Detection of Beat Frequency in GPR Signal Using Zoom MUSIC

This research deals with the signal analysis problem faced in a ground penetrating radar (GPR) system. The objects located underground are at close vicinity, as a result the beat frequencies corresponding to the range of these objects are closely spaced. The paper introduces the application of Digital Down Converter (DDC) and Zoom Multiple Signal Classification (ZMUSIC) to detect the beat frequencies of interest. To implement the system, in the first section, the RF receiver is modified which contains the analog IQ mixer to detect the beat frequencies. This mixer is implemented in digital domain using DDC with multistage decimation. The beat frequencies of interest are located in a particular range in the received spectrum and they are closely spaced. In the second section, to detect these beat frequencies Zoom MUSIC algorithm is used and it is divided into two parts, the Zoom unit and the MUSIC algorithm. The Zoom unit is used to zoom into the region of interest in the spectrum while MUSIC is used for the detection of closely spaced beat frequencies. The technique on comparison with other algorithms such as ZFFT and MUSIC showed better ability to distinguish between two closely spaced frequencies.