Detection method and detector of a disruption, positioning method and system using said method
First Claim
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1. A method for detecting a disturber of an amplitude of a magnetic field amplitude, the disturber being in proximity to a uniaxial magnetic field source, said method comprising:
- emitting several magnetic fields from the uniaxial magnetic field source, said several magnetic fields being emitted at at least three different frequencies, f1, f2, . . . fj, wherein, of said several magnetic fields emitted, two magnetic fields having different unspecified frequencies chosen among said at least three different frequencies f1, f2, . . . fj, have amplitudes when emitted being related to each other by a predetermined ratio, which ratio is constant and equal to one,using a sensor spaced from said uniaxial magnetic field source, measuring amplitudes of said two magnetic fields emitted at said different unspecified frequencies, and reporting an amplitude disturber when a ratio between the measured amplitudes of said two magnetic fields emitted diverges from one by a predetermined threshold.
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Abstract
This method for detecting a disturber of magnetic field amplitude comprises:
- the emitting (62) of several magnetic fields of different frequencies from a same uniaxial magnetic field source, the amplitudes of the magnetic field emitted at two different unspecified frequencies being related to each other by a predetermined ratio,
- the measurement (64) of the amplitude of these magnetic fields at different frequencies by means of a same sensor, and
- the reporting (70) of an amplitude disturber if a ratio between two of said measured amplitudes diverges from a predetermined threshold of the predetermined ratio which relates the amplitudes of the magnetic fields emitted at the same frequencies and, if not, the absence of any reporting.
12 Citations
10 Claims
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1. A method for detecting a disturber of an amplitude of a magnetic field amplitude, the disturber being in proximity to a uniaxial magnetic field source, said method comprising:
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emitting several magnetic fields from the uniaxial magnetic field source, said several magnetic fields being emitted at at least three different frequencies, f1, f2, . . . fj, wherein, of said several magnetic fields emitted, two magnetic fields having different unspecified frequencies chosen among said at least three different frequencies f1, f2, . . . fj, have amplitudes when emitted being related to each other by a predetermined ratio, which ratio is constant and equal to one, using a sensor spaced from said uniaxial magnetic field source, measuring amplitudes of said two magnetic fields emitted at said different unspecified frequencies, and reporting an amplitude disturber when a ratio between the measured amplitudes of said two magnetic fields emitted diverges from one by a predetermined threshold. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A manufacture comprising a tangible and non-transitory computer-readable medium having encoded thereon software for detecting a disturber of an amplitude of a magnetic field amplitude in proximity to a uniaxial magnetic field source, said software including instructions that, when executed by a computer, cause:
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emitting of several magnetic fields from the uniaxial magnetic field source, said several magnetic fields being emitted at at least three different frequencies, f1, f2, . . . fj, wherein, of said the several magnetic fields emitted, two magnetic fields having different unspecified frequencies chosen among said at least three different frequencies f1, f2, . . . fj, have amplitudes when emitted being related to each other by a predetermined ratio, which ratio is constant and equal to one, using a sensor, spaced from said uniaxial magnetic field source, measuring amplitudes of said two magnetic fields emitted at said different unspecified frequencies, and reporting of an amplitude disturber when a ratio between said two measured amplitudes diverges from one by a predetermined threshold.
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8. An apparatus
for detecting a disturber of magnetic field amplitude, comprising: -
a uniaxial magnetic field source configured to emit several magnetic fields at at least three different frequencies, f1, f2, fj, wherein, of said several magnetic fields emitted, two magnetic fields having different unspecified frequencies chosen among said at least three different frequencies, f1, f2, fj, have amplitudes when emitted being related to one another by a predetermined ratio, which ratio is constant and equal to one, a sensor, spaced from said uniaxial magnetic field source, to measure amplitudes of said two magnetic fields emitted at said different unspecified frequencies, and an indicator configured to report presence of a disturber of amplitude of the magnetic field only if a ratio between the measured amplitudes of said two magnetic fields emitted diverges from one by a predetermined threshold. - View Dependent Claims (9, 10)
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Specification