A method and system for improving the accuracy of laser inertial navigation system vibration based on filter compensation

Abstract

This invention relates to the field of inertial navigation and discloses a laser inertial navigation vibration method and system based on filter compensation. The method improves the navigation accuracy of the laser inertial navigation system under vibration conditions by using a low-order FIR low-pass filter for filtering and then compensating for the low-order filtering accuracy by using the difference between the high-order filtering result and the low-order filtering result.

Description

Technical Field

[0001] This invention relates to the field of inertial navigation, and in particular to a method and system for improving the accuracy of laser inertial navigation based on filter compensation. Background Technology

[0002] Inertial navigation is currently the only navigation method that simultaneously possesses full autonomy, high stealth, and strong anti-jamming capabilities, and is widely used in launch vehicles and guided weapons. Laser inertial navigation systems (SIRS), as high-precision inertial measurement devices, are subject to random vibrations or shocks during launch or flight. As a critical measurement and guidance device for the launch vehicle, the dynamic characteristics of the SIRS under vibration conditions, especially its navigation accuracy, directly affect the success or failure of the mission.

[0003] Under vibration conditions, laser inertial navigation systems (INS) become sensitive to high-frequency interference from the carrier. To extract effective motion information from the INS's output signal, a low-pass filter needs to be designed to remove this high-frequency interference. Finite impulse response (FIR) filters offer high stability and reliability, avoiding stability issues and nonlinear distortion. They provide precise filtering characteristics and flexible filter design, and exhibit good linear phase characteristics.

[0004] The dynamic characteristics of laser inertial navigation systems (INS) impose requirements on navigation accuracy under vibration conditions. Under the same frequency requirements, low-order filters have less attenuation of high-frequency interference and lower navigation accuracy. High-order filters have better filtering characteristics in the frequency domain and can more accurately filter out high-frequency interference information, thus improving navigation accuracy. However, high-order filters also introduce greater phase delay, affecting the real-time performance of navigation results. Summary of the Invention

[0005] This invention provides a method and system for improving the vibration navigation accuracy of laser inertial navigation systems based on filter compensation, in order to solve the problem of low navigation accuracy of laser inertial navigation systems under vibration conditions in the prior art.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

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

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

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

[0010] S3: Determine the accuracy difference between the filter outputs of the low-order FIR low-pass filter and the high-order FIR low-pass filter, perform spectral analysis on the accuracy difference, and perform filter compensation on the filter output of the low-order FIR low-pass filter to obtain the compensated filter data.

[0011] S4: Based on the compensated filtered data, perform inertial navigation calculation under vibration conditions to obtain navigation results.

[0012] Optionally, S1 includes:

[0013] S11: Receive the first input information from the user, and in response to the first input information, enter the filter design interface;

[0014] S12: In the filter design interface, the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the low-order FIR low-pass filter are received from the user, and a low-order FIR low-pass filter is generated 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 the parameters of the low-order FIR low-pass filter.

[0016] Optionally, S2 includes:

[0017] S21: Receive the second input information from the user, and in response to the second input information, enter the filter design interface;

[0018] S22: In the filter design interface, the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the high-order FIR low-pass filter are received from the user, and a high-order FIR low-pass filter is generated 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 the parameters of the low-order FIR low-pass filter.

[0020] Optionally, S3 includes:

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

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

[0023] S33: The accuracy difference Δ(k-τ) between the filter output y2(k) of the high-order FIR low-pass filter and the filter output y1(k-τ) of the low-order FIR low-pass filter at synchronous filter output satisfies the following relationship:

[0024] Δ(k-τ)=y2(k)-y1(k-τ);

[0025] S34: Perform spectral 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 precision difference Δ(k-τ) is shifted to the right by T-τ sampling periods to obtain Δ(kT), and Δ(kT) is used to compensate the filter output y1(k) of the low-order FIR low-pass filter to obtain the compensated filter output y(k).

