CN-122017758-A - Method for realizing dual-polarization phased array weather radar target simulation by utilizing digital receiver

CN122017758ACN 122017758 ACN122017758 ACN 122017758ACN-122017758-A

Abstract

The invention discloses a method for realizing dual-polarization phased array weather radar target simulation by utilizing a digital receiver, and relates to the technical field of radar signal processing. According to the method for realizing double-polarization phased array weather radar target simulation by using the digital receiver, a weather target micro-physical parameter model is established, abundant FPGA resources in the phased array radar digital receiver are combined, a technology similar to direct digital frequency synthesis (DDS) is utilized to generate a high-fidelity digital intermediate-frequency echo signal, and dynamic target simulation is realized in an active array digital receiver of the phased array radar. The controllable and repeatable simulation of various weather phenomena (rain, snow, hail and the like) is realized in a laboratory environment. According to the invention, under the condition of not depending on external hardware, the echo characteristics of weather targets (such as precipitation particles) are simulated, including parameters such as distance, speed, amplitude, double-polarization parameter physical quantity and the like, and the debugging, performance verification and algorithm test of the radar system are effectively supported.

Inventors

HU XINYUE
QIN JIANG
LEI LIANFA
LU JIANPING
ZHANG XING
QIN ZHENGYANG
LV ZHILIN
MU TAO

Assignees

北方天穹信息技术（西安）有限公司

Dates

Publication Date: 20260512
Application Date: 20260203

Claims (7)

1. The method for realizing the dual-polarization phased array weather radar target simulation by using the digital receiver is characterized by comprising the following steps of: s1, simulating a non-spherical precipitation particle spectrum, namely describing a raindrop spectrum by adopting gamma distribution, establishing a micro-physical model of precipitation particles, and setting distribution parameters of the raindrop spectrum according to different precipitation types; S2, calculating a scattering Matrix, namely calculating the scattering Matrix of the non-spherical particles by adopting a T-Matrix method, taking the axial ratio, dielectric constant and spatial orientation of the particles into consideration, and establishing a scattering parameter database; s3, calculating double polarization parameters, namely calculating the double polarization parameters which can be observed by the radar based on the scattering matrix, wherein the double polarization parameters comprise horizontal reflectivity factors Vertical reflectance factor Differential reflectance Differential propagation phase shift rate Coefficient of correlation ; S4, setting environmental parameters, namely configuring environmental parameters of temperature, pressure and humidity, establishing an atmospheric refractive index model, and simulating signal propagation characteristics in a real atmospheric environment; s5, configuring simulation parameters, namely setting control parameters of a digital frequency synthesis technology based on the dual-polarization parameters and the environment parameters, wherein the control parameters comprise a phase accumulator bit width, a frequency control word and a phase control word so as to simulate the characteristics of a target echo signal; s6, simulating phased array beam formation, namely calculating the wave path difference among array elements caused by a target azimuth angle theta and a pitch angle phi, generating a phase compensation term, and simulating a beam scanning effect; And S7, signal injection and processing, namely generating a digital intermediate frequency analog signal according to the control parameter by utilizing logic resources in the phased array radar digital receiver, injecting the digital intermediate frequency analog signal into each array element digital signal processing channel corresponding to the DBF receiving array, and performing subsequent signal processing and verification after the digital intermediate frequency analog signal is overlapped with background data.
2. The method according to claim 1, wherein the gamma distribution in step S1 is expressed as: Wherein, the Is the unit volume and the unit diameter interval To the point of ) The number of the raindrops in the water tank, As a parameter of the concentration of the liquid, Is a shape parameter of the spectrum and, Is the median diameter of the drip spectrum, Is the equivalent sphere diameter of an ellipsoidal particle.
3. The method according to claim 1, wherein the T-Matrix method in step S2 includes calculating scattering Matrix elements based on the particle axis ratio and the dielectric constant, and storing scattering characteristic data under different temperature and humidity conditions in a database.
4. The method according to claim 1, wherein the calculating of the dual polarization parameters in step S3 comprises: calculation of horizontal reflectance factor from horizontally and vertically polarized backscattering cross sections And a vertical reflectance factor ; By the formula Calculating a differential reflectivity factor; By the formula Calculating a differential propagation phase shift rate, wherein 、 Propagation constants for horizontal and vertical polarization; Calculating correlation coefficients based on cross-correlation properties of horizontal and vertical polarization scatter amplitudes 。
5. The method according to claim 1, wherein the specific roles of the control parameters in step S5 are: the frequency control word is used for simulating Doppler frequency shift and distance information based on echo time delay of a target; the phase control word is used for simulating comprehensive phase change caused by inter-array element wave path difference, propagation path phase and double polarization scattering phase difference; The amplitude control word is used to simulate the echo power determined by the radar equation The resulting amplitude differences.
6. The method of claim 1, wherein the signal processing in step S7 includes processing the intermediate frequency signal with a digital down conversion module and performing beam forming using DBF techniques to achieve target detection in the context of astronomical noise, thermal noise, weather and clutter.
7. A system for implementing the method of any one of claims 1-6, comprising: The micro-physical modeling module is used for executing the steps S1 and S2 and establishing a precipitation particle model and a scattering parameter database; The parameter calculation module is used for executing the steps S3 and S4 and calculating the radar double polarization parameters and the environment propagation characteristics; the digital signal generation module is integrated in a digital receiver FPGA of the phased array radar and is used for executing the steps S5 and S6, and comprises a phase accumulator, a sine lookup table and control logic, and a DDS technology is utilized to generate a digital intermediate frequency signal with specific amplitude, phase and frequency characteristics; And the signal injection and processing module is used for executing the step S7, injecting the analog signals into the digital signal processing link, and completing beam forming and radar function verification.

