Many efforts have been taken in recent years to push atomic gravimeters toward practical applications. We demonstrate an gravimeter named NIM-AGRb2 that is transportable and suitable for high-precision gravity measurements. Constraint-structured active vibration isolation (CS-AVI) used reduce the ground noise. The constraint structure CS-AVI ensures platform only has vertical translation, with all other degrees of freedom (DoFs) being constrained. Therefore, stability enhanced. With...

Satellite data is of high importance for ocean environment monitoring and protection. However, due to the missing values in satellite data, caused by various force majeure factors such as cloud cover, bad weather sensor failure, quality reduced greatly, which hinders applications practice. Therefore, a variety methods have been proposed conduct imputation improve its quality. these cannot well learn short-term temporal dependence dynamic spatial resulting performance when rate large. To...

The absolute gravimeter plays an important role in metrology, geophysics, and geological exploration. Seismic environmental vibration has been one of the most serious factors limiting its performance. Consequently, ultralow-frequency vertical isolator is required to significantly improve measurement precision. A novel active employing geometric antispring (GAS) structure proposed this paper. payload supported by a GAS fixed on inner frame, frame hung coil springs from base. relative movement...

Absolute gravimeter has played an important role in geophysics, metrology, geological exploration, etc. It is instrument applying laser interferometry or atom to the measurement of gravitational acceleration <i>g</i> (approximately 9.8 m/s<sup>2</sup>). To achieve a high accuracy, vibration correction method often employed reduce influence reference object (a retro-reflector mirror) on result absolute gravimeter. Specifically, atomic-interferometry gravimeter, phase...

Classical absolute gravimeters are widely used in many areas, including metrology, seismology, geophysics, and exploration. These apply a free-fall method to measure gravitational acceleration using laser interferometer. In practice, the measurement precision is affected by ground vibrations. Vibration correction an important way deal with these vibrations for gravity measurement. Most vibration methods use commercial seismometer motion of reference retroreflector indirectly. A vertical...

For absolute gravimeters, which play important roles in geophysics and geological exploration, an ultra-low-frequency vertical vibration isolator is necessary to achieve the required measurement precision. A novel active that uses a geometric anti-spring (GAS) structure has been proposed by our team at Tsinghua University previously, but its performance mainly limited large-scale drift detection signal of system. In this paper, after brief theoretical introduction overall system, recent...

The morphology of many insect species is usually influenced by environmental factors and therefore high phenotypic variation exists even within a species. This causes difficulty uncertainty in taxonomy, which can be remedied using molecular data integrative taxonomy. Astegopteryxbambusae A.bambucifoliae are currently regarded as two closely related aphid with similar bamboo hosts overlapping distributions the oriental region. However, practice it hard to distinguish between them. By...

Free-fall absolute gravimeters are widely employed to measure the gravitational acceleration, commonly known as g. It applies an interferometer trajectory of a free-falling object. The measurement precision is limited by ground vibration. A vibration correction method often applied in noisy environment including moving platform, sometimes it required get g value quickly. takes much time about 6 min calculate for one set (no less than 25 drops). In order quickly and accurately obtain hostile...

Vibration isolators have been widely used to keep the target object from ground vibration in order improve measurement accuracy. Nowadays, ultra-low frequency isolator based on a two-stage structure shows best performance. Traditionally, vertically suspended springs are usually applied as second-stage. As requirement of low stiffness, need be long, which brings disadvantages relatively large size and small allowable load. A novel active vertical is proposed this paper, applies geometric...

A free-fall absolute gravimeter uses a Mach-Zehnder interferometer to track the free-falling object. Theoretically, it needs an inertial reference point, which is retroreflector keeping static in frame for accurate gravimetry. Practically, always disturbed by ground vibration. Traditionally, vibration correction method with broadband seismometer used reduce effect of The transfer function between and hypothesized as proportional element time delay. difference real limits correction. On this...

Abstract The ballistic free-fall absolute gravimeters are widely used in acquiring information of gravity field and the self-vibration gravimeter is crucial for high precision gravitational measurement. T-1 has a multi-directional full-band excitation. resulted horizontal swing major impact, since simplified as cantilever beam. A laser vibrometer was applied to directly measure mechanical self-vibration. frequency nonlinear effect on measurement error g, peak frequencies should be avoided....

A classical absolute gravimeter is widely used to measure the gravitational acceleration, normally known as g. It applies a Mach-Zehnder interferometer track free-falling retroreflector in vacuum chamber. Theoretically, it needs static reference an inertial frame. Practically, always disturbed by ground vibration. Vibration correction methods apply seismometer output calculate motion of retroreflector. Transfer function between them hypothesized approach real transfer function. The error...

With the expansion of network scale, traditional routing strategies in Software-Defined Networking (SDN) have difficulty adapting to fast traffic variability. The large flow occupies 80% traffic. An unreasonable schedule will lead emergence bottleneck links and reduce performance. To solve above problems, this paper proposes a different method, called Routing Strategy for SDN Large Flow Based on Deep Reinforcement Learning (RSDRL). Considering that can carry are limited, RSDRL firstly...

Absolute gravimeter, an instrument which is applied to laser interferometry or atom for measuring the gravitational acceleration <i>g</i> (approximately 9.8 m/s<sup>2</sup>), plays important role in metrology, geophysics, geological exploration, etc. To achieve a high accuracy of several microGals (μGal, 1μGal = 1 × 10<sup>–8</sup> vertical vibration isolator widely employed absolute gravimeter protect reference object (a retro-reflector mirror) from being...

Abstract Absolute gravimeters have been widely used as an important instrument in geological exploration and geophysics. To achieve a required measurement precision, it is necessary to integrate vertical vibration isolator with ultra-low resonance frequency into the gravimeter. In this paper, active designed on basis of BM-10 passive isolation platform presented. isolator, seismometer placed next payload same plate outputs voltage signal proportional payload’s velocity. According signal,...

When the cam-driven absolute gravimeter is used for gravity measurements, displacement generated by vibration of retroreflector couples into laser interference fringe signal. It severely affects accuracy measurements. Therefore, a time-frequency analysis method based on parametric optimization variational mode decomposition-Wigna Ville distribution proposed. The signals measured reference are decomposed adaptively to obtain each frequency band, and studied from perspective spectrum. At same...

High-precision absolute determinations of gravitational acceleration g provide important data for many fields such as metrology, geophysics, and geological exploration. In gravimetry, vibrational noise from seismic other environmental disturbances is one the limiting factors. Several types ultra-low vertical vibration isolators have been developed in Tsinghua University. The first a passive isolator based on LaCoste spring linkage can achieve natural period up to 32 s. second an active...

Abstract Free-fall absolute gravimeters are important classical high precision in many branches of scientific research. But its performance is always troubled by the ground vibration. Vibration correction method used to correct result detecting vibration with sensors. A Kalman filter based fusion proposed obtain more accurate signal fusing outputs seismometer and accelerometer. Experiment conducted homemade T-1 gravimeter, standard deviation corrected results using data fused 586.32 μGal (1...