High resolution approach for phase based TOF ranging using compressive sampling

Phase measurement based time-of-flight ranging techniques are a valid approach for radio-frequency distance measurements using a small relative bandwidth. Step-frequency radar enhances this approach for application on multiple frequencies. In case of presence of narrowband interference, distance calculations are possibly affected depending on the number of frequencies measured and the type of the antennae used. The Inverse Fast Fourier Transform (IFFT) tends to be robust against interferences compared to calculation of a weighted mean. Resolution of IFFT and therefore accuracy of the ranging result depends on the number of measurement taps available. In this paper, the Compressive Sampling (CS) approach is investigated to increase the resolution of IFFT. It is shown that the CS approach is applicable for SFR in such scenario. Field tests have been performed for verification using a commercial ranging system from ZigPos company with different prototype antennae to minimize multipath influence in indoor environment.