High-precision millimeter-wave radar ranging method and device based on multi-dimensional anti-interference mechanism

Abstract

This application provides a high-precision millimeter-wave radar ranging method and apparatus based on a multi-dimensional anti-interference mechanism, relating to the field of millimeter-wave radar ranging technology. The method includes: mixing the echo signal with the transmitted signal to obtain a beat intermediate frequency (IF) signal; performing matching processing on the beat IF signal using a phase coding sequence to identify its own echo signal and interference signals based on coding correlation; identifying and suppressing interference components in the matched signal to obtain a purified beat signal; obtaining a coarse distance to the target object based on the frequency information of the purified beat signal, and obtaining a fine distance increment based on the phase information corresponding to the target object; combining the coarse and fine distance increments to obtain the target object's distance information. Thus, by constructing an anti-interference system that coordinates the frequency domain, coding domain, and signal processing domain, high-precision ranging is achieved while effectively suppressing various types of interference and fully preserving the target echo phase information.

Description

Technical Field

[0001] This application relates to the field of millimeter-wave radar ranging technology, and in particular to a high-precision millimeter-wave radar ranging method and device based on a multi-dimensional anti-interference mechanism. Background Technology

[0002] Millimeter-wave radar is widely used in industrial precision measurement and vibration detection due to its non-contact measurement and all-weather operation characteristics. To obtain high-precision ranging results, a combination of frequency-modulated continuous wave (FMCW) coarse ranging and carrier phase fine ranging is usually used to achieve sub-millimeter accuracy.

[0003] However, with the increasing deployment density of radar equipment in the same frequency band, problems such as co-channel interference, pulse interference, and multipath interference in complex electromagnetic environments are becoming increasingly prominent. Most existing FMCW radars lack dedicated anti-jamming mechanisms or only use single methods (such as frequency hopping or filtering) for interference suppression, which have limited effectiveness in dealing with multiple types of interference. More importantly, anti-jamming processing often requires modifying or eliminating interference components in the received signal. If such operations are not handled properly, they can contaminate or destroy the phase information of the target echo, leading to a serious decrease or even failure of subsequent phase ranging accuracy.

[0004] Therefore, how to effectively suppress various interferences while fully preserving the phase information of the target echo to achieve high-precision ranging has become an urgent technical problem to be solved. Summary of the Invention

[0005] The purpose of this application is to provide a high-precision millimeter-wave radar ranging method and device based on a multi-dimensional anti-interference mechanism. By constructing an anti-interference system that coordinates the frequency domain, coding domain and signal processing domain, it can effectively suppress various types of interference while completely preserving the target echo phase information. This solves the coupling contradiction between anti-interference processing and high-precision phase ranging in complex electromagnetic environments, and achieves high-precision ranging.

[0006] This application provides a high-precision millimeter-wave radar ranging method based on a multi-dimensional anti-interference mechanism, including: The system receives an echo signal; the echo signal is the signal reflected by a composite modulated transmitted signal after passing through a target object; the composite modulated transmitted signal is obtained by superimposing a phase-coded sequence on a frequency-modulated continuous wave signal, and the sweep start frequency of the frequency-modulated continuous wave signal can vary during different sweep cycles; the echo signal is mixed with the transmitted signal to obtain a beat intermediate frequency signal, and the beat intermediate frequency signal is matched using the phase-coded sequence to identify its own echo signal and interference signals based on the coding correlation; interference components are identified and directionally suppressed on the matched signal to obtain a cleaned beat signal, and the phase information corresponding to the target object in the cleaned beat signal is retained during the interference suppression process; a coarse distance to the target object is obtained based on the frequency information of the cleaned beat signal, and a fine distance increment is obtained based on the phase information corresponding to the target object; the distance information of the target object is obtained by combining the coarse distance and the fine distance increment.

[0007] Optionally, the composite modulated transmission signal is generated in the following manner: dynamically selecting the operating frequency band based on the spectrum sensing results, controlling the frequency sweep start frequency of the frequency modulated continuous wave transmission signal to switch during the frequency hopping cycle, and synchronizing the frequency hopping switching time with the boundary of the frequency sweep cycle; obtaining a preset phase coding sequence, and superimposing the phase coding sequence on the frequency modulated continuous wave transmission signal to generate the composite modulated transmission signal.

[0008] Optionally, the step of dynamically selecting the working frequency band based on the spectrum sensing results includes: obtaining the interference level of each sub-band in the working frequency band within the frequency hopping decision period; and selecting the frequency point with the optimal signal-to-interference-plus-noise ratio from a preset set of frequency hopping frequency points as the working frequency for the next frequency hopping period based on the interference level of each sub-band.

[0009] Optionally, the phase coding sequence is a maximum length sequence greater than a preset code length; the step of superimposing the phase coding sequence on the frequency-modulated continuous wave transmitted signal to generate a composite modulated transmitted signal includes: mapping the phase coding sequence to a phase flip and superimposing it on the frequency-modulated continuous wave signal through a modulator to generate a composite modulated transmitted signal; wherein, the chip duration of the phase coding sequence is less than the beat signal period and greater than the carrier signal period.

[0010] Optionally, the step of identifying and directionally suppressing interference components in the matched signal to obtain a cleaned beat signal includes: performing time-frequency transformation on the matched signal; identifying the interference type according to a preset interference time-frequency feature template; adaptively setting a detection threshold in the distance spectrum using a constant false alarm rate detection algorithm; marking spectral components that exceed the threshold and do not belong to the target object as interference components; and directionally suppressing the interference components according to a preset mapping relationship between the identified interference type and the suppression strategy to obtain the cleaned beat signal.

