A wind field detection method based on adjustable pulse waveform generation from meteorological millimeter-wave radar

Abstract

This invention discloses a wind field detection method based on adjustable pulse waveform generation from meteorological millimeter-wave radar, comprising constructing a first transmitted waveform for near-ground low-altitude detection and a second transmitted waveform for mid-to-high-altitude detection, and loading different pulse waveforms respectively. m Sequence encoding forms a coded modulation waveform; within the same detection period, two types of coded waveforms are transmitted in a time-division manner based on a preset control strategy; target echo signals are received, and matched filtering is performed using the corresponding coded sequences to separate the waveform echoes; the separated echo data undergoes range grouping and Doppler processing to obtain radial velocity information at different altitudes; and the near-surface and mid-to-high-altitude detection results are fused based on the range distribution to generate a continuous vertical wind field profile. This invention improves the separability and anti-interference capability of echoes at different altitudes by combining time-domain scheduling with coding-domain differentiation, achieving coordinated unification of near-surface fine detection and mid-to-high-altitude long-range detection.

Description

Technical Field

[0001] This invention belongs to the field of wind field detection technology, specifically relating to a wind field detection method based on adjustable pulse waveform generation from meteorological millimeter-wave radar. Background Technology

[0002] 24GHz millimeter-wave radar has significant application value in the field of meteorological wind field detection, and can be used for non-contact measurement of meteorological elements such as atmospheric wind field, turbulence, and wind shear. Meteorological radar typically detects the Doppler frequency shift in the echo signals from scatterers such as aerosols and cloud droplets in the atmosphere to retrieve wind speed information. Its detection performance directly affects the accuracy and reliability of wind field observation results.

[0003] In existing technologies, 24GHz meteorological millimeter-wave radar transmitters typically employ a pulse system with fixed parameters, such as fixed pulse width and fixed pulse repetition frequency. This type of fixed waveform system has the following drawbacks: 1. In near-ground low-altitude wind field detection scenarios, there is an inherent contradiction between range resolution and transmit power. According to the principle of radar range resolution, range resolution is positively correlated with pulse width. To improve range resolution, a narrower pulse is usually required. However, a narrower pulse will reduce the single-pulse energy and average transmit power, thus affecting the signal detection performance under weak scattering echo conditions.

[0004] 2. Under long-range detection conditions, there is a mutually restrictive relationship between the maximum unambiguous distance and the maximum unambiguous velocity. The maximum unambiguous distance is related to the pulse repetition period, while the maximum unambiguous velocity is related to the pulse repetition frequency. When the detection distance is increased by adjusting the pulse repetition frequency, the maximum unambiguous velocity is easily reduced, thus affecting the measurement capability under conditions of high wind speed; conversely, increasing the pulse repetition frequency to increase the velocity measurement range will reduce the maximum unambiguous distance.

[0005] 3. Atmospheric wind fields at different altitudes inherently differ. The wind field in the low-altitude near-surface region varies drastically, requiring high time and distance resolution; while the wind field in the mid-to-high altitude region is relatively stable, but demands greater long-range coverage. Under fixed waveform parameters, it is difficult to simultaneously meet the differentiated detection performance requirements of different altitudes.

[0006] Furthermore, existing fixed waveform designs lack flexible parameter adjustment capabilities. When using a single fixed pulse parameter, the system struggles to optimize its detection performance according to changes in different meteorological environments, thus limiting its adaptability to complex weather conditions to some extent.

[0007] To address the aforementioned issues, prior art CN120686196A discloses a multi-mode wind profiler radar detection system and method. The multi-mode wind profiler radar detection system includes: a mode control module for storing low-mode, medium-mode, and high-mode detection parameters in a parameter library, executing mode switching logic, and generating control signals for pulse width and repetition period; a transmit / receive module for transmitting corresponding pulse signals according to the mode detection parameters and receiving echoes for A / D conversion via high-speed acquisition; and a data fusion module for time synchronization and overlapping area weighted fusion of the multi-mode detection data to generate continuous wind profiler data. This scheme employs two different transmit waveforms with varying parameters, using a time-division multiplexing approach for detection tasks at different altitudes. For example, a narrow-pulse, high-repetition-frequency waveform is used for low-altitude detection, and a wide-pulse, low-repetition-frequency waveform is used for medium- and high-altitude detection.

[0008] This method can distinguish between different detection tasks to a certain extent, but the distinction between different tasks mainly depends on the time scheduling method and parameter differences. When the detection environment is complex or the echo signal is weak, the separability between the echoes of different tasks may still be limited.

[0009] Therefore, under the existing dual-waveform time-division system, although it can achieve detection coverage at different altitudes to a certain extent, there is still room for improvement in terms of signal differentiation capability for different detection tasks, detection capability under weak echo conditions, and system adaptability to complex environments. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a wind field detection method based on adjustable pulse waveform generation from meteorological millimeter-wave radar.

