A dual-frequency ADCP adaptive current measurement method and system

Abstract

This invention proposes a dual-frequency ADCP adaptive flow measurement method and system. The method includes: acquiring environmental characteristic parameters of the measurement water area in real time, including water depth data, high and low frequency echo intensities, and high and low frequency signal-to-noise ratios; selecting a corresponding initial working mode based on a preset depth-first rule and the environmental characteristic parameters; wherein the initial working mode presets specified high and low frequency bands and a specified flow measurement mode; calculating a composite quality index based on the high and low frequency echo intensities and the high and low frequency signal-to-noise ratios, verifying the high and low frequency bands of the initial working mode based on the composite quality index, and switching to a target frequency band based on the verification results; performing quality detection on the target frequency band based on the signal-to-noise ratios of multiple depth units in the target frequency band, locking or switching the flow measurement mode based on the quality detection results to obtain the target flow measurement mode; and measuring the flow in the measurement water area according to the target frequency band and the target flow measurement mode to obtain the flow measurement results, thereby improving the flow measurement accuracy.

Description

Technical Field

[0001] This invention relates to the field of adaptive intelligent flow measurement technology, and in particular to a dual-frequency ADCP adaptive flow measurement method and system. Background Technology

[0002] Existing acoustic Doppler current profilers (ADCPs) mostly use fixed frequencies (such as 300kHz, 600kHz, or 1200kHz) for current velocity profile measurements. High-frequency signals have advantages in spatial resolution, but propagation loss is significant in deep water or water bodies with high sediment content, and the effective measurement range is easily insufficient due to excessive signal attenuation. Although low-frequency signals have stronger penetration and measurement range advantages, their spatial resolution is lower, and echo saturation and near-field measurement blind zones are prone to occur in shallow water or low-velocity areas.

[0003] Due to significant differences in acoustic attenuation characteristics and signal-to-noise ratio response under different flow field environments, traditional adaptive flow measurement methods based on a single frequency struggle to meet the dual requirements of high resolution and long range when dealing with the complex and variable hydrological conditions faced by mobile ADCPs. Therefore, there is an urgent need to develop a novel measurement method that can adaptively select a frequency measurement strategy based on environmental characteristics and integrate multi-frequency band information for flow velocity inversion. Summary of the Invention

[0004] This invention provides a dual-frequency ADCP adaptive current measurement method and system to solve the problems existing in related technologies. The technical solution is as follows: In a first aspect, embodiments of the present invention provide a dual-frequency ADCP adaptive current measurement method, comprising: Real-time acquisition of environmental characteristic parameters of the measured water area, including water depth data, high and low frequency echo intensity of multiple depth cells, and high and low frequency signal-to-noise ratio of multiple depth cells; Based on the preset depth-first rule, the corresponding initial working mode is selected according to the environmental characteristic parameters; the initial working mode is preset with specified high and low frequency bands and specified flow measurement mode. The composite quality index is calculated based on the high and low frequency echo intensity and the high and low frequency signal-to-noise ratio. The high and low frequency bands of the initial working mode are verified based on the composite quality index. The target frequency band is then switched based on the verification results. Based on the signal-to-noise ratio of multiple deep cells in the target frequency band, the target frequency band is quality detected, and the flow measurement mode is locked or switched according to the quality detection results to obtain the target flow measurement mode. The flow is measured in the target water area according to the target frequency band and the target flow measurement mode, and the flow measurement results are obtained.

[0005] In one implementation, calculating the composite quality index based on the high and low frequency echo intensities and the high and low frequency signal-to-noise ratio includes: Based on the high-frequency signal-to-noise ratio of multiple depth cells, a first normalization function is used to map it to a first normalized value; based on the high-frequency echo intensity of multiple depth cells, a second normalization function is used to map it to a second normalized value, and the first normalized value and the second normalized value are weighted and combined to obtain a high-frequency composite quality index. Based on the low-frequency signal-to-noise ratio of multiple depth cells, a third normalized value is obtained by mapping the first normalization function; based on the low-frequency echo intensity of multiple depth cells, a fourth normalized value is obtained by mapping the second normalization function; and the third and fourth normalized values ​​are weighted and combined to obtain the low-frequency composite quality index.

[0006] In one implementation, the high and low frequency bands of the initial operating mode are verified based on composite quality indicators, and the switching to the target frequency band is performed based on the verification results, including: When the value of the high-frequency composite quality index minus the low-frequency composite quality index is greater than the preset threshold, the high-frequency band is switched to the target frequency band. When the value of the low-frequency composite quality index minus the high-frequency composite quality index is greater than the preset threshold, the low-frequency band is switched to the target frequency band.

[0007] In one implementation, based on the signal-to-noise ratio of multiple deep cells in the target frequency band, quality detection is performed on the target frequency band. The current measurement mode is then locked or switched according to the quality detection results, resulting in the target current measurement mode, which includes: The number of depth cells with a signal-to-noise ratio greater than or equal to a preset available threshold in the target frequency band among all effective depth cells is counted, and the proportion of the depth cells to the total number of all effective depth cells is calculated. If the ratio is greater than or equal to a preset ratio threshold, then the pulse coherence mode is selected as the target flow measurement mode for the target frequency band; if the ratio is less than the preset ratio threshold, then the broadband mode is selected as the target flow measurement mode.

