Astronomy and Astrophysics – Astronomy
Scientific paper
May 2009
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009iau...261.0901p&link_type=abstract
American Astronomical Society, IAU Symposium #261. Relativity in Fundamental Astronomy: Dynamics, Reference Frames, and Data Ana
Astronomy and Astrophysics
Astronomy
Scientific paper
The number of possible 4D coordinate systems is larger in a relativistic Lorentzian spacetime compared with a Newtonian one. In the 4D Newtonian spacetime, in which the speed of light is infinite, there exist 4 and only 4, causal classes of reference frames. Only one of them is used in the GPS system. However, in the relativistic 4D Lorentzian spacetime, due to the freedom introduced by the finite propagation of light, there exist 199, and only 199, causal classes of reference frames and the Newtonian ones are a small subclass. A causal class is defined by a tangent frame, the dual coframe and the 2D surfaces generated by the vectors of the frame. Only a causal class among the 199 Lorentzian ones, which do not exists in the Newtonian spacetime, is privileged to construct a generic, gravity free (the previous knowledge of the gravitational field is not necessary) and immediate (non retarded) positioning system. This is the causal class of the emission coordinate system. In this causal class, the coframe is non-orthogonal, real and null and the four vectors of the frame are spacelike. Emission coordinates are defined and generated by four emitters broadcasting their proper times. The emission coordinates are covariant (frame independent) and hence valid for any user. Any observer can obtain the values of the emission coordinates of the emitters which provide him his trajectory. If the emitters also broadcast to the users the proper times they are receiving by cross-link autonavigation from the other emitters, the system is called autonomous. In this case, the trajectories of the emitters can be also known by the users.
The authors are partially supported by the Spanish Ministry of Education and Science MEC-FEDER ESP2006-01263 grant.
Pascual-Sánchez Jose F.
San Miguel A.
Vicente F.
No associations
LandOfFree
Relativistic vs Newtonian Frames: Emission Coordinates does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Relativistic vs Newtonian Frames: Emission Coordinates, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Relativistic vs Newtonian Frames: Emission Coordinates will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-811880