Patent US4552383A successfully refreshed from Google Patents.
US3568048A
Expired / Lapsed
US
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Three coil system for geophysical prospecting utilizing magnetic time transients
Assignee: SOTELCOM COMMUNICATIONS Inc
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Filing: 1968-12-09
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Granted: 1971-03-02
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Expires: 1988-12-09
Abstract
Abstract A method and apparatus for detecting geophysical anomalies by measuring the naturally occurring audio frequency transient magnetic fields (AFMAG fields) in two planes comprising utilizing three orthogonal coils and processing their output voltages in appropriate proportions to give the effect of an equivalent coil system comprising two pairs of coils with each coil of each pair having its axis inclined at 45* to the horizontal and at 90* to the axis of the other coil of such pair, one pair of such equivalent coils lying in one vertical plane and the other pair of such equivalent coils lying in another vertical plane.
Inventors
- 👤 William A Robinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:37
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/15; G01V3/165
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
154 words
A method of simultaneously measuring any deviations of time transients magnetic fields from the horizontal in two planes comprising orienting three mutually perpendicular coils having predetermined pickup factors in space, whereby voltages are generated therein by the time transient magnetic fields combining the voltage outputs of said coils in a predetermined relationship governed by the actual attitude of said coils in space relative to the horizontal and their pickup factors to produce process voltages corresponding to those obtainable from an equivalent coil system comprising a first pair of coils lying in a first plane having their axes mutually perpendicular and at 45* to the horizon and a second pair of coils lying is a second plane and having their axes mutually perpendicular and at 45* to the horizon, and processing said process voltages to determine any deviation of the transient magnetic fields from the horizontal in either said first plane or said second plane.
Claim 2
Independent Claim
154 words
A method of simultaneously measuring any deviations of time transients magnetic fields from the horizontal in two planes comprising orienting three mutually perpendicular coils having predetermined pickup factors in space, whereby voltages are generated therein by the time transient magnetic fields combining the voltage outputs of said coils in a predetermined relationship governed by the actual attitude of said coils in space relative to the horizontal and their pickup factors to produce process voltages corresponding to those obtainable from an equivalent coil system comprising a first pair of coils lying in a first plane having their axes mutually perpendicular and at 45* to the horizon and a second pair of coils lying is a second plane and having their axes mutually perpendicular and at 45* to the horizon, and processing said process voltages to determine any deviation of the transient magnetic fields from the horizontal in either said first plane or said second plane.
Claim 3
Independent Claim
85 words
A method of simultaneously measuring any deviations of time transient magnetic fields from the horizontal in two planes comprising orienting in space three mutually perpendicular coils having essentially the same pickup factors with one coil essentially vertical and the other two essentially horizontal, adding and subtracting voltages generated by the time transient magnetic fields in said vertical coil and each of said horizontal coils and determining the ratiO of such added and subtracted voltages obtained from said vertical coil and each of said horizontal coils.
Claim 4
Independent Claim
85 words
A method of simultaneously measuring any deviations of time transient magnetic fields from the horizontal in two planes comprising orienting in space three mutually perpendicular coils having essentially the same pickup factors with one coil essentially vertical and the other two essentially horizontal, adding and subtracting voltages generated by the time transient magnetic fields in said vertical coil and each of said horizontal coils and determining the ratiO of such added and subtracted voltages obtained from said vertical coil and each of said horizontal coils.
Claim 5
Dependent Claim
30 words
A method as claimed in claim 2 in which voltages of selected frequencies in substantially the audio range are added and subtracted according to claim 2 and their ratios determined.
Claim 6
Dependent Claim
59 words
A method as claimed in claim 3 in which coils are towed behind an aircraft and the voltages generated in said coils are fed to said aircraft and the sum and difference of the voltages generated in said essentially vertical coil and each of said horizontal coils is measured in said aircraft and their ratios determined in said aircraft.
Claim 7
Dependent Claim
38 words
A method as claimed in claim 4 in which one of said horizontal coils is essentially aligned in the direction of flight and the other of said essentially horizontal coils is essentially perpendicular to the direction of flight.
Claim 8
Dependent Claim
36 words
A method as claimed in claim 2 in which an electromagnetic field of a selected frequency is created at said aircraft and voltages generated in said vertical coil are delivered to and measured in said aircraft.
Claim 9
Dependent Claim
65 words
Means for simultaneously measuring deviations from normal horizontal polarization of naturally occurring magnetic time transients in two planes comprising three mutually perpendicular coils one oriented substantially vertical and the other two substantially horizontal, means for adding and subtracting the voltages generated in said essentially vertical coil and each of said essentially horizontal coils and means for determining the ratios of said added and subtracted voltages.
Claim 10
Dependent Claim
65 words
Means for simultaneously measuring deviations from normal horizontal polarization of naturally occurring magnetic time transients in two planes comprising three mutually perpendicular coils one oriented substantially vertical and the other two substantially horizontal, means for adding and subtracting the voltages generated in said essentially vertical coil and each of said essentially horizontal coils and means for determining the ratios of said added and subtracted voltages.
Claim 11
Independent Claim
148 words
A method of simultaneously measuring any deviations of time transient magnetic fields from the horizontal in two planes comprising orienting in space three mutually perpendicular coils having essentially the same pickup factors with one coil essentially vertical and the other two essentially horizontal, adding and subtracting voltages generated by the time transient magnetic fields in said vertical coil and one of said horizontal coils and determining the ratio of such added and subtracted voltages to indicate any variations of said time transient magnetic fields from the horizontal in a first direction, adding and subtracting voltages generated by the time transient magnetic fields in said vertical coil and the other of said horizontal coils and determining the ratio of such latter added and subtracted voltages to indicate any variations of said time transient magnetic fields from the horizontal in a second direction at right angles to said first direction.
Claim 12
Independent Claim
148 words
A method of simultaneously measuring any deviations of time transient magnetic fields from the horizontal in two planes comprising orienting in space three mutually perpendicular coils having essentially the same pickup factors with one coil essentially vertical and the other two essentially horizontal, adding and subtracting voltages generated by the time transient magnetic fields in said vertical coil and one of said horizontal coils and determining the ratio of such added and subtracted voltages to indicate any variations of said time transient magnetic fields from the horizontal in a first direction, adding and subtracting voltages generated by the time transient magnetic fields in said vertical coil and the other of said horizontal coils and determining the ratio of such latter added and subtracted voltages to indicate any variations of said time transient magnetic fields from the horizontal in a second direction at right angles to said first direction.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |