automatically to ensure a realistic and safe flight of the UAV 4. UAV Flight Demonstration for Fishery The SESA flight demo has the following characteristics: the UAV will take off from the Italian shores. (Fig. 14). 1. The UAV will be manually controlled for take off. 2. Once in the air, it will be switched to auto pilot mode until it reaches its destination. 3. The ship positions are sent to the local authorities which will programme the UAV to reach the ship coordinates 4. The target boat will be beyond line of sight and reach of RF waves, ie 20nm 5. The flying altitude will be between 150m and 300m high. 6. The flight will be entirely above water and as far as possible from the Italian coastline but within the Italian EEZ 7. The images will be transmitted continuously to the operation room (most likely a PC and antenna in a vehicle) at the take-off site. The target coordinates for the auto pilot might be updated during the flight if the ship has moved. 8. When it arrives at the ship location, the UAV will take some high resolution pictures. 9. Once the mission has been accomplished, the UAV will be reprogrammed to automatically fly back to the take-off site. 10. When the plane reaches remote control and is within the line of sight of the operator, the UAV is switched back to manual mode to be safely landed. When the UAV is at a distance of less than 5km from the GCS, a double redundancy of transmission is expected for safety reasons (both direct radio link and satellite transmission are possible for UAV control ). 11. The total duration of the flight should be around 3h, depending on the distance to shore. Two hours to take off, to get into position and to take picture and one hour to get back and land have been estimated. Talks with the Italian CAA authorities concerning flying the UAV are at present underway to obtain the Permit to Fly. Since the SESA weight is just 30kg and since it shall be used for research and scientific purposes, an EASA certificate is not necessary. Nevertheless, the following items shall be pursed: See and Avoid system on board; Flight over a non populated area (although the Maximum kinetic energy of 95 KJ shall not be reached); Direct visual manual control is necessary to obtain a safe flight and to avoid double-triple redundancy. The SESA shall be followed during the demo flight by a boat with the pilot on board for any UAV emergency remote control. If necessary the R/C can override the A/P control at any moment. No catastrophic failure condition shall result from the failure of a single component; the allowable Quantitative Probabilities (per 1 flight hour) is less than 10 6.

10 First Flight of Scaled Electric Solar Powered UAV for Mediterranean Sea Border Surveillance Forest and Fire Monitoring New fuselage sructure A new fuselage structure has been designed for a better positioning of the masses inside the fuselage and for a better centre of gravity excursion. The structure was designed to withstand the limit load of 3.8. The structure has been built by the Archemide Advanced Composite company using fibreglass rein-forced plastic for the fuse skin and carbon-fibre composite materials for a few frames, especially in the connection with the wing spar. A mould was realized for the proper layout of the fuse. The boom that connect the fuse and tails has been manufactured in carbon-fibre. The new landing gear has also been manufactured by CFRP. The new fuselage has been assembled and reported in Fig Conclusions The following conclusion can be made as a result of the many years of research in the field of solar powered UAV: HAVE-UAV can be used at least for low latitude sites in Europe and for 4-6 months continuous flight. Early Forest Fire detection, Border Patrol and Fishery monitoring would be possible at much cheaper costs and at a higher resolution than the current systems offer, and it would be obtained continuously. The very light CFRP structural elements are feasible. Good correspondence has been verified between the experimental, analytical and FEM analysis. The brushless electric motors and fuel cell systems are feasible. The preliminary flight tests of a few critical items were successively carried out, verifying the correct functioning of the new critical technologies involved in the flight: solar power production, electric system, telemetry system, flight control. 1. HELINET: Network of the Stratospheric Platforms for Traffic Monitoring, Environmental Surveillance and Broadband Services, Responsible of the HeliPlat Design and Manufacturing: Prof. G. Romeo, EC 5 FP CAPECON:Civil UAV Applications and Economic Effectivity of Potential Configuration Solutions, EC 5 FP. - WP Leader of 3 HALEs Design: Prof. G. Romeo. 3. ENFICA-FC: ENvironmentally Friendly Inter City Aircraft powered by Fuel Cells, EC-6FP AERO- 1, Ott Coordinator: Prof. G. Romeo. 4. TANGO: Telecommunications Advanced Networks for Gmes Operation, (SIP5-CT ).Coord. Eads Astrium. Polito Scientific Resp.: Prof. G. Romeo. 5. D. Cohen, 2005 Global markets for civil and commercial UAVs. Frost and Sullivan Interactive Briefing, UAVNET, available from 6. B. Curtin, Solar-Powered UAV Development for NASA. International Technical Conf. on Uninhabited Aerial Vehicles. UAV Paris, France, June J.R. Wilson, Fly like a Vulture, Aerospace America.pp , G. Romeo, Design of High Altitude Very-Long Endurance Solar-Powered Platform for Earth Observation and Telecommunication Applications, J. Aerotecnica Missili e Spazio, Vol.77, n.3-4, pp , G. Romeo, G. Frulla, E. Cestino and G. Corsino, HE- LIPLAT: Design, Aerodynamic and Structural Analysis of Very-Long Endurance Solar Powered Stratospheric UAV, AIAA Journal of Aircraft, Vol.41, n.6, pp , G. Romeo and G. Frulla, HELIPLAT: High Altitude Very- Long Endurance Solar Powered UAV for Telecommunication and Earth Observation Applications, AThe Aeronautical Journal, Vol.108, n.1084, pp , G. Romeo, G. Frulla and E. Cestino, Design of high altitude long endurance solar powered unmanned air vehicle for multi-payload and operations, Journal Of Aerospace Engineering Part G., Proc. IMechE, Vol.221, pp , I. Tuzcu, P. Marzocca, E. Cestino, G. Romeo and G. Frulla, Stability and Control of a High-Altitude-Long-Endurance UAV, Journal of Guidance, Control and Dynamics, Vol.30, n. 3, pp , G. Romeo and G. Frulla, HELIPLAT: Aerodynamic and Structural Analysis of HAVE Solar Powered Platform, Proceedings 1st AIAA Technical Conference and Workshop on Unmanned Aerospace Vehicles, Systems, Technologies and Operations, Portsmouth, VA, USA, May 20-23, G. Romeo, G. Frulla, E. Cestino and G. Corsino, HALE UAV Solar Configuration Cost Estimation. 7. Acknowledggements The authors acknowledge the important contribution of European Commission by the funding programmes [?], [?], [?] and [?]. The authors acknowledge the important contribution given by M. Francesetti and G. Correa. And of A. Motto (Archemide Advanced Composite). REFERENCES

11 18 G. Romeo, M. Pacino, F. Borello Figure 12. Telemetry wireless system and data logger. Figure 13. Telemetry wireless data display. Figure 11. Video and Thermo camera wireless system and acquisition examples. Figure 14. Possible Flight area and mission architecture.

12 First Flight of Scaled Electric Solar Powered UAV for Mediterranean Sea Border Surveillance Forest and Fire Monitoring 19 Figure 15. New SESA Fuselage