Steven Chen

US Patent:

6393046, May 21, 2002

Filed:

Apr 25, 1997

Appl. No.:

08/846067

Inventors:

Sanjai Kohli - Manhattan Beach CA
Steven Chen - Cerritos CA
Charles R. Cahn - Manhattan Beach CA
Mangesh Chansarkar - Santa Clara CA
Greg Turetsky - San Jose CA

Assignee:

SiRF Technology, Inc. - San Jose CA

International Classification:

H04L 2330

US Classification:

375134, 375130, 375137, 375140, 375142

Abstract:

A terrestrial C/A code GPS receiver system digitally samples, filters and stores a segment of 11 half chips of the received composite as a binary number and multiplexes this number for parallel correlation with each of a series of multibit code replicas for the satellites to be tracked. Each of the time delay specific correlation products are accumulated in a cell of a memory matrix so that at least twenty two delays for each satellite may be evaluated each code period providing fast reacquisition, even within a city intersection, as well as correction of multipath tracking and multipath interference. All cells of the memory matrix may be used for a acquisition of a single satellite in about 4 ms. Two satellite tracking, in addition to altitude hold, uses cross track hold alternating with clock hold to update the cross track estimate. Single satellite tracking uses cross track and clock hold together.

US Patent:

6400753, Jun 4, 2002

Filed:

Sep 5, 2000

Appl. No.:

09/655633

Inventors:

Sanjai Kohli - Manhattan Beach CA
Steven Chen - Cerritos CA
Charles R. Cahn - Manhattan Beach CA
Mangesh Chansarkar - Santa Clara CA
Greg Turetsky - San Jose CA

Assignee:

SiRF Technology, Inc. - San Jose CA

International Classification:

H04L 2730

US Classification:

375134, 375130, 375137, 375140, 375142

Abstract:

A terrestrial C/A code GPS receiver system digitally samples, filters and stores a segment of 11 half chips of the received composite as a binary number and multiplexes this number for parallel correlation with each of a series of multibit code replicas for the satellites to be tracked. Each of the time delay specific correlation products are accumulated in a cell of a memory matrix so that at least twenty two delays for each satellite may be evaluated each code period providing fast reacquisition, even within a city intersection, as well as correction of multipath tracking and multipath interference. All cells of the memory matrix may be used for a acquisition of a single satellite in about 4 ms. Two satellite tracking, in addition to altitude hold, uses cross track hold alternating with clock hold to update the cross track estimate. Single satellite tracking uses cross track and clock hold together.

US Patent:

6522682, Feb 18, 2003

Filed:

Mar 2, 1999

Appl. No.:

09/260440

Inventors:

Sanjai Kohli - Manhattan Beach CA
Steven Chen - Cerritos CA

Assignee:

SiRF Technology, Inc. - San Jose CA

International Classification:

H04B 169

US Classification:

375142, 375150, 34235708, 701213

Abstract:

A spread spectrum receiver processes signals from a plurality of sources modulated by different spread spectrum codes by sampling the signals as received to produce an integer series of sampling segments at a sampling rate at least twice a chip rate of the codes, each sampling segment containing an integer number of bits representing a fraction of a chip of the codes, time division multiplexing each sample segment into a number of channels, correlating the bits in each sample segment in each channel in parallel with a source specific series of locally generated sequential code samples differing by one bit, summing each parallel correlation, and accumulating the summed parallel correlations for each code sample in each channel at at least the chip rate to derive data related to each of the sources.

US Patent:

6633814, Oct 14, 2003

Filed:

Dec 22, 2000

Appl. No.:

09/747394

Inventors:

Sanjai Kohli - Manhattan Beach CA
Steven Chen - Cerritos CA
Charles R. Cahn - Manhattan Beach CA
Mangesh Chansarkar - Santa Clara CA
Greg Turetsky - San Jose CA

Assignee:

SiRf Technology, Inc. - San Jose CA

International Classification:

G01C 2100

US Classification:

701213

Abstract:

A terrestrial C/A code GPS receiver system digitally samples, filters and stores a segment of 11 half chips of the received composite as a binary number and multiplexes this number for parallel correlation with each of a series of multibit code replicas for the satellites to be tracked. Each of the time delay specific correlation products are accumulated in a cell of a memory matrix so that at least twenty two delays for each satellite may be evaluated each code period providing fast reacquisition, even within a city intersection, as well as correction of multipath tracking and multipath interference. All cells of the memory matrix may be used for a acquisition of a single satellite in about 4 ms. Two satellite tracking, in addition to altitude hold, uses cross track hold alternating with clock hold to update the cross track estimate. Single satellite tracking uses cross track and clock hold together.

