A low-altitude wind phased array acoustic detection radar device

Abstract

This application discloses a low-altitude wind phased array acoustic detection radar device, comprising: a phased array antenna array, a transmitting unit, a receiving unit, a beam control unit, and a data processing unit. The phased array antenna array comprises a plurality of reversible transceiver transducers forming an equidistant square array, wherein transducers in the same row have the same operating frequency, and transducers in different rows have different operating frequencies. The transmitting unit is used to output a transmit signal to the phased array antenna array; the receiving unit is used to receive the echo signal from the phased array antenna array; the beam control unit includes a transceiver switching device for controlling the transceiver switching of the phased array antenna array; and the data processing unit is used to receive and intelligently process the echo signal. The advantages of this application are better intelligent noise suppression, which facilitates obtaining more accurate weather detection information.

Description

Technical Field

[0001] The present application relates to the field of meteorological detection technology, and in particular to a low-altitude wind phased array acoustic detection radar device. Background Art

[0002] Traditional low-altitude meteorological detection mainly uses wind towers for measurement. This requires the construction of 100m or even 200m high iron towers and the installation of meteorological detection sensors on the towers to achieve low-altitude meteorological detection. This detection method has complex equipment construction, high costs, poor maintenance, and lacks mobility, which has great limitations in applicability.

[0003] As an emerging wind measurement technology, sodar wind measurement has been widely promoted and applied due to its wide detection range, high reliability, ease of use, low cost, and excellent cost-effectiveness. Sodar transmits strong sound pulses of a specific frequency in a targeted manner, receives the scattered sound echoes, analyzes the intensity of the scattered sound echoes, and compares the difference in frequency between the transmitted sound waves and the scattered sound echoes. This allows calculation of wind direction, wind speed, and vertical airflow changes over time and altitude.

[0004] Due to its inherent technical principles and application scenarios, sodar inevitably generates noise. The echo signal contains a variety of noise types and strong noise signals, which adversely impacts subsequent signal processing. Currently, sodar noise suppression involves physical noise reduction in the antenna assembly and noise reduction at the signal receiving end through filters and software. However, due to the complexity of the echo signal noise, achieving effective noise reduction remains difficult, adversely impacting weather forecasting, particularly wind and cloud measurement. Summary of the Invention

[0005] The present application provides a low-altitude wind phased array acoustic detection radar device, which has the advantage of having better noise suppression effect and is conducive to obtaining more accurate weather detection information.

[0006] The above-mentioned object of the present application is achieved through the following technical solutions: a low-altitude wind phased array acoustic detection radar device, comprising:

[0007] A phased array antenna array, wherein the phased array antenna array includes a plurality of reversible transceiver transducers forming an equally spaced square array, wherein transducers in the same row have the same operating frequency, and transducers in different rows have different operating frequencies;

[0008] A transmitting unit, configured to output a transmission signal to a phased array antenna array;

[0009] A receiving unit, configured to receive an echo signal from a phased array antenna;

[0010] A beam control unit, the beam control unit including a transceiver switching device for controlling the transceiver switching of the phased array antenna array;

[0011] and a data processing unit for receiving and intelligently processing echo signals.

[0012] Furthermore, in the phased array antenna array, the operating frequency of each row of transducers gradually increases.

[0013] Furthermore, in the phased array antenna array, the operating frequencies of the transducers in each row are distributed equidistantly. Specifically, the operating frequencies of the transducers in each row are:

[0014]

[0015] in, is the operating frequency of the transducer in the i-th row, To set the reference frequency, is the operating frequency difference between adjacent rows of transducers.

[0016] Furthermore, the transmitting unit has several channels, each used to transmit signals to different rows of transducers, and the output signal frequency of each channel is adapted to the operating frequency of each row of transducers.

[0017] Furthermore, the receiving unit has several paths, each used to receive echo signals from transducers in different rows, and each path includes a transceiver switch, a transformer, a low noise amplifier, a filter and a programmable gain amplifier.

[0018] Furthermore, the transceiver switching device includes several solid-state electronic relays and a drive circuit connected in parallel. The drive circuit receives the transceiver switching control signal sent by the host computer and controls the action of the solid-state electronic relay. The solid-state electronic relay is used to control the connection between the phased array antenna array and the receiving unit or the transmitting unit.

