Patents Assigned to SiRF Technologies, Inc.
  • Patent number: 7729413
    Abstract: A system and a method to track GPS (Global Positioning System) satellite signal in a GPS receiver that includes an expanded capture window to rapidly reacquire the satellite signal after the satellite signal has been obstructed or when there is other type of signal loss. The expanded capture window includes a plurality of additional early and late correlations for maintaining synchronization of the GPS signal with a generated replica signal when positional error has accumulated during the time of the signal loss. The plurality of additional early and late correlations may be delayed from each other by a multiple of a fraction of a chip and may be performed in one or multiple channels of the GPS receiver. The adjoining code samples in the replica signal may also be offset by a fraction of a chip or by a multiple of the fraction of a chip.
    Type: Grant
    Filed: April 30, 2004
    Date of Patent: June 1, 2010
    Assignee: SirF Technology, Inc.
    Inventors: Sanjai Kohli, Steven Chen, Charles R. Cahn, Mangesh Chansarkar, Greg Turetsky
  • Patent number: 7724612
    Abstract: Systems and methods for obtaining corrected time information in a GPS-enabled device connected to a mobile handset via a short-range wireless network, such as a Bluetooth™ Piconet™. The mobile handset includes a GPS time and a network clock synchronized with a network clock in a short-range wireless network interface in the GPS-enabled device. The GPS-enabled device may send requests for time information to the mobile handset. The mobile handset receives the request and latches the network clock time and the GPS time. The captured network clock time and GPS times are sent to the GPS-enabled device in response to the request. The GPS-enabled device subtracts the captured network clock time from its own network clock time and adds the difference to the captured GPS time to obtain a corrected GPS time.
    Type: Grant
    Filed: April 20, 2007
    Date of Patent: May 25, 2010
    Assignee: Sirf Technology, Inc.
    Inventor: Syed Khalid Azim
  • Patent number: 7724186
    Abstract: An Aided Location Communication System (“ALCS”) is described. The ALCS may include a geolocation server including a non-GPS position server, at least one server aiding database, server position-determination module, and a server fusion module. The ALCS may also include an Aided Location Communication Device (“ALCD”) including a communication section in signal communication with the geolocation server, and a position-determination section having a GPS Engine.
    Type: Grant
    Filed: June 29, 2007
    Date of Patent: May 25, 2010
    Assignee: SIRF Technology, Inc.
    Inventors: Marlene Wan, Lionel Garin, Gengsheng Zhang
  • Patent number: 7720642
    Abstract: The present invention discloses a method and an apparatus for improving measurement fault detection in a sequential measurement processing estimator, and is particularly applied to Global Positioning Receivers.
    Type: Grant
    Filed: February 18, 2008
    Date of Patent: May 18, 2010
    Assignee: SiRF Technology, Inc.
    Inventor: Keith Jacob Brodie
  • Patent number: 7719464
    Abstract: A system and method for providing aiding information to a satellite positioning system (“SPS”) receiver. A digital satellite radio system satellite receives aiding information communicated from a positioning system. The digital satellite radio system broadcasts the aiding information in the data signals it broadcasts to its subscribers. The subscribers receive the aiding information at satellite radio receivers and communicate the aiding information to the SPS receiver. The data signals may also be communicated to terrestrial repeaters for re-broadcast at a higher power. The terrestrial repeaters may input a transmitter identifier to permit the satellite radio receiver to determine a geographical location of the terrestrial repeater as its own.
    Type: Grant
    Filed: October 30, 2006
    Date of Patent: May 18, 2010
    Assignee: SiRF Technology, Inc.
    Inventors: Ashutosh Pande, Steve Chang, Lars Boeryd
  • Publication number: 20100115379
    Abstract: Systems, devices, and methods for error detection and correction in digital communication are disclosed. One such method comprises: storing data received in TS packets into an MPE-FEC frame buffer of a receiver according to locations indicated by an MPE-FEC frame buffer write pointer; and storing reliability information regarding said data separately therefrom, said reliability information including addresses of one or more locations in said MPE-FEC frame buffer to be marked for erasure. One such device is a receiver comprising an MPE-FEC frame buffer and an FEC decoder. The FEC decoder is configured to store data received in TS packets into the MPE-FEC buffer according to locations indicated by an MPE-FEC frame buffer write pointer. The FEC decoder is further configured to store reliability information regarding the data separately therefrom, the reliability information including addresses of one or more locations in the MPE-FEC frame buffer to be marked for erasure.
    Type: Application
    Filed: November 5, 2009
    Publication date: May 6, 2010
    Applicant: SIRF TECHNOLOGY, INC.