US Patent:

6724811, Apr 20, 2004

Filed:

Mar 13, 2002

Appl. No.:

10/099497

Inventors:

Sanjai Kohli - Manhattan Beach CA
Steven Chen - Cerritos CA
Charles R. Cahn - Manhattan Beach CA
Mangesh Chansarkar - Santa Clara CA
Greg Turetsky - San Jose CA

Assignee:

SiRF Technology, Inc. - San Jose CA

International Classification:

H04B 169

US Classification:

375150, 375130, 375134, 375137, 375140, 375142

Abstract:

A terrestrial C/A code GPS receiver system digitally samples, filters and stores a segment of 11 half chips of the received composite as a binary number and multiplexes this number for parallel correlation with each of a series of multibit code replicas for the satellites to be tracked. Each of the time delay specific correlation products are accumulated in a cell of a memory matrix so that at least twenty two delays for each satellite may be evaluated each code period providing fast reacquisition, even within a city intersection, as well as correction of multipath tracking and multipath interference. All cells of the memory matrix may be used for an acquisition of a single satellite in about 4 ms. Two satellite tracking, in addition to altitude hold, uses cross track hold alternating with clock hold to update the cross track estimate. Single satellite tracking uses cross track and clock hold together.

US Patent:

6748015, Jun 8, 2004

Filed:

Mar 18, 2002

Appl. No.:

10/101138

Inventors:

Sanjai Kohli - Manhattan Beach CA
Steven Chen - Cerritos CA

Assignee:

SiRF Technology, Inc. - San Jose CA

International Classification:

H04B 169

US Classification:

375150, 375149

Abstract:

A terrestrial C/A code GPS receiver system digitally samples, filters and stores a segment of 11 half chips of the received composite as a binary number and multiplexes this number for parallel correlation with each of a series of multibit code replicas for the satellites to be tracked. Each of the time delay specific correlation products are accumulated in a cell of a memory matrix so that at least twenty two delays for each satellite may be evaluated each code period providing fast reacquisition, even within a city intersection, as well as correction of multipath tracking and multipath interference. All cells of the memory matrix may be used for an acquisition of a single satellite in about 4 ms. Two satellite tracking, in addition to altitude hold, uses cross track hold alternating with clock hold to update the cross track estimate. Single satellite tracking uses cross track and clock hold together.

US Patent:

6788735, Sep 7, 2004

Filed:

Dec 16, 2002

Appl. No.:

10/320932

Inventors:

Sanjai Kohli - Manhattan Beach CA
Steven Chen - Cerritos CA

Assignee:

SiRF Technology, Inc. - San Jose CA

International Classification:

H04B 1500

US Classification:

375150, 375130, 375142, 375147

Abstract:

A spread spectrum receiver processes signals from a plurality of sources modulated by different spread spectrum codes by sampling the signals as received to produce an integer series of sampling segments at a sampling rate at least twice a chip rate of the codes, each sampling segment containing an integer number of bits representing a fraction of a chip of the codes, time division multiplexing each sample segment into a number of channels, correlating the bits in each sample segment in each channel in parallel with a source specific series of locally generated sequential code samples differing by one bit, summing each parallel correlation, and accumulating the summed parallel correlations for each code sample in each channel at a rate at least equal to the chip rate to derive data related to each of the sources.

US Patent:

D497903, Nov 2, 2004

Filed:

Jan 16, 2004

Appl. No.:

29/197568

Inventors:

Eric Y. Chin - Irvine CA
Steven Chen - Irvine CA

Assignee:

Realworld Technology Inc. - City of Industry CA

International Classification:

1401

US Classification:

D14216, D14211, D14207