Frequency modulated continuous wave radar vibration displacement estimation method, system, medium, and device

Abstract

A frequency-modulated continuous wave radar vibration displacement estimation method and system based on dynamic demodulation, medium and equipment, in the method, a fixed frequency-modulated continuous wave radar is used to collect echo signals of a vibrating object surface; the echo signals are amplified, down-converted and low-pass filtered to convert into baseband beat frequency signals, forming a two-dimensional data matrix composed of fast time sampling point number N and slow time sweep frequency number M, zero padding fast Fourier transform is performed on the baseband beat frequency signals of the first sweep cycle, and the phase estimation value of the first sweep cycle is calculated based on the maximum likelihood phase estimator; for the baseband beat frequency signals of the mth sweep cycle, dynamic demodulation is performed and the phase is updated to obtain an updated phase sequence; the updated phase sequence is phase unwrapped; and the phase is converted into a target line-of-sight direction vibration displacement sequence.

Description

Technical Field

[0001] This invention relates to the field of non-contact vibration measurement technology, and in particular to a method, system, medium, and device for estimating vibration displacement using frequency-modulated continuous wave radar based on dynamic demodulation. Background Technology

[0002] In scenarios such as structural health monitoring and rotating machinery condition monitoring, vibration displacement is a crucial physical quantity characterizing the dynamic response of a structure. Frequency-modulated continuous wave radar combines range resolution with phase-sensitive measurement capabilities, enabling subwavelength-level displacement extraction by tracking the phase evolution of continuously swept frequency echoes. However, existing processing procedures typically require first estimating the beat frequency and then demodulating the echoes to extract the phase. If the same fixed beat frequency is used for demodulation across all sweeps, a phase deviation will accumulate linearly over time when the actual beat frequency changes slowly or when there are errors in the beat frequency estimation; this deviation spans across... A phase jump will then occur, significantly distorting the displacement reconstruction results. On the other hand, high-resolution beat frequency estimation methods (such as Chirp-Z transform) are computationally intensive, making them difficult to meet the needs of real-time or large-scale data processing.

[0003] The information disclosed in the background section is only for enhancing the understanding of the background of this invention, and therefore may contain information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method, system, medium, and device for estimating vibration displacement of frequency-modulated continuous wave radar based on dynamic demodulation. It maps the phase difference between adjacent sweep frequencies to a beat frequency correction amount and recursively updates the demodulated beat frequency, making the demodulated beat frequency continuously approach the true beat frequency. This suppresses accumulated phase error and phase jump under conditions of low signal-to-noise ratio or slowly changing beat frequency, while also maintaining low computational complexity, thus achieving high-precision estimation of small vibration displacement.

[0005] A vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation includes:

[0006] Step 1: Use a fixed frequency modulated continuous wave radar to collect echo signals from the surface of the vibrating object;

[0007] Step 2: Amplify, down-convert, and low-pass filter the echo signal to convert it into a baseband beat frequency signal, forming a two-dimensional data matrix consisting of the number of fast-time sampling points N and the number of slow-time sweeps M. , and ;

[0008] Step 3: Apply zero-filling fast Fourier transform to the baseband beat frequency signal of the first sweep cycle, and calculate the phase estimate of the first sweep cycle based on the maximum likelihood phase estimator.

[0009] Step 4: For the first The baseband beat frequency signal of one sweep cycle, Perform dynamic demodulation and update the phase to obtain the updated phase sequence;

[0010] Step 5: Perform phase unrolling on the updated phase sequence;

[0011] Step 6: Convert the phase into a vibration displacement sequence in the target line of sight direction.

[0012] In the aforementioned method for estimating vibration displacement using a frequency-modulated continuous wave radar based on dynamic demodulation, in step 1, the fixed frequency-modulated continuous wave radar adopts a single-transmitter, single-receiver structure, with its installation direction facing the vibrating object. The object vibrates along the radar's line-of-sight. The radar's transmission frequency is set. sampling frequency ,bandwidth Frequency sweep cycle And collect echo signals.