[0011] Optionally, obtaining the coarse distance to the target object based on the frequency information of the purification beat signal and obtaining the fine distance increment based on the phase information corresponding to the target object includes: performing frequency analysis on the purification beat signal and obtaining the coarse distance based on the linear relationship between the beat frequency and the distance; extracting the phase information at the spectral peak corresponding to the target object in the purification beat signal, and obtaining the fine distance increment based on the relationship between the phase difference and the distance change between adjacent measurements or adjacent sweep cycles.

[0012] Optionally, obtaining the distance information of the target object by combining the coarse distance and the fine distance increment includes: determining the phase ambiguity period of the fine distance increment based on the coarse distance, and adding the coarse distance and the fine distance increment to obtain the distance information of the target object.

[0013] This application also provides a high-precision millimeter-wave radar ranging system based on a multi-dimensional anti-interference mechanism, including a module for executing any of the above-mentioned high-precision millimeter-wave radar ranging methods based on a multi-dimensional anti-interference mechanism.

[0014] This application also provides a computer program product, including a computer program / instructions that, when executed by a processor, implement the steps of the high-precision millimeter-wave radar ranging method based on a multi-dimensional anti-interference mechanism as described above.

[0015] This application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the high-precision millimeter-wave radar ranging method based on the multi-dimensional anti-interference mechanism described above.

[0016] This application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the high-precision millimeter-wave radar ranging method based on a multi-dimensional anti-interference mechanism as described above.

[0017] The high-precision millimeter-wave radar ranging method and apparatus based on a multi-dimensional anti-interference mechanism provided in this application firstly receives an echo signal; the echo signal is the signal after a composite modulated transmitted signal is reflected by a target object; the composite modulated transmitted signal is obtained by superimposing a phase-coded sequence on a frequency-modulated continuous wave signal, and the sweep start frequency of the frequency-modulated continuous wave signal is variable during different sweep cycles; then, the echo signal is mixed with the transmitted signal to obtain a beat intermediate frequency signal, and the beat intermediate frequency signal is matched using the phase-coded sequence to identify its own echo signal and interference signals based on the coding correlation; interference components are identified and directionally suppressed on the matched signal to obtain a purified beat signal, and the phase information corresponding to the target object in the purified beat signal is retained during the interference suppression process; finally, a coarse distance to the target object is obtained based on the frequency information of the purified beat signal, and a fine distance increment is obtained based on the phase information corresponding to the target object; combining the coarse distance and the fine distance increment, the distance information of the target object is obtained. Thus, by constructing an anti-interference system that coordinates the frequency domain, coding domain, and signal processing domain, the target echo phase information is fully preserved while effectively suppressing various types of interference. This solves the coupling contradiction between anti-interference processing and high-precision phase ranging in complex electromagnetic environments, and achieves high-precision ranging. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the architecture of the high-precision millimeter-wave radar ranging system based on a multi-dimensional anti-interference mechanism provided in this application; Figure 2 This is a flowchart illustrating the high-precision millimeter-wave radar ranging method based on a multi-dimensional anti-interference mechanism provided in this application. Figure 3 This is a schematic diagram of the timing relationship of the adaptive frequency hopping control provided in this application; Figure 4 This is a schematic diagram of phase-coded modulation and demodulation provided in this application; Figure 5 This is a complete flowchart of the multi-dimensional anti-interference processing provided in this application; Figure 6 This is a schematic diagram illustrating the principle of FMCW and phase-based combined ranging provided in this application; Figure 7 This is a schematic diagram of the structure of the electronic device provided in this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship. All actions involving the acquisition of signal information or data in this application are performed in accordance with the relevant data protection laws and policies of the country where the application is located and with authorization from the owner of the relevant device.

[0022] With the widespread deployment of millimeter-wave radar equipment in the 79GHz band, mutual interference within the same frequency band is becoming increasingly serious. Especially in industrial environments, multiple radar sensors often need to be densely deployed in limited spaces, and co-channel interference, multipath reflection, and electromagnetic noise significantly impact radar ranging performance. Existing technical solutions have the following main shortcomings: 1. Traditional FMCW radars lack dedicated anti-jamming mechanisms.

[0023] When receiving transmitted signals from other radars in the same frequency band, interference signals can generate false targets or raise the noise floor in the beat spectrum, severely affecting ranging accuracy and reliability. Especially in phase-based fine ranging mode, the contamination of phase estimation by interference signals will directly prevent the achievement of micrometer-level accuracy.

[0024] 2. Existing anti-interference solutions mostly employ a single technical means.

[0025] For example, relying solely on frequency hopping or using only signal processing-level filtering. Single methods have limited effectiveness when facing multiple types of interference. Specifically, different types of interference, such as co-frequency continuous wave interference, pulse interference, and multipath interference superposition, require different suppression strategies. Relying on a single method cannot stably maintain high-precision ranging performance under various interference scenarios.

[0026] 3. There is a coupling contradiction between anti-interference processing and high-precision phase ranging.

[0027] Anti-interference processing requires altering or eliminating interference components in the received signal, which inevitably affects the signal's amplitude and phase characteristics. Precision phase ranging demands high purity and consistency of the signal phase; any additional disturbance to the phase information will lead to a decrease in ranging accuracy. Current technologies typically address anti-interference and high-precision ranging as two separate problems, lacking a system-level joint design. This results in individually optimized anti-interference algorithms potentially introducing additional phase errors, thus reducing precision ranging performance. Conversely, system designs focused on accuracy often neglect the robustness requirements under interference environments.

