Radar Level Measurement Research Articles

Dielectric Lens Antenna for Industrial Radar Applications

Industrial radar applications like tank level measurement is an important research and application area in radar technology. Radar level measurement is a safe solution even under extreme process conditions (pressure, temperature) and vapors. Special antennas are required to meet electromagnetic requirements such as high gain, low sidelobe level and high bandwidth. The small side-beam level and narrow main beam primarily minimize reflections from the side of the tank, while the bandwidth determines the distance resolution of the measurement system. Another requirement is a small size and good manufacturability of the antenna. The main promising solutions are the use of microstrip, horn or dielectric lens antennas for tank level measurement systems. After several tests, we have concluded that the optimal choice for tank level radar measurement task, in terms of integrability and antenna parameters, is a dielectric antenna. The dielectric antenna has many other applications in modern mobile systems as 5 and 6 G systems where these antennas are elements of antenna arrays of beamforming or MIMO systems. In this paper, a special dielectric lens antenna is presented, satisfying main requirements, namely a circular antenna cross section, high antenna aperture efficiency and low sidelobe level. The center frequency of the antenna is 26 GHz with a band width of 1 GHz. The paper presents the analytic investigation and design of the dielectric lens antenna and the circular wave guide transition in detail. The electromagnetic design of the antenna was carried out using CST Microwave Studio 3D software.

Dynamic and Full-Time Acquisition Technology and Method of Ice Data of Yellow River.

Regarding the ice periods of the Yellow River, it is difficult to obtain ice data information. To effectively grasp the ice evolution process in the ice periods of the typical reach of the Yellow River, a fixed-point air-coupled radar remote monitoring device is proposed in this paper. The device is mainly composed of an air-coupled radar ice thickness measurement sensor, radar water level measurement sensor, temperature measurement sensor, high-definition infrared night vision instrument, remote switch control, telemetry communication machine, solar and wind power supply, lightning protection, and slewing arm steel tower. The integrated monitoring device can monitor ice thickness, water level, air temperature, ice surface temperature, and other related parameters in real time. At present, devices have obtained the ice change process of fixed points in ice periods from 2020 to 2021. Through a comparison with manual data, the mean error of the monitoring results of the water level and ice thickness was approximately 1 cm. The device realizes the real-time monitoring of ice thickness and water level change in the whole cycle at the fixed position. Through video monitoring, it can take pictures and videos regularly and realize the connection between the visual river and monitoring data. The research results provide a new model and new technology for hydrological monitoring in the ice periods of the Yellow River, which has broad application prospects.

Correction technique for guided wave radar lpg level measurement sensors

Correction technique for guided wave radar lpg level measurement sensors

Non‐uniform sampling and super‐resolution method to increase the accuracy of tank gauging radar

Different methods are proposed for fluid level measurement in storage tanks. Majority of these methods have some in-contact elements or are based on mechanical waves which are vulnerable to changes due to temperature change, pressure change or ageing. Electromagnetic based (i.e. radar) level measurement is a contactless method and it is less vulnerable to such changes. However, a wide band or ultra-wide band radar signal should be transmitted in order to achieve the required accuracy. Usually, linear frequency modulation or step frequency waveforms are used for this goal and matched filter (MF) processing or fast Fourier transform (FFT) are used to find the true level of the liquid inside the tank. In this study, the authors have shown that, those super-resolution methods used for array signal processing and direction finding can be also used in tank gauging problem. Through the simulations and also practical laboratory test, it is shown that, if the frequency steps are selected non-uniformly, the super-resolution methods produce more accurate result compared with MF or FFT processing.

A Switch-Based Interpolated DFT for the Small Number of Acquired Sine Wave Cycles

The frequency of a real sinusoid is often estimated by interpolated discrete Fourier transform (IpDFT) algorithms because of the high accuracy and low computational burden. However, conventional IpDFTs focus on frequency estimation when the number of acquired sine wave cycles (NASC) is more than two. Frequency estimation with the small NASC is applicable in manufacturing processes, radar level measurement, and other applications. The spectral leakage of the negative frequency (the image component) significantly distorts the positive frequency when the NASC is small, dramatically degrading estimation accuracy. In particular, it is a challenging task for existing IpDFTs to provide high estimation accuracy when the NASC is less than one. In this paper, a switch-based IpDFT is proposed to provide high frequency estimation accuracy for $\text {NASC} . The theoretical variance of the algorithm in white Gaussian noise is formulated, which includes the upper bound and the lower bound. Computer simulations and real measurements are conducted to corroborate the theoretical analysis and to demonstrate that the proposed algorithm achieves better accuracy and antinoise capability for $\text {NASC} than existing algorithms.

