A method and device for obtaining three-dimensional wind field based on a single phased array weather radar

Abstract

The present invention discloses a method and device for obtaining a three-dimensional wind field based on a single phased array weather radar. The method uses a phased array weather radar to scan cloud and rain targets in the atmosphere, reads the received echo data according to the range gate, and calculates the spectrum of each range gate, and forms a beam by weighted summation of the spectrum including the phase offset to perform beam control; the formed beam is subjected to spectral moment analysis by fast Fourier transform to calculate the radial velocity V of the cloud and rain target; two receiving sub-array beams arranged horizontally and vertically are formed by weighted summation of the spectrum; the cross-correlation function and the autocorrelation function of the two receiving sub-array beams arranged horizontally and the two receiving sub-array beams arranged vertically are calculated by fast Fourier transform, and then the tangential velocity component in the horizontal direction and the tangential velocity component in the vertical direction are calculated, so as to obtain three-dimensional wind field information. The present invention has the advantages of simple equipment, low implementation cost and superior performance.

Description

Technical Field

[0001] The present invention relates to the technical field of three-dimensional wind field acquisition, and in particular to a method and device for acquiring a three-dimensional wind field based on a single phased array weather radar. Background Art

[0002] With the continuous application of weather radar, the wind field information provided by weather radar has attracted more and more attention. However, since a single radar only obtains the radial component of velocity, in order to accurately understand the three-dimensional wind field of the atmosphere, it is also necessary to know the tangential velocity and vertical velocity of the wind field. Therefore, how to obtain two-dimensional or three-dimensional wind fields has become a problem that people have always paid attention to.

[0003] The invention patent with the publication number CN111505596A proposes a three-dimensional wind field inversion method based on non-uniform sampling modified VAD technology. This is a method based on a single parabolic weather radar. It is necessary to assume the spatial distribution model of the wind field in the detection horizontal plane and perform inversion calculations according to this model. The actual weather conditions are complex and changeable, and it is difficult to describe the actual situation with one or several wind field spatial distribution models. Therefore, the effect of this method is difficult to meet the requirements of real-time use.

[0004] The invention patent with the publication number CN108107434A proposes a regional three-dimensional wind field jigsaw method based on dual Doppler radar inversion. This method does not require the assumption of a wind field spatial distribution model, but because two Doppler radars are used for inversion, the two radars need to be synchronized in time and space, and intensity correction is also required to transmit data from one radar to another to generate a real-time three-dimensional wind field, which is technically complex. In addition to the high cost of using two Doppler radar systems for observation, the limitation is that the two radars can only measure the three-dimensional wind field in the overlapping area of ​​the beam scan. If the distance between the two radars is not far enough, the horizontal component of the distant wind field cannot be directly measured. These factors limit the site selection of the radar.

[0005] Phased array weather radar uses multi-beam simultaneous detection, which greatly improves the speed of full airspace scanning compared to traditional weather radar. Traditional weather radar takes about 6 minutes to complete a full airspace scan, while phased array weather radar can complete it in less than 1 minute. Therefore, phased array weather radar has become the development direction of the next generation of weather radar. The unique technical features of phased array weather radar provide a new method for a single radar to obtain three-dimensional wind fields. Summary of the invention

[0006] The purpose of the present invention is to provide a method and device for obtaining a three-dimensional wind field based on a single phased array weather radar in view of the deficiencies in the prior art.

[0007] To achieve the above objectives, in a first aspect, the present invention provides a method for acquiring a three-dimensional wind field based on a single phased array weather radar, comprising:

[0008] The antenna array of the phased array weather radar is used to transmit electromagnetic waves to scan cloud and rain targets in the atmosphere, and receive echo data returned from the cloud and rain targets, wherein the antenna array includes a plurality of array elements;

[0009] Read the received echo data according to the range gate, calculate the spectrum of each range gate, and form a beam by weighted summation of the spectrum including phase offset to perform beam control;

[0010] The formed beam is analyzed by fast Fourier transform to calculate the radial velocity V of the cloud and rain target.

[0011] Based on the division of the multiple array elements, the formed beam is processed to form two receiving sub-array beams which are arranged horizontally and vertically respectively, and the origin positions of the two receiving sub-array beams are different;

[0012] Fast Fourier transform is used to calculate the cross-correlation function and autocorrelation function of the two receiving sub-arrays arranged horizontally and the two receiving sub-arrays arranged vertically respectively.

