Precision active power measuring channel

The article is devoted to increasing the reliability, noise protection and improving the metrological characteristics of active power measuring converters. Much attention is paid to the problem of developing effective methods for constructing structural diagrams of active power measuring converters. This is explained by the growing requirements for the basic metrological characteristics of active power measuring converters as elements of information – measuring systems. The main attention in the work is paid to the development of ways to correct the influence of destabilizing factors in working conditions. The undoubted advantage of the work is a thorough analysis of the instrumental errors of the measuring channel, the original means of correction of the phase error and the error due to the limited suppression coefficients of in-phase interference. The obtained simulation results in the Electronics Workbench environment made it possible to determine the most effective way to protect against interference.

Information Conversion in Measuring Channels with Optoelectronic Sensors

The purpose of this work is the authors’ attempt to identify the main phases of information transformation in measurement channels on the example of an optical measurement channel with microprocessor control. The authors include such phases: hardware implementation and analytical representation of an optical sensor`s converting functions and a current-to-voltage converter; based on the methods of experimental computer science, the converting functions and sensitivity are deduced, analytical dependences for estimation of a range of measurement are obtained. It is shown that the choice of information transmission type in the microprocessor measuring channel significantly affects the speed of the measuring channel. Based on the uncertainty in the form of entropy before and after measurements, the amount of information for measuring channels with optoelectronic sensors is estimated. The application of the results obtained in the work allows even at the design stage of physical and mathematical modeling to assess the basic static metrological characteristics of measuring channels, aimed at reducing the stage of development and debugging of hardware and software and standardization of their metrological characteristics.

Intrinsic background of the beta channel of the aerosol volumetric activity monitor

The work is devoted to the study of the features of generation of the intrinsic background of the measuring beta channel of the aerosol monitor in real conditions of measuring the volumetric activity of aerosols, caused by radionuclides of technogenic origin. The influence of external factors on the generation of the level of the intrinsic background of the measuring channel of the monitor and its metrological characteristics is investigated. The reliability of the results of measurements of the volumetric activity of air aerosols substantially depends on the correct accounting of external factors, parameters of the monitored environment and the specified operating mode of the monitor. Aerosol volumetric activity monitors, as a rule, operate in a continuous mode, in which the aspiration method of aerosol accumulation is implemented, followed by measuring the volumetric activity of aerosols by alpha radiation and (or) beta radiation generated by technogenic radionuclides. This article describes the results of experiments on measuring the iCAM aerosol monitor’s intrinsic beta channel background under real operating conditions, and its dependence on external factors. The studies were carried out on iCAM aerosol monitors (iCAM/D and iCAM/MF modifications) manufactured by Canberra Industries Inc. in a laboratory room in normal climatic conditions with a radon volumetric activity of 35±10 Bq·m-3 and an equivalent dose rate of gamma radiation of 0.13±0.02 μSv·h-1. In modern aerosol monitors, software and hardware solutions are implemented that allow to significantly reduce the background level and, as a result, to expand the measurement range of the volumetric activity of aerosols towards low values.

LAND UNMANNED COMPLEX WITH PASSIVE RANGE MEASUREMENT

The automatic robotic complex will obviously become one of the main subjects in the conduct of military actions in the near future. To control movement parameters, as well as search, target detection and aiming, the complex includes a technical vision system. The minimum sufficient configuration of such a system includes a television search camera with a wide field of view, television and thermal imaging sights, and a rangefinder. The use of laser rangefinders ensures high accuracy of aiming weapons, but generates a powerful unmasking feature. To ensure the secrecy of the functioning of the robotic complex, range finders can operate in a passive mode using information from on-board television cameras. But at the same time, the metrological characteristics of the information measuring channel are significantly deteriorated. Accuracy of five methods of passive distance measurement with application of TV-systems of land unmanned complex is assessed in paper. Classic method of TV-sight external-base range-finder with scale, designed on human height 1,65 m, is ensuring measurement accuracy 135 m on distance 1000 m. External base method, when a range finger scale is forming on remote display as variable length vertical line in process of target framing, is ensuring measurement accuracy 100,3 m on dis-tance 1000 m. Fixed-base range-finder method, when distance between entrance pupils of TV-sight and wide viewing field camera using as base, is ensuring measurement accuracy 76 m on distance 1000 m. Distance measurement method due to displacement of land unmanned complex ensures a measurement accuracy up to 168 m on distance 1000 m. Measurement method due to using zoom-objective is not suitable for land unmanned complex. Proposals have been formulated for the spatial layout of the computer vision system, in which the method of the fixed-base rangefinder is implemented, which ensures the highest measurement accuracy.

