A novel UWB chirp sequence radar signal processing concept for chipless RFID based vehicle localization

Localization of vehicles in industrial environments is a challenging task due to the high demands on the radar system because of harsh environmental conditions and strong multipath propagation. Chipless radio identification (RFID) is well suited for this type of task due to its low-cost production and extreme robustness against environmental influences. Furthermore, RFID transponders based on time domain reflectometry can be interrogated by chirp sequence radar systems. To achieve high data capacities and acceptable tag dimensions, we use an ultra-wideband system. High integration/measurement times that are reasonable yield increased velocity resolution and sufficient signal-to-noise ratios. If a 2D-FFT-based processing step is applied, the high measurement time combined with the high relative bandwidth lead to a smearing in velocity and range dimensions, which significantly diminishes system performance. We first investigate the reasons for this effect, which prevents the TDR RFID transponder from being decoded, and then propose appropriate remedial action. We verify the applicability of the presented UWB chirp sequence processing technique to localize vehicles using chipless RFID by experiments in a laboratory.