[0011] The objective of this invention can be achieved through the following technical solutions: This invention provides a wind field detection method based on adjustable pulse waveform generation from meteorological millimeter-wave radar, comprising the following steps: Step S1: Construct the first and second transmission waveforms; Step S2: Load the first encoding sequence onto the first transmitted waveform and load the second encoding sequence onto the second transmitted waveform; Step S3: Based on the preset transmission control strategy, schedule the transmission of the first and second transmission waveforms after loading and encoding, so that the two types of transmission waveforms are transmitted in segments according to the set time relationship, and complete near-ground low-altitude detection and medium-high-altitude detection within the same detection cycle; Step S4: Receive the target echo signal, and perform matched filtering on the target echo signal based on the first coding sequence and the second coding sequence respectively to separate and obtain the first echo data corresponding to the first transmitted waveform and the second echo data corresponding to the second transmitted waveform; Step S5: Perform Doppler processing on the first echo data and the second echo data respectively to obtain the corresponding radial velocity, and obtain the near-ground low-altitude detection results and the mid-to-high-altitude detection results; Step S6: Based on the distance distribution, the near-ground low-altitude detection results and the mid-to-high-altitude detection results are fused to generate the final wind field detection results.

[0012] Furthermore, the first transmitted waveform is used for near-ground low-altitude detection, and the second transmitted waveform is used for medium- and high-altitude detection. The pulse width of the first transmitted waveform is smaller than the pulse width of the second transmitted waveform, and the repetition frequency of the first transmitted waveform is higher than the repetition frequency of the second transmitted waveform.

[0013] Furthermore, the step of loading a first coding sequence onto the first transmitted waveform and a second coding sequence onto the second transmitted waveform specifically includes: A first encoding sequence and a second encoding sequence are generated based on preset rules. Both the first encoding sequence and the second encoding sequence are pseudo-random sequences and correspond to different... sequence; The first encoded sequence is used as the first control sequence to act on the first transmitted waveform, and the pulse state of the first transmitted waveform is serialized and modulated to form the first transmitted waveform after encoding and modulation. The second coded sequence is used as the second control sequence to act on the second transmitted waveform, and the pulse state of the second transmitted waveform is serialized and modulated to form the coded and modulated second transmitted waveform; Among them, the The sequence is generated by a shift register, and its length satisfies ,in For shift register stages, The length of the encoded sequence.

[0014] Furthermore, the first encoding sequence differs from the second encoding sequence in either the generator polynomial or the initial state; The first encoded sequence and the second encoded sequence satisfy a low cross-correlation characteristic, and the corresponding cross-correlation function is expressed as: in, and These represent the first encoded sequence and the second encoded sequence, respectively. Indicates the delay amount. Represents a sequence index. Indicates that the first encoded sequence is in the... The value at each position Indicates that the second encoded sequence is in the first... The value at each position This indicates that the delay is The cross-correlation function value between the first encoded sequence and the second encoded sequence at that time; The absolute value of the cross-correlation function between the first encoded sequence and the second encoded sequence is less than a preset threshold.

[0015] Furthermore, step S3 specifically includes: A complete detection cycle is divided into at least two time periods, including a first time period and a second time period; During the first time period, the first transmitted waveform, which is encoded and modulated by the first coding sequence, is continuously transmitted. During the second time period, the second transmission waveform, encoded and modulated by the second coding sequence, is continuously transmitted; The first time period and the second time period are arranged in a preset order, and the duration of the first time period and the duration of the second time period are configured according to the detection requirements.

[0016] Furthermore, the step of performing matched filtering on the target echo signal based on the first encoding sequence and the second encoding sequence respectively, to separate and obtain the first echo data corresponding to the first transmitted waveform and the second echo data corresponding to the second transmitted waveform, specifically includes: The received target echo signal is represented as a discrete signal. ; A first matched filter is constructed based on the first encoded sequence, and a first correlation operation is performed on the target echo signal to obtain a first processed output, the formula of which is: A second matched filter is constructed based on the second encoded sequence, and a second correlation operation is performed on the target echo signal to obtain a second processed output, as shown in the formula: in, This represents the first encoded sequence. This represents the second encoded sequence. Indicates a lazy index. This represents the first processing output corresponding to the first encoded sequence. This represents the second processing output corresponding to the second encoded sequence; Data is extracted from the first processing output and the second processing output to obtain the first echo data and the second echo data.

[0017] Furthermore, the step of performing Doppler processing on the first echo data and the second echo data respectively to obtain the corresponding radial velocity, and thus obtaining the near-ground low-altitude detection results and the mid-to-high-altitude detection results, specifically includes: The first echo data and the second echo data are respectively processed by range cell grouping to form an echo sequence arranged by range gate; Phase change analysis is performed on the echo data in the slow time dimension within each range cell, and the phase change sequence is processed by spectral transformation to obtain the corresponding Doppler spectrum. The radial velocity is determined based on the Doppler frequency corresponding to the spectral peak in the Doppler spectrum. The radial velocity corresponding to the first echo data is taken as the near-ground low-altitude detection result, and the radial velocity corresponding to the second echo data is taken as the mid-to-high-altitude detection result.

[0018] Furthermore, the radial velocity With Doppler frequency The relationship between them is satisfied: in, For radar operating wavelength, This represents the Doppler frequency within the corresponding range cell.

