Multi-reflection superposition enhanced microwave displacement measurement method and system

Abstract

The invention provides a multi-reflection superposition enhanced microwave displacement measurement method and system, and the method comprises the steps: S1, constructing a microwave multi-reflection propagation path, enabling a microwave radar to transmit electromagnetic waves to the microwave multi-reflection propagation path as a transmission signal, and receiving a corresponding echo signal; s2, extracting length change information of a microwave multi-reflection propagation path according to the echo signal; s3, establishing a linear superposition relation model between the total length of the microwave propagation path and respective displacements of W reflection surfaces in the microwave multi-reflection propagation path; w2; and S4, based on the linear superposition relation model, displacement information of the corresponding reflection surface is obtained and output. According to the invention, a larger phase variation can be obtained under the condition of small displacement or weak vibration, so that the measurement sensitivity is improved and the signal-to-noise ratio is improved.

Description

Technical Field

[0001] This invention belongs to the field of microwave sensing and precision measurement technology, specifically relating to a microwave displacement measurement method and system that enhances by multiple reflections. Background Technology

[0002] Microwave-based displacement measurement technology has attracted widespread attention due to its high integration, ease of installation, and strong environmental adaptability. These methods are widely used in fields such as vital sign monitoring, structural health monitoring, and remote acoustic sensing.

[0003] In recent years, research has made significant progress in improving anti-interference capabilities, measurement range, accuracy, and measurable range. However, existing microwave displacement measurement methods almost all rely on a single reflection path, focusing only on the direct echo from the target object. Fundamentally, these techniques achieve this by demodulating the phase shift of the reflected signal caused by the change in the microwave propagation path length due to target motion. In this traditional mode, measurement sensitivity is directly limited by the target's reflective cross-sectional area and vibration amplitude. For weak vibrations, such as micrometer-level displacement, or for measuring distant targets, the signal-to-noise ratio (SNR) is often limited.

[0004] Meanwhile, the wavelength of microwave signals, ranging from 1 mm to 1 m, is much greater than the surface roughness of most objects, making many objects highly reflective of microwaves. In real-world scenarios, multiple microwave reflections are unavoidable. Although some existing studies, such as non-line-of-sight imaging and through-wall radar, utilize wall reflections to redirect microwave paths, they typically assume the reflecting surface is stationary, using reflection alone to alter the propagation path, without considering the modulation effect of the reflecting surface's own motion on the path length.

[0005] Existing microwave displacement measurement techniques have significant limitations, the core issue being their near-complete reliance on single-reflection paths. This means current methods focus solely on the direct echo signal emitted from the radar and reflected back from the target surface in a single instance. The measurement principle relies on demodulating the phase shift caused by changes in the microwave propagation path length due to target motion. This single-reflection-based mechanism directly limits measurement sensitivity to the actual physical displacement amplitude of the target. For weak vibrations at the micrometer level or for distant, weakly reflective targets, the resulting path length changes are negligible, leading to a low signal-to-noise ratio (SNR) in the echo signal, making it difficult to meet the demands of high-precision micro-displacement measurements. Furthermore, while some non-line-of-sight (NLOS) detection techniques utilize microwave reflection characteristics, these methods typically assume the reflecting surface itself is stationary, using only the reflecting surface to alter the microwave propagation direction to detect targets with obstructed lines of sight. These techniques fail to consider or utilize the modulation effect of the reflecting surface's own motion on the microwave propagation path length. Therefore, they cannot achieve linear superposition of multiple target displacements at the physical signal transmission level, nor can they leverage multiple reflections to multiply the path length change and amplify weak vibration signals.

[0006] In non-contact displacement and vibration measurement based on microwave radar, existing technologies still face several unavoidable technical problems in practical engineering implementation, particularly in the areas of minute displacement measurement, multi-target collaborative sensing, and complex reflection environments. First, existing microwave displacement measurement methods are typically based on the single-reflection path assumption, which assumes that the radar-transmitted signal returns to the receiver after one reflection from the target surface, and the measurement result is only related to the displacement of that reflecting surface along the radar's line-of-sight. Under this assumption, when multiple reflecting surfaces exist simultaneously in the measurement scenario, or when electromagnetic waves undergo multiple reflections in space, the remaining reflection paths are often considered interference and suppressed or ignored. This approach makes it difficult for the measurement system to simultaneously reflect the motion information of multiple reflecting surfaces in a single measurement, limiting the application capability of microwave displacement measurement in multi-object synchronous sensing scenarios.

[0007] Secondly, in micro-displacement or weak vibration measurement scenarios, the propagation path length variation introduced by a single reflection path is limited, resulting in a small echo phase modulation. The measurement results are highly sensitive to system noise, phase noise, and environmental disturbances, easily leading to insufficient signal-to-noise ratio and consequently affecting measurement accuracy and stability. To address this issue, current engineering practices typically rely on increasing transmission power, extending coherent accumulation time, or using higher-performance hardware. However, these methods often introduce new problems such as increased system complexity, higher costs, or decreased real-time performance.

[0008] Third, in real-world measurement environments involving multiple reflections, although multiple reflections are common, existing technologies mostly treat them as a disadvantage, employing methods such as absorbing material coverage and geometric optimization to mitigate them. Even in some studies utilizing reflections for non-line-of-sight detection or special functions, it is typically assumed that the reflective surfaces other than the target remain stationary, thus only utilizing reflection to alter the electromagnetic wave propagation path, without considering the modulation effect of the reflective surface's own displacement on the propagation path. Therefore, when multiple reflective surfaces move simultaneously, existing methods struggle to uniformly model and effectively utilize the displacement contributions of each reflective surface in the multiple reflection path.