[0028] To address the aforementioned technical problems in related technologies, this application provides a high-precision millimeter-wave radar ranging method based on a multi-dimensional anti-interference mechanism. This method enables a 79GHz continuous wave millimeter-wave radar to maintain a ranging accuracy of 0.02mm (20μm) while possessing strong robust suppression capabilities against various interference types, such as co-frequency interference, pulse interference, and multipath interference, in complex electromagnetic interference environments.

[0029] The core idea of ​​the technical solution in this application is to construct a three-dimensional joint anti-interference system of "frequency domain-coding domain-signal processing domain" and deeply integrate it with the joint ranging architecture of "FMCW coarse ranging + phase fine ranging" to achieve synergistic optimization of anti-interference and high precision. Figure 1 As shown, the overall system architecture includes the following core components: 1. 79GHz FMCW Transmitter Module: Based on a voltage-controlled oscillator (VCO) or phase-locked loop (PLL) frequency synthesizer, this module generates linear frequency modulated continuous wave signals in the 77-81GHz range. It supports programmable sweep bandwidth, sweep slope, and sweep period configuration.

[0030] 2. Adaptive Frequency Hopping Controller: Based on real-time spectrum sensing results, the system dynamically selects the optimal sweep start frequency and operating sub-band within the available bandwidth of the 79GHz band. The system pre-sets no fewer than 16 frequency hopping points, and the frequency hopping sequence is driven by a pseudo-random sequence generator. The frequency hopping period is precisely synchronized with the FMCW sweep period.

[0031] 3. Phase-coded modulator: Pseudo-random binary phase coding (PRBS) is superimposed on the FMCW linear frequency modulated signal. The transmitted signal within each sweep cycle is divided into multiple coded segments, and the phase of each segment is flipped by 0° or 180° according to the coding sequence. Different radars use different coding sequences (low cross-correlation), and the receiver achieves signal separation through matched filtering with its own coding.

[0032] 4. Echo Reception and Digitization Module: After the receiving antenna captures the echo signal, it is amplified by a low-noise amplifier (LNA) and mixed with the transmitted signal to generate a beat intermediate frequency (IF) signal. This IF signal is then digitized by a high-precision analog-to-digital converter (ADC). The ADC accuracy is no less than 16 bits, and the sampling rate is set according to the maximum beat frequency to ensure that the Nyquist sampling conditions are met.

[0033] 5. FMCW coarse ranging + phase fine ranging joint processor: First, windowed FFT is applied to the beat signal to obtain the range spectrum, and the peak value of the target echo is located. The coarse distance value of the target is calculated from the beat frequency (accuracy in millimeters). Then, the precise phase value at the peak value of the spectrum is extracted, and the phase difference is converted into a precise distance increment using the carrier wavelength (79GHz corresponds to approximately 3.8mm wavelength). Combined with the coarse ranging result, the 2π phase ambiguity is eliminated, and finally, a comprehensive ranging accuracy of 0.02mm is achieved.

[0034] 6. Adaptive Interference Detection and Suppression Module: This module comprises three layers of processing. The first layer is joint time-frequency domain interference feature identification, which analyzes the time-frequency distribution of beat signals using Short Time Fourier Transform (STFT) to identify and classify different types of interference signals (continuous wave interference at the same frequency, linear frequency modulation interference, pulse interference, etc.). The second layer is anomaly detection based on the Constant False Alarm Rate (CFAR) algorithm, which adaptively sets a detection threshold in the distance spectrum and marks abnormal components exceeding the threshold as interference. The third layer is joint adaptive notch filtering and spectral subtraction interference cancellation, which selectively suppresses the identified interference components.

[0035] The high-precision millimeter-wave radar ranging method based on a multi-dimensional anti-interference mechanism provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0036] like Figure 2 As shown in the embodiment of this application, a high-precision millimeter-wave radar ranging method based on a multi-dimensional anti-interference mechanism is provided. This method may include the following steps 201 to 203: Step 201: Receive the echo signal.

[0037] The echo signal is the signal after the composite modulated transmitted signal is reflected by the target object; the composite modulated transmitted signal is obtained by superimposing a phase-coded sequence on a frequency-modulated continuous wave signal, and the sweep start frequency of the frequency-modulated continuous wave signal can be varied during different sweep cycles.

[0038] For example, the aforementioned frequency-modulated continuous wave signal operates in the millimeter-wave band, such as the 77-81 GHz band. The aforementioned phase coding sequence is a preset maximum length sequence (m-sequence), for example, an m-sequence with a code length of not less than 127. The composite modulated transmission signal is generated by mapping the m-sequence to a phase flip (0° or 180°) and superimposing it onto the frequency-modulated continuous wave signal through a modulator. The aforementioned frequency sweep start frequency is variable during different frequency sweep cycles, meaning that the frequency sweep start frequency of the transmitted signal adaptively changes based on a preset frequency hopping sequence, rather than being fixed at a single frequency point.

[0039] like Figure 3 The diagram shown illustrates the timing relationship of adaptive frequency hopping control provided in this embodiment. A strict synchronization relationship exists between the frequency hopping sequence and the frequency sweep period of the frequency-modulated continuous wave. The specific workflow includes: 1. Spectrum Sensing. At the beginning of each frequency hopping decision cycle (typically consisting of several FMCW sweep cycles), the system uses the receiving channel to perform a rapid spectrum scan of the available bandwidth in the 79 GHz band to assess the interference power level of each sub-band. Spectrum sensing can be achieved through power spectral density (PSD) estimation using a broadband receiver.

[0040] 2. Interference Assessment and Frequency Optimization. Based on the spectrum sensing results, calculate the estimated signal-to-interference-plus-noise ratio (SINR) of the corresponding sub-band for each candidate frequency hopping point. Select the frequency with the optimal SINR as the operating frequency for the next frequency hopping cycle. The selection of candidate frequency points must ensure that the spacing between adjacent frequency points meets the minimum requirement of the FMCW sweep bandwidth.