[0019] Furthermore, the step of performing range cell grouping processing on the first echo data and the second echo data respectively to form an echo sequence arranged by range gates specifically includes: The first echo data and the second echo data are resampled according to a preset sampling interval to obtain a discrete echo sampling sequence; Based on the round-trip time delay relationship of radar signal propagation, the sampling index is converted into the corresponding range cell, where the first... The distances corresponding to each distance unit satisfy the following: in, Indicates the first The detection range corresponding to each distance unit At the speed of light, This indicates the round-trip propagation delay for the corresponding sampling point; The first echo data and the second echo data are divided according to the distance unit, so that echo data belonging to the same distance range are grouped into the same distance gate; The echo data within each distance gate are arranged in chronological order to form the corresponding distance gate echo sequence.

[0020] Furthermore, the fusion processing of the near-surface low-altitude detection results and the mid-to-high-altitude detection results based on distance distribution to generate the final wind field detection results specifically includes: Based on the distance gate division results, all distance units are sorted from near to far according to the detection distance, and the distance units are divided into three continuous intervals according to the preset distance gate division rules, including the near distance interval, the middle distance interval and the far distance interval. Wherein, the near-range interval corresponds to the range gate range of the first transmitted waveform, the far-range interval corresponds to the range gate range of the second transmitted waveform, and the intermediate range is the range gate range of the overlap between the first transmitted waveform and the second transmitted waveform; Within the short-range interval, the radial velocity corresponding to the first echo data is used as the output wind field result; Within the long-distance range, the radial velocity corresponding to the second echo data is used as the output wind field result; Within the intermediate distance range, the radial velocities corresponding to the first echo data and the second echo data are weighted and fused to obtain the fused radial velocity. The weighted fusion process is calculated using the following formula: in, This represents the radial velocity corresponding to the first echo data. This indicates the radial velocity corresponding to the second echo data. These are weighting coefficients related to the location of the distance cell; Indicates the fusion radial velocity; The output results of each distance interval are combined to form a complete vertical wind field profile.

[0021] Compared with the prior art, the present invention has the following advantages: (1) In the prior art, meteorological millimeter-wave radar usually adopts a single waveform design with a fixed pulse width and a fixed pulse repetition frequency. In the detection of near-surface low-altitude wind fields, narrow pulses are often used to improve range resolution. However, this method will reduce the average transmission power, resulting in a low signal-to-noise ratio under weak scattering conditions, which affects the stable observation of fine structures such as low-altitude wind shear and turbulence. This invention constructs a first transmission waveform and adopts a narrow pulse high repetition frequency design. At the same time, it combines the first coding sequence to perform serialization modulation and enhances the echo extraction capability at the receiving end through matched filtering and correlation decoding. This allows the low-altitude echo to obtain coding processing gain while maintaining high range resolution, thereby improving the resolution and stability of near-surface wind field detection and effectively improving the measurement reliability under weak echo conditions.

[0022] (2) In the prior art, a wide pulse low repetition frequency design is usually adopted to improve the detection range of mid-to-high altitude wind fields. However, this method will lead to a decrease in range resolution and is prone to insufficient detection capability under weak echo conditions at long distances. The present invention constructs a second transmission waveform and adopts a wide pulse low repetition frequency design, while superimposing a second coding sequence for modulation. On the basis of ensuring long-distance detection capability, coding processing gain is introduced, and the weak echo energy gathering effect is enhanced by coding correlation demodulation, thereby effectively improving the detection capability of mid-to-high altitude wind field echoes and realizing stable coverage and reliable detection of mid-to-high altitude tropospheric wind fields.

[0023] (3) In the prior art, the design of fixed pulse repetition frequency creates an inherent contradiction between the maximum unambiguous distance and the maximum unambiguous velocity, making it difficult to simultaneously meet the requirements of long-distance coverage and high wind speed measurement. This invention sets up a first transmission waveform and a second transmission waveform, and configures different pulse widths and repetition frequencies respectively, so that the two types of waveforms can perform tasks in the time dimension. This enables the separate configuration of different observation ranges and different velocity resolution requirements at the system level, effectively alleviating the mutual constraint between distance coverage capability and velocity measurement capability, and improving the overall wind field detection adaptation range.

[0024] (4) In the prior art, a single waveform or time-division switching method is usually used to distinguish between low-altitude and high-altitude detection missions. In complex meteorological environments or under weak echo conditions, echoes from different missions are prone to aliasing in the time domain, resulting in mutual interference between wind field information at different altitudes. This invention introduces different m-sequence codes into the first and second transmitted waveforms respectively, and uses matched filtering correlation decoding at the receiving end to separate the signals. This makes different detection missions distinguishable not only in the time domain, but also separable in the coding domain, thereby significantly improving the separability of echoes at different altitudes, reducing crosstalk between missions, and improving the clarity and reliability of the overall detection results.

