Patents Assigned to SIRF Technology
  • Patent number: 6453238
    Abstract: A navigation system for tracking the position of an object includes a GPS receiver responsive to GPS signals for periodically providing navigation state measurement updates to a navigation processor. The system also includes a dead-reckoning sensor responsive to movement of the object for providing movement measurements to the navigation processor. The navigation processor determines object navigation states using the navigation state measurement updates and propagates the object navigation states between measurement updates using the movement measurements.
    Type: Grant
    Filed: September 15, 2000
    Date of Patent: September 17, 2002
    Assignee: SiRF Technology, Inc.
    Inventors: Keith J. Brodie, Stephen F. Rounds, Mangesh M. Chansarkar
  • Publication number: 20020116124
    Abstract: The present invention discloses a GPS system that can operate in different modes depending on the network facilities and bandwidth available, the GPS information that can be acquired, or user or system requirements. The modes comprise standalone mode, where a mobile communications device computes the position of the device, an autonomous mode, where the mobile communications device transmits the computed position to a server, application, or PSAP in a communications network, a network aided mode, where the network aides the mobile communications device in determining the position of the device, a network based mode, and other modes.
    Type: Application
    Filed: April 19, 2002
    Publication date: August 22, 2002
    Applicant: SiRF Technology, Inc.
    Inventors: Lionel Jacques Garin, Kanwar Chadha, Gregory Bret Turetzky, Ashutosh Pande
  • Patent number: 6427121
    Abstract: A communications system for determining the position and velocity of an object using a plurality of GPS signals transmitted by a plurality of GPS sources includes an interrogator remote from the object and responsive to the plurality of GPS signals. The interrogator transmits an RF signal including GPS source information and at least one of frequency information and time and code phase information of at least one of the GPS signals. The system also includes a transponder positioned on the object and responsive to the RF signal and the plurality of GPS signals. The transponder tracks one of the plurality of GPS signals in response to the GPS source information and the frequency information and time and code phase information. The transponder generates a correlation snapshot and transmits the snapshot to the interrogator.
    Type: Grant
    Filed: July 12, 2001
    Date of Patent: July 30, 2002
    Assignee: SiRF Technology, Inc.
    Inventor: Keith J. Brodie
  • Patent number: 6427120
    Abstract: The present invention discloses a GPS system that can operate in different modes depending on the network facilities and bandwidth available, the GPS information that can be acquired, or user or system requirements. The modes comprise standalone mode, where a mobile communications device computes the position of the device, an autonomous mode, where the mobile communications device transmits the computed position to a server, application, or PSAP in a communications network, a network aided mode, where the network aides the mobile communications device in determining the position of the device, a network based mode, and other modes.
    Type: Grant
    Filed: February 28, 2001
    Date of Patent: July 30, 2002
    Assignee: SIRF Technology, Inc.
    Inventors: Lionel Jacques Garin, Kanwar Chadha, Gregory Bret Turetzky, Ashutosh Pande
  • Patent number: 6421609
    Abstract: A terrestrial C/A code GPS receiver system derives along track position information while tracking as few as two GPS satellites by use of conventional altitude hold and a cross track hold mode in which the maximum expected deviation of the vehicle from the expected track is estimated by, for example, knowledge or prediction of the width of the roadway or other track. To maintain accuracy, cross track hold is alternated with clock hold to update the cross track estimate when changes in vehicle direction are detected or when a predetermined period has elapsed.
    Type: Grant
    Filed: July 12, 2001
    Date of Patent: July 16, 2002
    Assignee: SiRF Technology, Inc.
    Inventor: Sanjai Kohli
  • Publication number: 20020086684
    Abstract: The present invention discloses a GPS system that can operate in different modes depending on the network facilities and bandwidth available, the GPS information that can be acquired, or user or system requirements. The modes comprise standalone mode, where a mobile communications device computes the position of the device, an autonomous mode, where the mobile communications device transmits the computed position to a server, application, or PSAP in a communications network, a network aided mode, where the network aides the mobile communications device in determining the position of the device, a network based mode, and other modes.
    Type: Application
    Filed: February 5, 2002
    Publication date: July 4, 2002
    Applicant: SiRF Technology, Inc.
    Inventors: Ashutosh Pande, Lionel Jacques Garin, Kanwar Chadha, Gregory Bret Turetzky
  • Patent number: 6400753
    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. Navigation data is updated with detected changes in motion including turns.
    Type: Grant
    Filed: September 5, 2000
    Date of Patent: June 4, 2002
    Assignee: SiRF Technology, Inc.
