Rozprawy doktorskie: „Helicopter”

1

Perkins, Keith M. "Implementing realistic helicopter physics in 3D game environments". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02sep%5FPerkins.pdf.

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Thesis (M.S. in Modeling, Virtual Environments and Simulations)--Naval Postgraduate School, September 2002.
Thesis advisor(s). Includes bibliographical references (p. 79-80). Also available online.

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Peitso, Loren E. "Visual field requirements for precision nap-of-the-earth helicopter flight". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02sep%5FPeitso.pdf.

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Thesis (M.S. in Modeling, Virtual Environments and Simulation)--Naval Postgraduate School, September 2002.
Thesis advisor(s): Rudolph P. Darken, Joe Sullivan. Includes bibliographical references (p. 65-66). Also available online.

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Kulakowski, Walter W. "Exploring the feasibility of the virtual environment helicopter system (VEHELO) for use as an instructional tool for military helicopter pilots". Thesis, Monterey, California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/1394.

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The requirement for low-level navigation flight conducted between 200 and 500 feet above ground level is something unique to the military helicopter pilot. Each novice helicopter pilot is introduced to this skill early and in a limited number of flights or flight hours. A low situational awareness (SA)is historically noted among the novice pilots during their first few flights within this flight regime. To that end, this thesis continues with the work conducted earlier to develop a trainer that places the pilot in an immersive and familiar cockpit environment for training through the use of chromakeyed technology as employed in the Virtual Environment Helicopter System (VEHELO). The pilot will then be able to learn and exercise required piloting tasks and multi-place aircraft communications as authentically and as meticulously as in actual flight. The focus of this thesis is to continue validation of the ChrAVE/VEHELO system. This will be accomplished by comparison of data obtained from data collected by pilots flying the ChrAVE and flying the actual aircraft during initial navigational training flights. Additionally this thesis will attempt to show that the latest version of the system has a previously unrecognized ability to improve pilot performance. The system is capable of teaching novice pilots the important skill of Crew Resource Management (CRM) and the appropriate communication skills. The original Chromakey Augmented Virtual Environment (ChrAVE) helicopter flight simulation system was developed to substantiate the feasibility of having embedded trainers for helicopters. Both the ChrAVE and VEHELO are comprised of commercial off the shelf (COTS) equipment in a mobile wheeled box. To determine the effectiveness of the ChrAVE as an instructional tool, the opinions of pilots and pilot instructors will be collected for analysis. The subject pilots will be tasked with numerous realistic piloting tasks. Empirical data will be collected and evaluated according to the low-level navigation performance thresholds set forth by Marine Medium Helicopter Training Squadron 164 (HMMT- 164) which is the CH-46E Model Manager.
US Marine Corps (USMC) author.

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Howard, Christopher B. Bradley Walter Lee. "Fatigue methodology for analysis of helicopter dynamic components". Waco, Tex. : Baylor University, 2008. http://hdl.handle.net/2104/5188.

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Carico, Dean. "Helicopter controllability". Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/27077.

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Olsson, Julia, i Sophie Nilsonne. "Helicopter money". Thesis, KTH, Fastigheter och byggande, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-191551.

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This thesis has been conducted through a qualitative research method in order to explain the concept of helicopter money and how to implement it in Sweden in line with present law. Milton Frideman was the first to coin the concept of helicopter money. His theory was that a permanent increase of the monetary base via money transferring to households would increase the aggregate demand and consequently result in an increase of the inflation level. Further Ben Bernanke has developed this theory to not only include transferring money to households but to the government in order to enable an increase in public spending and increase of inflation. Helicopter money is a form of direct monetary financing, which is illegal in Sweden today. There are ways to implement it though by doing an implicit transfer to the government through purchases of treasury bonds that are held in infinity. Helicopter money therefore requires cooperation between the government and the Riksbank. In order for helicopter money to be a sufficient tool the money that are being transferred needs to be consumed. Helicopter money has the unique quality that it’s irredeemable. Which result in an asymmetric treatment of the money, which mean that households never have to repay these money and therefore the consumption propensity rises. Helicopter money also weakens the currency, which results in an increase of inflation. Transferring money to the households would probably increase the inflation level but it also entails risks. If we on the other hand transfer the money to the government we can be absolutely certain that inflation will rise. The best way to implement helicopter money in order to achieve a higher inflation and at the same time taking present law into account is therefore to make an implicit transfer to the government. A good communication and explanation of the intentions are of great importance in order to retain the trust of the government and institutions.
Denna uppsats har genom en kvalitativ undersökning redogjort för begreppet helikopterpengar samt vilka förutsättningar som krävs för att implementera det i Sverige med hänsyn till rådande lagstiftning. Helikopterpengar bygger på en teori av Milton Friedman och innebär en permanent ökning av penningmängden via en transferering till hushållen vilket resulterar i en ökad aggregerad efterfråga och stigande inflation. Begreppet har utvecklats av bland annat Ben Bernanke som menar på att en transferering av helikopterpengarna likväl kan ske till staten för att öka offentliga utgifter och på det sättet driva upp inflationen. Helikopterpengar är en typ av direkt monetär finansiering som är förbjuden i Sverige med dagens lagstiftning. Det går dock att praktiskt tillämpa helikopterpengar genom att göra en indirekt transferering till staten genom köp av statsobligationer som hålls för evigt. Helikopterpengar kräver alltså ett samarbete mellan staten och Riksbanken. För att helikopterpengar ska få önskad effekt bygger det på att pengarna konsumeras. Helikopterpengar innebär en asymmetrisk behandling av pengarna vilket gör att hushållen inte behöver betala tillbaka pengarna i framtiden och konsumtionsbenägenheten ökar. Helikopterpengar urholkar kronans värde vilket leder till en svagare valuta som i sin tur också bidrar till en ökad inflation. En transferering till hushållen skulle med stor sannolikhet ge effekt på inflationsnivån men medför även risker. Genomförs däremot en transferering till staten kommer inflationen med säkerhet att öka då staten kan se till att varje krona spenderas. Bästa sättet att implementera helikopterpengar för att få störst effekt med hänsyn till rådande lagstiftning är alltså att göra en indirekt transferering till staten. Det är även viktigt att kommunicera intentionerna på ett pedagogiskt sätt för att marknaden ska behålla förtroendet för pengar och institutionerna.

