Probabilistic Reasoning and Inconsistency Identification in Graph-based Models

2021 ◽  
pp. 533-563
Author(s):  
Sebastian J. I. Herzig ◽  
Christiaan J. J. Paredis
Keyword(s):  
Probabilistic Reasoning ◽  
The Other ◽  
Elliptical Orbit ◽  
Ground Control ◽  
Martian Surface ◽  
Ground Station ◽  
Inconsistency Identification ◽  
Orbit Insertion

In 1998, the National Aeronautics and Space Administration (NASA) launched the Mars Climate Orbiter (MCO) as part of the Mars Surveyor ’98 program. Upon arrival at Mars, MCO was to enter an elliptical orbit around the planet. On the day of orbit insertion, ground control was able to track the spacecraft visually up to the point when it vanished behind the planet. Unfortunately, the spacecraft never reappeared on the other side. It was later discovered that the probe came too close to the planet, and crashed into the Martian surface. The cause? A previously undiscovered mismatch in the use of unit systems for performing certain calculations in parts of the ground station software [43].

Observations of the Earth’s resources

1969 ◽  
Vol 308 (1493) ◽  
pp. 173-182 ◽  
Keyword(s):  
Mineral Exploration ◽  
Geological Mapping ◽  
The Other ◽  
Ground Control ◽  
Great Contribution ◽  
Know How ◽  
Control Information ◽  
The World ◽  
The One ◽  
Effective Development

In attempting to present some observations on the kind of information on the Earth’s resources which may be obtained from spacecraft and space satellites, I think I should explain that I speak as a geographer with research interests in the field of biogeography/geobotany where I have been concerned with the use of vegetation in mineral exploration work and in the assessment of land potential for agricultural and other uses. In the course of this work I have come to appreciate major problems of regional or even continental dimensions and have become aware of the great potential offered by suitably equipped Earth resources satellites for providing information which would assist their solution. At the same time I have come to recognize the great contribution which Earth resources satellites can make in the fields of agriculture, forestry and conservation, topographical and geological mapping, hydrology, oceanography, land use and urban planning, to mention but a few. As a setting for my subsequent remarks I would like to state what I believe to be the relative positions of the U. S. A. and the U. S. S. R. on the one hand and this country and certain West European countries on the other with regard to the acquisition of information from Earth resources satellites. America and Russia have led the world in space research. They have the resources, the facilities and the technical know-how for placing spacecraft and satellites in orbit. For the effective development of Earth resources satellites, however, ground control information is essential. Here this country, together with member and former member countries of the Commonwealth possesses a body of people scattered through universities, government departments and organizations, commerce and industry whose firsthand knowledge of remote terrain in many parts of the world is unrivalled. This knowledge harnessed into an Earth resources satellites programme could enable this country to make a leading contribution to the development of the less developed parts of the world and at the same time materially assist the economy of this country.

scholarly journals The Double Star mission

2005 ◽  
Vol 23 (8) ◽  
pp. 2707-2712 ◽  
Author(s):  
Z. X. Liu ◽  
C. P Escoubet ◽  
Z. Pu ◽  
H. Laakso ◽  
J. K. Shi ◽  
...  
Keyword(s):  
Space Science ◽  
Double Star ◽  
The Other ◽  
Polar Orbit ◽  
Equatorial Orbit ◽  
Ground Station ◽  
Ground Segment ◽  
The Earth ◽  
Science Operations

Abstract. The Double Star Programme (DSP) was first proposed by China in March, 1997 at the Fragrant Hill Workshop on Space Science, Beijing, organized by the Chinese Academy of Science. It is the first mission in collaboration between China and ESA. The mission is made of two spacecraft to investigate the magnetospheric global processes and their response to the interplanetary disturbances in conjunction with the Cluster mission. The first spacecraft, TC-1 (Tan Ce means "Explorer"), was launched on 29 December 2003, and the second one, TC-2, on 25 July 2004 on board two Chinese Long March 2C rockets. TC-1 was injected in an equatorial orbit of 570x79000 km altitude with a 28° inclination and TC-2 in a polar orbit of 560x38000 km altitude. The orbits have been designed to complement the Cluster mission by maximizing the time when both Cluster and Double Star are in the same scientific regions. The two missions allow simultaneous observations of the Earth magnetosphere from six points in space. To facilitate the comparison of data, half of the Double Star payload is made of spare or duplicates of the Cluster instruments; the other half is made of Chinese instruments. The science operations are coordinated by the Chinese DSP Scientific Operations Centre (DSOC) in Beijing and the European Payload Operations Service (EPOS) at RAL, UK. The spacecraft and ground segment operations are performed by the DSP Operations and Management Centre (DOMC) and DSOC in China, using three ground station, in Beijing, Shanghai and Villafranca.

