Re-examine the two principles of special relativity and the Sagnac effect using GPS´ range measurement equation

Successful GPS operations are based on a basic equation: the range measurement equation, |r_r(t_r)-r_s(t_s)|=c(t_r -t_s), in an Earth-centered inertial system. The calculations based this equation show that the correctness of the equation leads to the incorrectness of the two principles of special relativity, the principle of the constancy of the speed of light and the principle of relativity. Moreover, the Sagnac (1913) effect can be fully interpreted by this equation and therefore, the Sagnac effect is a non-relativistic effect. It is indicated that the relativity of simultaneity of special relativity contradicts the basic operational principle of GPS. Furthermore, based on the range measurement equation, it is expected that a practical and crucial experiment that does not require any clock synchronization will give a result contradicting the two principles of special relativity. The crucial experiment can be further simplified by using GPS. We should conduct the crucial experiment, and re-examine and reconstruct special relativity starting from its foundations