Magnetic Anomalies as a Reference for Ground-speed and Map-matching Navigation

1982 ◽  
Vol 35 (2) ◽  
pp. 242-254 ◽  
Author(s):  
Carl Tyrén
Keyword(s):  
Magnetic Field ◽  
Navigation Systems ◽  
Earth’S Magnetic Field ◽  
Electrical Field ◽  
Electrical Fields ◽  
Ground Speed ◽  
The Earth ◽  
Earth's Magnetic Field ◽  
Potential Basis ◽  
The Magnetic Field

The Earth's magnetic field has long provided us with a directional reference of almost worldwide usable coverage. This paper examines the use of the magnetic field for ground referenced motion and position measurementsWhere E is the vector representation of an electrical field, v vehicle velocity and B a magnetic field, the electromagnetic law of induction, E = v × B, indicates one possibility for measuring ground speed; the magnetic and electrical fields experienced by vehicle mounted sensors being used to solve the equation for v. This method however only gives the component of v perpendicular to the magnetic field. There are also certain difficulties associated with the measurement of B, which should be only the magnetic field of the Earth at the location of the vehicle, and E, which should be only the electrical field resulting from vehicle motion relative to the magnetic field of the Earth. The main problem appears to be the inseparability of motion dependent and non dependent electrical fields, a problem analogous to that of gravitation-acceleration inseparability for inertial navigation systems. The relative magnitudes of the vehicle-motiondependent E-field, of the order of 10−5 (volt/metre)/(metre/second), and the ever-present and very variable non-motion-dependent E-field between a highly conductive atmospheric layer at an altitude of about 50 km and the surface of the Earth, of some 102 volt/metre, are particularly unfavourable. Another potential basis for a ground-speed measurement system is the heterogeneous character of the intensity of the Earth's magnetic field.

7. The Earth’s magnetic field

2018 ◽  
pp. 106-126
Author(s):  
William Lowrie
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Field ◽  
Plate Tectonics ◽  
Magnetic Anomalies ◽  
Earth’S Magnetic Field ◽  
The Earth ◽  
Earth's Magnetic Field ◽  
Reversed Polarity ◽  
Harmful Radiation ◽  
The Magnetic Field

The Earth is surrounded by a magnetic field, which originates inside its molten core, and which for centuries has helped travellers to navigate safely across uncharted regions. The magnetic field protects life on the Earth by acting as a shield against harmful radiation from space, especially from the Sun. ‘The Earth’s magnetic field’ explains that the magnetic field at the Earth’s surface is dominantly that of an inclined dipole. The Sun’s deforming effect on the magnetic field outside the Earth is described, as are the magnetic fields of other planets. The magnetism of rocks forms the basis of palaeomagnetism, which explains how plate tectonics displaced the continents and produced oceanic magnetic anomalies whenever the geomagnetic field reversed polarity.

The westward drift of the Earth's magnetic field

1950 ◽  
Vol 243 (859) ◽  
pp. 67-92 ◽  
Keyword(s):  
Magnetic Field ◽  
Secular Variation ◽  
Outer Part ◽  
Earth’S Magnetic Field ◽  
Dynamo Theory ◽  
The Core ◽  
The Earth ◽  
Earth's Magnetic Field ◽  
Harmonic Analyses ◽  
Westward Drift

The westward drift of the non-dipole part of the earth’s magnetic field and of its secular variation is investigated for the period 1907-45 and the uncertainty of the results discussed. It is found that a real drift exists having an angular velocity which is independent of latitude. For the non-dipole field the rate of drift is 0.18 ± 0-015°/year, that for the secular variation is 0.32 ±0-067°/year. The results are confirmed by a study of harmonic analyses made between 1829 and 1945. The drift is explained as a consequence of the dynamo theory of the origin of the earth’s field. This theory required the outer part of the core to rotate less rapidly than the inner part. As a result of electromagnetic forces the solid mantle of the earth is coupled to the core as a whole, and the outer part of the core therefore travels westward relative to the mantle, carrying the minor features of the field with it.

