Navigational aid
First Claim
1. Apparatus for determining the attitude of a body operating in a gravitational field comprising:
- acceleration sensor means for measuring the total acceleration of the body in relation to a coordinate system fixed with respect to said body;
inertial acceleration calculating means for calculating the total inertial component of the total acceleration in relation to said coordinate system;
comparator means for comparing said measured total acceleration with said total inertial component thereby to generate data representative of the orientation of the gravitational component of acceleration in relation to said coordinate system; and
attitude calculating means for receiving said data and for calculating the attitude of the body.
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Accused Products
Abstract
An aircraft operating in a gravitational field and having conventional sensors for measuring true air speed (sensors 10, 11), angles of incidence and yaw (sensors 13, 12), rotation about x, y and z axes and acceleration therealong (sensors 14, 15, 16) is provided with means for calculating the inertial component of the acceleration from data concerning the true air speed, heading and rotation of the aircraft obtained from the sensors, and means for comparing the inertial component with the total acceleration sensed, thereby to deduce the orientation of the gravitational component and hence obtain an estimate of the pitch and bank angles of the aircraft.
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Citations
11 Claims
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1. Apparatus for determining the attitude of a body operating in a gravitational field comprising:
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acceleration sensor means for measuring the total acceleration of the body in relation to a coordinate system fixed with respect to said body; inertial acceleration calculating means for calculating the total inertial component of the total acceleration in relation to said coordinate system; comparator means for comparing said measured total acceleration with said total inertial component thereby to generate data representative of the orientation of the gravitational component of acceleration in relation to said coordinate system; and attitude calculating means for receiving said data and for calculating the attitude of the body.
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2. A method of determining the attitude of a body operating in a gravitational field comprising:
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measuring the total acceleration acting on the body in relation to a coordinate system fixed with respect to said body; calculating the total inertial component of the total acceleration in relation to said coordinate system; comparing said measured total acceleration with said total inertial component, thereby to generate data representative of the orientation of the gravitational component of acceleration in relation to said coordinate system; and processing said data to determine the attitude of said body.
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3. An arrangement for determining the attitude of a body operating in a gravitational field comprising:
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means for defining, with respect to said body, a coordinate system having three orthogonal axes; velocity sensor means for sensing body velocity magnitude and direction relative to said axes; rotation sensor means for sensing rotation of the body about each of said axes; acceleration sensor means for measuring the total acceleration of the body along each of said axes; inertial acceleration calculating means for receiving data from said velocity sensor means and said rotation sensor means and processing it to determine the total inertial component of acceleration of the body; comparator means for comparing said measured total acceleration with said total inertia component thereby to generate data representative of the orientation of the gravitational component of acceleration in relation to said coordinate system; and attitude calculating means for receiving said data and for calculating the attitude of the body. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10)
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11. Apparatus for determining the attitude of the body operating in a gravitational field comprising:
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acceleration sensor means for measuring the total acceleration of the body in relation to a coordinated system fixed with respect to said body and for outputting data (xm, ym, zm) representative of said measured total acceleration; inertial acceleration calculating means for calculating the total inertial component of the total acceleration in relation to said coordinate system and for outputting data (xi, yi, zi) representative of said total inertial component; and attitude calculating means for receiving data output by said inertial acceleration calculating means and for processing it to determine the pitch and bank angles of the body (θ
, φ
) according to the following expressions;
space="preserve" listing-type="equation">θ
=arcsin [x.sub.m -x.sub.i)/g]
space="preserve" listing-type="equation">φ
=arctan [y.sub.m -y.sub.i)/(z.sub.m -z.sub.i)].
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Specification