Investigation of short-range high precision 3D localization via UWB radio

Ultra-wideband (UWB) technology can provide a ranging accuracy of tens of centimeters with fine time resolution. UWB radio occupies a large bandwidth, e.g. at least 500 MHz, which translates to high multipath resolution. Thus, UWB is a suitable technology for accurate positioning through estimating time of flight (TOF) of the transmitted signal. In this paper, we present a highly accurate positioning scheme by estimating the round trip time (RTT) of frequency-converted transponded signal. The proposed scheme avoids complicated beam-forming techniques and clock synchronization between the unknown terminal and the referenced stations. To avoid employing high rate sampling analog-to-digital converters, we propose a novel time estimation method based on sliding correlation and a fractional delay polyphase filter. We use low-rate sampling data with polyphase filter to estimate the RTT, and obtain an equivalent sampling rate as high as tens of gigahertz. The theoretical analysis and numerical experiments demonstrate that the proposed scheme can realize high accuracy positioning.