Gravitational Satellite Research Articles

Estimations of the Geothermal Energy Potential in The Mount Anak Krakatau Region Based on Derivative Analysis and 3D Model of Gravitational Satellite Data

Geothermal energy is a source of renewable energy that has the potential to be produced, considering that Indonesia is in the ring of fire, where there are many volcanoes, one of which is Mount Anak Krakatau. Even though direct exploration is not permitted, at least information on the geothermal system on the mountain can still be obtained using satellite data. Therefore, this study aims to analyze the geothermal energy potential of Mount Anak Krakatau using gravity satellite data with a total of 320 data consisting of gravity disturbance, geoid, and Digital Elevation Model. The data processing describes a 3D model that is correlated with the First Horizontal Derivative (FHD) and Second Vertical Derivative (SVD) analysis. Based on the results of the residual anomaly map analysis, the low anomaly has a value of -1.85–(-0.89) mGal which is suspected to be associated with magma pockets, and the high anomaly ranges from 0.04–2.13 mGal which is suspected to be associated with the caldera of Mount Anak Krakatau. Based on the results of the FHD and SVD graphical analysis, there are 18 faults that control the geothermal system. Based on the results of 3D modeling trending from west-east it can be seen that there is a clay cap layer with a value density 2.32–2.37 gr/cc at depths of 0–550 m and reservoir layers with density values of 2.23–2.29 gr/cc at depths of 500–1100 m. This geothermal research using the gravity method can be developed and become a reference for future research to calculate the potential for electrification in a research area.

A Comparison of Orthometric Heights Calculated from (GPS/Leveling) and (EGM08) Methods Based–GIS

Interest in the study of global gravitational models has increased recently all over the world because it is necessary for height datum transformations. Today the International Center for Global Earth Models (ICGEM) provides the largest collection in the world produced through gravitational data from the gravitational satellite’s missions CHAMP, GRACE, and GOCE … Etc. To allow easy access through the internet with its more intelligent technologies, it is one of the International Gravity Organization’s services. While the Global Positioning System (GPS) has become one of the most preferred technologies in engineering surveying, a major dilemma in GPS survey lies in oval-based elevations. At the same time, orthometric heights are commonly used in the engineering field. Therefore, it is necessary to convert the measured heights by satellites assigned to the elliptical surface into orthometric heights and supported to the geoid surface (mean sea level) through an accurate geodetic model. The differences between orthometric measurement heights from DGPS/leveling data (obtained from 57 points in the study area) are increasingly used by professionals geographical information systems(GIS). However, the local determination of Geoid is necessary for better accuracy of the orthometric height from DGPS. This paper aims to introduce a modern technique for determining elevation, avoiding cumbersome and time-consuming spirit leveling operations. Fast vertical positioning can be obtained using DGPS with geoid models. The Root Mean Square Error (RMSE) is ± 0.19 m with high precision of DGPS derived with EGM08; thus, the more it describes the Earth’s gravitational field in more detail.

Application of the GRACE satellite mission for solving geological and geographic problems

In this paper we provide a literature review of the geological and geographic problems that were successfully solved via the application of the Gravity Recovery And Climate Experiment (GRACE) satellite mission data. GRACE is a gravitational satellite mission whose purpose is the precise mapping of variations of the Earth’s gravity field. The data have high resolution, which provides the opportunity to solve many geological and geographical problems.

GRACE application for geological and geographical problems

In this article we provide the literature review of the geological and geographical problems which were successfully solved due to application of GRACE satellite mission data. GRACE (Gravity Recovery And Climate Experiment) is gravitational satellite mission the purpose of which is precise mapping of variations of Earth’s gravity field. The data has high resolution that gives the opportunity to solve a lot of geological and geographical problems.

Numerical integration of relativistic equations of motion for Earth satellites

The equations of motion proposed by Brumberg for an artificial satellite around the Earth (Celest Mech Dyn Astron 88:209, 2004), in which the relativistic effects due to the Earth’s oblatness and the gravitational action caused by a third body are added to those perturbations considered in the International Earth Rotation and Reference System Service (2003) convention, are here integrated numerically. To compute the solution of the time-dependent Langrangian system for a gravitational satellite–Earth–Sun model we consider a six-order partitioned Runge–Kutta integrator, whose coefficients satisfy the condition of symplecticity. A comparison with the classical Adams–Basforth–Moulton method allows to verify the good-performance of the partitioned Runge–Kutta method both in the description of the evolution of the satellite energy and in the efficiency of the method when applied to a long-term integration.

Recovery of long-wavelength mean gravity anomalies for the dedicated gravitational satellite (gravsat) mission

This paper describes a computer simulation study that was undertaken to determine how well long-wavelength variations in the Earth's gravitational field can be recovered using data from the Dedicated Grav itational Sat ellite (GRAVSAT) mission. This mission is to consist of two low altitude (160 km) spacecraft in essentially the same orbit but separated in phase by 100–300 km. Geodetic data are measurements of the relative range rate to an accuracy of about 1 μm/s at 4 sec intervals. Specifically, a Bayesian covariance simulation was used to investigate simultaneous recovery of the spacecraft ephemerides and a global distribution of 20° × 20° mean gravity anomaly blocks. Sources of errors considered were tracking station positions, gravitational constant, Earth body tides, tropospheric modeling and measurement noise. It should be noted that this simulation does not include as an error source variations in the gravity field that have a character different from what was modeled. Consequently, this study demonstrates the potential of the low-low system as configured to recover the long-wavelength variations in the gravity field. Using only one days worth of data, the mean of the standard deviations of the 162 20° × 20° gravity anomaly blocks is about 1 μgal. For a 6 month mission (assuming a reduction proportional to the square root of the data intervals) this projects to < 0.1 μgal. Because of the potential of increased measurement precision at shorter separation distances, and the relative insensitivity of the recovery process to separation distance, it should be possible to recover both long and short wavelength variations with a modest distribution of separation distances tailored primarily to the short wavelength recovery. Effects of the uncertainty in the gravitational constant and Love's numbers are negligible. In a simulation not reported on, increasing the altitude of the orbit to 200 km from 150 km, degraded, as expected, the accuracy of the recovered parameters by only 7%.

Description of the Dedicated Gravitational Satellite Mission (GRAVSAT)

A description of the dedicated gravitational satellite (GRAVSAT) mission is presented. Scientific objectives are to substantially improve our knowledge of solid earth geophysics and oceanography by determining a more accurate geopotential. The most stringent requirement is determination of mean gravity anomalies over regions- 100-km square to an accuracy of 2.5 mgal (1 gal = 1 cm/s2). Fundamental geodetic data will be satellite-to-satellite measurement of relative range rate. Orbital characteristics are discussed. An error budget is presented which indicates that the requisite measurement precision can be achieved by closed-loop RF doppler measurements. Implicit in the discussion of the error budget is a description of the spacecraft and systems components.

Applications of a dedicated gravitational satellite mission

In 1978, the National Aeronautics and Space Administration (NASA) asked the National Research Council, through the Committee on Geodesy, to conduct a workshop on the applications of a dedicated gravitational satellite mission. Such a mission had been recommended in the report, Geodesy: Trends and Prospects, subject to the analysis of accuracy requirements and feasibilities. The workshop was organized through the Panel on Gravity Field and Sea Level, chaired by John C. Harrison. His co‐chairman was Richard H. Rapp.

Equations of rotational motion of a gravitational satellite equipped with deformable stabilizers

Equations of rotational motion of a gravitational satellite equipped with deformable stabilizers