Patents by Inventor Liwen Dai

Liwen Dai has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11808861
    Abstract: A first pair of a wide-lane (WL), zero-difference (ZD) bias filter and corresponding supplemental WL bias predictive filter determines the time-variant wide-lane bias for a corresponding satellite based on adaptive estimation responsive to tuned dynamic noise provided by the supplemental wide-lane bias predictive filter for each satellite. A second pair of narrow-lane (NL), zero-difference (ZD) bias filter and corresponding NL bias filter/code-phase bias filter determines the time-variant narrow-lane bias (e.g., refraction corrected (NL) code-phase bias) for a corresponding satellite based on adaptive estimation on adaptive estimation responsive to tuned dynamic noise within a narrow-lane bias/code-phase bias filter for each satellite. The electronic data processor of a data processing center is configured to provide a correction signal comprising the wide-lane ambiguities, the time-variant wide-lane bias and the narrow-lane ambiguities and the time-variant narrow lane bias.
    Type: Grant
    Filed: September 22, 2021
    Date of Patent: November 7, 2023
    Assignee: Deere & Company
    Inventors: Liwen Dai, Yiqun Chen
  • Publication number: 20230288577
    Abstract: The system and method facilitates Real-Time-Kinematic (RTK) GNSS with long baseline between a rover receiver and a base station receiver, even in the presence of scintillation or ionospheric disturbances that spatially fluctuate. Residual atmospheric errors can be estimated by a dual error model in a filter to promote efficient fixing or resolution of carrier phase ambiguities.
    Type: Application
    Filed: May 13, 2022
    Publication date: September 14, 2023
    Inventors: Yufeng Zhang, Liwen Dai
  • Publication number: 20230288576
    Abstract: The system and method facilitates Real-Time-Kinematic (RTK) GNSS with long baseline between a rover receiver and a base station receiver, even in the presence of scintillation or ionospheric disturbances that spatially fluctuate. Residual atmospheric errors can be estimated by a dual error model in a filter to promote efficient fixing or resolution of carrier phase ambiguities.
    Type: Application
    Filed: May 13, 2022
    Publication date: September 14, 2023
    Inventors: Yufeng Zhang, Liwen Dai
  • Publication number: 20220252732
    Abstract: A first pair of a wide-lane (WL), zero-difference (ZD) bias filter and corresponding supplemental WL bias predictive filter determines the time-variant wide-lane bias for a corresponding satellite based on adaptive estimation responsive to tuned dynamic noise provided by the supplemental wide-lane bias predictive filter for each satellite. A second pair of narrow-lane (NL), zero-difference (ZD) bias filter and corresponding NL bias filter/code-phase bias filter determines the time-variant narrow-lane bias (e.g., refraction corrected (NL) code-phase bias) for a corresponding satellite based on adaptive estimation on adaptive estimation responsive to tuned dynamic noise within a narrow-lane bias/code-phase bias filter for each satellite. The electronic data processor of a data processing center is configured to provide a correction signal comprising the wide-lane ambiguities, the time-variant wide-lane bias and the narrow-lane ambiguities and the time-variant narrow lane bias.
    Type: Application
    Filed: September 22, 2021
    Publication date: August 11, 2022
    Inventors: Liwen Dai, Yiqun Chen
  • Patent number: 10379225
    Abstract: A satellite navigation receiver and associated methods are described that can provide improved integer ambiguity resolution and more accurate positioning information. A modified BIE process may be utilized to enable the receiver to perform the integer ambiguity resolution more optimally. The output of the modified BIE process may be time-domain smoothed to provide a solution which is smoother in ambiguity space, and therefore also provide a position solution that is smoother in time. Transitions between an ambiguity-determined solution to a float solution, when necessary, may be smoothed in time. A weighting scheme may dynamically blend the ambiguity-determined solution and the float solution to leverage the advantages of both solutions, such as faster pull-in, higher accuracy, and more stable and smooth performance.