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Ference, Edward W. "Case study of the development of the Apache attack helicopter (AH-64)". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02Dec%5FFerence.pdf.

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Thesis (M.S. in Program Management)--Naval Postgraduate School, December 2002.
Thesis advisor(s): Michael W. Boudreau, Richard G. Rhoades. Includes bibliographical references (p. 63-65). Also available online.

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Zhao, Jinggen. "Dynamic Wake Distortion Model for Helicopter Maneuvering Flight". Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7103.

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A new rotor dynamic wake distortion model, which can be used to account for the rotor transient wake distortion effect on inflow across the rotor disk during helicopter maneuvering and transitional flight in both hover and forward flight conditions, is developed. The dynamic growths of the induced inflow perturbation across the rotor disk during different transient maneuvers, such as a step pitch or roll rate, a step climb rate and a step change of advance ratio are investigated by using a dynamic vortex tube analysis. Based on the vortex tube results, a rotor dynamic wake distortion model, which is expressed in terms of a set of ordinary differential equations, with rotor longitudinal and lateral wake curvatures, wake skew and wake spacing as states, is developed. Also, both the Pitt-Peters dynamic inflow model and the Peters-He finite state inflow model for axial or forward flight are augmented to account for rotor dynamic wake distortion effect during helicopter maneuvering flight. To model the aerodynamic interaction among main rotor, tail rotor and empennage caused by rotor wake curvature effect during helicopter maneuvering flight, a reduced order model based on a vortex tube analysis is developed. Both the augmented Pitt-Peters dynamic inflow model and the augmented Peters-He finite state inflow model, combined with the developed dynamic wake distortion model, together with the interaction model are implemented in a generic helicopter simulation program of UH-60 Black Hawk helicopter and the simulated vehicle control responses in both time domain and frequency domain are compared with flight test data of a UH-60 Black Hawk helicopter in both hover and low speed forward flight conditions.

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9

Law, N. "Integrated helicopter survivability". Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/6518.

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A high level of survivability is important to protect military personnel and equipment and is central to UK defence policy. Integrated Survivability is the systems engineering methodology to achieve optimum survivability at an affordable cost, enabling a mission to be completed successfully in the face of a hostile environment. “Integrated Helicopter Survivability” is an emerging discipline that is applying this systems engineering approach within the helicopter domain. Philosophically the overall survivability objective is ‘zero attrition’, even though this is unobtainable in practice. The research question was: “How can helicopter survivability be assessed in an integrated way so that the best possible level of survivability can be achieved within the constraints and how will the associated methods support the acquisition process?” The research found that principles from safety management could be applied to the survivability problem, in particular reducing survivability risk to as low as reasonably practicable (ALARP). A survivability assessment process was developed to support this approach and was linked into the military helicopter life cycle. This process positioned the survivability assessment methods and associated input data derivation activities. The system influence diagram method was effective at defining the problem and capturing the wider survivability interactions, including those with the defence lines of development (DLOD). Influence diagrams and Quality Function Deployment (QFD) methods were effective visual tools to elicit stakeholder requirements and improve communication across organisational and domain boundaries. The semi-quantitative nature of the QFD method leads to numbers that are not real. These results are suitable for helping to prioritise requirements early in the helicopter life cycle, but they cannot provide the quantifiable estimate of risk needed to demonstrate ALARP. The probabilistic approach implemented within the Integrated Survivability Assessment Model (ISAM) was developed to provide a quantitative estimate of ‘risk’ to support the approach of reducing survivability risks to ALARP. Limitations in available input data for the rate of encountering threats leads to a probability of survival that is not a real number that can be used to assess actual loss rates. However, the method does support an assessment across platform options, provided that the ‘test environment’ remains consistent throughout the assessment. The survivability assessment process and ISAM have been applied to an acquisition programme, where they have been tested to support the survivability decision making and design process. The survivability ‘test environment’ is an essential element of the survivability assessment process and is required by integrated survivability tools such as ISAM. This test environment, comprising of threatening situations that span the complete spectrum of helicopter operations requires further development. The ‘test environment’ would be used throughout the helicopter life cycle from selection of design concepts through to test and evaluation of delivered solutions. It would be updated as part of the through life capability management (TLCM) process. A framework of survivability analysis tools requires development that can provide probabilistic input data into ISAM and allow derivation of confidence limits. This systems level framework would be capable of informing more detailed survivability design work later in the life cycle and could be enabled through a MATLAB® based approach. Survivability is an emerging system property that influences the whole system capability. There is a need for holistic capability level analysis tools that quantify survivability along with other influencing capabilities such as: mobility (payload / range), lethality, situational awareness, sustainability and other mission capabilities. It is recommended that an investigation of capability level analysis methods across defence should be undertaken to ensure a coherent and compliant approach to systems engineering that adopts best practice from across the domains. Systems dynamics techniques should be considered for further use by Dstl and the wider MOD, particularly within the survivability and operational analysis domains. This would improve understanding of the problem space, promote a more holistic approach and enable a better balance of capability, within which survivability is one essential element. There would be value in considering accidental losses within a more comprehensive ‘survivability’ analysis. This approach would enable a better balance to be struck between safety and survivability risk mitigations and would lead to an improved, more integrated overall design.

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10

Sadownick, Ronald 1960. "Helicopter configuration optimization". Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/82683.

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Thesis (S.M.)--Massachusetts Institute of Technology, System Design & Management Program, February 2001.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (leaf 102).
by Ronald Sadownick.
S.M.

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11

Morgans, Aimee Sian. "Transonic helicopter noise". Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615704.

