A Simple Solution To The Uncertain Delay Problem in USRP Based SDR-Radar Systems

We propose a simple solution to the uncertain delay problem in USRP (Universal Software Radio Peripheral)based SDR (Software-Defined Radio)-radar systems. Instead of time-synchronization as employed in (pseudo-) passive radar configurations, which require two or more synchronized receivers, we use direct reception (antennato-antenna) signal in a single receiver system as a reference to the exact location of the target echoes. After finding the reference position, reordering of the echoes is conducted by circular shift so that the reference moved to the origin. We demonstrate the effectiveness of the proposed method by simulating the problem in Matlab and implementing a 128 length random code radar in a USRP. The random code is constructed from zero padded Barker sequence product. Experiments on measuring multiple echoes of the targets at precise range bins confirm the applicability of the proposed method.