Use of Orthogonally Linearly Polarized Waves Radiated from a Radio Beacon in the Modulation Methods for Measuring Aircra
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Radiophysics and Quantum Electronics, Vol. 63, No. 2, July, 2020 (Russian Original Vol. 63, No. 2, February, 2020)
USE OF ORTHOGONALLY LINEARLY POLARIZED WAVES RADIATED FROM A RADIO BEACON IN THE MODULATION METHODS FOR MEASURING AIRCRAFT BEARING AND ROLL V. L. Gulko and A. A. Meshcheryakov ∗
UDC 629.7.052
On the basis of using the Jones vectors and matrices, we develop the polarization-modulation method for determining the aircraft bearing and roll by the radio-beacon radiated waves with orthogonal linear polarization, which was proposed in [1]. The waves are simultaneously radiated from two points with the known coordinates, which are spaced in the measurement plane. The engineering realization of the method, which is based on using the polarization modulator placed in the single-channel microwave transmission line of an onboard receiving antenna of an aircraft, is considered. The polarization modulator has the form of the rotating segment of a circular waveguide with a built-in half-wave phase plate. Mathematical expressions, which provide a clear physical understanding of the aircraft bearing and roll relation to polarization and spectral characteristics of the resulting onboard-recorded wave field of the radio beacon in the linear polarization basis, are presented.
1.
INTRODUCTION
The amplitude, frequency, phase, or time characteristics of the radio-beacon radiated waves are conventionally used in modern radio-beacon systems for determining the angular navigation elements [2]. The navigation elements, which determine the aircraft motion with respect to its center of mass (roll and pitch) are measured using technically complicated and costly gyroscopic navigation tools [2]. The vector properties of the waves, which “bear” the navigation information are used to a lesser degree. The possibility of using the radio-beacon radiated waves with orthogonal polarization for estimating the bearing [3, 4] and roll [4] of a moving object is studied in [3, 4]. The waves with identical amplitudes and wavelengths and the known initial phases were simultaneously radiated from two points, which were spatially separated in the horizontal plane to the distance d. The roll was determined at the output of a microwave two-channel receiver from the ratio of the amplitudes of the waves with orthogonal linear polarizations, which were received onboard a moving object, and the bearing was estimated from the difference of their phases. The bearing β was calculated as an angle between the normal to the middle of the base d and the direction to the moving object by the formula λ Δϕ ± nπ, (1) β = ± arcsin 2πd where n = 0, 1, 2, . . . , λ is the wavelength, and Δϕ is the wave-phase difference at the receiving point onboard the moving object. ∗
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Tomsk State University of Control Systems and Radio Electronics, Tomsk, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 63, No. 2, pp. 124–134, February 2020. Original article submitted July 23, 2019; accepted January 30, 2020. 114 0033-8443/2
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