US3696518A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vehicle direction sensing and steering systems using magnetic flux responsive means
Assignee: Allard Way Holdings Ltd
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Filing: 1970-06-15
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Granted: 1972-10-10
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Expires: 1990-06-15
Abstract
Abstract A fluxgate magnetometer circuit is described using a null method of indicating the magnitude and phase of a predetermined component of magnetic field lying along its axis. A correction circuit corrects the output of the fluxgate magnetometer circuit for (i) errors resulting from extraneous magnetic fields which detract from or augment a component of magnetic flux being measured, and (ii) errors due to distortion of the predetermined component of flux by the proximity of magnetizable materials.
Inventors
- 👤 Andrew Francis Vincent Leat
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 06:51
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/02; G01R33/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
538 words
A system responsive to the electrical outputs of at least a first and a second flux measuring apparatus, said first apparatus producing an output representative of the magnetic field strength in a first direction and said second apparatus producing an output representative of the magnetic field strength in a second direction, said system comprising first signal generating means providing an output representing the modifying effect on said first apparatus output of those components of stray magnetic fields lying along said first direction, second signal generating means providing an output representing the modifying effect on said second apparatus output of those components of stray magnetic fields lying along said second direction, first subtracting means, first means feeding the output of said first apparatus and the output of said first signal generating means to said first subtracting means to produce an output from said first subtracting means representative of the difference between the outputs of said first apparatus and said first signal generating means, second subtracting means, second means feeding the output of said second apparatus and the output of said second signal generating means to said second subtracting means to produce an output from said second subtracting means representative of the difference between the outputs of said second apparatus and said second signal generating means, first multiplying means having a first multiplying factor third means feeding the output of said first subtracting means to said first multiplying means, to produce an output from said first multiplying means representative of the product of said first multiplying factor and the output of said first subtracting means,, second multiplying means having a second multiplying factor, fourth means feeding the output of said second subtracting means to said second multiplying means to produce an output from said second multiplying means representative of the product of said second multiplying factor and the output of said second subtraction means, third multiplying means having a third multiplying factor, fifth means feeding the output of the first subtracting means to the third multiplying means to produce an output from the third multiplying means representative of the product of the third multiplying factor and the output of the first subtracting means fourth multiplying means having a fourth multiplying factor, sixth means feeding the output of the second subtracting means to the fourth multiplying means to produce an output from the fourth multiplying means representative of the product of the fourth multiplying factor and the output of the second subtracting means first and second summing means, seventh means feeding the outputs of said first and fourth multiplying means to said first summing means, the first and fourth multiplying factors being a function of a known distortion of the magnetic field in which the system lies such that the output from the first summing means is representative of the output from one said apparatus corrected for the magnetic modifying and distorting effects, and eighth means feeding the outputs of the second and third multiplying meaNs to the second summing means, the second and third multiplying factors being a function of the said known distortion such that the output of the second summing means is representative of the output from the other said apparatus corrected for the modifying and distorting effects.
Claim 2
Independent Claim
538 words
A system responsive to the electrical outputs of at least a first and a second flux measuring apparatus, said first apparatus producing an output representative of the magnetic field strength in a first direction and said second apparatus producing an output representative of the magnetic field strength in a second direction, said system comprising first signal generating means providing an output representing the modifying effect on said first apparatus output of those components of stray magnetic fields lying along said first direction, second signal generating means providing an output representing the modifying effect on said second apparatus output of those components of stray magnetic fields lying along said second direction, first subtracting means, first means feeding the output of said first apparatus and the output of said first signal generating means to said first subtracting means to produce an output from said first subtracting means representative of the difference between the outputs of said first apparatus and said first signal generating means, second subtracting means, second means feeding the output of said second apparatus and the output of said second signal generating means to said second subtracting means to produce an output from said second subtracting means representative of the difference between the outputs of said second apparatus and said second signal generating means, first multiplying means having a first multiplying factor third means feeding the output of said first subtracting means to said first multiplying means, to produce an output from said first multiplying means representative of the product of said first multiplying factor and the output of said first subtracting means,, second multiplying means having a second multiplying factor, fourth means feeding the output of said second subtracting means to said second multiplying means to produce an output from said second multiplying means representative of the product of said second multiplying factor and the output of said second subtraction means, third multiplying means having a third multiplying factor, fifth means feeding the output of the first subtracting means to the third multiplying means to produce an output from the third multiplying means representative of the product of the third multiplying factor and the output of the first subtracting means fourth multiplying means having a fourth multiplying factor, sixth means feeding the output of the second subtracting means to the fourth multiplying means to produce an output from the fourth multiplying means representative of the product of the fourth multiplying factor and the output of the second subtracting means first and second summing means, seventh means feeding the outputs of said first and fourth multiplying means to said first summing means, the first and fourth multiplying factors being a function of a known distortion of the magnetic field in which the system lies such that the output from the first summing means is representative of the output from one said apparatus corrected for the magnetic modifying and distorting effects, and eighth means feeding the outputs of the second and third multiplying meaNs to the second summing means, the second and third multiplying factors being a function of the said known distortion such that the output of the second summing means is representative of the output from the other said apparatus corrected for the modifying and distorting effects.
