Pumping-detection non-orthogonal angle calibration method for atomic spin inertial measurement

Abstract

A pumping-detection non-orthogonal angle calibration method for atomic spin inertia measurement is used for accurately evaluating a pumping-detection laser non-orthogonal angle, and is characterized by comprising the following steps: step 1, placing an atomic spin inertia measurement device in a working state, adjusting a z-axis magnetic field bias to a compensation point, and setting a Z-axis magnetic field bias to a compensation point; 2, a magnetic field By with the size of 0.075 nT is applied to the y-axis direction, and a longitudinal electron spin polarization initial value # imgabs0 # at the moment is recorded; step 3, changing pumping laser power, and recording a pumping laser power value Iin each time, a corresponding inertial output signal steady-state value Sx and a longitudinal electron spin polarization value # imgabs 1 #; step 4, fitting parameters in the step 3 by adopting a particle swarm algorithm to obtain a value of a pumping-detection laser non-orthogonal angle alpha.

Description

Technical Field

[0001] The present invention relates to a pump-detection non-orthogonal angle calibration method for atomic spin inertia measurement, which aims to accurately calibrate the pump-detection laser non-orthogonal angle of an atomic spin inertia measurement device online, and is applicable to the technical field of high-precision active compensation of residual magnetic field of atomic inertia measurement devices. Background Art

[0002] In recent years, atomic spin inertial measurement devices have attracted widespread attention due to their important role in high-precision sensing and navigation systems. Their high sensitivity and excellent stability in rotational motion detection have been widely recognized and widely used in aerospace, deep-sea exploration and other fields.

[0003] The non-orthogonal angle of the pump-detection laser is limited by the assembly accuracy of the prototype and is difficult to be adjusted to 0. The influence of longitudinal polarization on the inertial measurement signal always exists. Therefore, the non-orthogonal angle of the pump-detection laser can be regarded as an inherent property of the atomic spin inertial measurement system, and software compensation can be used to reduce the influence. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a pump-detection non-orthogonal angle calibration method for atomic spin inertial measurement to accurately evaluate the pump-detection laser non-orthogonal angle.

[0005] The technical solution of the present invention is as follows:

[0006] A pump-detection non-orthogonal angle calibration method for atomic spin inertial measurement, characterized by comprising the following steps:

[0007] Step 1: put the atomic spin inertial measurement device into working state, adjust the z-axis magnetic field bias to the compensation point, and record the initial value of the longitudinal electron spin polarization at this time.

[0008] Step 2: Apply a magnetic field B of 0.075nT in the y-axis direction. y ;

[0009] Step 3: Change the pumping laser power and record the pumping laser power value I each time. in , the corresponding inertial output signal steady-state value S x and the longitudinal electron spin polarization

[0010] Step 4, using a particle swarm algorithm to fit the parameters in step 3 to obtain the value of the pump-detection laser non-orthogonal angle α.

[0011] The step 1 includes: placing the atomic gas chamber in a high temperature state by means of a non-magnetic heating device, polarizing the atoms in the alkali metal gas chamber by means of pumping light to reach a working state, and compensating the residual magnetic field inside the device to a value close to zero by means of a magnetic field coil, so that the residual magnetism in the barrel has no effect on subsequent measurements.

[0012] The step 2 includes: using a signal generator to apply a constant current to the y-axis magnetic field coil, thereby generating a constant magnetic field of 0.075 nT.

[0013] The step 3 includes: adjusting the pump laser controller to change the current size, thereby changing the pump laser power, and obtaining I in , obtain S through the host computer software x as well as

[0014] The step 4 includes the following expression:

[0015]

[0016] Among them, k and b are parameters to be fitted. is the intermediate quantity, is the transverse electron spin polarization value, γ e is a known constant, B z is the z-axis magnetic field, B e ,B n are all parameters to be fitted, B y =0.075, is the total electron relaxation rate, and a is the parameter to be fitted.

[0017] The advantages of the present invention compared with the prior art are:

[0018] (1) The present invention proposes a method for calibrating the pump-detection non-orthogonal angle for atomic spin inertial measurement, which can measure and calibrate the non-orthogonal angle of the pump-detection laser online, greatly improving the convenience and efficiency of system operation.

