• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 14
  • 2
  • Tagged with
  • 17
  • 17
  • 5
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
1

The Design of Dynamic Calibration Procedure

Leite, Nelson Paiva Oliveira, Sousa, Lucas Benedito dos Reis 10 1900 (has links)
ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / The execution of experimental Flight Test Campaign (FTC) provides all information required for the aircraft operation and certification. Nowadays all information gathered during a FTC is provided by the Flight Test Instrumentation System (FTI) that is basically a measurement system. Typically for all FTI parameters, the estimation of the calibration coefficients that minimizes most of systematic errors and its associated uncertainty is carried out by a Static Calibration Process. To execute this task the Brazilian Institute of Research and Flight Test (Instituto de Pesquisa e Ensaios em Voo - IPEV) developed the Sistema de Automação do Laboratório de Ensaios em Voo (SALEV©) which is fully compliant with the calibration and uncertainty expression standards. For some parameters (i.e. Static Pressure) the sensor installation particularities (i.e. Pressure tapping) introduces low pass filtering characteristics into the measurement chain. In this case the measurement accuracy will be jeopardized when executing high-dynamic test points (i.e. Spin Tests). To overcome this issue the IPEV research and development group introduced a dynamic calibration process for flight test parameters that requires the knowledge of the actual Transfer Function (TF). The problem now is to simulate an impulsive input for the TF characterization which is too complex. To solve this issue a new calibration procedure was developed and evaluated for the determination of the FTI dynamic response. SALEV© was used to simulate a step input instead of an impulse. Then filtered and unfiltered data was properly compared for the determination of the TF. Preliminary test results show satisfactory performance.
2

iPCM Telemetry System

Leite, Nelson Paiva Oliveira, Carvalho, Marco Aurélio 10 1900 (has links)
ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / The execution of experimental Flight Test Campaign (FTC) provides all information required for the aircraft development, operation and certification. Typically the execution of a FTC encompasses three major systems as follows: Flight Test Instrumentation System (FTI) that is basically a measurement system; Real-Time Telemetry Link (RTL); and Ground Telemetry System (GTS). At the early days, for the development of small aircrafts (i.e. Fighter), the primary source for FTI data was provided by the RTL due to inherent limitations of the open reel airborne data recorders (i.e. media and size), operating under high-dynamics condition. Nowadays with the introduction of solid-state data recording devices, data integrity and reliability is no longer an issue. At the ITC 2010 Blue Ribbon Panel, Mr. Thomas Beard, the executive Director of the Air Force Flight Test Center in Edwards Air Force Base emphasized the need to reduce refly and to improve FTC efficiency. Such statement imposes a new paradigm in Telemetry, which is to improve RTL integrity and reliability level equivalent to the solid-state data recording devices. Therefore the Telemetry community will be able to execute test point validation for refly reduction and quasi realtime data reduction analysis for efficiency improvement. The major solutions that address such issue are Spatial Diversity (SD) architectures and the iNet. The SD solution requires multiple antenna system (which is very expensive) that could still produce ineffective results at high-dynamics test points (e.g. Spin). At the beginning the iNet consortium proposed the usage of TCP protocol for data transmission. Problems associated with TCP limitations such as data latency and overhead lead to the usage of UDP protocol that does not guarantee the packet delivery. To properly address these issues the IPEV R&D group proposes the iPCM Telemetry architecture to be used as RTL. The iPCM uses hybrid architecture for data transmission taking the advantage of legacy digital transmitters combined with iNet-based transceivers to retrieve missing data. The development and the evaluation of iPCM architecture will be executed as a PhD Thesis in ITA University. The expected performance and benefits of iPCM are presented and discussed.
3

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).
4

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.
5

Uncertainty Determination with Monte-Carlo Based Algorithm

Leite, Nelson Paiva Oliveira, Sousa, Lucas Benedito dos Reis 10 1900 (has links)
ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / The measurement result is complete only if it contains the measurand and its units, uncertainty and coverage factor. The uncertainty estimation for the parameters acquired by the FTI is a known process. To execute this task the Institute of Research and Flight Test (IPEV) developed the SALEV© system which is fully compliant with the applicable standards. But the measurement set also includes Derived Parameters. The uncertainty evaluation of these parameters can be solved by cumbersome partial derivates. The search for a simpler solution leads us to a Monte-Carlo based algorithm. The result of using this approach are presented and discussed.
6