[0009] Fourth, for measurement requirements involving multiple targets or multiple reflective surfaces, existing solutions often rely on imaging, beamforming, or target-by-target scanning to separate different objects spatially or temporally before demodulating their displacement information. These methods not only result in complex system structures, but also significantly increase the complexity of the measurement process and algorithms as the number of targets increases or their motion spectra overlap, making it difficult to meet the engineering requirements of simplifying system structures and improving measurement robustness.

[0010] In summary, existing microwave displacement measurement technologies lack a unified technical solution that can describe the displacement contribution of each reflecting surface in the multiple reflection path from a mechanistic perspective and effectively utilize it in a single measurement, especially when faced with scenarios such as the prevalence of multiple reflections, the simultaneous movement of multiple reflecting surfaces, and the limited signal-to-noise ratio of micro-displacement measurements.

[0011] This technical problem urgently needs to be solved. Summary of the Invention

[0012] To address the shortcomings of existing technologies, the purpose of this invention is to provide a microwave displacement measurement method and system that enhances through multiple reflections.

[0013] A microwave displacement measurement method with enhanced multiple reflections provided by the present invention includes: Step S1: Construct a microwave multiple reflection propagation path, and have the microwave radar transmit electromagnetic waves as a transmission signal into the microwave multiple reflection propagation path, and receive the corresponding echo signals. Step S2: Extract the information on the change in the propagation path length of microwave multiple reflections based on the echo signal; Step S3: Establish a linear superposition model between the total length of the microwave propagation path and the displacements of the W reflecting surfaces in the microwave multiple reflection propagation path; W 2; Step S4: Based on the linear superposition relationship model, obtain and output the displacement information of the corresponding reflective surface.

[0014] Preferably, in step S1, the microwave multiple reflection propagation path includes multiple reflective surfaces, and the electromagnetic waves emitted by the microwave radar can be reflected multiple times by the reflective surfaces and then return to the receiving end of the microwave radar. The number of the reflective surfaces is greater than or equal to 2; All reflective surfaces are arranged parallel to each other.

[0015] Preferably, in step S2, the expression for the mixed echo signal and transmitted signal is:

[0016] in, This indicates the result obtained after mixing the received echo with the transmitted signal. Indicates the rapid intrapulse time; Represents a rectangular window function; Indicates the signal pulse width; Represents the imaginary unit; Indicates the starting frequency of linear frequency modulation; The slope of the linear frequency modulation (LFM) is represented. Represents the natural constant. Indicates the reflection coefficient; Indicates the total path length of microwave propagation; Represents the speed of light; The complex reflection information is obtained by mixing the echo signal with the transmitted signal using Fourier transform; the complex reflection information reflects the change of microwave propagation path length over time.

[0017] in, Represents complex reflection information. Indicates the initial length of the path; Indicates slow time; This indicates the phase of the intermediate frequency signal obtained after mixing the received echo with the transmitted signal; The relationship between the microwave propagation path length and the displacement of the reflecting surface is expressed as:

[0018] in, This indicates the change in microwave path length. Indicates the amount of change.

[0019] Preferably, in step S3, the mathematical expression of the linear superposition relationship model is:

[0020] in, This represents the change in the length of the microwave propagation path; Represents the differential operator; This represents the projection of the microwave path length onto the direction perpendicular to the reflecting surface. This represents the projection of the microwave path length in a direction parallel to the reflecting surface. Indicates the microwave incident angle; Indicates the total number of reflective surfaces; Indicates the index of the reflecting surface; Indicates the first The displacement of a reflective surface.

[0021] Preferably, in step S3, when the displacement of each reflective surface is less than 10 mm, the mathematical expression of the linear superposition model is:

[0022] in, This represents the change in total path length, i.e., the change in the microwave propagation path length.

[0023] A microwave displacement measurement system with enhanced multiple reflections provided by the present invention includes: Module M1: Constructs a microwave multiple reflection propagation path, causes the microwave radar to transmit electromagnetic waves as a transmission signal into the microwave multiple reflection propagation path, and receives the corresponding echo signal; Module M2: Extracts information on the change in the propagation path length of microwaves after multiple reflections based on the echo signal; Module M3: Establishes a linear superposition model between the total length of the microwave propagation path and the displacements of the W reflecting surfaces in the microwave multiple reflection propagation path; W 2; Module M4: Based on the linear superposition relationship model, obtains and outputs the displacement information of the corresponding reflective surface.

[0024] Preferably, in module M1, the microwave multiple reflection propagation path includes multiple reflective surfaces, and the electromagnetic waves emitted by the microwave radar can be reflected multiple times by the reflective surfaces and then return to the receiving end of the microwave radar. The number of the reflective surfaces is greater than or equal to 2; All reflective surfaces are arranged parallel to each other.

[0025] Preferably, in module M2, the expression for the mixed echo signal and transmitted signal is:

[0026] in, This indicates the result obtained after mixing the received echo with the transmitted signal. Indicates the rapid intrapulse time; Represents a rectangular window function; Indicates the signal pulse width; Represents the imaginary unit; Indicates the starting frequency of linear frequency modulation; The slope of the linear frequency modulation (LFM) is represented. Represents the natural constant. Indicates the reflection coefficient; Indicates the total path length of microwave propagation; Represents the speed of light; The complex reflection information is obtained by mixing the echo signal with the transmitted signal using Fourier transform; the complex reflection information reflects the change of microwave propagation path length over time.

[0027] in, Represents complex reflection information. Indicates the initial length of the path; Indicates slow time; This indicates the phase of the intermediate frequency signal obtained after mixing the received echo with the transmitted signal; The relationship between the microwave propagation path length and the displacement of the reflecting surface is expressed as:

[0028] in, This indicates the change in microwave path length. Indicates the amount of change.

[0029] Preferably, in module M3, the mathematical expression of the linear superposition relationship model is:

[0030] in, This represents the change in the length of the microwave propagation path; Represents the differential operator; This represents the projection of the microwave path length onto the direction perpendicular to the reflecting surface. This represents the projection of the microwave path length in a direction parallel to the reflecting surface. Indicates the microwave incident angle; Indicates the total number of reflective surfaces; Indicates the index of the reflecting surface; Indicates the first The displacement of a reflective surface. It represents the product.

