System and method of detecting the proximity of an alternating magnetic field
AssigneeSperry Corporation
InventorsDavid G. Young, Peter D. Finch
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Abstract
A system for, and a method of, detecting the proximity of a source of an alternating magnetic field, such as that emanating from power transmission cables, comprising a sensor coil sensitive to the magnetic field under detection, processing means to derive from the signal induced in the coil a warning signal indicative of the proximity of the magnetic field under detection, and cancelling means operable to cancel the earth's field in the region of the sensor coil. The sensor coil may be one of a pair operable to provide a signal representative of the directional heading of the magnetic field under detection, with respect to the system, which embodiment is particularly useful in helicopters for detecting the proximity of power cables.
Claims10
A system for detecting the proximity of a source of an alternating magnetic field, said magnetic field having a horizontal component with a horizontal magnitude and a vertical component with a vertical magnitude comprising:
- sensor means including first and second sensor coils, mounted in respective generally vertical non-parallel planes, each substantially responsive to said horizontal component of said alternating magnetic field for respectively producing first and second signals;
- processing means coupled to receive said first and second signals for deriving a warning signal that is indicative of the proximity of said source and for determining the ratio of said second signal to said first signal, said ratio being representative of the directional heading of said source with respect to said system;
- and
- means for cancelling the earth's magnetic field in the region of said sensor means, whereby the sensitivity of said sensor means to said alternating magnetic field is enhanced.
Dependencies are inferred from the claim text.