SDR-based Radar for Human Detection

Software-defined radios (SDRs) have been applied to several applications, taking advantage of their inherent versatility. It is reported a low-cost radar intended to detect human activity, at the frequency of 4.1 GHz, with an SDR on the receiving branch and a programmable RF synthesizer operating as a continuous-wave transmitter. Amplitude variations on the received signal indicate human activity, its operation is tested in indoor and outdoor scenarios. The interface to the SDR is performed using the open-source tool GNU Radio. It was possible to detect human movement at a maximum distance of 9 meters, in an open area. The system is versatile in terms of power and frequency, totally controlled by software in a transparent and straightforward way.