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Leusink, Debbie. "Advanced numerical tools for aerodynamic optimization of helicopter rotor blades". Thesis, Paris, ENSAM, 2013. http://www.theses.fr/2013ENAM0010.

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La conception aérodynamique des pales du rotor principal d’un hélicoptère doitsimultanément prendre en compte plusieurs objectifs relatifs aux critères du vol stationnaire etvol d’avancement. Cette thèse vise à développer une boucle d’optimisation automatiséecombinant des algorithmes d’optimisation avancés et des outils de simulation. Deux outils desimulation sont employés pour la prédiction des performances rotor : le code de mécanique devol HOST, ainsi que le code de Mécanique des Fluides Numérique (MFN) elsA. Une analyse deces outils est effectuée pour des cas test bien documentés afin d’estimer leur capacité à prédiredes tendances de performances rotor en fonction de la géométrie de pale. L’influence desparamètres numériques est également caractérisée. Aussi, une stratégie d’optimisation estdéveloppée, permettant la prise en compte de plusieurs objectifs et de contraintes complexes,ainsi que la détermination d’optima globaux pour ce problème multimodale. Suivant cescritères, un algorithme génétique (AG) est sélectionné. Afin de réduire le nombre d’évaluationsnécessaires, une stratégie d’optimisation multi-fidélité est proposée : une optimisationpréliminaire utilisant l’AG et HOST est utilisée pour la réduction de l’espace des paramètres ensélectionnant la zone de haute performance. Ensuite, une surface de réponse est construiteavec des calculs haute-fidélité des pales de haute performance comme vu par l’étapepréliminaire. L’optimisation est finalement effectuée sur cette surface de réponse haute-fidélité.L’approche proposée résulte en une augmentation significative des performances rotor, tout enrespectant le critère industriel relatif au nombre de calculs coûteux comme MFN. L’approcheproposée se révèle être un outil efficace pour la conception de pales du rotor principald’hélicoptère
The aerodynamic design of helicopter rotor blades requires taking into accountedmultiple objectives simultaneously, to provide a compromise solution for the conflictingrequirements associated to hover and forward flight conditions. The present work aims atdeveloping an automated optimization based on the combination of advanced optimizationalgorithms and simulation tools. As a preliminary step, candidate simulation methods andoptimization algorithms are assessed in detail. Two simulation methods are employed for thecomputation of rotor performance: the in-house Helicopter Overall Simulation Tool (HOST),based on the blade element method, and ONERA’s Computation Fluid Dynamics (CFD) codeelsA. An in-detail analysis of both simulation tools for well documented test cases is carried out,with focus on their capability of predicting trends of the global rotor performance as a function ofblade geometry. The impact of computation settings is also characterized. Then, an optimizationstrategy is developed, allowing the incorporation of multiple objectives and complex constraints,and the detection of global optima for multi-modal problems. Based on these criteria, a geneticalgorithm (GA) is selected. To reduce the number of simulations required to find optimalsolutions, a Multi-Fidelity Optimization (MFO) strategy is proposed: a preliminary low-fidelity GAoptimization stage based on HOST simulations is used to reduce the design space by selectinga high-performance subspace. Then, a CFD-based surrogate model is constructed on thereduced design space by using a sample of high-performance blade from the low-fidelity step.The final optimization step is run on the high-fidelity surrogate. The proposed MFO approachresults in significant rotor performance improvements while using a far lower number of costlyCFD evaluations of the objective functions with respect to a full GA optimization. The proposedapproach is shown to represent an efficient design tool for industrial helicopter rotor blade

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Bru, Leif Hamang. "Autonomous Remote Controlled Helicopter". Thesis, Norwegian University of Science and Technology, Department of Computer and Information Science, 2005. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9199.

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Unmanned Aerial Vehicles (UAVs) have a tremendous appeal. One can imagine a large number of applications such as search-and-rescue, traffic monitoring, aerial mapping, etc. Helicopters are particularly attractive due to their Vertical Take Off and Landing (VTOL) capabilities. The research on UAVs has shown rapid development in recent years, and offers a great number of challenges. This thesis is the result of a project which is a part of the Autonomous Remote Controlled Helicopter (ARCH) project at the Department of Computer and Information Science, Norwegian University of Science and Technology. The ARCH project has already gained public interest, when it was featured on a television program (Schrödingers katt, NRK. September 2004). The object of this thesis is divided into three main sections. Firstly, it is to create and describe a remote control system for controlling the UAV in semi-autonomous mode, that will also enable the UAV to autonomously follow objects (pursuit-mode). Secondly, it is to create and describe a virtual cockpit which is to be used with the remote control system. Finally, it is to create and describe an image stabilization system, which can stabilize the visual information sent from the UAV to the ground and the virtual cockpit. These three components have been combined and integrated into the client prototype called ARCH Groundstation. Together, these three components provides a platform for an operator to control the ARCH UAV in semi-autonomous mode.

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Kenyon, Adam Richard. "Helicopter Rotor- Fuselage Aerodynamic Interactions". Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499021.

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Prince, Martyn Paul. "Stabilising ships for helicopter operations". Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342777.

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Adamson, Alan, i Albert Berdugo. "Helicopter Slip Ring Replacement System". International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/604271.

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ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California
Most helicopter programs require the acquisition of parameters from the rotating systems. Historically, these systems made use of electromechanical slip rings for the transfer of power, control, and data from within the helicopter's cabin to the rotating hardware. Slip rings are primarily used in dedicated instrumentation vehicles and are not commonly used in production platforms that may require instrumentation of the rotating systems for in-service load and fatigue monitoring. Additionally, the use of slip rings requires time and money to integrate the hardware and equipment into the aircraft in order to perform rotor data acquisition. The time needed to perform modifications to transmissions and drive trains plays a big factor in the increased costs of aircraft development. Less intrusive installations would minimize the need for mechanical changes and would improve the time needed to install the instrumentation. This paper describes a wireless system approach to perform the test without the slip ring, and provides performance data that validates this new method of instrumenting unobtrusively to save time and money without sacrificing data integrity.