[0008] In one implementation, it further includes: When the absolute value of the high-frequency composite quality index minus the low-frequency composite quality index is less than or equal to a preset threshold, and the high-frequency signal-to-noise ratio is less than the available threshold and the low-frequency signal-to-noise ratio is less than the available threshold, the target frequency band and target flow measurement mode are determined based on the dual-frequency fusion strategy.

[0009] In one implementation, determining the target frequency band and target current measurement mode based on a dual-frequency fusion strategy includes: The weighting coefficient is determined based on the proportion of the effective range of high frequency in the total water depth, and the entire measurement area is divided into upper and lower layers based on the weighting coefficient. Switch the target frequency band corresponding to the upper region to the high frequency band, switch the target frequency band corresponding to the lower region to the low frequency band, and synchronously determine the flow measurement mode corresponding to the broadband mode as the target flow measurement mode of the upper region and the target flow measurement mode of the lower region.

[0010] In one implementation, the environmental characteristic parameters also include flow velocity; when the water depth data is less than or equal to 6m and the flow velocity is greater than or equal to 0.4m / s, the target frequency band of the default initial working mode is the high frequency band, and the target flow measurement mode is the broadband mode.

[0011] Secondly, embodiments of the present invention provide a dual-frequency ADCP adaptive flow measurement system, comprising: The acquisition unit is used to acquire environmental characteristic parameters of the measured water area in real time. The environmental characteristic parameters include water depth data, high and low frequency echo intensity of multiple depth units, and high and low frequency signal-to-noise ratio of multiple depth units. The mode selection unit is used to select the corresponding initial working mode according to the preset depth priority rule and environmental characteristic parameters; wherein, the initial working mode is preset with specified high and low frequency bands and specified flow measurement mode. The frequency band verification unit is used to calculate the composite quality index based on the high and low frequency echo intensity and the high and low frequency signal-to-noise ratio, verify the high and low frequency bands of the initial working mode based on the composite quality index, and switch to the target frequency band according to the verification results. The quality detection unit performs quality detection on the target frequency band based on the signal-to-noise ratio of multiple deep units in the target frequency band, and locks or switches the flow measurement mode according to the quality detection results to obtain the target flow measurement mode. The flow measurement main control unit measures the flow in the water area according to the target frequency band and the target flow measurement mode, and outputs the flow measurement results.

[0012] Thirdly, embodiments of the present invention provide an electronic device comprising a memory and a processor. The memory and the processor communicate with each other via an internal connection path. The memory stores instructions, and the processor executes the instructions stored in the memory. When the processor executes the instructions stored in the memory, it causes the processor to perform the method described in any of the above embodiments.

[0013] Fourthly, embodiments of the present invention provide a computer-readable storage medium that stores a computer program, wherein when the computer program is run on a computer, the methods in any of the embodiments described above are executed.

[0014] The advantages or beneficial effects of the above technical solutions include at least the following: This invention dynamically switches between high and low frequency bands of the default initial working mode based on real-time environmental characteristic parameters and composite quality indicators. At the same time, it performs quality detection on the target frequency band to determine the appropriate flow measurement mode for the current environment. This maintains high resolution in shallow water and continuous measurement range and stable signal in deep water or high attenuation environments, ensuring the reliability and consistency of flow measurement results under different environmental conditions and improving flow measurement accuracy.

[0015] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the invention will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0016] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in the invention and should not be construed as limiting the scope of the invention.

[0017] Figure 1 This is a flowchart illustrating the dual-frequency ADCP adaptive current measurement method of the present invention. Figure 2 This is a schematic diagram of the dual-frequency ADCP adaptive flow measurement system of the present invention; Figure 3 This is a structural block diagram of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0018] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0019] Example 1 Currently, existing single-frequency ADCPs typically use a fixed operating frequency (such as 300kHz, 600kHz, or 1200kHz) for flow velocity profile measurements. This has the following drawbacks: First, the applicable range of measurements is still limited by the physical limitations of single-frequency devices, making it impossible to simultaneously achieve both measurement depth and resolution. Because a fixed frequency restricts measurement coverage, single-frequency equipment typically operates at a fixed center frequency. While high-frequency signals offer high spatial resolution, they suffer significant propagation losses in deep water or high-sand environments, easily leading to signal attenuation and insufficient range. Low-frequency signals, although possessing strong penetrating power, suffer from poor resolution and near-field accuracy, often exhibiting echo saturation or blind zones in shallow water or low-flow-velocity areas.

[0020] Second, multi-scale data fusion cannot be achieved. The profile data comes from only a single frequency band and lacks complementary information between multiple frequencies, making it difficult to achieve high-precision profile reconstruction or bottom tracking enhancement.

[0021] Third, the signal-to-noise ratio adjustment relies on a single channel and lacks self-compensation capabilities. When the signal-to-noise ratio is too low, it can only passively increase the layer thickness (reduce resolution) and cannot actively increase signal energy or change propagation characteristics, nor can it adapt the frequency adjustment to different acoustic characteristics of water bodies (such as sediment concentration and bubble layer).

