Tracking and position determination system

• US 4,060,809 A
• Filed: 04/09/1975
• Issued: 11/29/1977
• Est. Priority Date: 04/09/1975
• Status: Expired due to Term

• Current Assignee: Elie J. Baghdady
• Original Assignee: Elie J. Baghdady
• Inventors: Baghdady, Elie J.
• Primary Examiner(s): Tubbesing, T.H.
• Assistant Examiner(s): Berger, Richard E.
• Application Number:
  US05/566,195
• Time in Patent Office: 965 Days
• Field of Search: 343/113 DE, 343/106 D, 343/112 R, 343/108 M
• US Class Current: 342/451
• CPC Class Codes: G01S 1/40 the apparent movement of the antenna being produced by cyclic sequential energisation of fixed antennas
• CPC Class Codes: G01S 5/0246 involving frequency difference of arrival or Doppler measurements G01S5/02685 takes precedence
• CPC Class Codes: G01S 5/0249 Determining position using measurements made by a non-stationary device other than the device whose position is being determined

Abstract

A method and apparatus for tracking and position determination includes generating carrier waves in transmitters; radiating said carrier waves; receiving said radiated carrier waves; imparting or simulating a motion, or motions, to radiators, reflectors or/and receiving antennas, within the locality of each, in such a way as to induce direction-dependent frequency modulation in each signal delivered to the receiving detectors; detecting said modulation on each received signal; and using measured parameters of said detected modulation to track the location of one or more of the said transmitters, reflectors or/and receivers and determine the corresponding position coordinates thereof. The actual or simulated motion of the radiators reflectors or antennas may have a uniform velocity along at least two straight, non-parallel lines.

Claims

1. A method of determining position coordinates of an object relative to a reference coordinate system, comprising the steps of:

radiating carrier waves from a radiating position at one of said object and a station having a known location in said reference coordinate system;

receiving the carrier waves at a receiving position at the other of said object and said station;

varying the location of at least one of said radiating and said receiving positions in a first predetermined manner and a second predetermined manner, different from the first;

measuring the frequency of the received carrier waves when the location of the one of said radiating and receiving positions is varied in the first predetermined manner;

measuring the frequency of the received carrier waves when the location of the one of said radiating and receiving positions is varied in the second predetermined manner; and

determining a position coordinate of the object responsive to a difference between the measured frequencies of the received carrier waves.

2. The method of claim 1 wherein the varying of the location of at least one of said radiating and said receiving positions is effected repetitively and wherein said predetermined paths are two non-parallel paths.

3. The method of claim 1 wherein:

the carrier waves are transmitted by a transmitter;

the carrier waves are radiated by reflection from the object; and

,

the reflected carrier waves are received by at least one antenna, having a known location on the coordinate system, at at least one receiving position on the antenna, the location of which position is repetitively varied along the predetermined paths.

4. The method of claim 1 wherein:

the carrier waves are transmitted by a transmitter;

the carrier waves are received by the object and retransmitted; and

,

the retransmitted carrier waves are received by at least one antenna, having a known location on the coordinate system, at at least one receiving position on the antenna, the location of which position is repetitively varied along the predetermined paths.

5. The method of claim 1 wherein:

the carrier waves are radiated from the object by a transmitter on the object; and

,

the radiated carrier waves are received by an antenna, having a known location on the coordinate system, at at least one receiving position on the antenna, the location of which receiving position is repetitively varied along the predetermined paths.

6. The method of claim 1 wherein:

the carrier waves are radiated by a transmitter, having a known location on the coordinate system; and

,

the radiated carrier waves are received by the object, at at least one receiving position, the location of which receiving position is repetitively varied along the predetermined paths.

7. The method of claim 6 wherein the carrier waves are radiated by a plurality of transmitters, each having a known location in the coordinate system.

8. The method of claim 1 wherein:

the carrier waves are radiated by reflection from the object at at least one radiating position on the object; and

,

the carrier waves are received by an antenna, said antenna having a known location on the coordinate system; and

,

wherein the location of at least one of the radiating positions is repetitively varied along the predetermined paths.

9. The method of claim 1 wherein:

the carrier waves are radiated by a transmitter, having a known location on the coordinate system, from at least one radiating position the location of which is repetitively varied along the predetermined paths.

10. The method of claim 1 wherein the position coordinates of the object which are determined are the elevational angle and azimuthal angle.

11. The method of claim 1 wherein the location of at least one of said radiating and said receiving positions is varied by reciprocating motion at a generally uniform speed along non-parallel straight lines.

