Novel 2D velocity estimation method for large transient events in plasmas

2021 ◽  
Vol 92 (8) ◽  
pp. 083508
Author(s):  
M. Lampert ◽  
A. Diallo ◽  
S. J. Zweben
Keyword(s):  
Estimation Method ◽  
Velocity Estimation ◽  
Transient Events

scholarly journals Bio-Inspired Covert Active Sonar Strategy

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2436 ◽  
Author(s):  
Jiajia Jiang ◽  
Xianquan Wang ◽  
Fajie Duan ◽  
Chunyue Li ◽  
Xiao Fu ◽  
...  
Keyword(s):  
Marine Mammals ◽  
Estimation Method ◽  
Sperm Whale ◽  
Waveform Design ◽  
Velocity Estimation ◽  
Estimation Methods ◽  
Range Resolution ◽  
Active Sonar ◽  
Ocean Noise ◽  
Underwater Target

The covertness of the active sonar is a very important issue and the sonar signal waveform design problem was studied to improve covertness of the system. Many marine mammals produce call pulses for communication and echolocation, and existing interception systems normally classify these biological signals as ocean noise and filter them out. Based on this, a bio-inspired covert active sonar strategy was proposed. The true, rather than man-made sperm whale, call pulses were used to serve as sonar waveforms so as to ensure the camouflage ability of sonar waveforms. A range and velocity measurement combination (RVMC) was designed by using two true sperm whale call pulses which had excellent range resolution (RR) and large Doppler tolerance (DT). The range and velocity estimation methods were developed based on the RVMC. In the sonar receiver, the correlation technology was used to confirm the start and end time of sonar signals and their echoes, and then based on the developed range and velocity estimation method, the range and velocity of the underwater target were obtained. Then, the RVMC was embedded into the true sperm whale call-train to improve the camouflage ability of the sonar signal-train. Finally, experiment results were provided to verify the performance of the proposed method.

A new velocity estimation method using spectral identification of noise

2008 ◽  
Vol 19 (3-4) ◽  
pp. 197-203 ◽  
Author(s):  
Stéphane Fischer ◽  
Philippe Schmitt ◽  
Denis Ensminger ◽  
Farès Abda ◽  
Anne Pallares
Keyword(s):  
Estimation Method ◽  
Velocity Estimation ◽  
Spectral Identification

Auto-landing guidance for unmanned aerial vehicle with engine flame-out

2019 ◽  
Vol 233 (13) ◽  
pp. 4864-4878 ◽  
Author(s):  
Young-Sam Kim ◽  
Min-Jea Tahk
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Trajectory Generation ◽  
Vertical Plane ◽  
Estimation Method ◽  
Terminal Velocity ◽  
Velocity Estimation ◽  
Total Loss ◽  
Aerial Vehicle ◽  
Loss Of Thrust

Landing is the most dangerous phase of the entire flight phases. If the total loss of thrust occurs during flight, a powered aircraft converts to a glider, which can use kinetic and potential energy only. For this reason, a proper scheme is needed for safe landing in cases of the total loss of thrust. This paper presents three-dimensional unpowered auto-landing guidance based on trajectory generation, expanding the concept of the energy-to-range ratio. We develop the terminal velocity estimation method for a horizontal plane applied to three-dimensional space; this method is based on the previously suggested terminal velocity estimation method for a vertical plane. Then, we show trajectory generation for landing guidance combining vertical with horizontal waypoints. The proposed auto-landing guidance with trajectory generation is evaluated by numerical simulation.

scholarly journals Vehicle Velocity Estimation Fusion with Kinematic Integral and Empirical Correction on Multi-Timescales

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1242
Author(s):  
Jiangyi Lv ◽  
Hongwen He ◽  
Wei Liu ◽  
Yong Chen ◽  
Fengchun Sun
Keyword(s):  
Autonomous Vehicles ◽  
Estimation Error ◽  
Longitudinal Velocity ◽  
Estimation Method ◽  
Velocity Estimation ◽  
Model Parameters ◽  
Lateral Velocity ◽  
Empirical Correction ◽  
Vehicle Velocity ◽  
Wide Range

