Radar Echo Simulation Research Articles

A fast synthetic aperture radar echo simulation technique based on ray tracing

A fast synthetic aperture radar echo simulation technique based on ray tracing

A Radar Echo Simulator for the Synthesis of Randomized Training Data Sets in the Context of AI-Based Applications

A Radar Echo Simulator for the Synthesis of Randomized Training Data Sets in the Context of AI-Based Applications

Simulation and sensitivity analysis for cloud and precipitation measurements via spaceborne millimeter-wave radar

Abstract. This study presents a simulation framework for cloud and precipitation measurements via spaceborne millimeter-wave radar composed of eight submodules. To demonstrate the influence of the assumed physical parameters and to improve the microphysical modeling of the hydrometeors, we first conducted a sensitivity analysis. The results indicated that the radar reflectivity was highly sensitive to the particle size distribution (PSD) parameter of the median volume diameter and particle density parameter, which can cause reflectivity variations of several to more than 10 dB. The variation in the prefactor of the mass–power relations that related to the riming degree may result in an uncertainty of approximately 30 %–45 %. The particle shape and orientation also had a significant impact on the radar reflectivity. The spherical assumption may result in an average overestimation of the reflectivity by approximately 4 %–14 %, dependent on the particle type, shape, and orientation. Typical weather cases were simulated using improved physical modeling, accounting for the particle shapes, typical PSD parameters corresponding to the cloud precipitation types, mass–power relations for snow and graupel, and melting modeling. We present and validate the simulation results for a cold-front stratiform cloud and a deep convective process with observations from a W-band cloud profiling radar (CPR) on the CloudSat satellite. The simulated bright band features, echo structure, and intensity showed a good agreement with the CloudSat observations; the average relative error of radar reflectivity in the vertical profile was within 20 %. Our results quantify the uncertainty in the millimeter-wave radar echo simulation that may be caused by the physical model parameters and provide a scientific basis for optimal forward modeling. They also provide suggestions for prior physical parameter constraints for the retrieval of the microphysical properties of clouds and precipitation.

Scheme design of the optimal background clutter suppression for impulse radio ultrawide band radar in complex fire environment: a simulation and experimental study

Impulse radio ultrawide band (IR-UWB) radar possesses several advantages, such as heat flow insensitivity, high resolution, great penetration, good mobility, and lightweight, making it a promising technology for detecting and rescuing individuals trapped in fire scenarios. However, reliable detection and extraction of vital signs of trapped people in the presence of complex fire environment, such as water droplets, smoke, wall occlusions, and reflections, require an optimal background clutter suppression scheme designed specifically for fire scenarios. This study comprehensively evaluates 20 background noise suppression schemes using an exhaustive approach that involves constructing radar echo simulation signals and designing an evaluation method for algorithms. The practical applicability of the improved design solutions was evaluated by conducting small-scale fire experiments in an acrylic chamber. The results indicate that the designed scheme is effective in overcoming the background interference from the combustion environment and is capable of supporting subsequent trajectory identification and vital sign extraction in the fire scene environment.

Radar echo simulation of dynamically rotating wind turbine blades based on 3D scattering center

Introduction: High-fidelity simulation of the radar echo from the wind turbine (WT) for accurate acquisition of Doppler features, is the key issue in addressing radiation interference from the wind farm on the nearby radar station. In view of the limitation of the conventional scattering center-based equivalent model to reflect the complex surface of blades, it is difficult to simulate the rotating blades’echo accurately with the existing algorithm. Therefore, we proposed a simulation method based on a 3D scattering center extraction to deal with it.Methods: Therefore, we proposed a simulation method based on a 3D scattering center extraction to deal with it. First, the method of scattering center equivalence to blade scattering is used in order to reduce the modelling as well as the solution of electromagnetic scattering from the multi-space attitude of the blade, which is different from the existing algorithm. Since the geometry affects the parameters of the scattering center, an orthogonal matching pursuit greedy algorithm is used to extract the parameter of the 3D scattering center model.Results: Therefore, the temporal correspondence between the scattering center and the blade motion characteristics is established, resulting in a reconstruction of the scattered field data of the rotating blades. Consequently, the real-time simulation and Doppler characteristic of blades echoes are achieved using the Short Time Fourier Transform (STFT).Discussion: A comparison of the results with the data obtained from the GTD scattering center model verififies the accuracy of the proposed method.