32. The method of claim 1 wherein the location of the radiating position is varied and further comprising the steps of:

radiating carrier waves from another radiating position at the one of said object and said station; and

varying the location of said another radiating position in a first predetermined manner and a second predetermined manner, different from the first, thereby inducing two different Doppler frequency shifts in the carrier waves, the location of said another radiating position being varied along a path non-parallel to a path along which the other radiating position is varied; and

,

wherein position coordinates of the object are determined responsive to the frequency of the carrier waves received from both radiating positions.

33. The method of claim 32 wherein the position coordinates of the object are determined by:

determining a first difference between the frequency of the carrier waves received from said another radiating position when the location is varied in the first predetermined manner and the frequency when the location is varied in the second predetermined manner;

determining a first difference between the frequency of the carrier waves received from said another radiating position when the location is varied in the first predetermined manner and the frequency when the location is varied in the other predetermined manner; and

,

determining position coordinates of the object responsive to said determined differences.

34. The method of claim 1 wherein the location of the receiving position is varied and further comprising the steps of:

receiving carrier waves at another receiving position at the one of said object and said station; and

varying the location of said another receiving position in a first predetermined manner and a second predetermined manner, different from the first, thereby inducing two different Doppler frequency shifts in the carrier waves, the location of said another receiving position being varied along a path at least partially non-parallel to a path along which the other receiving position is varied; and

,

wherein position coordinates of the object are determined responsive to the frequency of the carrier waves received at both receiving positions.

35. The method of claim 34 wherein the position coordinates of the object are determined by:

determining a first difference between the frequency of the carrier waves received at said another receiving position when the location is varied in the first predetermined manner and the frequency when the location is varied in the second predetermined manner;

determing a first difference between the frequency of the carrier waves received at said another receiving position when the location is varied in the first predetermined manner and the frequency when the location is varied in the other predetermined manner; and

,

determining position coordinates of the object responsive to said determined differences.

36. The method of claim 1 wherein the location of the one of said radiating and receiving positions is varied in the first and second predetermined manners by repetitively moving the position back and forth along a straight line.

37. The method of claim 36 wherein the position coordinate of the object is determined by averaging the frequencies of the received carrier waves to determine the unshifted frequency of the carrier waves;

calculating upward and downward shifts in the frequency of the carrier waves from the unshifted frequency of the carrier waves due to the varying of the location of the one of said radiating and receiving positions; and

calculating the position coordinate of the object responsive to the calculated upward and downward shifts in the frequency of the carrier waves.

38. The method of claim 37 wherein the position coordinate of the object is determined responsive to the ratio of the calculated upward and downward shifts in the frequency of the carrier waves.

39. The method of claim 1 wherein the location of the one of said radiating and receiving positions is varied in the first and second predetermined manners by moving the position at two different speeds along a straight line.

12. An apparatus for determining the location of a station in a reference coordinate system comprising:

at least two antenna means in the locality of the station, for receiving the carrier waves, each antenna means having at least one carrier wave receiving position which moves repetitively with a uniform speed so that carrier waves are received along at least two non-parallel lines;

means for radiating carrier waves to said receiving antenna means from a known location in the reference coordinate system; and

,

means, communicating with said antenna means, for determining the location of the station with respect to the reference coordinate system responsive to frequency modulations of the carrier waves induced by the movements of the receiving positions.

13. An apparatus for determining position coordinates of an object comprising:

first means for radiating carrier waves from a radiating position;

antenna means for receiving carrier waves from the object at a receiving position of the antenna means;

means for varying the location of one of said radiating and receiving positions in a first predetermined manner and a second predetermined manner, different from the first, thereby inducing two different Doppler frequency shifts in the carrier waves; and

,

means for determining position coordinates of the object responsive to a difference between the frequency of the received carrier waves when the location is varied in the first predetermined manner and the frequency when the location is varied in the second predetermined manner.

14. The apparatus of claim 13 further comprising:

a second radiating means, spaced a known distance from the first radiating means, for radiating carrier waves from an additional radiating position; and

,

wherein said varying means periodically varies the locations of the radiating positions of said first and said second radiating means along at least two predetermined non-parallel paths.

15. The apparatus of claim 14 wherein the locations of said radiating positions are each varied by repetitive motion and wherein the paths are at least two non-parallel straight lines.

16. The apparatus of claim 15 wherein the paths are three straight lines not all lying in the same plane.

17. The apparatus of claim 13 wherein said radiating means is located on said object and the radiating position moves on the object with a uniform velocity;

wherein said antenna means includes at least three spatially separated, non-colinearly positioned antennas; and

,

wherein said determining means determines the orientation, with respect to the reference coordinate system of the antenna means, an axis of the object generally parallel to a direction of movement of the said radiating position of said radiating means with respect to the object.

18. The apparatus of claim 13 further comprising means for directing the carrier waves around an obstruction lying between said radiating means and said antenna means.

19. The apparatus of claim 13 wherein the object is a projectile and the radiating means and antenna means are located on a target.