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Elias, Joerg. "Advanced integrated helicopter flight simulator cockpit design". Thesis, Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/12469.

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Kadmiry, Bourhane. "Fuzzy Control for an Unmanned Helicopter". Licentiate thesis, Linköping University, Linköping University, AUTTEK - Autonomous Unmanned Aerial Vehicle Research Group, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-5723.

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The overall objective of the Wallenberg Laboratory for Information Technology and Autonomous Systems (WITAS) at Linköping University is the development of an intelligent command and control system, containing vision sensors, which supports the operation of a unmanned air vehicle (UAV) in both semi- and full-autonomy modes. One of the UAV platforms of choice is the APID-MK3 unmanned helicopter, by Scandicraft Systems AB. The intended operational environment is over widely varying geographical terrain with traffic networks and vehicle interaction of variable complexity, speed, and density.

The present version of APID-MK3 is capable of autonomous take-off, landing, and hovering as well as of autonomously executing pre-defined, point-to-point flight where the latter is executed at low-speed. This is enough for performing missions like site mapping and surveillance, and communications, but for the above mentioned operational environment higher speeds are desired. In this context, the goal of this thesis is to explore the possibilities for achieving stable ‘‘aggressive’’ manoeuvrability at high-speeds, and test a variety of control solutions in the APID-MK3 simulation environment.

The objective of achieving ‘‘aggressive’’ manoeuvrability concerns the design of attitude/velocity/position controllers which act on much larger ranges of the body attitude angles, by utilizing the full range of the rotor attitude angles. In this context, a flight controller should achieve tracking of curvilinear trajectories at relatively high speeds in a robust, w.r.t. external disturbances, manner. Take-off and landing are not considered here since APIDMK3 has already have dedicated control modules that realize these flight modes.

With this goal in mind, we present the design of two different types of flight controllers: a fuzzy controller and a gradient descent method based controller. Common to both are model based design, the use of nonlinear control approaches, and an inner- and outer-loop control scheme. The performance of these controllers is tested in simulation using the nonlinear model of APID-MK3.

Report code: LiU-Tek-Lic-2002:11. The format of the electronic version of this thesis differs slightly from the printed one: this is due mainly to font compatibility. The figures and body of the thesis are remaining unchanged.

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Trentini, Michael. "Mixed norm control of a helicopter". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0034/NQ38512.pdf.

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Seggerty, Ryan L. "MUOS: application in naval helicopter operations". Thesis, Monterey, California: Naval Postgraduate School, 2015. http://hdl.handle.net/10945/45255.

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Approved for public release; distribution is unlimited
The Mobile User Objective System (MUOS) is the next generation of military satellite communications technology. Using a unique combination of satellite vehicles and radio access facilities, MUOS allows the end user unparalleled access to the global information grid (GIG) with a significant increase in voice and data capacity over legacy UFO systems. Leveraging current WCDMA technology used by commercial cellular companies, the MUOS system will allow uninterrupted communications worldwide. This research aims to identify gaps in existing naval helicopter network capabilities and how to apply MUOS to further increase operational effectiveness. Current and legacy helicopter platforms were analyzed regarding connectivity in a network centric environment. Using simple modeling techniques in order to reduce the throughput of the user terminal to 16 kbps enabled a simulation of load times of various Internet applications. Analyzing the load times of web applications gives an initial indication of the viability of MUOS in the rotary wing environment. Even when reduced to a throughput of 16 kbps, many of the applications would still be usable in benign flight regimes. Text- or chat-based applications will see the biggest benefit from MUOS technology, allowing aircrews to quickly disseminate information anywhere in the world.

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Ling, Gustav, i Jesper Persson. "Propulsion Unit of a 3DOF Helicopter". Thesis, Linköpings universitet, Fluida och mekatroniska system, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-120799.

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This Bachelor thesis is a part of a bachelor project which includes building, programming and controlling a 3DOF tandem helicopter. This particular report deals with the propulsion units, i.e. the motors and propellers of the helicopter. It covers the process of how to determine the most suitable propulsion units for the rig that eventually will enable it to run. To achieve this, different data have been processed. Torque and thrust are two important parameters that have been studied. The data have been acquired by different tests, e.g. thrust measurements from a thrust rig. Also more complex analysis such as Blade Element Theory and Actuator Disk Theory have been carried out in order to determine the behaviour of the propulsion units. Study data sheets and databases was also a part of the work. The result of this work was two equal propulsion units which were mounted in the helicopter. They proved to work satisfactory and provided wanted dynamics to the system.
Design & Implementation of a 3DOF Helicopter

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Hay, Melissa Constance. "Noise Exposure in Medical Helicopter Flights". Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4331.

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The purpose of this project was to evaluate noise exposures of helicopter pilots, nurses and paramedics at a hospital by collecting area and personal samples, determining noise levels inside the helmet, and evaluating the current selection of personal protective equipment (PPE). Measurements gathered during personal sampling were statistically analyzed and calculated using OSHA 1910.95 App A to determine dose, reference duration and the Time-Weighted Average (TWA). Using a mannequin head, with the noise dosimeters in the ears, tests were performed on the headset inside the helmets to determine the sound pressure levels generated from the radio communications at different volume levels. According to our results, the crew is not exposed to hearing levels above the OSHA permissible exposure limit (PEL), because their flight times are usually only 20-30 minutes and the dose not above 22% of the OSHA limit. If the total flight times were 6.5 hours or more, the crew could be above the OSHA PEL. Testing the helmet speakers resulted in a recommendation that the setting not be set above the 6 o'clock position so that the crew would not be exposed to sound pressure levels about 80 dBA

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Farhat, M. A. "Engineering a miniature remotely piloted helicopter". Thesis, University of Sussex, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372718.

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Lawes, Stephen Thomas. "Real-time helicopter modelling using transputers". Thesis, University of York, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241015.