A New Radar Echo Generation Model for Ultra-Low Altitude Targets in Far-Field Conditions

This paper proposed a new radar echo simulation method for ultra-low altitude targets in far-field conditions. Based on the electromagnetic (EM) scattering calculation of target and environment, combined with the weighted four-path model, the scattering data of target, environment, and multipath are obtained. The Range-Doppler ring partitioning method is used to determine the size of the minimum resolution units, and then the environment is divided into several scattering elements. By using the method of temporal decomposition, the wide-time pulse is decomposed into a plurality of narrow pulse signals, and the narrow pulses act on scattering elements with different distances and orientations in space. The total echo is obtained by a linear superposition of the responses of each scattering unit. In addition, the numerical results with different parameters, including signal bandwidths, target types, and target height, are simulated and analysed. The simulation results demonstrate that the proposed method can provide a better description of the scattering characteristics of sea-skimming targets in complex scenes in far-field conditions. Meanwhile, it can be applied to the detection and recognition of ultra-low altitude targets above the sea surface.

Millimeter-Wave Radar in-the-Loop Testing for Intelligent Vehicles

Intelligent vehicle testing and validation technology is a hotspot in the field of intelligent vehicles. Millimeter-wave radar has been widely used in intelligent vehicles and advanced driving assistant systems (ADASs). Owing to low efficiency, high maintenance cost and limited scenario types, the traditional real-vehicle-testing can make it difficult to meet the requirements of intelligent vehicle testing. Also, the degree of reality of millimeter-wave radar sensor models in the virtual test platform is not convincing enough. To solve the mentioned problems, the millimeter-wave radar in-the-loop (mmRil) testing for intelligent vehicles is proposed in this study. First, the radar echo simulation method is developed. Next, based on the millimeter-wave flight time, Doppler frequency shift and the radar power attenuation equation, the mmRil test system is built. A geometric model of a radar target detection and a power attenuation model under bad weather conditions are established. Then, the accuracy of the testbench is verified. Finally, a typical intelligent vehicle control strategy is used for testing under various working conditions and bad weather using the mmRil testbench. The test results show that the mmRil testing has higher authenticity and accuracy than the simulation testing and can be used to test the intelligent vehicle algorithms under severe weather conditions. Compared with the real vehicle testing, the mmRil testing has higher efficiency, repeatability and safety. Therefore, the mmRil testing represents an indispensable testing method in the field of intelligent vehicle testing.

Radar echo simulation of wind turbines array based on scattering center

PurposeThis paper aims to propose a method for accurate radar echo simulation of wind turbines (WTs) array. It can solve the problem of passive interference from wind farms to neighboring radar stations.Design/methodology/approachFirst of all, the equivalent model of scattering centers of a single WT is obtained by using the spatial spectrum estimation method, and the accuracy of this model is verified by the scaled model experiment; then scattering centers model of WTs array was established by using the spatial coordinate transformation method. According to the position relationship between the model and the radar, and combined with the multipath scattering theory, the radar echo equation of WTs array was deduced. Finally, the simulation analysis is carried out with the four GoldWind 77/1500 WTs as an example and compared with the traditional methods.FindingsThis paper verifies the accuracy of the equivalent model of scattering centers through the WT scaled model experiment, and through simulation analysis, it is found that the result of this method is more consistent with the multipath scattering of radar echo between WTs array in practical engineering than the traditional method.Originality/valueBased on the theory of high-frequency scattering, this paper introduces scattering centers into the solution of radar echo and considers the multipath scattering of radar echo, then a method for solving the radar echo of WTs array based on scattering centers is proposed.