[0013] According to the parameters τ′, τ on the cross-correlation function and autocorrelation function of the horizontally arranged receiving sub-array beams and the cross-correlation function and autocorrelation function of the vertically arranged receiving sub-array beams x The horizontal tangential velocity component and the vertical tangential velocity component are calculated respectively, where τ′ is the cross-correlation delay time corresponding to the maximum value of the cross-correlation function, τ x is the autocorrelation delay time corresponding to when the autocorrelation function drops to the maximum value of the cross-correlation function;

[0014] According to each range gate, the radial velocity V, the horizontal tangential velocity component, and the vertical tangential velocity component of the cloud and rain target are fused to obtain three-dimensional wind field information;

[0015] Generate and display a three-dimensional wind field map based on the three-dimensional wind field information.

[0016] Furthermore, the cross-correlation function of the two receiving sub-array beams is expressed as:

[0017] |ρ 12 (τ)|=αexp[-4(Vτ-D cosθ / 2) 2 / (L cosθ) 2 ]

[0018] Among them, |ρ 12(τ)| is the cross-correlation function of the two sub-receiving sub-array beams, α is the amplitude modulation coefficient of the phased array weather radar, exp[·] is an exponential function with the natural constant e as the base, τ is the cross-correlation delay time of the cross-correlation function, D is the distance between the origins of the two sub-receiving sub-array beams, θ is the pointing angle of the formed beam, and L is the size of the receiving subarray corresponding to each receiving subarray beam in the arrangement direction.

[0019] Furthermore, the tangential velocity component is calculated as follows:

[0020]

[0021] Where v is the calculated tangential velocity component.

[0022] Furthermore, the two receiving sub-arrays are receiving sub-arrays composed of completely separate different array elements or receiving sub-arrays with overlapping array elements.

[0023] In a second aspect, the present invention provides a device for acquiring a three-dimensional wind field based on a single phased array weather radar, comprising:

[0024] The antenna array includes a plurality of array elements, which are used to transmit electromagnetic waves to scan cloud and rain targets in the atmosphere and receive echo data returned from the cloud and rain targets;

[0025] A digital beam forming unit, which reads the received echo data according to the range gate and calculates the spectrum of each range gate, and forms a beam by summing the spectrum including the phase offset to perform beam control;

[0026] A signal processing unit is used to perform spectral moment analysis on the formed beam by using fast Fourier transform to calculate the radial velocity V of the cloud and rain target; the signal processing unit forms two receiving sub-array beams arranged horizontally and vertically respectively by weighted summation of the spectrum based on the division of multiple array elements, and the origin positions of the two receiving sub-array beams are different; and the fast Fourier transform is used to calculate the cross-correlation function and autocorrelation function of the two horizontally arranged sub-array beams and the two vertically arranged sub-array beams; according to the cross-correlation function and autocorrelation function of the horizontally arranged receiving sub-array beams and the cross-correlation function and autocorrelation function of the vertically arranged receiving sub-array beams, the parameters τ′ and τ x The horizontal tangential velocity component and the vertical tangential velocity component are calculated respectively, where τ′ is the cross-correlation delay time corresponding to the maximum value of the cross-correlation function, τ x is the autocorrelation delay time corresponding to when the autocorrelation function drops to the maximum value of the cross-correlation function;

[0027] The data processing unit fuses the radial velocity V, the tangential velocity component in the horizontal direction, and the tangential velocity component in the vertical direction of the cloud and rain target according to each range gate to obtain three-dimensional wind field information;

[0028] The display unit is used to generate and display a three-dimensional wind field map according to the three-dimensional wind field information.

[0029] Furthermore, the cross-correlation function of the two receiving sub-array beams is expressed as:

[0030] |ρ 12 (τ)|=αexp[-4(Vτ-D cosθ / 2) 2 / (Lcosθ) 2 ]

[0031] Among them, |ρ 12 (τ)| is the cross-correlation function of the two sub-receiving sub-array beams, α is the amplitude modulation coefficient of the phased array weather radar, exp[·] is an exponential function with the natural constant e as the base, τ is the cross-correlation delay time of the cross-correlation function, D is the distance between the origins of the two sub-receiving sub-array beams, θ is the pointing angle of the formed beam, and L is the size of the receiving subarray corresponding to each receiving subarray beam in the arrangement direction.

