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Method and apparatus for determining direction of the beginning of vehicle movement

  • US 9,534,898 B2
  • Filed: 10/26/2010
  • Issued: 01/03/2017
  • Est. Priority Date: 06/16/2010
  • Status: Active Grant
First Claim
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1. A method for determining whether a moving vehicle is moving in a forward movement mode or in a backward movement mode, the method comprising the steps of:

  • measuring a compass azimuthal angle of the moving vehicle, wherein;

    the compass azimuthal angle is measured with a compass mounted on the moving vehicle; and

    the compass azimuthal angle is referenced to a first North axis;

    transmitting, from the compass, the compass azimuthal angle;

    measuring, at a first time, a first vehicle distance and a first vehicle azimuthal angle, wherein;

    the first vehicle distance and the first vehicle azimuthal angle are measured with a movement measurement unit;

    the movement measurement unit comprises;

    a range finder and an angle meter mounted at a ground location outside of the moving vehicle; and

    a marker mounted on the moving vehicle;

    the first vehicle distance is measured between the ground location outside of the moving vehicle and the marker mounted on the moving vehicle; and

    the first vehicle azimuthal angle is measured about the ground location outside of the moving vehicle from a second North axis to the marker mounted on the moving vehicle;

    measuring, at a second time, a second vehicle distance and a second vehicle azimuthal angle, wherein;

    the second vehicle distance and the second vehicle azimuthal angle are measured with the movement measurement unit;

    the second vehicle distance is measured between the ground location outside of the moving vehicle and the marker mounted on the moving vehicle; and

    the second vehicle azimuthal angle is measured about the ground location outside of the moving vehicle from the second North axis to the marker mounted on the moving vehicle;

    transmitting, from the movement measurement unit, the first vehicle distance, the first vehicle azimuthal angle, the second vehicle distance, and the second vehicle azimuthal angle;

    receiving, at a computation unit, the compass azimuthal angle, the first vehicle distance, the first vehicle azimuthal angle, the second vehicle distance, and the second vehicle azimuthal angle;

    computing, with the computation unit, a movement vector azimuthal angle of the moving vehicle, wherein;

    the movement vector azimuthal angle is based at least in part on the first vehicle distance, the first vehicle azimuthal angle, the second vehicle distance, and the second vehicle azimuthal angle; and

    the movement vector azimuthal angle is referenced to the second North axis; and

    determining, with the computation unit, whether the moving vehicle is moving in the forward movement mode or in the backward movement mode based at least in part on the compass azimuthal angle and the movement vector azimuthal angle; and

    wherein;

    the compass is oriented such that, when the moving vehicle is moving along the first North axis in the forward movement mode, the compass azimuthal angle is zero; and

    the step of determining, with the computation unit, whether the moving vehicle is moving in the forward movement mode or in the backward movement mode comprises the steps of;

    computing an angle based at least in part on a difference between the compass azimuthal angle and the movement vector azimuthal angle;

    computing an absolute value of the angle;

    comparing the absolute value to 90 degrees;

    upon determining that the absolute value is greater than 90 degrees, determining that the moving vehicle is moving in the backward movement mode; and

    upon determining that the absolute value is not greater than 90 degrees, determining that the moving vehicle is moving in the forward movement mode.

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