[0026] Where T is the low-frequency oscillation period T Δ The value of n must be an integer multiple of τ; n = 1, 2, 3, ..., and the value of n must satisfy T ≥ τ; the 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 for signals of different frequencies, satisfying the following relationship:

[0028]

[0029] Where τ(ω) is the group delay; d is the differential; φ(ω) is the phase response; and ω is the frequency.

[0030] Secondly, this application provides a laser inertial navigation vibration accuracy improvement system based on filter compensation, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the method described in the first aspect above.

[0031] Beneficial effects:

[0032] This application provides a method for improving the vibration navigation accuracy of laser inertial navigation systems based on filter compensation. By using a low-order FIR low-pass filter for filtering, and then using the difference between the high-order filtering result and the low-order filtering result to compensate for the accuracy of the low-order filtering, the navigation accuracy of the laser inertial navigation system under vibration conditions is improved while ensuring the real-time performance of the filtering output. Attached Figure Description

[0033] Figure 1 Algorithm flow of a laser inertial navigation method based on filter compensation according to a preferred embodiment of the present invention Figure 1 ;

[0034] Figure 2 Algorithm flow of a laser inertial navigation method based on filter compensation according to a preferred embodiment of the present invention Figure 2 ;

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

[0036] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "connected" or "linked" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up," "down," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0038] Please see Figure 1-Figure 2 This application provides a laser inertial navigation vibration method based on filter compensation, comprising:

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

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

[0041] S3: Determine the accuracy difference between the filter outputs of the low-order FIR low-pass filter and the high-order FIR low-pass filter, perform spectral analysis on the accuracy difference, and perform filter compensation on the filter output of the low-order FIR low-pass filter to obtain the compensated filter data.

[0042] S4: Based on the compensated filtered data, perform inertial navigation calculation under vibration conditions to obtain navigation results.

[0043] The aforementioned laser inertial navigation method based on filter compensation addresses the problem of low navigation accuracy under vibration conditions in existing laser inertial navigation systems. This method improves navigation accuracy under vibration conditions by using a low-order FIR low-pass filter and then compensating for the low-order filtering accuracy using the difference between the high-order and low-order filtering results.

[0044] Optionally, S1 includes:

[0045] S11: Receive the first input information from the user, and in response to the first input information, enter the filter design interface;

[0046] S12: In the filter design interface, the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the low-order FIR low-pass filter are received from the user, and a low-order FIR low-pass filter is generated 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 the 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 using MATLAB. Enter "fdatool + Enter" in the MATLAB command line window to access 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; enter the order of the designed low-order FIR low-pass filter in the input box; enter the units of the laser inertial navigation system's sampling frequency in Units; enter the sampling frequency in Fs; determine the passband cutoff frequency Fpass and stopband cutoff frequency Fstop of the filter based on the vibration conditions of the laser inertial navigation system 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 can be 8th or 16th order.

[0050] Optionally, S2 includes:

[0051] S21: Receive the second input information from the user, and in response to the second input information, enter the filter design interface;

[0052] S22: In the filter design interface, the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the high-order FIR low-pass filter are received from the user, and a high-order FIR low-pass filter is generated 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 the 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 using MATLAB. Enter "fdatool + Enter" in the MATLAB command line window to access 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; enter the order of the designed high-order FIR low-pass filter in the input box; enter the units of the laser inertial navigation system's sampling frequency in Units; enter the sampling frequency in Fs; determine the passband cutoff frequency Fpass and stopband cutoff frequency Fstop of the filter based on the vibration conditions of the laser inertial navigation system 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 alternative implementation, the order of the high-order FIR low-pass filter can be 128.

[0056] Optionally, S3 includes:

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

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

[0059] S33: The accuracy difference Δ(k-τ) between the filter output y2(k) of the high-order FIR low-pass filter and the filter output y1(k-τ) of the low-order FIR low-pass filter at synchronous filter output satisfies the following relationship:

[0060] Δ(k-τ)=y2(k)-y1(k-τ);

[0061] S34: Perform spectral 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 precision difference Δ(k-τ) is shifted to the right by T-τ sampling periods to obtain Δ(kT), and Δ(kT) is used to compensate the filter output y1(k) of the low-order FIR low-pass filter to obtain the compensated filter output y(k).

