Patents by Inventor Douglas W. Friedrich

Douglas W. Friedrich 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: 5629855
    Abstract: Systems and methods allow for the accurate determination of the terrestrial position of an autonomous vehicle in real time. A first position estimate of the vehicle 102 is derived from satellites of a global positioning system and/or a pseudolite(s). The pseudolite(s) may be used exclusively when the satellites are not in the view of the vehicle. A second position estimate is derived from an inertial reference unit and/or a vehicle odometer. The first and second position estimates are combined and filtered using novel techniques to derive a more accurate third position estimate of the vehicle's position. Accordingly, accurate autonomous navigation of the vehicle can be effectuated using the third position estimate.
    Type: Grant
    Filed: June 1, 1995
    Date of Patent: May 13, 1997
    Assignee: Caterpillar Inc.
    Inventors: Christos T. Kyrtsos, James W. Sennott, Adam J. Gudat, Dana A. Christensen, Douglas W. Friedrich, Darrell E. Stafford
  • Patent number: 5555503
    Abstract: A vehicle position determination system and method provide accurate vehicle positioning using a global positioning system. Spatial bias techniques are used to improve positioning accuracy while the vehicle is in the midst of a relatively linear path and is not approaching a drastically nonlinear path. The use of spatial bias techniques is suspended while the vehicle is approaching or in a drastically nonlinear path.
    Type: Grant
    Filed: November 23, 1993
    Date of Patent: September 10, 1996
    Assignee: Caterpillar Inc.
    Inventors: Christos T. Kyrtsos, Adam J. Gudat, Dana A. Christensen, Douglas W. Friedrich, Darrell E. Stafford
  • Patent number: 5438517
    Abstract: Systems and methods allow for the accurate determination of the terrestrial position of an autonomous vehicle in real time. A first position estimate of the vehicle 102 is derived from satellites of a global positioning system and/or a pseudolite(s). The pseudolite(s) may be used exclusively when the satellites are not in the view of the vehicle. A second position estimate is derived from an inertial reference unit and/or a vehicle odometer. The first and second position estimates are combined and filtered using novel techniques to derive a more accurate third position estimate of the vehicle's position. Accordingly, accurate autonomous navigation of the vehicle can be effectuated using the third position estimate.
    Type: Grant
    Filed: February 18, 1993
    Date of Patent: August 1, 1995
    Assignee: Caterpillar Inc.
    Inventors: James W. Sennott, Christos T. Kyrtsos, Adam J. Gudat, Dana A. Christensen, Douglas W. Friedrich, Darrell E. Stafford
  • Patent number: 5410325
    Abstract: An apparatus for mounting an antenna assembly to an elevationally movable portion of a vehicle dump bed includes a mountable support member having first and second end portions. The first end portion is fixed to the vehicle bed. The antenna assembly has an active element connected to a first end of a mounting element and a counterweight element connected to a second end of a mounting element. An intermediate portion of the mounting element is connected to the second end portion of the mountable support member. The antenna assembly is therefore free to rotate about at least one axis parallel to the axis of rotation of the elevationally movable dump bed.
    Type: Grant
    Filed: August 9, 1993
    Date of Patent: April 25, 1995
    Assignee: Caterpillar Inc.
    Inventors: Douglas W. Friedrich, Carl A. Kemner, N. Keith Lay, Joel L. Peterson
  • Patent number: 5390125
    Abstract: Systems and methods allow for the accurate determination of the terrestrial position of an autonomous vehicle in real time. A first position estimate of the vehicle 102 is derived from satellites of a global positioning system and/or a pseudolite(s). The pseudolite(s) may be used exclusively when the satellites are not in the view of the vehicle. A second position estimate is derived from an inertial reference unit and/or a vehicle odometer. The first and second position estimates are combined and filtered using novel techniques to derive a more accurate third position estimate of the vehicle's position. Accordingly, accurate autonomous navigation of the vehicle can be effectuated using the third position estimate.
    Type: Grant
    Filed: February 18, 1993
    Date of Patent: February 14, 1995
    Assignee: Caterpillar Inc.
    Inventors: James W. Sennott, Christos T. Kyrtsos, Adam J. Gudat, Dana A. Christensen, Douglas W. Friedrich, Darrell E. Stafford
  • Patent number: 5375059
    Abstract: Systems and methods allow for the accurate determination of the terrestrial position of an autonomous vehicle in real time. A first position estimate of the vehicle 102 is derived from satellites of a global positioning system and/or a pseudolite(s). The pseudolite(s) may be used exclusively when the satellites are not in the view of the vehicle. A second position estimate is derived from an inertial reference unit and/or a vehicle odometer. The first and second position estimates are combined and filtered using novel techniques to derive a more accurate third position estimate of the vehicle's position. Accordingly, accurate autonomous navigation of the vehicle can be effectuated using the third position estimate.
    Type: Grant
    Filed: February 18, 1993
    Date of Patent: December 20, 1994
    Assignee: Caterpillar Inc.
    Inventors: Christos T. Kyrtsos, Adam J. Gudat, Dana A. Christensen, Douglas W. Friedrich, Darrell E. Stafford
  • Patent number: 5359521
    Abstract: An apparatus and method for determining the position of a vehicle relative to the center of the Earth uses navigation signals from a satellite based navigation system which includes a plurality of satellites orbiting the Earth. In one embodiment, a plurality of antennas are mounted on the vehicle. The distance between the antennas is precisely known. This distance is used to constrain the solution of a vehicle position estimate to improve the accuracy of the position estimate. In another embodiment, a plurality of receiver systems are used in place of the plurality of antennas. In yet another embodiment, a plurality of base stations with known positions are used to constrain the solution of the vehicle position estimate.
    Type: Grant
    Filed: December 1, 1992
    Date of Patent: October 25, 1994
    Assignee: Caterpillar Inc.
    Inventors: Christos T. Kyrtsos, Adam J. Gudat, Douglas W. Friedrich