[0022] To address the aforementioned issues, this embodiment provides a dual-frequency ADCP adaptive flow measurement method. This method integrates transducer channels for two independent high and low frequency bands, combined with real-time environmental parameters (including water depth, flow velocity, signal-to-noise ratio, echo intensity, etc.), to achieve automatic switching between frequency bands and complementary high- and low-frequency measurements. This overcomes the limitations of existing single-frequency adaptive flow measurement technologies, such as limited measurement range, unstable signal-to-noise ratio, and resolution constrained by the environment. By integrating transducer channels for two independent high and low frequency bands and combining real-time environmental parameters (including water depth, flow velocity, signal-to-noise ratio, echo intensity, etc.), the system achieves automatic switching between frequency bands and complementary high- and low-frequency measurements. The system can automatically and dynamically switch between high and low frequencies based on real-time monitored signal quality and water attenuation characteristics, thereby maintaining high resolution in shallow water and continuous measurement range and stable signal in deep water or high-attenuation environments, ensuring the reliability and consistency of flow measurement results under different environmental conditions.

[0023] like Figure 1 As shown, the dual-frequency ADCP adaptive current measurement method in this embodiment specifically includes the following steps: Step S1: Real-time acquisition of environmental characteristic parameters of the measured water area, including water depth data, high and low frequency echo intensity of multiple depth units, and high and low frequency signal-to-noise ratio of multiple depth units.

[0024] This embodiment integrates two independent frequency band transducer channels (high-frequency and low-frequency) to simultaneously transmit and receive signals, acquiring the echo intensity and signal-to-noise ratio of high and low frequencies at each depth cell. It also acquires real-time data on the current effective water depth and average current velocity to obtain environmental characteristic parameters. These environmental characteristic parameters include the high-frequency echo intensity E at depth cell z. H Low-frequency echo intensity E LF High-frequency signal-to-noise ratio (SNR) HF (z) Low-frequency signal-to-noise ratio (SNR) LF (z), water depth data H, and average flow velocity V, etc., are used to construct an environmental feature vector.

[0025] It should be noted that in this embodiment, high frequency refers to 3.0MHz and low frequency refers to 1.2MHz.

[0026] Step S2: Based on the preset depth-first rule, select the corresponding initial working mode according to the environmental characteristic parameters; wherein, the initial working mode is preset with specified high and low frequency bands and specified flow measurement mode.

[0027] This embodiment pre-sets multiple working modes, such as: M1 mode is a high-frequency (3.0MHz) pulse coherent mode; M2 mode is a low-frequency (1.2MHz) pulse coherent mode; M3 mode is a high-frequency (3.0MHz) broadband mode; M4 mode is a low-frequency (1.2MHz) broadband mode.

[0028] Among them, pulse coherence and broadband belong to the current measurement mode.

[0029] High-frequency sound waves attenuate quickly but have high resolution, while low-frequency sound waves attenuate slowly but have low resolution. Therefore, a depth-priority rule is established beforehand. The logic is that in shallow water, signal attenuation is not the primary concern, so prioritizing high frequencies can fully utilize their high resolution advantage to accurately measure flow velocity profiles and avoid the insufficient resolution of low frequencies in shallow water. In deep water, ensuring the signal can propagate to the bottom and return effectively (i.e., ensuring the measurement range) is the primary task. Low-frequency signals have strong penetrating power and can effectively avoid excessive attenuation of high-frequency signals in deep water, ensuring the acquisition of complete water column data. The definitions of shallow and deep water can be pre-set using empirical thresholds, for example, less than or equal to 3 meters is considered shallow water, and greater than 3 meters is considered deep water.

[0030] In this embodiment, based on a preset depth-priority rule, the corresponding operating mode is selected as the initial operating mode according to the water depth data. In this embodiment, if the water depth data H is less than or equal to 3.0m, the default initial operating mode is M1 mode (3.0MHz, pulsed coherent mode, cell layer thickness 0.02m); if the water depth data H is greater than 3m but less than or equal to 6m, the default initial operating mode is M2 mode (1.0 MHz, pulsed coherent mode, 0.06m cell); if the water depth data H is less than or equal to 6m and the average flow velocity V is greater than or equal to 0.4m / s, the default initial operating mode is M3 mode (3.0MHz, broadband mode); if the water depth data H is greater than 6m, the default initial operating mode is M4 mode (1.2MHz, broadband mode).

[0031] It should be noted that the pulsed coherent measurement method relies on phase / coherence to measure low speeds and small wavelength changes. It is suitable for low-speed environments but has a speed limit. When the flow velocity increases, the pulsed coherent processing will encounter problems such as phase wrapping / correlation decline, resulting in the failure or instability of coherent velocity measurement. Therefore, it is necessary to switch to the broadband mode (M3 / M4) to improve the range and stability of speed measurement. When the flow velocity is lower than 0.4 m / s, the pulsed coherent mode can operate reliably, and its speed measurement accuracy and stability can be fully exerted. Therefore, the system can preferably maintain this mode. When the flow velocity is greater than or equal to 0.4 m / s, phase ambiguity and signal decoherence will be caused, and at this time, it will be adaptively switched to the broadband mode to expand the measurement range.

[0032] When the M3 mode is the initial working mode, the cell size is selected according to the water depth H: When H ≤ 3 m, the cell size is 0.1 m; When 3 < H ≤ 6 m, the cell size is 0.2 m.