[0013] In the aforementioned method for estimating vibration displacement of frequency-modulated continuous wave radar based on dynamic demodulation, step 3 includes:

[0014] Step 3.1: After performing a zero-filled Fast Fourier Transform on the baseband beat frequency signal of the first sweep cycle, search for spectral peaks near the target range gate to obtain the beat frequency estimate for the first sweep cycle. ;

[0015] Step 3.2: Based on the maximum likelihood phase estimator:

[0016]

[0017] in: For the first Phase estimate for each sweep cycle, This is the baseband beat frequency signal. To increase the number of sampling points in a fast time, For the first Beat frequency estimate for each sweep cycle;

[0018] The calculated phase estimate for the first sweep cycle is... ;

[0019] Step 3.3: Let the updated phase estimate for the first sweep cycle be... .

[0020] In the aforementioned method for estimating vibration displacement of frequency-modulated continuous wave radar based on dynamic demodulation, step 4 includes:

[0021] Step 4.1: For the m-th sweep frequency echo, Repeat steps 4.2 through 4.6;

[0022] Step 4.2: Estimate the initial beat frequency estimate for the m-th sweep cycle. Based on this value, a phase estimate is calculated using the maximum likelihood phase estimator. ;

[0023] Step 4.3: Calculate the phase difference between adjacent sweep cycles:

[0024]

[0025] Step 4.4: Calculate the beat frequency correction:

[0026]

[0027] in: For the sweep bandwidth, The center wavelength, At the speed of light, This is the frequency sweep period;

[0028] Step 4.5: Recursively update the beat frequency estimate used for demodulation:

[0029]

[0030] Step 4.6: Use the updated version The baseband beat frequency signal of the m-th sweep cycle is dynamically demodulated and the phase is recalculated and updated. .

[0031] In the aforementioned method for estimating vibration displacement of frequency-modulated continuous wave radar based on dynamic demodulation, step 5 involves updating the phase... Phase unrolling of the sequence:

[0032]

[0033] in: For phase expansion.

[0034] In the frequency-modulated continuous wave radar vibration displacement estimation method based on dynamic demodulation, in step 6, the phase is converted into a vibration displacement sequence along the target line-of-sight direction.

[0035] The vibration displacement is obtained.

[0036] In the aforementioned method for estimating vibration displacement of frequency-modulated continuous wave radar based on dynamic demodulation, in step 5, the phase unrolling eliminates the discontinuity caused by phase wrapping.

[0037] A system for performing the method includes:

[0038] The acquisition unit uses a fixed-frequency continuous-wave radar to acquire echo signals from the surface of a vibrating object;

[0039] The processing unit amplifies, down-converts, and low-pass filters the echo signal, converting it into a baseband beat frequency signal, forming a two-dimensional data matrix consisting of the number of fast-time sampling points N and the number of slow-time sweeps M. , and ;

[0040] The estimation unit performs zero-fill fast Fourier transform on the baseband beat frequency signal of the first sweep cycle and calculates the phase estimate of the first sweep cycle based on the maximum likelihood phase estimator.

[0041] Update unit, for the first The baseband beat frequency signal of one sweep cycle, Perform dynamic demodulation and update the phase to obtain the updated phase sequence;

[0042] Phase unpacking unit performs phase unpacking on the updated phase sequence;

[0043] The displacement calculation unit converts the phase into a vibration displacement sequence along the target's line of sight.

[0044] A computer storage medium including computer instructions that, when run on a computer, cause the computer to perform the method.

[0045] An electronic device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method when executing the program.

[0046] Compared with the prior art, the present invention has the following advantages: (1) By dynamically updating the demodulation beat frequency by sweeping the frequency, the cumulative phase error and phase jump phenomenon are significantly suppressed; (2) The combination of zero-fill fast Fourier transform and dynamic recursion is adopted to reduce the overall computational complexity while ensuring the beat frequency tracking accuracy; (3) It is suitable for non-contact displacement measurement in complex working conditions such as multi-target vibration, multi-component interference, and low signal-to-noise ratio. Attached Figure Description

[0047] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0048] In the attached diagram:

[0049] Figure 1 This is a flowchart of a high-precision micro-vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation, according to the present invention.