[0025] (5) In the prior art, radar systems are usually difficult to dynamically optimize their configuration according to the wind field variation characteristics at different altitudes, resulting in insufficient adaptability of the system when facing complex meteorological conditions such as severe convective weather, typhoon processes, or rapid changes in the boundary layer. This invention uses FPGA to realize the timing scheduling control of the first and second transmitted waveforms, and supports the loading of coding sequences and dynamic adjustment of parameters, enabling the system to flexibly configure the waveform ratio, transmission order, and coding structure according to observation requirements, thereby improving the adaptive detection capability for different meteorological scenarios and enhancing the system's operational flexibility and environmental adaptability.

[0026] (6) In the prior art, traditional dual-waveform schemes usually rely on complex hardware structures or multiple transmission links to achieve different detection modes, resulting in high system complexity, high cost, and difficulty in engineering deployment. Based on the existing millimeter-wave radar hardware architecture, this invention achieves multi-mode detection capability by software and digital transformation of the waveform parameter layer and coding modulation layer. It only requires the introduction of encoding loading and related decoding processing, thereby significantly reducing the system transformation cost and improving the feasibility of engineering implementation and the value of promotion and application. Attached Figure Description

[0027] Figure 1 This is a flowchart of the wind field detection method according to an embodiment of the present invention; Figure 2 This is a flowchart illustrating the radial velocity calculation process according to an embodiment of the present invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0029] This embodiment provides a wind field detection method based on adjustable pulse waveform generation from meteorological millimeter-wave radar, such as... Figure 1 As shown, it includes the following steps: Step S1: Construct the first and second transmission waveforms; In one implementation, two types of transmission waveforms for wind field detection are first constructed, including a first transmission waveform and a second transmission waveform, which are respectively designed for atmospheric wind field detection needs at different altitudes.

[0030] The first transmitted waveform is used for near-surface low-altitude wind field detection. This region typically exhibits wind shear, turbulence, and uneven local aerosol distribution. The echo signals are characterized by rapid temporal changes and fine spatial structures, thus requiring high range and temporal resolution. Based on this characteristic, the first transmitted waveform uses a shorter pulse duration, reducing the area occupied by the transmitted signal on the time axis and thereby improving range resolution. The basic relationship satisfies the correspondence between radar range resolution and pulse width; that is, range resolution is directly proportional to pulse width. A smaller pulse width allows for finer spatial range unit differentiation, which is beneficial for resolving subtle structural changes in the near-surface wind field. Simultaneously, the first transmitted waveform uses a higher pulse repetition frequency, increasing the number of transmitted pulses per unit time, thereby increasing the slow-time sampling density. This enhances the stability of Doppler frequency estimation and improves the time tracking capability for rapidly changing wind fields. A high repetition frequency also improves the equivalent distribution of average transmitted power in the time dimension, making low-altitude echoes under weak scattering conditions easier to detect stably.

[0031] The second transmitted waveform is used for mid-to-high-altitude wind field detection. The mid-to-high-altitude region typically corresponds to the upper troposphere, where the wind field structure is relatively stable, but the detection distance is longer, and the echo signal attenuation is more significant, requiring higher energy accumulation capabilities and maximum detection distance. Based on this characteristic, the second transmitted waveform uses a longer pulse duration. By increasing the energy accumulation time of a single pulse, the energy output level of a single transmission is improved, thereby enhancing the detectability of long-distance echoes. While a longer pulse reduces range resolution to some extent, the wind field in this region changes relatively slowly; this trade-off allows for continuous observation of mid-to-high-altitude wind fields while maintaining the detection distance. Simultaneously, the second transmitted waveform uses a lower pulse repetition frequency to increase the pulse repetition period, thereby increasing the maximum unambiguous distance. This ensures that long-distance echoes can be stably received and processed without range ambiguity and reduces the probability of aliasing in the temporal dimension of high-altitude echoes.

[0032] By differentiating the two types of transmitted waveforms, low-altitude and mid-to-high-altitude detection missions achieve a complementary relationship in terms of both time and energy scales: the first transmitted waveform emphasizes high resolution and high dynamic response capabilities to capture complex wind field structures near the ground; the second transmitted waveform emphasizes high energy and long-range coverage capabilities to ensure stable observation of mid-to-high-altitude wind fields. This approach, based on the joint configuration of pulse width and repetition frequency, allows the same radar system to achieve layered optimization of wind field detection performance at different altitudes without changing the hardware structure, thereby improving overall detection adaptability and observation coverage.

[0033] Step S2: Load the first encoding sequence for the first transmitted waveform and the second encoding sequence for the second transmitted waveform; In one embodiment, coding modulation processing is introduced for the first transmitted waveform and the second transmitted waveform respectively, so that the two types of echoes can not only be distinguished at the receiving end according to the transmission timing, but also the separability can be further enhanced through coding features, thereby improving the anti-interference capability and weak echo detection capability under complex weather conditions.

[0034] When loading the first encoding sequence for the first transmitted waveform and the second encoding sequence for the second transmitted waveform, two sets of encoding sequences are first generated based on the principle of pseudo-random sequence construction. Sequences serve as the basic coding structure. The sequence is generated through a shift register feedback structure, and its sequence length satisfies ,in For shift register stages, This is the length of the encoded sequence. The reason for using this structure is that... The sequence has statistical characteristics close to white noise and good autocorrelation peak characteristics. It can form obvious correlation peaks in radar echo processing, which facilitates the accurate positioning of target range cells. At the same time, its generation structure is simple and suitable for real-time implementation in FPGA or dedicated digital signal processing hardware.

