Coordinate System And Coordinate Transformations Based On Wave Nature Of   Light
  The Classical Coordinate System is geometrical by nature with time being an external variable. Constructing a classical coordinate system employs a point-like signal with infinite speed. In Special Relativity Theory the speed is limited but the signal is a point-like particle (photon). If the oscillatory nature of light is considered, an event in absolute space is to be characterized by three coordinates namely, distance, time and phase. The Galilean transformation equations for space and time coordinates should be complemented by a third equation that accounts for the phase transformation. Wave equation remains invariant under such transformation and kinematical equivalence of inertial reference frames is conserved. Lorentz transforms apply to wave length and wave period of the exchanged light signal in a dynamic set-up. 
M. F. Yagan