[0050] Figure 2 This is an experimental scenario diagram of a high-precision micro-vibration displacement estimation method based on dynamic demodulation frequency-modulated continuous wave radar provided in an embodiment of the present invention;

[0051] Figure 3 This is a single sinusoidal vibration displacement estimation result diagram of a high-precision micro-vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation provided in an embodiment of the present invention;

[0052] Figure 4 This is a single sinusoidal vibration displacement estimation error diagram of a high-precision micro-vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation provided in an embodiment of the present invention;

[0053] Figure 5 This is a multi-sinusoidal vibration displacement estimation result diagram of a high-precision micro-vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation provided in an embodiment of the present invention;

[0054] Figure 6 This is a multi-sinusoidal vibration displacement estimation error diagram of a high-precision micro-vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation, provided by an embodiment of the present invention. Detailed Implementation

[0055] Specific embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. While specific embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0056] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that different terms may be used to refer to the same component. This specification and claims do not distinguish components based on differences in terminology, but rather on differences in function. The terms "comprising" or "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising but not limited to." The following descriptions are preferred embodiments for carrying out this disclosure; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of this disclosure. The scope of protection of this disclosure is determined by the appended claims.

[0057] To facilitate understanding of the embodiments of this disclosure, further explanations and descriptions will be provided below with reference to the accompanying drawings and specific embodiments. The accompanying drawings do not constitute a limitation on the embodiments of this disclosure.

[0058] like Figures 1 to 6 As shown, this embodiment of the invention provides a method for estimating vibration displacement of frequency-modulated continuous wave radar based on dynamic demodulation, including:

[0059] Step 1: Use a fixed frequency modulated continuous wave radar to collect echo signals from the surface of the vibrating object;

[0060] Step 2: Amplify, down-convert, and low-pass filter the echo signal to convert it into a baseband beat frequency signal, forming a two-dimensional data matrix consisting of the number of fast-time sampling points N and the number of slow-time sweeps M. , and ;

[0061] Step 3: Apply zero-filling fast Fourier transform to the baseband beat frequency signal of the first sweep cycle, and calculate the phase estimate of the first sweep cycle based on the maximum likelihood phase estimator.

[0062] Step 4: For the first The baseband beat frequency signal of one sweep cycle, Perform dynamic demodulation and update the phase to obtain the updated phase sequence;

[0063] Step 5: Perform phase unrolling on the updated phase sequence;

[0064] Step 6: Convert the phase into a vibration displacement sequence in the target line of sight direction.

[0065] In a preferred embodiment of the frequency-modulated continuous wave radar vibration displacement estimation method based on dynamic demodulation, in step 1, the fixed frequency-modulated continuous wave radar adopts a single-transmitter, single-receiver structure, with its installation direction facing the vibrating object. The object vibrates along the radar's line-of-sight direction, and the radar transmission frequency is set. sampling frequency ,bandwidth Frequency sweep cycle And collect echo signals.

[0066] In a preferred embodiment of the frequency-modulated continuous wave radar vibration displacement estimation method based on dynamic demodulation, step 3 includes:

[0067] Step 3.1: After performing a zero-filled Fast Fourier Transform on the baseband beat frequency signal of the first sweep cycle, search for spectral peaks near the target range gate to obtain the beat frequency estimate for the first sweep cycle. ;

[0068] Step 3.2: Based on the maximum likelihood phase estimator:

[0069]

[0070] in: For the first Phase estimate for each sweep cycle, This is the baseband beat frequency signal. To increase the number of sampling points in a fast time, For the first Beat frequency estimate for each sweep cycle;

[0071] The calculated phase estimate for the first sweep cycle is... ;

[0072] Step 3.3: Let the updated phase estimate for the first sweep cycle be... .