[0019] Furthermore, the data processing unit includes a noise processing unit, which is used to intelligently suppress noise in the echo signal, and the steps are:

[0020] Perform fast Fourier transform on the obtained echo signals to obtain ,in, represents the fast Fourier transform result of the j-th echo signal;

[0021] Compare the transformed echo signals, mark the frequency signals whose amplitude differences among the echo signals are within the preset value as noise signals and delete them to obtain , It represents the result after removing noise from the j-th echo signal.

[0022] Furthermore, any n-way signal Where n is a positive integer greater than or equal to 2 and less than the number of rows of the phased array antenna. For a signal of any frequency, if the amplitude ratio difference is less than τ, where τ is a preset threshold, the frequency signal is judged to be a noise signal.

[0023] Furthermore, the sodar device also includes an antenna heating device, which includes an automatic temperature controller, a temperature sensor and a heating cable. The heating cable is coiled at the bottom of the transducer. The temperature sensor is arranged in the phased array antenna array or next to the phased array antenna array to detect the temperature of the phased array antenna array. The automatic temperature controller is used to control the heating cable to be energized when the temperature of the phased array antenna array is lower than a set value.

[0024] Furthermore, the sonar device also includes an antenna cover, the opening of the antenna cover gradually increases, the phased array antenna array is installed at the bottom of the antenna cover, and a sound-absorbing sponge or sound-absorbing panel is provided inside the antenna cover; a protective net is provided at the opening of the antenna cover.

[0025] Furthermore, the sonar device also includes an ultrasonic wind measuring device, an ultrasonic wind measuring instrument and a manual lifting rod. The ultrasonic wind measuring instrument includes a relatively arranged transmitting surface and a reflecting surface. The transmitting surface and the reflecting surface are both arc-shaped. Four ultrasonic probes are arranged on the transmitting surface, and the ultrasonic probes are integrated with transmitting and receiving.

[0026] Furthermore, the manual lifting rod includes an external fixed rod, an internal telescopic rod, a fixed base, a clamp fixing seat, a locking sleeve, a movable buckle, a limit pin, and an internal guide sleeve, wherein the fixed base and the clamp fixing seat are arranged on a fixed object, the external fixed rod is installed on the fixed base and the clamp fixing seat to achieve fixation, the internal telescopic rod is arranged in the external fixed rod and can be telescopically moved, the locking sleeve is arranged at the end of the external fixed rod, and has a movable buckle on it for adjusting the locking progress of the locking sleeve, when locked, the internal telescopic rod is clamped and fixed by the external fixed rod, and when not locked, the internal telescopic rod can be manually extended and retracted to adjust the extension height of the internal telescopic rod.

[0027] To sum up, the beneficial effects of the present application are: the present application obtains echo detection signals of different frequencies through transducers of different operating frequencies, and then compares the same parts in different echo detection signals to identify noise that is difficult to filter out, thereby improving the denoising effect, which is conducive to obtaining more accurate meteorological detection data. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of a low-altitude wind sound detection radar in a specific embodiment of the present application;

[0029] Figure 2 This is a schematic diagram of a radome in a specific embodiment of the present application;

[0030] Figure 3 This is a schematic diagram of a phased array antenna array in a specific embodiment of the present application;

[0031] Figure 4 This is a schematic diagram of an antenna heating device in a specific embodiment of the present application;

[0032] Figure 5 This is a schematic diagram of the emitting surface and reflecting surface of an ultrasonic anemometer in a specific embodiment of the present application;

[0033] Figure 6 This is a schematic diagram of ultrasonic signal transmission of an ultrasonic anemometer in a specific embodiment of the present application;

[0034] Figure 7 This is a schematic diagram of the principle of an ultrasonic anemometer in a specific embodiment of the present application;

[0035] Figure 8 This is a schematic diagram of the principle of ultrasonic wind measurement in a specific embodiment of the present application;

[0036] Figure 9 is a schematic diagram of a sound host in a specific embodiment of the present application;

[0037] Figure 10 This is a schematic diagram of the principle of a transceiver switching device in a specific embodiment of the present application;

[0038] Figure 11 It is a schematic diagram of the acoustic detection radar beam;

[0039] Figure 12 This is a three-dimensional diagram of the "west beam" array simulation in a specific embodiment of the present application;

[0040] Figure 13 is the normalized plane lobe of the beam in a specific embodiment of the present application Figure 1 ;

[0041] Figure 14 is the normalized plane lobe of the beam in a specific embodiment of the present application Figure 2 ;

[0042] Figure 15 This is a schematic diagram of the principle of a receiving unit in a specific embodiment of the present application;

[0043] Figure 16 This is a schematic diagram of the principle of the sonar host in a specific embodiment of the present application;

[0044] Figure 17 This is a functional block diagram of a data processing module in a specific embodiment of the present application;

[0045] Figure 18 is a schematic diagram of data processing software in a specific embodiment of the present application;

[0046] Figure 19 It is a flowchart of the data processing software in a specific embodiment of the present application. DETAILED DESCRIPTION

[0047] The specific implementation of the present application is described in detail below with reference to the accompanying drawings.

