A Method of Spatial Processing for a Railway Crossing Control Radar System

Abstract

Introduction. Railway crossing is a source of increased danger for vehicles and pedestrians. To increase the safety of traffic at railway crossings, radar systems based on antenna arrays (AA) can be used. The important requirements for radar at a railway crossing are a wide field of view (up to 90 degrees) and, at the same time, a high accuracy in determining coordinates. Therefore, an analysis of methods for constructing AAs and spatial processing for an automatic traffic control system at a railway crossing seems to be a relevant research task.  Aim. Design of a method for constructing the topology of an AA and spatial processing of a radar system for monitoring traffic at a railway crossing, providing a wide field of view with a high accuracy in determining the coordinates of targets.  Materials and methods. The considered method was developed based on the theory of space-time signal processing. The design of the analyzed AA topologies was carried out by the finite element method (FEM) and the finite differ-ence time domain method (FDTD) based on segments of a microstrip transmission line.  Results. A method for constructing a filled transceiver antenna array and a beamforming algorithm, which provide high angular resolution and unambiguous measurement of the target's angular coordinates in a wide field of view with relatively low computational complexity, was developed. Mathematical and electrodynamic modeling of the designed AA topologies was performed. Adjusted values of the radiation patterns (RP) of the transmitting and receiving AA were obtained, which showed good agreement with the calculated values. The main design solutions regarding the construction of AA radar for a railway crossing control system are presented to provide a wide field of view when determining the coordinates of targets.  Conclusion. It was shown that the width of the resulting RP can be reduced by several times compared to the width of the receiving RP when using two transmitting antennas located at the edges of the aperture. This approach is similar to that used in the MIMO technology, although requiring no coherence of transmission channels and use of a system of orthogonal signals. The findings determine the prospects of using the developed method.