[0031] Preferably, in module M3, when the displacement of the reflective surface is less than 50 mm, the mathematical expression of the linear superposition model is:

[0032] in, This indicates the change in total path length.

[0033] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention establishes a linear superposition relationship between the change in the length of the received signal propagation path and the displacement of each reflecting surface in the multiple reflection path by constructing and utilizing a microwave multiple reflection propagation path. This allows for the simultaneous sensing of displacement information of multiple reflecting surfaces in a single measurement, overcoming the technical limitations of traditional microwave displacement measurement that relies on the assumption of single reflection and single target. In other words, by constructing and utilizing a microwave multiple reflection propagation path, this invention establishes a linear superposition relationship between the change in the equivalent propagation path length corresponding to the received signal and the displacement of each reflecting surface in the multiple reflection path. This allows for the simultaneous reflection of displacement information of multiple reflecting surfaces in a single measurement, avoiding the problems of requiring target-by-target measurement or relying on complex spatial separation methods in existing technologies.

[0034] 2. This invention transforms multiple reflections, which are interference factors that need to be suppressed or avoided in existing technologies, into a measurement resource that can be actively utilized. By rationally designing multiple reflection paths, the displacement of the same reflecting surface is accumulated multiple times in the propagation path, thereby significantly amplifying the change in the equivalent propagation path length and improving the sensitivity and signal-to-noise ratio of micro-displacement measurements. It is particularly suitable for displacement measurements under conditions of slight vibration or weak reflection. In other words, by causing electromagnetic waves to undergo multiple reflections on the same reflecting surface, this invention effectively amplifies the modulation effect of the reflecting surface displacement on the propagation path length. Compared with traditional single-reflection measurement methods, a larger phase change can be obtained under conditions of slight displacement or weak vibration, thereby improving measurement sensitivity and signal-to-noise ratio.

[0035] 3. When multiple reflective surfaces are displaced simultaneously, this invention utilizes the distinguishability of displacement signals in the frequency domain, time domain, or other characteristic domains to effectively separate and extract superimposed displacement signals. This achieves both multi-target measurement capability and system simplification without adding additional measurement channels. In other words, when multiple reflective surfaces are displaced in multiple reflection paths, the measurement signal obtained by this invention is a linear superposition of the displacement components of each reflective surface. That is, even when the displacements of each reflective surface are different in the frequency domain, time domain, or other characteristic domains, the superimposed signal is effectively separated and recovered, thereby achieving synchronous measurement of multiple targets without adding additional measurement channels.

[0036] 4. This invention uses the range resolution capability of microwave radar itself to assist in constraining and identifying multiple reflection paths, enabling the multi-reflection displacement superposition measurement method to be stably implemented in actual engineering environments. This reduces the uncertainty caused by multi-path aliasing and improves the reliability and repeatability of measurement results. In other words, this invention no longer regards multiple reflections as interference that needs to be avoided, but transforms them into usable measurement resources. This allows the method to naturally adapt to complex reflection environments, reduces dependence on absorbing materials, strict geometric layouts, or reflection suppression measures, and improves the applicability of the method in actual engineering environments.

[0037] 5. The technical solution of this invention does not rely on multi-radar coordination, complex imaging processing, or high-precision mechanical scanning structures. It can be implemented on the basis of existing microwave radar systems through software and geometric layout design. The system structure is simple, low-cost, and easy to deploy, and has good engineering feasibility and promotion value. In other words, this invention can be implemented based on existing microwave radar systems without the need for multi-radar coordination, complex mechanical scanning structures, or high-complexity imaging processing. The measurement task can be completed only through multiple reflection path designs and signal processing, which helps to reduce system costs and simplify deployment and maintenance processes.

[0038] 6. This invention is applicable to both single-target high-sensitivity displacement measurement and sensing scenarios with multiple reflective surfaces or multiple objects moving simultaneously. The reflective surfaces include both artificially set reflective structures and naturally existing object surfaces, and have good application flexibility and expansion potential. Attached Figure Description

[0039] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 A schematic flowchart of the microwave displacement measurement method enhanced by multiple reflections provided by the present invention; Figure 2 This is a geometric schematic diagram of the microwave multiple reflection propagation path provided by the present invention; wherein, ~ These represent the displacements of the four reflecting surfaces; Indicates the microwave incident angle; This represents the projection of the microwave path length in a direction parallel to the reflecting surface. Figure 3 This is a schematic diagram of the experimental test scenario provided by the present invention; Figure 4 The structural block diagram of the microwave displacement measurement system enhanced by multiple reflections provided by the present invention is shown. Detailed Implementation

[0040] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0041] The specific implementation scheme of the microwave displacement measurement method enhanced by multiple reflections proposed in this invention achieves high-precision displacement measurement by using a single microwave measuring instrument to utilize multiple microwave reflections; furthermore, the overall components and features of the microwave displacement measurement method and system enhanced by multiple reflections proposed in this invention are described.

[0042] This invention proposes a microwave displacement measurement method enhanced by multiple reflections. By constructing and analyzing the propagation path of electromagnetic waves through multiple reflections, the change in the equivalent propagation path length corresponding to the received signal is linearly superimposed with the displacement of each reflecting surface in the multiple reflection path. This enables the joint sensing of displacement information of multiple reflecting surfaces in a single measurement, and distinguishes and extracts the displacement components of each reflecting surface when certain conditions are met.

[0043] A microwave displacement measurement method with enhanced multiple reflections provided by the present invention includes: First, an electromagnetic wave signal is emitted towards the area to be measured using a microwave radar. At least one multi-reflection propagation path is constructed in space, containing two or more reflective surfaces. The electromagnetic wave signal is then reflected sequentially on these surfaces before returning to the radar receiver. These reflective surfaces can belong to different locations of the same object, or they can belong to multiple independent objects.

