Laser inertial measurement unit vibration navigation precision improving method and system based on filtering compensation

Abstract

The invention relates to the field of inertial measurement unit navigation, and discloses a laser inertial measurement unit vibration navigation method and system based on filtering compensation, and the method comprises the following steps: filtering by using a low-order FIR low-pass filter, and compensating the low-order filtering precision by using a difference value between a high-order filtering result and a low-order filtering result. Therefore, the navigation precision of the laser inertial measurement unit under the vibration condition is improved.

Description

Technical Field

[0001] The present invention relates to the field of inertial navigation system, and in particular to a method and system for improving the accuracy of laser inertial navigation system vibration based on filtering compensation. Background Art

[0002] Inertial navigation is currently the only navigation method that is fully autonomous, highly concealed, and highly resistant to interference. It is widely used in launch vehicles and guided weapons. As a high-precision inertial measurement device, the laser inertial group will be affected by random vibration or impact during the launch or flight of the carrier. As a key measurement and guidance device for the carrier, the dynamic characteristics of the laser inertial group under vibration conditions, especially the navigation accuracy, are directly related to the success or failure of the carrier's mission.

[0003] Under vibration conditions, the laser inertial group will be sensitive to the high-frequency interference information of the carrier. In order to extract effective motion information from the output signal of the laser inertial group, a low-pass filter needs to be designed to filter out the high-frequency interference information. The finite impulse response (FIR) filter has high stability and reliability, will not have stability problems and nonlinear distortion, can achieve accurate filtering characteristics and flexible filter design, and has good linear phase characteristics.

[0004] The dynamic characteristics of the laser inertial group have requirements for navigation accuracy under vibration conditions. Under the same frequency requirements, low-order filters have little attenuation on high-frequency interference and low navigation accuracy. High-order filters have better filtering characteristics in the frequency domain and can more accurately filter out high-frequency interference information, thereby improving navigation accuracy. However, high-order filters will also introduce greater phase delays, affecting the real-time nature of navigation results. Summary of the invention

[0005] The present invention provides a method and system for improving the vibration navigation accuracy of a laser inertial group based on filtering compensation, so as to solve the problem of low navigation accuracy of the laser inertial group under vibration conditions in the prior art.

[0006] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0007] In a first aspect, the present invention provides a method for improving the accuracy of laser inertial navigation system vibration based on filtering compensation, comprising:

[0008] S1: Designing an FIR digital filter based on a first preset rule to obtain a low-order FIR low-pass filter;

[0009] S2: Designing an FIR digital filter based on a second preset rule to obtain a high-order FIR low-pass filter;

[0010] S3: determining the precision difference between the filtering outputs of the low-order FIR low-pass filter and the high-order FIR low-pass filter, performing filter compensation on the filtering output of the low-order FIR low-pass filter by performing spectrum analysis on the precision difference, and obtaining compensated filtering data;

[0011] S4: Perform inertial navigation settlement under vibration conditions based on the compensated filtered data to obtain a navigation result.

[0012] Optionally, the S1 includes:

[0013] S11: receiving first input information input by a user, and entering a filter design interface in response to the first input information;

[0014] S12: In the filter design interface, receiving the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the low-order FIR low-pass filter input by the user, and generating a low-order FIR low-pass filter based on the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the low-order FIR low-pass filter;

[0015] S13: Obtain parameters of the low-order FIR low-pass filter.

[0016] Optionally, the S2 includes:

[0017] S21: receiving second input information input by a user, and entering a filter design interface in response to the second input information;

[0018] S22: In the filter design interface, receiving the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the high-order FIR low-pass filter input by the user, and generating a high-order FIR low-pass filter based on the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the high-order FIR low-pass filter;

[0019] S23: Obtain parameters of the low-order FIR low-pass filter.