    Inventors: Sanjai Kohli, Steven Chen, Charles R. Cahn, Mangesh Chansarkar, Greg Turetsky
  • Patent number: 6393046
    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. Navigation data is updated with detected changes in motion including turns.
    Type: Grant
    Filed: April 25, 1997
    Date of Patent: May 21, 2002
    Assignee: SiRF Technology, Inc.
    Inventors: Sanjai Kohli, Steven Chen, Charles R. Cahn, Mangesh Chansarkar, Greg Turetsky
  • Patent number: 6389291
    Abstract: The present invention discloses a GPS system that can operate in different modes depending on the network facilities and bandwidth available, the GPS information that can be acquired, or user or system requirements. The modes comprise standalone mode, where a mobile communications device computes the position of the device, an autonomous mode, where the mobile communications device transmits the computed position to a server, application, or PSAP in a communications network, a network aided mode, where the network aides the mobile communications device in determining the position of the device, a network based mode, and other modes.
    Type: Grant
    Filed: February 8, 2001
    Date of Patent: May 14, 2002
    Assignee: SIRF Technology
    Inventors: Ashutosh Pande, Lionel Jacques Garin, Kanwar Chadha, Gregory Bret Turetzky
  • Patent number: 6366250
    Abstract: A wrist mounted wireless instrument is provided with a wrist strap containing an antenna therein. An electrically conductive shield is disposed in the wrist strap between the antenna and the wrist to shield the antenna from the effects of the body of the user.
    Type: Grant
    Filed: December 9, 1999
    Date of Patent: April 2, 2002
    Assignee: SiRF Technology, Inc.
    Inventor: Richard Joseph McConnell
  • Patent number: 6351711
    Abstract: A GPS receiver includes a satellite receiver/processor having an input that receives input signals from at least one GPS satellite. The output of the receiver/processor provides satellite-related navigation information. A neural network receives the satellite-related information to obtain an output signal representative of receiver-related navigation information. The neural network includes a first node layer connected to a second node layer through a first connection layer and a third node layer connected to the second node layer through a second connection layer. Each of the node layers comprises a plurality of neurons.
    Type: Grant
    Filed: September 14, 2000
    Date of Patent: February 26, 2002
    Assignee: Sirf Technology, Inc.
    Inventor: Mangesh M. Chansarkar
  • Publication number: 20010048388
    Abstract: An autonomous Hardwired Tracking Loop (HWTL) ASIC comprising a HWTL coprocessor provided for implementing most of the receiver processing function for data acquisition and tracking functions of a radio receiver system in dedicated hardware. With the expanded functionality provided by an HWTL coprocessor in the autonomous HWTL ASIC, the interruption of CPU performing the navigation processing is significantly reduced to thereby maximize throughput and minimize power burden on the microprocessor. In the preferred embodiment, the HWTL ASIC also comprises the CPU and a correlator, wherein the correlator provides the high rate greater than approximately 1 KHz signal processing operations, the HWTL coprocessor providing the data acquisition and tracking (medium frequency signal processing) operations, and the CPU thereby freed to provide more bandwidth for lower frequency processing, i.e.
    Type: Application
    Filed: May 31, 2001
    Publication date: December 6, 2001
    Applicant: SiRF Technology, Inc.
    Inventors: Henry D. Falk, Leon Kuo-Liang Peng, Wesley F. Marumo
  • Patent number: 6301545
    Abstract: A communications system for determining the position and velocity of an object using a plurality of GPS signals transmitted by a plurality of GPS sources includes an interrogator remote from the object and responsive to the plurality of GPS signals. The interrogator transmitts an RF signal including GPS source information and at least one of frequency information and time and code phase information of at least one of the GPS signals. The system also includes a transponder positioned on the object and responsive to the RF signal and the plurality of GPS signals. The transponder tracks one of the plurality of GPS signals in response to the GPS source information and the frequency information and time and code phase information. The transponder generates a correlation snapshot and transmits the snapshot to the interrogator.
    Type: Grant
    Filed: April 28, 2000
    Date of Patent: October 9, 2001
    Assignee: SiRF Technology, Inc.
    Inventor: Keith J. Brodie
  • Patent number: 6292749
    Abstract: A terrestrial C/A code GPS receiver system derives along track position information while tracking as few as two GPS satellites by use of conventional altitude hold and a cross track hold mode in which the maximum expected deviation of the vehicle from the expected track is estimated by, for example, knowledge or prediction of the width of the roadway or other track. To maintain accuracy, cross track hold is alternated with clock hold to update the cross track estimate when changes in vehicle direction are detected or when a predetermined period has elapsed.
    Type: Grant
    Filed: December 8, 2000
    Date of Patent: September 18, 2001
    Assignee: SiRF Technology, Inc.
