Patent ID: 6469657
Filing Date: 2002-10-22
Classification: G01S

Abstract:
A radio direction finding system for determining a direction of origin of a source of a transmitted radio frequency (RF) signal, comprising:an antenna capable of receiving said RF signal; an RF receiver coupled to said antenna system, said RF receiver having a bandwidth for receiving an entire RF band of interest in which said transmitted RF signal may lie, and outputting a detected signal; an analog-to-digital (A/D) converter coupled to said RF receiver and digitizing said detected signal to provide a series of RF samples; a Fast Fourier Transform (FFT) processor coupled to said A/D converter and performing a Fourier transform on said series of RF samples, said FFT processor producing a plurality of component frequency approximations representing frequency components of said detected signal into a plurality of FFT bins, each having a predetermined frequency size; a plurality of demodulators, each receiving the contents of a corresponding FFT bin, and subjecting said contents to a demodulation process whereby an FFT baseband sample is produced for each of said plurality of FFT bins; and a signal-to-noise ratio (SNR) processor that determines a maximum SNR from among said plurality of FFT baseband samples, and outputs an FFT baseband signal whose SNR is determined to be greatest; wherein said outputted FFT baseband signal having a greatest SNR is used as a direction finding metric for determining a direction of arrival (DOA) angle of said RF signal.