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Keener, Joseph Kristopher 1975. "The helicopter innovation in Army aviation". Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8777.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Political Science, 2001.
Includes bibliographical references (p. 79-82).
This study was performed to test competing theories of innovation for their explanatory power in describing the series of innovations in United States Army aviation centered on the helicopter. The theories of strategic threat, civilian intervention, and inter service rivalry were applied to the innovations of air mobility, the anti-tank helicopter, and recent developments in Army doctrinal thought. This study found that while strategic threat and inter-service rivalry theories provided adequate explanation for the developmental phases of the innovation, only civilian intervention could fully explain the implementation of these innovations into Army force structure.
by Joseph Kristopher Keener.
Ph.D.

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Spangler, Ronald L. 1964. "Piezoelectric actuators for helicopter rotor control". Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/14462.

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Eren, Perk Barıṣ. "Control primitives for fast helicopter maneuvers". Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/38283.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.
Includes bibliographical references (leaves 77-82).
In this paper, we introduce a framework for learning aggressive maneuvers using dynamic movement primitives (DMP) for helicopters. Our ultimate goal is to combine these DMPs to generate new primitives and demonstrate them on a 3-DOF (3 Degrees of Freedom) helicopter. An observed movement is approximated and regenerated using DMP methods. After learning the movement primitives, the partial contraction theory is used to combine them. We imitate the aggressive maneuvers that are performed by a human and use these primitives to achieve new maneuvers that can fly over an obstacle. Experiments on the Quanser 3-DOF Helicopter demonstrate the effectiveness of our proposed method. In addition, we linearly combine DMPs and propose a new type of DMP. We also analyze Matsuoka's oscillator and Hopf oscillator using contraction theory.
by Barıṣ Eren Perk.
S.M.

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28

Daigh, Sara L. (Sarah Louise) 1981. "Helicopter final assembly critical path analysis". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/73413.

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Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; in conjunction with the Leaders for Global Operations Program at MIT, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 53).
Helicopter final assembly involves the installation of hundreds of components into the aircraft and takes thousands of man-hours. Meeting production targets such as total build days and total aircraft man-hours can be difficult when faced with challenges related to parts, workforce, and scheduling. A tool to identify key installations on which to focus efforts for maximum benefit can help improve performance to targets. The Critical Path Method was developed as a project management tool to aid in scheduling large and complex projects. Its application to manufacturing can provide the insights necessary to improve performance in an environment such as helicopter final assembly. This thesis provides a case study of helicopter final assembly. A critical path analysis is performed on the assembly process, using predecessor, duration, and resource data. The results of the analysis are used to draw conclusions about the system as a whole and to make recommendations to improve system performance.
by Sarah L. Daigh.
S.M.
M.B.A.

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Trott, Christian A. (Christian Alan). "Electronics design for an autonomous helicopter". Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43573.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.
Includes bibliographical references (p. 158).
by Christian A. Trott.
M.Eng.

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30

Orchard, Matthew Noel. "Optimisation of the compound helicopter configuration". Thesis, University of Southampton, 2000. https://eprints.soton.ac.uk/47096/.

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Pomfret, Andrew James. "Eigenstructure assignment for helicopter flight control". Thesis, University of York, 2006. http://etheses.whiterose.ac.uk/21053/.

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Traditional approaches to helicopter control law design involve the iterative application of single-input, single-output loop-at-a-time classical methods. Helicopters are typically highly cross-coupled systems, and such approaches become very laborious under these conditions. Modern multi variable techniques, despite their ability to solve control design problems very efficiently, have not been embraced by practitioners. One possible reason for this is the lack of design visibility provided by such techniques, in terms of performance and controller structure. This thesis presents new observations and algorithms which address this problem. Eigenstructure assignment is introduced in the context of classical control in order to illustrate the extent to which the two methodologies share a common language of expression. The sources of the primary dynamics of a helicopter are identified, and a new ideal eigenstructure is derived which fulfills the UK Def.Stan.00-970 handling qualities specification. Dynamic compensators are investigated in detail, to identify the distribution of the design freedom added by these structures and its possible uses in the context of eigenstructure assignment. It is found that the manner in which the freedom is expressed does not lend itself to eigenstructure assignrrient, and so other sources of design freedom are sought. This leads to the development of two novel algorithms, and several extensions, for the assignment of eigenstructure to systems with a direct transmission term and consequently to helicopters with acceleration feedback or proportional-plus-derivative control structures. The use of design freedom remaining after eigenstructure assignment is considered, and an algorithm for using it to impose structure on the controller without affecting the assigned eigenstructure is developed. Finally all of the algorithms developed in the thesis, along with the ideal eigenstructure, are demonstrated by application to a linearised helicopter model.

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32

Buysschaert, Frank. "Helicopter power transmission : changing the paradigm". Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/386149/.

