Patents by Inventor John J James

John J James 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: 8755161
    Abstract: An overvoltage protection circuit is based on replacing the bias resistor in a conventional overvoltage protection circuit with a self-biased latch. The new circuit automatically survives both overvoltage and overcurrent events.
    Type: Grant
    Filed: June 28, 2012
    Date of Patent: June 17, 2014
    Assignee: Trimble Navigation Limited
    Inventor: John J James
  • Publication number: 20140002941
    Abstract: An overvoltage protection circuit is based on replacing the bias resistor in a conventional overvoltage protection circuit with a self-biased latch. The new circuit automatically survives both overvoltage and overcurrent events.
    Type: Application
    Filed: June 28, 2012
    Publication date: January 2, 2014
    Applicant: TRIMBLE NAVIGATION LIMITED
    Inventor: John J. James
  • Patent number: 8521428
    Abstract: A system and method for more accurately and robustly determining the heading of a vehicle by taking measurements of angle rates using rate sensors mounted on a movable mechanical assembly. In a quasi-static state of the vehicle, the mechanical assembly is rotated around axes perpendicular to the tangent plane of the Earth, and angle rates are measured by the rate sensors at different rotational angles of the mechanical assembly. The measurements of the angle rates are then computed to determine the initial heading of the vehicle relative to the true north of the Earth in the quasi-static state of the vehicle. After determining the initial heading, navigation state propagation is performed to determine the heading of the vehicle in non-quasi-static state of the vehicle. By taking measurements of the rate sensors at different rotation angles and performing computation, the heading of the vehicle relative to the Earth's true north can be determined using less accurate angle sensors.
    Type: Grant
    Filed: October 15, 2009
    Date of Patent: August 27, 2013
    Assignee: Moog Inc.
    Inventors: Darren S. Liccardo, John J. James, Walter K. Stockwell, Michael A. Horton
  • Patent number: 7755349
    Abstract: Method and apparatus improve sensing accuracy and reduce bias shift in anisotropic magneto-resistive sensors using paired integrators and sampling switches for processing outputs of the sensor on applied set and reset signals with high immunity to temperature variations.
    Type: Grant
    Filed: March 3, 2008
    Date of Patent: July 13, 2010
    Assignee: MEMSIC, Inc.
    Inventor: John J James
  • Publication number: 20090219011
    Abstract: Method and apparatus improve sensing accuracy and reduce bias shift in anisotropic magneto-resistive sensors using paired integrators and sampling switches for processing outputs of the sensor on applied set and reset signals with high immunity to temperature variations.
    Type: Application
    Filed: March 3, 2008
    Publication date: September 3, 2009
    Applicant: CROSSBOW TECHNOLOGY, INC.
    Inventor: John J. James
  • Patent number: 6084406
    Abstract: A magnetic field sensor element comprises an elongated core of high-magnetic permeability material having a coil of electrically-conductive wire wound around and along a central axis of the core. The sensor, due to inductance of the core which changes with application of a local magnetic field, exhibits a characteristic of delaying an electrical input as a function of the strength of a magnetic field in the direction of the axis of the core, and the delay is measured as a function of the strength of the magnetic field. Appropriate circuitry provides at least one step-function voltage input to the coil such that the resulting delay in current charge-up into the coil creates a voltage across the coil which decays to a known reference value. The time delay for the voltage decaying to the reference value varies as a monotonic function with the strength of the applied magnetic field to be measured.
    Type: Grant
    Filed: April 1, 1997
    Date of Patent: July 4, 2000
    Assignee: Precision Navigation, Inc.
    Inventors: John J. James, George Hsu
  • Patent number: 5680708
    Abstract: A new tilt sensor system is disclosed which provides substantial temperature independence and is very inexpensive to build and to operate. The apparatus is made up of a first source of a first alternating signal having an output impedance Rs1 and a second source of a second alternating signal which is equal in magnitude and 180 degrees out of phase with the first alternating signal, with the source of the second alternating signal having an output impedance Rs2. Also included is a tilt sensor having a first input terminal coupled to receive the first alternating signal, a second input terminal coupled to receive the second alternating signal, and an output terminal which provides an output signal in response to the first alternating signal and the second alternating signal. In the preferred mode, the tilt sensor has an impedance G1 between the first terminal and the output terminal and an impedance G2 between the second terminal and the output terminal.
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: October 28, 1997
    Assignee: Precision Navigation, Inc.
    Inventor: John J. James