Single receiver wireless tracking system

• US 6,437,740 B1
• Filed: 07/18/2000
• Issued: 08/20/2002
• Est. Priority Date: 04/27/1999
• Status: Expired due to Term

• Current Assignee: Stelx Incorporated
• Original Assignee: Stelx Incorporated
• Inventors: Gerlach, Frank, De Champlain, Brian
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US09/618,483
• Time in Patent Office: 763 Days
• Field of Search: 342/417, 342/422, 342/423, 342/153, 455/73, 455/456
• US Class Current: 342/417
• CPC Class Codes: G01S 13/4418 with means for eliminating radar-dependent errors in angle measurements, e.g. multipath effects
• CPC Class Codes: G01S 13/765 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 13/825 with exchange of information between interrogator and responder
• CPC Class Codes: G01S 7/292 Extracting wanted echo-signals
• CPC Class Codes: G01S 7/4004 of parts of a radar system
• CPC Class Codes: H01Q 1/125 Means for positioning
• CPC Class Codes: H01Q 1/22 by structural association with other equipment or articles
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 19/28 using a secondary device in the form of two or more substantially straight conductive elements log- periodic antennas H01Q11/10; constituting a reflecting surface H01Q19/10
• CPC Class Codes: H01Q 21/067 using endfire radiating aerial units transverse to the plane of the array
• CPC Class Codes: H01Q 21/10 Collinear arrangements of substantially straight elongated conductive units
• CPC Class Codes: H01Q 21/12 Parallel arrangements of substantially straight elongated conductive units travelling-wave antennas comprising transmission line loaded with transverse elements H01Q11/02; Yagi antennas H01Q19/30
• 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 21/245 provided with means for varying the polarisation polarising devices H01Q15/24; tracking by comparing linear polarisation compounds G01S3/146; reducing depolarisation effects H04B7/00; polarisation diversity H04B7/10
• CPC Class Codes: H01Q 21/29 Combinations of different interacting antenna units for giving a desired directional characteristic H01Q25/00 takes precedence
• CPC Class Codes: H01Q 25/00 Antennas or antenna systems providing at least two radiating patterns arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00
• CPC Class Codes: H01R 13/6273 comprising two latching arms

Abstract

A wireless tracking system consists of a wireless target including a wireless communication system for transmitting a data packet over a communication path, and a locating station for determining a position of the target. The data packet transmitted from the target includes an identification code uniquely associated with the target. The locating station includes a configurable directional antenna, a communication interval processing system, a direction processing system, and a position processing system. The communication interval processing system is in communication with the directional antenna and determines the transmission interval of the transmitted data packet over the communication path. The direction processing system determines the transmission angle of the communication path, and is in communication with the directional antenna for controlling the configuration of the directional antenna so as to facilitate the determination of the transmission angle. The position processing system is in communication with the interval processing system and the direction processing system, and determines the target position from the identification code, the transmission interval and the transmission angle.

Claims

1. A wireless locating station for determining a position of a target, the locating station comprising:

a configurable directional antenna for receiving over a communication path a data packet from the target, the data packet including an identification code uniquely associated with the target;

a communication interval processing system in communication with the directional antenna for determining a transmission interval of the transmitted data packet over the communication path;

a direction processing system for determining a transmission angle of the communication path, the direction processing system being in communication with the directional antenna for controlling a configuration of the antenna array for facilitating the transmission angle determining; and

a position processing system in communication with the interval processing system and the direction processing system for determining the target position from the identification code, the transmission interval and the transmission angle.

2. The wireless locating station according to claim 1, wherein the direction processing system comprises a phase detector for determining a phase of the received data packet relative to a system clock, and an amplitude detector for determining an amplitude of the received data packet, and the position processing system includes a signal processing system in communication with the phase detector and the amplitude detector for deriving the transmission angle from at least one of the phase and the amplitude.

3. The wireless locating station according to claim 2, wherein the directional antenna includes a plurality of antenna sectors each defining an antenna lobe, each said lobe having a size and a shape, and the position processing system further comprises an antenna controller in communication with the signal processing system for varying at least one of the size and the shape of at least one of the lobes for obtaining a desired tracking resolution.

4. The wireless locating station according to claim 2, wherein the position processing system is configured for facilitating direct sequence spreading communication with the target.

5. The wireless locating station according to claim 2, wherein the signal processing system includes a signal processor for filtering multi-path distortions.

6. The wireless locating station according to claim 2, wherein the signal processing system comprises an ambient noise database identifying ambient noise surrounding the directional antenna, and a signal processor in communication with the ambient noise database for determining the position with reference to the ambient noise.