English

In the radar level measurement instruments, the electromagnetic signal travel through air. Once it touches the material under test, it gets reflected back to the input end. The reflection of electromagnetic signal depends on electric and dielectric properties of material. Guided Wave Radar (GWR) meter isbased on the Time Domain Reflectrometry (TDR) principle for precise level measurement. TDR, which is well known measurement technique in telecommunication industries for evaluating electric and dielectric property of various material, used for precise level measurement and fault detection. Despite all advancement made within the last few years, there is still lack of low cost, small TDR meter equipment in market. This paper proposes a designon the development of a new miniaturized lowcost TDR meter capable of sampling a repetitive rectangular waveform, which is used as an excitation signal. The key techniques of pulse generation and time measurement are introduced with the selection of GWR probe for accuracy even when the measurement within a highly unstable environment. The signal generation with fast rising time is accomplished using small electronic circuit and the basic laboratory setup.Generally, there is a need of a high resolution, low power consuming, miniature TDR for dynamic level measurement in petrochemical, oil tank and shipbuilding industries application. Experimental results indicate the feasibility and improved functionality of the system.

Design of Radar Level Measurement Instrument Based on the UC3844

Introduced the internal function of UC3844, and analyzed the working important point of switching power supply. Planning and design of the radar level measurement instrument of multiple output power supply circuit.

Antenna Impact on the Gauging Accuracy of Industrial Radar Level Measurements

This paper deals with a systematic evaluation of the antenna impact on the gauging accuracy of industrial radar level measurements for process automation. By this means, a framework is provided by which the antenna parameters of major influence on the gauging accuracy can be identified. Guidelines are given to what extent an improvement of these parameters results in a measurable accuracy increase. Firstly, the radar system theory for monostatic level gauging and the emulation of such radar systems by software and hardware are briefly reviewed. Secondly, an analytical model of traveling-wave endfire antennas is introduced, allowing to separately study the influence of individual antenna parameters on the distance measurement accuracy. Thus, a direct relationship between characteristic antenna properties, such as the level of the pattern attenuation in the direction of a parasitic scatterer, and the gauging performance is obtained. The investigations are conducted for one specific pulse-based barycentric signal-processing scheme, which is predestined for industrial level gauging due to its low complexity and reliability. Finally, the results are verified by measurements within a compact radar test range.

Research on Improving LFMCW Radar Level Measurement Accuracy

LFMCW radar have a high range measuring accuracy in theory. But in practice, the picket fence effect of the FFT transform, making the range resolution and range accuracy in the same order of magnitude, can not meet the accuracy requirements for the near range measuring . Cascade FFT method is adopted to reduce frequency space of the main lobe of echo range spectrum on the FFT with increasing the less operation .The method can greatly improve the range precision of LFMCW Radar.

Research on Improving LFMCW Radar Level Measurement Accuracy

LFMCW radar have a high range measuring accuracy in theory. But in practice, the picket fence effect of the FFT transform, making the range resolution and range accuracy in the same order of magnitude, can not meet the accuracy requirements for the near range measuring . Cascade FFT method is adopted to reduce frequency space of the main lobe of echo range spectrum on the FFT with increasing the less operation .The method can greatly improve the range precision of LFMCW Radar.

Compact mode-matched excitation structures for radar distance measurements in overmoded circular waveguides

Abstract. This contribution deals with guided radar level measurements of liquid materials in large metal tubes, so-called stilling wells, bypass or still pipes. In the RF domain these tubes function as overmoded circular waveguides and mode-matched excitation structures like waveguide tapers are needed to avoid higher order waveguide modes. Especially for high-precision radar measurements the multimode propagation effects need to be minimized to achieve submillimeter accuracy. Therefore, a still pipe simulator is introduced with the purpose to fundamentally analyze the modal effects. Furthermore, a generalized design criterion is derived for the spurious mode suppression of compact circular waveguide transitions under the constraint of specified accuracy levels. According to the obtained results, a promising waveguide taper concept will finally be presented.

Tank seal for guided wave radar level measurement

Tank seal for guided wave radar level measurement

Mathematical Modeling of Iron and Steel Making Processes. Modeling the Liquid Levels in the Blast Furnace Hearth.

The drainage of a blast furnace hearth is analyzed on the basis of measurements of the instantaneous mass flow rates of tapped iron and slag, obtained from radar level measurements in the iron ladles and a pressure signal from the slag granulation drum. The measurements are used in a model estimating the levels of liquids in the blast furnace hearth, where correction terms have been introduced to prevent the level estimates from excessive drift. When applying the model on data from two Finnish blast furnaces, it was found that the estimated iron level exhibited strong correlation with the electromotive force (emf ) measured between two electrodes at the furnace shell. The results of the model are in general agreement with results reported by other investigators. The performance of the model is illustrated by some examples, and aprocedure for considering the case of a floating dead man is proposed.