Claim 3
Dependent Claim
115 words
A system according to claim 1 wherein each said flux measuring apparatus comprises, magnetic flux converting means producing an alternating magnetic field in dependence on the said magnetic field strength in the corresponding said direction a coil, means mounting said coil in said alternating magnetic field, means responsive to the output of said coil to produce a corresponding current varying in dependence on the output of the coil, means for feeding saiD current to said coil to tend to produce a magnetic field therein equal and opposite to said predetermined component, and means responsive to said corresponding current to produce an electrical output dependent on the said magnetic field strength in the said corresponding direction.
Claim 4
Dependent Claim
145 words
A system according to claim 2 wherein said flux converting means comprises a first magnetically permeable member a first coil mounted on said first magnetically permeable member a second magnetically permeable member a second coil mounted on said second magnetically permeable member, means mounting said first coil and first magnetically permeable member at right angles with respect to said second coil and second magnetically permeable member for equal mutual magnetic coupling along a direction parallel to a said corresponding direction, an alternating current source, and means connecting said first and second coils to be supplied respectively in anti-phase by said source, whereby said first and second coils produce zero resultant field when the said magnetic field strength in the corresponding direction is zero, and said alternating current source co-operating to cause periodic of each said magnetic member in turn to produce said alternating magnetic field.
Claim 5
Dependent Claim
71 words
A system according to claim 1, including sensing means responsive to the electrical input applied to electrical equipment producing variations of said stray magnetic fields, to produce a control signal, and means connecting the first and second multiplying means to the sensing means to receive the control signal, and in which, the first and second multiplying means respectively include means responsive to the control signal to set their respective multiplying factors.
Claim 6
Dependent Claim
367 words
A system according to claim 1, additionally responsive to the electrical output of a third flux measuring apparatus, said third flux measuring apparatus producing an output representative of the magnetic field strength in a third direction, said first, second and third directions being mutually perpendicular, said system including third signal generating means providing an output representing the modifying effect on said third apparatus output of those stray magnetic field components lying along said third direction, third subtracting means, eighth means feeding the output of said third apparatus and the output of said third signal generating means to said third subtracting means to produce an output from said third subtracting means representative of the difference between the outputs of said third apparatus and said third signal generating means, fifth and sixth multiplying means respectively having fifth and sixth multiplying factors ninth means for feeding the output of the first and second subtracting means respectively to the fifth and sixth multiplying means to produce outputs from the fifth and sixth multiplying means respectively representative of the product of the output of the first subtracting means and the fifth multiplying factor and of the product of the output of the second subtracting means and the sixth multiplying factor and for feeding the outputs of the fifth and sixth multiplying means to be additionally summed respectively in the first and second summing means, seventh, eighth and ninth multiplying means respectively having seventh, eighth and ninth multiplying factors tenth means for feeding the outputs of the first, second and third subtractions means respectively to the seventh eighth and ninth multiplying means to produce outputs respectively representative of the product of the output of the first subtracting means and the seventh multiplying factor the product of the output of the second subtracting means and the eighth multiplying factor, and the product of the output of the third subtracting means and the ninth multiplying factor, third summing means, and eleventh means feeding the outputs of the seventh, eighth and ninth multiplying meAns to the third summing means to produce an output from the third summing means representative of the output of the third flux measuring apparatus connected for the magnetic modifying and distorting effects.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-10 | 1976-04-10 | 1976-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-10 | 1980-04-10 | 1980-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-10 | 1984-04-10 | 1984-10-10 | $7700.00 | Window Closed / Lapsed |