    Inventor: Sanjai Kohli
  • Patent number: 6282231
    Abstract: A CDMA coded, spread spectrum radio signal containing a strong signal and a weak signal is received, and the interference of the strong signal with the weak signal is computed to enhance the ability to track the weak signal. The codes modulating both signals are known, and the weak signal can be predicted. The interference of the strong signal is calculated as the product of the amplitude of the strong signal and the predicted crosscorrelation of the strong signal with the weak signal. The strong signal may be measured, predicted, or acquired through a combination of both methods. The crosscorrelation may be predicted for a range of weak signal values, and the weak signal selected as the prediction producing the greatest received power.
    Type: Grant
    Filed: December 14, 1999
    Date of Patent: August 28, 2001
    Assignee: SiRF Technology, Inc.
    Inventors: Charles P. Norman, Charles R. Cahn
  • Patent number: 6278403
    Abstract: An autonomous Hardwired Tracking Loop (HWTL) ASIC comprising a HWTL coprocessor provided for implementing most of the receiver processing function for data acquisition and tracking functions of a radio receiver system in dedicated hardware. With the expanded functionality provided by an HWTL coprocessor in the autonomous HWTL ASIC, the interruption of CPU performing the navigation processing is significantly reduced to thereby maximize throughput and minimize power burden on the microprocessor. In the preferred embodiment, the HWTL ASIC also comprises the CPU and a correlator, wherein the correlator provides the high rate greater than approximately 1 KHz signal processing operations, the HWTL coprocessor providing the data acquisition and tracking (medium frequency signal processing) operations, and the CPU thereby freed to provide more bandwidth for lower frequency processing, i.e.
    Type: Grant
    Filed: September 17, 1999
    Date of Patent: August 21, 2001
    Assignee: SiRF Technology, Inc.
    Inventors: Leon Kuo-Liang Peng, Henry D. Falk, Wesley F. Marumo
  • Patent number: 6249542
    Abstract: A GPS receiver system determines the presence of trackable signals at code delays less than the prompt delay being tracked for a particular signal and changes the prompt delay to correspond to the smallest code delay having a trackable signal. Trackable signals at large code delays are multipath signals and may be separately tracked to aid in dead reckoning. The trackable signals at code delays not adjacent to the currently tracked prompt delay may be tracked in the same channel as the prompt delay so that all satellite channels are continuously evaluated for multipath signals being tracked or a non-satellite specific channel may be used to sequentially step through the satellite signals to evaluate multipath on a satellite by satellite basis.
    Type: Grant
    Filed: March 27, 1998
    Date of Patent: June 19, 2001
    Assignee: SiRF Technology, Inc.
    Inventors: Sanjai Kohli, Charles R. Cahn
  • Patent number: 6236937
    Abstract: A terrestrial C/A code GPS receiver system derives along track position information while tracking as few as two GPS satellites by use of conventional altitude hold and a cross track hold mode in which the maximum expected deviation of the vehicle from the expected track is estimated by, for example, knowledge or prediction of the width of the roadway or other track. To maintain accuracy, cross track hold is alternated with clock hold to update the cross track estimate when changes in vehicle direction are detected or when a predetermined period has elapsed.
    Type: Grant
    Filed: July 31, 2000
    Date of Patent: May 22, 2001
    Assignee: SiRF Technology, Inc.
    Inventor: Sanjai Kohli
  • Patent number: 6198765
    Abstract: A spread spectrum receiver uses a comparison of the magnitude of the code correlation amplitudes at equal power at a one chip spacing to the magnitude at a central position there between to determine if multipath interference is present. The lead or lag error from constructive or destructive multipath interference may also be determined. Inaccuracies due to such interference may then be corrected or minimized by, for example, determining the residual code phase error and/or the prompt or accurate code phase delay.
    Type: Grant
    Filed: September 12, 1997
    Date of Patent: March 6, 2001
    Assignee: SiRF Technologies, Inc.
    Inventors: Charles R. Cahn, Mangesh Chansarkar, Sanjai Kohli
  • Patent number: 6125325
    Abstract: A terrestrial C/A code GPS receiver system derives along track position information while tracking as few as two GPS satellites by use of conventional altitude hold and a cross track hold mode in which the maximum expected deviation of the vehicle from the expected track is estimated by, for example, knowledge or prediction of the width of the roadway or other track. To maintain accuracy, cross track hold is alternated with clock hold to update the cross track estimate when changes in vehicle direction are detected or when a predetermined period has elapsed.
    Type: Grant
    Filed: July 25, 1997
    Date of Patent: September 26, 2000
    Assignee: SiRF Technology, Inc.
    Inventor: Sanjai Kohli