A tide level monitoring device, method and system based on a triple-lens millimeter-wave radar

Abstract

A tide level monitoring device, method and system based on a three-eye lens millimeter wave radar, belonging to the technical field of sea surface tide level monitoring, to solve the problem that the existing single millimeter wave radar for monitoring tide level often cannot achieve high precision, and at the same time, it cannot overcome the interference of sea clutter to the monitoring data. The tide level monitoring device of the present invention includes four parts: a fixed bracket, a three-eye lens millimeter wave radar monitoring system, a power supply system and a remote data display system; among them, the three-eye lens millimeter wave radar monitoring system includes a millimeter wave radar monitoring platform, an environmental monitoring platform and a communication module; the millimeter wave radar monitoring platform includes a housing, a 77GHz millimeter wave radar, a millimeter wave radar lens switching device, a pitch rotation device and a data processing controller; the environmental monitoring platform includes an anemometer and a wind vane; the millimeter wave radar lens switching device is controlled to switch the millimeter wave lens below the 77GHz millimeter wave radar according to the magnitude of the currently collected wind speed, so as to achieve high-precision tide level monitoring.

Description

Technical Field

[0001] The invention patent belongs to the technical field of sea level monitoring, and particularly relates to a tide level monitoring device, method and system based on a three-eye lens millimeter wave radar. Background Art

[0002] Tide level monitoring has important application values in many ocean-related fields. For example, tides are very crucial for the time and safety of ships entering and leaving ports. If leaving the port at low tide, there may be risks of water shortage and stranding, while returning to the port at high tide may face the danger of being impacted by sea waves. By monitoring the changes in tide levels, the occurrence time and scale of marine natural disasters such as tsunamis and storm surges can be predicted, providing a scientific basis for disaster warning and mitigation. Long-term series of tide level change data can be obtained, providing necessary data support for fields such as fisheries and marine energy. Traditional fixed tide gauges use a vertically downward measurement method, which is easily interfered by factors such as oblique waves and reefs, and is also affected by environmental factors such as rain, strong winds, and sea fog, resulting in measurement errors. The float-type tide gauge is greatly affected by seawater temperature, affecting measurement accuracy. The changes in tide levels under different sea surface environmental conditions are significant. If a single millimeter wave radar is used to monitor the tide level, high accuracy is often not achievable. At the same time, the echo data of the monitored tide level signal is greatly interfered by sea clutter. Summary of the Invention

[0003] The technical problems to be solved by the present invention are:

[0004] Existing methods for monitoring tide levels using a single millimeter wave radar often cannot achieve high accuracy. At the same time, it is impossible to overcome the interference of sea clutter on the monitored data.

[0005] The technical solutions adopted by the present invention to solve the above technical problems are:

[0006] The present invention provides a tide level monitoring device based on a three-eye lens millimeter wave radar. The tide level monitoring device includes four parts: a fixed bracket, a three-eye lens millimeter wave radar monitoring system, a power supply system, and a remote data display system.

[0007] The three-eye lens millimeter wave radar monitoring system includes a millimeter wave radar monitoring platform, an environmental monitoring platform, and a communication module. The millimeter wave radar monitoring platform includes a housing, a 77 GHz millimeter wave radar, a millimeter wave radar lens switching device, a pitch rotation device, and a data processing controller.

[0008] There is a region made of wave-transparent material below the housing, and the inside of the housing is a 77 GHz millimeter wave radar and a millimeter wave radar lens switching device. The millimeter wave radar lens switching device is installed below the 77 GHz millimeter wave radar. The environmental monitoring platform includes an anemometer and a wind vane.

[0009] The fixed bracket includes a base and a link assembly; the base is installed on the coastal water level corresponding to the tidal level to be monitored, the base is rotatably connected to one end of the link assembly, and the other ends of the link assembly are respectively connected to the millimeter-wave radar monitoring platform and the environmental monitoring platform. The position of the three-eye lens millimeter-wave radar monitoring system extending out of the sea level can be adjusted through the fixed bracket;

[0010] The three-eye lens millimeter-wave radar monitoring system is used to periodically pitch-monitor the tidal level information of the sea level through the radar, and is also used to monitor the wind speed and wind direction of the tidal level. The anemometer and wind vane of the environmental monitoring platform measure the wind speed and wind direction information, and transmit the wind speed and wind direction data to the data processing controller. According to the magnitude of the current wind speed, the data processing controller controls the millimeter-wave radar lens switching device to switch the millimeter-wave lens below the 77GHz millimeter-wave radar. In the case of small waves and wind speed, narrow-beam millimeter-wave monitoring is adopted. In the case of large waves and wind speed, wide-beam millimeter-wave monitoring is adopted; the tidal level data monitored by the 77GHz millimeter-wave radar is transmitted to the data processing controller, and the data processing controller optimizes the tidal level data and transmits it to the remote data display system through the communication module;

[0011] The power supply system is used to supply power to the data processing controller, data storage module, communication module, millimeter-wave radar lens switching device, pitch rotation device and 77GHz millimeter-wave radar;

[0012] The remote data display system is used to display the monitoring data of the three-eye lens millimeter-wave radar monitoring system, and display an alarm message when the tidal level height is higher than the threshold.

[0013] Further, the millimeter-wave radar lens switching device includes an electric servo motor at the center, a short-focus focusing lens and a long-focus focusing lens at both ends. The two lenses are respectively connected to the servo motor through short rods. According to the wind speed, the data processing controller controls the electric servo motor to rotate to switch the lens below the 77GHz millimeter-wave radar.

[0014] Further, the power supply system is a solar power supply system. When there is sunlight, it supplies power to the three-eye lens millimeter-wave radar tidal level monitoring system through solar energy. When the electric energy generated by the solar panel exceeds the current demand, the excess electric energy is stored in the storage battery through the power management module and continues to supply power at night, on cloudy days or other low-light conditions.

[0015] The present invention provides a tidal level monitoring method based on a three-eye lens millimeter-wave radar, and the method includes the following steps:

[0016] Step 1. Install the three-eye lens millimeter-wave radar monitoring system device on the shore of the sea area to be monitored through a fixed bracket. Adjust the initial positions of the millimeter-wave radar monitoring platform and the environmental monitoring platform to a horizontal state, so that the 77GHz millimeter-wave radar is facing the sea level directly. Measure the wind speed and wind direction information within one working cycle through an anemometer and a wind vane.

