Methods and apparatus to position a mobile receiver using downlink signals, part I

• US 6,208,297 B1
• Filed: 10/09/1998
• Issued: 03/27/2001
• Est. Priority Date: 10/09/1998
• Status: Expired due to Term

• Current Assignee: CELL-LOC LOCATION TECHNOLOGIES INC.
• Original Assignee: Cell-Loc Inc. (Pembina Pipeline Corp.)
• Inventors: Fattouche, Michel, Klukas, Richard
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Mull, Fred H.
• Application Number:
  US09/169,916
• Time in Patent Office: 900 Days
• Field of Search: 455/456, 455/422, 342/450, 342/457, 342/463, 342/464, 342/357.01, 342/357.02, 342/357.06, 375/350
• US Class Current: 342/450
• CPC Class Codes: G01S 2205/008 using a mobile telephone network
• CPC Class Codes: G01S 5/0009 Transmission of position information to remote stations involving assistance data G01S5/0236
• CPC Class Codes: G01S 5/0246 involving frequency difference of arrival or Doppler measurements G01S5/02685 takes precedence
• CPC Class Codes: G01S 5/08 Position of single direction-finder fixed by determining direction of a plurality of spaced sources of known location
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: G01S 5/12 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04B 7/18539 Arrangements for managing radio, resources, i.e. for establishing or releasing a connection
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

The invention comprises of methods and apparatus to estimate the position and velocity of a Mobile Receiver (MR) using either the Time Of Arrival (TOA) of signals received by the MR, their Phase Of Arrival (POA), their Strength Of Arrival (SOA), their Frequency Of Arrival (FOA), or a combination thereof, with respect to a reference produced by a Reference Receiver (RR) of known location. In order to solve for the coordinates of the MR, the invention uses either hyperbolic multilateration based on Time Difference Of Arrival (TDOA), or linear multiangulation based on Phase Difference Of Arrival (PDOA), or both. In order to solve for the velocity of the MR, the patent uses FOA based on Frequency Difference Of Arrival (FDOA). An important contribution of this invention is the way the MR receives, processes and combines available signals for location purposes. Another important contribution of this invention is the way the RR receives, processes and combines available signals for reference purposes. Yet another important contribution of the invention is the application of Super-Resolution (SR) techniques at both the MR and the RR to increase the resolution of the estimated TOAs, POAs, SOAs, or FOAs.

Claims

1. A method of estimating the location of a Mobile Receiver (MR) comprising the steps of:

receiving a plurality of signals from a plurality of Base Station Transmitters (BSTs) by the MR;

performing a nonlinear operation on the plurality of received signals at the MR in order to generate at least one tone for each received signal;

extracting the at least one tone from each received signal by performing a Fourier Transform (FT) on segments of the received signal, windowing desired frequency domain bands for each segment; and

performing an inverse Fourier Transform (IFT) on the windowed desired frequency domain bands; and

locating the Mobile Receiver using the extracted tones.

2. The method of claim 1 wherein the nonlinear operation is selected from the group consisting of:

a quadratic operation;

a delay product operation; and

an absolute value operation.

3. The method of claim 1 where locating the Mobile Receiver is performed by estimating the phases of the extracted tones.

4. The method of claim 1 wherein the received signals are filtered prior to performing the nonlinear operation.

5. The method of claim 4 wherein the received signals are correlated with a clean replica of themselves prior to performing the filtering operation.

7. The method of claim 1 or 6 wherein the windowed desired frequency domain bands for each FT segment are transferred to a Host.

8. The method of claim 7 where a time domain signal, r_i(t), is constructed at the Host by appending all the windowed desired frequency domain segments and performing an IFT operation on the appended windowed desired frequency domain segments.

9. The method of claim 8 where a plurality of tones in the reconstructed time domain signal, r_i(t), are resolved using SR or Inverse SR algorithms.

6. A method of estimating the location of a Mobile Receiver (MR) comprising the steps of:

receiving a plurality of signals from a plurality of Base Station Transmitters (BSTs) by the MR;

extracting at least one existing tone from each received signal by performing a Fourier Transform (FT) on segments of the received signal, windowing desired frequency domain bands for each segment; and

performing an inverse Fourier Transform (IFT) on the windowed desired frequency domain bands; and

estimating the location of the MR by estimating the phases of the extracted existing tones in each received signal.

10. A method of estimating the location of a MR from a plurality of signals transmitted from a plurality of BSTs, where one or more antennas is used at the MR and in which location of the MR is achieved by combining the signals from all antennas at the MR for location purposes and the use of a technique selected from the group consisting of:

Range positioning (circular multilateration) with round Trip Delay, and

AOA/Range positioning (multi-angulation/circular multilateration) with Round Trip Delay.

