Wide aperature radio frequency data acquisition system

摘要

This invention relates to a wide aperture radio frequency data acquisition system which collects coherent samples from multiple points in a defined plane at the surface of the ground. The information collected can be processed with suitable algorithms to extract the bearing, frequency, and power spectra of the arriving radio frequency wavefront.PPThis system consists of an antenna system; a multi- channel receiver system incorporating mixers, filters, amplifiers, analog to digital converters, digital down converters; a digital signal processor; and a computer. The electrically short, active antennas with frequency independent response are connected to the multiple channel receiving system, one channel per antenna receiving the signal. The receiver uses two frequency conversion oscillators for coarse but accurate frequency synthesis to convert the received signal's frequency. Then, the signal is converted to a digital signal. This early conversion to a digital signal allows total intermediate frequency processing in digital mode with inherently matched filters and demodulators. The receiver is designed with low cost components to produce a very large and linear dynamic range. The digital down converter provides accurate fine tuning, bandpass filters the signal, reduces the data rate, and formats the output for extraction of amplitude and phase information from the signal.PPThe processing algorithm analyzes the data to determine arriving field strength, direction of arrival, elevation of arrival, frequency and power spectra of the signal. By choice of processing algorithm, the output data can be processed for either very fast information on brief signals, or thorough examination of data for fine frequency discrimination to less than one Hertz resolution.