[0044] In some embodiments, multiple reflection propagation paths are formed by rationally arranging the spatial positions and orientations of the reflective surfaces, so that adjacent reflective surfaces meet the conditions for microwave reachability and effective reflection; in other embodiments, the reflective surfaces may be naturally existing structural surfaces or artificially set reflective structures, without requiring complex modifications to the measurement environment.

[0045] Secondly, during radar transmission and reception, echo signals returning along the multiple reflection propagation paths are acquired, and the corresponding propagation path length change information is extracted based on the echo signals. Since electromagnetic waves sequentially pass through multiple reflecting surfaces during propagation, the propagation path length change includes the superposition effect of the displacement of each reflecting surface on the path length modulation.

[0046] In this invention, by geometrically modeling the propagation path of multiple reflections, and under the condition that the target displacement amplitude is relatively small relative to the propagation distance, the change in the propagation path length is approximately represented as a linear combination of the displacement components of each reflecting surface along the corresponding incident direction in the path, thereby establishing a linear mapping relationship between the phase change of the received signal and the displacement of multiple reflecting surfaces.

[0047] Furthermore, when there is only one displaced reflecting surface in the multiple reflection propagation path, the change in the equivalent propagation path length introduced by the multiple reflections is amplified relative to the single reflection case, thereby improving the sensitivity and signal-to-noise ratio of micro-displacement measurement; when there are multiple displaced reflecting surfaces in the multiple reflection propagation path, the displacement signals of each reflecting surface will be linearly superimposed to jointly modulate the received signal.

[0048] Furthermore, when the displacement signals of multiple reflecting surfaces are distinguishable in the frequency domain, time domain, or other characteristic domains, the displacement components of different reflecting surfaces can be separated and recovered based on the received signals. For example, when the vibration frequencies of different reflecting surfaces do not overlap, the displacement components corresponding to each reflecting surface can be extracted through spectrum analysis or filtering.

[0049] Furthermore, the method of the present invention uses the range resolution capability of microwave radar to assist in the design and verification of multiple reflection propagation paths, thereby distinguishing the echo components corresponding to different reflection paths during the measurement process and ensuring that the displacement superposition relationship is valid within the effective path range.

[0050] Through the above steps, the present invention achieves joint sensing of displacement information of multiple reflective surfaces in multiple reflection paths without adding additional measurement channels or relying on multi-radar coordination or complex imaging processing, providing a new technical approach for multi-target displacement measurement and high signal-to-noise ratio measurement of micro-displacement.

[0051] Example 1: A microwave displacement measurement method enhanced by multiple reflections like Figure 1 As shown in the figure, this embodiment provides a microwave displacement measurement method enhanced by multiple reflections, the method including the following steps: Step 1: As Figure 2 As shown, a microwave multiple reflection propagation path is constructed. A microwave radar transmits a microwave signal to the area to be measured, and the microwave signal is reflected multiple times by multiple reflective surfaces during propagation before returning to the radar receiver, forming a microwave multiple reflection propagation path containing multiple reflective surfaces.

[0052] The reflective surface can be the surface of multiple independent vibrating objects, or it can be multiple reflective surfaces on the same object.

[0053] In some embodiments, the reflective surfaces can be arranged parallel to each other to ensure that the incident angle of microwaves on each reflective surface is basically the same, thereby forming a stable multiple reflection path.

[0054] In some embodiments, the number of reflective surfaces is greater than or equal to two, that is, two or more, and the number is not limited.

[0055] Step 2: Obtain the phase change signal caused by multiple reflection paths. The radar receives the echo signal after multiple reflections and demodulates the echo signal to obtain the phase change signal corresponding to the change in microwave propagation path length.

[0056] Microwave radar transmitted signals can be described as follows:

[0057] in, This indicates the transmitted signal of the microwave radar. Indicates the rapid intrapulse time; Represents a rectangular window function; Indicates the signal pulse width; Represents the imaginary unit; Indicates the starting frequency of linear frequency modulation; The slope of the linear frequency modulation (LFM) is represented. Indicates the initial phase; Represents the natural constant.

[0058] After mixing the received echo with the transmitted signal, the following is obtained:

[0059] In other words, will Approximately:

[0060] in, This indicates the result obtained after mixing the received echo with the transmitted signal. Represents the reflection coefficient; the symbol * indicates complex conjugate; Indicates the total path length of microwave propagation; Represents the speed of light; Performing a Fourier transform on it yields:

[0061] In other words, It can be expressed as:

[0062] in, Represents complex reflection information. Indicates the initial length of the path; This represents the center frequency of a linear frequency modulated continuous wave; This indicates the change in the total path length of microwave propagation; Indicates slow time; This indicates the phase of the intermediate frequency signal obtained after the received echo is mixed with the transmitted signal.

[0063] Specifically, for a single reflecting target, the signal refers to the complex reflection information of that target. For multiple reflections proposed in this invention, the complex reflection information is the equivalent reflection information that returns to the radar after being reflected by multiple targets.

[0064] Its phase change signal reflects the change in microwave propagation path length over time, and this path length change is caused by the joint displacement of all surfaces involved in reflection in the multiple reflection paths, that is:

[0065] in, This indicates the change in microwave path length. Indicates the amount of change.

[0066] In some embodiments, the radar may be a frequency modulated continuous wave radar, i.e., an FMCW radar, which extracts phase information by performing a Fourier transform on the intermediate frequency signal.

[0067] In some embodiments, other microwave measurement systems with phase measurement capabilities may also be used.

