scholarly journals A High-Precision Magnetic Induction Through-the-Earth Positioning Scheme

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 35109-35120
Author(s):  
Wenlong Tian ◽  
Wei Yang ◽  
Xiaotao Shao
Keyword(s):  
High Precision ◽  
Magnetic Induction ◽  
The Earth

INVESTIGATION OF THE ABSOLUTENESS OF TIME

2021 ◽  
pp. 51-54
Author(s):  
S. Tiguntsev
Keyword(s):  
High Precision ◽  
Gravitational Potential ◽  
High Speed ◽  
Relativistic Effect ◽  
Theoretical Research ◽  
Clock Frequency ◽  
Positioning Systems ◽  
The Earth ◽  
Flow Of Time ◽  
The Difference

In classical physics, time is considered absolute. It is believed that all processes, regardless of their complexity, do not affect the flow of time The theory of relativity determines that the flow of time for bodies depends both on the speed of movement of bodies and on the magnitude of the gravitational potential. It is believed that time in space orbit passes slower due to the high speed of the spacecraft, and faster due to the lower gravitational potential than on the surface of the Earth. Currently, the dependence of time on the magnitude of the gravitational potential and velocity (relativistic effect) is taken into account in global positioning systems. However, studying the relativistic effect, scientists have made a wrong interpretation of the difference between the clock frequency of an orbiting satellite and the clock frequency on the Earth's surface. All further studies to explain the relativistic effect were carried out according to a similar scenario, that is, only the difference in clock frequencies under conditions of different gravitational potentials was investigated. While conducting theoretical research, I found that the frequency of the signal changes along the way from the satellite to the receiver due to the influence of Earth's gravity. It was found that the readings of two high-precision clocks located at different heights will not differ after any period of time, that is, it is shown that the flow of time does not depend on the gravitational potential. It is proposed to conduct full-scale experiments, during which some high-precision clocks are sent aboard the space station, while others remain in the laboratory on the surface of the earth. It is expected that the readings of the satellite clock will be absolutely identical to the readings of the clock in the Earth laboratory.

scholarly journals Evaluation of global ocean tide models based on tidal gravity observations in China

2020 ◽  
Author(s):  
Hongbo Tan ◽  
Chongyong Shen ◽  
Guiju Wu
Keyword(s):  
High Precision ◽  
Earth Tide ◽  
Global Ocean ◽  
Ocean Tide ◽  
Ocean Tides ◽  
Ocean Tide Model ◽  
Tidal Forces ◽  
The Earth ◽  
Gravity Observation ◽  
Ocean Tide Models

<p>Solid Earth is affected by tidal cycles triggered by the gravity attraction of the celestial bodies. However, about 70% the Earth is covered with seawater which is also affected by the tidal forces. In the coastal areas, the ocean tide loading (OTL) can reach up to 10% of the earth tide, 90% for tilt, and 25% for strain (Farrell, 1972). Since 2007, a high-precision continuous gravity observation network in China has been established with 78 stations. The long-term high-precision tidal data of the network can be used to validate, verifying and even improve the ocean tide model (OTM).</p><p>In this paper, tidal parameters of each station were extracted using the harmonic analysis method after a careful editing of the data. 8 OTMs were used for calculating the OTL. The results show that the Root-Mean-Square of the tidal residuals (M<sub>0</sub>) vary between 0.078-1.77 μgal, and the average errors as function of the distance from the sea for near(0-60km), middle(60-1000km) and far(>1000km) stations are 0.76, 0.30 and 0.21 μgal. The total final gravity residuals (Tx) of the 8 major constituents (M<sub>2</sub>, S<sub>2</sub>, N<sub>2</sub>, K<sub>2</sub>, K<sub>1</sub>, O<sub>1</sub>, P<sub>1</sub>, Q<sub>1</sub>) for the best OTM has amplitude ranging from 0.14 to 3.45 μgal. The average efficiency for O<sub>1</sub> is 77.0%, while 73.1%, 59.6% and 62.6% for K<sub>1</sub>, M<sub>2</sub> and Tx. FES2014b provides the best corrections for O<sub>1</sub> at 12 stations, while SCHW provides the best for K<sub>1 </sub><sub>,</sub>M<sub>2</sub>and Tx at 12,8and 9 stations. For the 11 costal stations, there is not an obvious best OTM. The models of DTU10, EOT11a and TPXO8 look a litter better than FES2014b, HAMTIDE and SCHW. For the 17 middle distance stations, SCHW is the best OTM obviously. For the 7 far distance stations, FES2014b and SCHW model are the best models. But the correction efficiency is worse than the near and middle stations’.</p><p>The outcome is mixed: none of the recent OTMs performs the best for all tidal waves at all stations. Surprisingly, the Schwiderski’s model although is 40 years old with a coarse resolution of 1° x 1° is performing relative well with respect to the more recent OTM. Similar results are obtained in Southeast Asia (Francis and van Dam, 2014). It could be due to systematic errors in the surroundings seas affecting all the ocean tides models. It's difficult to detect, but invert the gravity attraction and loading effect to map the ocean tides in the vicinity of China would be one way.</p>

