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Polarization method for navigation object selection in ship radar systems

Korban Dmytro

Zeszyty Naukowe Politechniki Morskiej w Szczecinie

2023

nr 76 (148)

17--22

This paper substantiates the method of polarization selection of navigation objects located in the zone of atmospheric formations (i.e., precipitation of different intensity and phase state), based on polarization differences in the parameters of their echo signals in a partially polarized electromagnetic wave arriving at the input of the all-polarized antenna of the ship radar polarization complex (SRPC). The partially polarized wave is represented as consisting of two polarized streams with polarization degrees m1 and m2 corresponding to the echo signals of the navigation object and atmospheric formation. The property of the partially polarized electromagnetic wave reflected from a complex object (i.e., navigation object located in the zone of atmospheric formation) is represented by real energy polarization Stokes parameters having intensity dimension. The scattering ability of the complex object is represented by the Mueller scattering matrix, the elements of which are measured by SRPC when it is sequentially irradiated with electromagnetic waves of four fixed polarizations. Polarization selection of navigation objects located in the zone of atmospheric formations uses the difference of polarization degrees of echo signals of the navigation object and atmospheric formation. The process of selection of the navigation object echo signal from the echo signal of the complex object and its observation on the screen of the SRPC indicator or computer display is based on the relationship between the degree of polarization of the electromagnetic wave and the polarization parameters of the navigation object echo signal and the atmospheric formation. The aim of this research is to develop polarization criteria of optimality of radar parameters of echo signals of partially polarized electromagnetic waves, represented by polarization degrees m1 and m2 corresponding to the navigational object and atmospheric formation observed by SRPC. As a result of the performed research, the problem of polarization selection of navigation objects located in the zone of atmospheric formations along the ship’s trajectory according to the values of the polarization degree of the navigation object echo signal is solved.

Model of the motion of a navigation object in a geocentric coordinate system

Džunda M.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

2021

Vol. 15 No. 4

791--794

In this paper we describe the creation of a model of the motion of a flying object in a geocentric coordinate system (ECEF - Earth-Centered, Earth-Fixed). Such a model can be used to investigate the accuracy and resistance of radio navigation systems to interference. The essence of the design of the model lies in the mathematical description of the motion of a flying object in a geocentric coordinate system. The flight trajectory of a flying object consists of one straight section and two turns. When creating a model, we assume a flight at a constant altitude. In this paper, we present one of the possible procedures for modelling the motion of a flying object in a geocentric coordinate system. We chose the initial coordinates of the flying object according to flightradar 24. We used the Matlab software for computer simulation.