Abstract
Three inertial measurement processing techniques were developed to measure the longitudinal level of tracks using devices mounted on commercial shinkansen trains. Two techniques employ digital processing and are labeled as the "Frequency variable difference filter" and the "Speed variable moving summation". The other technique employs analogue processing using a frequency variable low-pass filter. Test results confirmed that all methods are able to directly calculate a 10 m versine longitudinal level with high precision without any waveform distortion. An experimental prototype of a digital inertial device applying the "Frequency variable difference filter" with small hardware load was made, and a test was conducted to confirm its performance. As a result, the output of the prototype achieved good correlation with data from the existing track geometry car.