[0032] Furthermore, the tangential velocity component is calculated as follows:

[0033]

[0034] Where v is the calculated tangential velocity component.

[0035] Furthermore, the two receiving sub-arrays are receiving sub-arrays composed of completely separate different array elements or receiving sub-arrays with overlapping array elements.

[0036] Beneficial effects: The present invention can obtain the tangential velocity of cloud and rain targets relative to the radar through spectrum calculation, thereby obtaining a three-dimensional wind field; compared with the prior art that relies on weather radar to obtain radial velocity and then inverts the three-dimensional wind field through VAD technology according to a certain mathematical model, the three-dimensional wind field obtained by the present invention is more accurate; compared with the use of two or more Doppler radars to measure the three-dimensional wind field, the present invention has the advantages of simple equipment, low implementation cost and superior performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a flowchart of a method for obtaining a three-dimensional wind field based on a single phased array weather radar;

[0038] Figure 2 is a schematic diagram of the division structure of the horizontally arranged receiving sub-array;

[0039] Figure 3It is a schematic diagram of the division structure of the vertically arranged receiving sub-array;

[0040] Figure 4 This is a schematic diagram of the principle of measuring tangential wind by phased array weather radar;

[0041] Figure 5 τ′ and τ are obtained based on the autocorrelation function and the cross-correlation function. x Schematic diagram of

[0042] Figure 6 It is a principle block diagram of a device for acquiring three-dimensional wind fields based on a single phased array weather radar. DETAILED DESCRIPTION

[0043] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. The embodiments are implemented based on the technical solution of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0044] like Figures 1 to 4 As shown, an embodiment of the present invention provides a method for acquiring a three-dimensional wind field based on a single phased array weather radar, comprising:

[0045] The antenna array of the phased array weather radar emits electromagnetic waves to scan the cloud and rain targets in the atmosphere and receives the echo data returned from the cloud and rain targets. The antenna array includes multiple array elements. The phased array weather radar can be a pulsed monostatic radar in the S, C, and X bands commonly used in weather radars, or it can operate in other frequency bands.

[0046] The received echo data is read by range gate and the spectrum of each range gate is calculated. A beam is formed by summing the spectrum including the phase offset for beam steering.

[0047] The formed beam is analyzed by fast Fourier transform to calculate the radial velocity V of the cloud and rain target. Specifically, the beam data read above needs to be input into the processing software to complete signal accumulation and phasing, and then the signal time series of each receiver is Fourier transformed. Then the obtained spectrum is analyzed by spectral moment to obtain the power spectrum and measure the radial velocity component.

[0048] Based on the division of multiple array elements, two receiving sub-array beams arranged horizontally and vertically are formed by weighted summing of the spectrum, and the origin positions of the two receiving sub-array beams are different. Multiple array elements are divided twice, and each division forms two receiving sub-arrays. Each receiving sub-array includes multiple array elements, and the receiving sub-arrays formed by the two divisions are arranged horizontally and vertically. For details, please refer to Figure 2 , which illustrates the receiving sub-array division structure when arranged horizontally, where Figure 2 (a) is a schematic diagram of the case where array elements overlap. Figure 2(b) is a schematic diagram when the array elements do not overlap. In actual use, the selection of the receiving subarray is variable, and a receiving subarray can be composed of array elements in any position and number. The beam origins of the two receiving subarrays used to calculate and process the tangential velocity must not be in the same position. Figure 2 (a) with Figure 2 (b) Compared with the conventional radar, the spacing between the beam origins of the receiving subarrays is different, and the gain of the receiving subarrays is also different. The specific selection method needs to be determined based on the actual usage of the radar installation site. Figure 3 The receiving sub-array division structure when arranged vertically is shown. The specific division method is the same as Figure 2 The above two receiving subarrays can be receiving subarrays composed of completely separate different array elements, or they can be receiving subarrays with overlapping array elements. Each receiving subarray has its own digital receiver, and can also form a receiving subarray beam in the radar's digital beamforming module (DBF). The origins of each receiving subarray beam are spaced apart in space. If there is no spacing, the cross-correlation function cannot be calculated. It is preferred to use DBF to form the receiving subarray beam. DBF can be used to control the direction of the receiving subarray beam, which can be more flexible.