scholarly journals Regular reversals in the six-jet geodynamo model

2018 ◽  
Vol 62 ◽  
pp. 02014
Author(s):  
Liubov Feshchenko
Keyword(s):  
Magnetic Field ◽  
Magnetic Induction ◽  
The Core ◽  
The Earth ◽  
Free Decay ◽  
Regular Character

A low-mode geodynamo model is developed, controlled by 6-jet convection in the core of the Earth. The model contains only four modes, representing the fields of temperature, velocity, and two fields of magnetic induction. The magnetic modes was chosen by combining eight magnetic modes of free decay. There are two noise components in the model. In the model, stable regimes of generation of a magnetic field with reversals having a regular character were obtained. These reversals do not cause changes in the convection structure.

DECIGO PATHFINDER

2013 ◽  
Vol 22 (01) ◽  
pp. 1341002 ◽  
Author(s):  
MASAKI ANDO ◽  
the DECIGO WORKING GROUP
Keyword(s):  
Black Hole ◽  
Gravitational Wave ◽  
Conceptual Design ◽  
High Precision ◽  
Precision Measurements ◽  
Current Status ◽  
The Earth ◽  
Future Space

DECIGO Pathfinder (DPF) is a small (~350 kg) satellite orbiting the Earth. DPF was originally proposed as the first milestone mission for a future space gravitational-wave (GW) antenna, DECi-hertz Interferometer Gravitational wave Observatory (DECIGO). In addition to the purpose of space demonstrations for DECIGO, DPF has scientific objectives: observation of GWs from black-hole mergers and monitor of Earth's gravity, as well as establishment of space technologies for high-precision measurements. In this paper, we review the conceptual design, scientific outcomes and the current status of DPF.

Results of Spectrograph EMILIE with the AAA System on Solar-Like Oscillations

2002 ◽  
Vol 185 ◽  
pp. 472-473 ◽  
Author(s):  
F. Bouchy ◽  
J. Schmitt ◽  
J.-L. Bertaux ◽  
P. Connes
Keyword(s):  
Systematic Error ◽  
High Precision ◽  
Reference Spectrum ◽  
The Sun ◽  
The Earth ◽  
The Absolute

The spectrograph EMILIE (Bouchy et al., 1999; Bouchy, 1999; Bouchy et al., 2000) coupled to the Absolute Astronomical Accelerometer (AAA, Connes, 1985; Schmitt, 1997) and implemented at the 152-cm Coudé telescope of the Observatoire de Haute Provence is dedicated to high-precision Doppler measurements. The AAA method uses a sliding reference spectrum constrained to track the stellar lines and to use the spectrograph as a null-checking device. The goal of AAA is to eliminate the calibration of the spectrograph as well as the displacement of the spectra across the CCD pixels due to the earth motion (and suspected to introduce a systematic error in the RV measurement). Here we report seismological results obtained with AAA on the Sun and the bright stars Procyon and ζ Her A that are expected to present solar-like oscillations.

