scholarly journals Implementation of a Phase Synchronization Scheme Based on Pulsed Signal at Carrier Frequency for Bistatic SAR

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3188
Author(s):  
Yafeng Chen ◽  
Da Liang ◽  
Haixia Yue ◽  
Dacheng Liu ◽  
Xiayi Wu ◽  
...  
Keyword(s):  
Carrier Frequency ◽  
Phase Synchronization ◽  
Time Slot ◽  
Test Results ◽  
Factors Affecting ◽  
Bistatic Sar ◽  
Advanced Phase ◽  
Ground Validation ◽  
Bistatic Synthetic Aperture Radar ◽  
Synchronization Scheme

Phase synchronization is one of the key technical challenges and prerequisites for the bistatic synthetic aperture radar (SAR) system, which can form a single-pass interferometry system to perform topographic mapping. In this paper, an advanced phase synchronization scheme based on a pulsed signal at carrier frequency is proposed for a bistatic SAR system and it is verified by a ground validation system. In the proposed phase synchronization scheme, the pulsed signal at carrier frequency is used for phase synchronization link, and it is exchanged by virtue of a time slot between radar signals. The feasibility of the scheme is proven by theoretical analysis of various factors affecting the performance of phase synchronization, and the reliability of the scheme is verified by the test results of the ground validation system.

An Advanced Phase Synchronization Scheme for LT-1

2020 ◽  
Vol 58 (3) ◽  
pp. 1735-1746 ◽  
Author(s):  
Guodong Jin ◽  
Kaiyu Liu ◽  
Dacheng Liu ◽  
Da Liang ◽  
Heng Zhang ◽  
...  
Keyword(s):  
Phase Synchronization ◽  
Advanced Phase ◽  
Synchronization Scheme

scholarly journals An Advanced Phase Synchronization Scheme Based on Coherent Integration and Waveform Diversity for Bistatic SAR

2021 ◽  
Vol 13 (5) ◽  
pp. 981
Author(s):  
Da Liang ◽  
Heng Zhang ◽  
Yonghua Cai ◽  
Kaiyu Liu ◽  
Ke Zhang
Keyword(s):  
Hearing Aids ◽  
Phase Synchronization ◽  
Phase Error ◽  
Radar Signal ◽  
Cocktail Party Problem ◽  
Waveform Diversity ◽  
Coherent Integration ◽  
Advanced Phase ◽  
Synchronization Signal ◽  
Synchronization Scheme

In the bistatic synthetic aperture radar (BiSAR) system, the deviation between two oscillators in different platforms will cause an additional modulation of BiSAR echoes. Therefore, phase synchronization is one of the key issues that must be addressed for the BiSAR system. The oscillator phase error model and the principle of phase synchronization are firstly described. The waveform diversity technology has been widely used in many fields, for example, the hearing aids device and the recognition of auditory input source in cocktail party problem. Inspired by this, an advanced phase synchronization scheme based on coherent integration and waveform diversity is proposed. The synchronization signal and radar signal are orthogonal signals which can be separated by using waveform diversity technique. After extracting the synchronization signal, the phase synchronization accuracy can be further improved by coherent integration. The transmission of synchronization signals between two synchronization antennas is analyzed, followed by the theoretical error analysis. Then, the processing of separating the echo signal and synchronization signal is described in detail. The simulation experiments are performed. The accuracy of phase synchronization can reach 1 degree, which verifies the effectiveness of the proposed synchronization scheme.