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

[0063] 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 for signals of different frequencies, satisfying the following relationship:

[0064]

[0065] Where τ(ω) is the group delay; d is the differential; φ(ω) is the phase response; and ω is the frequency.

[0066] In one example, Figure 3 In the software system interface diagram, input the parameters of the low-order FIR low-pass filter and the high-order FIR low-pass filter respectively. Click "Import Vibration Data" to read the acceleration pulse data and gyroscope pulse data that need to be calculated for vibration navigation. The data format requires that it be saved as pure numeric text in a 6-column format. The first to third columns are the acceleration pulse data of the XYZ axes, and the fourth to sixth columns are the gyroscope pulse data of the XYZ axes. Click "Import Calibration Parameters" to import the most recent calibration results of the inertial navigation system.

[0067] Click "Calculation Results" and wait for the "Calculation Complete" 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 eastward velocity error, northward velocity error and azimuth velocity error, respectively; the seventh to ninth columns are the navigation solution eastward displacement error, northward displacement error and azimuth displacement error, respectively.

[0068] This 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. When the processor executes the computer program, it implements the steps of the above-described method. This laser inertial navigation system based on filter compensation can implement various embodiments of the above-described method and achieve the same beneficial effects; further details are omitted here.

[0069] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A laser inertial navigation vibration method based on filter compensation, characterized in that, include: S1: Design an FIR digital filter based on the first preset rule to obtain a low-order FIR low-pass filter; S2: Design an FIR digital filter based on the second preset rule to obtain a high-order FIR low-pass filter; S3: Determine the accuracy difference between the filter outputs of the low-order FIR low-pass filter and the high-order FIR low-pass filter, perform spectral analysis on the accuracy difference, and perform filter compensation on the filter output of the low-order FIR low-pass filter to obtain the compensated filter data. S4: Based on the compensated filtered data, perform inertial navigation calculation under vibration conditions to obtain navigation results; S3 includes: S31: Calculate the group delay of the high-order FIR low-pass filter. and the group delay of the low-order FIR low-pass filter ; S32: The filtered output of the low-order FIR low-pass filter Move right The filtered output is obtained from each sampling period. The filtered output and the filtered output of the higher-order FIR low-pass filter Synchronization, among which, ; S33: The output of the high-order FIR low-pass filter during synchronous filtering. and the filtered output of the low-order FIR low-pass filter Poor accuracy It satisfies the following relationship: ； S34: Regarding the aforementioned accuracy difference Spectral analysis was performed to obtain the accuracy difference. low-frequency oscillation period ,make The accuracy difference Move right Each sampling period yields ,Will Compensation to the filter output of the low-order FIR low-pass filter The compensated filtered output is obtained. ; in, Low-frequency oscillation period Integer multiples of; , The value of must satisfy Low-frequency oscillation period The unit is s.

2. The laser inertial navigation method based on filter compensation according to claim 1, characterized in that, S1 includes: S11: Receive the first input information from the user, and in response to the first input information, enter the filter design interface; S12: In the filter design interface, the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the low-order FIR low-pass filter are received from the user, and a low-order FIR low-pass filter is generated 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 the parameters of the low-order FIR low-pass filter.

3. The laser inertial navigation method based on filter compensation according to claim 1, characterized in that, S2 includes: S21: Receive the second input information from the user, and in response to the second input information, enter the filter design interface; S22: In the filter design interface, the order, sampling frequency, unit of sampling frequency, passband cutoff frequency and stopband cutoff frequency of the high-order FIR low-pass filter are received from the user, and a high-order FIR low-pass filter is generated 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 the parameters of the low-order FIR low-pass filter.

4. The laser inertial navigation method based on filter compensation according to claim 1, 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 for signals of different frequencies, satisfying the following relationship: ； in, Group delay; It is a differential; For phase frequency response; For frequency.

5. 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, it implements the steps of the method described in any one of claims 1 to 4.

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