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Reply to a comment by S. Svitlov on "Relativistic Theory of the Falling Cube Gravimeter"



Neil Ashby


In the subject paper [1] of the comment, light propagation through an absolute gravimeter was analyzed, including the propagation delay through the falling retroreflector and through the vacuum. The resulting expression for the interference signal applies without any subsequent "speed-of-light" correction. Other corrections appeared for the three fitting parameters $Z_0,\ V_0$ and $g$, which are the initial position and velocity, and the acceleration of gravity at the reference point. The comment assumes the value of $Z_0$ is known apriori; this case was not addressed in [1]. Also, the comment misunderstands statements made in [1] regarding the derivation of the relativistic/nonrelativistic parts of the corrections (Eq. (47) of [1]), and mistakenly claims they apply to the undifferenced interference signal. In this reply we show why, because of inapplicable assumptions, approximations and misunderstandings, the comment does not apply to the results of [1].


acceleration of gravity, geodesy, relativity, retroreflectors


Ashby, N. (2017), Reply to a comment by S. Svitlov on "Relativistic Theory of the Falling Cube Gravimeter", Metrologia, [online], (Accessed June 18, 2024)


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Created December 12, 2017, Updated February 21, 2019