[0017] Step 2. After the data processing controller receives the wind direction and wind speed information data, the data processing controller determines that the current wind speed is within the preset wind speed threshold range. According to the threshold range where the wind speed is located, control the electric servo to rotate the short-focus focusing lens or the long-focus focusing lens under the 77GHz millimeter-wave radar, or directly measure with the 77GHz millimeter-wave radar without using a lens.

[0018] Step 3. Conduct tide level monitoring on the monitored sea area. The data processing controller controls the pitch rotation device to rotate, and the 77GHz millimeter-wave radar periodically scans the sea area to be monitored to obtain radar monitoring data. Suppress the sea clutter in the data through an adaptive clutter suppression algorithm, and remove the outliers in the monitoring data, and then perform data fusion through a centralized optimal weighted fusion algorithm.

[0019] Step 4. Upload the tide level, wind speed, wind direction and time data to the remote data display system through the communication module, draw the tide level change curve, and when the tide level is higher than the threshold or the wind speed is greater than the threshold, display an alarm message through the display system.

[0020] Further, step 2 specifically includes: after the data processing controller receives the wind direction and wind speed information data, the data processing controller analyzes the wind speed. If the wind speed is in a small wind force state less than 3m / s, control the electric servo to rotate the short-focus focusing lens under the 77GHz millimeter-wave radar. The short-focus focusing lens converges the beam to achieve high-precision monitoring of the sea surface tide level by the narrow-beam millimeter-wave radar. If the wind speed is in a medium wind force state between 3m / s and 6m / s, control the electric servo to rotate the long-focus focusing lens under the 77GHz millimeter-wave radar. The long-focus focusing lens converges the beam to achieve monitoring of the sea surface tide level by the medium-beam millimeter-wave radar. If the wind speed is in a strong wind force state greater than 6m / s, do not use a lens, and use the 77GHz millimeter-wave radar to monitor the sea surface tide level.

[0021] Further, the millimeter-wave radar in step 3 uses a 77GHz frequency-modulated continuous-wave millimeter-wave radar, and the transmission frequency of the radar is:

[0022]

[0023] where t is time, f0 is the working center frequency of the transmitted signal, μ is the modulation slope, B is the modulation bandwidth, and T is the modulation period.

[0024] The receiving frequency of the radar is:

[0025] f Re (t) = f0 + μ(t - τ) + f d (2)

[0026] Where, f d is the Doppler frequency, τ is the propagation time of the signal in the air. Assuming the distance of the millimeter-wave radar from the sea level is L and the speed of light is c, then:

[0027]

[0028] Regarding the up and down surging of the sea surface as a motion process, since the sea wave surging is a reciprocating up and down motion, it can be balanced and offset with each other in each set of a large amount of data. The Doppler frequency f d can be ignored. Then the echo signal model is expressed as:

[0029]

[0030] Where, K is a scaling factor constant, A is the signal amplitude, and φ0 is the initial phase of the signal;

[0031] The phase of the echo signal is expressed as:

[0032]

[0033] The phase of the radar beat signal is expressed as:

[0034] p m (t) = p Tr (t) - p Re (t) = 2πf0τ + 2πμτt - πμτ 2 (6)

[0035] Based on the phase p m (t) of the radar beat signal, solving for the frequency of the radar beat signal is:

[0036]

[0037] It is obtained that:

[0038]

[0039] Furthermore, suppressing the sea clutter in the data by the adaptive clutter suppression algorithm described in step three is specifically:

[0040] Discretizing the echo signal model y R (t). Suppose the observation equation of the millimeter-wave radar for the tide level at angle i is:

[0041] Y i Y(k)=X(k)+C i Y(k)+N i Y(k) i=1,2,…,I (9)

[0042] Where Y i Y(k) is the observed signal of the target at time k, X(k) is the target signal at time k, C i C(k) is the clutter signal, N i N(k) is the Gaussian white noise signal, and I is the number of observation angles;

[0043] The echo signals of different distance units and their adjacent range gates are {y i,j Y(k)∣i=1,2,…,I;j=1,2,…,J}, where J is the number of range gates, representing the echo signals at different distance positions measured by the radar; the echo data of different range gates satisfy independent and identically distributed, then based on all the sea clutter sub-signals C i C(k) to form the covariance matrix R C is:

[0044]

[0045] Where p is the filter order, r C r(·) is the clutter autocorrelation function, is the conjugate complex number of the clutter autocorrelation function, r C The expression of r(·) is:

[0046]

[0047] Where m represents the delay amount of the signal when calculating the autocorrelation;

[0048] Perform eigenvalue decomposition on the covariance matrix R C to obtain the eigenvalues λ i and the eigenvectors W i corresponding to the eigenvalues λ i :

[0049] R C W i =λ i W i (12)

[0050] The minimum value λ i of the eigenvalues λ of the sea clutter covariance matrix min The corresponding eigenvector is the optimal weighting coefficient of the adaptive clutter suppression algorithm, denoted as W o , and the echo signal after suppressing the sea clutter is:

[0051] Z i Z(k)=W0Yi (k) (13).

[0052] Further, the removal of outliers in the monitoring data in step three is specifically as follows:

[0053] For the millimeter-wave radar ranging data at each angle, calculate the vertical distance d from the millimeter-wave radar monitoring platform to the sea surface:

[0054]

[0055] where α is the angle between the millimeter-wave radar antenna plane and the horizontal plane;

[0056] Obtain a set of tide level height data, and then continue to monitor cyclically; remove outliers in the tide level data through the Grubbs test method, that is, first calculate the average value as:

[0057]

[0058] where n is the number of data measured at each angle, and the calculated standard deviation S is:

[0059]

[0060] Calculate the G value as:

[0061]

[0062] Refer to the Grubbs criterion discrimination coefficient table to find the coefficient G corresponding to the sample size n and confidence level q of a set of tide level data 表 , if G 表 > G 计算 , then it is determined as abnormal data and removed, otherwise it is retained.