[0049] Fast Fourier transform is used to calculate the cross-correlation function and autocorrelation function of the two horizontally arranged sub-arrays and the two vertically arranged receiving sub-array beams. Figure 4 ,in, Figure 4 (a) shows the transmit beam. The transmit beam is transmitted with the full antenna aperture. The transmit beam is wide and covers the range of the receive beam of the receive subarray. This will give the strongest signal-to-noise ratio and is more conducive to subsequent processing. Of course, it is also possible not to use full-aperture transmission, as long as the transmit beam width can cover the receive beam. Figure 4(b) shows two receiving subarray beams, which are synthesized by receiving subarrays. When the cloud and rain target moves relative to the radar, it passes through the transmitting beam and the receiving beam. The echo signal obtained is analyzed by spectral moment, and the autocorrelation function and cross-correlation function are calculated. According to the characteristics of cloud and rain targets in the atmosphere, the signal received by the phased array weather radar is mainly Rayleigh scattering of cloud and rain targets, and also contains Bragg scattering. During the correlation time of the target, it can be assumed that the target echo signal received by the receiving subarray beam satisfies the stationary random process in all directions, then there is a Doppler component in the radial direction of the beam, which can be obtained using the FFT algorithm. The tangential correlation length of the signal is approximately the lateral size of the transmitting array of the phased array antenna. According to the reciprocity principle, the correlation length of the signal received by the receiving antenna is the lateral size of the receiving antenna. Assuming that the distance between the origins of the two receiving beams is D, the backscatter of the cloud and rain target will translate through the receiving antenna at a speed of 2v, where v is the tangential speed in the scattering area of ​​the cloud and rain target. If the peak value of the cross-correlation function of the signal detected by two antennas with a distance D between the beam origins remains unchanged, the time delay is D / 2v. Therefore, the tangential velocity can be obtained by measuring the peak delay. In order to avoid the peak delay being less than D / 2v, the autocorrelation function must be used for correction.

[0050] If the radiation pattern of the receiving antenna is Gaussian, the radiation field can be considered unchanged. When the cloud and rain targets are evenly distributed in the radar resolution area, the cross-correlation function of the two receiving sub-array beams is expressed as:

[0051] |ρ 12 (τ)|=αexp[-4(Vτ-D cosθ / 2) 2 / (L cosθ) 2 ]

[0052] Among them, |ρ 12 (τ)| is the cross-correlation function of the two sub-receiving sub-array beams, α is the amplitude modulation coefficient of the phased array weather radar, exp[·] is an exponential function with the natural constant e as the base, τ is the cross-correlation delay time of the cross-correlation function, D is the distance between the origins of the two sub-receiving sub-array beams, θ is the pointing angle of the formed beam, and L is the size of the receiving sub-array corresponding to each receiving sub-array beam in the arrangement direction, that is, when the receiving sub-arrays are arranged horizontally, the size of the receiving sub-array corresponding to each receiving sub-array beam in the horizontal direction, and when the receiving sub-arrays are arranged vertically, the size of the receiving sub-array corresponding to each receiving sub-array beam in the vertical direction. In addition, when D in the above formula is set to 0, the above formula is the autocorrelation function of the two receiving sub-array beams.