[0048] Embodiment 1: A low-altitude wind phased array acoustic detection radar device includes a phased array antenna array, a transmitting unit, a receiving unit, a beam control unit and a data processing unit.

[0049] refer to Figure 3 The phased array antenna array includes multiple reversible transceiver transducers forming an evenly spaced square array. Transducers in the same row have the same operating frequency, while transducers in different rows have different operating frequencies. For example, in this embodiment, the phased array antenna array includes 64 reversible transceiver transducers arranged in an even "8×8" pattern. The transducers are 24×20 mm in size and spaced 30 mm apart, forming a 234 mm×234 mm square array.

[0050] In the phased array antenna, the operating frequency of each row of transducers gradually increases.

[0051] In particular, in this embodiment, the operating frequencies of the transducers in each row of the phased array antenna are distributed equidistantly. Specifically, the operating frequencies of the transducers in each row are:

[0052]

[0053] in, is the operating frequency of the transducer in the i-th row, To set the reference frequency, is the operating frequency difference between adjacent rows of transducers.

[0054] As an example, for an 8×8 phased array antenna array, 20KHz, is 5KHz.

[0055] The transmitting unit is used to output a transmitting signal to the phased array antenna array; the transmitting unit has several paths, each used to transmit a signal to a different row of transducers, and the output signal frequency of each path is adapted to the operating frequency of each row of transducers.

[0056] refer to Figure 15The receiving unit is used to receive echo signals from the phased array antenna array. The receiving unit has several paths, each for receiving echo signals from different rows of transducers. Each path includes a transceiver switch, a transformer, a low-noise amplifier, a filter, and a programmable gain amplifier. Because the echo signals are relatively weak, they are amplified with a certain gain using a low-noise, low-drift operational amplifier. To achieve optimal impedance matching with the receiving transducer, a transformer is used for impedance transformation. Because environmental noise contains strong interference signals, a differential amplifier is introduced after the transformer to prevent the interference signals from generating unnecessary multiple harmonics after high-gain amplification. The gain of the preamplifier circuit is controlled at approximately 60dB. After preamplification, the signal first passes through a bandpass filter, primarily based on the bandwidth of the transmitted signal, to filter out interference noise. Then, amplification and filtering with varying gains are performed based on the signal strength. The received signal is then sent to the data processing module, achieving a receive gain exceeding 100dB.

[0057] For an 8×8 phased array antenna array, both the transmitting unit and the receiving unit have 8 channels, corresponding to 8 rows of transducers respectively.

[0058] refer to Figure 10 The beam control unit includes a transceiver switching device, which is used to control the transceiver switching of the phased array antenna array. The transceiver switching device includes several parallel solid-state electronic relays and a drive circuit. The drive circuit receives the transceiver switching control signal sent by the host computer and controls the operation of the solid-state electronic relays. The solid-state electronic relays are used to control the connection between the phased array antenna array and the receiving unit or the transmitting unit. It can be understood that for an 8×8 phased array antenna array, the number of solid-state electronic relays is 8, 16, or 64, and the solid-state electronic relays are used to switch between the receiving unit and the transmitting unit.

[0059] The data processing unit is used to receive and intelligently process the echo signal. The data processing unit includes a noise processing unit, which is used to intelligently suppress noise in the echo signal. The steps are as follows:

[0060] Perform fast Fourier transform on the obtained echo signals to obtain ,in, represents the fast Fourier transform result of the j-th echo signal;

[0061] Compare the transformed echo signals, mark the frequency signals whose amplitude differences among the echo signals are within the preset value as noise signals and delete them to obtain , It represents the result after removing noise from the j-th echo signal.

[0062] The part of the noise whose frequency is within the filter bandpass is not easily removed by the filter, and the noise will be received approximately equally by the transducers in each row. Therefore, by comparing the transformed echo signals of several paths, the signal frequency with equal or close amplitude is the noise.