[0041] 3. Frequency hopping and sweep synchronization. The frequency hopping switching time is strictly aligned with the boundary of the FMCW sweep cycle, ensuring that the transmit frequency changes continuously and linearly within each complete sweep cycle, without phase discontinuity caused by frequency hopping. The frequency hopping control signal drives the reference frequency offset of the PLL frequency synthesizer, causing the sweep start frequency to change during different frequency hopping cycles, while the sweep bandwidth and slope remain constant.

[0042] 4. Frequency hopping sequence management. Pseudo-random frequency hopping sequences are generated by m-sequence or Gold sequence generators. Different radar nodes within the same application scenario use orthogonal or low cross-correlation frequency hopping sequences, fundamentally reducing the probability of co-frequency collisions between multiple radars.

[0043] Specifically, for the generation of the aforementioned composite modulation transmission signal, before step 201, the following steps 200a to 200b may also be included: Step 200a: Dynamically select the working frequency band based on the spectrum sensing results, control the frequency sweep start frequency of the frequency modulated continuous wave transmission signal to switch during the frequency hopping cycle, and synchronize the frequency hopping switching time with the frequency sweep cycle boundary.

[0044] Step 200b: Obtain a preset phase coding sequence, and superimpose the phase coding sequence onto the frequency modulated continuous wave transmitted signal to generate a composite modulated transmitted signal.

[0045] For example, in step 200a above, dynamically selecting the operating frequency band based on the spectrum sensing results may specifically include the following steps 200a1 and 200a2: Step 200a1: During the frequency hopping decision period, use the receiving channel to perform a fast spectrum scan of each sub-band within the working frequency band to obtain the interference level of each sub-band.

[0046] Step 200a2: Based on the interference level of each sub-band, select the frequency point with the optimal signal-to-interference-plus-noise ratio from the preset set of frequency hopping points as the working frequency for the next frequency hopping cycle.

[0047] For example, the aforementioned preset frequency hopping point set includes no fewer than 16 frequency hopping points to ensure sufficient frequency domain diversity gain in complex electromagnetic environments. The phase coding sequence is a maximum length sequence greater than a preset code length, such as an m-sequence with a code length of not less than 127.

[0048] Specifically, step 200b above may also include the following step 200b1: Step 200b1: Map the phase-encoded sequence to a phase flip and superimpose it onto the frequency-modulated continuous wave signal through a modulator to generate a composite modulated transmission signal.

[0049] The chip duration of the phase-coded sequence is less than the beat signal period and greater than the carrier signal period.

[0050] For example, the transmitting end maps the phase-coded sequence to a phase flip and superimposes it onto the frequency-modulated continuous wave (FM continuous wave) signal via a modulator to generate a composite modulated transmitted signal. The chip duration of the phase-coded sequence is shorter than the beat signal period but longer than the carrier signal period; that is, the chip rate is much higher than the beat frequency but much lower than the carrier frequency. This ensures that the coding does not affect the linear frequency modulation (FM) characteristics of the FM continuous wave while providing sufficient coding gain. At the receiving end, the received signal is matched-filtered using the same phase-coded sequence stored locally as the transmitting end. The echo signal from the transmitting radar gains correlation gain due to coding matching and is restored to a pure FM continuous wave beat signal; while other radar signals using different coding sequences are spread and suppressed due to coding mismatch, thereby achieving self-distinguishing between signals at the signal level.

[0051] like Figure 4 The diagram shown is a schematic of phase-coded modulation and demodulation provided in an embodiment of this application. Phase-coded modulation is the second line of defense at the coding domain level, orthogonally superimposed with FMCW modulation to achieve self / other-self differentiation at the signal level.

[0052] Encoding Scheme: A maximum length sequence (m-sequence) with a code length of not less than 127 is selected as the phase code. The transmitted signal maintains a constant phase (0° or 180°) within each chip period. The chip rate is much higher than the FMCW beat frequency but much lower than the carrier frequency, ensuring that the encoding does not affect the linear frequency modulation characteristics of the FMCW while providing sufficient coding gain. Transmitter Processing: The encoder maps the m-sequence to a ±1 phase modulation sequence, which is then superimposed onto the FMCW signal through an I / Q modulator. From a frequency domain perspective, phase encoding broadens the spectrum of the transmitted signal, but this broadening is reversible for the signal itself due to the matching processing at the receiver. Receiver Processing: The received beat IF signal is correlated with a locally stored copy of the phase-coded sequence (matched filtering). The radar's own echo signal gains correlation gain due to coding matching (approximately equal to the dB value of the code length, about 21 dB for a 127-code length), while other radar signals using different codes are spread and suppressed due to coding mismatch. This process is similar to the spread spectrum / despreading mechanism in CDMA communication. Synergy with Phase Ranging: The key innovation lies in the fact that phase encoding demodulation is completed after FMCW beat processing and before phase precision ranging. After encoding and demodulation, the signal is restored to a pure FMCW beat signal, with its phase information fully preserved, without affecting subsequent high-precision phase ranging processing.

[0053] For example, the frequency hopping sequence described above is a pseudo-random sequence, which can be generated by an m-sequence or Gold sequence generator. Different radar nodes within the same application scenario use orthogonal or low cross-correlation frequency hopping sequences, as well as phase-coded sequences with cross-correlation below a preset threshold, to fundamentally reduce the probability of co-frequency collisions and mutual interference between multiple radars.

[0054] Step 202: Mix the echo signal with the transmitted signal to obtain the beat intermediate frequency signal, and use the phase coding sequence to perform matching processing on the beat intermediate frequency signal to identify its own echo signal and interference signal based on coding correlation.