    Type: Grant
    Filed: September 29, 2016
    Date of Patent: August 13, 2019
    Assignee: DEERE & COMPANY
    Inventors: Liwen Dai, Michael Zeitzew
  • Patent number: 10222484
    Abstract: A satellite navigation receiver and associated methods are described that can provide improved integer ambiguity resolution and more accurate positioning information. A modified BIE process may be utilized to enable the receiver to perform the integer ambiguity resolution more optimally. The output of the modified BIE process may be time-domain smoothed to provide a solution which is smoother in ambiguity space, and therefore also provide a position solution that is smoother in time. Transitions between an ambiguity-determined solution to a float solution, when necessary, may be smoothed in time. A weighting scheme may dynamically blend the ambiguity-determined solution and the float solution to leverage the advantages of both solutions, such as faster pull-in, higher accuracy, and more stable and smooth performance.
    Type: Grant
    Filed: September 29, 2016
    Date of Patent: March 5, 2019
    Assignee: DEERE & COMPANY
    Inventors: Liwen Dai, Michael Zeitzew
  • Patent number: 10222483
    Abstract: A satellite navigation receiver and associated methods are described that can provide improved integer ambiguity resolution and more accurate positioning information. A modified BIE process may be utilized to enable the receiver to perform the integer ambiguity resolution more optimally. The output of the modified BIE process may be time-domain smoothed to provide a solution which is smoother in ambiguity space, and therefore also provide a position solution that is smoother in time. Transitions between an ambiguity-determined solution to a float solution, when necessary, may be smoothed in time. A weighting scheme may dynamically blend the ambiguity-determined solution and the float solution to leverage the advantages of both solutions, such as faster pull-in, higher accuracy, and more stable and smooth performance.
    Type: Grant
    Filed: September 29, 2016
    Date of Patent: March 5, 2019
    Assignee: DEERE & COMPANY
    Inventors: Liwen Dai, Michael Zeitzew
  • Publication number: 20170269228
    Abstract: A satellite navigation receiver and associated methods are described that can provide improved integer ambiguity resolution and more accurate positioning information. A modified BIE process may be utilized to enable the receiver to perform the integer ambiguity resolution more optimally. The output of the modified BIE process may be time-domain smoothed to provide a solution which is smoother in ambiguity space, and therefore also provide a position solution that is smoother in time. Transitions between an ambiguity-determined solution to a float solution, when necessary, may be smoothed in time. A weighting scheme may dynamically blend the ambiguity-determined solution and the float solution to leverage the advantages of both solutions, such as faster pull-in, higher accuracy, and more stable and smooth performance.
    Type: Application
    Filed: September 29, 2016
    Publication date: September 21, 2017
    Inventors: Liwen Dai, Michael Zeitzew
  • Publication number: 20170269230
    Abstract: A satellite navigation receiver and associated methods are described that can provide improved integer ambiguity resolution and more accurate positioning information. A modified BIE process may be utilized to enable the receiver to perform the integer ambiguity resolution more optimally. The output of the modified BIE process may be time-domain smoothed to provide a solution which is smoother in ambiguity space, and therefore also provide a position solution that is smoother in time. Transitions between an ambiguity-determined solution to a float solution, when necessary, may be smoothed in time. A weighting scheme may dynamically blend the ambiguity-determined solution and the float solution to leverage the advantages of both solutions, such as faster pull-in, higher accuracy, and more stable and smooth performance.
    Type: Application
    Filed: September 29, 2016
    Publication date: September 21, 2017
    Inventors: Liwen Dai, Michael Zeitzew
  • Publication number: 20170269229
    Abstract: A satellite navigation receiver and associated methods are described that can provide improved integer ambiguity resolution and more accurate positioning information. A modified BIE process may be utilized to enable the receiver to perform the integer ambiguity resolution more optimally. The output of the modified BIE process may be time-domain smoothed to provide a solution which is smoother in ambiguity space, and therefore also provide a position solution that is smoother in time. Transitions between an ambiguity-determined solution to a float solution, when necessary, may be smoothed in time. A weighting scheme may dynamically blend the ambiguity-determined solution and the float solution to leverage the advantages of both solutions, such as faster pull-in, higher accuracy, and more stable and smooth performance.
