Radar Characteristics of Precipitation Affecting the Tracking of Ship’s Radar Objects

In this paper, we consider the possibility of using the radar characteristics under precipitation conditions in order to reduce the echo signal’s negative impact on the object tracking performed by the ship’s radar. Precipitation particles’ size, state (solid or liquid phase), shape, and the factors that determine their combined action play an important role in echo signal formation. The rain particles’ size in comparison with the wavelength of the ship’s radar may contribute to the creation of a larger or smaller noise echo signal on the ship’s radar display. This signal’s power in the Rayleigh scattering area towards the radar is characterized by the effective scattering area. Raindrops represent a combination of randomly located reflectors. Their scattering properties depend on spatial distribution and movement regularity. At the same time, the radar characteristics of clouds with precipitation generated by them can be used in ship radars to determine the intensity of the atmospheric process along the ship’s route. The uncertainty in determining the power attenuation of an electromagnetic wave emitted by a ship’s radar antenna and passing through the precipitation zone can be reduced by the simultaneous use of two wavelengths on which a ship’s radars operate. The presented uncertainty function characterizes a narrow-band polarized scattered signal in regard to radar information about the distance to the sea object and the scatterer's speed. It characterizes the matched multidimensional coherent filter’s properties. This filter provides optimal echo reception against the background of an uncorrelated precipitation echo signal. The matched filter belongs to the class of optimal linear filters according to the criterion of the maximum signalto-noise ratio and is the main element for radar detection devices in the ship radar, which is optimal according to the Neyman-Pearson criteria. Keywords: radar characteristics of precipitation, precipitation intensity, effective scattering area, precipitation particle diameter, dielectric constant, energy attenuation, radio waves, wavelength.