[0068] Step 3: Establish a displacement superposition relationship based on the multiple reflection paths. Based on the geometric relationship of the microwave multiple reflection propagation paths, establish the correspondence between the change in propagation path length and the displacement of each reflecting surface:

[0069] in, This represents the change in the length of the microwave propagation path; Represents the differential operator; This represents the projection of the microwave path length onto the direction perpendicular to the reflecting surface. This represents the projection of the microwave path length in a direction parallel to the reflecting surface. Indicates the microwave incident angle; Indicates the total number of reflective surfaces; Indicates the index of the reflecting surface; Indicates the first The displacement of a reflective surface.

[0070] When the displacement of each reflecting surface is less than 10 mm, the change in the total propagation path length caused by the multiple reflections can be approximately represented as the linear superposition of the displacements of each reflecting surface. That is, the change in path length caused by the multiple reflections is proportional to the sum of the displacements of each reflecting surface, and does not introduce nonlinear distortion.

[0071] In other words, in this situation, The expression is:

[0072] Furthermore, when multiple reflecting surfaces belong to the same vibrating object and have the same vibration displacement, multiple reflections will have a superimposed amplification effect on the vibration displacement, thereby improving the displacement measurement sensitivity and signal-to-noise ratio.

[0073] In some embodiments, the incident angle of each reflecting surface in the multiple reflection path can be designed to be a small angle to further enhance the sensitivity of the path length change to displacement.

[0074] In some embodiments, the displacement of a reflective surface is only included in the superposition calculation when the reflective surface can effectively reflect microwave signals; surfaces with geometric mismatch, weak reflection, or that are blocked are not included in the superposition.

[0075] Step 4: Extract and separate the vibration components from the displacement superposition signal. Perform time-domain or frequency-domain analysis on the displacement superposition signal, and extract or separate each displacement component according to the vibration characteristics of different vibration objects. When the vibration signals corresponding to multiple reflecting surfaces are distinguishable in the frequency domain, each vibration component can be extracted separately by frequency domain filtering.

[0076] In some embodiments, signal processing methods such as blind source separation and adaptive filtering are further combined to improve the ability to separate multiple vibration components.

[0077] Example 2: A microwave displacement measurement system enhanced by multiple reflections and superposition This embodiment provides a microwave displacement measurement system enhanced by multiple reflection superposition. The system can execute the microwave displacement measurement method enhanced by multiple reflection superposition described in Embodiment 1, and is used to obtain the superposition measurement results of the displacements of multiple reflecting surfaces, or to enhance the measurement of displacements of the same object under multiple reflection paths. The system includes at least: The system includes a microwave measurement module, a reflection path construction module, a signal processing module, a displacement superposition and calculation module, and a displacement analysis output module.

[0078] The above modules work collaboratively in a chain of "path construction—echo acquisition—signal extraction—superposition calculation—analysis output", including: The reflection path construction module is used to determine and fix the geometry and reflection conditions of multiple reflections, and provides the corresponding path model parameters to the displacement superposition solution module as the solution basis; The microwave measurement module transmits and receives echoes under this path condition, and transmits the sampled echo data to the signal processing module; The signal processing module extracts the phase or equivalent path length change from the echo data and outputs it to the displacement superposition solution module. The displacement superposition solution module combines the path model to map phase / path changes into displacement superposition measurement results or enhanced displacement results of the same object under multiple reflection paths. Then, the displacement analysis output module performs time-domain / frequency-domain analysis, component extraction, and result presentation. The displacement analysis output module can also feed back the signal quality evaluation results to the signal processing module or microwave measurement module for adaptive adjustment of processing and measurement parameters, thereby forming a closed-loop collaboration.

[0079] (1) Microwave measurement module: The microwave measurement module is used to transmit microwave signals to the area to be measured and to receive echo signals after multiple reflections.

[0080] In this embodiment, the microwave measurement module includes a microwave transmitting unit and a microwave receiving unit, which can be integrated into the same microwave radar device to realize the transmission and echo reception of microwave signals.

[0081] In some embodiments, the microwave measurement module employs a frequency modulated continuous wave radar, i.e., an FMCW radar, to extract phase information from the intermediate frequency signal.

[0082] In some embodiments, the microwave measurement module may also employ other continuous wave or pulse microwave measurement systems with phase measurement capabilities.

[0083] In some embodiments, the microwave measurement module can be configured as a single-station structure or a distributed transceiver structure.

[0084] (2) Reflection path construction module: The reflection path construction module is used to construct multiple reflection propagation paths of microwave signals formed between multiple reflective surfaces, so that the displacement of multiple reflective surfaces works together to change the length of microwave propagation path.

[0085] In this embodiment, the reflection path construction module may include multiple reflective surfaces or reflective structures, which are arranged between the microwave measurement module and the object under test, or arranged on the surface of the object under test.

[0086] In some embodiments, the reflective surface may be multiple surfaces of the object under test itself.

[0087] In some embodiments, the reflective surface may also be an additional auxiliary reflective structure used to enhance the probability of forming multiple reflection paths.

[0088] In some embodiments, the reflective surfaces may be configured to be parallel or approximately parallel to each other to ensure that the incident angle of microwaves on each reflective surface is basically consistent, thereby improving the stability of the displacement superposition relationship.

[0089] In some embodiments, the number, spacing, and spatial distribution of reflective surfaces can be adjusted according to the actual application scenario.

[0090] (3) Signal processing module: The signal processing module is used to process the echo signal received by the microwave measurement module and extract the phase change information corresponding to the change in microwave propagation path length. Based on this, the microwave propagation path length change information is calculated.

[0091] In this embodiment, the signal processing module is configured to demodulate, filter, and perform Fourier transform processing on the echo signal to obtain the phase change relationship of the echo signal over time.

[0092] In some embodiments, the signal processing module is deployed inside the microwave measurement module to achieve local real-time processing.

[0093] In some embodiments, the signal processing module is deployed on an external computing device to receive and process echo data via wired or wireless means.

