Direction finding of electromagnetic radiation sources using the volumetric phased arrays consisting of the small number of elements

Abstract

Problem statement. This article proposes a method to measure the bearing of electromagnetic radiation sources in the conditions of passive interference with multipath propagation and in the conditions of using "rough" (small number of elements) statistics taking into account particular design features of the direction finder located on a mobile object. The technical design of an adaptive direction finder (ADF) with a small number of channels M = 7 and “short spatial samples” m = 2 (bases) is substantiated, which leads to reducing hardware and software costs. Target. Determine the method of direction finding of electromagnetic radiation sources by volumetric phased arrays consisting of the small number of elements, which allow for the presence of passive interference with multipath radiation of electromagnetic radiation sources, and include spatial digital filters (DF) of a low order r = 2. Results. The problem of measuring the bearing of electromagnetic radiation sources under the conditions of correlated multipath passive interference and limited hardware and computing resources was solved. Direction finder includes a 7-element monopulse direction finder, which was built according to a sequential scheme at the nodes of a volumetric hexagonal grid with an equivalent spatial quantization step of 0.5l, forming programmable small-sized bases with a size of no more than l using the method of multiplexing (HF switching). Practical significance. The relevance of the proposed approach is substantiated due to the need to notch "multipath components", parasitic reflections from local objects surrounding the adaptive direction finder, and reduce the instrumental error in bearing measurement. A new approach to the construction of a volumetric phased array of an adaptive direction finder is proposed. Novelty. The synthesis of the optimal estimate is based on the principle of “whitewashing” passive correlated interference and the maximum likelihood method, which guarantees the achievement of potential direction finding accuracy in the conditions of using rough statistics that reduce hardware and software costs.