Improving the Strength of Abrasive Wheels and Optimizing the Control over the Strength of Composite Abrasive Materials

2019 ◽  
Vol 946 ◽  
pp. 380-385
Author(s):  
Boris A. Chaplygin ◽  
Viacheslav V. Shirokov ◽  
Tat'yana A. Lisovskaya ◽  
Roman A. Lisovskiy
Keyword(s):  
Mechanical Properties ◽  
Test Results ◽  
Key Factors ◽  
Special Equipment ◽  
Material Density ◽  
Factors Affecting ◽  
Control Factors ◽  
Reinforcing Material ◽  
Special Studies ◽  
First Time

The strength of abrasive wheels is one of the key factors affecting the performance of abrasive machining. The paper discusses ways to improve the strength of abrasive wheels. The stress-state mathematical model presented herein is a generalization of the existing models. It is used herein to find for the first time that there are numerous optimal combinations of the elastic modulus and reinforcing material density, which result in the same minimum value of the objective function. It is found out that increasing the radius of the reinforcing component while also optimizing the mechanical properties of its material may increase the permissible breaking speed of the wheel several times. We herein present a regression equation and a nomogram for finding the optimal combination of control factors. Conventional methods for testing the mechanical properties of materials, which have been proven reliable for testing metals and alloys, are not as reliable for testing abrasive materials, as the test results they generate are not sufficiently stable or accurate. We therefore propose an alternative method that does not require any special equipment or special studies.

scholarly journals Evaluation of Bleeding Resistance in Chip Seal and Asphalt Emulsion Residue Rheology

Coatings ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 670
Author(s):  
Preeda Chaturabong
Keyword(s):  
Influence Factors ◽  
Application Rate ◽  
Test Methods ◽  
Test Results ◽  
Asphalt Emulsion ◽  
Aggregate Gradation ◽  
Factors Affecting ◽  
Promising Tool ◽  
Chip Seal ◽  
Asphalt Emulsions

Chip seal bleeding is influenced by many factors, including design inputs, material properties, and project-specific conditions. It reduces the surface texture of the pavement and thus compromises the safety of the traveling public. Even though factors that bring about premature bleeding are known, currently, no laboratory test methods for evaluating bleeding in chip seals have been specified. The objective of this paper is to present the results of an investigation of the influence factors of asphalt emulsion residue properties measured by the ASTM D7405 multiple stress creep and recovery (MSCR) test, as well as other factors related to chip seal bleeding resistance as measured by the modified loaded wheel test (MLWT). In this study, the MSCR test was used as a tool for evaluating the performance of asphalt emulsions because it has been identified as a potential test related to bleeding in the field. In addition, MLWT was selected as a tool for evaluating chip seal bleeding performance in the laboratory. The results of the MLWT showed that the emulsion application rate (EAR), aggregate gradation, and emulsion properties were significant factors affecting bleeding. The MSCR test was found to be a promising tool for the performance evaluation of asphalt emulsion residue, as the test was able to differentiate between emulsion chemistries and modifications in terms of sensitivity to both temperature and stress. In relation to chip seal bleeding resistance, only the creep compliance (Jnr) obtained from the MSCR test results was identified as a significant property affecting potential for bleeding.

Field Tests of Guide Vanes and Runner Blades of a Large Bulb Turbine for Output Deficiency Diagnosis

2012 ◽  
Vol 212-213 ◽  
pp. 1057-1061 ◽  
Author(s):  
Zhong Liu ◽  
Zhu Qing Huang ◽  
Shu Yun Zou ◽  
Hong De Rao
Keyword(s):  
Field Tests ◽  
Economic Loss ◽  
Hydropower Plant ◽  
Test Results ◽  
Guide Vanes ◽  
Factors Affecting ◽  
Runner Blade ◽  
Main Factors ◽  
Theoretical Analyses ◽  
Bulb Turbine

The 3# bulb turbine in Hongjiang Hydropower Plant has faced the problem of output deficiency since its commission in Sept. 2003, which caused a large economic loss. Following simple theoretical analyses on the main factors affecting the turbine’s output and efficiency, the field test schemes were determined to measure the shapes and intervals of guide vanes and runner blades of the 3#, 5# and 6# turbines. The test results discover that the average blade intervals of the 3# turbine are generally less than those of the 5# one. Suggestions on runner blade installation adjustment and combined curve modification are given.

scholarly journals The small strain stiffness from bender elements tests for clayey soils

