VEHICLE IDENTIFICATION SYSTEM AND METHOD

• US 20140340192A1
• Filed: 05/16/2013
• Published: 11/20/2014
• Est. Priority Date: 05/16/2013
• Status: Active Grant

• Current Assignee: BOOZ Allen & Hamilton Incorporated (BOOZ Allen Hamilton Holding Corporation)
• Original Assignee: BOOZ Allen & Hamilton Incorporated (BOOZ Allen Hamilton Holding Corporation)
• Inventors: YAMADA, Randy M., LeDoux, David C., AYERS, Brandon M., STEINHART, Allan O.
• Granted Patent: US 9,354,265 B2
• Time in Patent Office: Days
• US Class Current: 340/5.8
• CPC Class Codes: G01R 29/0814 Field measurements related to measuring influence on or from apparatus, components or humans EMC, EMI and similar testing in general G01R31/001, e.g. in ESD, EMI, EMC, EMP testing, measuring radiation leakage; detecting presence of micro- or radiowave emitters; dosimetry; testing shielding; measurements related to lightning
• CPC Class Codes: G01R 29/0878 Sensors; antennas; probes; detectors wave guide measuring sections G01R1/24
• CPC Class Codes: G01R 31/001 Measuring interference from external sources to, or emission from, the device under test, e.g. EMC, EMI, EMP or ESD testing measuring electromagnetic fields G01R29/08; circuits for generating HV pulses in dielectric strength testing G01R31/14
• CPC Class Codes: G01R 31/007 using microprocessors or computers

Abstract

Exemplary systems and methods are directed to establishing a signature for a device emitting electromagnetic radiation (EMR). The system includes a radio frequency (RF) receiver, a signal processor, and a signature generator. The RF receiver samples detected EMR, generate pulses having characteristics that are a function of the EMR, and select generated pulses in a spectral band having energy above a predetermined threshold. The signal processor establishes a set of correlated pulses, computes a vector space associated with the set of correlated pulses, and compares each pulse in the set of correlated pulses to a basis of the vector space for establishing a device signature, and associates pulses having a threshold percentage of energy within the basis in a database with a device identifier.

Claims

1. A system for establishing a signature of a device emitting electromagnetic radiation (EMR), comprising:

a radio frequency (RF) receiver configured to sample detected EMR, generate pulses having characteristics that are a function of the EMR, and select pulses in a spectral band having energy above a predetermined threshold;

a signal processor configured to establish a set of correlated pulses from among the selected pulses; and

a signature generator configured to compute a vector space associated with the set of correlated pulses, compare each pulse in the set of correlated pulses to a basis of the vector space for establishing a device signature, and associate pulses having a threshold percentage of energy within the basis in a database with a device identifier.

2. The system of claim 1, wherein the signature generator is configured to identify a device by processing the EMR emitted by the device and to compare the processed EMR to plural device signatures stored in memory, wherein each device signature occupies an associated subspace.

3. The system of claim 2, wherein the processed radiation includes at least one pulse of the device, the at least one pulse being correlated to a stored device signature when a total energy of the at least one pulse within the associated subspace is above a predetermined threshold.

4. The system of claim 1, wherein the RF receiver is configured to convert received pulses to a frequency domain using a Fast Fourier Transform (FFT).

5. The system of claim 4, wherein each FFT has a resolution greater than 2.7 MHz/bin.

6. The system of claim 4, wherein each FFT comprises:

frequency bins, and the RF receiver is configured to select a range of frequency bins within a predetermined interval.

7. The system of claim 6, wherein the predetermined interval is a window within which spectral energy is summed.

8. The system of claim 6, wherein the signal processor is configured to compute an FFT having plural frequency bins for each selected pulse, and to select a second range of frequency bins using another predetermined interval.

9. The system of claim 8, wherein the signal processor is configured to band pass filter the second range of frequency bins and to zero all negative frequency bins resulting from the filtering.

10. The system of claim 9, wherein the signal processor is configured to convert each pulse associated with a filtered frequency bin from a frequency domain to a time domain.

