Time-of-arrival estimation by UWB radios with low sampling rate and clock drift calibration

• Low-rate stroboscopic sampling is applied to an impulse-radio ultra-wideband (IR-UWB) system for accurate time-of-arrival (TOA) estimation.
• A clock drift calibration method is proposed, as the clock drift is one of the main errors in TOA estimation.
• The clock drift calibration reduces the estimation errors, and stroboscopic sampling achieves the same estimation resolution as Nyquist rate sampling.

In this paper, we propose a time-of-arrival (TOA) estimation scheme using impulse-radio ultra-wideband (IR-UWB). This scheme is featured by a low sampling rate and is robust against clock drift. Low-rate stroboscopic sampling, which can achieve an equivalent sampling rate as high as the Nyquist sampling rate, is adopted to achieve a high resolution TOA estimate by IR-UWB. Since a long preamble is required to collect sufficient data samples, the clock drift is one of the main error sources in TOA estimation with stroboscopic sampling IR-UWB systems. Taking the drift into account, we first obtain a maximum-likelihood (ML) estimate of the drift, and then estimate the TOA using the averaged data samples calibrated for the drift. Simulation results corroborate that the associated drift calibration significantly reduces the TOA estimation errors, and that stroboscopic sampling can achieve the same estimation resolution as Nyquist rate sampling.