[0033] Similarly, in the M4 mode, the cell size is also selected according to the water depth H: When H < 10 m, the cell size is 0.5 m; When 10 ≤ H < 20 m, the cell size is 1.0 m; When H ≥ 20 m, the cell size is 2.0 m.

[0034] In this embodiment, the adjustment of the cell size and the selection of the working mode together constitute a two-layer optimization strategy. Specifically, the mode selection is used to determine the basic measurement method (such as the pulsed coherent mode or the broadband mode) and the working frequency band (high frequency or low frequency), which determines the basic performance boundaries of the system (such as the maximum measurement range, the highest resolution, and the best low-speed performance). The adjustment of the cell size, on the other hand, performs fine performance optimization under the selected working mode. It fine-tunes the pair of contradictions of "resolution - signal-to-noise ratio" according to the real-time water depth and signal conditions within the boundaries set by this mode to achieve the optimal performance under the current conditions.

[0035] Step S3: Calculate the composite quality index based on the high-frequency and low-frequency echo intensities and the high-frequency and low-frequency signal-to-noise ratios, verify the high and low frequency bands of the initial working mode based on the composite quality index, and switch to the target frequency band according to the verification result.

[0036] In this embodiment, the initial working mode is verified and corrected through the composite quality index to determine the target frequency band. Among them, the composite quality index includes the high-frequency composite quality index (Q HF ), and the low-frequency composite quality index (Q LF ).

[0037] The calculation method of the high-frequency composite quality index is: Based on the high-frequency signal-to-noise ratio of multiple depth cells, the eigenvalue is mapped to a first normalized value using a first normalization function; similarly, based on the high-frequency echo intensity of multiple depth cells, it is mapped to a second normalized value using a second normalization function; subsequently, the first and second normalized values ​​are weighted and combined to obtain the high-frequency composite quality index Q. HF Its expression is: Q HF =α•normSNR HF +β•normE HF ; In the formula, normSNR is the first normalization function that linearly normalizes the signal-to-noise ratio to the [0,1] interval, mapping the SNR of all depth cells in the same frequency band to the [0,1] interval for cross-band comparison. Its expression is as follows: ; In the formula, SNR represents the raw signal-to-noise ratio value actually measured at a specific frequency band and depth cell; SNR max Normalized upper limit benchmark; SNR min This serves as the lower bound benchmark for normalization.

[0038] normE is the second normalization function that normalizes the original value to [0,1]. Since echo intensity reflects the reflection intensity of scatterers such as suspended sediment, bubbles, and bottom sediment in the water, it spans a large range, and high-value areas are often saturated while low-value areas are dominated by noise. Direct linear normalization can easily lead to strong echoes being overly concentrated (close to 1) and weak echo areas being insensitive to changes (close to 0). Therefore, the nonlinear normalization function Sigmoid is used to process the echo intensity of all depth units, avoiding the insensitivity of linear normalization at extreme values. Its expression is: ; In the formula, k is an empirical adjustment coefficient, which can be temporarily set to 0.1; E is the original echo intensity actually measured in a specific frequency band and a specific depth unit; E0 is the median point of the echo intensity preset based on the frequency band, which is used to reflect the boundary of the signal intensity transition. For high frequency, E0 is selected as 100dB, and for low frequency, E0 is selected as 95dB.

[0039] Similarly, the calculation method for low-frequency composite quality indicators is as follows: Based on the low-frequency signal-to-noise ratio of multiple depth cells, a third normalized value is obtained by mapping the low-frequency echo intensity of multiple depth cells to a fourth normalized value through a second normalized function. The third and fourth normalized values ​​are then weighted and combined to obtain the low-frequency composite quality index Q. LF Its expression is: Q LF =α•normSNR LF +β•normE LF ; In the above formula, α is the SNR weighting coefficient, which represents the system's confidence in "signal stability". The larger α is, the more it tends to select frequency bands with higher signal-to-noise ratio; β is the echo intensity weighting coefficient, which represents the system's confidence in "target scattering characteristics". The larger β is, the more it values ​​echo intensity (i.e., scatterer concentration and reflection intensity).

[0040] The high-frequency composite quality index Q was obtained through the above calculations. HF and low-frequency composite quality index Q LF Calculate the difference between the two to determine the target frequency band; the details are as follows: When the high-frequency composite quality index Q HF Subtract the low-frequency composite quality index Q LF The value is greater than a preset threshold, which can be adjusted according to the actual situation. In this embodiment... ,like If so, the high-frequency band will be switched to the target frequency band first.

[0041] If the low-frequency composite quality index Q LF Subtract the high-frequency composite quality index Q HF The value is greater than the preset threshold. , If the frequency band is low, the target frequency band will be switched first. Otherwise, the dual-frequency fusion mode will be entered.

[0042] Step S4: Based on the signal-to-noise ratio of multiple deep cells in the target frequency band, perform quality detection on the target frequency band, and lock or switch the flow measurement mode according to the quality detection results to obtain the target flow measurement mode.

[0043] In this embodiment, the target frequency band selected in step S3 is checked for quality. If the target frequency band is high frequency, the high frequency quality is checked; if the target frequency band is low frequency, the low frequency quality is checked.

