Like for the ground force spectra, there is a clear difference between the ground vibration spectrum generated by the APC wheeled vehicle and the one created by the tracked vehicle (MBT). For the Transportpanzer APC, a single major peak is present within the range 0-200 Hz-at a frequency associated with the tyre tread periodicity. The overall level of generated vibrations in this case is much lower than for the tank.
A comparison of above-mentioned theoretical result with the experimental normalized power speatrum of ground vibration generated by the Leopard-1 MBT at 11.8 m distance from the sensor 4 is given in Fig8. For convenience of comparison, the theoretical spectrum has been plotted for a square of ground vibration velocity, like the original experimental spectrum that has been reproduved with kind permission from Fig8 of the paper. Note that measurements in 4 have been processed using Hann window and determination of mean square spectral amplitudes, whereas in the present work no window and no mean square amplitudes have been simulated. Therefore, strictly speaking, one should not expect good agreement between the absolute levels of calculated and measured spectral peaks.