Phase Direction Finders Research Articles

Вопросы разрешающей способности фазовых радиопеленгаторов с антенными системами в виде линейных решеток

Вопросы разрешающей способности фазовых радиопеленгаторов с антенными системами в виде линейных решеток

Rejection of abnormally large direction-finding errors in the process of resolving the measurement ambiguities in phase direction-finders implementing the maximum-likelihood method

An algorithm for improvement of the accuracy of small-sized phase direction finders by rejecting abnormally large errors in the process of resolving the measurement ambiguities is proposed. Design relationships that characterize the efficiency of the algorithm are obtained. The theoretical propositions are validated by digital simulation of the operation of a three-base direction finder and by its full-scale test.

Modular arithmetic application to calculate the azimuth for phase direction finder

Introduction. Phase finders are designed for precise determination of the radiation source angular position. In such systems, an important task is to avoid the ambiguity measuring the signalphase shift exceeding . A new way to solve the problem associated with the use of residue number system (RNS) is proposed. Problem statement. Defined azimuth of radiation source fluctuations relative to the two bases linear receiving antenna. It is necessary to define the conditions under which the problem of estimating the azimuth based on the measurement of signals phase shifts between antenna elements is reduced to the recovery of a whole number from its RNS residues. Theoretical results. The possibility of RNS using for phaze multiscale systems based on common property - the modular nature both numerical data RNS representations and phase measurements. It is shown that to bring the azimuth determining problem to the problem of reconstructing the whole number from its RNS residues for two bases finder is necessary: firstly, to select the modules RNS as a pair of relatively prime numbers; secondly, to select the antenna base proportional RNS modules; thirdly, to select the quanta of measuring the phase shift signal is inversely proportional to the value of the RNS modules: An example of calculating the azimuth of the direction finder for the phase two bases, which confirms the correctness of the proposed method. Conclusion. The possibility of using RNS phase direction finder is implemented by selecting an antenna base and phase shift quantum measurement proportional to the RNS modules. In this case, the process of eliminating ambiguity measurement acquiring a new quality – the ability to identify and correct azimuth blunders. A new data processing algorithm and it's new property can significantly reduce the probability of serious errors in the phase finders.

Method for formation of azimuth mark of phase direction finder

A method is proposed for processing the signals of automatic phase direction finders, enabling the formation of an azimuth mark by means of detuning according to the switching frequency of a dipole of the antenna system. Modeling results are presented.

Estimation of the Influence of Electromagnetic-Wave Scattering by a Circular Array of Capacitively Loaded Monopoles on the Accuracy and Resolution of the Phase Direction Finder

The influence of the field reflection in an antenna system on the accuracy and resolution of the phase direction finder is studied on the basis of solving the problem of electromagnetic-wave scattering by a circular array of monopoles with capacitance loads in the form of thin metal discs located near an infinite perfectly conducting plane. We formulate proposals on the choice of the number of antenna elements and the array radius, which ensure the potential accuracy and resolution of the direction finder for meter wavelengths.

Angular characteristics of radio pulses reflected from the subpolar ionosphere

This paper presents the results derived by measuring angular spectra of HF-radio pulses reflected from the subpolar ionospheric F2-region (62°N) using vertical-incidence soundings and a phase direction finder with Doppler filtering. The results correspond to three main types. One is the classical mirror reflection from the undisturbed ionospheric F2-region, typical of mid-latitudes (deviations from zenith do not exceed 3°; the angular spectrum width is less than 1°). The second type includes oblique diffuse reflections with a deviation from zenith of from 10 to 45°. The azimuth of arrival of these reflections is distributed in the range from 0 to 360°, the angular spectrum width is from 5 to 10°, and the range varies from 400 to 600 km. The third type includes anomalous mirror reflections with small deviations from zenith (not greater than 3°) but with substantially larger detection ranges (for example, 500km) as compared with the main reflections (250–300 km).