• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 881
  • 292
  • 102
  • 75
  • 69
  • 44
  • 25
  • 12
  • 11
  • 10
  • 9
  • 7
  • 7
  • 7
  • 7
  • Tagged with
  • 1956
  • 409
  • 373
  • 300
  • 244
  • 226
  • 183
  • 154
  • 143
  • 134
  • 126
  • 125
  • 120
  • 115
  • 115
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
201

HIGH ALTITUDE TRANSMITTER FLIGHT TESTING

Brown, K. D., Sorensen, Trevor 10 1900 (has links)
International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / This paper describes a high altitude experimental flight test platform developed by the University of Kansas (KU) and the National Nuclear Security Administration’s Kansas City Plant (NNSA’s Kansas City Plant) for high altitude payload flight testing. This platform is called the Kansas University Balloon Experiment Satellite (KUBESat). The paper describes the flight test platform and experimental flight test results captured at Fort Riley, KS from characterization of the KCP developed Distributed Transmitter (DTX).
202

A comparison of whole life cycle costs of robotic, semi-automated, and manual build airport baggage handling systems

Bradley, Alexandre January 2013 (has links)
This thesis proposes that a baggage handling system (BHS) environment can be defined and coupled to a whole life cycle cost (WLCC NPV) model. The results from specific experiments using the model can be used as the basis by which to commercially compare BHS flight build types of any capacity, and BHS geographical location. The model examined the three flight build types(i): Fully automatic build2; (ii) Semi-automatic build, and(iii); Manual build. The model has the ability to calculate a bag flow busy hour rate, and to replicate the baggage flow characteristics observed within real BHS operations. Whole life cycle costs (WLCC NPV) results are produced, and these form the basis by which the comparison of BHS types is made. An overall WLCC NPV scatter diagram was produced, which is a summation of each of the test sensitivities. The assumptions and limitations of the analysis are provided. It is proposed that the results, conclusions and recommendations shall be of value to airports, airlines, and design consultants.
203

Dynamic Wake Distortion Model for Helicopter Maneuvering Flight

Zhao, Jinggen 10 April 2005 (has links)
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.
204

A comparison of whole life cycle costs of robotic, semi-automated, and manual build airport baggage handling systems

Bradley, Alexandre 05 1900 (has links)
This thesis proposes that a baggage handling system (BHS) environment can be defined and coupled to a whole life cycle cost (WLCC NPV) model. The results from specific experiments using the model can be used as the basis by which to commercially compare BHS flight build types of any capacity, and BHS geographical location. The model examined the three flight build types(i): Fully automatic build2; (ii) Semi-automatic build, and(iii); Manual build. The model has the ability to calculate a bag flow busy hour rate, and to replicate the baggage flow characteristics observed within real BHS operations. Whole life cycle costs (WLCC NPV) results are produced, and these form the basis by which the comparison of BHS types is made. An overall WLCC NPV scatter diagram was produced, which is a summation of each of the test sensitivities. The assumptions and limitations of the analysis are provided. It is proposed that the results, conclusions and recommendations shall be of value to airports, airlines, and design consultants.
205

Modeling, simulation, hardware development, and testing of a lab-scale airborne wind energy system

Klein-Miloslavich, Andreas 24 January 2020 (has links)
Airborne Wind Energy Systems (AWES) harness the power of high-altitude winds using tethered planes or kites. Continuous and reliable operation requires that AWES become autonomous devices, but the wind intermittency forces the system to repeatedly take-off to start, and land to shut-off. Therefore, a common approach to facilitate the operation is implementing Vertical take-off and landing (VTOL) functionality. This thesis models and simulates AWES flights working towards the implementation of flight controller hardware and autonomous operation of an AWES demonstrator platform. The Ardupilot open-source autopilot platform provides a convenient tool for modeling, simulation, and hardware implementation of small-scale airplanes. An AWES lab-scale demonstrator was developed to obtain operational insight, get preliminary flight data, and real-world experience in this technology. A quadplane was developed by combining a structurally reinforced glider with VTOL and autopilot components. Its performance is obtained from static and aerodynamic studies and converted into the Ardupilot parameter format to define it in the simulation. An AWES flight model was developed from the ground up to evaluate the performance of a simple flight controller in trajectory tracking. The Ardupilot Software-in-Loop (SIL) tool expands the simulation capabilities by running the flight controller code without requiring any hardware. This allowed controller tuning and flight plan evaluation with a more advanced fight model. AWES crosswind flight simulation was only possible due to the incorporation of an elastic tether and an ideal winch into the physics model. As a result, different trajectories and configurations were tested to find the optimal parameters that were uploaded to the flight controller board. The operational capabilities of the AWES demonstrator were expanded with a flight testing campaign. By targeting individual objectives, each test gradually increased its complexity and ensured that the flight envelope was safely expanded. The results were validated with the simulation before moving on to the next flight test. The testing campaign is still underway due to challenges and limitations presented by the legal and logistical aspects of operating the quadplane. However, preliminary flight tests in VTOL mode have been completed and were consistent with the simulated results in terms of autonomous waypoint navigation and attitude control. / Graduate
206