Partial Castastrophism and Pick & Choose Empiricism: The Science of “Creationist” Geology

1984 ◽  
Vol 1 ◽  
pp. 50-65
Author(s):  
William J. Frazier
Keyword(s):  
Magnetic Field ◽  
Sedimentary Rocks ◽  
Decay Rates ◽  
Igneous Rocks ◽  
Earth’S Magnetic Field ◽  
Organic Evolution ◽  
The Earth ◽  
Scientific Principles ◽  
Earth's Magnetic Field ◽  
Repeated Use

“Scientific creationists” have created their own version of geology in order to defend their axiomatic insistance on a young Earth. To “prove” the Earth's youth, they cite (among other things) measured decay-rates of Earth's magnetic field and concentrations of elements in seawater. They also state that all plutons are quick frozen, that plutonic igneous rocks bear no relation to modern volcanism, and that all sedimentary rocks must be interpreted in terms of a “global hydrologic singularity,” i.e. Noah's Flood.Having explicitly denied uniformitarianism and embraced catastrophism, “Creationists” renege by using uniformitarian reasoning over and again. They practice “pick & choose” empiricism by citing only those data which seem to support their case. “Creationists” even choose when and if to apply scientific principles, e.g. their use of thermodynamics to “disprove” organic evolution while ignoring thermodynamics' implications for magma cooling and metamorphism.The methods of “Creationism” are clearly intended not to increase knowledge of the Earth but to delude the scientifically unsophisticated. Thus, “Creationism” can hardly be considered a science. Further, its repeated use of fallacious thinking brands “Creationism” as hopelessly illogical and its disingenuous statements and tactics disqualify it from even the ranks of nonempirical epistemological systems.

scholarly journals Magnetic maps in animal navigation

2022 ◽  
Author(s):  
Kenneth J. Lohmann ◽  
Kayla M. Goforth ◽  
Alayna G. Mackiewicz ◽  
Dana S. Lim ◽  
Catherine M. F. Lohmann
Keyword(s):  
Magnetic Field ◽  
Positional Information ◽  
Natal Philopatry ◽  
Earth’S Magnetic Field ◽  
Long Distance ◽  
Natal Homing ◽  
Potential Source ◽  
Animal Navigation ◽  
Earth's Magnetic Field ◽  
The Magnetic Field

AbstractIn addition to providing animals with a source of directional or ‘compass’ information, Earth’s magnetic field also provides a potential source of positional or ‘map’ information that animals might exploit to assess location. In less than a generation, the idea that animals use Earth’s magnetic field as a kind of map has gone from a contentious hypothesis to a well-established tenet of animal navigation. Diverse animals ranging from lobsters to birds are now known to use magnetic positional information for a variety of purposes, including staying on track along migratory pathways, adjusting food intake at appropriate points in a migration, remaining within a suitable oceanic region, and navigating toward specific goals. Recent findings also indicate that sea turtles, salmon, and at least some birds imprint on the magnetic field of their natal area when young and use this information to facilitate return as adults, a process that may underlie long-distance natal homing (a.k.a. natal philopatry) in many species. Despite recent progress, much remains to be learned about the organization of magnetic maps, how they develop, and how animals use them in navigation.

A Study of the Magnetic Field of the Moon

1962 ◽  
Vol 14 ◽  
pp. 45-52 ◽  
Author(s):  
S. S. Dolginov ◽  
E. G. Eroshenko ◽  
L. I. Zhuzgov ◽  
N. V. Pushkov
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
The Moon ◽  
Earth’S Magnetic Field ◽  
Earth's Magnetic Field ◽  
The Magnetic Field

The question as to whether the planets and their satellites possess magnetic fields unavoidably arose in connection with the question as to the origin of the Earth's mágnetic field and the nature of a number of geophysical effects.

On the possibility of an intra-Earth source of Sq-variations of the Earth's magnetic field

2021 ◽  
Author(s):  
Beibit Zhumabayev ◽  
Ivan Vassilyev
Keyword(s):  
Magnetic Field ◽  
Coordinate System ◽  
Local Coordinate System ◽  
Spherical Body ◽  
Time Of Day ◽  
Magnetic Observatory ◽  
Earth’S Magnetic Field ◽  
The Earth ◽  
Earth's Magnetic Field ◽  
Variation Vector

<p>Analysis of the direction of motion of the vector of Sq-variations of the Earth's magnetic field, depending on the time of day and season of the year, shows that the observed Sq-variation is similar to the magnetic field created by a negatively charged spherical body moving in space. Transformations of the Sq-variation vector from the local coordinate system of the magnetic observatory to the ecliptic coordinate system are performed. A possible connection between the origin of the Sq-variation and the electric dipole moment of quartz molecules oriented towards the center of the Earth during the crystallization of the mineral and causing the electric and dipole magnetic fields of the Earth is considered. A scheme for conducting an experiment that allows us to separate the effects of extraterrestrial and extraterrestrial sources of Sq-variations is proposed.</p>

Study of the Magnetic Fields of Residential Buildings and their Impact on Human Health

2021 ◽  
Vol 23 (4) ◽  
pp. 370-382
Author(s):  
Radka Kostadinova ◽  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Residential Buildings ◽  
Health Condition ◽  
Residential Areas ◽  
Earth’S Magnetic Field ◽  
The People ◽  
Specific Device ◽  
Earth's Magnetic Field ◽  
The Magnetic Field

