Авіаційно-космічна техніка та технологія (Dec 2018)
METHODS AND INSTRUMENTS FOR NONCONTACT DIAGNOSTICS OF THE TCAS SYSTEM
Abstract
This article is devoted to an investigation of the TCAS (Traffic Collision Avoidance System) diagnostics and self-diagnostics problems. The aim of the current research is to prepare the TCAS system built-in diagnostics aid and to build a model of a device for non-contact monitoring of the TCAS unit operational status. The tasks of the research are the following: to conduct analysis of the features and capabilities of the TCAS diagnostic techniques and aids; to develop a model which can detect the spurious actuation of the system and false decision-making; to prepare techniques which can detect such behavior of the system during a flight; to construct a model of a device for built-in diagnostics based on an non-contact monitoring of the TCAS states. The applied techniques of the researches are the following: application of signs, facts, and heuristic information about faults, implementation of an instrumental approach and diagnostic techniques based on an estimation of measured and monitored parameters. The system state monitoring method was proposed to carry out non-contact diagnostics of the system and to monitor the operating modes. This method is based on operating current variations by means of current measure using non-contact meters. It was proposed to apply the Hall sensor and the Rogowski coil to carry out such diagnostics. The schematic model to monitor the operation of the TCAS receiving and computing unit is developed considering Hall sensors’ capabilities to measure both direct and alternating currents. It was proposed the method and schematics to monitor TCAS system transmitter operating modes due to the fact that Rogowski coil is capable to measure both pulse and HF currents. This promotes to carry out diagnostics of the system proper operation. Several model versions of Rogowski coil are developed. Researches were carried out applying self-contained testing device (АКИП – 3407/2А) and Tektronics TSB digital oscilloscope. Conclusions. The novelty of the carried researches is follows: it is proposed a method for monitoring the variations of operating currents applied by the TCAS basic units for providing the self-contained diagnostics system; it is proposed a method for monitoring the system state according to the operating current variations, based on current measurements applying the Hall sensor and the Rogowski coil to provide the TCAS non-contact diagnostics. The research includes analysis of the laboratory measurements which were performed applying several versions of the Rogowski coil. Functional diagrams of the coil connections to the circuit are developed applying MultiSim14. The logical unit of the TCAS electrical modes built-in monitoring device is developed applying MatLab and MultiSim14
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