Asynchronous Terrestrial Signal of Opportunity-Based Self-Localization With Source Location Uncertainty: Methods and Analysis

The spatiotemporal uncertainties arising from asynchronous signals and limited, inaccurate source location information pose a significant challenge in signal of opportunity (SOP)-based localization. In this article, we consider using a terminal with limited spatiotemporal knowledge to achieve self-localization and source state estimation with terrestrial SOPs (TSOPs) in Global Navigation Satellite System-unavailable scenarios. The formulated TSOP localization problem simultaneously solves the terminal positions across multiple time steps to address the issue of insufficient measurements. To overcome the nonconvexity of the formulated problem, a clock parameter vector elimination-based semidefinite programming (CVE-SDP) approach is proposed. Equivalent Fisher information matrix (EFIM) analysis is adopted for performance bound evaluation. To alleviate the high computational complexity associated with multitime-step localization, an efficient three-step localization method is also proposed based on CVE-SDP and minimum time step selection criteria determined by EFIM analysis. Simulations and a field test are conducted to evaluate the proposed methods.