[0063] Furthermore, any n-way signal Where n is a positive integer greater than or equal to 2 and less than the number of rows of the phased array antenna. For a signal of any frequency, if the amplitude ratio difference is less than τ, where τ is a preset threshold, the frequency signal is judged to be a noise signal.

[0064] The portion of the noise close to the transducer operating frequency still exists in the previous processing step. By comparing n signals, where n is a positive integer greater than or equal to 2 and less than the number of rows in the phased array antenna, and for an 8×8 phased array antenna array, n is any positive integer between 2 and 7, the noise close to the operating frequency of a certain transducer can be found.

[0065] The denoised data is then output to a separate host computer for data analysis to obtain meteorological data, which is an existing technology and will not be described in detail here.

[0066] The present application uses a filter to remove noise outside the passband, and then uses the solution of the present application to remove noise within the passband and noise close to the transducer frequency, thereby achieving a better denoising effect.

[0067] Example 2: A low-altitude wind phased array acoustic detection radar device, referring to Figure 1 , including a sonar host, an ultrasonic wind measuring device and a phased array acoustic antenna device.

[0068] The phased array acoustic antenna device includes a radome, a protective net, and a phased array antenna array, and the phased array antenna array is the same as the phased array antenna array of the first embodiment. Figure 2 The opening of the radome gradually increases in size and is horn-shaped. The phased array antenna array is mounted on the bottom of the radome. Sound-absorbing sponges and panels are located within the radome to remove ambient noise. The radome is constructed of two-component polyurethane (PU), and the transducer array is molded from nylon fiberglass. A protective net is located at the top of the radome (i.e., its opening) to protect the sonar antenna from falling objects. The protective net is constructed of metal, particularly rust-resistant aluminum, which is treated with three-proofing treatment to ensure long-term reliable outdoor operation. For example, the longitudinal and transverse spacing of the protective net is 85 mm.

[0069] refer to Figure 4The low-altitude wind sound detection radar also includes an antenna heating device, which includes an automatic temperature controller, a temperature sensor, and a heating cable. The heating cable is coiled at the bottom of the transducer. The temperature sensor is located in or next to the phased array antenna array to detect the temperature of the phased array antenna array. The automatic temperature controller is used to control the heating cable to operate when the temperature of the phased array antenna array falls below a set value. When the power switch of the antenna heating device is closed, the automatic temperature controller begins to operate. Heating is activated when the outside temperature is detected to be below 0°C; heating is stopped when the temperature rises to 20°C. In winter, when it snows, snow may accumulate inside the antenna. The antenna heating device can be used to defrost and remove snow.

[0070] The ultrasonic wind measuring device is used to detect surface winds and output the results to the sonar host. It consists of an ultrasonic anemometer and a manual lift. The ultrasonic anemometer is housed in an aluminum alloy housing that is anodized and then painted. In this embodiment, the dimensions of the ultrasonic anemometer and housing are 64 mm in diameter, 68 mm in height, and weigh 1 kg. The housing is manually raised and lowered.

[0071] The manual lifting rod includes an outer fixed rod, an inner telescopic rod, a fixed base, a clamp mount, a locking sleeve, a snap lock, a limit pin, and an internal guide sleeve. The fixed base and the clamp mount are mounted on a fixed object, which can be a wall, a steel frame, a vehicle, etc., depending on the application scenario of the sodar. The fixed base is welded from high-strength stainless steel. The outer fixed rod is mounted on the fixed base and the clamp mount to achieve fixation. One end of the outer fixed rod is fixedly connected or rotatably connected to the fixed base, and the other end is fixed by the clamp mount. The inner telescopic rod is mounted inside the outer push rod and can be telescopically moved. The locking sleeve is mounted on the end of the outer fixed rod and has a snap lock on it. The snap lock can be spiral or wedge-shaped, both of which are existing technical solutions and are used to adjust the locking degree of the locking sleeve. When locked, the inner telescopic rod is clamped and fixed by the inner telescopic rod. When unlocked, the inner telescopic rod can be manually extended and retracted to adjust the extension height of the inner telescopic rod. An internal guide sleeve is installed within the outer fixing rod, contacting the inner telescopic rod and reducing friction. Made of wear-resistant polytetrafluoroethylene (PTFE), the sleeve primarily serves as a guide, preventing the telescopic rod from becoming unstable when extended due to excessive height. A stop pin is installed in the side of the outer fixing rod and extends into a long slot in the inner telescopic rod's side, limiting the extension and retraction of the inner telescopic rod. When the stop pin reaches the upper and lower dead centers of the slot, it prevents the inner telescopic rod from retracting into the outer fixing rod or dislodging. The outer fixing rod is made of cold-drawn stainless steel tubing, offering high strength and excellent resistance to deformation. The inner telescopic rod is made of cold-drawn aluminum tubing, offering high strength and low weight, allowing for easy manual extension and lowering. Furthermore, when extended and fixed, it prevents the rod from sliding due to its own weight. The ultrasonic anemometer is connected via a threaded hole in the top of the inner telescopic rod and secured with a matching nut. For example, the maximum extension height of the manual lift rod is 300 mm, providing the necessary working height for the ultrasonic anemometer.