[0035] Two groups were generated. During sequence generation, the first and second coded sequences are kept different in either the generator polynomial or the initial state. Different generator polynomials determine different feedback path structures, while different initial states determine different sequence start phases. Both methods ensure the independence of the two sets of sequences in terms of time-domain statistical characteristics, thereby avoiding significant aliasing peaks during correlation processing at the receiver and improving the distinguishability between different detection tasks.

[0036] When the first coded sequence is applied as the first control sequence to the first transmitted waveform, and the second coded sequence is applied as the second control sequence to the second transmitted waveform, pulse-by-pulse modulation is performed on the on / off state or equivalent amplitude state of the transmitted pulses, converting the original continuous pulse sequence into a discrete pulse sequence with a coded structure. This processing essentially redistributes the transmitted energy in the time dimension, transforming the transmitted signal from a single-periodic structure into a coded signal with an information extension dimension. Therefore, at the receiving end, matched filtering can be used to improve the processing gain.

[0037] To describe the correlation between two sets of coded sequences, a cross-correlation function expression is introduced: in, and These represent the first and second encoded sequences, respectively. Indicates the delay amount. Represents a sequence index. Indicates the first encoded sequence in the th order. The value at each position Indicates the second encoded sequence in the th order. The value at each position This indicates that the delay is The cross-correlation function value between the first and second encoded sequences; The purpose of setting this cross-correlation function is to quantify the degree of interference coupling between the two sets of codes. Since the radar receiver needs to recover the two types of echo signals through correlation filtering, if the correlation between the two sets of codes is too high, it will cause sidelobe elevation or spurious peak interference in the matched filter output, thus affecting the target separation accuracy. Therefore, during the coding design stage, the amplitude of the cross-correlation function between the first and second coding sequences is controlled so that its absolute value is less than a preset threshold. This threshold is used to constrain the maximum acceptable level of cross-interference, thereby ensuring that the two types of echoes can form a clear main peak response during the correlation decoding process.

[0038] Through the above-mentioned coding loading and cross-correlation constraint design, the first and second transmitted waveforms not only have physical layer differences in pulse width and repetition frequency, but also have statistical independence in the coding domain. This improves the system's ability to separate and stably detect low-altitude wind fields from mid- and high-altitude wind fields in the context of complex meteorological echoes.

[0039] Step S3: Based on the preset transmission control strategy, schedule the transmission of the first and second transmission waveforms after loading and encoding, so that the two types of transmission waveforms are transmitted in segments according to the set time relationship, and complete near-ground low-altitude detection and medium-high-altitude detection within the same detection cycle; In one embodiment, a preset launch control strategy is used to schedule the first and second launch waveforms in a timely manner to achieve orderly switching and coordinated operation of wind field detection tasks at different altitudes.

[0040] In this embodiment, a complete detection cycle is divided into at least two consecutive time intervals, including a first time interval and a second time interval. The first time interval is used to carry out near-ground low-altitude detection missions, and the second time interval is used to carry out medium- and high-altitude detection missions. The two time intervals are arranged sequentially on the time axis according to a preset order, thereby forming a periodic and cyclical detection scheduling structure.

[0041] During the first time period, the radar transmitter continuously outputs the first transmitted waveform modulated by the first coded sequence. This continuous transmission process, based on the high pulse repetition frequency characteristics of the first transmitted waveform, increases the number of pulses transmitted per unit time, thereby improving the near-ground low-altitude echo sampling density to meet the detection requirements of drastic changes in the boundary layer wind field.

[0042] During the second time period, the radar transmitter continuously outputs a second transmitted waveform modulated by the second coded sequence. Since the second transmitted waveform corresponds to the mid-to-high altitude detection requirements, its pulse repetition frequency is relatively low. By extending the single transmission interval, the system can obtain a greater unambiguous detection range, thereby covering a higher airspace range.

[0043] The durations of the first and second time periods are respectively set as follows: and ,in and Configure according to the proportion of exploration missions. and satisfy ,in For a complete detection cycle. Through the analysis of... and The dynamic configuration allows the system to adjust the resource allocation between low-altitude fine-scale observations and high-altitude wide-area observations under different meteorological detection scenarios. For example, in severe convective weather monitoring scenarios, the proportion of the first time period can be appropriately increased to improve the sampling density of low-altitude wind shear and turbulent structures; in large-scale weather system observation scenarios, the proportion of the second time period can be appropriately increased to enhance the coverage of mid- and high-altitude wind fields.

[0044] By using the above time-segmented scheduling method, the two types of coded modulation waveforms can be transmitted alternately in an orderly manner within the same detection period, thus distinguishing different detection tasks from a time dimension. This provides a stable transmission timing basis for subsequent echo separation processing based on coding and demodulation, and improves the system's adaptability to collaborative detection of wind fields at multiple altitudes under complex meteorological conditions.