[0073] In a preferred embodiment of the frequency-modulated continuous wave radar vibration displacement estimation method based on dynamic demodulation, step 4 includes:

[0074] Step 4.1: For the m-th sweep frequency echo, Repeat steps 4.2 through 4.6;

[0075] Step 4.2: Estimate the initial beat frequency estimate for the m-th sweep cycle. Based on this value, a phase estimate is calculated using the maximum likelihood phase estimator. ;

[0076] Step 4.3: Calculate the phase difference between adjacent sweep cycles:

[0077]

[0078] Step 4.4: Calculate the beat frequency correction:

[0079]

[0080] in: For the sweep bandwidth, The center wavelength, At the speed of light, This is the frequency sweep period;

[0081] Step 4.5: Recursively update the beat frequency estimate used for demodulation:

[0082]

[0083] Step 4.6: Use the updated version The baseband beat frequency signal of the m-th sweep cycle is dynamically demodulated and the phase is recalculated and updated. .

[0084] In a preferred embodiment of the frequency-modulated continuous wave radar vibration displacement estimation method based on dynamic demodulation, in step 5, the updated phase is... Phase unrolling of the sequence:

[0085]

[0086] in: For phase expansion.

[0087] In a preferred embodiment of the frequency-modulated continuous wave radar vibration displacement estimation method based on dynamic demodulation, in step 6, the phase is converted into a vibration displacement sequence along the target line-of-sight direction.

[0088] The vibration displacement is obtained.

[0089] In a preferred embodiment of the frequency-modulated continuous wave radar vibration displacement estimation method based on dynamic demodulation, in step 5, the phase unrolling eliminates the discontinuity caused by phase wrapping.

[0090] A system for performing the method includes:

[0091] The acquisition unit uses a fixed-frequency continuous-wave radar to acquire echo signals from the surface of a vibrating object;

[0092] The processing unit amplifies, down-converts, and low-pass filters the echo signal, converting it into a baseband beat frequency signal, forming a two-dimensional data matrix consisting of the number of fast-time sampling points N and the number of slow-time sweeps M. , and ;

[0093] The estimation unit performs zero-fill fast Fourier transform on the baseband beat frequency signal of the first sweep cycle and calculates the phase estimate of the first sweep cycle based on the maximum likelihood phase estimator.

[0094] Update unit, for the first The baseband beat frequency signal of one sweep cycle, Perform dynamic demodulation and update the phase to obtain the updated phase sequence;

[0095] Phase unpacking unit performs phase unpacking on the updated phase sequence;

[0096] The displacement calculation unit converts the phase into a vibration displacement sequence along the target's line of sight.

[0097] A computer storage medium including computer instructions that, when run on a computer, cause the computer to perform the method.

[0098] An electronic device, the electronic device comprising:

[0099] Memory, processor, and computer programs stored in memory and executable on the processor, wherein,

[0100] The processor implements the method when executing the program.

[0101] In one embodiment, a fixed monostation frequency-modulated continuous wave radar is used to acquire the target surface echo signal. This signal is then amplified, down-converted, and low-pass filtered to obtain a two-dimensional baseband beat frequency signal. First, a zero-filling fast Fourier transform is performed on the first sweep cycle, and the beat frequency is estimated within the target range gate. An initial phase is obtained based on a maximum likelihood phase estimator. Subsequently, the phase difference between adjacent sweeps is calculated in slow time, and this phase difference is mapped to a beat frequency correction. The demodulated beat frequency is then recursively updated, and dynamic demodulation is performed on each sweep cycle to obtain a continuous phase sequence. After phase expansion of the phase sequence, the phase is converted into vibration displacement along the target's line-of-sight direction, achieving subwavelength-level reconstruction of minute vibration displacement. This method eliminates the need for computationally intensive high-resolution beat frequency estimation algorithms and can suppress phase accumulation errors and phase jumps under conditions of slowly varying beat frequencies or low signal-to-noise ratios, improving displacement estimation accuracy and robustness.