[0044] The quality inspection method is as follows: The number of depth cells with a signal-to-noise ratio greater than or equal to a preset available threshold in the target frequency band among all effective depth cells is counted, and the proportion of the number of depth cells to the total number of all effective depth cells is calculated. If the proportion is greater than or equal to a preset proportion threshold, the pulse coherence mode is selected as the target current measurement mode for the target frequency band; if the proportion is less than the preset proportion threshold, the broadband mode is selected as the target current measurement mode.

[0045] For example: In scenarios where the water depth H is less than or equal to 3m, the default initial operating mode is M1 mode (3.0 MHz, pulse coherence). If the target frequency band is a high-frequency band, the preset available threshold is SNR. marginal The preset threshold ratio is 60%; at this point, the high-frequency quality is checked, and the high-frequency signal-to-noise ratio (SNR) is calculated. HF Greater than or equal to the available threshold SNR marginal If the depth cell ratio is greater than 60%, then the pulse coherence mode is selected as the target current measurement mode, i.e., the M1 mode is locked; otherwise, it is considered that the high-frequency band quality is poor, and the broadband mode of the high-frequency band is selected, i.e., the M1 mode is reverted to the M3 mode (3.0 MHz, broadband).

[0046] If the target frequency band is a low-frequency band, then check the low-frequency quality; if the low-frequency signal-to-noise ratio (SNR) is... LF Greater than or equal to the available threshold SNR marginal If the depth cell ratio is greater than 60%, then M2 mode is locked; otherwise, the low-frequency quality is poor, and it reverts to M4 mode.

[0047] In scenarios where the water depth H is greater than 3m and less than or equal to 6m, the default initial operating mode is M2 mode (1.2MHz, pulsed coherence, 0.06m cell). In the 0~3m shallow region, the SNR of over 85% of the cell layers is [not specified]. HF Greater than SNR LF And achieve SNR good This means that the high-frequency signal-to-noise ratio is much better than the low-frequency signal-to-noise ratio at this point, and it's possible to switch to the high-frequency M1 mode. Verification and correction are performed based on composite quality indicators to determine if a frequency switch is necessary. If the target frequency band is high-frequency, the high-frequency quality is checked; if the high-frequency signal-to-noise ratio (SNR) of more than 60% of the depth cell layers is... HF Greater than or equal to the available threshold SNR marginal If the target frequency band is low, check the low-frequency quality. If the low-frequency signal-to-noise ratio (SNR) of more than 60% of the deep cell layers is high, then lock the M1 mode; otherwise, if the high-frequency quality is poor, switch to the M3 mode. If the target frequency band is low, check the low-frequency quality. LF Greater than or equal to the available threshold SNR marginal If the M2 mode is locked, then the low-frequency quality will be poor, and the mode will revert to M4 mode.

[0048] In scenarios where water depth H is less than or equal to 6m and current velocity V is greater than or equal to 0.4m / s, the default initial operating mode is M3 mode. Verification and correction are performed based on composite quality indicators to determine if a frequency band switch is necessary. High-frequency / low-frequency quality is checked according to the target frequency band. When the signal-to-noise ratio (SNR) of the high-frequency or low-frequency channel is lower than the marginal usable threshold of 10dB in more than 60% of the effective survey layers, the system will sequentially execute the following signal enhancement steps according to a preset strategy to improve the SNR level: Step 1: Increase the number of signal averaging cycles The system prioritizes improving the signal-to-noise ratio (SNR) by increasing the number of signal averaging iterations. The adjustment follows the principle of "approximately 3 dB SNR improvement per step," meaning that doubling the number of averaging iterations is expected to improve the SNR by approximately 3 dB. The adjustment sequence is as follows: 1. Increase the average number of attempts from the default 2 to 4; 2. If the signal-to-noise ratio still does not meet the requirements, the average number of times is further increased to the upper limit (up to 8 times for high frequency and up to 16 times for low frequency).

[0049] Step 2: Increase the level of the emitted sound source If the signal-to-noise ratio still fails to meet the target after increasing the averaging steps, the system will switch to transmit power adjustment. In this stage, the transmit power is gradually increased by doubling the power per step (i.e., increasing by about 3 dB). The power increase for both high-frequency and low-frequency channels will be performed in a maximum of 2 steps to avoid excessive energy consumption and potential sound source interference.

[0050] In this embodiment, the dual-frequency fusion mode refers to the system's decision not to choose one over the other when the performance of either the high or low frequency bands is unsatisfactory individually and their performance is similar. Instead, the system simultaneously activates both frequency bands, dividing the water column into upper and lower layers and assigning each layer its most suitable frequency band for measurement. The dual-frequency fusion mode is activated when the following triggering conditions are met: When the absolute value of the high-frequency composite quality index minus the low-frequency composite quality index is less than or equal to a preset threshold, and the high-frequency signal-to-noise ratio is less than the available threshold and the low-frequency signal-to-noise ratio is less than the available threshold, the target frequency band and target flow measurement mode are determined based on the dual-frequency fusion strategy.

[0051] Among them, if the absolute value of the high-frequency composite quality index minus the low-frequency composite quality index is less than or equal to the preset threshold, it means that the overall quality index of the two frequency bands is very close and difficult to choose; if the high-frequency signal-to-noise ratio is less than the usable threshold and the low-frequency signal-to-noise ratio is less than the usable threshold, it means that the high-frequency quality and low-frequency quality of the entire profile or most units are poor.

