Multi-path mitigation in rangefinding and tracking objects using reduced attenuation RF technology

• US 7,969,311 B2
• Filed: 01/18/2011
• Issued: 06/28/2011
• Est. Priority Date: 12/15/2005
• Status: Active Grant

• Current Assignee: Qualcomm Technologies Incorporated (Qualcomm, Inc.)
• Original Assignee: InvisiTrack, Inc.
• Inventors: Markhovsky, Felix, Prevatt, Truman
• Primary Examiner(s): Bugg; George A
• Assistant Examiner(s): Labbees; Edny
• Application Number:
  US13/008,519
• Publication Number:
  US 20110111751A1
• Time in Patent Office: 161 Days
• Field of Search: 3405721-5729, 340/539.13, 340/825.49, 340/568.1, 340/541, 340/573.1, 342/47, 342/204, 702/158, 235375-385, 235/425, 235/560
• US Class Current: 340/572.1
• CPC Class Codes: G01S 13/767 Responders; Transponders teaching or practice apparatus for gun-aiming or gun-laying using reflecting targets or active targets F41G3/26
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G01S 2013/466 by Trilateration, i.e. two antennas or two sensors determine separately the distance to a target, whereby with the knowledge of the baseline length, i.e. the distance between the antennas or sensors, the position data of the target is determined
• CPC Class Codes: G01S 2013/468 by Triangulation, i.e. two antennas or two sensors determine separately the bearing, direction or angle to a target, whereby with the knowledge of the baseline length, the position data of the target is determined
• CPC Class Codes: G01S 3/74 Multi-channel systems specially adapted for direction-finding, i.e. having a single antenna system capable of giving simultaneous indications of the directions of different signals systems in which the directions of different signals are determined sequentially and displayed simultaneously G01S3/04, G01S3/14
• CPC Class Codes: G01S 5/0205 Details
• CPC Class Codes: G01S 5/0218 Multipath in signal reception
• CPC Class Codes: G01S 5/0273 using multipath or indirect path propagation signals in position determination
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location

Abstract

A method and system for identification, tracking and locating in wireless communications and wireless networks. The method and system use reference and/or pilot signals that are present in wireless communications and wireless networks. The method and system might also use RTT, TOA and time-stamping measurements/techniques to determine one or more reference signals traveling time between the Base Station (eNB) or its functional equivalent and mobile device (UE) and or network device. Other wireless networks that do not use reference and/or pilot signals may employ one or more of the following types of alternate embodiments of present invention: 1) where a portion of frame is dedicated to the ranging signal/ranging signal elements; 2) where the ranging signal elements are embedded into (spread across) transmit/receive signals frame(s); and 3) where the ranging signal elements are embedded with the data. The method and system includes multi-path mitigations processor and multi-path mitigations techniques and algorithms which improve the track-locate accuracy. The method and system allow achieving increased accuracy by using multi-path mitigations processor and multi-path mitigations techniques and algorithms. The techniques of Digital Signal Processing and Software-Defined Radio are used.

Claims

1. A system for tracking and locating wireless network devices, the system comprising:

a multipath mitigation processor configured to receive and process reference signals of the wireless network;

the multipath mitigation processor using the reference signals to measure a distance between the wireless network devices;

wherein a high-resolution spectrum estimation analysis is used to reduce spatial ambiguity in the distance measurement, including estimating a model size for a number of frequency components, and calculating the distance based on a distribution of the frequency components;

wherein the system employs noise reduction methods that include any of coherent summing, non-coherent summing, matched filtering and temporal diversity; and

wherein a remainder of the multi-path interference error is further reduced by applying the post-processing techniques, including any of maximum likelihood estimation (Viterbi Algorithm) and minimal variance estimation (Kalman Filter).

2. The system of claim 1, wherein the multipath mitigation processor is configured to receive RTT (Round Trip Time) measurement(s) from a wireless network device to compute an actual (absolute) phase value or phase and amplitude values of the reference signals of the wireless network.

3. The system of claim 1, wherein the multipath mitigation processor is configured to receive TOA (Time of Arrival) measurements and to compute phase and amplitude values of the reference signals of the wireless network.

4. The system of claim 1, wherein the multipath mitigation processor is configured to receive DTOA (Differential Time of Arrival) and to compute an actual (absolute) phase value of the reference signals of the wireless network.

5. The system of claim 1, wherein the multipath mitigation processor time-stamps and processes the reference signals so as to compute an actual (absolute) phase value or phase and amplitude values of the reference signals of the wireless network, for determining the distance.

6. The system of claim 1, wherein the multipath mitigation processor uses a channel estimation (response determination) computed by the wireless network devices, for determining the distance.

7. The system of claim 1, wherein the wireless receiver is configured to receive narrow bandwidth signals.

8. The system of claim 1, wherein the multipath mitigation processor supports half-duplex, full duplex or simplex mode of operation.

9. The system of claim 1, wherein the multipath mitigation processor uses any of the following methods to estimate the distance and track-locate:

Time of Arrival (TOA);

Differential Time of Arrival (DTOA);

a combination of TOA and DTOA;

Triangulation and/or Trilateration;

Virtual triangulation and Reverse Virtual Triangulation;

OTDOA (Observed Time Difference of Arrival), including DL-OTDOA (Downlink OTDOA);

Enhanced Cell ID;

CELL ID+RTT;

Cell ID+AOA (Angle of Arrival); and

Cell ID+AOA (Angle of Arrival)+RTT.

