Adaptive adjustment method for output stage bandwidth of fiber-optic gyroscope

Abstract

The invention relates to a fiber-optic gyroscope output stage bandwidth self-adaptive adjustment method, belongs to the technical field of fiber-optic gyroscope signal processing, and can analyze acceleration and speed data output by a system in real time, judge the bandwidth range of an input signal and dynamically adjust the bandwidth of the system in combination with task requirements. Therefore, adaptive balance between the dynamic response capability and the detection precision is realized, and the real-time performance and the applicability of the system are improved. The adjusting method comprises the following steps: obtaining an angular acceleration based on the angular velocity of the fiber-optic gyroscope closed-loop detection system of a carrier input signal; based on the angular velocity and the angular acceleration, adjusting the response frequency band of the fiber-optic gyroscope closed-loop detection system to adapt to the bandwidth range of the carrier angular velocity; obtaining a bandwidth reference index based on the power spectrum of the angular velocity; according to the angular velocity bandwidth range and the actual task demand, dynamically adjusting the bandwidth adjustment model in combination with the bandwidth reference index to obtain a final bandwidth adjustment model; and adaptively adjusting the bandwidth of an output signal channel by using the final bandwidth adjustment model.

Description

Technical Field

[0001] This invention relates to the field of fiber optic gyroscope signal processing technology, and specifically to a method for adaptive adjustment of the output stage bandwidth of a fiber optic gyroscope. Background Technology

[0002] Fiber optic gyroscopes, as high-precision angular velocity sensors, are widely used in aerospace, shipbuilding, and other fields for inertial navigation and attitude control. However, traditional fiber optic gyroscope closed-loop detection systems typically employ a fixed bandwidth design, which has significant limitations in practical applications. In dynamic measurement scenarios, the bandwidth of the input signal is uncertain, potentially including both low-frequency steady changes and high-frequency rapid changes. Fixed-bandwidth systems struggle to adapt to this characteristic, primarily manifesting as a conflict between dynamic response and accuracy, and a mismatch between bandwidth and task requirements.

[0003] Specifically, while excessively wide bandwidth can capture high-frequency input signals, it introduces more high-frequency noise, leading to a decrease in measurement accuracy. Conversely, while excessively narrow bandwidth can suppress noise and improve the accuracy of low-frequency signals, the system's response capability to fast dynamic signals is insufficient, failing to accurately reflect transient characteristics. Because the bandwidth and accuracy requirements vary across different application scenarios, a fixed bandwidth design is difficult to adjust according to actual task requirements, resulting in the system failing to achieve an optimal balance between response speed and detection accuracy.

[0004] Meanwhile, most existing bandwidth adjustment methods rely on manual setting or fixed filter design, lacking an adaptive adjustment mechanism and making it difficult to optimize in real time based on input signal characteristics during operation. Therefore, this paper proposes an adaptive bandwidth adjustment method for fiber optic gyroscopes to meet the measurement requirements of fiber optic gyroscopes under different bandwidths in multi-task scenarios. Summary of the Invention

[0005] In view of this, the present invention provides a method for adaptive adjustment of the output bandwidth of a fiber optic gyroscope, which can analyze the acceleration and velocity data output by the system in real time, determine the bandwidth range of the input signal, and dynamically adjust the system bandwidth according to the task requirements, thereby achieving an adaptive balance between dynamic response capability and detection accuracy, and improving the real-time performance and applicability of the system.

[0006] This invention provides a method for adaptive bandwidth adjustment of the output stage of a fiber optic gyroscope, the specific steps of which are as follows:

[0007] S1. Obtain the angular velocity of the fiber optic gyroscope closed-loop detection system for the carrier input signal; perform differential processing on the angular velocity Ω(t) to obtain the angular acceleration;

[0008] S2. Based on angular velocity and angular acceleration, adjust the response frequency band of the fiber optic gyroscope closed-loop detection system to adapt to the bandwidth range of the carrier's angular velocity; obtain the bandwidth reference index based on the power spectrum of the input signal;

[0009] S3. Based on the input signal bandwidth range and actual task requirements, and combined with the bandwidth reference index extracted in step S2, dynamically adjust the parameters of the output filter of the bandwidth adjustment model to obtain the final bandwidth adjustment model.

[0010] S4. Adaptively adjust the bandwidth of the output signal channel using the final bandwidth adjustment model.

