Development and Current Situation of Radar Performance Parameter Measurement Simulation Training Platform

In Serbia (Yugoslavia), hail suppression programs have been operated continuously for the past twenty-two years. Important details of how silver iodide stimulates freezing remain largely unknown. Assuming that seeding increases the concentration of the ice particles by a given factor, changes in the radar parameters of clouds can be expected. Two-minute radar parameter changes are considered. The differences between no seed and seed cases are analysed. During the seeding periods of cloud life a more rapid change in clouds parameters is clearly noted.

In this paper, we present the evaluation of snow depth measurements that were conducted by an octo-copter mounted radar. The newly integrated radar and aerial platform was field trialed on sea ice near McMurdo Sound in Antarctica. In this trial, a 0.5 km length of snow-covered sea ice was selected for snow depth survey. Radar measurements were conducted as the octo-copter was flying at a height of 15 m and at a constant speed of 2 m/s over uniform sea ice. A separate validation measurement of snow depth along the same length of snow-covered sea ice provided ground truth data that were then used to compare with snow depth estimates from measured radar signals. Comparison between radar and ground truth measurements shows high correlation, at 0.90, between the two sets of snow depth data. Measurement error (difference between snow depth values measured by the radar and ground truth) has a mean of 0.1 cm and standard deviation of 3.1 cm.

Detection of steel bars embedded inside concrete for reinforcement has been one of the major goals of nondestructive testing methods for concrete. The use of radar in detecting steel bars is advantageous due to the sensitivity of electromagnetic waves to metallic objects and the versatility in using appropriate electromagnetic wave polarization waves to metallic objects and the versatility in using appropriate electromagnetic wave polarization with respect to the orientation of the bars. However, obtaining imagery of steel bars inside a lossy medium such as concrete requires sophisticated problem solving approaches including understanding of the electromagnetic properties of concrete, identification of proper radar measurement parameters as center frequency and bandwidth, and development of image reconstruction algorithms. This paper presents experimental results of radar measurements of laboratory size concrete specimens with or without steel bars. Sample radar imagery processed from raw measurement data is provided with discussion.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Fiber optic sensors based on Fiber Bragg Grating (FBG) technology have been successfully adopted for sensor measurements for almost two decades. The advantages offered by FBG sensors, such as Electro-Magnetic Interference immunity and inherent intrinsic safety, provide motivation for the development of a commercial measurement platform. With the development of an FBG Fabry-Perot cavity, a sensor with sub-picometer spectral width allows for a factor of 1000 times improvement in strain measurement. This thesis presents the development of a highly-accurate optical measurement platform based on the FBG Fabry-Perot cavity and Pound-Drever-Hall (PDH) laser locking technique that is demonstrated through the development of an optical torque sensor. With the fiber optic sensor designed as per the PDH requirements, the platform achieved a measurement accuracy of +/-0.015% of the full-scale torque value of 188N∙m. With the platform at ~$2,000, a successful demonstration of the platform and a fiber optic torque sensor is presented.

This paper presents a comprehensive measurement and calibration methodology for full-polarization characterization of radar targets at sub-terahertz (THz) frequencies. A novel three-object polarization calibration technique is proposed to address amplitude and phase imbalances in the measurement system. The method is implemented using a sub-THz radar cross-section measurement platform with twist waveguides for polarization switching. Experimental validation in an anechoic chamber demonstrates the method's effectiveness, achieving phase mismatch within 20°, polarization isolation better than 15 dB, and co-polarization amplitude imbalance below 2 dB. The calibrated data's accuracy is further confirmed through Cameron decomposition, showing excellent agreement with theoretical predictions. This work provides a robust framework for precise polarization characterization in the sub-THz regime, with potential applications in radar target recognition and imaging.

