Close range fault tolerant noncontacting position sensor

• US 5,493,308 A
• Filed: 03/09/1994
• Issued: 02/20/1996
• Est. Priority Date: 06/12/1992
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Postal Technologies Inc (Opex Corporation)
• Original Assignee: Lockheed Idaho Technologies Company
• Inventors: Anderson, Allen A., Bingham, Dennis N.
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US08/209,662
• Time in Patent Office: 713 Days
• Field of Search: 342/442, 342/444, 342/445, 342/463, 342/465
• US Class Current: 342/442
• 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

A method and system for locating the three dimensional coordinates of a moving or stationary object in real time. The three dimensional coordinates of an object in half space or full space are determined based upon the time of arrival or phase of the wave front measured by a plurality of receiver elements and an established vector magnitudes proportional to the measured time of arrival or phase at each receiver element. The coordinates of the object are calculated by solving a matrix equation or a set of closed form algebraic equations.

Claims

1. A system for determining instantaneously, the half space three dimensional spatial coordinates of a moving or stationary emitter source, comprising:

(a) receiver means for receiving a radiated energy signal, said receiver means being comprised of a plurality of reception elements established in a planar configuration, each reception element being located at a known element position;

(b) converter means in communication with said receiving means for converting the energy signal received by each reception element into a magnitude signal proportional to the energy signal received by each reception element;

(c) position processing means in communication with said converter means for calculating in real time the half space three dimensional position of the emitter source based upon a closed form solution of a set of linear equations derived from a vector loop relationship established for each reception element, said vector loop relationship comprising the magnitude of vectors formed from the emitter source to each reception element, from each reception element to a wave front tangency point and from the wave front tangency point back to the emitter source.

2. The system of claim 1 wherein for each reception element, the magnitude signal is equivalent to ψ

_n λ

/2π

, where ψ

_n represents the phase of the energy signal measured at the each reception element and λ

represents the wavelength of the radiated energy signal.

3. The system of claim 1 wherein for each reception element, the magnitude signal is equivalent to Δ

t_n υ

, where Δ

t_n represents measured time difference of arrival of the radiated energy signal at each reception element with respect to a reference reception element and υ

represents the velocity of the radiated energy signal.

4. The system of claim 1 wherein the number of reception elements is at least four elements.

5. The system of claim 1 wherein the radiating energy signal is a propagating longitudinal wave front having a frequency of between 200 Hz and 20 kHz.

6. The system of claim 1 wherein the radiating energy signal is a transverse wave front having a frequency of between 27 MHz and 23 GHz.

7. The system of claim 1 wherein the radiated energy signal is an unmodulated energy wave.

8. The system of claim 1 wherein the radiated energy signal is a randomly modulated energy wave.

9. The system of claim 1 wherein the radiated energy signal is a pulsed electromagnetic signal.

10. The system of claim 1 wherein the real time half space three dimension position of the emitter source is calculated in step (c) by solving the matrix equation represented by ##EQU7## and the equation ##EQU8## where Sx, Sy and SZ represent the three dimensional position of the emitter source, R is the range between the emitter source and an established reception element, Ax, Bx, Cx, Ay, By, and Cy represent the x and y coordinates of the reception elements and a, b, and c represent the magnitude signals converted by said converting means.

11. The system of claim 10 wherein the closed form solution of matrix equation is solved to calculate the real time three dimensional position of the emitter source.

12. A system for determining instantaneously, the full space three dimensional spatial coordinates of a moving or stationary emitter source, comprising:

(a) receiver means for receiving a radiated energy signal, said receiver means being comprised of a plurality of reception elements, said reception elements being aligned in a non-planar configuration and located at a known element position;

(b) converter means in communication with said receiving means for converting the energy signal received by each reception element into a magnitude signal proportional to the energy signal received by each reception element;

(c) position processing means in communication with said converter means for calculating in real time the full space three dimensional position of the emitter source based upon solving a closed form solution of a set of linear equations derived from vector loop relationship established for each reception element, said vector loop relationship comprising the magnitude of vectors formed from the emitter source to each reception element, from each reception element to a wave front tangency point and from the wave front tangency point back to the emitter source.

13. The system of claim 12 wherein for each reception element, the magnitude signal is equivalent to ψ

_n λ

/2π

, where ψ

_n represents the phase of the energy signal measured at the each reception element and λ

represents the wavelength of the radiated energy signal.

14. The system of claim 12 wherein for each reception element, the magnitude signal is equivalent to Δ

t_n υ

, where Δ

t_n represents the measured time difference of arrival of the radiated energy signal at each reception element with respect to a reference reception element and υ

represents the velocity of the radiated energy signal.

15. The system of claim 12 wherein the real time three dimensional position of the emitter source is calculated in step (c) by solving the matrix equation represented by ##EQU9## where Sx, Sy and SZ represent the three dimensional position of the emitter source, R is the range between the emitter source and an established reference reception element, Ax, Bx, Cx, Dx, Ex, Ay, By, Cy, Dy, Ey, Az, Bz, Cz, Dz and Ez represent the x, y and z coordinates of the reception elements and a, b, c, d and e represent the magnitude signals converted by said converting means.

16. The system of claim 15 wherein the closed form solution of matrix equation is solved to calculate the real time three dimensional position of the emitter source in full space.