[0053] According to the parameters τ′, τ on the cross-correlation function and autocorrelation function of the horizontally arranged receiving sub-array beams and the cross-correlation function and autocorrelation function of the vertically arranged receiving sub-array beams xThe tangential velocity component in the horizontal direction and the tangential velocity component in the vertical direction are calculated respectively, where τ′ is the cross-correlation delay time corresponding to the maximum value of the cross-correlation function, that is, the value of τ when the cross-correlation function is the maximum value, τ x is the autocorrelation delay time corresponding to when the autocorrelation function drops to the maximum value of the cross-correlation function, that is, the value of τ when the autocorrelation function drops to the maximum value of the cross-correlation function. For details, please refer to Figure 5 , Figure 5 The diagram shows how to obtain τ′ and τ based on the autocorrelation function and the cross-correlation function. x , where the x-axis represents time, and the y-axis represents the values ​​of the autocorrelation function and the cross-correlation function. When calculating the autocorrelation function, it is only necessary to calculate the autocorrelation function of one receiving subarray beam. It is preferred to calculate the receiving subarray beam that is obtained first. Taking the two receiving subarrays arranged horizontally formed by division as an example, if the cloud and rain target moves from left to right, the receiving subarray on the left receives the returned echo data first, and thus obtains the receiving subarray beam first. Then, τ is calculated based on the autocorrelation function. x That is, when both receiving sub-arrays receive echo data, τ′ is calculated based on the cross-correlation function.

[0054] If the cloud and rain target changes with time, the maximum value of the cross-correlation function decreases, and the position of the maximum correlation will be biased towards zero delay. Although the basic form of the above formula still exists, the estimate will be too large. In this case, the autocorrelation function can be used to correct the random changes. In order to achieve velocity estimation correction, the tangential velocity component can be calculated as follows:

[0055]

[0056] Where v is the calculated tangential velocity component. If random variations can be ignored, then τ x = 0, τ′ = 1. If the τ′ value decreases as the delay value increases, after exceeding the threshold, it should return to zero speed instead of a very large speed.

[0057] According to each range gate, the radial velocity V, the tangential velocity component in the horizontal direction, and the tangential velocity component in the vertical direction of the cloud and rain target are fused to obtain three-dimensional wind field information.

[0058] A three-dimensional wind field map is generated and displayed according to the three-dimensional wind field information. In addition, the storage and transmission of the three-dimensional wind field information can be controlled.

[0059] Combination Figures 1 to 6Based on the above embodiments, those skilled in the art can easily understand that the present invention also provides a device for acquiring a three-dimensional wind field based on a single phased array weather radar, including an antenna array surface 1, a digital beam forming unit 2, a signal processing unit 3, a data processing unit 4, a display unit 5, a radar control unit 6, a frequency synthesizer 7, a subarray amplification unit 8, a servo mechanism 9 and an antenna base 10, etc.

[0060] Among them, the antenna array 1 includes a plurality of array elements for transmitting electromagnetic waves to scan cloud and rain targets in the atmosphere and receiving echo data returned from cloud and rain targets. The phased array weather radar can be a pulsed single-base radar in the S, C, and X bands commonly used in weather radars, or it can operate in other frequency bands. When the radar is transmitting, the radar control unit 6 generates a control signal and outputs it to the frequency synthesizer 7. The frequency synthesizer 7 generates a radio frequency signal and feeds it to the subarray amplifier unit 8. The subarray amplifier unit 8 then amplifies the signal and feeds it to each array element on the antenna subarray to form a transmitting beam. The servo mechanism 9 is used to realize the detection direction control, and the antenna base 10 is used to install the antenna array 1.

[0061] The digital beam forming unit 2 is used to read the received echo data according to the range gate, calculate the spectrum of each range gate, and form a beam by summing the spectrum including the phase shift to perform beam control.

[0062] The signal processing unit 3 is used to perform spectral moment analysis on the formed beam using fast Fourier transform to calculate the radial velocity V of the cloud and rain target. Specifically, the beam data read above needs to be input into the processing software to complete signal accumulation and phasing, and then the signal time series of each receiver is Fourier transformed. Then, the obtained spectrum is analyzed by spectral moment to obtain the power spectrum and measure the radial velocity component.