[0063] Further, the data fusion through the centralized optimal weighted fusion algorithm in step three is specifically as follows: Use the millimeter-wave radar to measure a set of tide level change data at each angle, and calculate the mean value and standard deviation for each set of data; Assume that the observation equation of the millimeter-wave radar for the tide level at the i-th angle at time k after suppressing sea clutter is:

[0064] Z i (k) = X(k) + N i (k) i = 1, 2, …, I (18)

[0065] The radar observation noise simultaneously satisfies:

[0066]

[0067] where E represents expectation and D represents variance, is the variance value at each moment under the i-th angle;

[0068] The measurement noises of the millimeter-wave radar at each angle are uncorrelated, that is:

[0069]

[0070] Different weights are assigned to the radars at each angle to obtain a virtual measurement value;

[0071]

[0072] where α i is the weighting coefficient for the millimeter-wave radar to measure the tide level data at the i-th angle. To ensure the unbiasedness of the estimation, it satisfies:

[0073]

[0074] That is, when then is an unbiased estimate of X;

[0075] The estimated mean square error is established, and the expression is:

[0076]

[0077] Use the Lagrange conditional extreme value to solve the weighting coefficients of the radars at each angle when the estimated variance is minimized, with the help of the auxiliary function:

[0078]

[0079] where Λ is the constraint weight in the Lagrange multiplier; thus, a system of equations is established:

[0080]

[0081] Solve the system of equations to obtain:

[0082]

[0083] At this time, the estimated variance reaches the minimum value of:

[0084]

[0085] The present invention provides a tide level monitoring system based on a three-lens millimeter-wave radar. The system has program modules corresponding to the steps of the method described in any one of the above technical solutions, and executes the steps in the above-mentioned tide level monitoring method based on a three-lens millimeter-wave radar when running.

[0086] Compared with the prior art, the beneficial effects of the present invention are:

[0087] The present invention relates to a tide level monitoring device, method and system based on a three-lens millimeter wave radar. It adopts a method of collaborative work between a 77GHz millimeter wave radar and a millimeter wave lens. Wind speed and wind direction information are collected by a wind speed and wind direction sensor, and the lens below the millimeter wave radar is controlled to switch, so as to use beams with different widths for tide level monitoring in different sea wave conditions. This not only weakens the influence of environmental factors on the monitoring results, but also overcomes the monitoring errors of a single millimeter wave radar in different sea wave conditions. Finally, the tide level height is comprehensively monitored by rotating the pitch axis to obtain more accurate tide level change data. The present invention performs sea clutter suppression processing on each group of original data to reduce the interference of sea clutter on the monitoring results, then removes outliers, and finally obtains tide level data through a centralized optimal weighted fusion algorithm to obtain more accurate tide level data, which is uploaded to a remote data display system for display through a communication module, and an alarm message is sent after exceeding the set threshold.

[0088] The present invention has a high level of intelligence and is powered by solar energy, which conforms to the development concept of green environmental protection. Brief Description of the Drawings

[0089] Figure 1 It is a schematic structural diagram of a tide level monitoring device based on a three-lens millimeter wave radar in an embodiment of the present invention;

[0090] Figure 2 It is a schematic diagram of a millimeter wave radar lens switching device in an embodiment of the present invention;

[0091] Figure 3 It is a working flow chart of a tide level monitoring system based on a three-lens millimeter wave radar in an embodiment of the present invention;

[0092] Figure 4 It is a schematic diagram of millimeter wave radar monitoring in an embodiment of the present invention;

[0093] Figure 5 It is a schematic diagram of a remote data center in an embodiment of the present invention;

[0094] Figure 6 It is an upper computer interface diagram of a remote data center in an embodiment of the present invention.

[0095] Description of the Reference Numerals:

[0096] 1 - Bracket, 2 - Three - lens millimeter - wave radar monitoring system, 3 - Power supply system, 4 - Remote data display system, 11 - Base, 12 - Right - angle connecting rod, 13 - Support rod, 14 - Horizontal tabletop, 21 - Millimeter - wave radar monitoring platform, 22 - Environment monitoring platform, 23 - Communication module, 41 - Computer host, 42 - Monitor, 211 - Housing, 212 - 77GHz millimeter - wave radar, 213 - Millimeter - wave radar lens switching device, 214 - Pitch - rotation device, 215 - Data processing controller, 221 - Anemometer, 222 - Wind vane, 2131 - Electric servo, 2132 - Short - focal - length focusing lens, 2133 - Long - focal - length focusing lens. Detailed implementation manners

[0097] In order to enable those skilled in the art to better understand the solution of the present invention, the exemplary embodiments or examples of the present invention will be described below in conjunction with the accompanying drawings. Obviously, the described embodiments or examples are only part of the embodiments or examples of the present invention, rather than all of them. All other embodiments or examples obtained by those of ordinary skill in the art based on the embodiments or examples of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0098] In the description of the present invention, it should be noted that the terms such as "upper", "lower", "front", "rear", "left", "right" and other terms indicating directions in each embodiment are only used to simplify the description of the positional relationship based on the drawings of the specification, and do not represent that the indicated elements and devices must operate according to the specific directions and limited operations, methods, and structures described in the specification. Such directional terms do not constitute a limitation to the present invention.

[0099] In the description of the present invention, it should be noted that the terms "first", "second", "third" mentioned in the embodiments of the present invention are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", "third" may explicitly or implicitly include one or more of such features.

[0100] To make the above - mentioned objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given in conjunction with the accompanying drawings.

[0101] Combined with Figure 1 and Figure 2 As shown, the present invention provides a tide level monitoring device based on a three - lens millimeter - wave radar. The tide level monitoring device includes four parts: a fixed bracket 1, a three - lens millimeter - wave radar monitoring system 2, a power supply system 3, and a remote data display system 4.

