Innertial navigation systems are systems required in aircrafts, UAVs, drones, etc. In this regard, if the speed for generating and processing information inside an INS is increased, then the functioning of the system, where the INS is integrated, will also improve. Particularly, an INS has accelerometers that usually generate information as frequency variations. In this sense, an adequate frequency approximation method is required. In this work, we study the application of the principle of rational approximations for measuring the frequency generated by an accelerometer. In addition, an evaluation of the parameters that affect the frequency measurement process is offered.