Analysis of Ensuring Stability of Metrological Characteristics of Velocity Head Meter in Flight Conditions of Aircraft in Upper Atmosphere
When measuring small, slowly changing physical parameters, such as parameters of the velocity of low-density gas flows, small values of aerodynamic forces, aerodynamic forces acting on aircraft in conditions of a rarefied gas environment, electrical signals coming from primary converters often have a low level, sometimes reaching very small values, is much less than the level of noise and interference. The most acceptable way of measuring such physical quantities in obtaining reliable results is the electromechanical modulation (interruption) of the oncoming gas flow by means of flow interrupters, which allows obtaining the required higher amplification of the signal of the modulated signal, it is easy to separate the modulated signal from the unmodulated noise and interference signal, even if the level of the useful signal is lower than the level of noise and interference. Successful in solving such a problem is the use of signal accumulation, which increases the signal-to-noise ratio at the converter output. The paper presents the results of an investigation of a high-speed pressure transducer for a gas medium of low density. The stability of the metrological characteristics of the converter is investigated using the method of probabilistic study of the stability of the output characteristic of a membrane-capacitive converter to determine the optimum frequency of electromechanical transformation and to ensure the specified accuracy and stability of its metrological characteristics, taking into account the random nature of the deviation of structural and electrophysical parameters associated with destabilizing factors and technological factors.