[0102] The three - lens millimeter - wave radar monitoring system 2 includes a millimeter - wave radar monitoring platform 21, an environmental monitoring platform 22, and a communication module 23; the millimeter - wave radar monitoring platform 21 includes a housing 211, a 77GHz millimeter - wave radar 212, a millimeter - wave radar lens switching device 213, a pitch - rotation device 214, and a data - processing controller 215;

[0103] There is a region made of wave - transmitting material below the housing 211, and inside the housing 211 are the 77GHz millimeter - wave radar 212 and the millimeter - wave radar lens switching device 213; the millimeter - wave radar lens switching device 213 is installed below the 77GHz millimeter - wave radar 212. The environmental monitoring platform 22 includes an anemometer 221 and a wind vane 222;

[0104] The fixed bracket 1 includes a base 11 and a connecting - rod assembly; the base 11 is installed on the coastal water level corresponding to the tide level to be monitored, the base 11 is rotatably connected to one end of the connecting - rod assembly, and the other ends of the connecting - rod assembly are respectively connected to the millimeter - wave radar monitoring platform 21 and the environmental monitoring platform 22. The position of the three - lens millimeter - wave radar monitoring system 2 extending out of the sea level can be adjusted through the fixed bracket 1;

[0105] The three - lens millimeter - wave radar monitoring system 2 is used to periodically pitch - monitor the tide - level information of the sea level through the radar, and is also used to monitor the wind speed and wind direction of the tide level. It controls the anemometer 221 and the wind vane 222 of the environmental monitoring platform 22 to measure the wind - speed and wind - direction information, and transmits the wind - speed and wind - direction data to the data - processing controller 215. The data - processing controller 215 is integrated at the uppermost end of the millimeter - wave radar monitoring platform 21. According to the magnitude of the current wind speed, it controls the millimeter - wave radar lens switching device 213 to switch the millimeter - wave lens below the 77GHz millimeter - wave radar 212, so as to achieve narrow - beam millimeter - wave monitoring in the case of small waves and wind speed, and wide - beam millimeter - wave monitoring in the case of large waves and wind speed; the tide - level data monitored by the 77GHz millimeter - wave radar 212 is transmitted to the data - processing controller 215, and the data - processing controller 215 optimally processes the tide - level data. The communication module 23 is a 4G wireless communication module, and the communication module 23 uploads the monitoring data to the cloud server. The remote data - display system 4 reads the monitoring data of the three - lens millimeter - wave radar monitoring system in the cloud server and displays the information;

[0106] The power - supply system 3 is used to supply power to the data - processing controller 215, the data - storage module, the communication module 23, the millimeter - wave radar lens switching device 213, the pitch - rotation device 214, and the 77GHz millimeter - wave radar 212;

[0107] As Figure 5As shown, the remote data display system 4 includes a computer host 41 and a display 42. The remote data display system 4 reads the monitoring data of the three-eye lens millimeter-wave radar monitoring system in the cloud server and displays information. At the same time, it stores the information of the tide level height, wind speed, and wind direction in the local space. The computer host 41 accesses the cloud server through an optical fiber to receive real-time data information, displays the wind speed magnitude, wind direction information, the current tide level height, and the change curve of the tide level height in the recent two hours. When the tide level height is higher than the threshold, an alarm message is displayed.

[0108] In this embodiment, the beam width of the 77GHz millimeter-wave radar 212 is ±15° and the range is 30 meters. It has a relatively wide beam width and is not affected by light, fog, or rain, solving the problem that ultrasonic sensors and optical sensors cannot penetrate sea fog and rain. It is suitable for monitoring the tide level height when the sea waves and wind are large, can more accurately locate the target distance, and enhance the anti-interference ability of the tide level monitoring system. In the case of small sea waves and wind, a millimeter-wave lens is placed in front of the millimeter-wave radar antenna to achieve narrow-beam millimeter-wave monitoring and improve the measurement resolution.

[0109] Preferably, the link assembly of the fixed bracket 1 includes a right-angle connecting rod 12, a support rod 13, and a horizontal table 14. The base 11 of the bracket is installed on the coastal water surface corresponding to the tide level to be monitored using expansion anchor bolts. One end of the base 11 is connected to one end of the right-angle connecting rod 12. The other end of the right-angle connecting rod 12 extends out of the water surface. A support rod 13 is installed at the bending part of the right-angle connecting rod 12 to form a triangular bracket to enhance the stability of the fixed bracket. The inside of the right-angle connecting rod 12 is a hollow structure for accommodating signal transmission lines and power lines. The horizontal table 14 is installed above the end of the right-angle connecting rod 12 that extends out of the water surface. The anemometer 221, wind vane 222, and communication module 23 are all installed on the horizontal table 14. The millimeter-wave radar monitoring platform 21 is installed below the end of the right-angle connecting rod 12 that extends out of the water surface. The fixed bracket 1 installs the three-eye lens millimeter-wave radar monitoring system 2 on the shore of the sea area to be monitored and adjusts the three-eye lens millimeter-wave radar monitoring system 2 to extend 2 meters out of the water surface.

[0110] Preferably, as Figure 2 shown, the millimeter-wave radar lens switching device 213 includes an electric servo 2131 at the center and short-focus focusing lenses 2132 and long-focus focusing lenses 2133 at both ends. The two lenses are respectively connected to the servo through short rods. According to the wind speed magnitude, the data processing controller 215 outputs PWM signals of different frequencies to control the rotation of the electric servo 2131 and switch the lens below the 77GHz millimeter-wave radar 212 to different lenses.

[0111] Preferably, the data processing controller 215 includes a data processing unit and a central control unit, which work together. It is connected to an anemometer and an eight-direction wind vane through an RS485 interface, communicates through the Modbus-RTU protocol, receives data from the anemometer 221 and the wind vane, obtains real-time wind speed and wind direction information, sets a wind speed threshold, determines the wind speed threshold space where the current wind speed is located, and controls the rotation of the electric servo 2131 to switch the lens under the millimeter-wave radar; controls the pitching and rotating device 214 to rotate through a preset program, periodically scans the sea area to be monitored. When the pitching and rotating device 214 rotates, the antenna surface of the 77GHz millimeter-wave radar 212 stays at 0°, 30°, and 60° with the horizontal plane. One data is obtained at each angle, and each working cycle is repeated 10 times to obtain a set of data. The working interval is 20 minutes, and this cycle repeats periodically.

[0112] Preferably, the power supply system 3 is a solar power supply system. When there is sunlight, it powers the three-lens millimeter-wave radar tide level monitoring system through solar energy. When the electric energy generated by the solar panel exceeds the current demand, the excess electric energy is stored in the battery through the power management module and continues to supply power at night, on cloudy days, or under other low-light conditions.