10. A method for tracking and locating wireless network devices, the method comprising:

configuring a multipath mitigation processor to receive and process a ranging signal of the wireless network;

configuring a multipath mitigation processor to generate and transmit a ranging signal of the wireless network;

using the ranging signal and the processor to measure a distance between the wireless network devices; and

wherein a high-resolution spectrum estimation analysis is used to reduce spatial ambiguity in the distance measurement, including estimating a model size for a number of frequency components, and calculating the distance based on a distribution of the frequency components; and

wherein the system employs noise reduction methods that include any of coherent summing, non-coherent summing, matched filtering and temporal diversity; and

wherein a remainder of the multi-path interference error is further reduced by applying the post-processing techniques, including any of maximum likelihood estimation (Viterbi Algorithm) and minimal variance estimation (Kalman Filter).

11. The method of claim 10, wherein a portion of a transmit/receive wireless network frame is dedicated to ranging signal components.

12. The method of claim 10, wherein the ranging signal components are spread across (embedded) the transmit/receive frame.

13. The method of claim 10, wherein the ranging signal components are embedded with the transmit/receive data.

14. The method of claim 10, wherein the ranging signal is a wide bandwidth signal and the signal comprises of different individual narrow bandwidth frequency components.

15. The method of claim 10, wherein the ranging signal is a narrow bandwidth signal, and the system uses different individual narrow bandwidth frequency components to generate the narrow bandwidth ranging signal and a base-band narrow bandwidth ranging signal.

16. The method of claim 10, wherein different narrow bandwidth frequency components of the ranging signal and a base-band ranging signal are pseudorandomly selected, the components are contiguous and spaced apart in frequency.

17. The method of claim 10, wherein the reference signal is a pilot signal.

18. A system for tracking and locating wireless network devices, the system comprising:

a multipath mitigation processor configured to receive and process a pilot signal of the wireless network; and

means for using the pilot signal and the processor to measure a distance between the wireless network devices by utilizing a high-resolution spectrum estimation analysis to reduce spatial ambiguity in the distance measurement, including estimating a model size for a number of frequency components, and calculating the distance based on a distribution of the frequency components; and

wherein the system employs noise reduction methods that include any of coherent summing, non-coherent summing, matched filtering and temporal diversity; and

wherein a remainder of the multi-path interference error is further reduced by applying the post-processing techniques, including any of maximum likelihood estimation (Viterbi Algorithm) and minimal variance estimation (Kalman Filter).

19. The system of claim 18, wherein the reference signal is a pilot signal.

20. The system of claim 18, further comprising a wireless receiver configured to receive a narrow bandwidth signal as the pilot signal.

21. The system of claim 18, wherein the multipath mitigation processor supports half-duplex, full duplex or simplex mode of operation.

22. The system of claim 18, wherein the multipath mitigation processor uses any of the following methods to estimate the distance and track-locate:

Time of Arrival (TOA);

Differential Time of Arrival (DTOA);

a combination of TOA and DTOA;

Triangulation and/or Trilateration;

Virtual triangulation and Reverse Virtual Triangulation;

OTDOA (Observed Time Difference of Arrival), including DL-OTDOA (Downlink OTDOA);

Enhanced Cell ID;

CELL ID+RTT;

Cell ID+AOA (Angle of Arrival); and

Cell ID+AOA (Angle of Arrival)+RTT.

23. A system for tracking and locating wireless network devices, comprising:

a wireless receiver adapted to interface to wireless network devices to measure the Angle of Arrival (AOA) from a network device;

wherein the wireless receiver is configured to receive signals from wireless network devices;

wherein the wireless receiver is configured to interface to a multipath mitigation processor;

wherein the received signals are used for measuring the AOA from a wireless network c device, and

the multipath mitigation processor configured and process the received signals;

wherein a high-resolution spectrum estimation analysis is used to reduce spatial ambiguity in the distance measurement, including estimating a model size for a number of multi-path frequency components, and calculating the distance based on a distribution of the frequency components; and

wherein the system employs noise reduction methods that include any of coherent summing, non-coherent summing, matched filtering and temporal diversity; and

wherein the system further reduces a remainder of the multi-path interference error by applying the post-processing techniques, including any of maximum likelihood estimation (Viterbi Algorithm) and minimal variance estimation (like Kalman Filter).

24. The system of claim 23, wherein the multipath mitigation processor uses any of the following methods to estimate the distance and track-locate:

Time of Arrival (TOA);

Differential Time of Arrival (DTOA);

a combination of TOA and DTOA;

Triangulation and/or Trilateration;

Virtual triangulation and Reverse Virtual Triangulation;

OTDOA (Observed Time Difference of Arrival), including DL-OTDOA (Downlink OTDOA);

Enhanced Cell ID;

CELL ID+RTT;

Cell ID+AOA (Angle of Arrival); and

Cell ID+AOA (Angle of Arrival)+RTT.