20. The apparatus of claim 19 wherein said apparatus further comprises radar means on said target for determining the distance between the projectile and the target.

21. The apparatus of claim 19 further comprising a second radiating means spaced on said target a known distance from said first radiating means, for radiating carrier waves from an additional radiating position.

40. The apparatus of claim 13 wherein said location varying means varies the location of the one of said radiating and receiving positions in the first and second predetermined manners by repetitively moving the position back and forth along a straight line.

22. An apparatus for determining position coordinates of an object comprising:

a first transmitter for transmitting first carrier waves from at least one position moving repetitively at a generally uniform speed along at least two non-parallel lines, whereby frequency modulation is induced by the Doppler effect in said transmitted first carrier waves;

a second transmitter, displaced a known distance from said first transmitter, for transmitting second carrier waves from at least one position moving repetitively at a generally uniform speed along at least two non-parallel lines, whereby frequency modulation is induced by the Doppler effect in said transmitted second carrier waves;

antenna means for receiving said first and second carrier waves directed by the object to said antenna means; and

,

means operatively connected to said antenna means for determining the position coordinates of the object with respect to said transmitters, responsive to the induced frequency modulation of the received first and second carrier waves.

23. The apparatus of claim 22 wherein said first and second transmitters each include a first radiating element moved along a first line of motion and a second radiating element moved along a second line of motion non-parallel to the first line of motion.

24. The apparatus of claim 22 wherein said first and second transmitters each include an arrangement of radiating elements, commutated to move the point of radiation of carrier waves along the two non-parallel lines.

25. The apparatus of claim 22 further comprising:

a third transmitter located at a known position with respect to said first and second transmitters, which transmits a signal directed by the object and received by said antenna means; and

,

means for determining the velocity vector of the object responsive to the induced frequency modulations of the received first and second carrier waves and the received signal from said third transmitter.

26. The apparatus of claim 22 wherein said first tranmitter transmits the first carrier wave from at least one position moving along three mutually non-parallel non-coplanar lines.

41. The apparatus of claim 23 wherein said location varying means varies the location of the one of said radiating and receiving positions in the first and second predetermined manners by moving the position at two different speeds along a straight line.

27. An apparatus for determining the position coordinates of an object comprising:

a first means for radiating carrier waves;

a first antenna means for receiving carrier waves directed by the object at at least one position on said first antenna means which position moves repetitively at a generally uniform speed along at least two non-parallel lines, whereby frequency modulation is induced in said received carrier waves;

a second antenna means, displaced a known distance from said first antenna means, for receiving carrier waves directed by the object at at least one position on said second antenna means which position moves repetitively at a generally uniform speed along at least two non-parallel lines, whereby frequency modulation is induced in said received carrier waves; and

,

means operatively connected to said first and second antenna means for determining the position coordinates of the object with respect to said antenna means, responsive to the induced frequency modulation of the received carrier waves.

28. The apparatus of claim 27 wherein said first and second antenna means each comprise a first antenna moved along a first line of motion and a second antenna moved along a second, non-parallel line of motion.

29. The apparatus of claim 27 wherein said first and second antenna means each comprise an arrangement of receiving elements, commutated to move the point of reception of the carrier waves along two non-parallel lines at a generally uniform speed.

30. The apparatus of claim 27 further comprising:

a third antenna means, located at a known position with respect to said first and second antenna means, for receiving the carrier waves directed by the object; and

means for determining the velocity vector of the object responsive to the induced frequency modulation of the carrier waves received by said first and said second antenna means and responsive to Doppler shift of the carrier wave received by said third antenna means.

31. The apparatus of claim 27 wherein said first antenna means receives the carrier wave at at least one position moving along three mutually non-parallel, non-coplanar straight lines.

42. A method of determining the position of an object relative to known reference location, comprising the steps of:

radiating carrier waves from along two at least partially non-parallel lines at one of the object and the known reference location by varying the location of at least one radiating position to induce Doppler shift in the carrier waves;

receiving the carrier waves at at least two antennae spaced apart at the other of the object and the known location;

sensing the Doppler shift of the carrier waves received at each of the antennae; and

,

calculating the position of the object from the sensed Doppler shifts, the separation of the two antennae and the coordinates of the known reference location.

43. An apparatus for determining position coordinates of an object comprising:

first means for radiating carrier waves from a radiating position;

antenna means for receiving carrier waves directed by the object to a receiving position;

means for varying in a predetermined manner the location of one of said radiating and receiving positions, thereby inducing at least two separate independent frequency modulations in the carrier waves each of which is dependent at least in a partially separate and independent manner on the position coordinates of the object;

means for separately determining each of the induced independent frequency modulations of the received carrier waves; and

,

means for determining position coordinates of the object responsive to the induced independent frequency modulations of the received carrier waves.