[0052] At this point, the entire water depth is divided into two zones: the upper zone (0 ~ W). HF * H: Measurements are performed by the high-frequency (HF) channel; lower region (W HF * H ~ H): Measurements are performed by the low-frequency (LF) channel. Wherein, W HF It is a weighting coefficient less than 0.5, representing the proportion of the effective range of high frequency measurements in the total water depth.

[0053] The upper and lower layers employ different operating modes and unit layer thicknesses. The upper layer uses a high-frequency default broadband mode (M3 mode), controlling the high-frequency transducer channel to measure the flow velocity in the upper water area. The unit layer thickness of its depth cells is based on the depth of the upper water area (W). HF * H) Perform adaptive configuration.

[0054] The lower region employs a low-frequency default broadband mode (M4 mode), controlling the low-frequency transducer channel to measure the flow velocity in the lower water layer. The cell thickness of its depth unit is based on the depth of the lower water layer (HW). HF * H) Perform adaptive configuration.

[0055] The configuration rules for unit layer thickness are as follows: the smaller the water depth range, the thinner the configured unit layer thickness, in order to improve resolution; the larger the water depth range, the thicker the configured unit layer thickness, in order to ensure measurement range and signal stability.

[0056] Step S5: Measure the flow in the water area according to the target frequency band and the target flow measurement mode to obtain the flow measurement results.

[0057] After determining the working mode, i.e. the target frequency band (high frequency or low frequency) and the target flow measurement mode (pulse coherent or broadband), the high-frequency transducer channel or the low-frequency transducer channel is controlled to perform flow measurement operation according to the selected target frequency band and target flow measurement mode to obtain the flow measurement result.

[0058] This embodiment can automatically and dynamically switch between high and low frequencies based on real-time monitored environmental characteristic parameters, thereby maintaining high resolution in shallow water and maintaining continuous measurement range and stable signal in deep water or high attenuation environments, ensuring the reliability and consistency of flow measurement results under different environmental conditions, thereby improving the accuracy of flow measurement.

[0059] Example 2 like Figure 2 As shown, this embodiment provides a dual-frequency ADCP adaptive flow measurement system, which includes a transmitter module, a transceiver converter module, an AD sampling module, a first processing module, a second processing module, and a control and communication module.

[0060] The control and communication module is the main control unit of the system, which executes the dual-frequency ADCP adaptive current measurement method as described in Example 1. Specifically, the control and communication module includes: The acquisition unit is used to acquire environmental characteristic parameters of the measured water area in real time. The environmental characteristic parameters include water depth data, high and low frequency echo intensity of multiple depth units, and high and low frequency signal-to-noise ratio of multiple depth units. The mode selection unit is used to select the corresponding initial working mode according to the preset depth priority rule and environmental characteristic parameters; wherein, the initial working mode is preset with specified high and low frequency bands and specified flow measurement mode. The frequency band verification unit is used to calculate the composite quality index based on the high and low frequency echo intensity and the high and low frequency signal-to-noise ratio, verify the high and low frequency bands of the initial working mode based on the composite quality index, and switch to the target frequency band according to the verification results. The quality detection unit performs quality detection on the target frequency band based on the signal-to-noise ratio of multiple deep units in the target frequency band, and locks or switches the flow measurement mode according to the quality detection results to obtain the target flow measurement mode. The flow measurement master control unit generates and sends control commands to the transmitter module based on the target frequency band and the target flow measurement mode.

[0061] In this embodiment, the control and communication module is responsible for overall system coordination, frequency band mode scheduling, parameter configuration, and external communication. Based on real-time monitored water environment data (including water depth, flow velocity, signal-to-noise ratio, echo intensity, etc.), this module dynamically determines the current operating mode and transmission parameters, and generates and sends control commands to the transmitter module.

[0062] The transmitter module, connected to the control and communication module, uses FPGA control to achieve precise synchronization of transmission timing and channel management. This module can execute alternating or parallel transmission of high- and low-frequency pulse signals according to control commands, driving the acoustic emission arrays in the high-frequency and low-frequency transducer channels. The transmitted signal is radiated into the water body via the transceiver module and received by the same transducer upon echo arrival. The system employs different operating modes under different environments: in shallow, high-resolution environments, only the high-frequency channel is activated; in deep, high-attenuation environments, it switches to the low-frequency channel; in complex environments, a dual-frequency collaborative fusion transmission mode is used to achieve complementary high- and low-frequency current measurement. The transceiver transducer, connected to the transmitter module and AD sampling module, is used for transmitting acoustic signals and receiving echoes. The transceiver transducer features a dual-frequency composite transducer array structure, integrating four high-frequency 3MHz transducers, four low-frequency 1.2MHz transducers, and a 0.6MHz vertical beam within the same probe. The system achieves frequency band isolation and mutual interference suppression, obtaining stable echo signals in both shallow and deep water conditions, realizing adaptive current measurement across all water depths while maintaining both measurement range and resolution. The AD sampling module, connected to the transceiver converter and the first processing module, is used to synchronously sample and process the received high- and low-frequency analog echo signals. After AD sampling, two digital signal streams, one high-frequency and one low-frequency, are generated and sent to the first processing module. The first processing module performs matched filtering, demodulation, and signal feature extraction on the input high- and low-frequency digital signal streams to obtain water environment characteristic parameters such as signal-to-noise ratio and frequency shift, and sends these parameters to the second processing module. The second processing module analyzes the received water environment characteristic parameters and generates the final water environment information, while simultaneously performing dual-frequency data fusion and flow measurement result calculation. The first processing module (signal processing layer), implemented by an FPGA, performs high-speed parallel low-level signal processing tasks. It performs matched filtering and demodulation on high- and low-frequency digital signal streams, performs coherent integration, envelope detection, and frequency shift extraction; calculates characteristic parameters such as signal-to-noise ratio (SNR) and beam velocity for each beam signal; and performs preprocessing and feature extraction on the echo signal, including depth, flow velocity, and SNR. After processing, the first module outputs a feature parameter vector P = [H, SNR, E, V0] and transmits the result to the second processing module.

