Method of position determination

• US 7,453,394 B2
• Filed: 09/24/2004
• Issued: 11/18/2008
• Est. Priority Date: 09/27/2003
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Rosenfeld, Josi
• Primary Examiner(s): Tarcza; Thomas H.
• Assistant Examiner(s): LIU, HARRY K
• Application Number:
  US10/573,719
• Publication Number:
  US 20070075901A1
• Time in Patent Office: 1,516 Days
• Field of Search: 34235701-35717
• US Class Current: 342/357.25
• CPC Class Codes: G01S 19/22 Multipath-related issues
• CPC Class Codes: G01S 19/42 Determining position
• CPC Class Codes: G01S 5/0218 Multipath in signal reception

Abstract

A device includes an antenna for receiving an incoming signal. A multiplier multiplies the incoming signal with an output from a carrier generator in order to mix down signal the incoming signal. The output of the multiplier is provided to correlators for sequential correlation with a replica code of the mixed down signal provided from a code generator, in order to produce correlation data including I (imaginary) and Q (real) channels. The correlation data is then passed to a signal processor which adjusts appropriately both the code generator and the carrier generator to provide accurate position measurement in indoor environments with multiple diffuse reflections.

Claims

1. A method of position determination in a radio system, the method comprising the acts of:

multiplying a signal received by a multiplier with a carrier signal from a carrier generator to form a mixed down signal;

correlating the mixed down signal with a replica signal from a code generator to form a correlated signal;

processing the correlated signal with an optimization function comprising an exponential term in combination with a second term to form an output signal that provides a position measurement in indoor environments with multiple diffuse reflections; and

feeding back the output signal to control the carrier generator and the code generator for improving accuracy of the position measurement;

wherein the exponential term is in the form Be<sup>−

α

t</sup> and the second term is of the form;

2. The method according to claim 1, further comprising the act of fitting the optimization function and a Line-of Sight correlation function with a set of parameters.

3. The method according to claim 1 comprising first operating a multipath mitigation technique to effect correlation of the received and replica signals.

4. The method according to claim 3, wherein the multipath mitigation technique comprises a Multipath Estimating Delay Locks Loop technique.

5. The method according to claim 3, wherein the multipath mitigation technique comprises a Minimum Mean Square Error technique.

6. A computer program product directly loadable into the internal memory of a digital computer, comprising software code portions for performing the method of claim 1 when said product is run on a computer.

7. A computer program directly loadable into the internal memory of a digital computer, comprising software code portions for performing the method of claim 1 when said program is run on a computer.

8. An apparatus for position determination of a radio system, the apparatus comprising:

a carrier generator for providing a carrier signal;

a multiplier for multiplying a received signal with the carrier signal to form a mixed down signal;

means to correlate the mixed down signal with a replica signal and form a correlated signal;

a code generator to provide the replica signal; and

means to process the correlated signal with an optimization function comprising an exponential term in combination with a second term to form an output signal that provides a position measurement in indoor environments with multiple diffuse reflections;

wherein the output signal is fed back to control the carrier generator and the code generator for improving accuracy of the position measurement;

wherein the exponential term is in the form Be<sup>−

α

t</sup> and the second term is of the form;

9. The apparatus according to claim 8, further comprising means to fit the optimization function and a Line-of Sight correlation function with a set of parameters.

10. The apparatus according to claim 8, further comprising means to first operate a multipath mitigation technique to effect correlation of the received and replica signals.

11. The apparatus according to claim 10, wherein the multipath mitigation technique comprises a Multipath Estimating Delay Locks Loop technique.

12. The apparatus according to claim 10, wherein the multipath mitigation technique comprises a Minimum Mean Square Error technique.