[0102] In one embodiment, this disclosure provides a high-precision method for estimating small vibration displacements using frequency-modulated continuous wave radar based on dynamic demodulation, the method comprising the following steps:

[0103] Step 1: Use a fixed frequency modulated continuous wave radar to collect echo signals from the surface of the vibrating object;

[0104] Step 2: Amplify, downconvert, and low-pass filter the echo signal received by the frequency modulated continuous wave radar to convert it into a baseband beat frequency signal, forming a two-dimensional data matrix consisting of the number of fast-time sampling points N and the number of slow-time sweeps M.

[0105] Step 3: Apply zero-filling fast Fourier transform to the baseband beat frequency signal of the first sweep cycle, and calculate the phase estimate of the first sweep cycle based on the maximum likelihood phase estimator.

[0106] Step 4: For the first The baseband beat frequency signal of one sweep cycle ( Perform dynamic demodulation;

[0107] Step 5: Perform phase unrolling on the updated phase sequence;

[0108] Step 6: Convert the phase into a vibration displacement sequence in the target line of sight direction.

[0109] The high-precision micro-vibration displacement estimation method based on dynamic demodulation frequency-modulated continuous wave radar, in step 1, involves a fixed frequency-modulated continuous wave radar with a single-transmitter, single-receiver structure, installed facing the vibrating object (the object vibrates along the radar's line of sight), and the radar transmission frequency is set. sampling frequency ,bandwidth Frequency sweep cycle And collect beat frequency echo signals.

[0110] The high-precision micro-vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation, in step 2, involves amplifying, down-converting, and low-pass filtering the echo signal received by the microwave radar to form a two-dimensional baseband beat frequency signal composed of the number of fast-time sampling points N and the number of slow-time frequency sweeps M. ( and ).

[0111] The high-precision micro-vibration displacement estimation method based on dynamic demodulation frequency-modulated continuous wave radar, step 3 includes,

[0112] Step 3.1: After performing a zero-filled Fast Fourier Transform on the baseband beat frequency signal of the first sweep cycle, search for spectral peaks near the target range gate to obtain the beat frequency estimate for the first sweep cycle. ;

[0113] Step 3.2: Based on the maximum likelihood phase estimator:

[0114]

[0115] in: For the first Phase estimate for each sweep cycle, This is the baseband beat frequency signal. To increase the number of sampling points in a fast time, For the first Beat frequency estimate for each sweep cycle;

[0116] The phase estimate for the first sweep cycle can be calculated as follows: ;

[0117] Step 3.3 Set the updated phase estimate for the first sweep cycle to be [value]. .

[0118] The high-precision micro-vibration displacement estimation method based on dynamic demodulation frequency-modulated continuous wave radar, step 4 includes,

[0119] Step 4.1: For the m-th sweep frequency echo ( Repeat steps 4.2 through 4.6 below;

[0120] Step 4.2: Estimate the initial beat frequency estimate for the m-th sweep cycle. Based on this value, a phase estimate is calculated using the maximum likelihood phase estimator. ;

[0121] Step 4.3: Calculate the phase difference between adjacent sweep cycles:

[0122]

[0123] Step 4.4: Calculate the beat frequency correction:

[0124]

[0125] in: For the sweep bandwidth, The center wavelength, At the speed of light, This is the frequency sweep period;

[0126] Step 4.5: Recursively update the beat frequency estimate used for demodulation:

[0127]

[0128] Step 4.6: Use the updated version The baseband beat frequency signal of the m-th sweep cycle is dynamically demodulated and the phase is recalculated and updated. .

[0129] In the aforementioned high-precision micro-vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation, step 5 involves updating the phase obtained in step 4. Phase unrolling of the sequence:

[0130]

[0131] in: For phase expansion.

[0132] In the aforementioned high-precision micro-vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation, step 6 involves converting the phase into a vibration displacement sequence along the target's line-of-sight direction.