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In the conventional helicopter, the transmission and powerplant systems are the major production and operator direct operating cost drivers. Additionally, they are related to helicopter safety and reliability concerns and impose performance boundaries. As a consequence, they need to be addressed. Adapting the transmission and powerplant systems with the introduction of more electric technologies, which are reported to be more reliable and cost friendly, involves a gross weight penalty, which cannot be accepted from a performance viewpoint. The implementation of liquid hydrogen, with the objective to introduce a sustainable energy carrier and free cold source for the high temperature superconductive devices driving the tail rotor, appears unattractive, from either a weight or a exploitation standpoint. Biodiesel could be an alternative to Avgas driven configurations, but at the moment, it has questionable chemical characteristics and is therefore discarded. Conceptual alternatives to the conventional helicopter explored in an attempt to verify their ability to overcome the stated performance, safety and cost aspects, are subjected to the same problems, the Turbine Driven Rotor (TDR) helicopter configuration excepted. The TDR helicopter drives a coaxial rotor configuration by means of a rotor embedded Ljungstr¨om turbine, omitting the need for a mechanical transmission system. Three TDR helicopter thermodynamic cycles are proposed. The piston engine powered TDR cycle shows to be of interest for the low weight class helicopters. The turbofan powered TDR cycle is preferred in the mid and high weight categories, benefitting from its configurational simplicity. The more complex turboshaft powered TDR cycle requires a heat exchanger, is heavier and thus not recommended. With respect to the Ljungstrom turbine, the loss models of Soderberg and Ainley and Mathieson used to establish its geometry and performance characteristics are generally acceptable and appear coherent, while a deviation angle correction is developed to cope with the radial outflow configuration of the turbine. Similarly, loss models for the internal leakage and disk friction are proposed. However, these models could not be substantiated by means of experiments. A design methodology to implement the Ljungstrom turbine in the helicopter rotor head is presented and allows adjusting the thermodynamic cycle characteristics such as to maximise the performance gain with respect to the conventional helicopter. For nominal operating conditions, ISA SLS, a VLR-class TDR helicopter shows to bear a performance gain of 10% over a conventional helicopter when equipped with an Avgas engine and 14% when a Diesel engine is used. Hereby, the cycle pressure ratio remained low, i.e. approximately 1.25, allowing a turbine polytropic effciency of 87%. An identical study with a NH-90-class TDR helicopter proved to offer a performance potential of 50% at a cycle pressure ratio around 1.6 and a turbine polytropic effciency of 90%. In all cases, the gas temperature at the inlet of Ljungstrom turbine remained below the rotor bearing temperature limit of 400 K.

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33

Horcher, Andy. "Improving Helicopter Yarding with Onboard GPS". Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/26678.

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Despite its relatively high cost, helicopter yarding has become a common means of timber extraction where site sensitivity, access, or regulations limit the use of less costly alternatives. The high costs associated with helicopter yarding, as well as the desire to expand the application of this system to extract lower value timber, increases the need for innovation to improve the operations. The cost or benefit of a particular harvest prescription or innovative technique is commonly assessed with a time and motion study. Capturing time study data require additional personnel or an imposition on the operator to record additional information. Onboard GPS can reduce or eliminate the need for additional personnel and/or operator input providing a rapid means of assessing and improving helicopter operations. This research employed onboard GPS in helicopter yarding to assess the potential of developing time studies using GPS data. Three helicopter models were sampled on a total of nine sites. Three of the sites have both experienced and inexperienced pilot data. Hemispherical canopy images were sampled at three sites. This complement of data permitted the following analysis: assessment of differences between experienced and inexperienced pilots, assessment of canopy cover on hook time, and the development of production models. The results indicate onboard GPS and the automated processing methods are suitable for creating time study data. Specifically, in all three case studies quantitative results were obtained, analyzed and opportunities for improvement identified. The time penalty suffered from using inexperienced pilots created 64 to 94% additional turn time. Increasing canopy cover correlated with increased hook time at two sites for the zenith angle segment 0 â 15Â°. Regressions assessing production show distance, slope, and choker delivery to be significant. This research shows the combination of onboard GPS, the automation process, and commonly collected turn information presents a number of opportunities, enabling the assessment of a wide range of helicopter yarding conditions.
Ph. D.

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34

Oktay, Tugrul. "Constrained Control of Complex Helicopter Models". Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/26619.

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Complex helicopter models that include effects typically ignored in control models, such as an analytical formulation for fuselage aerodynamics, blade lead-lagging and flexibility, and tail rotor aerodynamics, are derived. The landing gear, horizontal tailplane, a fully articulated main rotor, main rotor downwash, and blade flapping are also modeled. The modeling process is motivated by the desire to build control oriented, physics based models that directly result in ordinary differential equations (ODE) models which are sufficiently rich in dynamics information. A physics based model simplification procedure, which is called new ordering scheme, is developed to reduce the number of terms in these large nonlinear ODE models, while retaining the same number of governing equations of motion. The resulting equations are trimmed and linearized around several flight conditions (i.e. straight level flight, level banked turn, and helical turn) using Maple and Matlab. The resulting trims and model modes are validated against available literature data. The linearized models are first used for the design of variance constrained controllers with inequality constraints on outputs or inputs, output variance constrained controllers (OVC) and input variance constrained controllers (IVC), respectively. The linearized helicopter models are also used for the design of online controllers which exploit the constrained model predictive control (MPC) theory. The ability of MPC to track highly constrained, heterogeneous discontinuous trajectories is examined. The performance and robustness of all these controllers (e.g. OVC, IVC, MPC) are thoroughly investigated with respect to several modeling uncertainties. Specifically, for robustness studies, variations in the flight conditions and helicopter inertial properties, as well as blade flexibility effects, are considered. Furthermore, the effectiveness of adaptive switching between controllers for the management of sensor failure during helicopter operations is studied using variance constrained controllers. Finally, the simultaneous design of the helicopter and control system is examined using simultaneous perturbation stochastic approximation in order to save active control energy.
Ph. D.

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35

Arlinghaus, Mark C. "Autopilot Development for an RC Helicopter". Wright State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=wright1259002743.

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36

Mannchen, Thomas. "Helicopter vibration reduction using robust control". [S.l. : s.n.], 2003.

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Shropshire, David Richard 1950. "Feasibility of a helicopter commuter service". Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277179.

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The feasibility of intercity helicopter service has been demonstrated at several locations in North America. To study the feasibility of a helicopter service in the Phoenix-Tucson corridor, the travel time and cost characteristics of a proposed helicopter service were compared to the characteristics of existing travel modes in the corridor. Helicopter service travel times were developed using current helicopter performance data and an assumption that heliports would be located in the central business districts of each city. Helicopter service travel cost (fare) was developed using the break-even analysis relating operating cost to demand revenue. From the comparative analysis, significant travel time savings would result with a helicopter service if demand exists between the heliport locations and heliport access times are negligible. However, any travel time savings were offset by significant higher travel costs for the helicopter service when compared with the travel costs of existing modes.