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.
7

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.
8

Tracking Track Targets in External Store Separation Using Computer Vision

Kusomoto, André Yoshimi, de Vasconcelos, Luis Edwardo Guarino, Leite, Nelson Paiva Oliveira, Lopes, Cristina Monis Araújo, Pirk, Rogério 10 1900 (has links)
ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CA / Flight tests and flight safety are tightly coupled. For a given experimental test flight, the main objective to be achieved is related to the test bed and crew integrity (i.e. Bring back the test bed in one piece). Furthermore, the aircraft operational safety (i.e. continued airworthiness) relies into the accuracy of gathered information, provided by the airborne Flight Test Instrumentation (FTI) system. Typically, the FTI system includes: a data acquisition system; a transmission system; a data recorder; multiple sensors and auxiliary equipment such as Global Navigation Satellite System (GNSS) Receiver. In a specific Flight Test Campaign (FTC), such as external stores separation FTC, the associated risk is high because the non-linear and unpredicted aerodynamics couplings between the released store and the aircraft structure (e.g. wings) could lead to a catastrophic collision condition. Typically, the setup for such FTC is a big technical challenge for the instrumentation group because the determination of six degrees of freedom (6Dof) trajectory of the release store becomes mandatory. Such information could be by the means of an optical tracking system that requires the integration of two or more hi-speed hi-resolution video cameras into FTI. Unfortunately, the FTI and the Real-Time Telemetry Link (RTL) limited bandwidth imposes several restrictions for the development and implementation of a real-time application to be used at the Ground Telemetry System (GTS) for the verification of the separation safety and the validation of the test point. This paper, presents the implementation of computer vision techniques and Camshift algorithm as an approach to tracking individual track targets on the store surface which can be perform onboard and in real time or near real time. The development of the algorithm is presented as well several experimental test results that use videos frames gathered from previous FTC executed by Instituto de Pesquisas e Ensaios em Voo (Flight Test and Research Institute - IPEV). Preliminary results present satisfactory performance.
9

MULTIPLE TIME BASE SYCHRONIZATION PROCESS APPLIED TO THE FLIGHT TESTS CAMPAIGN OF A GPS ATTITUDE DETERMINATION ALGORITM

Leite, Nelson Paiva Oliveira, Walter, Fernando 10 1900 (has links)
ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / For the final evaluation of a GPS attitude determination algorithm, it was determined its true performance in terms of its 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 THALES Z-FX airborne GPS receivers and a complete Flight Tests Instrumentation (FTI) System. Each GPS receiver operates synchronized with its internal time base. The FTI measurements are synchronized to an IRIG-B time base. All time bases have their own random walk characteristic. To avoid C/A code ambiguity, when its internal time base approaches ±1ms error from the GPS time, its clock is then corrected causing time and phase observables discontinuities. A multiple time base synchronization process was developed to correlate GPS and FTI data. The results are presented and the residual errors were considered acceptable. These data allowed the determination of the performance and accuracy of the GPS attitude determination algorithm. The tests profiles are fully compliant with the Federal Aviation Administration (FAA) Advisory Circular (AC) 25-7A.
10

The Design of an Application Used for Aircraft Stability Evaluation

Leite, Nelson Paiva Oliveira, Lopes, Leonardo Mauricio de Faria, Walter, Fernando 10 1900 (has links)
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 / One of the most important characteristics of an aircraft is its capability to return to its stable trimmed flight state after the occurrence of a disturbance or gust without the pilot intervention. The evaluation of such behavior, known as the aircraft stability, is divided into three sections: Lateral; Directional; and Longitudinal stabilities. The determination of the stability of an experimental aircraft requires the execution of a Flight Test Campaign (FTC). For the stability FTC the test bed should be equipped with a complete Flight Test Instrumentation (FTI) System which is typically composed by: a Pulse Code Modulation (PCM) Data Acquisition System (DAS); A sensor set; An airborne transmitter; and A data recorder. In the real-time operations, live data received over the Telemetry Link, that are processed, distributed and displayed at the Ground Telemetry System (GTS) enhances the FTC safety level and efficiency. The due to the lack of reliability, recorded data is retrieved in the post mission operations to allow the execution of data reduction analysis. This process is time consuming because recorded data has to be downloaded, converted to Engineering Units (EU), sliced, filtered and processed. The reason for the usage of this less efficient process relies in the fact that the real-time Telemetry data is less reliable as compared to recorded data (i.e. noisier). The upcoming iNET technology could provide a very reliable Telemetry Link. Therefore the data reduction analysis can be executed with live telemetry data in quasi-real time after the receipt of all valid tests points. In this sense the Brazilian Flight Test Group (GEEV) along with EMBRAER and with the support of Financiadora de Estudos e Projetos (FINEP) started the development of several applications. This paper presents the design of a tool used in the Longitudinal Static Stability Flight Tests Campaign. The application receives the Telemetry data over either a TCP/IP or a SCRAMnet Network, performs data analysis and test point validation in real time and when all points are gathered it performs the data reduction analysis and automatically creates Hyper Terminal Markup Language (HTML) formatted tests reports. The tool evaluation was executed with the instruction flights for the 2009 Brazilian Flight Test School (CEV). The result shows an efficiency gain for the overall FTC.

Page generated in 0.2075 seconds