[0063] The second processing module (intelligent decision-making and fusion layer), implemented by a DSP or high-performance processor, is primarily used to execute adaptive frequency measurement decisions and dual-frequency fusion algorithms. Based on the water environment characteristic parameters output by the first processing module, this module dynamically determines the current operating mode (high frequency, low frequency, or fusion) and implements dual-frequency velocity data fusion based on a weighted strategy. High-frequency data is prioritized in shallow water conditions, while low-frequency data is prioritized in deep water or high-attenuation conditions. When the environment is complex or the signal is unstable, a high-low frequency weighted fusion algorithm is executed to improve the integrity and continuity of the velocity profile. The second processing module simultaneously outputs the final velocity profile results and environmental information and uploads the results to the control and communication module.

[0064] After receiving the optimized parameters, the control module updates the system status in real time, including: reconfiguring the transmission parameters, adjusting the sampling rate, changing the frequency channel activation status, changing the signal working mode; and sending the current flow measurement status and flow velocity profile data to the external host.

[0065] This embodiment of the dual-frequency adaptive flow measurement system achieves signal adaptive optimization, high-precision flow profile measurement, and balance of range and resolution under different hydrological environments through the coordinated operation of high and low frequency transducers.

[0066] It should be noted that the module functions in the system of this embodiment can be found in the corresponding descriptions in the above methods, and will not be repeated here.

[0067] Example 3 This embodiment provides an electronic device. Figure 3 A structural block diagram of an electronic device according to an embodiment of the present invention is shown. Figure 3 As shown, the electronic device includes a memory 100 and a processor 200. The memory 100 stores a computer program that can run on the processor 200. When the processor 200 executes the computer program, it implements the dual-frequency ADCP adaptive current measurement method in the above embodiment. The number of memories 100 and processors 200 can be one or more.

[0068] The electronic device also includes: The communication interface 300 is used to communicate with external devices and perform data exchange and transmission.

[0069] If the memory 100, processor 200, and communication interface 300 are implemented independently, they can be interconnected via a bus to communicate with each other. This bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. This bus can be divided into address bus, data bus, control bus, etc.

[0070] Optionally, in a specific implementation, if the memory 100, processor 200, and communication interface 300 are integrated on a single chip, then the memory 100, processor 200, and communication interface 300 can communicate with each other through an internal interface.

[0071] This invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method provided in this invention.

[0072] This invention also provides a chip, which includes a processor for calling and executing instructions stored in a memory, causing a communication device on which the chip is installed to perform the method provided in this invention.

[0073] This invention also provides a chip, including: an input interface, an output interface, a processor, and a memory. The input interface, output interface, processor, and memory are connected through an internal connection path. The processor is used to execute code in the memory. When the code is executed, the processor is used to execute the method provided in this invention.

[0074] It should be understood that the aforementioned processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. General-purpose processors can be microprocessors or any conventional processor. It is worth noting that the processor can be a processor supporting the Advanced Reduced Instruction Set Computing (RISC) machine (ARM) architecture.

[0075] Further, optionally, the aforementioned memory may include read-only memory and random access memory, and may also include non-volatile random access memory. The memory may be volatile or non-volatile, or may include both. Non-volatile memory may include read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may include random access memory (RAM), which serves as an external cache. Many forms of RAM are available by way of example, but not limitation. Examples include static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0076] In the above embodiments, implementation can be achieved, in whole or in part, by software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the present invention is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transferred from one computer-readable storage medium to another.

[0077] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0078] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0079] 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 variations or substitutions within the technical scope disclosed in the present invention, and these should all be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A dual-frequency ADCP adaptive current measurement method, characterized in that, include: Real-time acquisition of environmental characteristic parameters of the measured water area, including water depth data, high and low frequency echo intensity of multiple depth units, and high and low frequency signal-to-noise ratio of multiple depth units; Based on a preset depth-first rule, the corresponding initial working mode is selected according to the environmental characteristic parameters; wherein, the initial working mode is preset with specified high and low frequency bands and specified flow measurement modes. The composite quality index is calculated based on the high and low frequency echo intensities and the high and low frequency signal-to-noise ratios, including: mapping the high frequency signal-to-noise ratio of multiple depth cells to a first normalized value using a first normalization function; mapping the high frequency echo intensities of multiple depth cells to a second normalized value using a second normalization function, and weighting the first and second normalized values ​​to obtain a high frequency composite quality index; mapping the low frequency signal-to-noise ratio of multiple depth cells to a third normalized value using a first normalization function; and mapping the low frequency echo intensities of multiple depth cells to a fourth normalized value using a second normalization function, and weighting the third and fourth normalized values ​​to obtain a low frequency composite quality index. The high and low frequency bands of the initial working mode are verified based on the composite quality index, and the frequency band is switched to the target frequency band according to the verification result, including: when the value of the high frequency composite quality index minus the low frequency composite quality index is greater than a preset threshold, the high frequency band is switched to the target frequency band; when the value of the low frequency composite quality index minus the high frequency composite quality index is greater than the preset threshold, the low frequency band is switched to the target frequency band. Based on the signal-to-noise ratio of multiple deep cells in the target frequency band, quality detection is performed on the target frequency band, and the flow measurement mode is locked or switched according to the quality detection results to obtain the target flow measurement mode; The flow in the measured water area is measured according to the target frequency band and the target flow measurement mode to obtain the flow measurement results.