Speech Interface for Controlling Micro Air Vehicle

2020 ◽  
Vol 17 (1) ◽  
pp. 488-491
Author(s):  
P. Lakshmi ◽  
S. Veena ◽  
D. K. Rahul ◽  
H. Lokesha
Keyword(s):  
Natural Language ◽  
Language Processing ◽  
Automatic Speech Recognition ◽  
Micro Air Vehicle ◽  
The Other ◽  
Ground Control ◽  
Control Applications ◽  
Speech Interface ◽  
Air Vehicle ◽  
Ground Control Station

This paper focuses on the development of the speech interface for controlling a Micro Air Vehicle (MAV). A speech interface in such control applications will have two distinct modules. One is the Automatic Speech Recognition (ASR) module and the other is the Natural Language Processing (NLP) module. The ASR is developed using the models built using CMU Sphinx toolkit. The NLP scheme is proposed and developed using Natural Language Toolkit (NLTK). Understanding of the speech is very important in such kind of control applications. The NLP outcome is used to invoke the Ground Control Station (GCS) commands. The results are validated in a Flight Gear simulator using Mission Planner GCS configured for MAV.

Keyboard Design for UAV Ground Station Based on VC++ Multi-Thread Technology

2012 ◽  
Vol 630 ◽  
pp. 335-338
Author(s):  
Dong Li Yuan ◽  
Huan Li ◽  
Ao Xi ◽  
Zheng Ming Zhang ◽  
Jing Wei
Keyword(s):  
Remote Control ◽  
Serial Communication ◽  
Communication Protocols ◽  
The Other ◽  
Flight Velocity ◽  
Ground Station ◽  
Control Command ◽  
Main Thread

For the flight velocity of some UAV is high and the practice operation is much complex, the ground station keyboard based on multi-thread technology is designed. Also the keyboard is on the base of MSComm control in VC++ 6.0. There are two threads in this keyboard. According to the Serial Communication Protocols defined original the main thread accepts and transfers ground station command and GPS information. At the same time, the other thread scans matrix keyboard from which the UAV sends remote control command. The experiments testify that the keyboard can control UAV smoothly; meanwhile it is easy to operate for its simple configuration.

scholarly journals GEOREFERENCING ACCURACY ANALYSIS OF A SINGLE WORLDVIEW-3 IMAGE COLLECTED OVER MILAN

2016 ◽  
Vol XLI-B1 ◽  
pp. 429-434 ◽  
Author(s):  
L. Barazzetti ◽  
F. Roncoroni ◽  
R. Brumana ◽  
M. Previtali
Keyword(s):  
Bias Correction ◽  
Rational Functions ◽  
The Other ◽  
Ground Control ◽  
Control Points ◽  
Accuracy Analysis ◽  
Camera Model ◽  
Ground Control Points ◽  
High Resolution Satellite Imagery ◽  
Very High

The use of rational functions has become a standard for very high-resolution satellite imagery (VHRSI). On the other hand, the overall geolocalization accuracy via direct georeferencing from on board navigation components is much worse than image ground sampling distance (predicted < 3.5 m CE90 for WorldView-3, whereas GSD = 0.31 m for panchromatic images at nadir). <br><br> This paper presents the georeferencing accuracy results obtained from a single WorldView-3 image processed with a bias compensated RPC camera model. Orientation results for an image collected over Milan are illustrated and discussed for both direct and indirect georeferencing strategies as well as different bias correction parameters estimated from a set of ground control points. Results highlight that the use of a correction based on two shift parameters is optimal for the considered dataset.

scholarly journals Strain energy analysis of floor heave in longwall gateroads

2018 ◽  
Vol 5 (8) ◽  
pp. 180691 ◽  
Author(s):  
Meng Wang ◽  
Dongjie Zheng ◽  
Kewei Wang ◽  
Wenfeng Li
Keyword(s):  
Theoretical Model ◽  
Strain Energy ◽  
Energy Analysis ◽  
The Other ◽  
Ground Control ◽  
Yield Pillar ◽  
Floor Heave ◽  
Mining Safety ◽  
Energy Theory

Floor heave in longwall gateroads is a severe issue that affects mining safety and efficiency. Researchers, however, have limited understanding on the floor heave mechanism because the deformation of post-failure rocks in the floor was seldom considered previously. In this study, we developed a theoretical model using the strain energy theory to investigate the post-failure deformation of rocks. This model was validated before being implemented into a numerical modelling package, FLAC 3D , for floor heave analysis. Based on a case study of a longwall entry employing a stiff–yield pillar configuration, we observe that massive floor heave occurs at the entry rib that takes less loads (yield pillar) and eventually propagates towards the other rib bearing a significant amount of loads (stiff pillar). This observation sheds light on the floor heave mechanism in longwall gateroads and has major implications for coal mine ground control.

scholarly journals Physical Studies of Asteroids By Polarization of the Light

1971 ◽  
Vol 12 ◽  
pp. 95-116 ◽  
Author(s):  
Audouin Dollfus
Keyword(s):  
The Other ◽  
The Moon ◽  
Laboratory Measurements ◽  
Martian Surface ◽  
Dust Deposit ◽  
Asteroidal Belt ◽  
Satellites Of Jupiter ◽  
Celestial Bodies ◽  
Remote Determination