[0045] Step S4: Receive the target echo signal, and perform matched filtering on the target echo signal based on the first coding sequence and the second coding sequence respectively to separate and obtain the first echo data corresponding to the first transmitted waveform and the second echo data corresponding to the second transmitted waveform; In one embodiment, the radar receiver performs coding domain separation processing on the target echo signal to effectively distinguish and extract echoes corresponding to different transmitted waveforms.

[0046] The received target echo signal is represented in the discrete time domain as: ,in For discrete sampling index, It includes superimposed echo information from the first and second transmitted waveforms, as well as ambient noise components.

[0047] A first matched filter is constructed based on the first encoded sequence, and a first correlation operation is performed on the target echo signal to obtain the first processed output, as shown in the formula: A second matched filter is constructed based on the second encoded sequence, and a second correlation operation is performed on the target echo signal to obtain the second processed output, as shown in the formula: in, Indicates the first encoded sequence, Indicates the second encoded sequence, Indicates a lazy index. This represents the first processing output corresponding to the first encoded sequence. This represents the second processing output corresponding to the second encoded sequence; Because the first and second coding sequences differ in sequence structure and satisfy constraints in cross-correlation characteristics, the two types of codes can form different peak response positions in the output domain after correlation operation, thereby achieving the distinction between different waveform echoes.

[0048] In obtaining and Subsequently, data extraction processing is performed. The data extraction process includes detecting the position of the main peak in the relevant output sequence and extracting the effective echo component within the time delay window corresponding to the main peak, thereby obtaining the first echo data and the second echo data respectively. The first echo data corresponds to the scatterer echo information under the action of the first transmitted waveform, and the second echo data corresponds to the scatterer echo information under the action of the second transmitted waveform.

[0049] By using the above-mentioned separation method based on coded matched filtering, the mixed echo signals that were originally superimposed in the time domain can be effectively decoupled in the coding domain, thereby improving the separability of wind field echoes at different altitudes and providing a clear input data foundation for subsequent Doppler processing.

[0050] Step S5: Perform Doppler processing on the first echo data and the second echo data respectively to obtain the corresponding radial velocity, and obtain the near-ground low-altitude detection results and the mid-to-high-altitude detection results; In one embodiment, Doppler information extraction processing is performed on the separated first and second echo data to obtain wind field radial velocity information at different altitude levels, such as... Figure 2 As shown, it includes the following steps: Step S501: Standardize the first echo data and the second echo data in the distance dimension by unifying the sampling interval. The echo data is resampled to obtain a discrete echo sampling sequence, so that the data of each channel are consistent in time reference, so as to facilitate the subsequent unified distance mapping.

[0051] Step S502: Utilize the round-trip time delay relationship of radar electromagnetic wave propagation to map discrete sampling indices to physical distance cells. For the i-th sampling position, its corresponding detection distance... Determined according to the following formula: in, Indicates the first The detection range corresponding to each distance unit At the speed of light, This represents the round-trip propagation delay for the corresponding sampling point. Through this relationship, the conversion from the time-domain sampling index to the spatial distance unit is achieved, thereby establishing a distance-time correspondence.

[0052] Step S503: Divide the first and second echo data according to range cells, so that echo samples within the same range are grouped into the same range gate, thus forming an echo sequence structure organized by range gates. The data within each range gate are arranged sequentially according to the slow time dimension to ensure the continuity of subsequent phase evolution analysis.

[0053] Step S504: Based on the range gate partitioning, perform slow-time phase change analysis on the echo data within each range cell. Specifically, extract the phase difference of the continuous pulse echo signal to construct a phase change sequence, and perform spectral transformation processing based on this sequence to obtain the corresponding Doppler spectrum.

[0054] Spectral transformation can be implemented using the discrete Fourier transform, which essentially maps phase change information from the slow time domain to the frequency domain, thereby obtaining the Doppler frequency distribution characteristics of the target scatterer. In the Doppler spectrum, the spectral peak positions correspond to the dominant frequency components of the target main scatterer.

[0055] Step S505: Based on the Doppler frequency corresponding to the spectral peak Calculate radial velocity It satisfies the following relationship: in, Indicates the radial velocity of the target; The operating wavelength of the radar; This represents the Doppler frequency within the range cell.

[0056] Step S506: The radial velocity calculated from the first echo data is used as the near-surface low-altitude sounding result, and the radial velocity calculated from the second echo data is used as the mid-to-high-altitude sounding result, thus generating wind field velocity information outputs at different altitude levels. This processing flow structurally decouples range resolution and velocity extraction, improving the stability and consistency of radial velocity estimation under complex wind field conditions.

[0057] Step S6: Based on the distance distribution, the near-ground low-altitude detection results and the mid-to-high-altitude detection results are fused to generate the final wind field detection results; In one embodiment, the near-ground low-altitude sounding results and the mid-to-high-altitude sounding results are subjected to a distance-based hierarchical fusion process to form a complete vertical wind field structure output.

[0058] Based on the range gate division results, all range units are sorted from near to far according to the detection distance to construct a continuous range sequence. On this basis, according to the preset range gate division rules, the entire detection range is divided into three continuous range intervals, including the near range interval, the intermediate range interval, and the far range interval.