[0055] For example, after the receiving antenna captures the echo signal, it is amplified by a low-noise amplifier and mixed with the transmitted signal to generate a beat intermediate frequency (IF) signal. The aforementioned matching process using phase-coded sequences refers to performing correlation operations (matched filtering) on ​​the beat IF signal using a locally stored phase-coded sequence identical to that of the transmitter. The radar's own echo signal gains correlation gain due to code matching, while other radar signals using different coding sequences or interference signals lacking coding correlation are suppressed due to mismatch. This process is similar to the spread spectrum and despreading mechanisms in code division multiple access (CDMA) communication.

[0056] For example, the matching process described above is performed after mixing and before phase information extraction. After the matching process, the beat signal corresponding to its own radar echo is restored to a pure frequency-modulated continuous wave beat signal, and its phase information is completely preserved, without affecting subsequent phase ranging processing.

[0057] like Figure 5 The diagram shown is a complete flowchart of the multi-dimensional anti-interference processing provided in this application embodiment. The received signal sequentially passes through multiple processing stages, including frequency hopping selection, code-matched filtering, time-frequency domain interference analysis, CFAR detection, and interference cancellation, forming a three-dimensional joint anti-interference system from the frequency domain, coding domain, to the signal processing domain. The adaptive interference detection and suppression algorithm provided in this application embodiment specifically includes: Time-frequency analysis and interference classification: STFT is performed on the beat signal to obtain a two-dimensional time-frequency diagram. Normal target echoes appear as a horizontal straight line (constant beat frequency) on the time-frequency diagram, while different types of interference exhibit different characteristics: co-frequency FMCW interference appears as a diagonal line, pulse interference appears as a vertical broadband stripe, and narrowband interference appears as a horizontal line with a different frequency than the target. Automatic interference classification is performed based on these characteristic templates.

[0058] CFAR Adaptive Detection: Cell-Averaged CFAR (CA-CFAR) or Ordered Statistical CFAR (OS-CFAR) algorithms are used in the range spectrum to adaptively calculate the detection threshold based on the power levels of reference cells surrounding the target cell. Spectral components exceeding the threshold are excluded from the confirmed true target list and are marked as interference components. OS-CFAR exhibits superior threshold stability compared to CA-CFAR in environments with multiple interferences.

[0059] Interference cancellation: Different cancellation strategies are employed for different types of interference. For narrowband interference, an adaptive notch filter is used, with its center frequency and bandwidth dynamically set based on the interference detection results. For broadband pulse interference, time-domain zeroing or interpolation replacement is used. For diffuse interference, spectral subtraction is used, i.e., the interference power spectral density is estimated and subtracted from the mixed spectrum. All cancellation operations are performed in the amplitude domain to preserve the integrity of the target signal's phase information to the greatest extent possible, ensuring that the accuracy of subsequent phase ranging is not affected.

[0060] The above steps constitute the third line of defense at the signal processing domain level, providing the final elimination of interference remaining after frequency hopping and code demodulation. The following section, in conjunction with step 203, discusses... Figure 5 The anti-interference processing procedure shown is explained in detail.

[0061] Step 203: Identify and suppress interference components in the matched signal to obtain a cleaned beat signal, and retain the phase information corresponding to the target object in the cleaned beat signal during the interference suppression process.

[0062] For example, the above-mentioned interference component identification and targeted suppression may specifically include the following steps 203a1 to 203a3: Step 203a1: Perform time-frequency transformation on the matched signal and identify the interference type according to the preset interference time-frequency feature template.

[0063] For example, a short-time Fourier transform is performed on the matched beat signal to obtain a two-dimensional time-frequency diagram. The echo corresponding to a normal target object appears as a horizontal straight line (constant beat frequency) on the time-frequency diagram, while different types of interference exhibit different characteristics: continuous wave interference at the same frequency appears as diagonal stripes, pulse interference appears as vertical broadband stripes, and narrowband interference appears as a horizontal line with a constant frequency different from the target. Based on these preset interference time-frequency feature templates, interference types can be automatically identified and classified.

[0064] Step 203a2: Adaptively set the detection threshold in the distance spectrum using a constant false alarm rate detection algorithm, and mark the spectrum components that exceed the threshold and do not belong to the target object as interference components.

[0065] For example, the above-described constant false alarm rate (CFAR) detection algorithm can employ either the cell-average CFAR algorithm or the ordered statistical CFAR algorithm. The detection threshold is adaptively calculated based on the power level of reference cells surrounding the target cell. Among the spectral components exceeding the threshold, after excluding the spectral components corresponding to the confirmed target object, the remaining components are marked as interference components. In environments with multiple interferences, the ordered statistical CFAR algorithm exhibits superior threshold stability compared to the cell-average CFAR algorithm.

[0066] Step 203a3: Based on the preset mapping relationship between the identified interference type and the suppression strategy, the interference component is targeted to suppress, thereby obtaining the purified beat signal.

[0067] For example, the above-mentioned preset mapping relationship includes: suppressing narrowband interference using an adaptive notch filter, wherein the center frequency and bandwidth of the notch filter are dynamically set by the interference detection results; suppressing broadband pulse interference using time-domain zeroing or interpolation replacement; and suppressing diffuse interference using spectral subtraction, i.e., subtracting the interference power spectral density from the mixed spectrum after estimating the interference power spectral density.

[0068] Specifically, the aforementioned directional suppression is performed in the amplitude domain to preserve the phase information of the purified beat signal corresponding to the target object. This processing method ensures that the phase information of the signal corresponding to the target object is completely preserved during interference suppression, without affecting subsequent phase ranging processing.

