A compressive-sampling Stepped-Frequency Continuous Wave sodar system

Obtaining a high range resolution is an important issue in a detection and ranging system, such as in a radar (Radio Detection and Ranging) or sodar (Sonic Detection and Ranging). A frequency-domain system, such as the SFCW (Stepped-Frequency Continuous-Wave), capable to offer a high range-resolution due to its capability of wide-band scanning, as showed in the SFCW-GPR system. Despite its simplicity, the SFCW system has a drawback in the acquisition time. In order to improve the speed, a recent signal processing technique called compressive sampling (CS) is employed. A series of simulation, experiment, and measurement processes have been done to determine the range resolution produced by the system. From the results, we realize that the reduction of the number of frequency samples does not degrade the range resolution, however it increase the noise/clutter level in the range profile produced by the reconstruction process; less number of samples imply higher noise level in the range profile. Using off-the shelf components, we built the CS-SFCW sodar prototype, with range resolution of about 2 cm.