[0063] The signal processing unit 3 is further used to form two receiving sub-array beams arranged horizontally and vertically respectively by weighted summing of the spectrum based on the division of the multiple array elements, and the origin positions of the two receiving sub-array beams are different. The multiple array elements are divided twice, and each division forms two receiving sub-arrays, each sub-array includes multiple array elements, and the receiving sub-arrays formed by the two divisions are arranged horizontally and vertically respectively. For details, please refer to Figure 2 , which illustrates the receiving sub-array division structure when arranged horizontally, where Figure 2 (a) is a schematic diagram of the case where array elements overlap. Figure 2 (b) is a schematic diagram when the array elements do not overlap. In actual use, the selection of the receiving subarray is variable, and a receiving subarray can be composed of array elements in any position and number. The beam origins of the two receiving subarrays used to calculate and process the tangential velocity must not be in the same position. Figure 2 (a) with Figure 2(b) Compared with the conventional radar, the spacing between the beam origins of the receiving subarrays is different, and the gain of the receiving subarrays is also different. The specific selection method needs to be determined based on the actual usage of the radar installation site. Figure 3 The receiving sub-array division structure when arranged vertically is shown. The specific division method is the same as Figure 2 The above two receiving subarrays can be receiving subarrays composed of completely separate different array elements, or they can be receiving subarrays with overlapping array elements. Each receiving subarray has its own digital receiver, and can also form a receiving subarray beam in the radar's digital beamforming module (DBF). The origins of each receiving subarray beam are spaced apart in space. If there is no spacing, the cross-correlation function cannot be calculated. It is preferred to use DBF to form the receiving subarray beam. DBF can be used to control the direction of the receiving subarray beam, which can be more flexible.

[0064] The signal processing unit 3 also uses fast Fourier transform to calculate the cross-correlation function and autocorrelation function of the two horizontally arranged sub-arrays and the two vertically arranged receiving sub-array beams. Figure 4 ,in, Figure 4 (a) shows the transmit beam. The transmit beam is transmitted with the full antenna aperture. The transmit beam is wide and covers the range of the receive beam of the receive subarray. This will give the strongest signal-to-noise ratio and is more conducive to subsequent processing. Of course, it is also possible not to use full-aperture transmission, as long as the transmit beam width can cover the receive beam. Figure 4 (b) shows two receiving subarray beams, which are synthesized by receiving subarrays. When the cloud and rain target moves relative to the radar, it passes through the transmitting beam and the receiving beam. The echo signal obtained is analyzed by spectral moment, and the autocorrelation function and cross-correlation function are calculated. According to the characteristics of cloud and rain targets in the atmosphere, the signal received by the phased array weather radar is mainly Rayleigh scattering of cloud and rain targets, and also contains Bragg scattering. During the correlation time of the target, it can be assumed that the target echo signal received by the receiving subarray beam satisfies the stationary random process in all directions, then there is a Doppler component in the radial direction of the beam, which can be obtained using the FFT algorithm. The tangential correlation length of the signal is approximately the lateral size of the transmitting array of the phased array antenna. According to the reciprocity principle, the correlation length of the signal received by the receiving antenna is the lateral size of the receiving antenna. Assuming that the distance between the origins of the two receiving beams is D, the backscatter of the cloud and rain target will translate through the receiving antenna at a speed of 2v, where v is the tangential speed in the scattering area of ​​the cloud and rain target. If the peak value of the cross-correlation function of the signal detected by two antennas with a distance D between the beam origins remains unchanged, the time delay is D / 2v. Therefore, the tangential velocity can be obtained by measuring the peak delay. In order to avoid the peak delay being less than D / 2v, the autocorrelation function must be used for correction.

[0065] If the radiation pattern of the receiving antenna is Gaussian, the radiation field can be considered unchanged. When the cloud and rain targets are evenly distributed in the radar resolution area, the cross-correlation function of the two receiving sub-array beams is expressed as:

[0066] |ρ 12 (τ)I=αexp[-4(Vτ-Dcosθ / 2) 2 / (Lcosθ) 2 ]

[0067] Among them, |ρ 12 (τ)| is the cross-correlation function of the two sub-receiving sub-array beams, α is the amplitude modulation coefficient of the phased array weather radar, exp[·] is an exponential function with the natural constant e as the base, τ is the cross-correlation delay time of the cross-correlation function, D is the distance between the origins of the two sub-receiving sub-array beams, θ is the pointing angle of the formed beam, and L is the size of the receiving sub-array corresponding to each receiving sub-array beam in the arrangement direction, that is, when the receiving sub-arrays are arranged horizontally, the size of the receiving sub-array corresponding to each receiving sub-array beam in the horizontal direction, and when the receiving sub-arrays are arranged vertically, the size of the receiving sub-array corresponding to each receiving sub-array beam in the vertical direction. In addition, when D in the above formula is set to 0, the above formula is the autocorrelation function of the two receiving sub-array beams.