11. The system of claim 10, wherein the signal processor is configured to align each converted pulse by shifting the pulse in time so that a maximum magnitude value of the converted pulse will correspond to a predetermined sample index.

12. The system of claim 1, wherein the signal processor is configured to normalize the correlated pulses so that a sum of squared magnitudes of each pulse in the set of correlated pulses is equal to one.

13. The system of claim 1, wherein the signature generator is configured to compute a first set of orthogonal vectors as the basis of the vector space using the set of correlated pulses.

14. The system of claim 13, wherein the signature generator is configured to:

compute a dot product between each pulse in the set of correlated pulses and each orthogonal vector;

square each dot product; and

sum the squares of the dot products.

15. The system of claim 14, wherein the signature generator is configured to reject a pulse if the sum of squares of the dot products for the pulse is below a predetermined threshold.

16. The system of claim 15, wherein the signature generator is configured to iteratively compute a second set of orthogonal vectors, and reject a pulse based on the sum of squares of the dot products until no further pulses are rejected.

17. The system of claim 15, configured to establish the signature of a device which is a vehicle used on at least one of land, water, and air.

18. A method for establishing a signature for a device emitting electromagnetic radiation (EMR), comprising:

detecting EMR emitted from the device;

sampling the EMR to generate pulses having characteristics that are a function of the EMR;

selecting the generated pulses which have energy above a predetermined threshold as a set of correlated pulses;

calculating a vector space based on the energy of each pulse in the set of correlated pulses; and

establishing a signature of the EMR emitting device by comparing each pulse in the set of correlated pulses to a basis of the vector space, wherein each pulse in the signature has a threshold percentage of energy within an associated subspace of the vector space basis.

19. The method of claim 18, wherein calculating the vector space includes:

aligning the selected pulses to establish the set of correlated pulses;

generating a set of orthogonal vectors based on the set of correlated pulses to establish the vector space; and

calculating the basis for the device based on a magnitude of each pulse in the set of correlated pulses.

20. The method of claim 19, comprising:

normalizing the aligned pulses so that a sum of squared magnitudes of each pulse in the set is equal to one.

21. The method of claim 18, comprising:

converting the pulses to a frequency domain using a Fast Fourier Transform (FFT).

22. The method of claim 21, comprising:

selecting a range of frequency bins within a predetermined interval.

23. The method of claim 22, wherein the predetermined interval is a window, the method comprising:

summing spectral energy of the pulses within the window.

24. The method of claim 22, wherein the predetermined interval is a first predetermined interval, the method comprising:

computing an FFT having plural spectral bins on each pulse; and

selecting a second range of spectral bins using a second predetermined interval.

25. The method of claim 24, comprising:

filtering the second range of frequency bins and zeroing all negative frequency bins resulting from the filtering.

26. The method of claim 25, comprising:

converting a filtered pulse from the frequency domain to the time domain.

27. The method of claim 26, comprising:

aligning the filtered pulse by shifting the pulse in time so that a maximum magnitude value of the filtered pulse corresponds to a sample index.

28. The method of claim 19, wherein establishing the signature of the device includes:

computing a set of orthogonal vectors using the set of correlated pulses to establish a signature basis for the set of pulses.

29. The method of claim 28, comprising:

computing a dot product between each pulse in the set of pulses and each orthogonal vector;

squaring each dot product; and

summing the squares of the dot products.

30. The method of claim 29, comprising:

rejecting a pulse if the sum of squares of the dot products for the pulse is below a predetermined threshold.

31. The method of claim 18, wherein each device signature occupies an associated subspace.

32. The method of claim 31, wherein the device is a known device, the method comprising:

generating at least one pulse from EMR emitted from an unknown device; and

projecting the at least one pulse of the unknown device onto each device signature, wherein the device signature having a largest percentage of total energy of the at least one pulse within the associated subspace is selected as a device classification.

33. The method of claim 32, comprising:

computing a vector space and vector space basis for each device signature; and

calculating a dot product between the at least one pulse of the unknown device and each of the vectors in a respective set of a device signatures to determine a fraction of energy of the at least one pulse of the unknown device in a subspace of the device signature.