A Novel Method for Radar Echo Simulation based on Fast-Constructed Database

This paper presents a novel method for fast calculation of radar echo in near-field regions after the equivalent source has been computed by method of moments (MoM). An easy-to-access near-field database (NFDB) is established, which is built on the auxiliary tetrahedral meshes surrounding the near-field regions of interest. The near-fields calculation (NFC) of arbitrary observation points can be expressed explicitly via the NF-DB. An efficient matrix compression scheme named random sampling-based butterfly factorization (RS-BF) is proposed to speed up the construction of NFDB. With this approach, each group of O(N) elements in the database can be calculated through one fast matrix-vector multiplication operation that has a computational complexity below O(Nlog N). The proposed method can avoid time-consuming point-by-point NFC of the traditional methods. Several numerical examples are presented to demonstrate the accuracy and efficiency of this method. In particular, the echo simulation of a missile-target encounter example is presented to illustrate its capability for practical applications.

Simulation and analysis of wind turbine radar echo based on 3-D scattering point model

Simulation and analysis of wind turbine radar echo based on 3-D scattering point model

Target dynamic radar echo simulation based on sensor

Abstract Aiming at the influence of radar sensor on radar echo during measurement, a sensor-based target dynamic radar echo simulation method is proposed. According to the working principle of the sensor and the radar equation, the sensor model of radar echo is established. A frequency domain modeling process combining sensor is proposed, and the influence of the sensor on the radar echo simulation result is analyzed.

Implementation of SAR Echo Simulation Algorithm on Heterogeneous Embedded Computing Platform

The Synthetic Aperture Radar (SAR) echo simulation is to obtain the SAR original echo signal by performing reverse operation on the pre-set SAR image. The traditional platforms used to implement the simulation algorithms like central processing unit (CPU) + graphic processing unit (GPU) and digital signal processor (DSP) + field programmable gate array (FPGA) have disadvantages such as high power consumption or complicated programming. In order to make up for these shortcomings, the implementation structure of the SAR echo simulation algorithm was improved to be applicable on the heterogeneous embedded platform with the basic SAR simulation algorithms digitized and decomposed. Base on the improved structure, a mobile GPU based heterogeneous computing platform with one multiprocessor system-on-chip (MPSoC) and multiple GPUs was designed to implement SAR echo simulation algorithm. The platform can simultaneously utilize the real-time nature of register transfer level (RTL) design and the ease of programming on GPU. It can achieve relatively faster computing power at lower power consumption and has the characteristics of miniaturization and mobility.

Space‐variant analysis and target echo simulation of geosynchronous SAR

The geosynchronous synthetic aperture radar (GEO SAR) echo simulation has an important significance for GEO SAR system design and image algorithm verification. The study discusses the main steps of the GEO SAR echo simulation process and the calculation of key parameters. At the same time, because GEO SAR has a high orbital altitude and a long-time delay, the error caused by the ‘go-stop-go’ hypothesis must be taken into account. For this reason, the authors have studied the slant range iterative model without the assumption. It is used to calculate the distance between the satellite and target in the echo simulation. Experimental results show that the method is effective and feasible. Based on this, the space variant characteristics of GEO SAR are analysed in detail. It can be seen that the echo signals do not satisfy the range and azimuth invariance.

Parameter Inversions of Multi-Layer Media of Mars Polar Region with Validation of SHARAD Data

HF (high frequency) radar sounder technology has been developed for several missions of Mars surface/subsurface exploration. This paper presents a model of rough surface and stratified sub-surfaces to describe the multi-layer structure of Mars polar deposits. Based on numerical simulation of radar echoes from rough surface/stratified interfaces, an inversion approach is developed to obtain the parameters of Polar Layered Deposits, i.e. layers thickness and dielectric constants. As a validation example, the SHARAD radar sounder data of the Promethei Lingula of Mars South Polar region is adopted for parameters inversion. The result of stratification is also analyzed and compared with the optical photo of the deep cliff of Chasma Australe canyon. Dielectric inversions show that the deposit media are not uniform, and the dielectric constants of the Promethei Lingula surfaces are large, and become reduced around the depth of 20 m - 30 m, below where most of the deposits are nearly pure ice, except a few thin layers with a lot of dust.

用于雷达回波仿真的小型化微波光纤延迟线

用于雷达回波仿真的小型化微波光纤延迟线

The design and implementation of a multi-waveform radar echo simulator.