    Inventors: Rajugopal Gubbi, Ramanujan Valmiki
  • Patent number: 7711038
    Abstract: Implementation of an improved matched filter system for despreading a PN code from a spread spectrum signal utilizes a matched filter system that may be broadly conceptualized as a system that optimizes the number of multipliers and adders utilized by the system in despreading a PN code from a spread spectrum signal. This lowers the power consumption of the improved matched filter system and increases the speed at which the system despreads the PN code from the spread spectrum signal.
    Type: Grant
    Filed: June 27, 2000
    Date of Patent: May 4, 2010
    Assignee: SiRF Technology, Inc.
    Inventors: Paul A. Underbrink, Steven A. Gronemyer
  • Patent number: 7711483
    Abstract: In one embodiment, a system and method of dead reckoning navigation for a vehicle uses a set of accelerometers. Sensed accelerometers from the set are converted into a vehicle body frame of reference set of accelerations. The resulting converted accelerations are then used to determine a dead-reckoning longitudinal acceleration for the vehicle. By integrating the longitudinal acceleration along a heading for the vehicle, a dead-reckoning-determined location for the vehicle is provided.
    Type: Grant
    Filed: September 14, 2006
    Date of Patent: May 4, 2010
    Assignee: SiRF Technology, Inc.
    Inventor: Jaime B. Colley
  • Patent number: 7702040
    Abstract: An embodiment and method of the present invention includes a frequency lock loop (FLL) having an improved frequency error estimation and a low bit error rate (BER) in data demodulation by calculating and using an improved averaged phase rotation using ‘valid’ phase rotation samples.
    Type: Grant
    Filed: April 12, 2006
    Date of Patent: April 20, 2010
    Assignee: SiRF Technology, Inc.
    Inventors: Xiang Yuan, Gang Xie
  • Patent number: 7680178
    Abstract: A communication device with cross-correlation detection based upon statistical tests to determine whether the off-peak signal energy is consistent with auto-correlation energy levels.
    Type: Grant
    Filed: December 7, 2005
    Date of Patent: March 16, 2010
    Assignee: SIRF Technology, Inc.
    Inventors: Sundar Raman, Reza Abtahi, Steven A. Gronemeyer, Andrew Chou
  • Patent number: 7679557
    Abstract: Multifunction satellite positioning receiver having a plurality of functions that are selectable in response to predetermined events or in response to user actions and enable more efficient use of the hardware and processing resources of a multifunction satellite position receiver.
    Type: Grant
    Filed: December 14, 2006
    Date of Patent: March 16, 2010
    Assignee: SiRF Technology, Inc.
    Inventor: Ashutosh Pande
  • Patent number: 7680223
    Abstract: A method for detecting a positioning signal includes (a) correlating a segment of a received positioning signal with a reference signal of a selected code phase and frequency to obtain a correlation value, (b) if the correlation value is less than a predetermined minimum, assigning the correlation value to the predetermined minimum, and (c) accumulating the correlation value in a sum of correlation values obtained using other segments of the received positioning signal. In addition, the correlation value may be reduced by a predetermined value, which is preferably an expected mean value for a noise component in the segment of the received positioning signal.
    Type: Grant
    Filed: December 21, 2007
    Date of Patent: March 16, 2010
    Assignee: SirF Technology, Inc.
    Inventors: Julien Basch, Andrew Chou, Robert Lorenz, Jesse Stone
  • Patent number: 7672675
    Abstract: A system is described that utilizes the measured characteristics of a cell site or a plurality of cell sites (100, 102, 104) and the cellular identification to selectively provide a wireless device (118) with location aiding from a cellular network server (120). The system may include a basestation (106, 108, 110) located within the cell site, a cellular measurement unit located in the wireless device (118), and a database (214) containing positional assistance information corresponding to the characteristic information. The system may also include a processing unit in signal communication with the basestation and the database (214) and a positional determination unit in the wireless device (118).
    Type: Grant
    Filed: September 10, 2002
    Date of Patent: March 2, 2010
    Assignee: SiRF Technology Inc.
    Inventors: Ashutosh Pande, Lionel Jacques Garin
  • Patent number: 7672361
    Abstract: Implementation of an improved matched filter system for despreading a PN code from a spread spectrum signal utilizes a matched filter system that may be broadly conceptualized as a system that optimizes the number of multipliers and adders utilized by the system in despreading a PN code from a spread spectrum signal. This lowers the power consumption of the improved matched filter system and increases the speed at which the system despreads the PN code from the spread spectrum signal.