Curves of polarization are available at present for asteroids Vesta, Ceres, Pallas, Iris, Flora, and Icarus. These curves are compared with those of the satellites of Jupiter and Mercury, the Moon, and Mars. Laboratory simulations had already proved that the Moon's surface behaves like a powder of pulverized basalts; the recent confirmation by direct exploration is proving the significance of the method for remote determination of the surface properties of celestial bodies. The simulation of the Martian surface is found on small grained powders oxidized by ferreous limonite or goethite. New laboratory measurements were conducted to prepare the simulation of the asteroidal surfaces. Samples of the lunar surface returned to Earth provide impact-generated regolith and bare rocks superficially pitted and etched by impacts of the types suggested to be found on asteroidal surfaces; they were analyzed polarimetrically.Preliminary interpretations show that Vesta departs significantly from the other asteroids and cannot be covered by frost deposits or by aggregate cosmic dusts; a regolith-type surface generated by impacts or a coating of cohesive grains is indicated.Ceres, Pallas, and Iris are darker, and their polarizations do not suggest a pure regolithic surface, but cohesive grains or aggregates of dust are indicated.Icarus is 108 times smaller in mass; its polarization authorizes a fluffy, loosely aggregated dust deposit; however, a cometary model with stones embedded in ice is perhaps not ruled out on the basis of the present data.The way in which deep-space missions near the asteroidal belt can improve these results is discussed.

III.—Observations on the Balmer Series of Hydrogen

1925 ◽  
Vol 44 ◽  
pp. 14-20
Author(s):  
A. E. M. Geddes
Keyword(s):  
Quantum Theory ◽  
Total Energy ◽  
The Other ◽  
Elliptical Orbit ◽  
Balmer Series ◽  
Quantum Numbers ◽  
Image Position

According to the quantum theory of the production of spectra the lines Hα and Hβ of the Balmer series in the hydrogen spectrum may be produced in six and eight different ways respectively. This general conclusion, however, has to be modified. The mass of an electron in its elliptical orbit is not constant but depends upon its velocity. Consequently, the total energy of an electron in its orbit must be expressed in the formwhere na and nr are the azimuthal and radial quantum numbers and where , and the other symbols have their usual meaning.

scholarly journals GEOREFERENCING ACCURACY ANALYSIS OF A SINGLE WORLDVIEW-3 IMAGE COLLECTED OVER MILAN

2016 ◽  
Vol XLI-B1 ◽  
pp. 429-434 ◽  
Author(s):  
L. Barazzetti ◽  
F. Roncoroni ◽  
R. Brumana ◽  
M. Previtali
Keyword(s):  
Bias Correction ◽  
Rational Functions ◽  
The Other ◽  
Ground Control ◽  
Control Points ◽  
Accuracy Analysis ◽  
Camera Model ◽  
Ground Control Points ◽  
High Resolution Satellite Imagery ◽  
Very High

The use of rational functions has become a standard for very high-resolution satellite imagery (VHRSI). On the other hand, the overall geolocalization accuracy via direct georeferencing from on board navigation components is much worse than image ground sampling distance (predicted &lt; 3.5 m CE90 for WorldView-3, whereas GSD = 0.31 m for panchromatic images at nadir). &lt;br&gt;&lt;br&gt; This paper presents the georeferencing accuracy results obtained from a single WorldView-3 image processed with a bias compensated RPC camera model. Orientation results for an image collected over Milan are illustrated and discussed for both direct and indirect georeferencing strategies as well as different bias correction parameters estimated from a set of ground control points. Results highlight that the use of a correction based on two shift parameters is optimal for the considered dataset.

scholarly journals Research and Development of a Transportable Optical Ground Station in NICT: The Results of the First Performance Test

2021 ◽  
Vol 9 ◽  
Author(s):  
Yoshihiko Saito ◽  
Hideki Takenaka ◽  
Koichi Shiratama ◽  
Yasushi Munemasa ◽  
Alberto Carrasco-Casado ◽  
...  
Keyword(s):  
High Speed ◽  
Performance Test ◽  
The Other ◽  
Atmospheric Conditions ◽  
Free Space Optical ◽  
Ground Station ◽  
Pointing Accuracy ◽  
Set Up ◽  
Site Diversity ◽  
Diversity Technique

In recent years, the necessity of free-space optical (FSO) communications has increased as a method for realizing high-speed communications between satellites and the ground. However, one disadvantage of FSO communications is the significant influence of the atmosphere. Specifically, FSO communications cannot be utilized under certain atmospheric conditions, especially in the presence of clouds. One of the solutions to this problem is the site diversity technique, which makes it possible to select a given ground station with better atmospheric conditions among a number of fixed ground stations. The other solution is to prepare a ground station that can be moved to a place with better atmospheric conditions. We applied the latter method and developed a transportable optical ground station in NICT. We utilize a realistic telescope diameter, which is about 30 cm at the maximum, capable of being set up quickly, and with a pointing accuracy of about 100 µrad. In addition, it is necessary to prepare a fine-pointing optical system that performs tracking with about 1/10 of the pointing accuracy of the telescope. In this paper, we report the results of the first performance test of the transportable optical ground station in NICT.

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