2018 ◽  
Vol 50 (4) ◽  
pp. 353-371
Author(s):  
Katarzyna Markowska-Lech ◽  
Wojciech Sas ◽  
Mariusz Lech ◽  
Katarzyna Gabryś ◽  
Alojzy Szymański
Keyword(s):  
Field Tests ◽  
Small Strain ◽  
Test Results ◽  
Bender Elements ◽  
Element Analysis ◽  
Factors Affecting ◽  
Small Strain Stiffness ◽  
Seismic Wave Velocities ◽  
Case Basis ◽  
Hardening Soil Model

Abstract The shear modulus of soils at small strain (G0) is one of the input parameters in a finite element analysis with the hardening soil model with small strain stiffness, required in the advanced numerical analyses of geotechnical engineering problems. The small strain stiffness can be determined based on the seismic wave velocities measured in the laboratory and field tests, but the interpretation of test results is still under discussion because of many different factors affecting the measurements of the wave travel time. The recommendations and proposed solutions found in the literature are helpful as a guide, but ought to be adopted with a certain measure of care and caution on a case-by-case basis. The equipment, procedures, tests results and interpretation analyses of bender elements (BE) tests performed on natural overconsolidated cohesive soils are presented.

scholarly journals ANALISYS OF THE INFLUENCE OF GLUE JOINTS ON THE MEASUREMENT OF PHYSICAL PROPERTIES OF STRUCTURAL ELEMENTS USING FIBER BRAGG GRATING

2020 ◽  
Vol 10 (3) ◽  
pp. 99-102
Author(s):  
Tomasz Zieliński ◽  
Łukasz Zychowicz
Keyword(s):  
Stainless Steel ◽  
Physical Properties ◽  
Fiber Bragg Grating ◽  
Transmission Spectrum ◽  
Measuring Transducer ◽  
Bragg Grating ◽  
Transmission Characteristic ◽  
Test Results ◽  
Structural Elements ◽  
Factors Affecting

The research presents the analysis of the influence of the glue connection on the measurement of elongation of stainless steel and aluminum samples by means of fiber Bragg grating (FBG) with uniform fibers used as a measuring transducer. Research indicates two possible factors affecting the deformation of the transmission spectrum obtained during elongation measurement. One of them is the type of adhesive that is used to make the connection between the fiber Bragg grating and the tested sample. The second possible factor is method of connection's execution. The need for research on glue connection resulted from the formation of defects mainly in the form of numerous side bands visible in the transmission spectrum during the measurement of elongations. The test results were presented in the form of graphs obtained on the basis of transmission characteristic.

scholarly journals EQUIPMENT PRICE FORECAST BASED ON T-S FUZZY NEURAL NETWORK

2018 ◽  
Vol 48 (4) ◽  
pp. 305-309
Author(s):  
G. P. JIANG ◽  
L. XIE ◽  
S. X. SUN
Keyword(s):  
Neural Network ◽  
Wavelet Neural Network ◽  
Test Results ◽  
Factors Affecting ◽  
Price Forecast ◽  
Network Algorithm ◽  
Auction Price ◽  
Variable Weight ◽  
Fuzzy Neural ◽  
Neural Network Algorithm

As we all know, the factors affecting the price of equipment are more complicated, but these factors still have a great correlation. How can we accurately predict the price of equipment? Based on the study of the tight support and smoothness of wavelet function, this paper proposes a correlation variable weight wavelet neural network algorithm to predict the price of 162 devices. The test results show that if the weight is not reduced, the predicted price is 0, and the error is still large. However, by arranging the data from small to large, the variable weighted wavelet neural network algorithm is used to predict the result closer to the auction price, which overcomes the incompatibility of the algorithm iteration and provides a reference for accurately predicting the price of the device.

Phase Synchronization and Doppler Centroid Estimation in Fixed Receiver Bistatic SAR Systems

2008 ◽  
Vol 46 (11) ◽  
pp. 3459-3471 ◽  
Author(s):  
Paco Lopez-Dekker ◽  
Jordi J. Mallorqui ◽  
Pau Serra-Morales ◽  
JesÚs Sanz-Marcos
Keyword(s):  
Phase Synchronization ◽  
Bistatic Sar ◽  
Centroid Estimation
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