[0069] Combination Figure 1 ,like Figure 6The diagram shown illustrates the principle of FMCW and phase-based joint ranging provided in this application embodiment. The joint ranging process includes: performing FFT frequency analysis on the purified beat signal to extract the beat frequency for coarse ranging calculation; extracting phase information at the spectral peaks for fine ranging calculation; and finally combining the coarse and fine distance increments through fuzzy resolution to output a high-precision distance result. Specifically, this joint ranging method includes: FMCW coarse ranging: The standard beat frequency method. The transmitted signal is a continuous wave with a frequency that varies linearly with time, with a sweep bandwidth of B and a sweep period of T. The echo signal is mixed with the transmitted signal to generate a beat signal. The relationship between the beat frequency fb and the target distance R is: fb = 2BR / (cT), where c is the speed of light. fb is extracted by FFT, and the coarse distance R_coarse = fb·c·T / (2B) is calculated. When B = 4GHz, the frequency resolution δf = 1 / T corresponds to a distance resolution of approximately 37.5mm, which can be further improved to the order of approximately 1mm after windowing and interpolation.

[0070] Phase-based fine ranging: After coarse ranging determines the position of the spectral peak of the target echo, the precise phase of that peak is extracted. The phase difference Δ between two adjacent measurements (or two adjacent sweep cycles in a single measurement). The relationship between the distance to the target and the change in distance ΔR is: Δ = 4πΔR / λ, where λ is the carrier wavelength (λ ≈ 3.797 mm at 79 GHz). Therefore, the distance increment is: ΔR = Δ •λ / (4π). The accuracy of phase measurement is limited by the signal-to-noise ratio. Under the condition of SNR ≥ 30dB, the standard deviation of phase estimation can reach about 0.01 radians, which corresponds to a distance accuracy of about 0.6μm, leaving a margin to meet the 0.02mm accuracy requirement.

[0071] Ambiguity Removal: The ambiguity-free range of pure phase ranging is only λ / 2 ≈ 1.9mm, meaning that when the distance change exceeds 1.9mm, the phase will undergo 2π wraparound, causing ambiguity. The millimeter-level accuracy provided by FMCW coarse ranging is sufficient to lock the true distance within one ambiguity-free phase cycle, thus completely eliminating ambiguity. The final result of joint ranging is: R = R_coarse + ΔR_phase, where R_coarse provides the absolute distance reference, and ΔR_phase provides sub-millimeter accuracy correction. The following section, in conjunction with step 204, further details... Figure 6 The combined ranging procedure shown is explained in detail.

[0072] Step 204: Obtain the coarse distance to the target object based on the frequency information of the purified beat signal, and obtain the fine distance increment based on the phase information corresponding to the target object. Combine the coarse distance and the fine distance increment to obtain the distance information of the target object.

[0073] For example, step 204 above may specifically include steps 204a1 to 204a3: Step 204a1: Perform frequency analysis on the purification beat signal, and obtain the coarse measurement distance based on the linear relationship between beat frequency and distance.

[0074] For example, a windowed Fourier transform is performed on the purified beat signal to obtain the distance spectrum, and the spectral peak corresponding to the target object is located. Based on the beat frequency corresponding to this spectral peak, a coarse distance measurement with millimeter-level accuracy is calculated using the linear relationship between the beat frequency and the distance.

[0075] Step 204a2: Extract the phase information at the spectral peak corresponding to the target object in the purification beat signal, and obtain the precision distance increment based on the relationship between the phase difference and distance change between adjacent measurements or adjacent sweep cycles.

[0076] For example, after coarse ranging determines the position of the spectral peak corresponding to the target object, the precise phase value at that peak is extracted. A correlation exists between the phase difference between two adjacent measurements or two adjacent frequency sweep cycles and the change in target distance, thereby calculating the precise distance increment with sub-millimeter accuracy. For example, when the signal-to-noise ratio meets preset conditions (e.g., signal-to-noise ratio not less than 30dB), the standard deviation of phase estimation can reach approximately 0.01 radians, and the corresponding distance accuracy can meet the requirements of sub-millimeter ranging.

[0077] Step 204a3: Determine the phase ambiguity period of the fine distance increment based on the coarse distance measurement, and add the coarse distance measurement and the fine distance increment to obtain the distance information of the target object.

[0078] For example, due to the limitation of the unambiguous range in pure phase ranging, when the distance change exceeds half a carrier wavelength, the phase will periodically wrap around, causing ambiguity. The millimeter-level accuracy provided by the coarse distance measurement is sufficient to lock the true distance within one unambiguous phase period, thereby completely eliminating ambiguity. The correct ambiguity period of the fine distance increment is determined based on the coarse distance measurement, and the two are added together to obtain the final high-precision distance information, where the coarse distance measurement provides an absolute distance reference, and the fine distance increment provides sub-millimeter accuracy correction.

[0079] Experiments have demonstrated that, under different signal-to-interference ratio (SIR) conditions, the method provided in this application has a significant advantage in ranging accuracy compared to traditional FMCW radar schemes and single anti-jamming schemes. As the SIR decreases (interference intensity increases), the ranging accuracy of traditional schemes deteriorates sharply. However, the method provided in this application, due to its three-dimensional joint anti-jamming system of frequency hopping, phase coding, and adaptive interference suppression, maintains stable high-precision ranging performance even at low SIRs, achieving an interference suppression ratio of over 40dB.

