Patents by Inventor Edmund H. Christy

Edmund H. Christy 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).

  • High frequency spread spectrum positioning system and method therefor
    Patent number: 4665404
    Abstract: The system includes a method and apparatus for transmitting a spread spectrum signal from each of a plurality of base stations. The spread spectrum signal has a predetermined timing and has a ground wave component and a sky wave component. The signal is transmitted with a repetition time at least as great as a maximum anticipated delay time of the sky wave component such that the ground wave component of the transmitted spread spectrum signal can be distinguished from the sky wave component. The signal is detected at each of a plurality of mobile stations and the timing of the detected signal is compared to a local timing signal. The phase difference between these signals is indicative of the range of the base station from the mobile station.
    Type: Grant
    Filed: October 19, 1984
    Date of Patent: May 12, 1987
    Assignee: Offshore Navigation, Inc.
    Inventors: Edmund H. Christy, Robert E. Rouquette, Lawrence Van Doren