17. The system of claim 12 wherein the number of reception elements is at least five elements.

18. The system of claim 12 wherein the radiating energy signal is a propagating longitudinal wave front having a frequency of between 200 Hz and 20 kHz.

19. The system of claim 12 wherein the radiating energy signal is a transverse wave front having a frequency of between 27 MHz and 23 GHz.

20. A method for locating in real time, the half space three dimensional spatial coordinates of a moving or stationary object, the steps comprising:

(a) establishing a plurality of receiver elements in planar configuration, each element being spaced from an adjacent element by a fixed distance parameter;

(b) receiving a radiated energy signal by the plurality of receiver elements;

(c) calculating for each receiver element a magnitude signal proportional to the energy signal received by the receiver element;

(d) determining in real time the half space three dimensional position of the emitter source based upon a closed form solution of a set of linear equations derived from a vector loop relationship established for each reception element, said vector loop relationship comprising the magnitude of vectors formed from the emitter source to each reception element, from each reception element to a wave front tangency point and from the wave front tangency point and from the wave front tangency point back to the emitter source.

21. The method of claim 20 wherein for each receiver element, the magnitude signal is equivalent to ψ

_n λ

/2π

, where ψ

_n represents the phase of the energy signal received at the each reception element and λ

represents the wavelength of the radiated energy signal.

22. The method of claim 20 wherein for each receiver element, the magnitude signal is equivalent to Δ

t_n υ

, where Δ

t_n represents the measured time difference of arrival of the radiated energy signal at each receiver element with respect to a reference receiver element and υ

represents the velocity of the radiated energy signal.

23. The method of claim 20 wherein the number of receiver elements is at least four elements.

24. The method of claim 20 wherein the radiating energy signal is a propagating longitudinal wave front having a frequency of between 200 Hz and 20 kHz.

25. The method of claim 20 wherein the radiating energy signal is a transverse wave front having a frequency of between 27 MHz and 23 GHz.

26. The method of claim 20 wherein the radiated energy signal is an unmodulated energy wave.

27. The method of claim 20 wherein the radiated energy signal is a randomly modulated energy wave.

28. The method of claim 20 wherein the radiated energy signal is a pulsed electromagnetic signal.

29. The method of claim 20 wherein the real time, half space three dimension position of the emitter source is calculated in step (c) by solving the matrix equation represented by ##EQU10## and the equation ##EQU11## where Sx, Sy and SZ represent the three dimensional position of the emitter source, R is the range between the emitter source and an established reference receiver element, Ax, Bx, Cx, Ay, By, and Cy represent the x and y coordinates of the receiver elements and a, b, and c represent the magnitude signals calculated in step (c).

30. The method of claim 29 wherein the closed form solution of matrix equation is solved to calculate the real time three dimensional position of the emitter source.

31. A method for locating in real time, the full space three dimensional spatial coordinates of a moving or stationary object, the steps comprising:

(a) establishing an plurality of receiver elements in a non-planar configuration, each element being spaced from an adjacent element by a fixed distance parameter;

(b) receiving energy signals by the plurality of receiver elements;

(c) calculating a plurality of distance oriented signals, said distance oriented signals being proportional to the energy signals received by the receiver elements;

(d) determining in real time the full space three dimensional position of the emitter source based upon solving a closed form solution of a set of linear equations derived from vector loop relationship established for each reception element, said vector loop relationship comprising the magnitude of vectors formed from the emitter source to each reception element, from each reception element to a wave front tangency point and from the wave front tangency point back to the emitter source.

32. The method of claim 31 wherein for each receiver element, the magnitude signal is equivalent to ψ

_n λ

/2π

, where ψ

_n represents the phase of the energy signal measured at the each receiver element and λ

represents the wavelength of the radiated energy signal.

33. The method of claim 31 wherein for each receiver element, the magnitude signal is equivalent to Δ

t_n υ

, where Δ

t_n represents the measured time difference of arrival of the radiated energy signal at each receiver element with respect to a reference receiver element and υ

represents the velocity of the radiated energy signal.

34. The method of claim 31 wherein the number of receiver elements is at least five elements.

35. The method of claim 31 wherein the radiating energy signal is a propagating longitudinal wave front having a frequency of between 200 Hz and 20 kHz.

36. The method of claim 31 wherein the radiating energy signal is a transverse wave front having a frequency of between 27 MHz and 23 GHz.

37. The method of claim 31 wherein the radiated energy signal is an unmodulated energy wave.

38. The method of claim 31 wherein the radiated energy signal is a randomly modulated energy wave.

39. The method of claim 31 wherein the radiated energy signal is a pulsed electromagnetic signal.

40. The method of claim 39 wherein the real time three dimensional position of the emitter source is calculated in step (c) by solving the matrix equation represented by ##EQU12## where Sx, Sy and SZ represent the three dimensional position of the emitter source, R is the range between the emitter source and an established reference receiver element, Ax, Bx, Cx, Dx, Ex, Ay, By, Cy, Dy, Ey, Az, Bz, Cz, Dz and Ez represent the x, y and z coordinates of the receiver elements and a, b, c, d and e represent the magnitude signals calculated in step (c).

41. The method of claim 40 wherein the closed form solution of matrix equation is solved to calculate the real time three dimensional position of the emitter source.