Xiangdong Lin

US Patent:

7551133, Jun 23, 2009

Filed:

Apr 5, 2007

Appl. No.:

11/696920

Inventors:

Xiangdong Lin - Irvine CA, US
Gengsheng Zhang - Cupertino CA, US
Mangesh Chansarkar - Irvine CA, US
Daniel Liao - Irvine CA, US
Lionel Garin - Palo Alto CA, US

Assignee:

SiRF Technology, Inc. - San Jose CA

International Classification:

G01S 5/14
G01C 21/00

US Classification:

34235712, 701213

Abstract:

A method for GPS navigation which uses an interacting multiple-model (IMM) estimator with a probabilistic data association filter (PDAF) improves navigation performance. The method includes (a) providing two or more models of GPS navigation, with each model characterized by a model state vector which is updated periodically, (b) providing for each model a corresponding filter for deriving, for each period, a current value for the corresponding model state vector based on current measurements made on parameters affecting the corresponding state vector; and (c) applying an interacting multiple model (IMM) estimator to provide, for each period, a current value for a system state vector using the current values of the model state vectors for that period and their corresponding filters. Each model state vector may include one or more of the following: variables: 3-dimensional position, 3-dimensional velocity, satellite clock bias, satellite clock drifts and one or more other satellite parameters. The current value of the system state vector may be a weighted average of the current values of the model state vectors, where the weights are a set of mode probabilities.

US Patent:

7821454, Oct 26, 2010

Filed:

Nov 20, 2007

Appl. No.:

11/942912

Inventors:

Gang Xie - Fullerton CA, US
Mangesh Chansarkar - Irvine CA, US
Daniel Liao - Irvine CA, US
Xiangdong Lin - Irvine CA, US

Assignee:

SiRF Technology, Inc. - San Jose CA

International Classification:

G01S 19/20
G01S 19/21
G01S 19/22

US Classification:

34235758, 34235759, 34235761

Abstract:

Systems and methods for detecting global positioning system (GPS) measurement errors are provided. In this regard, a representative system, among others, includes a navigation device that is configured to receive GPS signals from signal sources, the navigation device being configured to calculate pseudoranges (PRs) and delta ranges (DRs) based on the received GPS signals, the navigation device including a consistency check algorithm that is configured to: determine mismatches between the respective calculated PRs and DRs, and indicate that an error exists in the respective calculated PRs and DRs based on their mismatch and mismatch accumulations. This algorithm can be independent of navigation state and is capable of detecting slow-changing errors.

US Patent:

7974642, Jul 5, 2011

Filed:

Feb 20, 2007

Appl. No.:

11/676927

Inventors:

Xiangdong Lin - Irvine CA, US
Marlene Wan - Sunnyvale CA, US
Lionel Garin - Palo Alto CA, US

Assignee:

SiRF Technology, Inc. - San Jose CA

International Classification:

H04Q 5/00

US Classification:

4554566, 4554221, 455440, 4554561, 4554565

Abstract:

Systems and methods for estimating a cell center location in a wireless communication system having all interface to a satellite positioning system (“SPS”) such as for example, a Geosynchronous Positioning System (“GPS”). The wireless communication system provides service to mobile stations within a cell, each mobile station includes a SPS receiver. Examples of the systems and methods for estimating a cell center location analyze the mobile station locations in a cell as a uniform distribution of mobile station locations and calculate a statistical measure characterizing the mobile station locations as a function of the mobile station locations. In one example, the statistical measure is a maximum likelihood mobile station location. In another example, the statistical measure is the mean mobile station location in the cell. The estimated cell center location may be used to approximate the location of the mobile station during a warm or cold restart of the SPS receiver part of the mobile station.

US Patent:

8165607, Apr 24, 2012

Filed:

Dec 22, 2006

Appl. No.:

11/645114

Inventors:

Xiangdong Lin - Irvine CA, US
Mangesh Chansarkar - Sunnyvale CA, US
Marlene Wan - Sunnyvale CA, US
Lionel Garin - Palo Alto CA, US

Assignee:

CSR Technology Inc. - San Jose CA

International Classification:

H04W 24/00

US Classification:

4554566, 455457, 455440, 4554221, 4554561

Abstract:

Systems and methods for estimating a cell center location in a wireless communication system having an interface to a satellite positioning system (“SPS”) such as for example, a Geosynchronous Positioning System (“GPS”). The wireless communication system provides service to mobile stations within a cell, each mobile station includes a SPS receiver. Examples of the systems and methods for estimating a cell center location analyze the mobile station locations in a cell as a uniform distribution of mobile station locations and calculate a statistical measure characterizing the mobile station locations as a function of the mobile station locations. In one example, the statistical measure is a maximum likelihood mobile station location. In another example, the statistical measure is the mean mobile station location in the cell. The estimated cell center location may be used to approximate the location of the mobile station during a warm or cold restart of the SPS receiver part of the mobile station.

US Patent:

20130321202, Dec 5, 2013

Filed:

May 30, 2012

Appl. No.:

13/484217

Inventors:

Xiangdong Lin - Irvine CA, US
David Allan Tuck - San Clemente CA, US
Mangesh Chansarkar - Irvine CA, US

Assignee:

CSR Technology Inc. - Sunnyvale CA

International Classification:

G01S 19/22

US Classification:

34235761

Abstract:

The present invention relates generally to methods and apparatuses for estimating and correcting for multipath in GNSS navigation systems. According to some aspects, the invention takes advantage of situations where position and estimated position error are reasonably stable so as to detect when large multipath errors are present with confidence. After detection, the slowly varying biases from multipath or other un-modeled sources can be modeled separately from the navigation state. This makes it possible to keep the measurements in the solution without biasing the navigation state and further ignores the long-term biases for use over short-term periods with minimized pseudorange error when necessary.