[0133]

[0134] Ultimately, the vibration displacement can be obtained. Example 1

[0135] This disclosure provides a high-precision method for estimating small vibration displacements using frequency-modulated continuous wave radar based on dynamic demodulation. The method includes the following steps:

[0136] Step 1: Use as follows Figure 2 The fixed-frequency continuous-wave radar shown collects echo signals from the surface of a vibrating object. The radar employs a single-transmitter, single-receiver structure, installed facing the vibrating object (which vibrates along the radar's line-of-sight). The radar's transmission frequency is set. sampling frequency ,bandwidth Frequency sweep cycle And collect beat frequency echo signals.

[0137] Step 2: Amplify, down-convert, and low-pass filter the echo signal received by the microwave radar to form a two-dimensional baseband beat frequency signal. .

[0138] Step 4: For the first The baseband beat frequency signal of one sweep cycle ( Perform dynamic demodulation;

[0139] Step 5: Perform phase unrolling on the updated phase sequence;

[0140] Step 6: Convert the phase into a vibration displacement sequence in the target line of sight direction.

[0141] The displacement estimation results for vibration displacement being a single sine wave are as follows: Figure 3 As shown, it has good displacement estimation results; the displacement estimation error of the vibration displacement as a single sine wave is as follows: Figure 4 As shown, it exhibits a small estimation error. To demonstrate the robustness of the proposed method, an experiment was conducted with multisine vibration displacements. The displacement estimation results for multisine vibration displacements are shown below. Figure 5 As shown, it has good displacement estimation results; the displacement estimation error of the vibration displacement is multi-sinusoidal, as shown in the figure. Figure 6 As shown, it has a small displacement estimation error.

[0142] Furthermore, traditional FMCW radar vibration measurement methods typically demodulate all sweep cycles using a fixed beat frequency. If the initial beat frequency estimation is flawed, or if the target distance changes slightly due to vibration, causing the true beat frequency to drift slowly over a longer time interval, the demodulated phase will generate an error that accumulates linearly over time. When this error exceeds ± This can cause phase jumps, severely distorting the displacement reconstruction results. This invention, however, calculates the phase difference between adjacent sweep cycles in real time. And based on physical relationships ( This is precisely mapped to a beat frequency correction value. This mechanism enables the demodulation beat frequency to be updated recursively. The demodulation frequency dynamically tracks the changing trend of the actual beat frequency, fundamentally suppressing the generation of phase accumulation error and effectively inhibiting phase jump phenomena.

[0143] Secondly, this dynamic demodulation process does not rely on computationally complex high-resolution beat frequency estimation algorithms (such as Chirp-Z transform). The initial beat frequency only needs to be roughly obtained within the target range gate using a zero-filled FFT, and the subsequent accuracy is continuously improved by the phase feedback loop. This not only significantly reduces the overall computational burden but also enhances the robustness of the algorithm under low signal-to-noise ratio conditions—because phase information still has high sensitivity at low SNR, and the differential characteristics of the phase difference can effectively suppress common-mode noise.

[0144] Furthermore, a high-precision initial phase is extracted using a maximum likelihood phase estimator, and the phase is re-demodulated after each beat frequency update to obtain a more accurate current phase, forming a closed-loop optimization process of "estimation – feedback – correction – re-estimation". This process ensures the continuity and accuracy of the phase sequence, providing a foundation for subsequent phase unfolding and subwavelength shift conversion. This provides a reliable foundation.

[0145] In summary, this dynamic demodulation mechanism cleverly transforms traditional open-loop demodulation into a closed-loop adaptive system by using phase evolution information in reverse for beat frequency correction. While ensuring low computational complexity, it effectively solves the phase distortion problem in practical scenarios such as slowly changing beat frequency and low signal-to-noise ratio, and achieves high-precision and highly robust estimation of small vibration displacements.

[0146] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation, characterized in that, Includes the following steps: Step 1: Use a fixed frequency modulated continuous wave radar to collect echo signals from the surface of the vibrating object; Step 2: Amplify, down-convert, and low-pass filter the echo signal to convert it into a baseband beat frequency signal, forming a two-dimensional data matrix consisting of the number of fast-time sampling points N and the number of slow-time sweeps M. , and ; Step 3: Apply zero-filling fast Fourier transform to the baseband beat frequency signal of the first sweep cycle, and calculate the phase estimate of the first sweep cycle based on the maximum likelihood phase estimator. Step 4: For the first The baseband beat frequency signal of one sweep cycle, Perform dynamic demodulation and update the phase to obtain the updated phase sequence; Step 5: Perform phase unrolling on the updated phase sequence; Step 6: Convert the phase into a vibration displacement sequence in the target line of sight direction.