[0019] (2) The present invention adopts an intelligent optimization algorithm for fitting calculation, which improves the accuracy and reliability of non-orthogonal angle calibration and overcomes the errors caused by signal noise or instability in traditional methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of parameter coordinates involved in a pumping-detection non-orthogonal angle calibration method for atomic spin inertia measurement of the present invention. Figure 1 1 represents the pump laser, 2 represents the non-orthogonal angle of the pump-detection laser to be calibrated, and 3 represents the longitudinal electron spin polarization value. 4 is the transverse electron spin polarization value

[0021] Figure 2 The present invention is a schematic flow chart of a pump-detection non-orthogonal angle calibration method for atomic spin inertia measurement. Figure 2 The method includes step 1, polarizing atoms and compensating residual magnetic field, and recording the initial value of longitudinal electron spin polarization; step 2, applying a constant magnetic field on the Y axis; step 3, changing the pumping light power, and recording the longitudinal electron spin polarization value and the output signal; and step 4, particle swarm algorithm fitting. DETAILED DESCRIPTION

[0022] Below is the attached figure ( Figure 1-Figure 2 ) and Examples illustrate the present invention.

[0023] Figure 1 It is a schematic diagram of parameter coordinates involved in a pumping-detection non-orthogonal angle calibration method for atomic spin inertia measurement of the present invention. Figure 2 The figure is a flow chart of a method for pumping-detecting non-orthogonal angle calibration for atomic spin inertial measurement according to the present invention. Figure 1 to Figure 2 As shown, a pump-detection non-orthogonal angle calibration method for atomic spin inertial measurement includes the following steps: Step 1, placing the atomic spin inertial measurement device in a working state, adjusting the z-axis magnetic field bias to the compensation point, and recording the initial value of the longitudinal electron spin polarization at this time Step 2: Apply a magnetic field B of 0.075nT in the y-axis direction. y ; Step 3, change the pump laser power (see pump laser Figure 1 Mark 1), record the pump laser power value I each time in , the corresponding inertial output signal steady-state value S x and the longitudinal electron spin polarization (See Figure 1 Step 4, using a particle swarm algorithm to fit the parameters in step 3, obtain the value of the pump-detection laser non-orthogonal angle α (see Figure 1 Mark 2).

[0024] The step 1 includes: using a non-magnetic heating device to keep the atomic gas chamber in a high temperature state, and using pumping light to polarize the atoms in the alkali metal gas chamber to reach a working state, and using a magnetic field coil to compensate the residual magnetic field inside the device to a value close to zero, so that the residual magnetism in the barrel has no effect on subsequent measurements. The step 2 includes: using a signal generator to apply a constant current to the y-axis magnetic field coil, thereby generating a constant magnetic field of 0.075nT. The step 3 includes: adjusting the pumping laser controller to change the current size, thereby changing the pumping laser power, and obtaining I through an optical power detector. in , obtain S through the host computer software x as well as

[0025] The step 4 includes the following expression:

[0026]

[0027]

[0028]

[0029]

[0030] Among them, k and b are parameters to be fitted. is the intermediate quantity, is the transverse electron spin polarization value (see Figure 1 Mark 4), γ e is a known constant, B z is the z-axis magnetic field, B e ,B n are all parameters to be fitted, B y =0.075, is the total electron relaxation rate, and a is the parameter to be fitted.

[0031] The present invention discloses a method for calibrating pump-detection non-orthogonal angles for atomic spin inertial measurement. The method takes the pump-detection laser non-orthogonal angles in the atomic spin inertial measurement system as the research object, and proposes an innovative solution for online measurement of the pump-detection laser non-orthogonal angles. The method obtains different inertial output signals by changing the pump laser power, and calculates the non-orthogonal angles by fitting using an intelligent optimization algorithm. The present invention can achieve the calibration of the pump-detection laser non-orthogonal angles without destroying the atomic spin polarization state.

[0032] like Figure 1 As shown, the angle formed by the pump laser (1) and the z-axis direction is the non-orthogonal angle (2) of the pump-detection laser.

[0033] like Figure 2 As shown, the specific calibration process for calibrating the non-orthogonal angles of the pump-detection laser.

[0034] Specifically include the following:

[0035] A pump-detection non-orthogonal angle calibration method for atomic spin inertial measurement, comprising the following steps:

[0036] Step 1: put the atomic spin inertial measurement device into working state, adjust the z-axis magnetic field bias to the compensation point, and record the initial value of the longitudinal electron spin polarization at this time.

[0037] Step 2: Apply a magnetic field B of 0.075nT in the y-axis direction. y .