[0080] The high-precision millimeter-wave radar ranging method based on a multi-dimensional anti-interference mechanism provided in this application constructs a three-dimensional joint anti-interference system of "frequency domain-coding domain-signal processing domain". Based on frequency hopping control and phase coding modulation, it utilizes matching processing to separate its own echo from interference signals. Then, it eliminates interference through three levels: joint time-frequency domain interference feature identification, constant false alarm rate adaptive detection, and directional suppression. Furthermore, during interference suppression, processing in the amplitude domain is performed to completely preserve the phase information corresponding to the target object. Finally, high-precision ranging is achieved through a joint architecture of coarse and fine ranging. This method resolves the coupling contradiction between anti-interference processing and high-precision phase ranging, maintaining stable high-precision ranging performance even in complex electromagnetic interference environments. It can be widely applied in industrial precision measurement and micro-vibration detection scenarios.

[0081] The high-precision millimeter-wave radar ranging method based on a multi-dimensional anti-interference mechanism provided in this application first receives an echo signal; the echo signal is the signal reflected by a composite modulated transmitted signal after being transmitted through a target object; the composite modulated transmitted signal is obtained by superimposing a phase-coded sequence on a frequency-modulated continuous wave signal, and the sweep start frequency of the frequency-modulated continuous wave signal is variable during different sweep cycles; then, the echo signal is mixed with the transmitted signal to obtain a beat intermediate frequency signal, and the beat intermediate frequency signal is matched using the phase-coded sequence to identify its own echo signal and interference signals based on the coding correlation; interference components are identified and directionally suppressed on the matched signal to obtain a cleaned beat signal, and the phase information corresponding to the target object in the cleaned beat signal is retained during the interference suppression process; finally, a coarse distance to the target object is obtained based on the frequency information of the cleaned beat signal, and a fine distance increment is obtained based on the phase information corresponding to the target object; combining the coarse distance and the fine distance increment, the distance information of the target object is obtained. Thus, by constructing an anti-interference system that coordinates the frequency domain, coding domain, and signal processing domain, the target echo phase information is fully preserved while effectively suppressing various types of interference. This solves the coupling contradiction between anti-interference processing and high-precision phase ranging in complex electromagnetic environments, and achieves high-precision ranging.

[0082] Figure 7An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 7 As shown, the electronic device may include: a processor 710, a communications interface 720, a memory 730, and a communications bus 740, wherein the processor 710, the communications interface 720, and the memory 730 communicate with each other through the communications bus 740. The processor 710 can call logic instructions in the memory 730 to execute a high-precision millimeter-wave radar ranging method based on a multi-dimensional anti-interference mechanism. This method includes: first, receiving an echo signal; the echo signal is a signal reflected from a target object after a composite modulated transmitted signal; the composite modulated transmitted signal is obtained by superimposing a phase-coded sequence onto a frequency-modulated continuous wave signal, and the sweep start frequency of the frequency-modulated continuous wave signal is variable during different sweep cycles; then, mixing the echo signal with the transmitted signal to obtain a beat intermediate frequency signal, and using the phase-coded sequence to perform matching processing on the beat intermediate frequency signal to identify its own echo signal and interference signals based on coding correlation; performing interference component identification and directional suppression on the matched signal to obtain a purified beat signal, and retaining the phase information corresponding to the target object in the purified beat signal during interference suppression; finally, obtaining a coarse distance to the target object based on the frequency information of the purified beat signal, and obtaining a fine distance increment based on the phase information corresponding to the target object, and combining the coarse distance and the fine distance increment to obtain the distance information of the target object. Thus, by constructing an anti-interference system that coordinates the frequency domain, coding domain, and signal processing domain, the target echo phase information is fully preserved while effectively suppressing various types of interference. This solves the coupling contradiction between anti-interference processing and high-precision phase ranging in complex electromagnetic environments, and achieves high-precision ranging.

[0083] Furthermore, the logical instructions in the aforementioned memory 730 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0084] On the other hand, this application also provides a computer program product, which includes a computer program stored on a computer-readable storage medium. The computer program includes program instructions, and when the program instructions are executed by a computer, the computer can execute the high-precision millimeter-wave radar ranging method based on the multi-dimensional anti-interference mechanism provided by the above methods. The method includes: first, receiving an echo signal; the echo signal is a signal after a composite modulated transmitted signal is reflected by a target object; the composite modulated transmitted signal is obtained by superimposing a phase-coded sequence on a frequency-modulated continuous wave signal, and the sweep start frequency of the frequency-modulated continuous wave signal is variable during different sweep cycles; then, receiving the echo signal... The wave signal and the transmitted signal are mixed to obtain a beat intermediate frequency (IF) signal. The phase coding sequence is then used to match this beat IF signal to identify its own echo signal and interference signals based on coding correlation. Interference components are identified and directionally suppressed in the matched signal to obtain a cleaned beat signal. During interference suppression, the phase information corresponding to the target object in the cleaned beat signal is preserved. Finally, a coarse distance to the target object is obtained based on the frequency information of the cleaned beat signal, and a fine distance increment is obtained based on the phase information corresponding to the target object. Combining the coarse distance and the fine distance increment yields the distance information of the target object. Thus, by constructing a coordinated anti-interference system across the frequency domain, coding domain, and signal processing domain, multiple types of interference are effectively suppressed while the target echo phase information is fully preserved. This resolves the coupling contradiction between anti-interference processing and high-precision phase ranging in complex electromagnetic environments, achieving high-precision ranging.

