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US 2008/0290867 A1Published application
Altered sweep bell-bloom magnetometer
AssigneeGeometrics, Inc.
InventorKenneth R. Smith
Life of this patent
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Abstract
A magnetometer is constructed wherein the sweeping is performed at one half the Larmor frequency and has as its center the absorption line. This allows the emitter to tune onto the absorption line twice per cycle as it passes through the line. This causes the increase in absorption as would the normal sweep of a Bell-Bloom magnetometer but avoids the drawbacks, such as drift and heading error.
Claims21
A magnetometer comprising:
- a light emitter;
- an absorption cell containing a material that absorbs light from the light emitter at an increased amount when light from the light emitter has a wavelength equal to a center point of an absorption line;
- and
- wherein the light emitter is configured to vary the wavelength of the light it emits at a frequency equal to one half of a Larmor frequency and vary the wavelength such that a center point of the variation is at the center point of the absorption line.
1 more element
A method for approximation of a function for frequency response correction in a magnetometer, the method comprising:
- measuring a displacement in time of zero crossings of a harmonic frequency, wherein the harmonic frequency comprises a small fundamental frequency developed by modulating a Larmor signal and a larger even harmonic frequency developed by modulating the Larmor signal;
- and
- approximating the amplitudes of the small fundamental frequency and the even harmonic frequency by using the displacement in time of zero crossings as a value for a ratio proportional to a ratio of the amplitudes.
Dependencies are inferred from the claim text.