Patents Assigned to Tech-21 Limited
  • Method and apparatus for providing a magnetic direction reference
    Patent number: 6227310
    Abstract: A magnetic observatory device is deployed at a fixed location such as the sea bed to provide data measuring variations in the local earth magnetic field. This data is used to correct information from magnetic direction sensors, for example in a measurement-while-drilling system of a drill string. Also described is a reference apparatus for initial calibration of the device or for marine magnetic mapping purposes.
    Type: Grant
    Filed: June 10, 1999
    Date of Patent: May 8, 2001
    Assignee: Tech-21 Limited
    Inventor: Angus Lamberton Jamieson