Design and implementation of equilateral triangle array digital direction finding system

Abstract

In this work, a scheme of an equilateral triangle array digital direction finding system is proposed, which implements the online real-time direction finding task for an airborne system. The three-elements equilateral triangle array can be used for calibrating the channel errors and eliminating the DOA (direction of arrival) fuzzy problem of the two-elements linear array, which is greatly reduced the system complexity and suitable for portable requirement. At the same time, the project adopts field programmable gate array (FPGA) to process the sample data in parallel mode, including data quadrature demodulation and multiple signal classification (MUSIC) algorithm. The hardware implementation of MUSIC algorithm makes the system more flexible and faster than software implementation. The experimental results show that the deviation is less than 0.5 degrees with over 64 snapshots and the time is less 6ms with 256 snapshots, and then the program can complete the MUSIC algorithm accurately with high speed.