On the Doppler effect in radar

The possibilities of simultaneous use of the longitudinal and transverse Doppler effects have been analyzed, and expressions have been derived for the corresponding beat frequencies between the emitted and received signals. As a rule, only the longitudinal Doppler effect is used in modern radio engineering systems, which makes it possible to determine the radial component of the object's speed. In addition, there are situations for which it is generally impossible to determine the speed of an object without taking into account the transverse Doppler effect. The authors analyze the fundamental possibilities of improving the functioning of radar stations that simultaneously use both types of Doppler effects – longitudinal and transverse ones – making it possible to determine the total speed of the observed object in any situations. The authors have analyzed the longitudinal and transverse Doppler effects for the case of a moving emitting object, derived expressions for the Doppler shift and expressions for the beat frequency in the case of an active radar station for both types of Doppler effects, which make it possible to obtain the value of the object's speed in any situations. Variants of determining the total speed of a moving object have been proposed, accounting the determination of its radial and tangential components. Idealized situations in which only one of the Doppler effects appeared have been considered.

Dependence between the accuracy of target designation to an onboard missile radar station and errors related to determination of the target and missile coordinates by a ground radar system

This article investigates the dependence between the accuracy of target designation issued by a ground radar system to an onboard radar station based on the measured target and missile coordinates and on the relative missile position (relative to the radar and the target). Simulation and calculation methods are proposed for estimating the accuracy of target designation in terms of the observation angle and the range and speed of the target taking into account both the errors in measuring the target and missile coordinates by a ground radar system and the relative position of the missile. The influence of the errors in measuring the target and missile coordinates and the relative position of the missile on the target designation accuracy is investigated. The problem of tracing the optimal trajectory of missile guidance to the target is formulated taking into account the errors of target designation to an onboard radar station and other factors.

Optimization of searching for moving targets of a multifunctional radar station

A method for optimizing the process of searching for an unknown number of moving targets in conditions of stochastic uncertainty is proposed, which allows to significantly reduce the average time of their finding by a multifunctional radar device equipped with an antenna array. More effective is the optimal managed search, in which the order of viewing different directions is determined in the search process depending on the results of already performed views. One of the important areas of further improvement of radar technology is the transition to antenna arrays with digital beamforming based on adaptive signal processing directly in the elements of the digital antenna array (DAA).