[0094] In some embodiments, the signal processing module performs noise reduction, phase unrolling, or drift compensation processing on the phase signal.

[0095] (4) Displacement superposition solution module, namely, displacement solution module enhanced by multiple reflection superposition: The displacement superposition solution module is used to convert the phase change information into the propagation path length change caused by the displacement of multiple reflective surfaces based on the multiple reflection propagation path model, and to establish the superposition relationship between the path length change and the displacement of each reflective surface.

[0096] In this embodiment, the displacement superposition solution module is configured to represent the path length change caused by multiple reflections as a linear superposition of the displacements of each reflecting surface when the displacement of the reflecting surface is small.

[0097] In some embodiments, when multiple reflective surfaces belong to the same object under test and have the same displacement, the displacement superposition solution module can perform equivalent amplification solution on the displacement to improve measurement sensitivity and signal-to-noise ratio.

[0098] In some embodiments, the displacement superposition solution module can correct the superposition coefficient based on the incident angle information of the reflection path.

[0099] In some embodiments, geometrically mismatched, weakly reflective, or occluded reflective surfaces may be automatically or manually excluded from the solution.

[0100] (5) Displacement analysis output module: The displacement analysis output module is used to analyze the displacement signal output by the displacement superposition solution module and output the corresponding measurement results.

[0101] In this embodiment, the displacement analysis output module can perform time-domain analysis or frequency-domain analysis on the superimposed displacement signal to identify the displacement components corresponding to different reflecting surfaces or different vibrating objects.

[0102] In some embodiments, when different displacement components are distinguishable in the frequency domain, each displacement component can be extracted by frequency domain filtering.

[0103] In some embodiments, the displacement analysis output module may further employ algorithms such as blind source separation and adaptive filtering to improve the displacement component separation capability.

[0104] In some embodiments, the displacement analysis output module can output the displacement results in the form of curves, spectra, or numerical values, or send them to a host computer, monitoring platform, or storage unit.

[0105] (6) Optional embodiments of system deployment and combination: In some embodiments, the microwave measurement module, signal processing module and displacement superposition calculation module can be integrated into the same device to form an integrated displacement measurement device.

[0106] In some embodiments, the modules described above can also be deployed in a distributed manner and work together through network connections.

[0107] In some embodiments, the system can be used for parallel displacement superposition measurement of multiple objects under test, or for high-sensitivity displacement measurement of a single object under multiple reflection paths.

[0108] The present invention also provides a microwave displacement measurement system enhanced by multiple reflection superposition. The microwave displacement measurement system enhanced by multiple reflection superposition can be implemented by executing the process steps of the microwave displacement measurement method enhanced by multiple reflection superposition. That is, those skilled in the art can understand the microwave displacement measurement method enhanced by multiple reflection superposition as a preferred embodiment of the microwave displacement measurement system enhanced by multiple reflection superposition.

[0109] A microwave displacement measurement system with enhanced multiple reflections provided by the present invention includes: Module M1: Constructs a microwave multiple reflection propagation path, causes the microwave radar to transmit electromagnetic waves as a transmission signal into the microwave multiple reflection propagation path, and receives the corresponding echo signal; Module M2: Extracts information on the change in the propagation path length of microwaves after multiple reflections based on the echo signal; Module M3: Establishes a linear superposition model between the total length of the microwave propagation path and the displacements of the W reflecting surfaces in the microwave multiple reflection propagation path; W 2; Module M4: Based on the linear superposition relationship model, obtains and outputs the displacement information of the corresponding reflective surface.

[0110] Module M1 includes a microwave measurement module and a reflection path construction module; modules M2, M3 and M4 functionally correspond to the signal processing module, the displacement superposition calculation module and the displacement analysis output module.

[0111] This invention solves the problems of low sensitivity and poor signal-to-noise ratio in existing microwave displacement measurement technology for monitoring small displacements and weakly reflective targets. By utilizing the multiple reflections of microwaves between multiple reflective surfaces, the displacements of all reflective surfaces are linearly superimposed on the changes in the microwave propagation path, thereby achieving synchronous superposition measurement of the displacements of multiple targets. Furthermore, the multiplication effect of multiple reflections significantly improves the sensitivity and signal-to-noise ratio for measuring the small displacements of a single target. Note that techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0112] For ease of description, the connection relationships between the various modules or parts shown in the accompanying drawings are merely exemplary. Those skilled in the art can employ other equivalent connection relationships, as long as the various modules or parts can also achieve the functions of the technical solution of this application under such connection relationships. The embodiments disclosed in this application can be set according to different equivalent connection relationships, so the connection relationships shown in the accompanying drawings and related contents of the specification are only for illustration and should not be regarded as limitations.

[0113] The dimensions of each component shown in the accompanying drawings are arbitrary, and this application does not limit the specific dimensions of each component unless explicitly stated or described in the specification and drawings. To make the illustrations clearer, the dimensions of some components have been appropriately exaggerated or the corresponding proportions adjusted in the drawings.

[0114] Ordinal numbers such as “first” and “second” used in this application are for distinction and identification only and have no other meaning. Unless otherwise specified, they do not indicate a specific order or a specific relationship. For example, the term “first component” does not imply the existence of “second component”, nor does the term “second component” imply the existence of “first component”.

[0115] The singular forms of "a," "the," and "the" used in this application are intended to include both singular and plural forms, unless the context clearly indicates otherwise. "Multiple" or "a plurality" generally includes at least two or more. The term "and / or" used in this application is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Furthermore, the character " / " in this application generally indicates that the preceding and following related objects are in an "or" relationship.

[0116] The terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0117] The technical solutions provided in this application can be systems, methods, apparatus, and / or computer program products. Computer program products may include computer-readable storage media loaded with computer-readable program instructions for causing a processor to implement various aspects of this application. The microwave measuring instrument may be a product or apparatus including radar, transceiver, processor, and module. Related methods can also be extended to optical measuring devices and means, including vision and laser.

