Emitter proximity identification

• US 7,944,389 B1
• Filed: 07/09/2009
• Issued: 05/17/2011
• Est. Priority Date: 07/09/2009
• Status: Active Grant

• Current Assignee: Harris Global Communications, Inc. (L3Harris Technologies, Inc.)
• Original Assignee: ITT Manufacturing Enterprises, Inc. (ITT, Inc.)
• Inventors: Lu, Ning H., Steensma, Peter D.
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Brainard; Timothy A
• Application Number:
  US12/500,256
• Time in Patent Office: 677 Days
• Field of Search: 342/13, 342/42, 342/190, 342/191, 702/5, 702/127
• US Class Current: 342/13
• CPC Class Codes: F41H 11/136 Magnetic, electromagnetic, acoustic or radiation systems, e.g. ground penetrating radars or metal-detectors
• CPC Class Codes: G01S 11/06 using intensity measurements
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence

Abstract

Systems and methods for monitoring and classifying RF emissions in the field include storing an electronic signature map (ESM) of a selected geographic area, where the electronic signature map includes previously detected emitter closeness measures (ECMs) in the selected geographic area. The ECMs are representative of detected sources of radio frequency energy. A RF energy emission is detected, a new ECM for that RF energy emission is created, and that the new ECM is compared with the ECMs in the ESM. That comparison may help to determine whether the RF energy emission should be considered a threat.

Claims

1. A method, comprising:

storing an electronic signature map (ESM) of a selected geographic area, the electronic signature map comprising previously calculated emitter closeness measures (ECMs) in the selected geographic area, wherein the ECMs are representative of detected sources of radio frequency energy;

detecting a radio frequency energy emission;

creating a new ECM for the radio frequency energy emission based on relative measures of the radio frequency emission;

comparing the new ECM with the ECMs in the electronic signature map;

determining whether the new ECM should be considered a threat; and

geo-locating a position of an emitter represented by the new ECM.

2. The method of claim 1, wherein the geographic area comprises a road via which vehicles traverse.

3. The method of claim 1, wherein detecting comprises detecting with a single antenna only.

4. The method of claim 1, wherein detecting comprises detecting with multiple antennas.

5. The method of claim 1, wherein detecting comprises detecting continuous wave radio frequency energy.

6. The method of claim 1, wherein creating a new ECM comprises calculating a rate of received signal strength (RSS) change (RRSSC) versus distance.

7. The method of claim 6, further comprising designating the radio frequency emission as a potential radio frequency emitter threat when RRSSC>

2 dB/10 m.

8. The method of claim 1, wherein creating a new ECM comprises calculating a rate of bearing change (RBC) versus distance.

9. The method of claim 8, further comprising designating the radio frequency emission as a potential radio frequency emitter threat when RBC>

3°

/10 m.

10. The method of claim 1, further comprising presenting the position of the emitter on a map.

11. The method of claim 1, further comprising transmitting the new ECM from a first vehicle to a second vehicle.

12. The method of claim 1, further comprising transmitting the new ECM from a vehicle to a base station.

13. A method for monitoring sources of radio frequency (RF) energy in the field, comprising:

storing an emitter signature map (ESM) comprising a plurality of emitter closeness measures (ECMs), wherein each ECM represents a relative measure of a signal strength and location from which a source of RF energy is detected;

detecting a RF emission in the field;

comparing metrics of the RF emission to the plurality of ECMs;

identifying whether the RF emission should be considered a potential threat; and

geolocating a source of the RF emission.

14. The method of claim 13, further comprising eliminating ambiguities with respect to the RF emission using the ESM.

15. The method of claim 13, further comprising mitigating multi-path effects with respect to the RF emission.

16. The method of claim 13, further comprising sharing information with respect to the RF emission with another platform.

17. The method of claim 13, further comprising calculating a rate of received signal strength (RSS) change (RRSSC) versus distance.

18. The method of claim 17, further comprising designating the RF emission as a potential radio frequency emitter threat when RRSSC>

2 dB/10 m.

19. The method of claim 13, further comprising calculating a rate of bearing change (RBC) versus distance.

20. The method of claim 19, further comprising designating the RF emission as a potential radio frequency emitter threat when RBC>

3°

/10 m.

21. A system for monitoring radio frequency emitters in the field, comprising:

an analog to digital (A/D) converter configured to receive an analog radio frequency or intermediate frequency signal and output a digital signal;

a digital signal processing module configured to receive the digital signal and output metrics indicative of the RF signal;

an electronic signature map (ESM) database, the ESM database configured to store previously-calculated emitter closeness measures (ECMs) in a selected geographic area, wherein the ECMs are representative of detected sources of radio frequency energy; and

an emitter proximity identification module configured to

create a new ECM for the radio frequency signal;

compare the new ECM with the ECMs in the ESM database;

determine whether the new ECM should be considered a threat; and

geo-locate a position of an emitter represented by the new ECM.