    Type: Grant
    Filed: June 16, 2004
    Date of Patent: March 2, 2010
    Assignee: SiRF Technology Inc.
    Inventors: Paul A. Underbrink, Steven A. Gronemyer
  • Patent number: 7671489
    Abstract: A method and apparatus for detecting the presence of a specified voltage source and automatically switching off a second voltage source regardless of voltage source potential of the two voltage sources are disclosed. The present invention uses pinch-off of a JFET, controlled by an inverter, to control a backup power supply based on the availability of the main supply.
    Type: Grant
    Filed: January 17, 2002
    Date of Patent: March 2, 2010
    Assignee: SIRF Technology, Inc.
    Inventors: Allan Paul T. Uy, Richard Joseph McConnell
  • Patent number: 7671672
    Abstract: An active circuit includes (a) a first chopper circuit that receives an input signal and a chopping signal of a frequency higher than a base band of the input signal, and that provides a modulated input signal; (b) an amplifier that receives the modulated input signal and that provides an amplified signal resulting from amplifying the modulated input signal; and (c) a second chopper circuit that receives the amplified signal and the chopping signal to provide an output signal. The chopping signal has a frequency that may be dynamically adjusted to accommodate changes in impedance and signal spectrum as a result of the operations of the chopper circuits. The active circuit further includes a low pass filter that receives the output signal and that attenuates components of the output signal above the base band of the input signal. In this manner 1/f noise introduced by the amplifier is eliminated or reduced.
    Type: Grant
    Filed: December 22, 2006
    Date of Patent: March 2, 2010
    Assignee: SiRF Technology, Inc.
    Inventor: Richard McConnell
  • Patent number: 7668554
    Abstract: A network approach for aided GPS broadcast positioning where A-GPS data is made available in the network and broadcast via cell broadcast servers to wireless devices in order to reduce the time required to determine the position of a wireless device.
    Type: Grant
    Filed: December 16, 2005
    Date of Patent: February 23, 2010
    Assignee: SiRF Technology, Inc.
    Inventor: Steve Chang
  • Publication number: 20100039316
    Abstract: A wireless device including a transceiver that utilizes a power supply is described. The wireless device includes a Global Positioning System (“GPS”) section having a plurality of GPS subsystems and a power controller in signal communication with the power supply and GPS section, wherein the power controller is configured to selectively power each GPS subsystem from the plurality of GPS subsystems.
    Type: Application
    Filed: March 30, 2009
    Publication date: February 18, 2010
    Applicant: SiRF Technology, Inc.
    Inventors: Steven A. Gronemeyer, Sanjai Kohli, Mark A. Sturza, Don K. Leimer
  • Patent number: 7664206
    Abstract: A radio frequency integrated circuit for a global positioning system (GPS) application mixes radio frequency GPS signals from an external source with a predetermined intermediate frequency that is less than 4fo. In one embodiment, the intermediate frequency is selected to be 1.5fo. An intermediate frequency filter then band-limits the intermediate frequency GPS signals, rolling off at a frequency in the vicinity of 2.5 MHz to achieve substantial attenuation at 3.5-4.0 MHz. An automatic gain control circuit amplifies the filtered intermediate frequency GPS signals to proper voltage levels. The amplified intermediate frequency GPS signals is then digitized by an analog-to-digital converter at a predetermined sampling rate more than twice the intermediate frequency to provide samples of a predetermined number of bits, which are then provided for base band processing by a general purpose microprocessor over an industry-standard serial bus.
    Type: Grant
    Filed: July 29, 2005
    Date of Patent: February 16, 2010
    Assignee: SiRF Technology, Inc.
    Inventors: Erik Anderson, Daniel Babitch, Majid Hashemi
  • Patent number: 7664187
    Abstract: An input random access memory (RAM) module of a fast Fourier transform (FFT) engine of a DVB receiver is used to store, during a first time period, delayed versions of an input signal that includes a first orthogonal frequency division multiplexed (OFDM) symbol and a cyclic prefix therefor received at the receiver, and samples for a second OFDM symbol to be demodulated using the FFT engine during a second time period. Delayed versions of the input signal are stored in the input RAM module of the FFT engine in a first-in-first-out (FIFO) fashion for signal acquisition and for FFT processing. Similarly, an output RAM module of the FFT engine is used to store moving averages of an autocorrelation of the input signal with its cyclic prefix computed over presumed guard intervals and over multiple symbols.
    Type: Grant
    Filed: April 22, 2006
    Date of Patent: February 16, 2010
    Assignee: SiRF Technology, Inc.
    Inventors: Steven Chen, Howard K. Luu