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38

Tafoya, Keirsten Breann. "Process Improvement of Surface Preparation of Structuraly Bonded Helicopter Detail Parts". Thesis, University of North Texas, 2018. https://digital.library.unt.edu/ark:/67531/metadc1404599/.

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The objective of this study was to increase the bond strength at the surface interface of a thin stainless-steel panel for structural bonding on a helicopter. To achieve this objective, six activation methods for applying the coating to the panel in the surface preparation process are presented and explored. Adhesion and roughness tests were conducted to determine which method consistently initiates the etch and improves the bond at the surface. Based on the test results, three methods proved to be effective in initiating the etch. Of the three effective methods, only one method exhibited significantly improved bond strength at the surface interface as well as consistently initiated the etch in solution. The applicability of this method is discussed, and recommendations are presented for further study.

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39

Bodin, Erik, i Fanny Stenholm. "Modelling & Control of a 3DOF Helicopter". Thesis, Linköpings universitet, Fluida och mekatroniska system, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-119614.

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The scope of this report is the development of a mathematical model and a control system for a three degrees of freedom (3DOF) helicopter rig. This 3DOF-system offers a good simplification of a real world tandem helicopter for evaluating performanceof different automatic control principles. A mathematical model of the system is developed using free-body diagrams. This mathematical model is then linearized and a controller is developed by decoupling the system. Due to model imperfections external disturbances and similar effects integral action is added as well as feed-forward compensation to reduce nonlinear effects. After the controller has been decoupled the two different controllers are tuned. The Linear-Quadratic Regulator, described in section 3.6, is used for selectingstate-feedback gains. Due to the highly nonlinear nature of the system an Extended Kalman Filter is developed to estimate unmeasurable states. The model and controller is then implemented on the actual rig and evaluated. The results displayed that the elevation controller had good performance. The travel controller also showed good performance but not as good as the elevation controller. The main goal of this thesis was to develop a controller for the 3DOF helicopter system. The results clearly show that an LQR-controller is able to successfully control a system like this with decent performance characteristics despite the highly nonlinear system.

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40

Barron, James Richard. "Improving finite element methods for fabricated structures". Thesis, Imperial College London, 2000. http://hdl.handle.net/10044/1/8022.

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41

Wright, George T. "Helicopter Urban Navigation Training using virtual environments". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2000. http://handle.dtic.mil/100.2/ADA379671.

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Ercin, Gulsum Hilal. "Flight Simulation And Control Of A Helicopter". Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610194/index.pdf.

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In this thesis the development of a nonlinear simulation model of a utility helicopter and the design of its automatic flight control system is addressed. In the first part of this thesis, the nonlinear dynamic model for a full size helicopter is developed using the MATLAB/SIMULINK environment. The main rotor (composed of inflow and flapping dynamics parts), tail rotor, fuselage, vertical stabilizer, horizontal stabilizer of the helicopter are modeled in order to obtain the total forces and moments needed for the flight simulation of the helicopter. Total forces and moments are used in 6 degrees of freedom equations of motion model and helicopter states are calculated for the specified flight conditions such as hover and forward flight. Trim and linearization programs are developed. The linearized models of hover and forward flight conditions are used for the automatic flight control system design. Automatic flight control system model consists of necessary systems in order to ease the pilot control of the helicopter. A classical inner stability loop and outer flight directory mode approach is taken to design the automatic flight control system. For the inner stability loop both classical rate feedback and truncated system state feedback control approaches are used. The outer loop modes implemented are heading hold, attitude hold (pitch, roll), altitude acquire and hold mode for hover condition and heading hold, attitude hold (pitch, roll), altitude acquire and hold mode and airspeed hold for forward flight condition. Finally, the success of the controllers are demonstrated through nonlinear simulations for different flight directory modes in hover and forward flight conditions.

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Ingvaldsen, Ola Naalsund. "Power Efficient Video Communication for Mini Helicopter". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elektronikk og telekommunikasjon, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11458.

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In this thesis, a video communication system for use in a mini helicopter is reviewed. The transmitter is located in a small battery powered mini helicopter, weighing about 15 grams, and the receiver is the helicopter's remote control. The operator controls the helicopter only based on the video feed sent from the helicopter, hence it is critical that the delay is kept to a minimum. Due to the helicopter's small size, the energy available is very limited, and both coding and transmission should be efficient and have low complexity. Since processing takes considerable less energy than transmission, compressing the video is an important factor to reduce the needed transmission rate. Video compression is done using three-dimensional DPCM with motion compensation. The prediction is done around the channel noise; hence, the system uses joint source channel coding. The analog system utilizes the feedback channel already needed for closed loop DPCM to transmit every sample in an iterative fashion which expands the bandwidth to reduce transmission power. The simulations shows that for an ideal feedback channel and with a Gaussian distributed input, the system acts according to OPTA.The system is simulated in different environments and components are added to the system to make the simulations more realistic and the system more robust. The sampling period of the system with a bandwidth expansion of three is 288 ns, and with a carrier frequency of 2.39 GHz, it is reasoned that this would give flat fading in an indoor office environment.When flat fading is introduced, channel estimation and diversity are implemented to reduce the degradation caused by fading, and by adding three-dimensional DPCM, the system becomes very robust against the fast channel fluctuations caused by multipath fading. Further, in fading the iterative system experiences graceful degradation, meaning the system does not break down below a certain power but has a steady decrease in performance for decreasing Ep/No. The system shows good results (received PSNR greater than 40 dB) for an average Ep/No of 3.5 dB in the receiver, averaged over all test inputs.Simulations shows a substantial gain in lowering of the variance of the transmitted signal by video compression. For high Ep/No, the transmission power can be reduced by 17 dB to yield the same result as with no compression.

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44

Clark, Gary A. "Helicopter handling qualities in degraded visual environments". Thesis, University of Liverpool, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486093.