[0072] The ultrasonic anemometer consists of an upper plate and a lower plate, separated by a gap and connected by a central column. It has an overall hourglass shape. It includes an arc-shaped transmitting and reflecting surface, both of which are opposed to each other. Four ultrasonic probes are located on the transmitting surface, each of which is an integrated transmitter and receiver.

[0073] refer to Figure 5-7According to the principle of ultrasonic wind measurement, wind speed and direction are calculated based on the time or frequency difference between the transmission of an ultrasonic wave at the transmitter and the reception of the wave at the receiver. If the distance between the transmitter and the receiver is short, the path of the transmitted signal is short. The receiver may not have avoided the aftershock signal of the transmitted signal and may not be able to properly receive the transmitted signal, resulting in calculation errors in the ultrasonic anemometer. Therefore, the transmitted signal of the ultrasonic anemometer needs to travel a sufficiently long path to maximize the time or frequency difference between the transmission of the ultrasonic wave at the transmitter and the reception of the ultrasonic wave at the receiver. To reduce the size of the ultrasonic anemometer, the ultrasonic anemometer in this embodiment uses four ultrasonic probes mounted on the transmitting surface. A reflecting surface is arranged opposite the transmitting surface and separated by a preset distance. Both the transmitting surface and the reflecting surface are curved surfaces. The signal emitted by the ultrasonic probe undergoes multiple reflections from the transmitting and reflecting surfaces before being received by the receiving probe. Even if the preset distance between the transmitting and reflecting surfaces is small, the reflected signal undergoes multiple reflections before being received by another ultrasonic probe. Therefore, the reflected signal has a long reflection path, which can avoid the influence of the aftershock signal of the transmitted signal. On the one hand, the calculation accuracy of the ultrasonic anemometer can be improved, and on the other hand, the preset distance between the emitting surface and the reflecting surface can be very small, thereby reducing the volume of the ultrasonic anemometer.

[0074] The beam opening angle of the transmitting signal of the selected ultrasonic probe is greater than 60°. On the one hand, it can ensure that the transmitting signal undergoes multiple reflections in the cavity of the transmitting shell and the reflecting shell. The longer the reflection path of the reflected signal, the further the preset distance between the reflecting shell and the transmitting shell can be shortened. On the other hand, after each ultrasonic transmitting signal reaches the reflecting surface, it is reflected to both sides respectively. Since multiple ultrasonic probes are evenly distributed on the transmitting surface, the transmitting signal of each ultrasonic probe can be received by its two adjacent ultrasonic probes at the same time. By obtaining more ultrasonic transmission and reception data, the accuracy of wind speed measurement of the ultrasonic anemometer is improved, and the measurement performance of the ultrasonic anemometer is improved.

[0075] In order to measure the wind speed and direction in each direction, the ultrasonic anemometer uses two pairs of probes to measure the wind speed in two horizontal directions at the same time in the directions perpendicular to each other on the horizontal plane, and then calculates the wind direction and speed on the horizontal plane by orthogonal synthesis, and transmits it to the sonar host through the serial port for fusion with the sonar data and sends it to the upper system. The schematic diagram of the ultrasonic anemometer is as follows: Figure 7 shown.

[0076] refer to Figure 8 , the ground wind is measured by an ultrasonic anemometer. Ultrasonic wave is the propagation process of mechanical vibration in the medium. If two pairs of ultrasonic probes are placed parallel along the X direction in the wind field, T1 and T2 are for transmission, and R1 and R2 are for reception, and the distance between them is L.

