scholarly journals Efficient Bi-Iterative Method for Source Position and Propagation Speed Estimation Using TDOA Measurements

2014 ◽  
Vol 10 (12) ◽  
pp. 689871 ◽  
Author(s):  
Guo-Hui Zhu ◽  
Da-Zheng Feng ◽  
Yan Zhou
Keyword(s):  
Iterative Method ◽  
Propagation Speed ◽  
Speed Estimation ◽  
Source Position

scholarly journals Accurate three-step algorithm for joint source position and propagation speed estimation

2007 ◽  
Vol 87 (12) ◽  
pp. 3096-3100 ◽  
Author(s):  
Jun Zheng ◽  
Kenneth W.K. Lui ◽  
H.C. So
Keyword(s):  
Propagation Speed ◽  
Speed Estimation ◽  
Source Position ◽  
Step Algorithm

scholarly journals Internal solitary waves propagation speed estimation in the northern-part of Lombok Strait observed by Sentinel-1 SAR and Himawari-8 images

2021 ◽  
Vol 944 (1) ◽  
pp. 012042
Author(s):  
Chonnaniyah ◽  
I W G A Karang ◽  
T Osawa
Keyword(s):  
Optical Sensors ◽  
Propagation Speed ◽  
High Temporal Resolution ◽  
Speed Estimation ◽  
Remotely Sensed Data ◽  
Tidal Period ◽  
Simple Estimation ◽  
Waves Propagation ◽  
Image Pairs ◽  
Wide Swath

Abstract Remotely sensed data, both Synthetic Aperture Radar (SAR) and optical sensors, significantly contribute to the study and understanding internal solitary wave (ISW) dynamics in the ocean. Pairs of SAR and optical sensors were analyzed to estimate the ISW propagation speed in the northern-part of Lombok Strait. ISW propagation speed estimation used an image from Sentinel-1 SAR and three image pairs of Himawari-8 on 29 October 2018 with a time difference of 409 minutes. Sentinel-1 wide-swath imagery (250 km x 400 km) from two adjacent scenes can provide information on multiple ISW packets evolution in the northern-part of Lombok Strait. ISW propagation speed estimation on Sentinel-1 SAR image using the simple estimation by measuring the interpacket distance and dividing by the semidiurnal tidal period. The high temporal resolution of the optical sensor from Himawari-8 can estimate the ISW propagation speed using two different approaches. ISW propagation speed estimation using the semidiurnal tidal period from Sentinel-1 and Himawari-8 showed almost similar values. Sentinel-1 estimation results are 2.69 m.s−1 (Lombok Strait) and 1.30 m.s−1 (northern-part area), Himawari-8 results are 2.52 m.s−1 (Lombok Strait) and 1.27 m.s−1 (northern-part area). ISW propagation speed variability in the northern-part of the Lombok Strait shown in this study.

Development of a conical anode Fe-gun for low voltage SEM

1988 ◽  
Vol 46 ◽  
pp. 978-979
Author(s):  
T. Miyokawa ◽  
S. Norioka ◽  
S. Goto
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Low Voltage ◽  
Irradiation Damage ◽  
Cold Cathode ◽  
Virtual Source ◽  
Source Position ◽  
Electrostatic Lens ◽  
Electrostatic Lenses ◽  
Wide Range

Field emission SEMs (FE-SEMs) are becoming popular due to their high resolution needs. In the field of semiconductor product, it is demanded to use the low accelerating voltage FE-SEM to avoid the electron irradiation damage and the electron charging up on samples. However the accelerating voltage of usual SEM with FE-gun is limited until 1 kV, which is not enough small for the present demands, because the virtual source goes far from the tip in lower accelerating voltages. This virtual source position depends on the shape of the electrostatic lens. So, we investigated several types of electrostatic lenses to be applicable to the lower accelerating voltage. In the result, it is found a field emission gun with a conical anode is effectively applied for a wide range of low accelerating voltages.A field emission gun usually consists of a field emission tip (cold cathode) and the Butler type electrostatic lens.

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