Multi-parameter measurement method of SERF gyroscope based on magnetic field phase frequency response

Abstract

The application is based on a SERF gyroscope multi-parameter measurement method of magnetic field phase frequency response, first measuring B y The phase frequency characteristic curve of the alternating magnetic field response is obtained through a lock-in amplifier y The response phase of the SERF atomic spin gyroscope under the alternating magnetic field is zero; different amplitude direct current magnetic fields are applied to the z axis respectively, the above process is repeated, and then B y The linear fitting of the zero-phase frequency value of the alternating magnetic field response can obtain the accurate values of the electronic magnetic field and the slowing-down factor. The method can realize the accurate measurement of the electronic magnetic field, the nuclear spin magnetic field, the slowing-down factor and the alkali metal atom density of the SERF atomic spin gyroscope in a very short time without causing the relaxation of the SERF atomic spin gyroscope.

Claims

1. A multi-parameter measurement method for SERF gyroscopes based on magnetic field phase frequency response, characterized in that, Includes the following steps: Step 1, apply to the SERF gyroscope , It is an alternating magnetic field in the y-direction. ,get The phase-frequency response curve; Step 2: Obtain the phase frequency response curve. The response zero-phase frequency ω value; Step 3: After applying a DC magnetic field Bz of different amplitudes in the z-direction, return to step 1 until the preset number of returns is reached; Step 4, for different amplitudes of Bz A linear fit is performed on the response zero-phase frequency ω, and the horizontal axis is... , The deviation of Bz from the magnetic field value of Bc is given by the vertical axis ω, which yields the electron magnetic field Be and the slowing factor Q. Step 5: Calculate the nuclear spin magnetic field Bn using the "gyroscope compensation point" Bc and the electron magnetic field Be; calculate the electron polarizability Pe using the slowing factor Q; and calculate the alkali metal atomic density using the formula for the equivalent magnetic field of alkali metal electron spin. ; Step 1 includes: heating the alkali metal gas cell in the SERF gyroscope to the required operating temperature, turning on the pump laser, and using the pump laser to polarize the alkali metal atoms. The alkali metal atoms polarize the inert gas nuclei's spins through spin exchange collisions. Once the system reaches a steady state, magnetic field cross-modulation compensation technology is used to compensate the magnetic field. At this point, the gyroscope operates at the "gyroscope compensation point" Bc. satisfy The x-axis magnetic field Bx satisfies The y-axis magnetic field By satisfies With the SERF gyroscope stationary in inertial space, and By representing sinusoidal waves of different frequencies with amplitudes of 0.3 nT and frequencies ω ranging from 10 Hz to 400 Hz, the phase values ​​of the magnetic field response at different frequencies ω are obtained. Plot the frequency ω-phase value The curve is obtained by fitting it with the magnetic field transfer function. Phase frequency response curve of alternating magnetic field response.

2. The SERF gyroscope multi-parameter measurement method based on magnetic field phase frequency response according to claim 1, characterized in that, Step 2 includes: obtaining through a lock-in amplifier. Record the frequency value of the point where the phase value is zero in the phase frequency response curve. , This is the first frequency value.

3. The SERF gyroscope multi-parameter measurement method based on magnetic field phase frequency response according to claim 2, characterized in that, Step 3 includes: the preset number of returns is 6 times, and Bz is set based on Bc, with Bz= nT, Bz= nT;Bz= nT;Bz= nT;Bz= nT;Bz= nT, and repeat steps 1 and 2 after each change of the magnetic field, recording the different amplitudes Bz. The frequency value with a phase of zero in the phase frequency response curve , These are the second to seventh frequency values.

4. The SERF gyroscope multi-parameter measurement method based on magnetic field phase frequency response according to claim 3, characterized in that, Step 4 includes ω is the x-coordinate and ω is the y-coordinate. It includes 7 coordinate values, equal to 0 nT, 2nT, 4nT, 6nT, 8nT, 10nT, and 12nT respectively. ω includes 7 coordinate values, respectively. , , , , , ,as well as The fitting yielded The slope of the -ω line is The intercept is .

5. The SERF gyroscope multi-parameter measurement method based on magnetic field phase frequency response according to claim 4, characterized in that, Step 5 includes: ， = ， Q= ， ， ， in The Fermi contact constant is... The permeability of free space, The magnetic moment of an alkali metal atom. It is the electron gyromagnetic ratio.

6. The SERF gyroscope multi-parameter measurement method based on magnetic field phase frequency response according to claim 5, characterized in that, ， ， in, , This is the third zero of the Y-axis magnetic field transfer function. Let be the real part of the second pole of the Y-axis magnetic field transfer function. The transverse relaxation rate of electrons. It is the electron gyromagnetic ratio.

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