[0077] Assume that the speed of sound in the air in the absence of wind is C, the component of the wind speed V along the X direction is Vx, and the component along the plane perpendicular to the X axis is Vy. The propagation times from T1 to R1 and from T2 to R2 in the forward and reverse directions are:

[0078] (1)

[0079] (2)

[0080] If the distance L is much larger than the wavelength of the sound wave, the sound wave can be simplified as a plane wave. In this case, the propagation time of the sound wave in the X direction is only related to the wind speed in the X direction. Then (1) and (2) can be simplified as:

[0081] (3)

[0082] (4)

[0083] From equations (3) and (4), we can get:

[0084]

[0085] Therefore, by measuring the ultrasonic propagation time from the application of an excitation pulse to the transmitting probe to the receipt of the first pulse by the receiving probe in a certain direction, both with and without wind, the wind speed in that direction can be calculated. If wind speed components are measured in two different directions, the total wind speed and direction can be calculated based on the principle of vector synthesis. Because the measurement method is symmetrical, the measurement results are independent of sound velocity, eliminating the need for complex real-time sound velocity correction.

[0086] The sonar host generates an acoustic emission signal; controls the phased array antenna to produce a specified beam; amplifies the acoustic echo signal received by the phased array antenna, processes the data, and outputs wind direction and speed at each altitude. It also records ground wind direction and speed data from the ultrasonic wind measuring device, fuses the data, and outputs it to the host computer system. The ultrasonic wind measuring device detects ground winds and transmits this data to the sonar host. The sonar host is housed in a chassis and is located below the phased array acoustic antenna.

[0087] refer to Figure 9 、 16 The sonar host consists of a power module, signal processing module, receiving module, transmitting module, and beam control module. When the sonar radar is operating, the host generates a short pulse signal, which is amplified by the transmitting module and sent to the antenna. The antenna then transmits the acoustic pulse signal into the lower atmosphere. This pulse signal propagates in a directionally controlled manner in the atmosphere.

[0088] The data processing module receives commands from the host computer system, pre-sets its operating state accordingly, generates the acoustic wave signal required by the transmitter module, and transmits it via the beam steering module to the acoustic array antenna. The acoustic array antenna forms a prescribed beam according to the beam steering module and transmits it. It then receives the acoustic echo signal and transmits it to the receiver module via the beam steering network. The receiver module amplifies the signal, processes it, and transmits it to the data processing module. The data processing module then performs beam synthesis, signal extraction, accumulation, and processing based on the received signal to obtain the echo power spectrum. The data processing module then calculates wind direction and speed based on the Doppler frequency shift signals on each beam, corrects them based on attitude information, and fuses the data with the surface wind measured by the ultrasonic wind measuring device. The data is then transmitted to the host computer system via the network in the specified format. The power supply module stabilizes and filters the 28V DC signal provided by the host computer system, outputting the DC voltage required by each unit.

[0089] refer to Figure 10 The beam control module completes the switching between the five beams of the phased array antenna, namely the east, south, west, north and center, and forms five transmit beams and five receive beams through the transmit / receive switching. The beam switching is completed by the transmit / receive switching device through 16 solid-state electronic relays. The transmit / receive switching device is the same as the transmit / receive switching device in Example 1.

[0090] When an acoustic detection radar is operating, the sonar host generates a short pulse signal, which is amplified by the transmitter module and sent to the antenna. The antenna then transmits the acoustic pulse signal into the lower atmosphere. This pulse signal propagates directionally through the atmosphere; when the transmitted signal encounters atmospheric turbulence, various scattering occurs. When the scale of the isotropic turbulence is comparable to the wavelength of the sound wave, the scattering is strongest, and the echo that is opposite to the transmission direction is called the backscattered echo. The acoustic detection radar antenna receives the backscattered echo and sends it to the receiving module through the beam control module. The receiving module amplifies and filters the signal and sends it to the data processing module. The data processing module collects and processes the echo signal in that direction, deriving the Doppler frequency shift in that radial direction and converting it into radial wind speed.

[0091] Acoustic radar measurement of three-dimensional wind speed requires the synthesis of three radial wind speeds that are not in the same plane. This application uses a five-beam method, one vertical beam and four inclined beams with an inclination angle between 15 and 30 degrees, and located in two mutually perpendicular planes, such as Figure 11 shown.

[0092] From the relationship between radial wind speed and Doppler shift , get

[0093] ,

[0094] Where C is the speed of sound in air when there is no wind, λ is the wavelength of the sound wave, is the sound wave frequency, is the wind speed, The frequency shift of the sound wave.

