DETECTION OF TRANSIENT SIGNALS IN DOPPLER SPECTRA
First Claim
1. A method of detecting transient signals in a power spectrum comprising a measured signal and noise, the method comprising the steps of:
- generating a power spectrum from the measured signal and noise;
determining, from the power spectrum, peaks in the power spectrum;
generating at least one histogram of moments for peaks in the power spectrum;
normalizing the at least one histogram of the moments by its area to produce a measured Probability Density Function (PDF);
comparing a difference between the measured PDF with a predetermined PDF to determine if a signal is present.
1 Assignment
0 Petitions
Accused Products
Abstract
Signal processing is used to detect transient signals in the presence of noise. Two embodiments are disclosed. In both embodiments, the time series from a remote sensor is broken into a number of short time series. The power spectrum of each short time series are then calculated along with the mean noise level. The moments of each peak in every power spectrum are calculated and the peak with the largest power selected from each power spectrum. A histogram of the moments from these selected peaks is generated and normalized to become a measured PDF. In addition, a pre-determined PDF is derived, in the same method as above, from theoretically calculated noise, numerically simulated noise, or measured noise. Comparison between the measured and pre-determined PDF'"'"'s establish the detection of a transient signal. The first embodiment compares the area between the measured and pre-determined PDF'"'"'s against a threshold to determine detection. In a second embodiment, the differences between the measured and pre-determined PDF'"'"'s are weighted and summed to form a score. This score is compared to a threshold to determine detection.
-
Citations
20 Claims
-
1. A method of detecting transient signals in a power spectrum comprising a measured signal and noise, the method comprising the steps of:
-
generating a power spectrum from the measured signal and noise; determining, from the power spectrum, peaks in the power spectrum; generating at least one histogram of moments for peaks in the power spectrum; normalizing the at least one histogram of the moments by its area to produce a measured Probability Density Function (PDF); comparing a difference between the measured PDF with a predetermined PDF to determine if a signal is present. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. An apparatus for detecting transient signals in Doppler spectra comprising a measured signal and noise, the apparatus comprising:
-
a radar receiver for receiving a radar signal comprising a measured signal and noise; a Fast Fourier Transform, coupled to the radar receiver, for generating a power spectrum from the magnitude squared of the Fast Fourier Transform of the radar signal; a histogram generator, coupled to the moment calculator, for selecting a largest signal power peak from each individual power spectrum, generating a histogram of the moments, and normalizing the histogram by its area to produce a measured PDF. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
-
Specification