Ride comfort and handling qualities of a vehicle have attained much attention in the field of automobile. Vehicle manufacturers are trying to introduce as much ride comfort as possible without compromising handling qualities of vehicle. The two characteristics of the vehicle are linked with suspension system of vehicle. Good ride comfort means that the suspension system does not let road disturbance to reach the body of vehicle, while good handling qualities implies good road grip and maneuverability of the vehicle. Main objective to improve ride comfort is to elude physical fatigue and tiredness of driver while improvement in handling qualities will minimize chance of road accidents. Different suspension systems like passive, semi-active and active have been studied for long. Semi-active suspension system can provide change in damping coefficient to fulfill requirements of a good suspension system in a simple, easy and cost-effective way without requiring change in vehicle. Therefore, semi-active damper systems have gained more popularity in automobiles field. Designing control algorithm for semi-active suspension system is a complicated and challenging task. There have been many control algorithms to control damping coefficient, but no algorithm has utilized semi-active dampers to their full potential. This study investigates shortcomings of existing approaches, root cause of the problems and provides optimal solution to the problem. A suspension system involves different regions of operations that can be separated on the bases of operational constraints and stability of system. Existing methods do not use stability for designing their controllers or separating different regions. Furthermore, existing control strategies are based on linearized models and require gain adjustment and tuning to get better performance. Through analysis, it was found that there are three distinct regions. Damping force requirements for each region are different and critical. If wrong damping force is generated in any region, it may induce more acceleration/disturbance on vehicle, which is the main problem that existing methods suffer from. Proposed method generates right amount of force required at right time to suppress vibration by designing better control algorithm based on energy equations and dynamic equations. The proposed methods are validated by using simulations and experiments. For experimental validation of suspension system and attaining higher performance, accuracy of measurement system and parameters involved cannot be overlooked. Therefore, detailed investigations on accurate measurement system and parameter estimation methodology for suspension system were conducted. Thorough analysis on existing measurement system revealed critical errors in existing measurement system. To find out root cause of problems an analytical formula for evaluation of measurement system was derived. To overcome measurements issues it is required to use time, instead of encoders, as scalar base. This is not possible in existing methods, as sampling time of existing methods is dependent on other associated systems. Therefore, new measurement system is proposed, which uses high frequency clock and high sampling frequency to measure accurate time as soon as change in displacement occurs. This is same as using a stopwatch with a resolution as low as Nanoseconds. Simulations and experiments proved the proposed strategy and its effectiveness. The achieved accuracy from proposed method is comparable to the speed measurements system based on laser interferometer system. After having accurate measurement system for suspension system, accuracy of systems’ parameters is evaluated from accuracy point of view. The estimation problem is a mathematical problem in which number of independent equations are less than parameters to be estimated, which makes this problem unsolvable. Existing approaches use excitation method to generate additional equations and convert system to an overdetermined system and hence to be solved and an optimization problem. Getting overdetermined system is not a solution to the problem as independent equations are still the same. Furthermore, existing methods do not take care of coupling effects, eliminating or isolating noise and parameters from each other. Therefore, parameters estimation is not accurate. This motivated to develop an algorithm to estimate parameters with more accuracy and reliability. The proposed method converts estimation problem into a control problem and the parameters are updated by generating step-by-step update based on state feedback and projecting input on error of states or their functions. Properly designed desired trajectories for different parameters are used to decouple the parameter from other parameters. A systematic way of updating one parameter at a time in different cycles ensured convergence of parameters to true value even if absolute decoupling between parameters is not possible for complicate and nonlinear systems. The proposed method is validated, for linear and nonlinear problems by simulations and experiments.

To enhance the competence of the product in construction machinery, a proper testing system should be established for the construction machinery hydraulic system. Considering multi-site test and massive control of data processing in most construction machinery hydraulic measurement and control system, a testing platform applicable to different construction hydraulic systems is designed and presented in this paper. Composed of the upper and lower computers, the system is simple and convenient by means of Virtual Instrument Technology. Then it runs very well and proves reliable after debugging operation. Finally, the test-control platform can set manifold experiments in different working conditions.

In electronic warfare systems, wideband receivers are used to continuously monitor threat signals in the electromagnetic environment. In a modern threat environment, radar signals coexist with various communication signals within the same frequency band. These signals create interference in wideband receivers, hindering the accurate measurement of radar signal parameters. Interfering signals cause varying levels of distortion in digital and analog wideband receivers. In this study, the wideband FFT and instantaneous frequency measurement algorithms are utilized to analyze the impact of parameter estimation under different Signal-to-Interference Ratios (SIR), and their performance is analyzed with different FFT sizes under QPSK modulation.

In electronic confrontation, radar confrontation is an important part. Various radars widely used in modern warfare are the most important equipment in the field of information acquisition and precision guidance. Especially in the vast battle space, in order to achieve timely, accurate and comprehensive access to various target information, the role of radar is irreplaceable. Especially in the vast battle space, the role of radar is irreplaceable in order to achieve timely, accurate and comprehensive access to various target information. Therefore, in the war, it will not be able to protect their own survival and play combat effectiveness if not having the radar's ability to fight. At this time, that is the need for radar equipment in time to detect radar exposure, rapid measurement of radar signal parameters and identify threat signals, and targeted to do the implementation of interference or the implementation of technical attacks. In order to extract the parameters of the received signal to facilitate the subsequent research and analysis, this paper deduces the structure of the integrated filter bank in detail, and gives the reconfigurable filter bank structure design method, under the condition of accurate reconstruction of the signal. Based on the analysis of the design and calculation complexity of the filter bank structure, the dynamic reconfigurable design method con-sumes less hardware resources and wide application range, and the simulation structure also verifies the correctness and flexibility of the structure.

The errors in the current radial velocity measurements are examined using Bartlett beamforming and Multiple Signal Classification (MUSIC) direction-finding algorithms with a linear phased array antenna system. A variety of radar and environmental parameters are examined. Suggestions for the optimal choice of operating parameters are proposed. The MUSIC algorithm has shown promising performance in current measurement when beamforming is used to first establish the maximum current velocity. Comparisons of radar field data and current meter measurements show RMS radial velocity differences in magnitude of 7.44 and 6.64 cm s−1 for the Bartlett beamforming and MUSIC–Bartlett algorithms, respectively. The results indicate that there are advantages to using a MUSIC–Bartlett approach in operational applications.

