Knowing the position of bones during movement can help in the improvement of healing therapies. The exact localization of the bone is determined measuring the time-of-flight of the echo of an ultrasonic pulse. The ultrasonic echo may be corrupted by noise and multipath reflections. The ultrasonic sensor is calibrated, experimental measurements are taken and analyzed with five different algorithms. The best accuracy and repeatability is achieved calculating the cumulative kurtosis of the incoming signal.