Analysis of the Downhole Measurement System’s Pressure and Temperature Measuring Channel Calibration Errors

Various measurements in wells are quite challenging due to the specific measurement conditions. There are some additional requirements for measurement systems, in particular, space restrictions. Therefore, measuring several parameters with a single sensor is rather important. The paper discusses a measurement system that allows measuring temperature and pressure with a single sensor – an SOS-based strain gauge pressure transducer with a bridge or half-bridge circuit. In this case, pressure and temperature measuring channels are calibrated individually, which creates another error component. The numerical simulation of calibration described herein shows that regardless of the sensor circuit, the voltage uncertainty band of both measuring channels is characterized by a reduced error of 0.03 % with a confidence probability P = 0.9.

Optical Theodolite Based Rationality Check of Measurement Data From Pulse Radar

Theodolite and radar are important measurement and control devices in aviation, aerospace and other fields. In order to make sure the tracking measurement and navigation control of aircraft and spacecraft safely, this paper creatively proposes a novel method to check the rationality of the three-dimensional measurement data (distance, azimuth and pitch angle) of the pulse radar by using the two-dimensional measurement data (azimuth and pitch angle) of the optical theodolite. Specifically, three different rationality checking functions are constructed for the three different cases of unreliable ranging channel, unreliable angle measuring channel and unreliable ranging and angle measuring channels, and are used for the rationality checking of radar data in the above three cases respectively. Simulation results show that the correct rate is more than 95% as long as the data measured by optical theodolite are reliable.

Измерение напряженно-деформированного состояния деталей АГТД методом тензометрии

The subject of study in the article is various methods of measuring the stress-strain state of AGTE parts by the tensometry method. Differences were revealed when measuring the stress-strain state of rotor and stator parts, in different frequency ranges (study of static, static-dynamic and dynamic deformations). Methods for compensating or reducing the influence of external factors on the measurement results, such as temperature changes and electromagnetic interference, are indicated. The aim is to develop recommendations for research of AGTE parts in a test bench in a gradient of varying temperatures and in a complex electromagnetic environment of the engine. A review of the sources of inaccuracies, errors and interference arising during preparation for testing and directly during the measurement of the SDS of AGTE parts is performed. The effects of wiring, cabling, grounding and shielding can not only increase the level of errors, but can also negate the advantages of an expensive and extremely reliable electronic part of the system. The advantages and disadvantages of the most common schemes for connecting strain gages, as well as their areas of application are presented. Possible ways to compensate for imaginary deformations at temperatures outside the range of thermal compensation of primary converters. A list of common strain gauge systems with their advantages and disadvantages is given for each type of parts and frequency ranges of measurements. When strain measurement rotary parts to output the signal from the strain gauge to recording equipment used various current collector. The possibility of using wireless interfaces for communication between the primary converter and the recording equipment is also indicated. The described methods are: ways to compensate for imaginary deformations caused by changes in the temperature of the investigated part and connecting wires. Elimination or minimization of electromagnetic interference on the measuring channel. An estimate is given of the total error in measuring the deformation for a particular object under study for the final loading cycle, the specificity of the bench strain gauge path, the errors of the current collector in bench conditions, and others in the process of static strain gauging.

Assessment of Health Monitoring Trustworthiness of Avionics Systems

The article provides a methodology for assessing the trustworthiness of health monitoring the dismounted avionics systems with automated test equipment (ATE). The indicators include the probabilities of false-positive, false-negative, true-positive, and true-negative. For the first time, we introduced into consideration the instability of the source of stimulus signal (SSS), the random and systematic component of the measuring channel error, and the reliability characteristics of the systems themselves. We consider a specific case of an exponential distribution of permanent failures and intermittent faults and derive formulas for calculating the trustworthiness indicators. Numerical calculations illustrate how the probabilities of correct and incorrect decisions depend on accuracy parameters. We show that the probabilities of false-positive and false-negative increase much faster than the probabilities of true-positive and true-negative decrease when the standard deviation of stimulus signal increases. For a Very High-Frequency Omni-Directional Range (VOR) receiver, we demonstrate that even with a zero random error generated by the source of the stimulus signal, the probabilities of false-positive and false-negative are different from zero.