• AUTOMATION SYSTEM FOR THE FLIGHT TEST LABORATORY (SALEV)

      Sousa, Lucas Benedito dos Reis; Leite, Nelson Paiva Oliveira; Walter, Fernando; Cunha, Wagner Chiepa; CTA - Grupo Especial de Ensaios em Vôo; ITA - Divisão de Eletrônica (International Foundation for Telemetering, 2006-10)
      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).
    • STATIC AND DYNAMIC EVALUATION OF A GPS ATTITUDE DETERMINATION SYSTEM BASED ON NON-DEDICATED GPS RECEIVERS

      Leite, Nelson Paiva Oliveira; Walter, Fernando; CTA - Grupo Especial de Ensaios em Vôo; ITA - Divisão de Telecomunicações (International Foundation for Telemetering, 2006-10)
      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.