2. The dual-frequency ADCP adaptive current measurement method according to claim 1, characterized in that, The process of performing quality detection on the target frequency band based on the signal-to-noise ratio of multiple deep cells in the target frequency band, and locking or switching the flow measurement mode according to the quality detection results to obtain the target flow measurement mode includes: The number of depth cells with a signal-to-noise ratio greater than or equal to a preset available threshold in the target frequency band among all effective depth cells is counted, and the proportion of the depth cells to the total number of all effective depth cells is calculated. If the ratio is greater than or equal to a preset ratio threshold, then the pulse coherence mode is selected as the target flow measurement mode for the target frequency band; if the ratio is less than the preset ratio threshold, then the broadband mode is selected as the target flow measurement mode.

3. The dual-frequency ADCP adaptive current measurement method according to claim 2, characterized in that, Also includes: When the absolute value of the high-frequency composite quality index minus the low-frequency composite quality index is less than or equal to a preset threshold, and the high-frequency signal-to-noise ratio is less than the available threshold and the low-frequency signal-to-noise ratio is less than the available threshold, the target frequency band and the target flow measurement mode are determined based on the dual-frequency fusion strategy.

4. The dual-frequency ADCP adaptive current measurement method according to claim 3, characterized in that, The determination of the target frequency band and the target current measurement mode based on the dual-frequency fusion strategy includes: The weighting coefficient is determined based on the proportion of the effective range of high frequency in the total water depth, and the entire measurement water area is divided into an upper layer region and a lower layer region based on the weighting coefficient. The target frequency band corresponding to the upper region is switched to a high frequency band, the target frequency band corresponding to the lower region is switched to a low frequency band, and the flow measurement mode corresponding to the broadband mode is synchronously determined as the target flow measurement mode of the upper region and the target flow measurement mode of the lower region.

5. The dual-frequency ADCP adaptive current measurement method according to claim 1, characterized in that, The environmental characteristic parameters also include flow velocity; when the water depth data is less than or equal to 6m and the flow velocity is greater than or equal to 0.4m / s, the target frequency band of the initial working mode is the high frequency band by default, and the target flow measurement mode is the broadband mode.

6. A dual-frequency ADCP adaptive flow measurement system, characterized in that, include: The acquisition unit is used to acquire environmental characteristic parameters of the measured water area in real time. The environmental characteristic parameters include water depth data, high and low frequency echo intensity of multiple depth units, and high and low frequency signal-to-noise ratio of multiple depth units. The mode selection unit is used to select the corresponding initial working mode according to the environmental characteristic parameters based on the preset depth priority rule; wherein, the initial working mode is preset with specified high and low frequency bands and specified flow measurement mode. A frequency band verification unit is used to calculate a composite quality index based on the high and low frequency echo intensities and the high and low frequency signal-to-noise ratios, including: mapping the high frequency signal-to-noise ratios of multiple depth cells to a first normalized value using a first normalization function; mapping the high frequency echo intensities of multiple depth cells to a second normalized value using a second normalization function, and weighting the first normalized value and the second normalized value to obtain a high frequency composite quality index; mapping the low frequency signal-to-noise ratios of multiple depth cells to a third normalized value using a first normalization function; and mapping the low frequency echo intensities of multiple depth cells to a third normalized value using a second normalization function. The second normalization function is mapped to a fourth normalization value, and the third normalization value and the fourth normalization value are weighted and combined to obtain a low-frequency composite quality index. The frequency band verification unit is also used to verify the high and low frequency bands of the initial working mode based on the composite quality index, and switch to the target frequency band according to the verification result, including: when the value of the high-frequency composite quality index minus the low-frequency composite quality index is greater than a preset threshold, the high-frequency band is switched to the target frequency band; when the value of the low-frequency composite quality index minus the high-frequency composite quality index is greater than the preset threshold, the low-frequency band is switched to the target frequency band. The quality detection unit performs quality detection on the target frequency band based on the signal-to-noise ratio of multiple deep units in the target frequency band, and locks or switches the flow measurement mode according to the quality detection results to obtain the target flow measurement mode; The flow measurement main control unit measures the flow in the measured water area according to the target frequency band and the target flow measurement mode, and outputs the flow measurement results.

7. An electronic device, characterized in that, include: A processor and a memory, wherein the memory stores instructions that are loaded and executed by the processor to implement the dual-frequency ADCP adaptive flow measurement method as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the dual-frequency ADCP adaptive current measurement method as described in any one of claims 1 to 5.

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