[0113] The present invention also provides a tide level monitoring method based on a three-lens millimeter-wave radar, as Figure 3 shown, including the following steps:

[0114] Step 1: Install the above three-lens millimeter-wave radar monitoring system 2 device on the shore of the sea area to be monitored through the fixed bracket 1. Adjust the initial positions of the millimeter-wave radar monitoring platform 21 and the environmental monitoring platform 22 to a horizontal state, make the 77GHz millimeter-wave radar 212 face the sea level directly, and obtain the wind speed and wind direction information within one working cycle through the anemometer 221 and the wind vane 222.

[0115] Step 2: After the data processing controller 215 receives the wind direction and wind speed information data, the data processing controller 215 determines that the current wind speed is within the preset wind speed threshold range, controls the electric servo 2131 according to the threshold range where the wind speed is located, rotates the short-focus focusing lens 2132 or the long-focus focusing lens 2133 to the lower part of the 77GHz millimeter-wave radar 212, or directly measures using the 77GHz millimeter-wave radar 212 without using a lens.

[0116] Step 3: Conduct tide level monitoring on the sea area to be monitored. The data processing controller 215 controls the pitching and rotating device 214 to rotate, and the 77GHz millimeter-wave radar 212 periodically scans the sea area to be monitored to obtain radar monitoring data. Suppress the sea clutter in the data through the adaptive clutter suppression algorithm, remove the outliers in the monitoring data, and then perform data fusion through the centralized optimal weighted fusion algorithm.

[0117] Step 4: Upload the tide level, wind speed, wind direction, and time data to the cloud server through the communication module 23. The remote data display system 4 reads the data in the cloud server, displays the information through the display 42, draws the tide level change curve, and saves the data to the database. When the tide level is higher than the threshold or the wind speed is greater than the threshold, an alarm message is displayed through the display system.

[0118] Preferably, in step 1, before the three-eye lens millimeter wave radar monitoring system officially starts working, first collect the wind speed and wind direction information within a working cycle time, which is used to adjust the selection of the millimeter wave lens in the first working cycle. Each working cycle is 20 minutes, and the wind speed and wind direction information collected in each subsequent working cycle will be used as the reference data for the lens selection in the next cycle.

[0119] Preferably, step 2 specifically includes: after the data processing controller 215 receives the wind direction and wind speed information data of the previous working cycle, the data processing controller 215 analyzes the wind speed. If the wind speed is in the small wind force state of less than 3 m / s, control the electric servo 2131 to rotate the short focal length focusing lens 2132 below the 77 GHz millimeter wave radar 212. The short focal length focusing lens 2132 converges the beam to achieve high-precision monitoring of the sea surface tide level by the narrow beam millimeter wave radar; if the wind speed is in the medium wind force state between 3 m / s and 6 m / s, control the electric servo 2131 to rotate the long focal length focusing lens 2133 below the 77 GHz millimeter wave radar 212. The long focal length focusing lens 2133 converges the beam to achieve monitoring of the sea surface tide level by the medium beam millimeter wave radar; if the wind speed is in the strong wind force state of greater than 6 m / s, no lens is used, and the 77 GHz millimeter wave radar 212 is used to monitor the sea surface tide level.

[0120] Preferably, the millimeter wave radar described in step 3 is a 77 GHz frequency modulated continuous wave (FMCW) millimeter wave radar. The FMCW millimeter wave radar monitors the tide level height by calculating the delay between the radar transmitted signal and the echo signal. The transmission frequency of the radar is:

[0121]

[0122] where t is time, f0 is the working center frequency of the transmitted signal, μ is the modulation slope, B is the modulation bandwidth, and T is the modulation period;

[0123] The receiving frequency of the radar is:

[0124] f Re (t) = f0 + μ(t - τ) + f d (2)

[0125] where fd where \(f_d\) is the Doppler frequency, \(\tau\) is the propagation time of the signal in air. Assuming the distance of the millimeter-wave radar from the sea level is \(L\) and the speed of light is \(c\), then:

[0126]

[0127] Regarding the up-and-down movement of the sea surface as a motion process, since the wave surging is a reciprocating up-and-down motion, it can be mutually balanced and canceled out in each set of a large amount of data. The Doppler frequency \(f_d\) d can be neglected, and the echo signal model can be expressed as:

[0128]

[0129] where \(K\) is a scaling factor constant, \(A\) is the signal amplitude, and \(\varphi_0\) is the initial phase of the signal;

[0130] The phase of the echo signal can be expressed as:

[0131]

[0132] The phase of the radar difference frequency signal can be expressed as:

[0133] p m p(t)=p Tr (t)-p Re (t)=2\pi f_0\tau + 2\pi\mu\tau t-\pi\mu\tau 2 (6)

[0134] Differentiating the phase \(p(t)\) of the radar difference frequency signal with respect to time to obtain the instantaneous angular frequency, and then dividing by \(2\pi\) to obtain the instantaneous frequency, the frequency of the radar difference frequency signal can be expressed as: m (t) with respect to time to obtain the instantaneous angular frequency, and then dividing by \(2\pi\) to obtain the instantaneous frequency, then the frequency of the radar difference frequency signal can be expressed as:

[0135]

[0136] Obtain:

[0137]

[0138] Preferably, suppressing the sea clutter in the data through the adaptive clutter suppression algorithm can adjust the filter parameters according to the statistical characteristics of the clutter, which is suitable for suppressing dynamic sea clutter; discretizing the echo signal \(y(t)\), and assuming that the observation equation of the millimeter-wave radar for the tide level at angle \(i\) is: R (t) is discretized. Assuming that the observation equation of the millimeter-wave radar for the tide level at angle \(i\) is:

[0139] Y i (k)=X(k)+C i (k)+N i (k) \(i = 1,2,\cdots,I\) (9)

[0140] where \(Y\)i The observation signal of the target at time k is \(Z(k)\), and \(X\) i The target signal at time k is \(X(k)\), and \(C\) i (k) is the clutter signal, \(N(k)\) is the Gaussian white noise signal, and \(I\) is the number of observation angles;

