Relativity in the Global Positioning System

Ashby, Neil

doi:10.1142/9789812700988_0010

Cited by 81 publications

(127 citation statements)

References 5 publications

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“…In this context, we note that as a result of studies on global positioning system (GPS) electromagnetic signal data, recognized world leading GPS expert Neil Ashby recently noted in Physics Today, " .. the principle of the constancy of c cannot be applied in a rotating reference frame .." [8].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Anomalous Brillet and Hall Experimental Result

Klauber

2004

Foundations of Physics Letters

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The persistent, second order, anomalous signal found in the Brillet and Hall experiment is derived by applying 4D differential geometry in the rotating earth frame. By incorporating the off diagonal time-space components of the rotating frame metric directly into the analysis, rather than arbitrarily transforming them away, one finds a signal dependence on the surface speed of the earth due to rotation about its axis. This leads to a Brillet-Hall signal prediction in remarkably close agreement with experiment. No signal is predicted from the speed of the earth in solar or galactic orbit, as the associated metric for gravitational orbit has no off diagonal component. To corroborate this result, a repetition by other experimentalists of the Brillet-Hall experiment, in which the test apparatus turns with respect to the earth surface, is urged.

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Section: Introductionmentioning

confidence: 99%

Analysis of the Anomalous Brillet and Hall Experimental Result

Klauber

2004

Foundations of Physics Letters

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“…Since the satellite and receiver positions are defined in the ECEF frame, the Sagnac effect associated with the rotation of earth during the propagation time t pi is normally accounted for (Ashby, 2003). Here we shall only discuss the Sagnac effect, associated with the light speed anisotropy in the ECI frame, induced by the absolute motion of earth during the signal propagation time from satellite to the receiver.…”

Section: Effect Of Absolute Motion On Gps Position Determinationmentioning

confidence: 99%

Detection of Absolute Motion through Measurement of Synchronization Offsets

Sandhu¹

2012

APR

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An absolute reference frame may be defined as the one which is stationary with respect to the center of mass of the Universe and in which speed of propagation of light is an isotropic constant. Any motion with respect to this frame may be referred as absolute motion. In this paper we examine the Sagnac effect of absolute motion in the context of clock synchronization through GPS satellites in common view mode. The e-synchronization of two clocks A and B amounts to introduction of time offsets such that the time taken by a light pulse to propagate between A and B will be measured to be the same in both directions. Synchronization of two clocks through a GPS satellite in common view mode is effectively equivalent to e-synchronization of these clocks and introduces an absolute synchronization mismatch proportional to the absolute velocity and length of the baseline. Measurement of this synchronization offset between the GPS synchronized clocks at the ends of a long baseline will enable the practical detection of absolute motion of earth. Here we propose a simple experiment for detection of absolute motion through measurement of absolute synchronization offsets between two timing laboratories maintaining UTC time.

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“…We are amazed at the sheer quantity of physics involved in the operation of a GPS, 56,57 which allows an instructor the freedom to handpick items for discussion. At minimum, the point is made that to solve the problem of navigation, the Earth had to be surrounded with approximately 30 satellites, all containing atomic clocks.…”

Section: E Modern Navigation: the Global Positioning Systemmentioning

confidence: 99%

The longitude problem from the 1700s to today: An international and general education physics course

Bensky

2009

American Journal of Physics

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For instructors wishing to use physics as part of an international or general education course, the framework for a course based on the "longitude problem" from the 1700s is described. The longitude problem is teeming with basic principles of physics and astronomy, which makes it ideal for a nonscience-major-based college-level course. This paper summarizes the longitude problem in the context of conceptual physics and astronomy and outlines an appropriate curriculum. Specifics on teaching such a course in London, as part of an international studies program, are discussed.

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Relativity in the Global Positioning System

Cited by 81 publications

References 5 publications

Analysis of the Anomalous Brillet and Hall Experimental Result

Analysis of the Anomalous Brillet and Hall Experimental Result

Detection of Absolute Motion through Measurement of Synchronization Offsets

The longitude problem from the 1700s to today: An international and general education physics course

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