[0068] According to the parameters τ′, τ on the cross-correlation function and autocorrelation function of the horizontally arranged receiving sub-array beams and the cross-correlation function and autocorrelation function of the vertically arranged receiving sub-array beams x The tangential velocity component in the horizontal direction and the tangential velocity component in the vertical direction are calculated respectively, where τ′ is the cross-correlation delay time corresponding to the maximum value of the cross-correlation function, that is, the value of τ when the cross-correlation function is the maximum value, τ x is the autocorrelation delay time corresponding to when the autocorrelation function drops to the maximum value of the cross-correlation function, that is, the value of τ when the autocorrelation function drops to the maximum value of the cross-correlation function. For details, please refer to Figure 5 , Figure 5 The diagram shows how to obtain τ′ and τ based on the autocorrelation function and the cross-correlation function. x , where the x-axis represents time, and the y-axis represents the values ​​of the autocorrelation function and the cross-correlation function. When calculating the autocorrelation function, it is only necessary to calculate the autocorrelation function of one receiving subarray beam. It is preferred to calculate the receiving subarray beam that is obtained first. Taking the two receiving subarrays arranged horizontally formed by division as an example, if the cloud and rain target moves from left to right, the receiving subarray on the left receives the returned echo data first, and thus obtains the receiving subarray beam first. Then, τ is calculated based on the autocorrelation function. x That is, when both receiving sub-arrays receive echo data, τ′ is calculated based on the cross-correlation function.

[0069] If the cloud and rain target changes with time, the maximum value of the cross-correlation function decreases, and the position of the maximum correlation will be biased towards zero delay. Although the basic form of the above formula still exists, the estimate will be too large. In this case, the autocorrelation function can be used to correct the random changes. In order to achieve velocity estimation correction, the tangential velocity component can be calculated as follows:

[0070]

[0071] Where v is the calculated tangential velocity component. If random variations can be ignored, then τ x = 0, τ′ = 1. If the τ′ value decreases as the delay value increases, after exceeding the threshold, it should return to zero speed instead of a very large speed.

[0072] The data processing unit 4 fuses the radial velocity V, the tangential velocity component in the horizontal direction, and the tangential velocity component in the vertical direction of the cloud and rain target according to each range gate to obtain three-dimensional wind field information.

[0073] The display unit 5 is used to generate and display a three-dimensional wind field map according to the three-dimensional wind field information. In addition, the three-dimensional wind field information can be controlled to be stored and transmitted.

[0074] The above is only a preferred embodiment of the present invention. It should be noted that for ordinary technicians in this technical field, other parts not specifically described belong to the prior art or common knowledge. Several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention.

Claims

1. A method for acquiring a three-dimensional wind field based on a single phased array weather radar, characterized in that: include: The antenna array of the phased array weather radar is used to transmit electromagnetic waves to scan cloud and rain targets in the atmosphere, and receive echo data returned from the cloud and rain targets, wherein the antenna array includes a plurality of array elements; Read the received echo data according to the range gate, calculate the spectrum of each range gate, and form a beam by weighted summation of the spectrum including phase offset to perform beam control; The formed beam is analyzed by fast Fourier transform to calculate the radial velocity V of the cloud and rain target. Based on the division of multiple array elements, two receiving sub-array beams arranged horizontally and vertically are formed respectively by weighted summing of the spectrum, and the origin positions of the two receiving sub-array beams are different; Fast Fourier transform is used to calculate the cross-correlation function and autocorrelation function of the two receiving sub-arrays arranged horizontally and the two receiving sub-arrays arranged vertically respectively; According to the parameters τ′, τ on the cross-correlation function and autocorrelation function of the horizontally arranged receiving sub-array beams and the cross-correlation function and autocorrelation function of the vertically arranged receiving sub-array beams x The horizontal tangential velocity component and the vertical tangential velocity component are calculated respectively, where τ′ is the cross-correlation delay time corresponding to the maximum value of the cross-correlation function, τ x is the autocorrelation delay time corresponding to when the autocorrelation function drops to the maximum value of the cross-correlation function; According to each range gate, the radial velocity V, the horizontal tangential velocity component, and the vertical tangential velocity component of the cloud and rain target are fused to obtain three-dimensional wind field information; Generate and display a three-dimensional wind field map based on the three-dimensional wind field information.