[0011] Optionally, the bandwidth reference metrics include quantified evaluation response band shift direction metrics and angular velocity equivalent bandwidth.

[0012] Optionally, based on angular velocity and angular acceleration, a quantified evaluation index for the direction of frequency band shift, F(t), is obtained, expressed as:

[0013]

[0014] in, and These represent the average angular velocity and average angular acceleration of the data within the sampling time t, respectively; α and β represent variable coefficients, and preferably, the ranges of α and β should be determined according to the characteristics of the gyroscope.

[0015] Optionally, the specific steps for obtaining the equivalent bandwidth of angular velocity are as follows: obtain the power spectrum of the input angular velocity signal; obtain the cumulative energy distribution of angular velocity based on the power spectrum; obtain the total energy of angular velocity; obtain the peak frequency of the peak point in the power spectrum; seek the optimal bandwidth range at the peak frequency; and obtain the equivalent bandwidth of angular velocity based on the optimal bandwidth range.

[0016] Optionally, the specific steps for the dynamic adjustment of the final bandwidth adjustment model are as follows:

[0017] The cutoff frequency and order of the initial filter are set based on the quantitative evaluation of the response bandwidth shift direction index F(t) and the angular velocity equivalent bandwidth BW:

[0018]

[0019] Among them, f c (0) N represents the initial cutoff frequency; (0) The initial order is represented by η; η is a scaling factor used to control the range of filter order variation; f high and f low These represent the highest and lowest frequencies within the optimal bandwidth range, respectively.

[0020] The cutoff frequency and filter order are dynamically adjusted, expressed as follows:

[0021]

[0022] in, and N (j+1) This represents the filter cutoff frequency and order after the j-th adjustment; and N (j) The filter cutoff frequency and order are represented by μ1 and μ2; μ1 and μ2 are the adjustment step sizes; sgn(·) is the sign function indicating the adjustment direction.

[0023] The adjustment is terminated when the cutoff frequency adjustment tends to converge, or when the filter adjustment order exceeds the maximum limit.

[0024] Optionally, the power spectrum of the input angular velocity signal is expressed as:

[0025]

[0026] Where P[k] is the angular velocity Ω(t) at the k-th frequency f k The power value at the point; Ω[k] represents the discrete Fourier transform of the angular velocity Ω(t) at the k-th frequency; N represents the number of sampling points; k is the frequency index.

[0027] Optionally, the cumulative energy distribution of angular velocity is expressed as:

[0028]

[0029] Where E[m] represents the frequency from the initial frequency f0 to the m-th frequency f m The cumulative energy of the input signal, where m is the index of the maximum frequency point covered by the cumulative energy; N represents the number of sampling points; P[k] is the angular velocity Ω(t) at the k-th frequency f. k The power value at that location.

[0030] Optionally, the peak frequency of the peak point in the power spectrum is expressed as:

[0031]

[0032] Where, k p This is the index for the peak power.

[0033] Optionally, the angular velocity equivalent bandwidth BW is expressed as:

[0034] BW = f high -f low

[0035] Among them, f high and f low These represent the highest and lowest frequencies within the optimal bandwidth range, respectively.

[0036] Compared with the prior art, the present invention has at least the following beneficial effects: it has dynamic bandwidth adaptive capability, and by analyzing the amplitude and changing trend of angular velocity Ω(t) and angular acceleration a(t) in real time, combined with the power spectrum energy accumulation criterion, it dynamically adjusts the cutoff frequency of the output stage filter to achieve bandwidth adaptive optimization, and meets the compatibility of multiple scenarios and the adaptability of task requirements. Attached Figure Description

[0037] Figure 1 The flowchart of the fiber optic gyroscope output stage bandwidth adaptive adjustment method of the present invention is as follows. Figure 1 ;

[0038] Figure 2 The flowchart of the adaptive bandwidth adjustment model algorithm for the output stage of the fiber optic gyroscope in this invention is as follows. Figure 2 . Detailed Implementation

[0039] To better understand the above-described objectives, features, and advantages of the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other. Furthermore, the present invention can be implemented in other ways different from those described herein; therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0040] A specific embodiment of the present invention, such as Figure 1 A method for adaptively adjusting the output bandwidth of a fiber optic gyroscope is disclosed, and the specific steps are as follows:

[0041] S1. Obtain the angular velocity of the fiber optic gyroscope closed-loop detection system for the carrier input signal; perform differential processing on the angular velocity Ω(t) to obtain the angular acceleration, expressed as:

[0042]

[0043] Where a(t) n ) represents t n Angular acceleration at time t; Δt is the sampling time interval; Ω(t) n ) and Ω(t n-1 ) are respectively t n and t n-1 The angular velocity value at time t.

