High-Accuracy Narrowband Software-Defined Radar Using Successive Multiple-Frequency Continuous-Wave Modulation for Sensing Applications

This paper describes a software-defined radar sensor based on successive multiple-frequency continuous-wave (S-MFCW) modulation. S-MFCW is a radar modulation technique capable of detecting static and moving targets with high accuracy while modulating the transmitted signal over a narrow frequency bandwidth. The proposed software-defined radar is implemented as a highly reconfigurable system made of a field-programmable gate array (FPGA)-based system-on-chip (SoC), a wideband homodyne radio frequency (RF) transceiver, and two antennas. The utilized programmable general-purpose SoC and transceiver front end allow for some of the radar components to be reconfigured by a software program running on the SoC. This radar system adequately follows the software-defined radar paradigm wherein most of the radar operation is configured and controlled using software programs, thus providing the ability to combine multiple radar functions on the same hardware resource. The presented radar sensor is experimentally evaluated in both outdoor and indoor measurement scenarios. The radar operates in the S-band and occupies a narrow virtual bandwidth of 34 MHz when transmitting S-MFCW tones whose frequencies are shifted by two gaps of 4 and 30 MHz, from 3.550 to 3.584 GHz. Experimental results show that the proposed radar system is capable of measuring short-range targets with a range accuracy of less than 21 cm.