Accurate and reliable vehicle velocity estimation is greatly motivated by the increasing demands of high-precision motion control for autonomous vehicles and the decreasing cost of the required multi-axis IMU sensors. A practical estimation method for the longitudinal and lateral velocities of electric vehicles is proposed. Two reliable driving empirical judgements about the velocities are extracted from the signals of the ordinary onboard vehicle sensors, which correct the integral errors of the corresponding kinematic equations on a long timescale. Meanwhile, the additive biases of the measured accelerations are estimated recursively by comparing the integral of the measured accelerations with the difference of the estimated velocities between the adjacent strong empirical correction instants, which further compensates the kinematic integral error on short timescale. The algorithm is verified by both the CarSim-Simulink co-simulation and the controller-in-the-loop test under the CarMaker-RoadBox environment. The results show that the velocities can be accurately and reliably estimated under a wide range of driving conditions without prior knowledge of the tire-model and other unavailable signals or frequently changeable model parameters. The relative estimation error of the longitudinal velocity and the absolute estimation error of the lateral velocity are kept within 2% and 0.5 km/h, respectively.

scholarly journals An Improved Velocity Estimation Method for Wideband Multi-Highlight Target Echoes in Active Sonar Systems

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2794 ◽  
Author(s):  
Shuxia Huang ◽  
Shiliang Fang ◽  
Ning Han
Keyword(s):  
Matched Filter ◽  
Estimation Method ◽  
Velocity Estimation ◽  
Filter Method ◽  
Improved Method ◽  
Matching Algorithm ◽  
Active Sonar ◽  
Estimation Performance ◽  
Effective Performance ◽  
Sonar Systems

In active sonar systems, the target echoes are usually equivalent to a superposition of the Doppler-scaled reflections from multiple highlights. The reflections overlap with each other both in the time and frequency domain, which results in a decreased velocity estimation performance. Recently, the hyperbolic-frequency modulated signal has been widely employed in sonar systems for moving targets due to its Doppler tolerance, while the precise velocity estimation becomes a great challenge under such conditions. In this paper, the echo c is modeled onsidering a target with a constant velocity and multi-highlights. The velocity estimation performance is analyzed though the signal’s matched filter and the wideband ambiguity function. An improved method based on the sliding window matching algorithm is proposed to improve the performance. The method controls the energy of environmental noise and interference by focusing on the dominant target highlight, and applying a designed window which utilizes the Doppler characteristics of hyperbolic-frequency modulated signals. Simulations and lake experiment allow us to compare between the improved method and the conventional matched filter method. The results verify the influence of the multi-highlights in velocity estimation and indicate that the improved method has more effective performance.

scholarly journals Research on Turning Motion Targets and Velocity Estimation in High Resolution Spaceborne SAR

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2201 ◽  
Author(s):  
Xuejiao Wen ◽  
Xiaolan Qiu
Keyword(s):  
High Resolution ◽  
Geometric Modeling ◽  
Phase Error ◽  
Estimation Method ◽  
Velocity Estimation ◽  
Continuous Change ◽  
Straight Line ◽  
Moving Direction ◽  
Turning Motion ◽  
Motion Imaging

The development of high resolution SAR makes the influence of moving target more prominent, which results in defocusing and other unexplained phenomena. This paper focuses on the research of imaging signatures and velocity estimation of turning motion targets. In this paper, the turning motion is regarded as the straight line motion of continuous change of moving direction. Through the analysis of the straight line motion with constant velocity and the geometric modeling of the turning motion in spaceborne SAR, the imaging signatures of the turning motion target are obtained, such as the broken line phenomenon at the curve. Furthermore, a method for estimating the turning velocity is proposed here. The radial velocity is calculated by the azimuth offset of the turning motion target and the azimuth velocity is calculated by the phase error compensated in the refocusing process. The amplitude and direction of the velocity can be obtained by using both of them. The results of simulation and GF-3 data prove the accuracy of the analysis of turning motion imaging signatures, and they also show the accuracy and validity of the velocity estimation method in this paper.

A Robust Radial Velocity Estimation Method for FDA-SAR

2020 ◽  
Vol 17 (4) ◽  
pp. 646-650
Author(s):  
Yifan Guo ◽  
Guisheng Liao ◽  
Qingjun Zhang ◽  
Jun Li ◽  
Tong Gu
Keyword(s):  
Radial Velocity ◽  
Estimation Method ◽  
Velocity Estimation

scholarly journals Improved Shear Wave Group Velocity Estimation Method Based on Spatiotemporal Peak and Thresholding Motion Search

2017 ◽  
Vol 64 (4) ◽  
pp. 660-668 ◽  
Author(s):  
Carolina Amador Carrascal ◽  
Shigao Chen ◽  
Armando Manduca ◽  
James F. Greenleaf ◽  
Matthew W. Urban
Keyword(s):  
Group Velocity ◽  
Shear Wave ◽  
Estimation Method ◽  
Velocity Estimation ◽  
Wave Group ◽  
Motion Search
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