Embodiments of the present invention are directed toward a system and method of determining real time chest compression depth of a CPR patient or manikin from acceleration and a reference signal, such as force. In one embodiment, an acceleration signal is filtered and integrated to determine a raw depth signal. A force signal is adjusted to having a similar amplitude, phase, and shape as the raw depth signal. The force signal is filtered. The adjusted force signal is subtracted from the filtered force signal to obtain a compensation signal. The chest compression depth is obtained by adding the raw depth signal to the compensation signal.