[0095] By calculating the radial Doppler frequency, the wind speed in each radial direction can be obtained. is the wind speed in the radial direction of the beam, U, V, and W represent the components of the wind speed vector in the east, north, and vertical directions, respectively. is the beam tilt angle, then

[0096]

[0097]

[0098]

[0099]

[0100]

[0101] Thus there is

[0102]

[0103] U and V are two components of the horizontal wind speed, and then they are combined into the horizontal wind speed to get the horizontal wind speed. and offset angle They are

[0104]

[0105] in It is a constant determined by the positive and negative values ​​of U and V.

[0106] In a specific scenario, the phased array antenna array is arranged from west to east, and the phase of each column is advanced by 90 degrees in sequence, so that the transmission beam can be controlled to tilt westward. The three-dimensional simulation diagram of the "west beam" corresponding to the phased array antenna array is shown as follows: Figure 12 The normalized plane lobe pattern of the beam is shown as Figure 13-14 shown.

[0107] And so on:

[0108] From west to east, the phase of each column lags by 90 degrees, which controls the transmit beam to tilt eastward;

[0109] From north to south, the phase of each row advances by 90 degrees, which controls the transmit beam to tilt toward the north.

[0110] From north to south, the phase of each row lags by 90 degrees, which controls the transmit beam to tilt south.

[0111] When all array elements are in phase, the transmitted beam points vertically upward.

[0112] All array elements have four phases: 0°, 90°, 180°, and 270°. Since the phases of 0° and 180°, and 90° and 270° differ by 180°, a phase inverter can be used to generate two oppositely phased signals. Therefore, only two signals with a 90° phase difference are needed to generate the oblique beam shown in the figure. When these two signals are in phase, a vertical beam is generated. This is the principle of phased array transmission.

[0113] The data processing module mainly completes the generation of transmission waveform, echo signal acquisition, transceiver signal array control, digital beamforming processing, signal-to-noise ratio optimization processing, layered power spectrum processing, wind parameter calculation, communication interface, etc. The functional block diagram of the data processing module is as follows Figure 17 The data processing module is implemented using Analog Devices' low-power ADSP-SC589 DSP circuitry. Consuming less than 2W at high temperatures, the ADSP-SC589 delivers industry-leading digital signal processing performance. The ADSP-SC589 complements the SHARC+ core and DSP accelerator family, adding an ARM® Cortex-A5 processor, an FPU, and Neon® DSP extensions to handle additional real-time processing tasks and manage peripherals. These interfaces include Gigabit Ethernet, high-speed USB, serial ports, removable storage, and a variety of other connectivity options, enabling flexible and streamlined system designs.

[0114] The data processing module is equipped with intelligent data processing software, refer to Figure 18 ,The data processing software includes signal self-test module, signal generation module, beam control module, signal acquisition and processing module, data fusion and processing module, and data communication module. Figure 19 The software workflow is as follows: After the system is powered on, it performs a self-test. If the self-test fails, an error message is displayed and the system stops. If the self-test is normal, the system proceeds to detect ambient noise. It then waits for commands from the host computer and waits for a start command to begin measurement. It first transmits a waveform, then receives and processes the echo data, saving the intermediate results. At the end of each subframe processing, the real-time clock is used to determine whether the frame time has expired. If not, the process repeats for the next subframe. If so, the frame data processing function is called to organize the data from each subframe within the frame, obtain the final result, and transmit it.

[0115] In a specific application scenario, the low-altitude wind detection radar is installed on a vehicle, a recess or mounting bracket is provided on the top of the vehicle for installing the low-altitude wind detection radar, and the ultrasonic wind measuring device is installed on the side of the vehicle.

[0116] The low-altitude wind phased array acoustic detection radar device in this embodiment is primarily used to detect wind direction, wind speed, and vertical airflow at specified altitudes between 0 and 200 meters. Its effective detection altitude can even reach 500 meters. Compared to wind profiler radars and sounding balloons, the low-altitude wind phased array acoustic detection radar device in this embodiment has higher low-altitude wind detection accuracy and provides vertical airflow detection capabilities, which are not available in wind profiler radars and sounding balloons.

[0117] The low-altitude wind phased array acoustic detection radar device in this embodiment has a primary detection range of: a) altitude: 0 m to 200 m (55 dBA, humidity 70% RH); b) wind speed: 0 m / s to 30 m / s; c) wind direction: 0 to 360 degrees. The measurement accuracy is: a) wind speed: ≤ 1 m / s (wind speed less than 10 m / s), ≤ 10% of the wind speed (wind speed greater than 10 m / s); b) wind direction: ≤ 10° (wind speed greater than 2 m / s); c) vertical airflow: ≤ 0.5 m / s.