Description

Method for realizing dual-polarization phased array weather radar target simulation by utilizing digital receiver Technical Field The invention relates to the technical field of radar signal processing, in particular to a method for realizing double-polarization phased array weather radar target simulation by using a digital receiver. Background The phased array weather radar is used as a new generation of weather observation equipment, and realizes the rapid and high-resolution detection of a precipitation system through electronic scanning and DBF technology. However, in the development and testing process, the conventional debugging method is severely dependent on the outfield actual measurement test and the natural weather conditions, and has a plurality of limitations. The methods generally need to perform data acquisition and performance verification in a real meteorological environment, so that the debugging efficiency is low, the cost is high, and the consistency and the repeatability of the test result are difficult to ensure. The traditional debugging is required to be carried out when specific weather phenomena (such as rainfall, snowfall and wind fields) occur, and is greatly restricted by natural conditions. For example, parameters such as rainfall intensity, particle distribution, wind shear and the like cannot be generated as required, so that a test window is limited, and a development period is prolonged. In actual measurement, radar performance verification needs to wait for proper weather, which may be delayed for months, and project progress is affected. And natural weather events have randomness and dynamics, and the same meteorological scene (such as the microphysical characteristics of thunderstorm and storm) cannot be reproduced accurately, so that test data are difficult to use for algorithm iteration and comparison analysis. For example, the same radar observes the same weather at different times, echo characteristics may be significantly different due to temperature and humidity changes, and a stable reference test environment cannot be provided. The radar outfield test needs to coordinate airspace, deploy measurement and control equipment, consume live ammunition or meteorological balloons, and the single test cost can reach the level of megayuan. Meanwhile, due to geographical and climate restrictions, the test sites may be remote, increasing the investment in manpower, material resources and time. For example, testing for polar weather or typhoon scenarios is hardly achievable. Conventional methods have difficulty simulating extreme or complex weather conditions (e.g., strong turbulence, hail, polarized rainfall), and multi-objective interleaved scenarios (e.g., rain and snow mixed precipitation), limiting performance assessment of radar in complex environments. The measured data usually only cover common weather, and the robustness of the radar algorithm cannot be comprehensively verified. The outfield test is affected by real-time weather changes, parameters cannot be paused, played back or adjusted, and fault diagnosis and optimization and debugging are not facilitated. Engineers cannot "replay" specific meteorological events as needed to analyze radar responses, degrading commissioning accuracy. It is difficult to truly reflect the scattering characteristics of distributed weather targets, especially the lack of analog accuracy of dual polarization parameters (e.g., differential reflectivity, differential propagation phase shift, etc.). In the prior art, although some simulation methods (such as microwave darkroom radiation test or DRFM-based radio frequency injection) are still needed, part of external field support is still needed, and the hardware is complex and the cost is high, so that the problems cannot be thoroughly solved. Therefore, a digital analog technology that is free from weather dependence, programmable, and highly reproducible is needed to improve radar debugging efficiency and reliability. Disclosure of Invention The invention aims to provide a method for realizing dual-polarization phased array weather radar target simulation by using a digital receiver, which solves the problems of strong hardware dependence and high cost of the existing simulation technology, realizes high-fidelity and programmable simulation of weather target echoes, and supports efficient verification of a radar system. The method is characterized in that FPGA resources rich in digital intermediate frequency receivers in a phased array radar DBF receiving array are utilized, target echo signals received by each array element are simulated in the digital receivers in the form of digital intermediate frequency signals, phase information corresponding to the azimuth and pitch angle of a target relative to a receiving array surface is added to the echo signals, and a target simulation scheme of the digital intermediate frequency echo signals of each receiving branch is formed. The specif