Dual-polarization radar measurements and in situ measurements of supercooled liquid water and ice particles within orographic cloud systems are used to develop probabilistic criteria for identifying mixed-phase versus ice-phase regions of sub-0°C clouds. The motivation for this study is the development of quantitative criteria for identification of potential aircraft icing conditions in clouds using polarization radar. The measurements were obtained during the Mesoscale Alpine Programme (MAP) with the National Center for Atmospheric Research S-band dual-polarization Doppler radar (S-Pol) and Electra aircraft. The comparison of the radar and aircraft measurements required the development of an automated algorithm to match radar and aircraft observations in time and space. This algorithm is described, and evaluations are presented to verify its accuracy. Three polarization radar parameters, the radar reflectivity factor at horizontal polarization (ZH), the differential reflectivity (ZDR), and the specific differential phase (KDP), are first separately shown to be statistically distinguishable between conditions in mixed- and ice-phase clouds, even when an estimate of measurement uncertainty is included. Probability distributions for discrimination of mixed-phase versus ice-phase clouds are then developed using the matched radar and aircraft measurements. The probability distributions correspond well to a basic physical understanding of ice particle growth by riming and vapor deposition, both of which may occur in mixed-phase conditions. To the extent that the probability distributions derived for the MAP orographic clouds can be applied to other cloud systems, they provide a simple tool for warning aircraft of the likelihood that supercooled water may be encountered in regions of clouds.

This paper describes the development of an automatic measurement platform to study physical phenomena that depend on angular spatial position. The design concept focuses on a versatile and flexible system to be used in different science fields. The platform controls a goniometer angular motion, generates phenomena stimulus, and performs data logging and visualization. The measurement platform was developed with Matlab and Arduino integration. Platform performance was evaluated in two different fields, acoustics and lighting.

Open-field farming involves successive major processes such as preparation of soil, planting the seed, adding pesticides and fertilizers, irrigation, cultivation, and harvest. The main aim of all processes is to achieve maximum yield out of the available agricul-tural landscape. It is necessary to collect geo-referenced descriptive data on soil characteristics, such as soil penetration resistance and electrical conductivity before starting all these processes. In this context, agricultural robots offer highly promising technologies provid-ing valuable soil data, lower production costs, reduced manual labour, and maximum crop efficiency. The aim of this study is to design and develop a combined sensor platform and a GPS-guided 4WD agricultural autonomous robot to provide rapid measurement and mapping of the soil penetration resistance and the electrical conductivity for precision farming applications. The agricultural robot is a nonholonomic mobile robot, which has a differential steering mechanism and can be forwarded to stable-target points. The combined sensor platform, which is a y-axis shifter driven by a DC motor with reducer, consists of the Wenner array probes and load cell-based penetration rod. AutoCAD software was used for designing and drawing of the robot and measurement platform. All software was coded in Microsoft Visual Basic.NET programming language. Field studies were conducted to measure the soil penetration resistance, electrical conductivity, and determine the correlation between soil penetration resistance and electrical conductivity. As a result, the ranges of the soil measurement were observed between 1.13 MPa-2.14 MPa for penetration resistance and 0.14-0.33 dS/m for electrical conductivity. Results showed that there is a fairly strong negative relationship between the soil penetration resistance and the electrical conductivity (R2 = -0.78).

Sandia National Laboratories (SNL) is developing a low-cost, environmentally safe, and weather-proof sensor system that can be deployed offshore for extended periods of time for wind resource monitoring. The system has clear economic benefits over meteorological (met) tower approaches and is easily relocated to multiple locations across a project site. The end development goal is a buoy or barge-based, balloon-borne atmospheric measurement platform that operates autonomously in all but the most severe weather conditions, provides data of comparable accuracy to a met tower, and provides more accurate wind data at higher altitudes than floating lidar at half the cost.

In order to implement 3D measurement in different measurement systems with line structured-light sensor, the extrinsic matrix for transforming the position between the structured-light sensor and the measurement platform must be calibrated. An extrinsic calibration method, achieved by measuring the fixed point (the center of a standard ball) of the measuring system with the sensor on the different positions, was proposed. After collecting the images of the line structured-light stripe on the ball, the information of the slices can be extracted by direction template. The coordinate of the ball center in the laser plane frame can be calculated more accurately though image filtration and slice denoising. The extrinsic matrix can be solved by the conjugate pairs, which include the coordinates of both the ball center in the laser plane frame and the sensor in the measuring system. Experimental study was carried out on a four-axis CMM with a ball supplied by CIMCORE, of which the diameter was 25.40145 mm. 203 conjugate pairs were extracted and the extrinsic parameters were calculated. The ball was fitted with the calibrated parameters and the measured point cloud on the ball surface. The average error of the radius calculated was 0.0052mm. This method is simple; it can also be used in non-orthogonal measurement system.