Method and apparatus for detecting and characterizing pulse sequences

Patent metadata

Field	Value
Publication number	US-12196880-B2
Application number	US-202217714177-A
Country	US
Kind code	B2
Filing date	Apr 6, 2022
Priority date	Apr 28, 2021
Publication date	Jan 14, 2025
Grant date	Jan 14, 2025

Abstract

Method and apparatus for detecting and characterizing a pulse sequence using a finite impulse filter to determine a pulse width (PW) of pulses within the pulse sequence. The method and apparatus may also apply a histogram to the filtered pulses to determine the pulse rate interval (PRI) of pulses in the pulse sequence.

First claim

The invention claimed is:

1. Apparatus for detecting and characterizing pulse sequences comprising:
a finite impulse response (FIR) filter adapted to filter a magnitude of a received pulse sequence, where each pulse in the pulse sequence comprises a leading edge and a trailing edge, and the FIR filter generates a FIR filter output comprising a positive pulse at each leading edge and a negative pulse at each trailing edge and wherein the FIR filter is a Haar wavelet filter;
a threshold estimator adapted to generate a threshold based upon the magnitude of the input pulse sequence;
a limiter adapted to apply the threshold to the FIR filter output and generate a limiter output comprising FIR filter output that exceed the threshold;
a pulse width extractor adapted to analyze the limiter output and determine a pulse width of pulses in the input pulse sequence and
wherein a first input to the threshold estimator is an output of a moving average filter that calculates the average of the FIR filter output and a second input to the threshold estimator is an output of a moving average filter that calculates the average of the square of the FIR filter input pulse sequence.

2. Apparatus for detecting and characterizing pulse sequences comprising:
a finite impulse response (FIR) filter adapted to filter a magnitude of a received pulse sequence, where each pulse in the pulse sequence comprises a leading edge and a trailing edge, and the FIR filter generates a FIR filter output comprising a positive pulse at each leading edge and a negative pulse at each trailing edge and wherein the FIR filter is a Haar wavelet filter;
a threshold estimator adapted to generate a threshold based upon the magnitude of the input pulse sequence;
a limiter adapted to apply the threshold to the FIR filter output and generate a limiter output comprising FIR filter output that exceed the threshold;
a pulse width extractor adapted to analyze the limiter output and determine a pulse width of pulses in the input pulse sequence and
wherein a first input to the threshold estimator is an output of a moving average filter that calculates the average of the FIR filter output and a second input to the threshold estimator is an output of a moving average filter that calculates the average of the square of the FIR filter input pulse sequence,
further comprising a histogram adapted to accumulate time difference of arrival information between limiter outputs to determine pulse repetition intervals for pulses in the input pulse sequence,
wherein the pulse repetition intervals are derived from a determination of a time difference of arrival of pulses in the input pulse sequence, and
wherein the pulse repetition intervals are convolved with a weighting window to calculate a centroid to accommodate jitter in the input pulse sequence.

3. A method for detecting and characterizing a pulse sequence, comprising:
receiving an input pulse sequence having a magnitude;
filtering, using a finite impulse response (FIR) filter, the magnitude of the input pulse sequence, where each pulse in the input pulse sequence comprises a leading edge and a trailing edge and generating a filter output comprising a positive pulse at each leading edge and a negative pulse at each trailing edge;
generating a threshold based upon the magnitude of the input pulse sequence;
applying the threshold to the filter output to generate a thresholded output comprising the filter output that exceeds the threshold; and

analyzing the thresholded output to determine a pulse width of pulses in the input pulse sequence wherein the filtering is performed by a Haar wavelet filter and,
wherein generating a threshold utilizing a first input comprising an output of a moving average filter that calculates the average of the FIR filter output and a second input comprising an output of a moving average filter that calculates the average of the square of the filter output pulse sequence.

4. A method for detecting and characterizing a pulse sequence, comprising:
receiving an input pulse sequence having a magnitude;
filtering, using a finite impulse response (FIR) filter, the magnitude of the input pulse sequence, where each pulse in the input pulse sequence comprises a leading edge and a trailing edge and generating a filter output comprising a positive pulse at each leading edge and a negative pulse at each trailing edge;
generating a threshold based upon the magnitude of the input pulse sequence;
applying the threshold to the filter output to generate a thresholded output comprising the filter output that exceeds the threshold; and

analyzing the thresholded output to determine a pulse width of pulses in the input pulse sequence wherein the filtering is performed by a Haar wavelet filter and,
wherein generating a threshold utilizing a first input comprising an output of a moving average filter that calculates the average of the FIR filter output and a second input comprising an output of a moving average filter that calculates the average of the square of the filter output pulse sequence
further comprising determining a pulse repetition interval from a determination of a time difference of arrival of pulses in the input pulse sequence
further comprising accumulating, within a histogram, time-differences-of-arrivals of thresholded, hit-edited filter outputs to determine a pulse repetition interval for pulses in the input pulse sequence, and
further comprising determining the pulse repetition interval from a determination of a time difference of arrival of pulses in the input pulse sequence,
wherein the thresholded output is convolved with a weighting window to accommodate jitter in the input pulse sequence.

5. Apparatus for detecting and characterizing a pulse sequence, comprising:
a radio frequency receiver front end adapted to receive a pulse sequence and generate a quadrature magnitude of each pulse in the pulse sequence; and
one or more processors and one or more non-transient computer readable medium having instructions stored thereon which, when executed by the one or more processors, cause the one or more processors to perform operations comprising:
filtering, using a finite impulse response filter, the quadrature magnitude of the input pulse sequence, where each pulse in the input pulse sequence comprises a leading edge and a trailing edge and generating a filter output comprising a positive pulse at each leading edge and a negative pulse at each trailing edge;
generating a threshold based upon the magnitude of the input pulse sequence;
applying the threshold to the filter output to generate a thresholded output comprising the filter output that exceeds the threshold; and
a pulse width extractor adapted to analyze the thresholded output to determine a pulse width of pulses in the input pulse sequence
wherein the finite impulse response filtering is performed using a Haar wavelet filter
wherein generating a threshold utilizes a first input comprising an output of a moving average filter that calculates the average of the filter output and a second input comprising an output of a moving average filter that calculates the average of the square of the filter output pulse sequence.

Assignees

• U S Army Combat Capabilities Development Command Army Res Laboratory
• Us Army

Inventors

• Ranney Kenneth I
• Diehl William J
• Tom Kwok Foo
• Tadas Dannielle
• Tesny Neal
• Magill Andre C

Classifications

• H04K3/822

  by detecting the presence of a surveillance, interception or detection · CPC title

• H04K3/45

  characterized by including monitoring of the target or target signal, e.g. in reactive jammers or follower jammers for example by means of an alternation of jamming phases and monitoring phases, called "look-through mode" · CPC title

• H04K3/80

  Jamming or countermeasure characterized by its function · CPC title

• H04K3/22

  including jamming detection and monitoring · CPC title

• G01S7/285 Primary

  Receivers · CPC title