Patents Assigned to SIRF Technology
  • Patent number: 7953142
    Abstract: A variable code-tracking loop filter in a receiver having the ability to change its parameters multiple times in response to received signals. Parameters for the code-tracking loop filter may be varied based on phase and frequency errors from an error detector. In one implementation, the code-tracking loop filter is able to repeatedly vary a single parameter, such as its received bandwidth, based on the phase and frequency errors, while in another, the code-tracking loop filter may vary two or more parameters, such as the loop bandwidth and the natural frequency.
    Type: Grant
    Filed: October 17, 2002
    Date of Patent: May 31, 2011
    Assignee: Sirf Technology
    Inventor: Mangesh Chansarkar
  • Patent number: 7855608
    Abstract: A system and method for providing temperature compensation in a oscillator component (such as a crystal oscillator component) that includes a closely-located temperature sensing device. The crystal oscillator component in example systems and methods is exposed to a temperature profile during a calibration procedure. Temperature and frequency data are collected and applied to coefficient generating function according to a temperature compensation model to generate a set of coefficients that are used in the temperature compensation model in an application device. The generated coefficients are stored in a coefficient memory accessible to an application device during operation.
    Type: Grant
    Filed: December 9, 2008
    Date of Patent: December 21, 2010
    Assignee: SiRF Technology
    Inventor: Daniel Babitch
  • Patent number: 7724807
    Abstract: The present invention discloses methods, apparatuses, and systems for eliminating auto- and cross-correlation in weak signal CDMA systems, such as GPS systems. The invention uses parallel data paths that allow standard correlation of signals in parallel with verification of the lock signal to determine whether the system has locked onto the proper signal within the scanned signal window. The invention can be made with multiple CPUs, a single CPU with dual input modes, on multiple IC chips, or as a single IC chip solution for small, low cost reception, downconversion, correlation, and verification systems.
    Type: Grant
    Filed: August 2, 2006
    Date of Patent: May 25, 2010
    Assignee: SiRF Technology
    Inventors: Gregory Bret Turetzky, Charles P. Norman, Henry D. Falk
  • Patent number: 7710318
    Abstract: The present invention provides systems and methods for reducing the ‘cold start’ TTFF of navigation receivers. The systems and methods receive geographical information from a user, such as the nearest city, state or country, and use this geographical information to approximate the position of the receiver. The systems and methods then make use of the approximate position to reduce the ‘cold start’ TTFF. In an embodiment, the approximate position of the receiver is determined from a co-ordinate database in the receiver based on the geographical information provided by the user. In another embodiment, a user provides geographical information to the receiver through a displayed map with several stages of zooming capability.
    Type: Grant
    Filed: August 24, 2006
    Date of Patent: May 4, 2010
    Assignee: SIRF Technology
    Inventors: David Wang, Henry Leung
  • 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