[0118] In some embodiments, this application also provides a computer device, apparatus, or terminal. The computer device, apparatus, or terminal includes a processor, memory, network interface, display screen, and input device connected via a system bus. The processor provides computing and control capabilities, and the memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The network interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements the various methods, processes, and steps disclosed in this application, or the processor executes the computer program to implement the functions of various modules or units in the embodiments disclosed in this application. The display screen may be a liquid crystal display screen or an electronic ink display screen, and the input device may be a touch layer covering the display screen, or a button, trackball, or touchpad mounted on a casing, or an external keyboard, touchpad, or mouse, etc.

[0119] For example, a computer program can be divided into one or more modules or units, which are stored in memory and can be executed by a processor to implement the technical solution of this application. These modules or units can be a series of computer program instruction segments capable of performing specific functions, which describe the execution process of the computer program in a device, apparatus, or terminal.

[0120] The aforementioned devices, equipment, or terminals may be computing devices such as desktop computers, laptops, mobile electronic devices, handheld computers, and cloud servers. Those skilled in the art should understand that the structures shown in the figures are merely block diagrams of some structures related to the present application and do not constitute a limitation on the devices, equipment, or terminals to which the present application is applied. Specific devices, equipment, or terminals may include more or fewer components than shown in the figures, or may combine certain components, or may have different component arrangements.

[0121] A processor can be a Central Processing Unit (CPU), or other general-purpose or special-purpose processors, microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The processor is the control center of the aforementioned devices, equipment, or terminals, connecting various parts of the device, equipment, or terminal through various interfaces and lines.

[0122] Memory is used to store computer programs, modules, and data. Processors implement various functions of devices, equipment, or terminals by running or executing computer programs and / or modules stored in memory, and by accessing data stored in memory. Memory can primarily include a program storage area and a data storage area. The program storage area can store the operating system and at least one application program required for a function, such as sound playback or image playback. The data storage area can store various types of data created according to applications, such as multimedia data, documents, and operation history. Furthermore, memory can include high-speed random access memory, as well as non-volatile memory, such as hard disks, RAM, plug-in hard disks, smart media cards (SMC), secure digital cards (SD cards), flash cards, disk storage devices, flash memory devices, or other volatile solid-state storage devices.

[0123] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the above-described methods. Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above.

[0124] Any references to memory, storage, database, or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), memory bus RAM (RDRAM), direct memory bus RAM (DRDRAM), and memory bus RAM (RDRAM), etc.

[0125] The modules and units integrated into the aforementioned devices or terminal equipment, if implemented as software functional units and sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the various methods disclosed in this application can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the aforementioned methods. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. Computer-readable media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content contained in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction.

[0126] In some embodiments, the various methods, processes, modules, apparatuses, devices, or systems disclosed in this application may be implemented or performed in one or more processing means, such as a digital processor, an analog processor, a digital circuit designed for processing information, an analog circuit designed for processing information, a state machine, a computing device, a computer, and / or other means for electronically processing information. The one or more processing means may include one or more means for performing some or all of the operations of the method in response to instructions electronically stored on an electronic storage medium. The one or more processing means may include one or more means configured by hardware, firmware, and / or software specifically designed for performing one or more operations of the method. The above descriptions are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and inventive concept of this application, should be covered within the scope of protection of this application.

[0127] Implementations of this application can be carried out in hardware, firmware, software, or various combinations thereof, and can also be implemented as instructions stored on a machine-readable medium that can be read and executed using one or more processing devices. In some implementations, the machine-readable medium may include various mechanisms for storing and / or transmitting information in a machine-readable, e.g., computing device-readable form. For example, machine-readable storage media may include read-only memory, random access memory, disk storage media, optical storage media, flash memory devices, and other media for storing information, and machine-readable transmission media may include various forms of propagating signals and other media for transmitting information. While firmware, software, routines, or instructions may be described in the foregoing disclosure from the perspective of specific exemplary aspects and implementations of performing certain actions, it will be apparent that such descriptions are for convenience only and that such actions are actually generated by machine equipment, computing devices, processing devices, processors, controllers, or other means or machines that execute firmware, software, routines, or instructions. The propagating signals include: carrier waves, infrared signals, and digital signals.

[0128] In the claims and description of this application, the modules used to perform the specified functions, or modules described using functional features, are intended to cover any manner in which the function can be performed, such as: combinations of circuit elements performing the function, software, hardware, and combinations of software and hardware used to perform or implement the function, or any form of software, firmware, code, and their combination with suitable circuitry or other means. The functions provided by various modules are combined in the manner claimed in the claims, and therefore it should be considered that any module, component, or element that can provide these functions is equivalent to or equivalent to the module defined in the claims. Based on the principle of equivalent circuit transformation, the circuit structures of some embodiments in this application can also be changed or modified, for example, changing a current source to a voltage source, or a series structure to a parallel structure, thereby obtaining more diverse embodiments, but all such changes and modifications fall within the scope of this application.

[0129] This specification uses examples to disclose this application, one or more of which are described or illustrated in the specification and accompanying drawings. Each example is provided for the purpose of explaining this application and not for limiting it. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to this application without departing from the scope or spirit of this application. For example, a feature illustrated or described as part of one embodiment may be used with another embodiment to obtain a further embodiment. Therefore, it is intended that this application cover modifications and variations made within the scope of the appended claims and their equivalents. The above descriptions are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any technical solutions that can be obtained by those skilled in the art based on the concept of this application and on the basis of the prior art through logical analysis, reasoning, or limited experimentation, or any changes or substitutions that can be easily conceived, should be covered within the scope of protection of this application.