[0141] The tide level monitoring radar works for a long time to obtain sample data at different tide levels and angles, and the echo signals \(\{y\) i,j (k)|i = 1, 2, …, I; j = 1, 2, …, J} can be obtained, where \(J\) is the number of range gates; it represents the echo signals at different range positions measured by the radar; the echo data of different range gates satisfy independent and identically distributed, so based on all the sea clutter sub-signals \(C\) i (k), the covariance matrix \(R\) C is:

[0142]

[0143] where \(p\) is the filter order, and \(r\) C (·) is the clutter autocorrelation function, is the conjugate complex number of the clutter autocorrelation function, and \(r\) C (·) is expressed as:

[0144]

[0145] where \(m\) represents the delay amount of the signal when calculating the autocorrelation;

[0146] Perform eigenvalue decomposition on the covariance matrix \(R\) C to obtain the eigenvalues \(\lambda\) i and the eigenvectors \(W\) i corresponding to the eigenvalues \(\lambda\) i :

[0147] \(R\) C \(W\) i =\(\lambda\) i \(W\) i (12)

[0148] The minimum value \(\lambda\) i of the eigenvalues of the sea clutter covariance matrix and the eigenvector corresponding to \(\lambda\) min are the optimal weighting coefficients of the adaptive clutter suppression algorithm, denoted as \(W\) o , and the echo signal after suppressing the sea clutter is:

[0149] \(Z\) i (k) = \(W_0Y\) i (k) (13).

[0150] The weighting coefficients of the filter can be adjusted according to the statistical characteristics of sea clutter to suppress sea clutter in the echo signal and obtain an ideal output signal.

[0151] Preferably, removing the outliers in the monitoring data in step 3 specifically includes: the control system controls the pitch rotation device 214 to rotate. The stepping motor is a control element that converts a pulse signal into an angular displacement or a linear displacement. The specific method for controlling the pitch rotation device 214 to rotate is: after determining the lens used by the monitoring platform in the current measurement period, through a preset program, control the pitch rotation device 214 to rotate, so that the antenna surface of the 77 GHz millimeter-wave radar 212 stays at 0°, 30°, and 60° with the horizontal plane, and obtain a radar ranging data at each angle. As Figure 4 shown, calculate the vertical distance d from the millimeter-wave radar monitoring platform to the sea surface through the Pythagorean theorem of a triangle:

[0152]

[0153] where α is the angle between the antenna surface of the millimeter-wave radar and the horizontal plane;

[0154] Obtain a set of tide level data, and then continue to rotate in a loop. The loop period is 20 minutes;

[0155] Outliers will have a greater impact on the real data. There are mainly three factors that cause outliers: the first is that sea reefs are within the radar detection range, causing long-term detection errors; the second is that ships or other objects pass through the radar detection range, causing short-term fluctuating detection errors; the third is being interfered by electromagnetic signals, making the echo received by the millimeter-wave radar inaccurate and causing detection errors. Remove the outliers in a set of tide level data through the Grubbs test method. The specific method is to first calculate the average value of a set of tide level data

[0156]

[0157] where n is the amount of data measured at each angle, and calculate the standard deviation S as:

[0158]

[0159] Calculate the G value:

[0160]

[0161] Refer to the Grubbs criterion discrimination coefficient table to find the coefficient G corresponding to the sample size n and confidence level q of a set of tide level data 表 If G 表 > G 计算 , then it is determined as abnormal data and removed, otherwise it is retained.

[0162] Preferably, in step three, the data fusion is performed by a centralized optimal weighted fusion algorithm, specifically: regarding the change in the sea level tide height as a dynamic motion process, factors such as oblique waves will affect the measurement results, so a centralized optimal weighted fusion algorithm is introduced; a set of tide level change data is measured at each angle using a millimeter-wave radar, and the mean and standard deviation are calculated for each set of data; at this time, it is assumed that the observation equation of the millimeter-wave radar for the tide level at the i-th angle at time k after suppressing sea clutter is:

[0163] Z i (k) = X(k) + N i (k) i = 1, 2, …, I (18)

[0164] Where, Z i (k) is the data of the millimeter-wave radar's observation of the tide level at time k after filtering out sea clutter, X(k) represents the target state, and N i (k) represents the observation noise of the radar at angle i at time k, mainly Gaussian white noise;

[0165] Then the radar observation noise can simultaneously satisfy:

[0166]

[0167] Where E represents expectation and D represents variance, is the variance value at each moment under the i-th angle;

[0168] The measurement noises of the millimeter-wave radar at each angle are uncorrelated, that is:

[0169]

[0170] The centralized optimal weighted fusion algorithm assigns different weights to the radars at each angle, and weighted operations are performed according to these weights to obtain a virtual measurement value;

[0171]

[0172] Where α i is the weighting coefficient for the millimeter-wave radar to measure the tide level data at the i-th angle. To ensure the unbiasedness of the estimation, it satisfies:

[0173]

[0174] That is, when , is an unbiased estimate of X;

[0175] An estimated mean square error is established, and the expression is:

[0176]

[0177] Use the Lagrange conditional extremum to solve the weighted coefficients of each angle radar when the estimated variance is minimized, with the help of the auxiliary function:

[0178]

[0179] where Λ is the constraint weight in the Lagrange multiplier; thus, a system of equations is established:

[0180]

[0181] Solve the system of equations to obtain:

[0182]

[0183] At this time, the minimum value of the estimated variance is:

[0184]

[0185] By analyzing the expression, it can be found that the weighted coefficient of the data measured by the millimeter-wave radar in each direction is inversely proportional to its corresponding variance; specifically, the smaller the variance of the measured data in a certain direction, the larger the weighted coefficient of the data in that direction, and vice versa, the smaller the weighted coefficient; through such weighted calculation, the weight of the tide level data in the direction with low measurement accuracy and large deviation can be reduced, and the weight of the tide level measurement data in the direction with high measurement accuracy and small deviation can be increased, and finally the variance of the tide level data is less than the variance of the measured data in each direction.

[0186] Such as Figure 6 shown, in step four of this embodiment, the computer host 41 of the remote data display system 4 analyzes the received data, including time, tide level height, wind speed, wind direction and time, and displays the analyzed data on the display 42. At the same time, the data is stored in the database of the computer host 41, and the long-term tide level change data can be analyzed to study its change law and applied in fields such as fishery and meteorology. In this embodiment, the tide level height threshold is set to 2 meters, and the wind speed threshold is set to 10.8 m / s, that is, the wind force intensity threshold is level 6 wind. When the tide level height is greater than the tide level height threshold or the wind speed is greater than the set wind speed intensity threshold, an alarm is triggered, and the display 42 displays the alarm information.