    Type: Application
    Filed: September 29, 2016
    Publication date: September 21, 2017
    Inventors: Liwen Dai, Michael Zeitzew
  • Patent number: 9599721
    Abstract: A primary phase measurement device measures a first carrier phase and a second carrier phase of carrier signals received by the location-determining receiver. A secondary phase measurement device measures the third carrier phase and the fourth carrier phase of other carrier signals. A real time kinematic engine estimates a first integer ambiguity set associated with the measured first carrier phase and a second integer ambiguity set associated with the measured second carrier phase. The real time kinematic engine estimates a third ambiguity set associated with the measured third carrier phase and a fourth ambiguity set associated with the measured fourth carrier phase. A compensator is capable of compensating for the inter-channel bias in at least one of the third ambiguity set and the fourth ambiguity set by modeling a predictive filter in accordance with various inputs or states of the filter estimated by an estimator.
    Type: Grant
    Filed: December 14, 2012
    Date of Patent: March 21, 2017
    Assignee: DEERE & COMPANY
    Inventors: Liwen Dai, Chaochao Wang
  • Patent number: 8803736
    Abstract: A primary phase measurement device measures a first carrier phase and a second carrier phase of carrier signals received by the location-determining receiver. A secondary phase measurement device measures the third carrier phase and the fourth carrier phase of other carrier signals. A real time kinematic engine estimates a first integer ambiguity set associated with the measured first carrier phase and a second integer ambiguity set associated with the measured second carrier phase. The real time kinematic engine estimates a third ambiguity set associated with the measured third carrier phase and a fourth ambiguity set associated with the measured fourth carrier phase. A compensator is capable of compensating for the inter-channel bias in at least one of the third ambiguity set and the fourth ambiguity set by modeling a predictive filter in accordance with various inputs or states of the filter estimated by an estimator.
    Type: Grant
    Filed: April 27, 2010
    Date of Patent: August 12, 2014
    Assignee: Navcom Technology, Inc.
    Inventors: Liwen Dai, Chaochao Wang
  • Patent number: 8766848
    Abstract: A method and system for estimating the position comprises measuring a first carrier phase of a first carrier signal and a second carrier phase of a second carrier signal received by a location-determining receiver. A primary real time kinematic (RTK) engine or receiver data processing system estimates a primary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carder phase. A quality evaluator determines if a primary integer ambiguity set is resolved correctly to the predefined reliability rate during an earlier evaluation period. A secondary real time kinematic (RTK) engine or receiver data processing system estimates a secondary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carrier phase during a later period following the earlier evaluation period.
    Type: Grant
    Filed: January 29, 2013
    Date of Patent: July 1, 2014
    Assignee: Navcom Technology, Inc.
    Inventors: Liwen Dai, Chaochao Wang, Daniel Eslinger
  • Patent number: 8665145
    Abstract: A system and method for determining the heading angle of a vehicle includes first and second antennas associated with the vehicle. The first and second antennas are configured to receive signals comprising global positioning system data. A receiver front end is configured to receive the signals comprising global positioning system data. An electronic data processor is capable of receiving the global positioning system data from the receiver front end. The data processor is configured or programmed to execute a method to determine the attitude of the vehicle which may include the heading angle of the vehicle.
    Type: Grant
    Filed: April 25, 2011
    Date of Patent: March 4, 2014
    Assignee: Navcom Technology, Inc.
    Inventors: Liwen Dai, Yunfeng Shao, Daniel J. Eslinger
  • Publication number: 20130265192
    Abstract: A method and system for estimating the position comprises measuring a first carrier phase of a first carrier signal and a second carrier phase of a second carrier signal received by a location-determining receiver. A primary real time kinematic (RTK) engine or receiver data processing system estimates a primary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carder phase. A quality evaluator determines if a primary integer ambiguity set is resolved correctly to the predefined reliability rate during an earlier evaluation period. A secondary real time kinematic (RTK) engine or receiver data processing system estimates a secondary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carrier phase during a later period following the earlier evaluation period.
