Vladimir D. Kuptsov

A techniques to measurement noise figure of microwave fiber optic transmission line is given. Two method of noise figure measurement - the Y-factor method and the direct noise figure measurement method - are discussed and compared. The structure of lab setup of microwave fiber optic line and characteristics of its component, and characteristics of used measurement equipment are given. We measure output noise power spectral density, power gain and noise figure. Lab setup line has noise figure 28.5… 32.5 dB in studied frequency range.

A technology for estimating the chromatic dispersion parameter of a single-mode fiber is presented. The technique is based on high-precision measurement of the phase-frequency dependence in transfer characteristics of a microwave photonic link. Link transfer characteristic measurements are realized at two known optical carriers by a vector network analyzer and then the difference in phase-frequency dependences is used for fiber dispersion calculation. The results of experimental studies and the calculation of the error in estimating the dispersion parameter are presented.

The manuscript presents an algorithm for the optimal estimation of the amplitude and propagation delay time of an ultra-wideband radio signal, in systems for the passive location of fixed targets based on the hybrid RSS/TDoA method in two-dimensional space with two base stations. The optimal estimate is based on the Bayesian strategy of maximum a posteriori probability density, taking into account a priori data on the statistical properties of the Line of Sight radio channel during Gaussian monocycle propagation. The Bayesian Cramer–Rao lower bound (BCRLB) of the delay time and the amplitude estimates for a time-discrete signal are calculated, and the resulting parameter estimate is compared with BCRLB. An algorithm has been developed for optimal estimation of distances from the radiation source to base stations, based on the results of the measurements of the amplitude and the propagation delay time of the UWB radio signal. The calculation of the statistical characteristics of the obtained estimate is carried out, and the functional dependence of the characteristics on various parameters is analyzed.

The necessity of using spectral analysis to study the structure of the line of the nuclear magnetic resonance (NMR) signal recorded using the modulation technique has been substantiated. The specifics of its use in researching condensed media in both current and stationary states have been determined. It was found that it is necessary to use the discrete Fourier transform to construct the amplitude and phase spectra from the experimental NMR signal recorded from the medium under study, as well as from the absorption and dispersion signals calculated for this medium using the Bloch equations with new coefficients. A technique has been developed for comparing spectra from experimental and calculated NMR signals to determine the line structure. The research results are presented.

The paper presents the results of theoretical simulation of mmWave, cmWave and visible light attenuation in rain based on the Mie scattering theory. Specific rain attenuation has been estimated from the gamma drop size distribution for a spherical drop. Rain attenuation of electromagnetic waves in the visible range, used by video cameras and lidars of «smart» city vehicles, and at the beginning of the millimeter wave range used by radars and positioning systems, have similar values averaging 3-5 dB/km. The attenuation levels of electromagnetic waves in mmWave, cmWave and Visible light ranges must be taken into account when calculating the energy budget of vehicle communications.

A rigorous mathematical description of the signal reflected from a moving object for radar monitoring tasks using linear frequency modulated continuous wave (LFMCW) microwave radars is proposed. The mathematical model is based on the quasi-relativistic vector transformation of coordinates and Lorentz time. The spatio-temporal structure of the echo signal was obtained taking into account the transverse component of the radar target speed, which made it possible to expand the boundaries of the range of measuring the range and speed of vehicles using LFMCW radars. An algorithm for the simultaneous estimation of the range, radial and transverse components of the velocity vector of an object from the observation data of the time series during one frame of the probing signal is proposed. For an automobile 77 GHz microwave LFMCW radar, a computer experiment was carried out to measure the range and velocity vector of a radar target using the developed mathematical model of the echo signal and an algorithm for estimating the motion parameters. The boundaries of the range for measuring the range and speed of the target are determined. The results of the performed computer experiment are in good agreement with the results of theoretical analysis.

Accurate remote determination of the object coordinates in 3D space is one of the main questions in many applications. In one of the most popular methods, such determination of the location of an object uses the measurement by receiving an electromagnetic signal transmitted by several spatially distributed base stations (BS). The main problem is that it is necessary to reduce errors and computation time. To overcome these difficulties, an analytical method for determining the position of an object based on the analysis of time difference of arrival (TDoA) of signals from the transmitter of the object to the receivers of the BS is proposed. One of the main advantages of this method is that it is possible to eliminate the ambiguity in determining the coordinates of the object in space and to increase the accuracy of determining the coordinates when the TDoA measurement between base stations fluctuates. Applications for autonomous automotive vehicles and space-based positioning systems are analyzed. The results obtained show that the proposed algorithm has an accuracy of determining coordinates several times higher than the method of linearization of hyperbolic equations and is less sensitive to TDoA fluctuations at base stations.

The results of synthesis and analysis of the effectiveness of the optimal location-based system for joint detection and estimation of informative parameters of quasi-determined radar signals with frequency modulated continuous wave are presented. A method has been developed for calculating the noise immunity indices of frequency modulated continuous wave radars and the detection threshold of signals in the quadrature channels of the optimal radar receiver based on off-center χ‘²-distribution for given technical characteristics of the location system, including the mode of operation for detecting and evaluating parameters in multi-target mode.

This article explores the properties of the multi-target method for small unmanned vehicles parameters remote determination by microwave radars, which allows to expand significantly the range of unambiguously determined speeds of unmanned vehicles. The reasons of occurrence of false targets and their number in the mode of the parameters simultaneous measurement for the set of unmanned vehicles are identified. Using a computer experiment in LabVIEW, the probability of the unmanned vehicles true parameters determination at various ratios of the signal to noise at the input of the radar receiver in multi-target mode was investigated.