[0020] Optionally, the S3 includes:

[0021] S31: Calculate the group delay τ2 of the high-order FIR low-pass filter and the group delay τ1 of the low-order FIR low-pass filter;

[0022] S32: The filter output y1(k) of the low-order FIR low-pass filter is right-shifted by τ sampling periods to obtain a filter output y1(k-τ), and the filter output y1(k-τ) is synchronized with the filter output y2(k) of the high-order FIR low-pass filter, wherein τ=τ2-τ1;

[0023] S33: When the filtering output is synchronized, the precision difference Δ(k-τ) between the filtering output y2(k) of the high-order FIR low-pass filter and the filtering output y1(k-τ) of the low-order FIR low-pass filter satisfies the following relationship:

[0024] Δ(k-τ)=y2(k)-y1(k-τ);

[0025] S34: Perform spectrum analysis on the precision difference Δ(k-τ) to obtain the low-frequency oscillation period T of the precision difference Δ(k-τ) Δ , let T = nT Δ , the accuracy difference Δ(k-τ) is right-shifted by T-τ sampling periods to obtain Δ(kT), and Δ(kT) is compensated to the filtering output y1(k) of the low-order FIR low-pass filter to obtain the compensated filtering output y(k);

[0026] Where T is the low frequency oscillation period T Δ integer multiples; n=1,2,3,…, the value of n must satisfy T≥τ; low-frequency oscillation period T Δ The unit is s.

[0027] Optionally, the group delay is the relative delay introduced by the low-order FIR low-pass filter and the high-order FIR low-pass filter to signals of different frequencies, satisfying the following relationship:

[0028]

[0029] Among them, τ(ω) is the group delay; d is the differential; φ(ω) is the phase-frequency response; ω is the frequency;

[0030] In a second aspect, the present application provides a laser inertial group vibration navigation accuracy improvement system based on filtering compensation, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described in the first aspect when executing the computer program.

[0031] Beneficial effects:

[0032] The present application provides a method for improving the vibration navigation accuracy of a laser inertial group based on filtering compensation. The method uses a low-order FIR low-pass filter for filtering, and then compensates for the low-order filtering accuracy by using the difference between the high-order filtering result and the low-order filtering result, thereby improving the navigation accuracy of the laser inertial group under vibration conditions while ensuring the real-time performance of the filtering output. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The algorithm flow of a laser inertial group vibration navigation method based on filter compensation in the preferred embodiment of the present invention is as follows Figure 1 ;

[0034] Figure 2 The algorithm flow of a laser inertial group vibration navigation method based on filter compensation in the preferred embodiment of the present invention is as follows Figure 2 ;

[0035] Figure 3 This is a software system interface diagram of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate quantity restrictions, but indicate the existence of at least one. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship also changes accordingly.

[0038] See also Figure 1-Figure 2 The present application provides a laser inertial group vibration navigation method based on filter compensation, comprising:

[0039] S1: Designing an FIR digital filter based on a first preset rule to obtain a low-order FIR low-pass filter;

[0040] S2: Designing an FIR digital filter based on a second preset rule to obtain a high-order FIR low-pass filter;

[0041] S3: determining the precision difference between the filtering outputs of the low-order FIR low-pass filter and the high-order FIR low-pass filter, performing filter compensation on the filtering output of the low-order FIR low-pass filter by performing spectrum analysis on the precision difference, and obtaining compensated filtering data;

[0042] S4: Perform inertial navigation settlement under vibration conditions based on the compensated filtered data to obtain a navigation result.

[0043] The above-mentioned laser inertial group vibration navigation method based on filter compensation is aimed at the problem of low navigation accuracy under laser inertial group vibration conditions in the prior art, and a laser inertial group vibration navigation method based on filter compensation is proposed. This method uses a low-order FIR low-pass filter for filtering, and then uses the difference between the high-order filtering result and the low-order filtering result to compensate for the low-order filtering accuracy, thereby improving the navigation accuracy under laser inertial group vibration conditions.

[0044] Optionally, the S1 includes:

[0045] S11: receiving first input information input by a user, and entering a filter design interface in response to the first input information;

[0046] S12: In the filter design interface, receiving the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the low-order FIR low-pass filter input by the user, and generating a low-order FIR low-pass filter based on the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the low-order FIR low-pass filter;

[0047] S13: Obtain parameters of the low-order FIR low-pass filter.

