Magnetic compass
First Claim
1. An electronic magnetic compass system for determining the heading of a portion of a heavily armored vehicle, comprising in combination:
- a biaxial fluxgate magnetometer positioned in an antenna-like structure in a position above a highest level of the vehicle for determining magnetic field components with respect to the vehicle;
two inclinometers for determining pitch and tilt angles of the vehicle with respect to a horizontal plane;
computing means for geometric correction of the magnetic field components dependent on the pitch and tilt angles, for determining iron body perturbation of the local magnetic field of the earth due to one or more rotational prolate ferromagnetic ellipsoids of predetermined dimensions and position relative to each other, representing iron body portions of said vehicle, for perturbation correction of the magnetic field components, and for determining the heading of a portion of the vehicle dependent on the geometric and perturbation corrections.
1 Assignment
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Accused Products
Abstract
An electronic compass system for determining the heading of an armored vehicle containing a large mass of ferromagnetic material, which system comprises a plurality of sensors, and for real-time computation of the corrections required of actual magnetometer measurements. Part of the values used for the computation are computed in advance, and part in real-time. Some of the computations are based on the perturbation of the earth magnetic field based on an algorithm which takes into account one or two rotational prolate ferromagnetic ellipsoids which have certain dimensions and which are at a predetermined distance from each other either represent the body of an armored vehicle, or when two ellipsoids are used, they represent the hull and turret of a tank.
31 Citations
12 Claims
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1. An electronic magnetic compass system for determining the heading of a portion of a heavily armored vehicle, comprising in combination:
- a biaxial fluxgate magnetometer positioned in an antenna-like structure in a position above a highest level of the vehicle for determining magnetic field components with respect to the vehicle;
two inclinometers for determining pitch and tilt angles of the vehicle with respect to a horizontal plane;
computing means for geometric correction of the magnetic field components dependent on the pitch and tilt angles, for determining iron body perturbation of the local magnetic field of the earth due to one or more rotational prolate ferromagnetic ellipsoids of predetermined dimensions and position relative to each other, representing iron body portions of said vehicle, for perturbation correction of the magnetic field components, and for determining the heading of a portion of the vehicle dependent on the geometric and perturbation corrections. - View Dependent Claims (2, 3, 4, 5, 6, 7, 9, 10, 12)
- a biaxial fluxgate magnetometer positioned in an antenna-like structure in a position above a highest level of the vehicle for determining magnetic field components with respect to the vehicle;
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8. A system for measurement with adequate accuracy the heading of a heavily armored vehicle by compass means, by correcting magnetic perturbations due to residual and temporary magnetization of the body of such vehicle, which system comprises:
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a biaxial fluxgate magnetometer on the vehicle in a position selected to optimize correction of flux measurement signals generated by the magnetometer; pendulum-type inclinometers for outputting electrical measurement signals corresponding to inclination angles of the vehicle with respect to horizontal plane; an A/D+MUX card for receiving and processing such measurement signals; a microprocessor based unit communicating with such card for real time signal corrections; a non-volatile memory apparatus communicating with the microprocessor to direct microprocessor function based on models within the memory representing mathematical procedures; control and display panels in the vehicle for displaying signals output from the microprocessor; interconnecting cables between the above parts, and in which the memory includes a model of one or more prolate ferromagnetic ellipsoids of predetermined size and position relative to each other representing respective portions of the vehicle to direct the microprocessor to correct signals input from the card to generate corrected signals output to the panels. - View Dependent Claims (11)
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Specification