Self-aligning pitch and azimuth reference unit
First Claim
1. A system for determining orientation or position comprising:
- movable means having a principal direction of interest;
an instrument assembly including an accelerometer having its sensitive axis aligned with said principal direction and a two-degree-of-freedom gyro having its spin axis fixedly aligned with the sensitive axis of said accelerometer; and
support means for pendulously mounting said instrument assembly to said movable means for pendulous rotation only about an axis aligned with said principal direction of interest.
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Accused Products
Abstract
A system for determining orientation or position of a movable supporting structure, such as a vehicle, includes a special inertial sensor unit. This unit includes a single gyroscope hereinafter referred to as a "gyro", with its spin axis mounted in alignment with the sensitive axis of an accelerometer. The gyro and accelerometer are mounted pendulously to rotate only about a single axis which is aligned with a direction of travel of the vehicle or with a projectile launching assembly. In additon to being pendulously mounted as mentioned above, the gyro and accelerometer combination may be rotated relative to their pendulous support, to certain fixed positions, in order to facilitate rapid initial alignment and orientation and pre-mission calibration of the inertial instruments. The pendulously mounted unit is also provided with an optical encoder to indicate the roll angle of the vehicle to which the inertial unit is secured.
In an initial rapid alignment sequence after the unit is energized, the rotation of the earth is sensed and the information stored with the unit in two or three different orientations, and, using this stored information, and the stored accelerometer outputs, the azimuth of the pendulous axis relative to true north and its pitch or elevation angle may be accurately determined.
When mounted in a vehicle and used in combination with the output from the vehicle odometer, an accurate indication of the movement of the vehicle may be obtained, and when combined with initial position and orientation data, the position of the vehicle may be continuously determined.
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Citations
12 Claims
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1. A system for determining orientation or position comprising:
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movable means having a principal direction of interest; an instrument assembly including an accelerometer having its sensitive axis aligned with said principal direction and a two-degree-of-freedom gyro having its spin axis fixedly aligned with the sensitive axis of said accelerometer; and support means for pendulously mounting said instrument assembly to said movable means for pendulous rotation only about an axis aligned with said principal direction of interest. - View Dependent Claims (2, 3, 4)
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5. A system for determining orientation or position comprising:
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a projectile launching assembly having a principal direction of interest in the direction in which projectiles are to be launched; an instrument assembly including an accelerometer having its sensitive axis aligned with said principal direction and a two degree of freedom gyro having its spin axis fixedly aligned with the sensitive axis of said accelerometer; and support means for pendulously mounting said instrument assembly to said projectile launching assembly for pendulous rotation only about an axis aligned with said principal direction of interest. - View Dependent Claims (6)
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7. A system for determining orientation or position comprising:
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movable means having a principal direction of interest; an instrument assembly consisting solely of an accelerometer having its sensitive axis aligned with said principal direction, and a two degree of freedom gyro having its spin axis fixedly aligned with the sensitive axis of said accelerometer; and support means for pendulously mounting said assembly to said movable means for pendulous rotation only about an axis aligned with said principal direction of interest. - View Dependent Claims (9)
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8. A system for determining orientation or position comprising:
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movable means having a principal direction of interest; an instrument assembly including an accelerometer having a sensitive axis and a two degree of freedom gyro having its spin axis fixedly aligned with the sensitive axis of said accelerometer; support means for pendulously mounting said assembly to said movable means for pendulous rotation only about an axis aligned with said principal direction of interest, with the spin axis of the said gyro and the sensitive axis of the said accelerometer aligned with said principal direction of interest; and means for mechanically rotating said gyro and accelerometer successively to a plurality of fixed discrete angular positions about an axis perpendicular to said principal direction of interest.
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10. A system for determining orientation or position comprising:
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a vehicle having a principal direction of interest in the direction of the front-to-rear axis of motion of said vehicle; an instrument assembly including an accelerometer having its sensitive axis aligned with said principal direction and a two degree of freedom gyro having a spin axis fixedly aligned with the sensitive axis of said accelerometer; support means for pendulously mounting said assembly to said movable means for pendulous rotation only about an axis aligned with said principal direction of interest; odometer means operatively mounted in said vehicle of indicating forward movement of said vehicle; and means for receiving data from said gyro, said accelerometer and said odometer for indicating the position of said vehicle. - View Dependent Claims (11, 12)
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Specification