[0038] Step 3: Change the pumping laser power and record the pumping laser power value I each time. in , the corresponding inertial output signal steady-state value S x and the longitudinal electron spin polarization

[0039] Step 4, using a particle swarm algorithm to fit the parameters in step 3 to obtain the value of the pump-detection laser non-orthogonal angle.

[0040] The step 1 is to put the atomic spin inertial measurement device into working state, adjust the z-axis magnetic field bias to the compensation point, and record the longitudinal electron spin polarization value at this time. The specific process is to keep the atomic gas chamber in a high-temperature state through a non-magnetic heating device, and use pumping light to polarize the atoms in the alkali metal gas chamber to reach the working state, and use the magnetic field coil to compensate the residual magnetic field inside the device to a value close to zero, so that the residual magnetism in the barrel has no effect on subsequent measurements.

[0041] The step 2 applies a magnetic field of 0.075 nT in the y-axis direction. The specific process is to use a signal generator to apply a constant current to the y-axis magnetic field coil, thereby generating a magnetic field of constant magnitude.

[0042] Step 3 changes the pumping laser power and records the pumping laser power value I each time. in , the corresponding inertial output signal steady-state value S x and the longitudinal electron spin polarization The specific process is to adjust the pump laser controller to change the current size, thereby changing the pump laser power. The pump laser power value I can be obtained through the optical power detector. in , obtain the steady-state value S of the inertial output signal through the host computer software x and the longitudinal electron spin polarization

[0043] The step 4 uses a particle swarm algorithm to fit the parameters in the step 3 to obtain the value of the pump-detection laser non-orthogonal angle. The specific process is to set the initial parameters of the particle swarm algorithm and determine the function to be fitted as follows:

[0044]

[0045] in

[0046]

[0047] where k, b, B e ,B n,a,α are the parameters to be fitted,γ e is a known constant, B y is the magnetic field value of 0.075nT applied in step 2, is the transverse electron spin polarization value, is the longitudinal electron spin polarization value recorded in step 3, is the initial value of the longitudinal electron spin polarization in step 1, I in is the pump laser power value recorded in step 3. Finally, the value of the pump-detection laser non-orthogonal angle α can be obtained.

[0048] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in the field. It is pointed out here that the above description helps those skilled in the art to understand the invention, but does not limit the protection scope of the invention. Any equivalent replacement, modification and / or simplification of the above description without departing from the essence of the invention falls within the protection scope of the invention.

Claims

1. A pump-detection non-orthogonal angle calibration method for atomic spin inertial measurement, characterized in that: The following steps are involved: Step 1: put the atomic spin inertial measurement device into working state, adjust the z-axis magnetic field bias to the compensation point, and record the initial value of the longitudinal electron spin polarization at this time. Step 2: Apply a magnetic field B of 0.075nT in the y-axis direction. y ; Step 3: Change the pumping laser power and record the pumping laser power value I each time. in , the corresponding inertial output signal steady-state value S x and the longitudinal electron spin polarization Step 4, using a particle swarm algorithm to fit the parameters in step 3 to obtain the value of the pump-detection laser non-orthogonal angle α.

2. The pump-detection non-orthogonal angle calibration method for atomic spin inertial measurement according to claim 1, characterized in that: The step 1 includes: placing the atomic gas chamber in a high temperature state by means of a non-magnetic heating device, polarizing the atoms in the alkali metal gas chamber by means of pumping light to reach a working state, and compensating the residual magnetic field inside the device to a value close to zero by means of a magnetic field coil, so that the residual magnetism in the barrel has no effect on subsequent measurements.

3. The pump-detection non-orthogonal angle calibration method for atomic spin inertial measurement according to claim 1, characterized in that: The step 2 includes: using a signal generator to apply a constant current to the y-axis magnetic field coil, thereby generating a constant magnetic field of 0.075 nT.

4. The pump-detection non-orthogonal angle calibration method for atomic spin inertial measurement according to claim 1, characterized in that: The step 3 includes: adjusting the pump laser controller to change the current size, thereby changing the pump laser power, and obtaining I in , obtain S through the host computer software x as well as 5. The pump-detection non-orthogonal angle calibration method for atomic spin inertial measurement according to claim 1, characterized in that: The step 4 includes the following expression: Among them, k and b are parameters to be fitted. is the intermediate quantity, is the transverse electron spin polarization value, γ e is a known constant, B z is the z-axis magnetic field, B e ,B n are all parameters to be fitted, B y =0.075, is the total electron relaxation rate, and a is the parameter to be fitted.

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