Search and rescue method and system

• US 9,476,963 B2
• Filed: 04/25/2011
• Issued: 10/25/2016
• Est. Priority Date: 04/23/2010
• Status: Expired due to Fees

• Current Assignee: David Cyganski, R. James Duckworth
• Original Assignee: David Cyganski, R. James Duckworth
• Inventors: Cyganski, David, Duckworth, R. James
• Primary Examiner(s): Issing, Gregory C
• Application Number:
  US13/642,319
• Publication Number:
  US 20130099975A1
• Time in Patent Office: 2,010 Days
• US Class Current: 1/1
• CPC Class Codes: G01S 11/06 using intensity measurements
• CPC Class Codes: G01S 3/146 by comparing linear polarisation components
• CPC Class Codes: G01S 3/28 using amplitude comparison of signals derived simultaneously from receiving antennas or antenna systems having differently-oriented directivity characteristics
• CPC Class Codes: G01S 5/0205 Details
• CPC Class Codes: G08B 21/0263 System arrangements wherein the object is to detect the direction in which child or item is located
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00

Abstract

A method for locating a transmitter using a receiver which include, but are not limited to the steps of transmitting a plurality of distinctive and orthogonally polarized signals from a transmitter; receiving the transmitted signals at a pair of separated antennas; demodulating the distinctive orthogonal signals received at each of the pair of separated antennas; and determining a direction to the transmitter from the signals received at the pair of antennas. The system for determining the location of a transmitter using a receiver includes, but is not limited to, having a transmitter adapted for orthogonally transmitting a plurality of distinctive signals; a receiver having a pair of separated antennas for receiving the orthogonally transmitted signals; separate demodulators in the receiver for each antenna of the pair of separated antennas for demodulating the distinctive signals; and signal processing circuitry in the receiver adapted for using the demodulated distinctive signals for determining a direction to the transmitter.

Claims

1. A method for locating a transmitter using a receiver, comprising the steps of:

transmitting at least three distinctive and mutually orthogonal signals from a transmitter, the at least three distinctive and mutually orthogonal signals having a frequency of most 200 kHz;

receiving, in a near field region, the transmitted at least three distinctive and mutually orthogonal signals at each one a pair of separated antennas;

hereinafter referred to as the at least three distinctive and mutually orthogonal signals received at said each one of the pair of separated antennas;

each one of the pair of separated antennas being located at separate ends of a linear structure;

the linear structure being configured to be handheld;

demodulating the at least three distinctive and mutually orthogonal signals received at said each one of the pair of separated antennas;

producing at least three demodulated signals corresponding to said each one of the pair of separated antennas;

obtaining, after demodulating, for said each one of the pair of separated antennas, from the at least three demodulated signals corresponding to said each one of the pair of separated antennas, a transmitting antenna orientation invariant signal corresponding to said each one of the pair of separated antennas;

determining a direction to the transmitter from the transmitting antenna orientation invariant signal obtained for said each one of the pair of separated antennas; and

providing an indicator signal indicating proximity and distance to the transmitter;

whereby the method enables rescue of a first responder in almost any type of building including fully metallic buildings.

2. The method of claim 1, wherein the step of obtaining includes combining, for said each one of the pair of separated antennas, signal amplitude levels of the at least three demodulated signals corresponding to said each one of the pair of separated antennas;

thereby obtaining for a combined signal amplitude level corresponding to said each one of the pair of separated antennas.

3. The method of claim 2, further comprising indicating to a user a difference between the combined signal amplitude level corresponding to one of the pair of separated antennas and the combined signal amplitude level corresponding to another one of the pair of separated antennas.

4. The method of claim 2, wherein the noise is received at said each one of the pair of separated antennas;

and, wherein the step of determining includes using received noise levels for adjusting the combined signal amplitude levels.

5. The method of claim 2, wherein the step of determining includes aligning the pair of antennas to maximize the difference between the combined signal amplitude levels of the pair of antennas to estimate a direction to the transmitter.

6. The method of claim 4, further comprising the step of estimating a distance to the transmitter from the receiver from the difference in the combined signal amplitude levels.