    Type: Application
    Filed: January 29, 2013
    Publication date: October 10, 2013
    Inventors: Liwen Dai, Chaochao Wang, Daniel Eslinger
  • Patent number: 8427365
    Abstract: A method and system for estimating the position comprises measuring a first carrier phase of a first carrier signal and a second carrier phase of a second carrier signal received by a location-determining receiver. A primary real time kinematic (RTK) engine or receiver data processing system estimates a primary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carrier phase. A quality evaluator determines if a primary integer ambiguity set is resolved correctly to the predefined reliability rate during an earlier evaluation period. A secondary real time kinematic (RTK) engine or receiver data processing system estimates a secondary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carrier phase during a later period following the earlier evaluation period.
    Type: Grant
    Filed: April 27, 2010
    Date of Patent: April 23, 2013
    Assignee: Navcom Technology, Inc.
    Inventors: Liwen Dai, Chaochao Wang, Daniel J. Eslinger
  • Publication number: 20110267225
    Abstract: A system and method for determining the heading angle of a vehicle includes first and second antennas associated with the vehicle. The first and second antennas are configured to receive signals comprising global positioning system data. A receiver front end is configured to receive the signals comprising global positioning system data. An electronic data processor is capable of receiving the global positioning system data from the receiver front end. The data processor is configured or programmed to execute a method to determine the attitude of the vehicle which may include the heading angle of the vehicle.
    Type: Application
    Filed: July 19, 2010
    Publication date: November 3, 2011
    Inventors: Liwen Dai, Yunfeng Shao, Daniel J. Eslinger
  • Publication number: 20110267227
    Abstract: A system and method for determining the heading angle of a vehicle includes first and second antennas associated with the vehicle. The first and second antennas are configured to receive signals comprising global positioning system data. A receiver front end is configured to receive the signals comprising global positioning system data. An electronic data processor is capable of receiving the global positioning system data from the receiver front end. The data processor is configured or programmed to execute a method to determine the attitude of the vehicle which may include the heading angle of the vehicle.
    Type: Application
    Filed: April 25, 2011
    Publication date: November 3, 2011
    Inventors: Liwen Dai, Yunfeng Shao, Daniel J. Eslinger
  • Publication number: 20110210889
    Abstract: A primary phase measurement device measures a first carrier phase and a second carrier phase of carrier signals received by the location-determining receiver. A secondary phase measurement device measures the third carrier phase and the fourth carrier phase of other carrier signals. A real time kinematic engine estimates a first integer ambiguity set associated with the measured first carrier phase and a second integer ambiguity set associated with the measured second carrier phase. The real time kinematic engine estimates a third ambiguity set associated with the measured third carrier phase and a fourth ambiguity set associated with the measured fourth carrier phase. A compensator is capable of compensating for the inter-channel bias in at least one of the third ambiguity set and the fourth ambiguity set by modeling a predictive filter in accordance with various inputs or states of the filter estimated by an estimator.
    Type: Application
    Filed: April 27, 2010
    Publication date: September 1, 2011
    Inventors: Liwen Dai, Chaochao Wang
  • Publication number: 20110187598
    Abstract: A method and system for estimating the position comprises measuring a first carrier phase of a first carrier signal and a second carrier phase of a second carrier signal received by a location-determining receiver. A primary real time kinematic (RTK) engine or receiver data processing system estimates a primary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carrier phase. A quality evaluator determines if a primary integer ambiguity set is resolved correctly to the predefined reliability rate during an earlier evaluation period. A secondary real time kinematic (RTK) engine or receiver data processing system estimates a secondary integer ambiguity set associated with at least one of the measured first carrier phase and the measured second carrier phase during a later period following the earlier evaluation period.
    Type: Application
    Filed: April 27, 2010
    Publication date: August 4, 2011
    Inventors: Liwen Dai, Chaochao Wang, Daniel J. Eslinger