Single receiver wireless tracking system

• US 6,590,535 B1
• Filed: 07/18/2000
• Issued: 07/08/2003
• 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:
  US09/618,480
• Time in Patent Office: 1,085 Days
• Field of Search: 342/457, 342/450
• US Class Current: 342/450
• 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 method for locating a target comprising the steps of:

configuring a directional antenna for receipt of a data stream transmitted over a communications path;

receiving the data stream with the configured directional antenna, the received data stream including a data field providing an indication of a propagation delay of the target, the propagation delay indication being determined by a datum in the data field;

determining a transmission interval and a transmission angle of the received data stream, the transmission interval being determined in accordance with the propagation delay indication; and

determining a position of the target from the determined transmission interval and the determined transmission angle.

2. The method according to claim 1, wherein the transmission interval determining step comprises the steps of transmitting to the target a data key uniquely associated with the target, receiving from the target the data field in response to the data key, and determining the transmission interval in accordance with the propagation delay, a transmit time of the data key, and a receipt time of the data field.

3. The method according to claim 2, wherein the step of target data key transmitting includes the step of direct sequence spreading encoding of the data key, and the step of data field receiving includes the step of direct sequence spreading decoding of the data field.

4. The method according to claim 2, wherein the directional antenna includes a plurality of antenna sectors, and the transmission angle determining step comprises the steps of measuring a signal amplitude and a signal phase of the data stream at a plurality of the antenna sectors, and determining the transmission angle from the respective signal amplitude and signal phase at adjacent ones of the antenna sectors.

5. The method according to claim 4, wherein each antennae sector defines an antennae lobe, each said lobe having a size and a shape, and the configuring step comprises dynamically varying at least one of the size and the shape of at least one of the lobes for obtaining a desired tracking resolution.

6. The method according to claim 5, wherein the transmission angle determining step comprises the steps of measuring a signal amplitude and a signal phase of the data field at a plurality of the antenna sectors, and the position determining step comprises filtering multi-path distortions in accordance with the measured amplitude and the measured phase.

7. The method according to claim 6, wherein the configuring step comprises measuring ambient noise adjacent to the directional antenna, and the position determining step further comprises determining the position with reference to the measured ambient noise.

8. A method for locating a target comprising the steps of:

configuring a directional antenna for receipt of a data stream transmitted over a communications path;

receiving the data stream with the configured directional antenna, the received data stream including a pulse providing an indication of a propagation delay of the target, the propagation delay indication being determined by a pulse width of the propagation delay pulse;

determining a transmission interval and a transmission angle of the received data stream, the transmission interval being determined in accordance with the propagation delay indication; and

determining a position of the target from the determined transmission interval and the determined transmission angle.

9. The method according to claim 8, wherein the transmission interval determining step comprises the steps of transmitting to the target a data key uniquely associated with the target, receiving from the target the pulse identifying the propagation delay of the target, and determining the transmission interval in accordance with a pulse width of the propagation delay pulse.

10. The method according to claim 8, wherein the directional antenna includes a plurality of antenna sectors, and the transmission angle determining step comprises the steps of measuring a signal amplitude and a signal phase of the data stream at a plurality of the antenna sectors, and determining the transmission angle from the respective signal amplitude and signal phase at adjacent ones of the antenna sectors.

11. The method according to claim 10, wherein each antennae sector defines an antennae lobe, each said lobe having a size and a shape, and the configuring step comprises dynamically varying at least lone of the size and the shape of at least one of the lobes for obtaining a desired tracking resolution.

12. The method according to claim 11, wherein the transmission angle determining step comprises the steps of measuring a signal amplitude and a signal phase of the data field at a plurality of the antenna sectors, and the position determining step comprises filtering multi-path distortions in accordance with the measured amplitude and the measured phase.

13. The method according to claim 12, wherein the configuring step comprises measuring ambient noise adjacent to the directional antennae, and the position determining step further comprises determining the position with reference to the measured ambient noise.

14. A method for locating a target comprising the steps of:

configuring a directional antenna for receipt of a data stream transmitted over a communications path;

determining a transmission interval and a transmission angle of the data stream, the transmission interval determining step comprising the steps of transmitting a first periodic signal to the target, receiving the data stream in response, the received data stream including a response periodic signal comprising a retransmission of the first periodic signal from the target, the response periodic signal providing an indication of a propagation delay of the target, and determining the transmission interval in accordance with a phase difference between the periodic signals; and

determining a position of the target from the determined transmission interval and the determined transmission angle.

15. The method according to claim 14, wherein the directional antenna includes a plurality of antenna sectors, and the transmission angle determining step comprises the steps of measuring a signal amplitude and a signal phase of the data stream at a plurality of the antenna sectors, and determining the transmission angle from the respective signal amplitude and signal phase at adjacent ones of the antenna sectors.

16. The method according to claim 15, wherein each antennae sector defines an antennae lobe, each said lobe having a size and a shape, and the configuring step comprises dynamically varying at least one of the size and the shape of at least one of the lobes for obtaining a desired tracking resolution.

17. The method according to claim 16, wherein the transmission angle determining step comprises the steps of measuring a signal amplitude and a signal phase of the data field at a plurality of the antenna sectors, and the position determining step comprises filtering multi-path distortions in accordance with the measured amplitude and the measured phase.

18. The method according to claim 17, wherein the configuring step comprises measuring ambient noise adjacent to the directional antennae, and the position determining step further comprises determining the position with reference to the measured ambient noise.