Seismic Wave Detection based on Laser Interferometer for P-S Time Measurement

In this paper, we propose a seismic wave detection process using a laser interferometer as a seismometer. The laser interferometer system is an important equipment with its remarkable accurate capability for displacement measurement. During the process of the seismic wave measurement, however, environmental and nonlinearity error are occurred in a heterodyne laser interferometer. Through the extended Kalman filter compensation, the distortion is reduced. With a recursive STA/LTA algorithm, the PS-time of the seismic wave is determined and then the epicenter distance can be derived. Through some simulations, it is demonstrated that the proposed algorithm can reduce error factors and improve the measurement accuracy of a seismometer.

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Small-Sized Interferometer with Fabry–Perot Resonators for Gravitational Wave Detection

Sensors ◽

10.3390/s21051877 ◽

2021 ◽

Vol 21 (5) ◽

pp. 1877

Author(s):

Nikolai Petrov ◽

Vladislav Pustovoit

Keyword(s):

Correlation Function ◽

Gravitational Waves ◽

Laser Interferometer ◽

Zero Order ◽

Wave Detection ◽

Resonant Modes ◽

Fabry Perot ◽

Spatially Distributed ◽

Wave Laser ◽

Higher Sensitivity

It is highly desirable to have a compact laser interferometer for detecting gravitational waves. Here, a small-sized tabletop laser interferometer with Fabry–Perot resonators consisting of two spatially distributed “mirrors” for detecting gravitational waves is proposed. It is shown that the spectral resolution of 10−23 cm−1 can be achieved at a distance between mirrors of only 1–3 m. The influence of light absorption in crystals on the limiting resolution of such resonators is also studied. A higher sensitivity of the interferometer to shorter-wave laser radiation is shown. A method for detecting gravitational waves is proposed based on the measurement of the correlation function of the radiation intensities of non-zero-order resonant modes from the two arms of the Mach–Zehnder interferometer.

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Study on the Location Method Based on Seismic Wave Detection

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.229-231.2038 ◽

2012 ◽

Vol 229-231 ◽

pp. 2038-2041 ◽

Cited By ~ 1

Author(s):

Chao Xiong ◽

Bing Wen Zhang ◽

Li Zhang ◽

Chun Ting Ma

Keyword(s):

High Precision ◽

Seismic Wave ◽

Azimuth Angle ◽

Time Delay Estimation ◽

Delay Estimation ◽

Location Method ◽

Wave Detection ◽

Seismic Sensors ◽

Array Structure ◽

Square Array

A location method based on seismic wave detection was put forward. The seismic wave was collected by high-precision seismic sensors which were set as five-element-square-array structure. The distance and azimuth angle were acquired according to the time delay estimation between each sensor. The result of experiment shows that the location method is effective and has a high precision.

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TDC Implementation Based on Internal Delay Module of FPGA

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.816-817.1063 ◽

2013 ◽

Vol 816-817 ◽

pp. 1063-1068

Author(s):

Rou Gang Zhou ◽

Yun Fei Zhou ◽

Guang Dou Liu ◽

Xiao Tu

Keyword(s):

Nuclear Physics ◽

Measurement Accuracy ◽

Laser Interferometer ◽

Interpolation Method ◽

Time Measurement ◽

Clock Signal ◽

Signal Delay ◽

Digital Conversion ◽

Sampling Points ◽

Stable Performance

Currently the time to digital converter (TDC) integrated in FPGA performs time-to-digital conversion in the carry chain mode and inter-slot offset is caused to be severe by internal wiring in the FPGA. Based on the carry chain interpolation method, this paper proposes the method for using a delay module in FPGA to achieve accurate signal delay. By calculating the phase difference of multi-clock signal between two latch sampling points, the interval between two sampling points was obtained. Experimental results indicate a measurement accuracy of 78ps or 52ps can be reached by precisely collecting time through the delay module in FPGA. Compared to the carry chain interpolation method, this method is significantly advantageous in small inter-slot offset, stable performance and convenient design and can meet the requirement for time measurement or requirement by laser interferometer with a nm-level accuracy in nuclear physics.

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Key technologies analysis and design of ultra-clean & ultra-stable spacecraft for gravitational wave detection

International Journal of Modern Physics A ◽

10.1142/s0217751x21400212 ◽

2021 ◽

pp. 2140021

Author(s):

Kun Chen ◽

Xiaofeng Zhang ◽

Tong Guo ◽

Zhi-Ming Cai ◽

Keyword(s):

Gravitational Wave ◽

Measurement Accuracy ◽

Laser Interferometer ◽

Gravitational Interaction ◽

Thermal Control ◽

Theory Of Relativity ◽

Gravitational Wave Detection ◽

Analysis And Design ◽

Wave Detection ◽

Key Technologies

The observation of gravitational wave enables human to explore the origin, formation and evolution of universe governed by the gravitational interaction and the nature of gravity beyond general theory of relativity. The groundbreaking discovery of Gravitational Wave by Laser Interferometer Gravitational-Wave Observatory provides a brand-new observation way. While detecting gravitational wave on ground is limited by noises and test scale, space detection is an optimized alternative to learn rich sources in range of 0.1 mHz–1 Hz. Considering the great significance of space gravitational wave detection, ESA proposed LISA project, CAS also proposed Taiji project. Due to the extremely weak gravitational wave signal and high measurement accuracy requirement, the spaceborne GW observation antenna is accomplished by three spacecrafts constitute isosceles triangle formation intersatellite interferometer. The arm length of the interferometer reaches millions of kilometers between them, and the measurement accuracy reaches pico-meter magnitude. There are many key technologies including pm magnitude space laser interferometer metrology, drag-free control using TM of Gravity Reference Sensor, [Formula: see text]N micro thruster, ultra-clean & ultra-stable spacecraft, etc. This paper focuses on key technologies of the ultra-clean & ultra-stable spacecraft, analyzing the design of mechanical, thermal control and magnetic clean. Moreover, it reports the preliminary results of the technological breakthrough.

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THE DETECTION OF GRAVITATIONAL WAVES

International Journal of Modern Physics D ◽

10.1142/s0218271896000102 ◽

1996 ◽

Vol 05 (02) ◽

pp. 101-150 ◽

Cited By ~ 6

Author(s):

L. JU ◽

D.G. BLAIR

Keyword(s):

Gravitational Waves ◽

Galaxy Formation ◽

Laser Interferometer ◽

New Materials ◽

Noise Sources ◽

Detector Performance ◽

Wave Detection ◽

New Methods ◽

Stochastic Background ◽

Improve Detector

This paper reviews the field of gravitational wave detection. The characteristics of gravitational waves and the possible sources of detectable waves are discussed. This includes a discussion of a new source, the stochastic background of cosmological gravitational waves from supernovae during the epoch of galaxy formation. Methods of using both resonant mass antennas and laser interferometer detectors are reviewed. Noise sources that limit detector sensitivity are summarised, while new methods, and new materials which can simplify and improve detector performance are described.

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