[0187] A tide level monitoring method (algorithm) based on a three-eye lens millimeter-wave radar proposed by the present invention is the underlying technical core of the present invention, and various products can be derived based on the said algorithm.

[0188] The method proposed based on the present invention uses a programming language to develop a tide level monitoring system based on a triple-lens millimeter-wave radar. The system has program modules corresponding to the steps of the above technical solution, and executes the steps in the above-mentioned tide level monitoring method based on a triple-lens millimeter-wave radar when running.

[0189] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art of the present invention can make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. A tide level monitoring device based on trinocular lens millimeter wave radar, characterized in that: The tide level monitoring device comprises four parts: a fixed bracket (1), a three-eye lens millimeter wave radar monitoring system (2), a power supply system (3) and a remote data display system (4); The three-lens millimeter-wave radar monitoring system (2) comprises a millimeter-wave radar monitoring platform (21), an environmental monitoring platform (22) and a communication module (23); the millimeter-wave radar monitoring platform (21) comprises a housing (211), a 77 GHz millimeter-wave radar (212), a millimeter-wave radar lens switching device (213), a pitch rotation device (214) and a data processing controller (215); There is an area below the shell (211) made of wave-transmitting material, and inside the shell (211) are a 77 GHz millimeter wave radar (212) and a millimeter wave radar lens switching device (213); the millimeter wave radar lens switching device (213) is installed below the 77 GHz millimeter wave radar (212), and the environmental monitoring platform (22) includes an anemometer (221) and a wind vane (222); The fixed support (1) comprises a base (11) and a connecting rod assembly; the base (11) is installed on a coast horizontal plane corresponding to the tide level to be monitored, the base (11) is rotatably connected to one end of the connecting rod assembly, and the other end of the connecting rod assembly is respectively connected to the millimeter wave radar monitoring platform (21) and the environmental monitoring platform (22), and the position of the trinocular lens millimeter wave radar monitoring system (2) probing the sea level can be adjusted by the fixed support (1); The three-lens millimeter wave radar monitoring system (2) is used to perform periodic elevation monitoring of sea level tide information through radar, and is also used to monitor the wind speed and wind direction of the tide. The anemometer (221) and the wind vane (222) of the environmental monitoring platform (22) measure the wind speed and wind direction information, and transmit the wind speed and wind direction data to the data processing controller (215). The millimeter wave radar lens switching device (213) is controlled to switch the millimeter wave lens below the 77 GHz millimeter wave radar (212) according to the current wind speed. When the sea waves and wind speed are small, narrow beam millimeter wave monitoring is adopted. When the sea waves and wind speed are large, wide beam millimeter wave monitoring is adopted. The tide data monitored by the 77 GHz millimeter wave radar (212) is transmitted to the data processing controller (215), and the data processing controller (215) optimizes the tide data and transmits it to the remote data display system (4) through the communication module (23); The power supply system (3) is used to supply power to a data processing controller (215), a data storage module, a communication module (23), a millimeter wave radar lens switching device (213), a pitch rotation device (214) and a 77 GHz millimeter wave radar (212); The remote data display system (4) is used to display monitoring data of the trinocular lens millimeter wave radar monitoring system, and to display warning information when the tide level is higher than a threshold.

2. The tide level monitoring device based on trinocular lens millimeter wave radar according to claim 1 is characterized in that: The millimeter wave radar lens switching device (213) comprises an electric steering gear (2131) located in the center and a short focal length focusing lens (2132) and a long focal length focusing lens (2133) located at two ends, the two lenses being connected to the steering gear via short rods respectively, and according to the wind speed, the data processing controller (215) controls the electric steering gear (2131) to rotate, thereby switching the lens below the 77 GHz millimeter wave radar (212).

3. The tide level monitoring device based on trinocular lens millimeter wave radar according to claim 1 is characterized in that: The power supply system (3) is a solar power supply system, which uses solar energy to power the trinocular lens millimeter wave radar tide level monitoring system when there is sunlight. When the power generated by the solar panel exceeds the current demand, the excess power is stored in the battery through the power management module, and continues to supply power at night, on cloudy days or in other low light conditions.

4. A tide level monitoring method based on trinocular lens millimeter wave radar, characterized in that: The method comprises the following steps: Step 1, installing the three-lens millimeter-wave radar monitoring system (2) of claim 1 on the shore of the sea area to be monitored through a fixed bracket (1), adjusting the initial positions of the millimeter-wave radar monitoring platform (21) and the environmental monitoring platform (22) to a horizontal state, so that the 77 GHz millimeter-wave radar (212) should face the sea level, and measuring the wind speed and wind direction information within a working cycle through the anemometer (221) and the wind vane (222); Step 2: After the data processing controller (215) receives the wind direction and wind speed information data, the data processing controller (215) determines that the current wind speed is within a preset wind speed threshold interval, and controls the electric steering gear (2131) according to the threshold interval where the wind speed is located, and rotates the short focal length focusing lens (2132) or the long focal length focusing lens (2133) to below the 77 GHz millimeter wave radar (212), or uses the 77 GHz millimeter wave radar (212) to directly measure without using a lens; Step 3: monitoring the tide level of the monitored sea area, the data processing controller (215) controls the pitch rotation device (214) to rotate, the 77 GHz millimeter wave radar (212) periodically scans the sea area to be monitored, obtains radar monitoring data, suppresses sea clutter in the data through an adaptive clutter suppression algorithm, removes abnormal values ​​in the monitoring data, and then performs data fusion through a centralized optimal weighted fusion algorithm; Step 4: Upload the tide level, wind speed, wind direction and time data to the remote data display system (4) through the communication module (23), draw a tide level change curve, and display an alarm message through the display system when the tide level is higher than the threshold or the wind speed is greater than the threshold.