With the prosperity of civilization people are more often put to the vibrations of the Earth’s magnetic field, which they are affecting by themselves in various ways. Settlements and residential areas, distant and electrical conductors, with its constantly changing electromagnetic field create strong deformations and weaken the Earth’s magnetic field. Is it possible that the reduction of the magnetic fields, in such buildings, to lead to illness and discomfort of the people living there. Is it possible that chronic discomfort and illness of the humans who inhabit those buildings don’t suffer from conditions, we usually connect with junk food, polluted air and the our stressful lifestyle, but are actually a result of the greatly reduced and changing magnetic field in the populated areas. With the research project developed by Tereza Stefanova with the help of students from the school, we tried to answer these questions. The purpose of our research is to: 1. Measure the magnetic field in buildings in our city, which differ by their construction and height and also to measure outside the city. 2. Determine if the change of the magnetic field and possible magnetic anomalies affect our health condition. The tasks we had to do to achieve our goal is to do take the measurements with a specific device.

scholarly journals An experiment on the origin of the earth's magnetic field

1923 ◽  
Vol 104 (727) ◽  
pp. 451-455 ◽  
Keyword(s):  
Magnetic Field ◽  
Slight Modification ◽  
Residual Effects ◽  
Earth’S Magnetic Field ◽  
Gravitational Action ◽  
Earth's Magnetic Field ◽  
Intimate Mixture ◽  
The Many ◽  
The Magnetic Field ◽  
Accepted Form

Of the many suggestions which have been made as to the origin of the earth’s magnetic field, perhaps the most promising is that it may be due to a slight modification of the laws of electrodynamics from the commonly accepted form. Electrically neutral matter is believed to consist of an intimate mixture of enormous amounts of positive and negative electricities, the electric and magnetic effects of which are usually supposed to balance each other. If the balance were not quite exact then small residual effects would be expected, among which gravitation and the earth’s magnetic field might be included. On such an hypothesis we might expect moving matter to produce a magnetic field similar to the field due to moving electricity, and we should expect some relation between the magnetic field due to moving matter and its gravitational action.

scholarly journals GEODYNAMICS

GEODYNAMICS ◽  
2011 ◽  
Vol 2(11)2011 (2(11)) ◽  
pp. 284-286
Author(s):  
V. Semenov ◽  
◽  
J. Vozar ◽  
Yu. P. Sumaruk ◽  
B. Ladanivskyy ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Low Frequency ◽  
Outer Ring ◽  
Current Position ◽  
Earth’S Magnetic Field ◽  
The Earth ◽  
Ring Currents ◽  
Geomagnetic Pole ◽  
Earth's Magnetic Field ◽  
Magnetic Poles

It is known that magnetic poles of the Earth is accelerated and is now being ≈ 50 km/year (Olsen & Mandea, 2007) while the geomagnetic pole (the dipole part), which is computed (fictitious) value, has much less velocity. It is believed that the magnetospheric outer ring currents are held by the dipole part of the Earth’s magnetic field. The low frequency magnetic variations of that source allow determine the current position of the source axis and its corresponding pole which as shown experimentally precesses around the geomagnetic pole.

Thermoelectric model of the Earth's magnetic field

2021 ◽  
pp. 39-52
Author(s):  
A. N. Dmitriev ◽  
Yu. V. Pakharukov
Keyword(s):  
Magnetic Field ◽  
Inner Core ◽  
Inversion Process ◽  
Earth’S Magnetic Field ◽  
The Earth ◽  
Dipole Magnetic Field ◽  
Earth's Magnetic Field ◽  
Direction Of Movement ◽  
The Moment ◽  
Thermoelectric Model

A variant of the thermoelectric model of the Earth's dipole magnetic field is considered. It is based on geothermoelectric currents present in the planet's core. The currents cyclically change their direction, which leads over time either to warming on the Earth, if their movement is directed towards the Earth's crust, or to cooling, when moving towards the inner core. With each change in the direction of movement of the thermal currents, the poles of the Earth's magnetic field are inverted simultaneously. The inversion process is instantaneous (on the scale of planetary time) and is not the result of a gradual reversal on the 180° Earth's magnetic axis. At the moment of inversions of thermal currents in the core, the total geomagnetic field decreases to the level of 4.6∙10-6 T, which is constantly supported by thermal currents of semi-conducting rocks of the lower mantle. The considered version of the thermoelectric model of the Earth's magnetic field may be promising for studying the magnetic fields of planets in the Solar system.

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