[0044] Furthermore, the angular acceleration at each moment is stored in chronological order to obtain an angular acceleration information set a(t) that represents the dynamic change of the sampling time t of the fiber optic gyroscope closed-loop detection system.

[0045] S2. Based on angular velocity and angular acceleration, adjust the response frequency band of the fiber optic gyroscope closed-loop detection system to adapt to the bandwidth range of the carrier's angular velocity; obtain the bandwidth reference index based on the power spectrum of the input signal;

[0046] Among them, the bandwidth reference indicators include the quantitative evaluation response frequency band shift direction indicator F(t) and the angular velocity equivalent bandwidth BW.

[0047] The specific steps are as follows:

[0048] S21. Based on angular velocity and angular acceleration, obtain the quantified evaluation index F(t) for the frequency band shift direction, expressed as:

[0049]

[0050] in, and These represent the average angular velocity and average angular acceleration of the data within the sampling time t, respectively; α and β represent variable coefficients, and preferably, the ranges of α and β should be determined according to the characteristics of the gyroscope.

[0051] Understandably, when the angular velocity |Ω(t)| and angular acceleration |a(t)| are large, it indicates that the fiber optic gyroscope closed-loop detection system is undergoing strong high-frequency dynamic changes. The frequency range of the angular velocity signal is wide, containing more high-frequency components. Therefore, the bandwidth of the fiber optic gyroscope closed-loop detection system should be increased to capture these input signals, causing the response frequency band of the fiber optic gyroscope closed-loop detection system to shift towards higher frequencies. When the angular velocity |Ω(t)| and angular acceleration |a(t)| are small, it indicates that the changes in the fiber optic gyroscope closed-loop detection system are relatively stable. Therefore, the bandwidth should be reduced, and the system's response frequency band should shift towards lower frequencies to improve the system's measurement accuracy and suppress noise.

[0052] S22. Obtain the power spectrum of the input angular velocity signal, expressed as:

[0053]

[0054] Where P[k] is the angular velocity Ω(t) at the k-th frequency f k The power value at the point; Ω[k] represents the discrete Fourier transform of the angular velocity Ω(t) at the k-th frequency; N represents the number of sampling points (i.e., signal length); k is the frequency index.

[0055] Further, Frequency range is f s This indicates the sampling frequency (i.e., the update rate of angular velocity).

[0056] S23. Obtain the cumulative energy distribution of angular velocity based on the power spectrum. The expression is:

[0057]

[0058] Where E[m] represents the frequency from the initial frequency f0 = 0 to the m-th frequency. The cumulative energy of the input signal, where m is the index of the maximum frequency point covered by the cumulative energy.

[0059] S24, Take At that time, the total energy E that gains angular velocity total The expression is:

[0060]

[0061] S25. Obtain the peak frequency of the peak point in the power spectrum, expressed as:

[0062]

[0063] Where, k p This is the index for the peak power.

[0064] Furthermore, the expression for the peak point in the power spectrum is: max(P[k p ]).

[0065] S26, at peak frequency f p Seeking the optimal bandwidth range [f] low ,f high This allows the energy within this bandwidth to account for 95% of the entire signal frequency band, as expressed in the following expression:

[0066]

[0067] Where, k h and k l These represent the peak frequency f. p The highest frequency f within the optimal bandwidth range high and lowest frequency f low The index.

[0068] Furthermore, in order to allow the signal bandwidth to adaptively shift according to real-time conditions, the highest frequency f is adjusted. high and lowest frequency f low Make the following adjustments to adjust the highest frequency f. high For example, compare F1·E[k] respectively. h ] and E[k h+1 ], F2·E[k h ] and E[k h-1 The size of ], that is and and The size, if the comparison result is:

[0069]

[0070] Then f high Shift the boundary to the right, i.e., index k h+1 The corresponding f high+1 As the new f high Boundary; otherwise, f high Left shift of the boundary, i.e., index k h-1 The corresponding f high-1 As the new f high Boundary. Among them, α t β1, α2, and β2 represent variable coefficients, and preferably, their ranges should be determined according to the characteristics of the gyroscope; k h+1 Indicates k h Shift right by one index value; k h-1 Indicates k h Shift left by one index value; f high+1 Indicates k h+1 The frequency corresponding to the index value; f high-1 Indicates k h-1 The frequency corresponding to the index value.