Radar simulator is an effective tool for performance assessment of radar systems by accurately reproducing echo signals from complicated environment. This paper presents a design of fast multi-waveform radar echo generation based on deconvolution method. First, scene information is retrieved from outfield data based on improved conjugate gradient algorithm. Then, the new radar echoes are generated through convolution of new transmitted signal and restored scene information. A fast and area-efficient field programmable gate array realization is provided to meet the real-time requirement of radar echo simulation. Finally, a series of experiments are performed to evaluate the effectiveness of proposed radar simulation instrument.

Simulation of Multiangular Radar Echoes for Speed Measurement During CE-3 Landing on the Lunar Sinus Iridum Surface

The main objective of the Chinese Chang'E-3 (CE-3) lunar satellite is to achieve soft-landing and roving exploration on the lunar surface. A multibeam radar in the lunar lander is implemented to measure the echoes from the lunar rough surface during its descending and to derive the speed of the lander. In this paper, numerical simulation of multiangular radar echoes and speed inversions from Doppler frequency are presented. An area of the Lunar Sinus Iridum bay, as landing site, is specifically selected. The rough surface described with the real DTM data is first divided into triangular patches for numerical Kirchhoff approximation calculation. The radar echoes of multiangular radar beams of CE-3 during the landing are numerically simulated. The echo phase and the Doppler frequency are then derived to obtain the vertical speed.

Hardware-in-the-loop simulation technology of wide-band radar targets based on scattering center model

Hardware-in-the-loop (HWIL) simulation technology can verify and evaluate the radar by simulating the radio frequency environment in an anechoic chamber. The HWIL simulation technology of wide-band radar targets can accurately generate wide-band radar target echo which stands for the radar target scattering characteristics and pulse modulation of radar transmitting signal. This paper analyzes the wide-band radar target scattering properties first. Since the responses of target are composed of many separate scattering centers, the target scattering characteristic is restructured by scattering centers model. Based on the scattering centers model of wide-band radar target, the wide-band radar target echo modeling and the simulation method are discussed. The wide-band radar target echo is reconstructed in real-time by convoluting the transmitting signal to the target scattering parameters. Using the digital radio frequency memory (DRFM) system, the HWIL simulation of wide-band radar target echo with high accuracy can be actualized. A typical wide-band radar target simulation is taken to demonstrate the preferable simulation effect of the reconstruction method of wide-band radar target echo. Finally, the radar target time-domain echo and high-resolution range profile (HRRP) are given. The results show that the HWIL simulation gives a high-resolution range distribution of wide-band radar target scattering centers.

A Novel Technique for Radar Depth Sounding of Fast Outlet Glaciers and Ice-Sheet Margins

The surface clutter simulator and the digital filter technique are developed for sounding and imaging of a subsurface stratified structure with arbitrary ice surface roughness of fast outlet glaciers and ice-sheet margins, which provides a new insight into the strong surface clutter reduction. The radar signal simulation method developed by employing Kirchhoff approximation of rough surface scattering and the ray tracing of geometric optics theory can give clear understanding of electromagnetic (EM) wave radiation and propagation through multilayer stratified media and support the interpretation of radar actual observations for retrieving good information on ice bed and internal layers. The radar sounder echo simulator can calculate the EM scattering from ice internal multilayer rough interfaces and identify whether deeper layers or ice-bed nadir echoes masked by a strong surface off-nadir echo still return to the radar receiver or not, which offers an important tool for designing and optimizing radar system performance. The numerical spline interpolation technique is proposed to discretize the 3-D real ice topography into a suitable triangulated mesh for obtaining higher accurate radar simulation data compared with the facet method. The digital filter technique can be complementary to conventional processing methods in order to distinguish an ice bed from a strong surface clutter with an extremely crevassed rough surface in Antarctica and Greenland. Ice data processing results of certain outlet glaciers' topography are demonstrated. The presented unified data analysis methodology can be also applied to planetary exploration.

Study on Echo Fidelity of Radar Simulator

Echo fidelity is an important characteristic of radar simulator and it influences accuracy and reliability of radar test directly. This paper introduces the research status of simulator fidelity and sort out the definition and property of radar echo simulation fidelity. Then we propose the numerical calculation methods for individual indicators, including similarity calculation, dissimilarity computing and interval changes three parts. Finally, on the basis of the evaluation system, we propose two calculation methods for entirety fidelity, they are weighted numerical calculation and umbrella figure methods.