2. The vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation according to claim 1, characterized in that, Preferably, in step 1, the fixed frequency modulated continuous wave radar adopts a single-transmitter, single-receiver structure, with its installation direction facing the vibrating object. The object vibrates along the radar's line of sight, and the radar transmission frequency is set. sampling frequency ,bandwidth Frequency sweep cycle And collect echo signals.

3. The vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation according to claim 2, characterized in that, Step 3 includes, Step 3.1: After performing a zero-filled Fast Fourier Transform on the baseband beat frequency signal of the first sweep cycle, search for spectral peaks near the target range gate to obtain the beat frequency estimate for the first sweep cycle. ; Step 3.2: Based on the maximum likelihood phase estimator: ； in: For the first Phase estimate for each sweep cycle, This is the baseband beat frequency signal. To increase the number of sampling points in a fast time, For the first Beat frequency estimate for each sweep cycle; The calculated phase estimate for the first sweep cycle is... ; Step 3.3: Let the updated phase estimate for the first sweep cycle be... .

4. The vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation according to claim 1, characterized in that, Step 4 includes, Step 4.1: For the m-th sweep frequency echo, Repeat steps 4.2 through 4.6; Step 4.2: Estimate the initial beat frequency estimate for the m-th sweep cycle. Based on this value, a phase estimate is calculated using the maximum likelihood phase estimator. ; Step 4.3: Calculate the phase difference between adjacent sweep cycles: ； Step 4.4: Calculate the beat frequency correction: ； in: For the sweep bandwidth, The center wavelength, At the speed of light, This is the frequency sweep period; Step 4.5: Recursively update the beat frequency estimate used for demodulation: ； Step 4.6: Use the updated version The baseband beat frequency signal of the m-th sweep cycle is dynamically demodulated and the phase is recalculated and updated. .

5. The vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation according to claim 4, characterized in that, In step 5, the updated phase Phase unrolling of the sequence: ； in: For phase expansion.

6. The vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation according to claim 5, characterized in that, In step 6, the phase is converted into a vibration displacement sequence in the target line-of-sight direction: The vibration displacement is obtained.

7. The vibration displacement estimation method for frequency-modulated continuous wave radar based on dynamic demodulation according to claim 1, characterized in that, In step 5, the phase unwrapping eliminates the discontinuities caused by phase wrapping.

8. A system for performing the method as described in any one of claims 1 to 7, characterized in that, It includes: The acquisition unit uses a fixed-frequency continuous-wave radar to acquire echo signals from the surface of a vibrating object; The processing unit amplifies, down-converts, and low-pass filters the echo signal, converting it into a baseband beat frequency signal, forming a two-dimensional data matrix consisting of the number of fast-time sampling points N and the number of slow-time sweeps M. , and ; The estimation unit performs zero-fill fast Fourier transform on the baseband beat frequency signal of the first sweep cycle and calculates the phase estimate of the first sweep cycle based on the maximum likelihood phase estimator. Update unit, for the first The baseband beat frequency signal of one sweep cycle, Perform dynamic demodulation and update the phase to obtain the updated phase sequence; Phase unpacking unit performs phase unpacking on the updated phase sequence; The displacement calculation unit converts the phase into a vibration displacement sequence along the target's line of sight.

9. A computer storage medium, characterized in that, The storage medium includes computer instructions that, when executed on a computer, cause the computer to perform the method as described in any one of claims 1-7.

10. An electronic device, characterized in that, The electronic device includes: Memory, processor, and computer programs stored in memory and executable on the processor, wherein, When the processor executes the program, it implements the method as described in any one of claims 1-7.

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