A restoration procedure for (non-stationary) signals from moving sources

Moving sources, such as trains, cars and airplanes, provide non-stationary sound and vibration signals in situations where the receiver is not moving with the source. For non-stationary signals there are strong limitations on the use of computerized analysis techniques based on Fourier transformation. For instance, it is not possible to compute reliably either power spectral density functions or coherence functions. A procedure has been developed, and is discussed in this paper, that restores non-stationary signals into stationary ones, thus enabling one to apply the analysis techniques mentioned above to moving source data with a reliable outcome.