[0048] In this optional implementation, the first input information can be "fdatool+Enter". In one example, the FIR digital filter can be designed through MATLAB. Enter fdatool+Enter in the MATLAB command line window to enter the "Filter Design&Analysis Tool" interface. In the filter design interface, select Lowpass for Response; select FIR Equiripple for Design Method; select Spicify order for Filter order, and fill in the order of the designed low-order FIR low-pass filter in the input box; fill in the unit of the laser inertial group sampling frequency in Units, and fill in the sampling frequency in Fs; determine the passband cutoff frequency Fpass and stopband cutoff frequency Fstop of the filter according to the vibration conditions of the laser inertial group and the actual application environment, click Design Filter to generate the filter, and then click File→Export to export the designed filter parameters;

[0049] In this optional implementation, the order of the low-order FIR low-pass filter may be 8th order or 16th order.

[0050] Optionally, the S2 includes:

[0051] S21: receiving second input information input by a user, and entering a filter design interface in response to the second input information;

[0052] S22: In the filter design interface, receiving the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the high-order FIR low-pass filter input by the user, and generating a high-order FIR low-pass filter based on the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the high-order FIR low-pass filter;

[0053] S23: Obtain parameters of the low-order FIR low-pass filter.

[0054] In this optional implementation, the second input information can be "fdatool+Enter". In one example, the FIR digital filter can be designed through MATLAB. Enter fdatool+Enter in the MATLAB command line window to enter the "Filter Design&Analysis Tool" interface. In the filter design interface, select Lowpass for Response; select FIR Equiripple for Design Method; select Spicify order for Filter order, and fill in the order of the designed high-order FIR low-pass filter in the input box; fill in the unit of the laser inertial group sampling frequency in Units, and fill in the sampling frequency in Fs; determine the passband cutoff frequency Fpass and stopband cutoff frequency Fstop of the filter according to the vibration conditions of the laser inertial group and the actual application environment, click Design Filter to generate the filter, and then click File→Export to export the designed filter parameters;

[0055] In this optional implementation, the order of the high-order FIR low-pass filter may be 128th order.

[0056] Optionally, the S3 includes:

[0057] S31: Calculate the group delay τ2 of the high-order FIR low-pass filter and the group delay τ1 of the low-order FIR low-pass filter;

[0058] S32: The filter output y1(k) of the low-order FIR low-pass filter is right-shifted by τ sampling periods to obtain a filter output y1(k-τ), and the filter output y1(k-τ) is synchronized with the filter output y2(k) of the high-order FIR low-pass filter, wherein τ=τ2-τ1;

[0059] S33: When the filtering output is synchronized, the precision difference Δ(k-τ) between the filtering output y2(k) of the high-order FIR low-pass filter and the filtering output y1(k-τ) of the low-order FIR low-pass filter satisfies the following relationship:

[0060] Δ(k-τ)=y2(k)-y1(k-τ);

[0061] S34: Perform spectrum analysis on the precision difference Δ(k-τ) to obtain the low-frequency oscillation period T of the precision difference Δ(k-τ) Δ , let T = nT Δ , the accuracy difference Δ(k-τ) is right-shifted by T-τ sampling periods to obtain Δ(kT), and Δ(kT) is compensated to the filtering output y1(k) of the low-order FIR low-pass filter to obtain the compensated filtering output y(k);

[0062] Where T is the low frequency oscillation period T Δ integer multiples; n=1,2,3,…, the value of n must satisfy T≥τ; low-frequency oscillation period T Δ The unit is s.

[0063] Optionally, the group delay is a relative delay introduced by the low-order FIR low-pass filter and the high-order FIR low-pass filter to signals of different frequencies, satisfying the following relationship:

[0064]

[0065] Among them, τ(ω) is the group delay; d is the differential; φ(ω) is the phase-frequency response; ω is the frequency.

[0066] In one example, Figure 3 In the software system interface, input the low-order FIR low-pass filter parameters and the high-order FIR low-pass filter parameters respectively. Click "Import Vibration Data" to read the acceleration pulse data and gyro pulse data required to calculate vibration navigation. The data format requires pure digital text saved in 6 columns. The first to third columns are the acceleration pulse data of the XYZ axis, and the fourth to sixth columns are the gyro pulse data of the XYZ axis. Click "Import Calibration Parameters" to import the most recent calibration result of the inertial group.