7. The wireless locating station according to claim 1, further comprising a data transmitter for transmitting to the target a data key uniquely associated with the target, and a data receiver for receiving from the target the data packet in response to the data key and for receiving an indication of a propagation delay through the target, and the communication interval processing system comprises an interval counter in communication with the data transmitter and the data receiver for determining the transmission interval in accordance with the propagation delay indication, a transmit time of the data key, and a receipt time of the data packet.

8. The wireless locating station according to claim 7, wherein the propagation delay indication is provided as a data field of the data packet, and the interval counter is configured for determining the transmission interval in accordance with the propagation delay data field.

9. The wireless locating station according to claim 7, wherein the propagation delay indication is provided as a pulse transmitted from the target, and the interval counter is configured for determining the transmission interval in accordance with a pulse width of the propagation delay pulse.

10. The wireless locating station according to claim 7, wherein the directional antenna comprises a plurality of antenna sectors, at least one of the antenna sectors being configured for transmitting the data key, at least one of the antenna sectors being configured for receiving the data packet.

11. The wireless locating station according to claim 1, wherein the directional antenna includes a centre antenna element in communication with the communication interval processing system and the direction processing system, a plurality of second antenna elements disposed about the centre antenna element, each said second antenna element together with the centre antenna element defining an antenna sector, and a switch matrix coupled to each said antenna sector for altering a configuration of each said antenna sector.

12. The wireless locating station according to claim 11, wherein the directional antenna further comprises a ground plane in proximity to and electrically isolated from the antenna elements, and the switch matrix comprises a plurality of first electronic switches for selectively grounding selected ones of the second antenna elements.

13. The wireless locating station according to claim 12, wherein a first portion of the second antenna elements is disposed at an inner radius about the centre antenna element, a second portion of the second antenna elements is disposed at an outer radius about the centre antenna element, each said antenna sector comprises one of the radially inner second antenna elements, one of the radially outer second antenna elements, and a conductor extending between the one radially inner second antenna element and the one radially outer second antenna element, and the switch matrix comprises a plurality of second electronic switches for selectively connecting together the second antenna elements of one of the antenna sectors with an associated one of the conductors.

14. The wireless locating station according to claim 13, wherein each said antenna sector includes a ground radiator disposed radially outwards from the associated second antenna elements, and the switch matrix comprises a plurality of third electronic switches for selectively grounding a radially innermost end of a selected one of the ground radiators.

15. The wireless locating station according to claim 14, wherein each said ground radiator comprises a plurality of ground radials, each said ground radial having a respective incline angle, each said third electronic switch being associated with a respective one of the ground radials for altering a radiation angle of the directional antenna.

16. A wireless locating station for determining a position of a target, the locating station comprising:

a configurable directional monopole antenna array for receiving over a communication path a data packet from the target, the data packet including an identification code uniquely associated with the target, the antenna array comprising a centre antenna element, a plurality of second antenna elements disposed about the centre antenna element, each said second antenna element together with the centre antenna element defining an antenna sector, and a switch matrix coupled to each said antenna sector for altering a configuration of each said antenna sector;

a communication interval processing system in communication with the centre antenna element for determining a transmission interval of the transmitted data packet over the communication path;

a direction processing system for determining a transmission angle of the communication path, the direction processing system being in communication with the antenna array for controlling a configuration of the antenna array for facilitating the transmission angle determining, the direction processing system including a phase detector in communication with the centre antenna element for determining a phase of the received data packet relative to a system clock, and an amplitude detector in communication with the centre antenna element for determining an amplitude of the received data packet; and

a position processing system in communication with the interval processing system and the direction processing system for determining the target position from the identification code, the transmission interval and the transmission angle, the position processing system including a signal processing system in communication with the phase detector and the amplitude detector for deriving the transmission angle from at least one of the phase and the amplitude, and an antenna controller in communication with the signal processing system for varying a configuration of at least one the antenna sectors for obtaining a desired tracking resolution.

17. The wireless locating station according to claim 16, further comprising a data transmitter for transmitting to the target a data key uniquely associated with the target, and a data receiver for receiving from the target the data packet in response to the data key and for receiving an indication of a propagation delay through the target, and the communication interval processing system comprises an interval counter in communication with the data transmitter and the data receiver for determining the transmission interval in accordance with the propagation delay indication, a transmit time of the data key, and a receipt time of the data packet.

18. The wireless locating station according to claim 17, wherein each said antenna sector includes a ground radiator disposed radially outwards from the associated second antenna elements, and the switch matrix comprises aplurality of electronic switches for selectively grounding a radially innermost end of a selected one of the ground radiators for altering a radiation angle of the antenna array.