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New generation military helicopters are required to fly Nap-of-the-Earth (NoE) roles at night and in poor weather conditions. In these situations the pilot must guide the aircraft through obstacle cluttered environments, retain sufficient stabilised ' control, while at the same time coping with a range of degraded visual conditions. The Useable Cue Environment (UCE) procedures provide a means of assessing handling qualities as a function of available visual information, subsequently suggesting minimum control requirements (Response Types) in order to aid the pilot with the stabilisation of the aircraft. While the UCE procedures are' the preferred industry standard for quantifying and maintaining good levels of handling qualities in DVE, there is no direct appreciation of the difficulties encountered with guiding the aircraft or avoiding obstacles. The aim of this study was to develop the UCE approach by incorporating the guidance function of piloting, subsequently enriching the 'Helicopter Handling Qualities in Degraded Visual Environments' analysis procedures. To date few investigations have taken place to determine how the pilot guides the aircraft at low level and through cluttered environments. Recent studies in this field, involving the University of Liverpool, have suggested the importance of the movement of objects and textures in the visual scene (optical flow) for such prospective flight control. The most recent incarnation of this theory introduces the importance of a parameter called tau, ' , a natural temporal means of control thought to be exercised by animals and humans. '-theory provided a starting point for this investigation, developing into a series of piloted simulation trials to examine guidance based manoeuvring. Using a few carefully selected visual degradations, this extensive simulation campaign helped to identify the important visual information for guidance, such as the visual flow quality and the temporal range through which the pilot can see in order to plan his way through a cluttered environment. These findings have been translated into new UCE limits and overlaid onto the existing UCE chart. Added to these handling qualities prediction methods, a pilot control strategy for performing each of the manoeuvres has been developed using the principles of ' coupling. The possible use of this ,,-based control has been explained through the conceptual design of a tunnel-in-the-sky type flight director.

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Haycock, Bruce Charles. "Development of a helicopter emergency maneuvers trainer". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62891.pdf.

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Hansén, Rasmus, Axel Ringh, Victoria Svedberg i Nils Landin. "Autonomus Helicopter Landing on a Mobile Platform". Thesis, KTH, Optimeringslära och systemteori, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105551.

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In this thesis we investigate the problem of landing a helicopter autonomously on a mobile platform by designing controllers for the attitude- and translational dynamics in parallel. A mathematical model of the helicopter, in form of general 6-degrees-of-freedom rigid-body dynamics with application-specific actuations, is developed. A linearized model is used in order to make a landing problem more tractable, which is also rather reasonable under landing constraints, where small angle- and velocity approximations are valid. The inputs used for the attitude controller are the tail rotor thrust and the tip-path-plane angles. Then, a form of cascaded control is adopted for the translational dynamics, in which the inputs are the Euler angles together with the main rotor thrust. The resulting control system is tested by MATLAB simulations against a smooth position reference path, with satisfying results. For the landing scenario, a trajectory planning strategy based on linear model predictive control (MPC) is adopted. The cascaded control system is then used to track the translational reference trajectory. The translational reference trajectory is chosen such that the attitude dynamics is adapted to the attitude of the platform at touch-down.
Den här uppsatsen undersöker problemet att autonomt landa en modellhelikopter på en mobil plattform genom att använda olika regulatorer för attityd- och translationsdynamiken. Den matematiska beskrivningen av helikoptern utgår från dynamiken för en stel kropp med 6 frihetsgrader. Eftersom landning kan genomföras med låga hastigheter och små vinklar används en linjär modell för att göra problemet mer lätthanterligt. Insignalerna till systemet är kraften från stjärtrotorn och lutningsvinklarna av huvudrotorns Tip-Path-Plane. En kaskadregulator används för att styra translationssystemet med eulervinklarna och kraften från huvudrotorn, som insignaler. Regulatorn testas i en MATLAB-simulering mot en glatt referensbana med godkända resultat. För landingsproceduren används en banplaneringsstrategi som bygger på linjär prediktiv reglering (PR). Kaskadregulatorn används sedan för att följa translationsreferenserna, vilka blir valda så att även attitydsystemet anpassas efter plattformens attityd i landningsögonblicket.

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Leitner, Jesse. "Helicopter nonlinear control using adaptive feedback linearization". Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/11985.

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48

Line, Andrew James. "Computational modelling of helicopter high-frequency dynamics". Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413420.

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Wallace, Malcolm William George. "Improvements to Helicopter Indirect Structural Health Management". Thesis, University of Southampton, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.503148.

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Joy, Christopher Iain Harold. "GPS assisted helicopter photogrammetry for highway profiling". Thesis, University of Nottingham, 1998. http://eprints.nottingham.ac.uk/11462/.

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Roads are an integral part of today's lifestyle. Indeed, a modern and efficient economy requires a satisfactory road network. The road network in the United Kingdom faces ever-increasing demands with 94% of passenger travel and 92% of freight transport undertaken by road. Maintenance of the network is essential. Prior to the commencement of any maintenance scheme, an accurate highway profile is measured by undertaking a detailed topographic survey of the road surface and the adjacent verges. Traditionally, this is carried out by land surveyors using, for example, a theodolite, EDM and level. Highway surveying by traditional methods is a slow, costly and dangerous process. A photogrammetric technique was devised by Photarc Surveys Ltd of Harrogate, UK to reduce the problems of speed, cost and safety. This helicopter based photographic system can yield topographic data at up to ±5mm rmse through photogrammetric analysis. It is necessary to install ground control points on the hard shoulder for use in the photogrammetric analysis. This research investigates the potential of both conventional aerial triangulation and in-flight GPS assisted aerial triangulation for reducing this ground control requirement. The original photographic system is extended to integrate a GPS positioning system and the performance of this system is assessed through a series of field trials. The results of the research show that the camera can be positioned by the GPS system to within 5 centimetres. The GPS positions can be included in the aerial triangulation to further reduce the requirement for ground control. It is shown that for mapping at the ± 5mm rmse level, there is no potential for height control reduction, even when GPS positions are used. However for mapping at up to ± 20mm, the GPS positions can enable a significant reduction in ground control.

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