[0067] Click "Calculate Results" and wait for the "Calculation Completed" window to pop up. You can find a file named result.txt in the vibration data folder, which is the navigation result. The navigation result file consists of nine columns of data. The first to third columns are the navigation solution pitch angle, roll angle and azimuth angle respectively; the fourth to sixth columns are the navigation solution east velocity error, north velocity error and celestial velocity error respectively; the seventh to ninth columns are the navigation solution east displacement error, north displacement error and celestial displacement error respectively.

[0068] The embodiment of the present application also provides a laser inertial navigation system based on filter compensation, including a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements the steps of the above method when executing the computer program. The laser inertial navigation system based on filter compensation can implement various embodiments of the above method and achieve the same beneficial effects, which will not be described in detail here.

[0069] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A laser inertial navigation system vibration navigation method based on filter compensation, characterized in that: include: S1: Designing an FIR digital filter based on a first preset rule to obtain a low-order FIR low-pass filter; S2: Designing an FIR digital filter based on a second preset rule to obtain a high-order FIR low-pass filter; S3: determining the precision difference between the filtering outputs of the low-order FIR low-pass filter and the high-order FIR low-pass filter, performing filter compensation on the filtering output of the low-order FIR low-pass filter by performing spectrum analysis on the precision difference, and obtaining compensated filtering data; S4: Perform inertial navigation settlement under vibration conditions based on the compensated filtered data to obtain a navigation result.

2. The laser inertial navigation system vibration navigation method based on filter compensation according to claim 1 is characterized in that: The S1 includes: S11: receiving first input information input by a user, and entering a filter design interface in response to the first input information; S12: In the filter design interface, receiving the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the low-order FIR low-pass filter input by the user, and generating a low-order FIR low-pass filter based on the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the low-order FIR low-pass filter; S13: Obtain parameters of the low-order FIR low-pass filter.

3. The laser inertial navigation system vibration navigation method based on filter compensation according to claim 1 is characterized in that: The S2 includes: S21: receiving second input information input by a user, and entering a filter design interface in response to the second input information; S22: In the filter design interface, receiving the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the high-order FIR low-pass filter input by the user, and generating a high-order FIR low-pass filter based on the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the high-order FIR low-pass filter; S23: Obtain parameters of the low-order FIR low-pass filter.

4. The laser inertial navigation system vibration navigation method based on filter compensation according to claim 1, characterized in that: The S3 includes: S31: Calculate the group delay τ2 of the high-order FIR low-pass filter and the group delay τ1 of the low-order FIR low-pass filter; S32: The filter output y1(k) of the low-order FIR low-pass filter is right-shifted by τ sampling periods to obtain a filter output y1(k-τ), and the filter output y1(k-τ) is synchronized with the filter output y2(k) of the high-order FIR low-pass filter, wherein τ=τ2-τ1; S33: When the filtering output is synchronized, the precision difference Δ(k-τ) between the filtering output y2(k) of the high-order FIR low-pass filter and the filtering output y1(k-τ) of the low-order FIR low-pass filter satisfies the following relationship: Δ(k-τ)=y2(k)-y1(k-τ); S34: Perform spectrum analysis on the precision difference Δ(k-τ) to obtain the low-frequency oscillation period T of the precision difference Δ(k-τ) Δ , let T = nT Δ , the accuracy difference Δ(k-τ) is right-shifted by T-τ sampling periods to obtain Δ(kT), and Δ(kT) is compensated to the filtering output y1(k) of the low-order FIR low-pass filter to obtain the compensated filtering output y(k); Where T is the low frequency oscillation period T Δ integer multiples; n=1,2,3,…, the value of n must satisfy T≥τ; low frequency oscillation period T Δ The unit is s.

5. The laser inertial navigation system vibration navigation method based on filter compensation according to claim 4 is characterized in that: The group delay is the relative delay introduced by the low-order FIR low-pass filter and the high-order FIR low-pass filter to signals of different frequencies, and satisfies the following relationship: Among them, τ(ω) is the group delay; d is the differential; φ(ω) is the phase-frequency response; ω is the frequency.

6. A laser inertial navigation system based on filter compensation, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method described in any one of claims 1 to 5 are implemented.

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