[0130] Those skilled in the art will understand that, besides implementing the system and its various devices, modules, and units provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices, modules, and units of this invention function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices, modules, and units provided by this invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices, modules, and units for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0131] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A microwave displacement measurement method enhanced by multiple reflections and superposition, characterized in that, include: Step S1: Construct a microwave multiple reflection propagation path, and have the microwave radar transmit electromagnetic waves as a transmission signal into the microwave multiple reflection propagation path, and receive the corresponding echo signals. Step S2: Extract the information on the change in the propagation path length of microwave multiple reflections based on the echo signal; Step S3: Establish a linear superposition model between the total length of the microwave propagation path and the displacements of the W reflecting surfaces in the microwave multiple reflection propagation path; W 2; Step S4: Based on the linear superposition relationship model, obtain and output the displacement information of the corresponding reflective surface.

2. The microwave displacement measurement method enhanced by multiple reflections according to claim 1, characterized in that, In step S1, the microwave multiple reflection propagation path includes multiple reflective surfaces, and the electromagnetic waves emitted by the microwave radar can be reflected multiple times by the reflective surfaces and then return to the receiving end of the microwave radar. The number of the reflective surfaces is greater than or equal to 2; All reflective surfaces are arranged parallel to each other.

3. The microwave displacement measurement method enhanced by multiple reflections according to claim 1, characterized in that, In step S2, the expression for the mixed echo signal and transmitted signal is: in, This indicates the result obtained after mixing the received echo with the transmitted signal. Indicates the rapid intrapulse time; Represents a rectangular window function; Indicates the signal pulse width; Represents the imaginary unit; Indicates the starting frequency of linear frequency modulation; The slope of the linear frequency modulation (LFM) is represented. Represents the natural constant. Indicates the reflection coefficient; Indicates the total path length of microwave propagation; Represents the speed of light; The complex reflection information is obtained by mixing the echo signal with the transmitted signal using Fourier transform; the complex reflection information reflects the change of microwave propagation path length over time. in, Represents complex reflection information. Indicates the initial length of the path; Indicates slow time; This indicates the phase of the intermediate frequency signal obtained after mixing the received echo with the transmitted signal; The relationship between the microwave propagation path length and the displacement of the reflecting surface is expressed as: in, This indicates the change in microwave path length. Indicates the amount of change.

4. The microwave displacement measurement method enhanced by multiple reflections according to claim 3, characterized in that, In step S3, the mathematical expression of the linear superposition relationship model is: in, This represents the change in the length of the microwave propagation path; Represents the differential operator; This represents the projection of the microwave path length onto the direction perpendicular to the reflecting surface. This represents the projection of the microwave path length in a direction parallel to the reflecting surface. Indicates the microwave incident angle; Indicates the total number of reflective surfaces; Indicates the index of the reflecting surface; Indicates the first The displacement of a reflective surface.

5. The microwave displacement measurement method enhanced by multiple reflections according to claim 3, characterized in that, In step S3, when the displacement of the reflective surface is less than 10 mm, the mathematical expression of the linear superposition model is: in, This represents the change in the length of the microwave propagation path.

6. A microwave displacement measurement system enhanced by multiple reflections and superposition, characterized in that, include: Module M1: Constructs a microwave multiple reflection propagation path, causes the microwave radar to transmit electromagnetic waves as a transmission signal into the microwave multiple reflection propagation path, and receives the corresponding echo signal; Module M2: Extracts information on the change in the propagation path length of microwaves after multiple reflections based on the echo signal; Module M3: Establishes a linear superposition model between the total length of the microwave propagation path and the displacements of the W reflecting surfaces in the microwave multiple reflection propagation path; W 2; Module M4: Based on the linear superposition relationship model, obtains and outputs the displacement information of the corresponding reflective surface.

7. The microwave displacement measurement system enhanced by multiple reflections according to claim 6, characterized in that, In module M1, the microwave multiple reflection propagation path includes multiple reflective surfaces, and the electromagnetic waves emitted by the microwave radar can be reflected multiple times by the reflective surfaces and then return to the receiving end of the microwave radar. The number of the reflective surfaces is greater than or equal to 2; All reflective surfaces are arranged parallel to each other.

8. The microwave displacement measurement system enhanced by multiple reflections according to claim 6, characterized in that, In module M2, the expression for the mixed echo signal and transmitted signal is: in, This indicates the result obtained after mixing the received echo with the transmitted signal. Indicates the rapid intrapulse time; Represents a rectangular window function; Indicates the signal pulse width; Represents the imaginary unit; Indicates the starting frequency of linear frequency modulation; The slope of the linear frequency modulation (LFM) is represented. Represents the natural constant. Indicates the reflection coefficient; Indicates the total path length of microwave propagation; Represents the speed of light; The complex reflection information is obtained by mixing the echo signal with the transmitted signal using Fourier transform; the complex reflection information reflects the change of microwave propagation path length over time. in, Represents complex reflection information. Indicates the initial length of the path; Indicates slow time; This indicates the phase of the intermediate frequency signal obtained after mixing the received echo with the transmitted signal; The relationship between the microwave propagation path length and the displacement of the reflecting surface is expressed as: in, This indicates the change in microwave path length. Indicates the amount of change.

9. The microwave displacement measurement system enhanced by multiple reflections according to claim 8, characterized in that, In module M3, the mathematical expression for the linear superposition model is: in, This represents the change in the length of the microwave propagation path; Represents the differential operator; This represents the projection of the microwave path length onto the direction perpendicular to the reflecting surface. This represents the projection of the microwave path length in a direction parallel to the reflecting surface. Indicates the microwave incident angle; Indicates the total number of reflective surfaces; Indicates the index of the reflecting surface; Indicates the first The displacement of a reflective surface.

10. The microwave displacement measurement system enhanced by multiple reflections according to claim 8, characterized in that, In module M3, when the displacement of the reflective surface is less than 10 mm, the mathematical expression of the linear superposition model is: in, This represents the change in the length of the microwave propagation path.

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