11. The method of claim 10 in which more than one antenna is used at the MR.

12. A system to estimate the location of a MR from a plurality of signals transmitted from a plurality of BSTs, where one or more antennas are used at the MR and wherein the system comprises means for implementing a technique selected from the group consisting of:

Range positioning (circular multilateration) with Round Trip Delay, and

AOA/Range positioning (multi-angulation/circular multilateration) with Round Trip Delay, and means for combining the signals from all antennas for location purposes.

13. The system of claim 12 in which more than one antenna is used at the MR.

14. A method of estimating the location of a Mobile Receiver (MR) comprising the steps of:

receiving a plurality of signals from a plurality of Base Station Transmitters (BSTs) by the MR;

performing a nonlinear operation on the plurality of received signals at the MR in order to generate at least one tone for each received signal; and

extracting the at least one tone from each received signal by performing a digital filtering operation on the received signal, wherein the digital filtering operation performs an operation selected from the group consisting of;

a sliding Fourier Transform operation,

a recursive Fourier Transform operation,

an IIR filtering operation; and

an FIR filtering operation.

15. The method of claim 14 wherein the nonlinear operation is selected from the group consisting of:

a quadratic operation;

a delay product operation; and

an absolute value operation.

16. The method of claim 14 where the location operation is performed by estimating the phases of the generated at least one Tone.

17. The method of claim 14 wherein the received signals are filtered prior to performing the nonlinear operation.

18. The method of claim 17 wherein the received signals are correlated with a clean replica of themselves prior to performing the filtering operation.

19. A method of estimating the location of a Mobile Receiver (MR) comprising the steps of:

receiving a plurality of signals from a plurality of Base Station Transmitters (BSTs) by the MR;

extracting at least one existing tone from each received signal by digital filtering the received signal, wherein digital filtering is performed by an operation selected from the group consisting of a sliding Fourier Transform operation, a recursive Fourier Transform operation, an IIR filtering operation; and

an FIR filtering operation; and

estimating the location of the MR by estimating the phases of the extracted existing tones in each received signal.

20. A method of estimating the location of a Mobile Receiver (MR) comprising the steps of:

receiving a plurality of signals from a plurality of Base Station Transmitters (BSTs) by the MR;

performing an operation on the plurality of received signals at the MR in order to extract at least one tone for each received signal;

resolving the extracted tones in the time domain using an inverse superresolution algorithmn, wherein the inverse superresolution algorithm is carried out using a time domain correlator, a time domain window, a Fourier Transform, a frequency domain window, a frequency domain equalizer, and a processor which performs a superresolution algorithm; and

locating the Mobile Receiver using times of arrival of the received signals as estimated using the resolved extracted tones.

21. A method of estimating the location of a Mobile Receiver (MR) comprising the steps of:

receiving a plurality of signals from a plurality of Base Station Transmitters (BSTs) by the MR;

performing an operation on the plurality of received signals at the MR in order to extract at least one tone for each received signal;

resolving the extracted tones in the frequency domain using an inverse superresoluition algorithm, wherein the inverse superresolution algorithm is carried out using a frequency domain correlator, a frequency domain window, an inverse Fourier Transform, a time domain window, a time domain equalizer, and a processor which performs a superresolution algorithm; and

locating the Mobile Receiver using frequencies of arrival of the received signals as estimated using the resolved extracted tones.

22. A system for estimating the location of a Mobile Receiver (MR), the system comprising:

a receiver for receiving a plurality of signals from a plurality of Base Station Transmitters (BSTs) by the MR;

a computing means connected to the receiver by a communication link for performirtg an operation on the plurality of received signals at the MR in order to extract at least one tone for each received signal;

the computing means being configured to resolve the extracted tones in the time domain using an inverse superresolution algorithm, wherein the inverse superresolution algorithm is carried out using a time domain correlator, a time domain window, a Fourier Transform, a frequency domain window, a frequency domain equalizer, and a processor which performs a superresolution algorithm; and

the computing means being configured to locate the MR using the times of arrival of the received signals as estimated using the resolved extracted tones.

23. A system for estimating the location of a Mobile Receiver (MR), the system comprising:

a receiver for receiving a plurality of signals from a plurality of Base Station Transmitters (BSTs) by the MR;

a computing means connected to the receiver by a communication link for performing an operation on the plurality of received signals at the MR in order to extract at least one tone for each received signal;

the computing means being configured to resolve extracted tones in the frequency domain using an inverse superresolution algorithm, wherein the inverse superresolution algorithm is carried out using a frequency domain correlator, a frequency domain window, a Fourier Transform, a time domain window, a time domain equalizer, and a processor which performs a superresolution algorithm; and

the computing means being configured to locate the MR using the frequencies of arrival of the received signals as estimated using the resolved extracted tones.