[0071] Move until the adjusted bandwidth range [f] low ,f high The energy reaches 95% of the entire signal frequency band within the range.

[0072] S27. Obtain the equivalent bandwidth BW of the angular velocity, the expression is:

[0073] BW = f high -f low .

[0074] S3. Based on the input signal bandwidth range and actual task requirements, and combined with the bandwidth reference index extracted in step S2, dynamically adjust the parameters of the output filter of the bandwidth adjustment model to obtain the final bandwidth adjustment model.

[0075] Specifically, the cutoff frequency f of the optimal output filter is obtained by using the quantized evaluation response frequency band shift direction index F(t) and the angular velocity equivalent bandwidth BW. c The expression is:

[0076] f c =g(F(t),BW)

[0077] When the quantitative evaluation of the response frequency band shift direction F(t) indicates that the system has a need for higher frequencies, the cutoff frequency is dynamically adjusted in conjunction with the value of the angular velocity equivalent bandwidth BW, so that the filter can respond to the frequency characteristics of the signal.

[0078] Furthermore, for scenarios where the frequency distribution of angular velocity in a fiber optic gyroscope closed-loop detection system changes rapidly, this invention increases the filter order to obtain a steeper frequency response, thereby more accurately separating signal and noise. The filter order M is dynamically adjusted using the real-time estimated signal bandwidth change ΔBW, expressed as:

[0079]

[0080] Where η is a scaling factor used to control the range of filter order variation; Indicates rounding up;

[0081] |ΔBW| represents the absolute value of the bandwidth difference between the current time t and the previous time t-1.

[0082] Furthermore, the specific steps for the dynamic adjustment of the final bandwidth adjustment model are described as follows:

[0083] (1) Set the cutoff frequency and order of the initial filter based on the quantitative evaluation response frequency band shift direction index F(t) and the angular velocity equivalent bandwidth BW:

[0084]

[0085] Among them, f c (0) N represents the initial cutoff frequency; (0) Indicates the initial order.

[0086] When the initial quantized evaluation response frequency band shift direction index F(t) indicates a signal trend that is biased towards higher frequencies, the cutoff frequency shifts towards f. high Closer, or conversely towards f low near.

[0087] (2) Dynamically adjust the cutoff frequency and filter order, as expressed by:

[0088]

[0089] in, and N (j+1) This represents the filter cutoff frequency and order after the j-th adjustment; and N (j) The filter cutoff frequency and order are represented by μ1 and μ2; μ1 and μ2 are the adjustment step sizes; sgn(·) is the sign function indicating the adjustment direction.

[0090] This invention adjusts the cutoff frequency in real time based on changes in F(t) and BW, bringing it as close as possible to the center of the signal's main frequency band. When ΔBW is large, the filter order N... (j) Increase the filter order N to obtain a steeper frequency response for separating signal and noise; when ΔBW is small, the filter order N...(j) Reduce computational complexity and signal delay.

[0091] (3) The adjustment is terminated when the cutoff frequency adjustment tends to converge, or when the filter adjustment order exceeds the maximum limit. The expression is:

[0092]

[0093] Where, ε f To adjust the threshold for the cutoff frequency, N max To adjust the maximum value limit of the order.

[0094] The output filter designed using parameters obtained from the model in this invention can dynamically adjust the bandwidth range of the output signal.

[0095] S4. Adaptively adjust the bandwidth of the output signal channel using the final bandwidth adjustment model.

[0096] The method of the present invention can dynamically optimize bandwidth according to the characteristics of real-time input signals and task requirements. This method can realize the measurement requirements of fiber optic gyroscopes in multiple scenarios with different bandwidths, especially in low bandwidth and small dynamic scenarios.