5. The tide level monitoring method based on trinocular lens millimeter wave radar according to claim 4 is characterized in that: Step 2 specifically includes: after the data processing controller (215) receives the wind direction and wind speed information data, the data processing controller (215) analyzes the wind speed, and if the wind speed is in a low wind state of less than 3m / s, controls the electric steering gear (2131) to rotate the short focal length focusing lens (2132) to below the 77GHz millimeter wave radar (212), and the short focal length focusing lens (2132) converges the beam, so that the narrow beam millimeter wave radar can perform high-precision monitoring of the sea surface tide height; if When the wind speed is in a medium wind state between 3m / s and 6m / s, the electric steering gear (2131) is controlled to rotate the long focal length focusing lens (2133) to the bottom of the 77GHz millimeter wave radar (212), and the long focal length focusing lens (2133) converges the beam, so that the medium beam millimeter wave radar can monitor the sea surface tide level; if the wind speed is in a high wind state greater than 6m / s, the lens is not used, and the 77GHz millimeter wave radar (212) is used to monitor the sea surface tide level.

6. The tide level monitoring method based on trinocular lens millimeter wave radar according to claim 4 is characterized in that: The millimeter wave radar described in step 3 uses a 77GHz frequency modulated continuous wave millimeter wave radar, and the radar's transmission frequency is: Where t is time, f0 is the operating center frequency of the transmitted signal, μ is the modulation slope, B is the modulation bandwidth, and T is the modulation period; The receiving frequency of the radar is: f Re (t)=f0+μ(t-τ)+f d (2) Among them, f d is the Doppler frequency, τ is the propagation time of the signal in the air, assuming that the distance between the millimeter wave radar and the sea level is L, and the speed of light is c, then: Consider the ups and downs of the sea surface as a motion process. Since the surge of the sea waves is a reciprocating motion, they can be balanced and offset in each set of large amounts of data. The Doppler frequency f d If we ignore it, the echo signal model can be expressed as: Where K is the scaling factor constant, A is the signal amplitude, and φ0 is the initial phase of the signal; The phase of the echo signal is expressed as: The phase of the radar difference frequency signal is expressed as: p m (t)=p Tr (t)-p Re (t)=2πf0τ+2πμτt-πμτ 2 (6) Based on the phase p of the radar difference frequency signal m (t) Solve the radar difference frequency signal frequency: get:

7. The tide level monitoring method based on trinocular lens millimeter wave radar according to claim 6 is characterized in that: Step 3 describes suppressing sea clutter in the data through an adaptive clutter suppression algorithm, specifically: For the echo signal model y R (t) is discretized, and the observation equation of the millimeter wave radar for the tide level at angle i is: Y i (k)=X(k)+C i (k)+N i (k) i=1,2,…,I (9) Among them, Y i (k) is the observed signal of the target at time k, X(k) is the target signal at time k, C i (k) is the clutter signal, N i (k) is a Gaussian white noise signal, I is the number of observation angles; The echo signals of different distance units and their adjacent range gates are {y i,j (k)|i=1,2,…,I;j=1,2,…,J}, where J is the number of range gates, representing the echo signals at different distances measured by the radar; the echo data of different range gates satisfy independent and identical distribution, then based on all sea clutter sub-signals C i (k) is the covariance matrix R C for: Where p is the filter order, r C (·) is the clutter autocorrelation function, is the complex conjugate of the clutter autocorrelation function, r C The expression of (·) is: Where m represents the delay of the signal when calculating the autocorrelation; The covariance matrix R C Perform eigenvalue decomposition to obtain the eigenvalue λ i and the eigenvalue λ i The corresponding eigenvector W i : R C W i =λ i W i (12) Eigenvalues ​​of the sea clutter covariance matrix λ i The minimum value of λ min The corresponding eigenvector is the optimal weighting coefficient of the adaptive clutter suppression algorithm, denoted as W0. The echo signal after suppressing sea clutter is: WITH i (k)=W0Y i (k) (13)。 8. The tide level monitoring method based on trinocular lens millimeter wave radar according to claim 7 is characterized in that: The removal of outliers in the monitoring data described in step 3 is specifically as follows: For the millimeter-wave radar ranging data at each angle, calculate the vertical distance d between the millimeter-wave radar monitoring platform and the sea surface: Among them, α is the angle between the millimeter wave radar antenna surface and the horizontal plane; A set of tidal height data is obtained, and then the cyclic monitoring is continued; the outliers in the tidal height data are removed by the Grubbs test method, that is, the average value is first calculated for: Where n is the amount of data measured at each angle, and the standard deviation S is calculated as: The calculated G value is: According to the Grubbs criterion discriminant coefficient table, find the coefficient G corresponding to the sample size n and confidence q of a set of tide data. 表 , if G 表 >G 计算 , it is judged as abnormal data and removed, otherwise it is retained.

9. The tide level monitoring method based on trinocular lens millimeter wave radar according to claim 8 is characterized in that: The data fusion described in step 3 is performed by a centralized optimal weighted fusion algorithm, specifically: a set of tidal level change data is measured at each angle using the millimeter-wave radar, and the mean and standard deviation are calculated for each set of data; assuming that the observation equation of the tidal level at the i-th angle of the millimeter-wave radar at time k after suppressing sea clutter is: Z i (k)=X(k)+N i (k) i=1,2,…,I (18) Radar observation noise satisfies: Where E represents expectation and D represents variance. is the variance value at each moment under the i-th angle; The measurement noise of millimeter-wave radar at different angles is uncorrelated, that is: Different weights are given to the radar at each angle to obtain a virtual measurement value; where α i is the weighting coefficient of the millimeter-wave radar tide data measured at the i-th angle. To ensure the unbiasedness of the estimate, it satisfies: When hour, is an unbiased estimate of X; Establish the estimated mean square error, the expression is: The weighted coefficients of radars at each angle when the estimated variance is minimized are solved using the Lagrangian conditional extreme value solution, with the help of the auxiliary function: Where Λ is the constraint weight in the Lagrange multiplier; thus the equation system is established: Solving the system of equations yields: At this time, the estimated variance is minimized as:

10. A tide monitoring system based on trinocular lens millimeter wave radar, characterized in that: The system has a program module corresponding to the steps of the method described in any one of claims 4 to 9, and executes the steps of the tide level monitoring method based on trinocular lens millimeter wave radar when running.

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