Detection range of airborne objects by broadband active-passive radar systems

Abstract

In the interests of searching and observing aerial objects with low levels of background contrast of secondary electromagnetic radiation and signals of on-board radio-electronic means, it is required to use active-passive radar systems with identification of the belonging of unmasking signs identified by heterogeneous information sensors to one object. When constructing procedures for joint processing of information signals, the issues of determining the range of active and passive search (observation) channels become important when implementing measures to reduce the reflective properties and structural and energy secrecy of the operation of electronic equipment of aircraft. To establish the boundaries of the area controlled by the active-passive radar system, it is necessary to use energy equations for transmitting and receiving broadband signals with a priori indefinite arrival time in a radio channel with scattering and a direct radio channel. The equations are found by integrating spectral equations for inharmonic wave processes propagating in free space in the band of cyclic operating frequencies when approximating the partial directional coefficients of antennas and partial effective scattering areas of objects by power functions of cyclic frequencies. The goal of the article is identification of patterns of influence of object reflective properties and characteristics of airborne radio sources on the range of active-passive radar systems. Using energy equations of transmission-reception of non-harmonic wave processes in a radio channel with scattering and direct radio channel, analytical expressions for determining probabilistic characteristics of signal detection with a priori indefinite arrival time, the possibilities of detecting air objects by broadband active-passive radar systems have been investigated. Ratios of ranges of detection of objects have been found based on the results of receiving and processing of information signals of radar stations and intrinsic radiation of airborne radio-electronic equipment. The revealed regularities of the influence of the object reflective properties and the characteristics of airborne radio sources on the range of radar stations and passive radar complexes allow us to make a rational choice of parameters of active-passive radar system designs in order to achieve the required indicators of the effectiveness of air space control. The energy equations of transmission and reception of broadband signals in radio channels form the basis for the development of proposals to ensure the covert use of aircraft.