[0085] Furthermore, this application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the high-precision millimeter-wave radar ranging methods based on multi-dimensional anti-interference mechanisms provided above. The method includes: first, receiving an echo signal; the echo signal is a signal obtained after a composite modulated transmitted signal is reflected by a target object; the composite modulated transmitted signal is obtained by superimposing a phase-coded sequence onto a frequency-modulated continuous wave signal, and the sweep start frequency of the frequency-modulated continuous wave signal is variable during different sweep cycles; then, mixing the echo signal with the transmitted signal to obtain a beat intermediate frequency signal. The system uses the phase coding sequence to match the beat intermediate frequency signal, identifying its own echo signal and interference signals based on coding correlation. Interference components are identified and targeted to suppress the matched signal, resulting in a cleaned beat signal. During interference suppression, the phase information corresponding to the target object in the cleaned beat signal is preserved. Finally, a coarse distance to the target object is obtained based on the frequency information of the cleaned beat signal, and a fine distance increment is obtained based on the phase information corresponding to the target object. Combining the coarse distance and the fine distance increment, the distance information of the target object is obtained. Thus, by constructing a coordinated anti-interference system across the frequency domain, coding domain, and signal processing domain, the system effectively suppresses various types of interference while fully preserving the target echo phase information, resolving the coupling contradiction between anti-interference processing and high-precision phase ranging in complex electromagnetic environments, and achieving high-precision ranging.

[0086] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0087] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A high-precision millimeter-wave radar ranging method based on a multi-dimensional anti-interference mechanism, characterized in that, include: Receive echo signal; the echo signal is the signal after the composite modulated transmitted signal is reflected by the target object; the composite modulated transmitted signal is obtained by superimposing a phase-coded sequence on a frequency-modulated continuous wave signal, and the sweep start frequency of the frequency-modulated continuous wave signal can be varied during different sweep cycles; The echo signal is mixed with the transmitted signal to obtain the beat intermediate frequency signal, and the beat intermediate frequency signal is matched using the phase coding sequence to identify its own echo signal and interference signal based on coding correlation. Interference components are identified and targeted suppression is performed on the matched signal to obtain the cleaned beat signal, and the phase information corresponding to the target object in the cleaned beat signal is retained during the interference suppression process; The coarse distance to the target object is obtained based on the frequency information of the purified beat signal, and the fine distance increment is obtained based on the phase information corresponding to the target object. The distance information of the target object is obtained by combining the coarse distance and the fine distance increment.

2. The method according to claim 1, characterized in that, The composite modulated transmission signal is generated in the following manner: The operating frequency band is dynamically selected based on the spectrum sensing results, and the frequency sweep start frequency of the frequency-modulated continuous wave transmission signal is switched during the frequency hopping cycle, with the frequency hopping switching time synchronized with the boundary of the frequency sweep cycle. A preset phase coding sequence is obtained, and the phase coding sequence is superimposed on the frequency modulated continuous wave transmitted signal to generate a composite modulated transmitted signal.

3. The method according to claim 2, characterized in that, The dynamic selection of the operating frequency band based on the spectrum sensing results includes: During the frequency hopping decision cycle, the interference level of each sub-band in the working frequency band is obtained; Based on the interference level of each sub-band, the frequency point with the optimal signal-to-interference-plus-noise ratio is selected from the preset set of frequency hopping points as the operating frequency for the next frequency hopping cycle.

4. The method according to claim 1 or 2, characterized in that, The phase-coded sequence is a maximum length sequence greater than a preset code length; the step of superimposing the phase-coded sequence on the frequency-modulated continuous wave transmitted signal to generate a composite modulated transmitted signal includes: The phase-encoded sequence is mapped to a phase flip and superimposed onto the frequency-modulated continuous wave signal through a modulator to generate a composite modulated transmission signal. The chip duration of the phase-coded sequence is less than the beat signal period and greater than the carrier signal period.

5. The method according to claim 1 or 2, characterized in that, The process of identifying and suppressing interference components in the matched signal to obtain a cleaned beat signal includes: The matched signal is subjected to time-frequency transformation, and the interference type is identified according to the preset interference time-frequency feature template; In the distance spectrum, a constant false alarm rate detection algorithm is used to adaptively set the detection threshold, and the spectrum components that exceed the threshold and do not belong to the target object are marked as interference components. Based on the preset mapping relationship between the identified interference type and the suppression strategy, the interference component is targeted to suppress, thereby obtaining the purified beat signal.

6. The method according to claim 5, characterized in that, The interference time-frequency feature template includes at least: the oblique stripe feature corresponding to continuous wave interference at the same frequency, the vertical broadband stripe feature corresponding to pulse interference, and the constant frequency feature corresponding to narrowband interference; the preset mapping relationship includes: notch filtering for narrowband interference, time-domain zeroing or interpolation replacement for broadband pulse interference, and spectral subtraction for diffuse interference.

7. The method according to claim 5, characterized in that, The directional suppression is performed in the amplitude domain to preserve the phase information in the cleaned beat signal corresponding to the target object.

8. The method according to claim 1 or 2, characterized in that, The step of obtaining a coarse distance to the target object based on the frequency information of the purification beat signal, and obtaining a fine distance increment based on the phase information corresponding to the target object, includes: Frequency analysis is performed on the purification beat signal, and the coarse distance is obtained based on the linear relationship between the beat frequency and the distance. The phase information at the spectral peak corresponding to the target object in the purification beat signal is extracted, and the precision distance increment is obtained based on the relationship between the phase difference and distance change between adjacent measurements or adjacent sweep cycles.

9. The method according to claim 8, characterized in that, The step of combining the coarse distance measurement increment with the fine distance measurement increment to obtain the distance information of the target object includes: The phase ambiguity period of the fine distance increment is determined based on the coarse distance measurement, and the distance information of the target object is obtained by adding the coarse distance measurement and the fine distance increment.

10. A high-precision millimeter-wave radar ranging system based on a multi-dimensional anti-interference mechanism, characterized in that, The system includes a module for executing the high-precision millimeter-wave radar ranging method based on a multi-dimensional anti-interference mechanism as described in any one of claims 1 to 9.

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