[0118] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this field, several variations and improvements can be made without departing from the creative concept of the present application, and these all fall within the scope of protection of the present application.

Claims

1. A low-altitude wind phased array acoustic detection radar device, characterized in that: include: A phased array antenna array, wherein the phased array antenna array includes a plurality of reversible transceiver transducers forming an equally spaced square array, wherein the transducers in the same row have the same operating frequency, and the transducers in different rows have different operating frequencies, and the operating frequencies of the transducers in each row of the phased array antenna array are equidistantly distributed; A transmitting unit, configured to output a transmission signal to a phased array antenna array; A receiving unit, configured to receive an echo signal from a phased array antenna; A beam control unit, the beam control unit including a transceiver switching device for controlling the transceiver switching of the phased array antenna array; and a data processing unit for receiving and intelligently processing echo signals; The data processing unit includes a noise processing unit, which is used to intelligently suppress noise in the echo signal, and the steps are as follows: Perform fast Fourier transform on the echo signals to obtain X j , where X j represents the fast Fourier transform result of the j-th echo signal; Compare the transformed echo signals, mark the frequency signals whose amplitude differences among the echo signals are within the preset value as noise signals and delete them to obtain It represents the result after noise removal of the j-th echo signal; Any n-way signal X j Where n is a positive integer greater than or equal to 2 and less than the number of rows of the phased array antenna. For a signal of any frequency, if the amplitude ratio difference is less than τ, where τ is a preset threshold, the frequency signal is judged to be a noise signal. The radar device also includes an ultrasonic wind measuring device, which includes an ultrasonic anemometer and a manual lifting rod. The ultrasonic anemometer includes an emitting surface and a reflecting surface that are relatively arranged. The emitting surface and the reflecting surface are both arc-shaped. Four ultrasonic probes are arranged on the emitting surface, and the ultrasonic probes are integrated with transmitting and receiving.

2. The low-altitude wind phased array acoustic detection radar device according to claim 1, characterized in that: The specific operating frequency of each row of transducers is: in i =f0+iδ Among them, f i is the operating frequency of the i-th row transducer, f0 is the set reference frequency, and δ is the set operating frequency difference between adjacent rows of transducers.

3. The low-altitude wind phased array acoustic detection radar device according to claim 2, characterized in that: The transmitting unit has several channels, each used to transmit signals to different rows of transducers, and the output signal frequency of each channel is adapted to the operating frequency of each row of transducers; The receiving unit has several paths for receiving echo signals from transducers in different rows respectively. Each path includes a transceiver switch, a transformer, a low noise amplifier, a filter and a programmable gain amplifier.

4. The low-altitude wind phased array acoustic detection radar device according to claim 1, characterized in that: The radar device also includes an antenna heating device, which includes an automatic temperature controller, a temperature sensor and a heating cable. The heating cable is coiled at the bottom of the transducer. The temperature sensor is arranged in or next to the phased array antenna array to detect the temperature of the phased array antenna array. The automatic temperature controller is used to control the heating cable to be energized when the temperature of the phased array antenna array is lower than a set value.

5. The low-altitude wind phased array acoustic detection radar device according to claim 1, characterized in that: The radar device also includes an antenna cover, the opening of which gradually increases, the phased array antenna array is installed at the bottom of the antenna cover, and a sound-absorbing sponge or sound-absorbing panel is provided inside the antenna cover; a protective net is provided at the opening of the antenna cover.

6. The low-altitude wind phased array acoustic detection radar device according to claim 1, characterized in that: The manual lifting rod includes an external fixed rod, an internal telescopic rod, a fixed base, a clamp fixing seat, a locking sleeve, a movable buckle, a limit pin, and an internal guide sleeve, wherein the fixed base and the clamp fixing seat are set on a fixed object, the external fixed rod is installed on the fixed base and the clamp fixing seat to achieve fixation, the internal telescopic rod is set in the external fixed rod and can be telescopically moved, the locking sleeve is set at the end of the external fixed rod, and has a movable buckle on it for adjusting the locking progress of the locking sleeve. When locked, the internal telescopic rod is clamped and fixed by the external fixed rod. When unlocked, the internal telescopic rod can be manually extended and retracted to adjust the extension height of the internal telescopic rod.

Images