ECONOMIC IMPACT OF TELEMETRY AND ITS ESSENTIAL ROLE IN THE AEROSPACE INDUSTRY

Kahn, Carolyn A. 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper shows the economic implications associated with the allocation of spectrum for aeronautical telemetry. It explores both the economic implications of aeronautical telemetry spectrum and its flight testing application. The overall importance of telemetry to the economy, including applications of telemetry beyond flight testing, is also examined. An understanding of the economic implications of telemetry is crucial to the consideration of World Radio Conference (WRC) 2007 Agenda Item 2.12 that is proposing the allocation of additional spectrum for wideband aeronautical telemetry in the 3-30 gigahertz (GHz) band.
207

A MULTIFUNCTION SATELLITE BACKHAUL SYSTEM FOR AIRCRAFT FLIGHT TEST APPLICATIONS

Bell, John J. (Jack), Mileshko, James, Payne, Edward L., Wagler, Paul 10 1900 (has links)
International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / This paper will present the design of a network used to receive and record sensor data and provide voice communications between a flight controller and the pilot of an aircraft undergoing flight testing in remote areas. The network utilizes a completely self-contained mobile tracking subsystem to receive and relay the sensor data and cockpit voice in real-time over a geostationary satellite. In addition to the aircraft tracking and data/voice relay functions, the system also provides local data recording at the mobile station, telephone and intercom connectivity between the mobile station and the control center, and remote equipment setup via the satellite link.
208

AUTOMATION SYSTEM FOR THE FLIGHT TEST LABORATORY (SALEV)

Sousa, Lucas Benedito dos Reis, Leite, Nelson Paiva Oliveira, Walter, Fernando, Cunha, Wagner Chiepa 10 1900 (has links)
ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / A novel Automation System for the Flight Test Laboratory (SALEV) is developed in full compliance with EA-4/02 Standard (i.e. Expression of the Uncertainty of Measurement in Calibration) to compute the uncertainty of the measurement at the calibration laboratory of the Flight Tests Group (GEEV). The GEEV performs flight test campaigns to certificate and/or develop aircrafts and its systems. Then, flight tests instrumentation (FTI) systems are developed and installed in the test bed. The FTI data acquisition complies with IRIG Standard. The FTI is composed by a data acquisition system, which performs signal conditioning, sampling and quantization of all measurements provided by a set of transducers. All parameters are coded in a PCM format and represented in a non-dimensional numerical form (i.e. counts).To allow the establishment of a relation between the non-dimensional form and the physical quantity, a calibration process is carried out to provide the coefficients of a calibration curve. This process is also used to determine the systematic and random errors (i.e. the uncertainty). The accuracy and reliability of calibration process should comply with the requirements, which are customized for each flight test campaign. The satisfactory performance of the SALEV calibration process is achieved by automation in all steps. The SALEV development is presented, which includes the following steps: · Database definition; · Study of all steps and parts that forms the calibration process (i.e. from transducer to final uncertainty determination) to determine its associated uncertainties; · Automation of the entire calibration process (including the process itself up to the effective control of standard and instruments); · Development of algorithms to compute the uncertainty compliant with EA 4/02; and · System validation in compliance with ISO/IEC 17025. As result of the SALEV operation, it could be verified that measurement quality was improved, and the required time for calibration was substantially reduced. Also the standardization of this process allows failures forecast due to aging of systems parameters (i.e. bias).
209

STATIC AND DYNAMIC EVALUATION OF A GPS ATTITUDE DETERMINATION SYSTEM BASED ON NON-DEDICATED GPS RECEIVERS

Leite, Nelson Paiva Oliveira, Walter, Fernando 10 1900 (has links)
ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / For the final evaluation of a GPS attitude determination algorithm, it was determined its true performance in terms of accuracy, reliability and dynamic response. To accomplish that, a flight test campaign was carried out to validate the attitude determination algorithm. In this phase, the measured aircraft attitude was compared to a reference attitude, to allow the determination of the errors. The system was built using non-dedicated airborne GPS receivers, and a complete Flight Tests Instrumentation (FTI) System. The flight test campaign was carried out at the Brazilian’s Flight Test Group T-25C 1956 Basic Trainer aircraft. The performance and accuracy of the system is demonstrated under static and dynamics tests profiles, which are fully compliant with the Federal Aviation Administration (FAA) Advisory Circular (AC) 25-7A. Dynamic response of the system is evaluated.
210

FLIGHT TESTS OPTIMIZATION BY SATCOM BASED TELEMETRY LINK

Rodrigues, Tiago Giglio, Góes, Luis Carlos Sandoval, Leite, Nelson Paiva Oliveira, Marins, Carlos Nazareth Motta 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / The terrestrial microwave telemetry links show limitation due their inherent features concerning bandwidth availability, frequency allocation and range. Also it supports only one aircraft per test and the data acquisition capacity can be enhanced. Following the flight tests trends, it proposes a telemetry link based on satellite communications deployed by off the shelf equipments allowing advantages as bandwidth availability, multiple aircrafts telemetry and almost global range into the reliability standards. By simple equations and typical flight tests data it demonstrates the feasibility of the telemetry system proposed for time and costs reduction to optimize flight tests programs.

Page generated in 0.0369 seconds