Method and apparatus for target discrimination within return signals
View Patent ↗A template representing a desired target is applied to response signals from an area including a plurality of targets and illuminated by electromagnetic radiation. The response signals include poles or damped sinusoids representing resonances (e.g., resonant frequencies) distinctly associated with each of the targets within the area. An embodiment of the present invention utilizes pole or damped sinusoid frequencies of a desired target to construct the template or comb-like pattern that is compared to the mixture of pole frequencies within the response signals from the area. The comparison yields a resulting score that indicates the presence of the desired target within the area.
1. A system for discriminating targets within return signals comprising:
a transmitter to transmit signals to illuminate an area including at least two targets;
a receiver to receive said transmitted signals reflected and returned from said area; and
a processor to process said return signals to determine the presence of a desired target within said area, wherein said processor includes:
a storage unit to store a template including characteristics of damped sinusoids representing a set of resonances distinctly associated with said desired target; and
a detection module to extract information from said return signals related to damped sinusoids representing sets of resonances associated with said at least two targets and to compare said template with said extracted information from said return signals to determine the presence of said desired target within said area.
2. The system of claim 1 , wherein said template includes amplitude values corresponding to frequencies of said damped sinusoids.
3. The system of claim 2 , wherein said detection module includes:
a waveform module to extract said information related to damped sinusoids within said return signals;
a score module to determine a score value by summing amplitude values from said template corresponding to damped sinusoid frequencies within said extracted information; and
a compare module to compare said score value to a threshold to determine the presence of said desired target within said area.
4. The system of claim 3 , wherein said waveform module utilizes a Matrix Pencil Method technique to extract said information.
5. The system of claim 3 , wherein said threshold is determined based on an operating point within a Radio Operating Characteristics curve generated in accordance with said template.
6. The system of claim 3 , wherein said waveform module includes:
a sampling module to sample said return signals within a sampling window of a predetermined interval, wherein said information is extracted from said sampled return signals.
7. The system of claim 6 , wherein said sampling module samples said return signals within a stationary sampling window.
8. The system of claim 6 , wherein said sampling module samples said return signals within a moving sampling window to scan said return signals.
9. The system of claim 1 , wherein said template is produced based on actual measurements of said desired target.
10. The system of claim 1 , wherein said template is mathematically derived based on return signals from said desired target.
11. The system of claim 1 , wherein said template includes amplitude values corresponding to frequencies and damping constants of said damped sinusoids.
12. The system of claim 1 , wherein said storage unit stores a plurality of templates each associated with a corresponding target, and said detection module determines the presence of a plurality of targets within said area by comparing each template associated with one of said plurality of targets to said extracted information.
13. A method of discriminating targets within return signals reflected from an area including at least two targets and illuminated by transmitted signals, said method comprising:
(a) extracting information from said return signals related to damped sinusoids representing sets of resonances associated with said at least two targets; and
(b) comparing a template associated with a desired target with said extracted information from said return signals to determine the presence of said desired target within said area, wherein said template includes characteristics of damped sinusoids representing a set of resonances distinctly associated with said desired target.
14. The method of claim 13 , wherein said template includes amplitude values corresponding to frequencies of said damped sinusoids.
15. The method of claim 14 , wherein step (a) further includes:
(a.1) determining a score value by summing amplitude values from said template corresponding to damped sinusoid frequencies within said extracted information; and
(a.2) comparing said score value to a threshold to determine the presence of said desired target within said area.
16. The method of claim 15 , wherein step (a.2) further includes:
(a.2.1) determining said threshold based on an operating point within a Radio Operating Characteristics curve generated in accordance with said template.
17. The method of claim 13 , wherein step (a) further includes:
(a.1) extracting said information by applying a Matrix Pencil Method technique to said return signals.
18. The method of claim 13 , wherein said template is produced based on actual measurements of said desired target.
19. The method of claim 13 , wherein said template is mathematically derived based on return signals from said desired target.
20. The method of claim 13 , wherein step (a) further includes:
(a.1) sampling said return signals within a sampling window of a predetermined interval, wherein said information is extracted from said sampled return signals.
21. The method of claim 20 , wherein step (a.1) further includes:
(a.1.1) sampling said return signals within a stationary sampling window.
22. The method of claim 20 , wherein step (a.1) further includes:
(a.1.1) sampling said return signals within a moving sampling window to scan said return signals.
23. The method of claim 13 , wherein said template includes amplitude values corresponding to frequencies and damping constants of said damped sinusoids.
24. The method of claim 13 , wherein step (b) further includes:
(b.1) determining the presence of a plurality of targets within said area, wherein each of said plurality of targets is associated with a corresponding template and each template associated with one of said plurality of targets is compared to said extracted information to determine the presence of that target within said area.