2. The method for acquiring a three-dimensional wind field based on a single phased array weather radar according to claim 1, characterized in that: The cross-correlation function of the two receiving sub-array beams is expressed as: |r 12 (τ)|=αexp[-4(Vτ-D coSθ / 2) 2 / (L cosθ) 2 ] Among them, |ρ 12 (τ)| is the cross-correlation function of the two sub-receiving sub-array beams, α is the amplitude modulation coefficient of the phased array weather radar, exp[·] is an exponential function with the natural constant e as the base, τ is the cross-correlation delay time of the cross-correlation function, D is the distance between the origins of the two sub-receiving sub-array beams, θ is the pointing angle of the formed beam, and L is the size of the receiving subarray corresponding to each receiving subarray beam in the arrangement direction.

3. The method for acquiring a three-dimensional wind field based on a single phased array weather radar according to claim 2, characterized in that: The tangential velocity component is calculated as follows: Where v is the calculated tangential velocity component.

4. The method for acquiring a three-dimensional wind field based on a single phased array weather radar according to claim 1, characterized in that: The two receiving sub-arrays are receiving sub-arrays composed of completely separate different array elements or receiving sub-arrays with overlapping array elements.

5. A device for acquiring a three-dimensional wind field based on a single phased array weather radar, characterized in that: include: The antenna array includes a plurality of array elements, which are used to transmit electromagnetic waves to scan cloud and rain targets in the atmosphere and receive echo data returned from the cloud and rain targets; A digital beam forming unit reads received echo data according to the range gate, calculates the spectrum of each range gate, and forms a beam by weighted summation of the spectrum including phase offset to perform beam control; A signal processing unit is used to perform spectral moment analysis on the formed beam using fast Fourier transform to calculate the radial velocity V of the cloud and rain target; The signal processing unit forms two receiving sub-array beams arranged horizontally and vertically respectively by weighted summing of spectrum based on the division of multiple array elements, and the origin positions of the two receiving sub-array beams are different; and adopts fast Fourier transform to calculate the cross-correlation function and autocorrelation function of the two horizontally arranged sub-array beams and the two vertically arranged sub-array beams; according to the cross-correlation function and autocorrelation function of the horizontally arranged receiving sub-array beams and the cross-correlation function and autocorrelation function of the vertically arranged receiving sub-array beams, the parameters τ′ and τ x The horizontal tangential velocity component and the vertical tangential velocity component are calculated respectively, where τ′ is the cross-correlation delay time corresponding to the maximum value of the cross-correlation function, τ x is the autocorrelation delay time corresponding to when the autocorrelation function drops to the maximum value of the cross-correlation function; The data processing unit fuses the radial velocity V, the tangential velocity component in the horizontal direction, and the tangential velocity component in the vertical direction of the cloud and rain target according to each range gate to obtain three-dimensional wind field information; The display unit is used to generate and display a three-dimensional wind field map according to the three-dimensional wind field information.

6. The device for acquiring a three-dimensional wind field based on a single phased array weather radar according to claim 5, characterized in that: The cross-correlation function of the two receiving sub-array beams is expressed as: |r 12 (τ)|=αexp[-4(Vτ-D cosθ / 2) 2 / (L cosθ) 2 ] Among them, |ρ 12 (τ)| is the cross-correlation function of the two sub-receiving sub-array beams, α is the amplitude modulation coefficient of the phased array weather radar, exp[·] is an exponential function with the natural constant e as the base, τ is the cross-correlation delay time of the cross-correlation function, D is the distance between the origins of the two sub-receiving sub-array beams, θ is the pointing angle of the formed beam, and L is the size of the receiving subarray corresponding to each receiving subarray beam in the arrangement direction.

7. The device for acquiring a three-dimensional wind field based on a single phased array weather radar according to claim 6, characterized in that: The tangential velocity component is calculated as follows: Where v is the calculated tangential velocity component.

8. The device for acquiring a three-dimensional wind field based on a single phased array weather radar according to claim 5, characterized in that: The two receiving sub-arrays are receiving sub-arrays composed of completely separate different array elements or receiving sub-arrays with overlapping array elements.

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