United States of America as Represented by the Secretary of the Air Force

Other

David L Sharpin

James B Tsui

Rudy L Shaw

Daniel R Zahirniak

Timothy W Fields

The present invention documents a digital channelized receiver for signal intercept applications. A hardware efficient implementation of a uniform filter bank in which the number of filters, K, is greater than the decimation factor, M, is provided. By optimizing the filter bank frequency response, in conjunction with K and M, the proposed invention allows a simple channel arbitration logic to be implemented. In addition, the present invention provides reliable instantaneous frequency measurements and parameter estimates across the desired frequency range while reducing the data processing speed requirements by a factor of M.

Hardware efficient digital channelized receiver

Disclosed is a method to extract the periodic properties (or Pulse Repetition Intervals (PRIs)) of radar signals whose time-of-arrival at an airborne platform have been time tagged by an Electronic Warfare (EW) receiver. The PRIs are determined using a modified Discrete Fourier Transform (DFT) written as ##EQU1## where k represents the frequency components, the T.sub.i are the individual Time-Of-Arrival (TOA) data values and N is the last TOA value collected. Disclosed are three possible methods of reducing the number of computations involved with the modification of the Discrete Fourier Transform (DFT) equation to facilitate its use with Radar Time-Of-Arrival (TOA) to extract periodic properties of radar signals. This is particularly applicable to radar pulse trains which are interleaved in time and where each individual pulse train may be staggered or jittered in time so that a time domain deinterleaving scheme must be employed. A spectral estimator can be computed by taking the modulus of the DFT of the time series data and extending the periodogram estimator by making a slight modification of the DFT equation.

Spectral estimation of radar time-of-arrival periodicities

The method provides the capability to estimate the angle-of-arrival (AOA) of radar pulses with respect to a ground or airborne based platform. It utilizes a spectral estimation technique which extracts the periodic properties of radar signals whose time-of-arrivals (TOAs) have been tagged by an Electronic Warfare receiver. The method can be used in a multiple signal environment and can separate and individually measure AOA of emitters that are spatially very close but have incommensurate Pulse Repetition Intervals (PRIs).

Angle-of-arrival measurement via spectral estimation of radar

A technique covered by patent applicaton S.N. 07/672,309 divides power of an input signal to two A/D converters. A processor receives the outputs of the two A/D converters. The input signal is subjected to a known delay .tau. for one of the converters, and both original and delayed signals are sampled simultaneously. Both sampled signals are Fourier transformed and the phase and amplitudes calculated, using the expressions:

Growing community of inventors

Springfield, OH, United States of America

David L Sharpin