[0059] The near-distance range corresponds to the effective detection range of the first transmitted waveform. The echo signal-to-noise ratio is high and the distance resolution requirement is high in this area. The far-distance range corresponds to the effective detection range of the second transmitted waveform. This area is mainly used for acquiring large-scale wind fields in the mid-to-high altitude. The intermediate-distance range is the area where the first and second transmitted waveforms overlap in spatial coverage. Both types of echo data contribute to this area.

[0060] In the near-field range, only the radial velocity corresponding to the first echo data is used as the wind field output result for that range, in order to match the high-resolution detection characteristics near the ground.

[0061] In the long-range section, only the radial velocity corresponding to the second echo data is used as the wind field output result for that section, in order to meet the requirements of long-range detection in the mid-to-high altitude.

[0062] Within the intermediate distance range, radial velocity information from both the first and second echo data exists simultaneously. To avoid bias caused by signal-to-noise ratio or attenuation affecting data from a single channel in this region, a weighted fusion process is applied to the two types of radial velocities to obtain a more stable velocity estimation result. The weighted fusion expression is as follows: in, This indicates the radial velocity corresponding to the first echo data; This indicates the radial velocity corresponding to the second echo data; The weighting coefficient ranges from 0 to 1 and varies with the position of the distance cell within the overlapping interval. It is used to characterize the contribution ratio of the two types of waveforms at different distances. This represents the radial velocity result after fusion.

[0063] Through the above-mentioned partitioning and weighted fusion mechanism, different detection waveforms are output independently within their respective advantageous distance ranges, while information complementarity is achieved in overlapping areas, thereby reducing the impact of single waveform measurement deviation on the continuity of the overall wind field profile.

[0064] The output results of the near-distance interval, the fused results of the intermediate distance interval, and the output results of the far-distance interval are spliced ​​together in order of distance to form a complete and continuous vertical wind field profile, realizing a unified wind field expression from near the ground to the mid-to-high altitude.

[0065] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part 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 invention. 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.

[0066] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A wind field detection method based on a weather millimeter wave radar adjustable pulse waveform generation, characterized in that, Includes the following steps: Step S1: Construct the first and second transmission waveforms; Step S2: Load the first encoding sequence onto the first transmitted waveform and load the second encoding sequence onto the second transmitted waveform; Step S3: Based on the preset transmission control strategy, schedule the transmission of the first and second transmission waveforms after loading and encoding, so that the two types of transmission waveforms are transmitted in segments according to the set time relationship, and complete near-ground low-altitude detection and medium-high-altitude detection within the same detection cycle; Step S4: Receive the target echo signal, and perform matched filtering on the target echo signal based on the first coding sequence and the second coding sequence respectively to separate and obtain the first echo data corresponding to the first transmitted waveform and the second echo data corresponding to the second transmitted waveform; Step S5: Perform Doppler processing on the first echo data and the second echo data respectively to obtain the corresponding radial velocity, and obtain the near-ground low-altitude detection results and the mid-to-high-altitude detection results; Step S6: Based on the distance distribution, the near-ground low-altitude detection results and the mid-to-high-altitude detection results are fused to generate the final wind field detection results.

2. The wind field detection method based on the adjustable pulse waveform generation of the meteorological millimeter wave radar according to claim 1, characterized in that, The first transmitted waveform is used for low-altitude near-ground detection, and the second transmitted waveform is used for medium- and high-altitude detection. The pulse width of the first transmitted waveform is smaller than the pulse width of the second transmitted waveform, and the repetition frequency of the first transmitted waveform is higher than the repetition frequency of the second transmitted waveform.

3. The wind field detection method based on the adjustable pulse waveform generation of the meteorological millimeter wave radar according to claim 1, characterized in that, The steps of loading a first encoding sequence onto the first transmitted waveform and loading a second encoding sequence onto the second transmitted waveform specifically include: The first encoding sequence and the second encoding sequence are both pseudo-random sequences and correspond to different sequences respectively based on a preset rule. sequences; The first encoded sequence is used as the first control sequence to act on the first transmitted waveform, and the pulse state of the first transmitted waveform is serialized and modulated to form the first transmitted waveform after encoding and modulation. The second coded sequence is used as the second control sequence to act on the second transmitted waveform, and the pulse state of the second transmitted waveform is serialized and modulated to form the coded and modulated second transmitted waveform; Wherein the The sequence is generated by a shift register, and the sequence length satisfies Wherein is the shift register order, is the code sequence length.

4. The wind field detection method based on the adjustable pulse waveform generation of the meteorological millimeter wave radar according to claim 2, characterized in that, The first encoded sequence differs from the second encoded sequence in either the generator polynomial or the initial state. The first encoded sequence and the second encoded sequence satisfy a low cross-correlation characteristic, and the corresponding cross-correlation function is expressed as: wherein, and denote the first and second coded sequences, respectively, denotes a delay amount, denotes a sequence index, denotes a value of the first coded sequence at a th position, denotes a value of the second coded sequence at a th position, denotes a cross-correlation function value between the first coded sequence and the second coded sequence at a delay amount of . The absolute value of the cross-correlation function between the first encoded sequence and the second encoded sequence is less than a preset threshold.