[0097] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for adaptive bandwidth adjustment of the output stage of a fiber optic gyroscope, characterized in that, The specific steps are as follows: S1. Obtain the angular velocity of the fiber optic gyroscope closed-loop detection system for the carrier input signal; perform differential processing on the angular velocity Ω(t) to obtain the angular acceleration; S2. Based on angular velocity and angular acceleration, adjust the response frequency band of the fiber optic gyroscope closed-loop detection system to adapt to the bandwidth range of the carrier's angular velocity; obtain the bandwidth reference index based on the power spectrum of the input signal; S3. Based on the input signal bandwidth range and actual task requirements, and combined with the bandwidth reference index extracted in step S2, dynamically adjust the parameters of the output filter of the bandwidth adjustment model to obtain the final bandwidth adjustment model. S4. Adaptively adjust the bandwidth of the output signal channel using the final bandwidth adjustment model.

2. The method for adaptive bandwidth adjustment of the output stage of a fiber optic gyroscope according to claim 1, characterized in that, Bandwidth reference metrics include quantitative evaluation of response frequency band shift direction metrics and angular velocity equivalent bandwidth.

3. The method for adaptive bandwidth adjustment of the output stage of a fiber optic gyroscope according to claim 2, characterized in that, Based on angular velocity and angular acceleration, the quantitative evaluation index F(t) for the frequency band shift direction is obtained, and its expression is: in, and These represent the average angular velocity and average angular acceleration of the data within the sampling time t, respectively; α and β represent variable coefficients, and preferably, the ranges of α and β should be determined according to the characteristics of the gyroscope.

4. The fiber optic gyroscope output stage bandwidth adaptive adjustment method according to claim 2, characterized in that, The specific steps to obtain the equivalent bandwidth of angular velocity are as follows: obtain the power spectrum of the input angular velocity signal; obtain the cumulative energy distribution of angular velocity based on the power spectrum; obtain the total energy of angular velocity; obtain the peak frequency of the peak point in the power spectrum; seek the optimal bandwidth range at the peak frequency; obtain the equivalent bandwidth of angular velocity based on the optimal bandwidth range.

5. The method for adaptive bandwidth adjustment of the output stage of a fiber optic gyroscope according to claim 1, characterized in that, The specific steps for the dynamic adjustment of the final bandwidth adjustment model are as follows: The cutoff frequency and order of the initial filter are set based on the quantitative evaluation of the response bandwidth shift direction index F(t) and the angular velocity equivalent bandwidth BW: Among them, f c (0) N represents the initial cutoff frequency; (0) The initial order is represented by η; η is a scaling factor used to control the range of filter order variation; f high and f low These represent the highest and lowest frequencies within the optimal bandwidth range, respectively. The cutoff frequency and filter order are dynamically adjusted, expressed as follows: Among them, f c (j+1) and N (j+1) f represents the filter cutoff frequency and order after the j-th adjustment; c (j) and N (j) The filter cutoff frequency and order are represented by μ1 and μ2; μ1 and μ2 are the adjustment step sizes; sgn(·) is the sign function indicating the adjustment direction. The adjustment is terminated when the cutoff frequency adjustment tends to converge, or when the filter adjustment order exceeds the maximum limit.

6. The fiber optic gyroscope output stage bandwidth adaptive adjustment method according to claim 4, characterized in that, The power spectrum of the input angular velocity signal is expressed as: Where P[k] is the angular velocity Ω(t) at the k-th frequency f k The power value at the point; Ω[k] represents the discrete Fourier transform of the angular velocity Ω(t) at the k-th frequency; N represents the number of sampling points; k is the frequency index.

7. The fiber optic gyroscope output stage bandwidth adaptive adjustment method according to claim 4, characterized in that, The cumulative energy distribution of angular velocity is expressed as: Where E[m] represents the frequency from the initial frequency f0 to the m-th frequency f m The cumulative energy of the input signal, where m is the index of the maximum frequency point covered by the cumulative energy; N represents the number of sampling points; P[k] is the angular velocity Ω(t) at the k-th frequency f. k The power value at that location.

8. The method for adaptive bandwidth adjustment of the output stage of a fiber optic gyroscope according to claim 4, characterized in that, The peak frequency of the peak point in the power spectrum is expressed as: Where, k p This is the index for the peak power.

9. The fiber optic gyroscope output stage bandwidth adaptive adjustment method according to claim 4, characterized in that, The equivalent bandwidth of angular velocity, BW, is expressed as: BW=f high -f low Among them, f high and f low These represent the highest and lowest frequencies within the optimal bandwidth range, respectively.

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