Multi-frequency antennas to depict the multi-layer foundation of a building

Here I show that the signal-noise ratio of GPR data acquired to investigate multi-layered foundation can be increased by applying a time spectral whitening (TVSW) inverse filter. I found that the TVSW function produces a balancing of the amplitude of frequencies in the range of useful frequency greater than the peak frequency of signal. The filter is effective for broad-band data of large dynamic range like GPR and induces an increase of vertical resolution and enhances the energy from deep scattered objects because it reduces the low wow noise and the amplitude of wide angle scattered energy. Spectral whitening was tested on multi-frequency data collected with 80-200-600-900-2000MHZ antennas to investigate a 1960´s multi-layered foundation consisting of tiling, sandy and gravel screed layers and loose stone foundation.