scholarly journals Analysis of Distributed Measurement Method for Array Antenna Position

2020 ◽  
Vol 10 (10) ◽  
pp. 3480
Author(s):  
Zhen Ma ◽  
Xiyuan Chen
Keyword(s):  
High Precision ◽  
Measurement Method ◽  
Earth Observation ◽  
Array Antenna ◽  
Observation System ◽  
Phase Center ◽  
The Earth ◽  
Earth Observation System ◽  
Distributed Measurement ◽  
Antenna Position

The measurement of the phase center of the airborne array antenna can directly affect the accuracy of the Earth observation system. However, the relationship between the relative motion of each sub-antenna cannot be accurately measured because of the adverse environment of the airborne platform. Therefore, it is necessary to find a suitable method to measure the motion parameters of distributed antennas and the phase center of each element antenna accurately in order to improve the imaging resolution of the Earth observation system. Distributed position and orientation system (POS) technology has high precision, but its measurement error will accumulate with time. So it needs to transfer and align continuously to achieve high-precision measurement. The paper introduces the distributed measurement method of measuring the array antenna position based on the combination of fiber Bragg grating (FBG) sensing technology and POS technology on the aircraft wing. The paper first introduces the technical scheme and principle, then carries out the structural design and method analysis. Next, the structural strength of the experimental model is checked and summarized.

scholarly journals The Reference Frame Determined From the Observation of Minor Planets by Hipparcos

1990 ◽  
Vol 141 ◽  
pp. 329-336
Author(s):  
B. Morando ◽  
A. Bec-Borsenberger
Keyword(s):  
Reference Frame ◽  
High Precision ◽  
Reference System ◽  
Initial Position ◽  
Minor Planet ◽  
Minor Planets ◽  
The Moon ◽  
Phase Effect ◽  
The Earth ◽  
A Minor

The observation of minor planets by Hipparcos offers the opportunity to obtain high precision positions for some minor planets. About fifty minor planets are on the programme. Their ephemerides had to be improved in order to reach a precision of 1 arsec and occultations by the Earth and the Moon had to be predicted.From the position of a minor planet on reference great circles at different times better values of the initial position and velocity will be deduced but the reduction of the observations of the minor planets have to take into account the displacement of the photocentre relative to the centre which is due to the shape, the phase effect and the scattering properties of the surface. For some very small planets considered as star like this diplacement will be small and the precise positions obtained will allow to position the dynamical reference system relative to the Hipparcos system. For the bigger minor planets the observations by Hipparcos may give informations on the shape and scattering properties of the surface.

A Discussion on the measurement and interpretation of changes of strain in the Earth - New Zealand Earth strain measurements

1973 ◽  
Vol 274 (1239) ◽  
pp. 311-321 ◽  
Keyword(s):  
New Zealand ◽  
High Precision ◽  
Heavy Rain ◽  
Great Care ◽  
Strain Measurements ◽  
Exposed Site ◽  
The Earth

Three invar wire lever type Earth strain meters are being operated in geophysically interesting areas in New Zealand. T he oldest has been operational since early 1970. The main object of the work has been to detect possible strain changes occurring before an earthquake. None have been detected, the most likely earthquake to have produced an effect before hand having M s = 5.3 and lying at A = 1° from the nearest strain meter. Strain steps accompanying earthquakes appear to be rather smaller than expected. A great deal of information has been accumulated on strains induced by wind and rain at the most exposed site which is but 10 m below the top of a very exposed 300 m hill. Strain changes produced by several days’ heavy rain can, at this site, be as m uch as 3 x 10-6, and this indicates th at great care m ust be taken in interpreting apparent changes in the length of a baseline m easured by high precision surveying.

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