A Joint Localization and Clock Bias Estimation Technique Using Time-of-Arrival at Multiple Antenna Receivers
This work addresses the problem of accurate localization in the presence of clock biases for asynchronous receivers, which is relevant for applications like wireless sensor networks and radar.
The paper proposes a technique for jointly estimating the position of a moving radio emitter and the clock biases of two asynchronous receivers using time-of-arrival measurements from multiple antennas. Simulations show the method achieves mean-squared error close to the Cramer-Rao lower bound and outperforms existing approaches.
In this work, a system scheme is proposed for tracking a radio emitting target moving in two-dimensional space. The localization is based on the use of biased time-of-arrival (TOA) measurements obtained at two asynchronous receivers, each equipped with two closely spaced antennas. By exploiting the multi-antenna configuration and using all the TOA measurements up to current time step, the relative clock bias at each receiver and the target position are jointly estimated by solving a nonlinear least-squares (NLS) problem. To this end, a novel time recursive algorithm is proposed which fully takes advantage of the problem structure to achieve computational efficiency while using orthogonal transformations to ensure numerical reliability. Simulations show that the mean-squared error (MSE) of the proposed method is much smaller than that of existing methods with the same antenna scheme, and approaches the Cramer-Rao lower bound (CRLB) closely.