7. The method of claim 1, wherein the step of transmitting uses three orthogonally polarized signals.

8. The method of claim 6, wherein the step of transmitting uses three magnetic dipole antennas or three electrical dipole antennas.

9. The method of claim 1, wherein the step of transmitting includes varying the distinctive signals by different frequencies, by time division multiplexing or by code division multiplexing.

10. The method of claim 9, wherein the step of varying the distinctive signals includes sufficient distinction to enable differentiation between a plurality of transmitters in the step of receiving.

11. The method of claim 1, wherein the step of receiving uses gain control circuits for receiving the transmitted signals.

12. The method of claim 11, wherein the step of determining uses algorithmic compensation for processing near-field portions of the transmitted signals.

13. The method of claim 1, wherein the step of transmitting is activated by a predetermined period of non-movement of the transmitter.

14. The method of claim 1 wherein the transmitter is located with respect to an object to be located and where the receiver is located with respect to the user.

15. The method of claim 14 wherein the object is a firefighter.

16. A system for determining the location of a transmitter using a receiver, comprising:

a transmitter adapted for orthogonally transmitting at least three distinctive signals;

the at least three distinctive signals having a frequency of most 200 kHz;

a receiver having a pair of separated antennas for receiving, in a near field region, the at least three orthogonally distinctive transmitted signals;

each one of the pair of separated antennas being located at separate ends of a linear structure;

the linear structure being configured to be handheld;

separate demodulators in the receiver for each one of the pair of separated antennas for demodulating the at least three distinctive signals received at said each one of the pair of separated antennas;

first signal processing circuitry in the receiver adapted for obtaining a transmitting antenna orientation invariant signal corresponding to said each one of the pair of separated antennas; and

second signal processing circuitry in the receiver adapted for using the transmitting antenna orientation invariant signals corresponding to said each one of the pair of separated antennas for determining a direction to the transmitter and providing indicator signal indicating proximity and distance to the transmitter;

whereby the system enables rescue of a first responder in almost any type of building including fully metallic buildings.

17. The system of claim 16, wherein the first signal processing circuitry is adapted to combine signal amplitude levels of the separate demodulated signals received for each respective antenna.

18. The system of claim 17, further comprising an indicator adapted to show a user of the receiver the relative difference between combined signal amplitude levels between the pair of separated antennas.

19. The system of claim 17, wherein the signal processing circuitry is adapted to use received noise levels for adjusting the combined signal amplitude levels.

20. The system of claim 17, wherein the pair of separated receiving antennas may be oriented with respect to each other to maximize the difference between the combined signal amplitude levels of the pair of separated antennas to estimate a direction to the transmitter.

21. The system of claim 17, wherein the second signal processing circuitry is adapted to estimate a distance to the transmitter from the receiver from a maximized difference in the combined signal amplitude levels.

22. The system of claim 16, wherein the pair of separated receiving antennas are mounted to a single instrument to enable easy directional reorientation.

23. The system of claim 16, wherein the pair of antennas is mounted to the receiver using at least one extendable member to provide separation between the pair of antennas during use and for compacting the receiver between uses.

24. The system of claim 16, wherein the transmitter includes three orthogonally oriented antennas for transmitting three orthogonal signals.

25. The system of claim 16, wherein the three transmitting antennas are three magnetic dipole antennas or three electrical dipole antennas.

26. The system of claim 16, wherein the three orthogonally oriented antennas are three coils wound around a cube form, orthogonally to each other.

27. The system of claim 16, wherein the transmitter is adapted to create the distinctive signals by using either different frequencies, time division multiplexing or code division multiplexing.

28. The system of claim 27, wherein the distinctive signals are sufficient to enable distinction there between and between a plurality of transmitters at the receiver.

29. The system of claim 16, wherein the receiver includes gain control circuits for receiving near-field portion of the transmitted signals.

30. The system of claim 29, wherein the first signal processing circuitry includes algorithmic compensation for processing the near-field portion of the transmitted signals.

31. The system of claim 16 wherein the transmitter is located with respect to an object to be located and where the receiver is located with respect to the user.

32. The system of claim 31 wherein the object is a firefighter.