5. The wind field detection method based on the adjustable pulse waveform generation of the meteorological millimeter wave radar according to claim 1, characterized in that, Step S3 specifically includes: A complete detection cycle is divided into at least two time periods, including a first time period and a second time period; During the first time period, the first transmitted waveform, which is encoded and modulated by the first coding sequence, is continuously transmitted. During the second time period, the second transmission waveform, encoded and modulated by the second coding sequence, is continuously transmitted; The first time period and the second time period are arranged in a preset order, and the duration of the first time period and the duration of the second time period are configured according to the detection requirements.

6. The wind field detection method based on adjustable pulse waveform generation from meteorological millimeter-wave radar according to claim 1, characterized in that, The step of performing matched filtering on the target echo signal based on the first encoding sequence and the second encoding sequence respectively, to separate and obtain the first echo data corresponding to the first transmitted waveform and the second echo data corresponding to the second transmitted waveform, specifically includes: The received target echo signal is represented as a discrete signal. ; A first matched filter is constructed based on the first encoded sequence, and a first correlation operation is performed on the target echo signal to obtain a first processed output, the formula of which is: A second matched filter is constructed based on the second encoded sequence, and a second correlation operation is performed on the target echo signal to obtain a second processed output, as shown in the formula: in, This represents the first encoded sequence. This represents the second encoded sequence. Indicates a lazy index. This represents the first processing output corresponding to the first encoded sequence. This represents the second processing output corresponding to the second encoded sequence; Data is extracted from the first processing output and the second processing output to obtain the first echo data and the second echo data.

7. The wind field detection method based on adjustable pulse waveform generation from meteorological millimeter-wave radar according to claim 1, characterized in that, The process of performing Doppler processing on the first echo data and the second echo data respectively to obtain the corresponding radial velocity, and thus obtaining near-ground low-altitude detection results and mid-to-high-altitude detection results, specifically includes: The first echo data and the second echo data are respectively processed by range cell grouping to form an echo sequence arranged by range gate; Phase change analysis is performed on the echo data in the slow time dimension within each range cell, and the phase change sequence is processed by spectral transformation to obtain the corresponding Doppler spectrum. The radial velocity is determined based on the Doppler frequency corresponding to the spectral peak in the Doppler spectrum. The radial velocity corresponding to the first echo data is taken as the near-ground low-altitude detection result, and the radial velocity corresponding to the second echo data is taken as the mid-to-high-altitude detection result.

8. The wind field detection method based on adjustable pulse waveform generation of meteorological millimeter-wave radar according to claim 7, characterized in that, The radial velocity With Doppler frequency The relationship between them is satisfied: in, For radar operating wavelength, This represents the Doppler frequency within the corresponding range cell.

9. A wind field detection method based on adjustable pulse waveform generation from meteorological millimeter-wave radar according to claim 7, characterized in that, The step of performing range cell grouping processing on the first echo data and the second echo data respectively to form an echo sequence arranged by range gates specifically includes: The first echo data and the second echo data are resampled according to a preset sampling interval to obtain a discrete echo sampling sequence; Based on the round-trip time delay relationship of radar signal propagation, the sampling index is converted into the corresponding range cell, where the first... The distances corresponding to each distance unit satisfy the following: in, Indicates the first The detection range corresponding to each distance unit At the speed of light, This indicates the round-trip propagation delay for the corresponding sampling point; The first echo data and the second echo data are divided according to the distance unit, so that echo data belonging to the same distance range are grouped into the same distance gate; The echo data within each distance gate are arranged in chronological order to form the corresponding distance gate echo sequence.

10. The wind field detection method based on adjustable pulse waveform generation of meteorological millimeter-wave radar according to claim 1, characterized in that, The process of fusing the near-surface low-altitude sounding results and the mid-to-high-altitude sounding results based on distance distribution to generate the final wind field sounding results specifically includes: Based on the distance gate division results, all distance units are sorted from near to far according to the detection distance, and the distance units are divided into three continuous intervals according to the preset distance gate division rules, including the near distance interval, the middle distance interval and the far distance interval. Wherein, the near-range interval corresponds to the range gate range of the first transmitted waveform, the far-range interval corresponds to the range gate range of the second transmitted waveform, and the intermediate range is the range gate range of the overlap between the first transmitted waveform and the second transmitted waveform; Within the short-range interval, the radial velocity corresponding to the first echo data is used as the output wind field result; Within the long-distance range, the radial velocity corresponding to the second echo data is used as the output wind field result; Within the intermediate distance range, the radial velocities corresponding to the first echo data and the second echo data are weighted and fused to obtain the fused radial velocity. The weighted fusion process is calculated using the following formula: in, This represents the radial velocity corresponding to the first echo data. This indicates the radial velocity corresponding to the second echo data. These are weighting coefficients related to the location of the distance cell; Indicates the fusion radial velocity; The output results of each distance interval are combined to form a complete vertical wind field profile.

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