Ultra wideband digital receiver implemented on FPGA for mobile robot indoor self-localization

Abstract

In impulse-based UWB systems, positional accuracy is inversely proportional to the signal bandwidth. In this work, a number of anchor nodes are located at fixed positions in an indoor environment transmitting synchronized 2.5ns pulses with Differential Binary Phase Shift Keying (DBPSK) modulation. An UWB receiver mounted on a mobile robot utilizes Time Difference of Arrival (TDOA) between pairs of synchronized transmitting anchor nodes for localization. Self-localization implies that position estimation algorithms run locally on the mobile robot. A prototype non-coherent UWB receiver using off-the-shelf components is implemented where signal acquisition runs on a Field Programmable Gate Array (FPGA). Measurement results indicate sub-20cm positional accuracy with Line Of Sight (LOS) and Non-Line of Sight (NLOS) conditions relative to fixed anchor nodes in a typical indoor environment.