TDOA-Based Spoofing Source Localization Using Multi-Constellation Unsynchronized Receivers

Jade Babcock-Chi, Sherman Lo, Yu-Hsuan Chen, Juan Blanch, Todd Walter

Abstract:	Airports, transportation systems, power grids, and other critical infrastructure that depend on GNSS positioning and timing services are particularly vulnerable to the growing threat of spoofing. Rapid localization of spoofed signals is essential to enable timely mitigation and minimize operational disruption. This work investigates the localization of meaconer and spoofer transmitters using a network of stationary, low-cost, unsynchronized, multi-constellation commercial off-the-shelf (COTS) receivers. The approach estimates transmitter position in two dimensions via time-difference-of-arrival (TDOA) and nonlinear least squares (NLLS) using pseudorange double differences, applied across multiple GNSS constellations and frequencies. Results demonstrate that when the transmitter is located outside the receiver network, localization reduces to a direction-of-arrival estimate with less than 2 ? average angular error from the network centroid. Conversely, when the transmitter is located inside the network, latitude–longitude solutions achieve an average positional error of less than 40 m. These findings highlight the feasibility of a flexible, low-cost approach to spoofer localization.
Published in:	Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025) September 8 - 12, 2025 Hilton Baltimore Inner Harbor Baltimore, Maryland
Pages:	778 - 796
Cite this article:	Babcock-Chi, Jade, Lo, Sherman, Chen, Yu-Hsuan, Blanch, Juan, Walter, Todd, "TDOA-Based Spoofing Source Localization Using Multi-Constellation Unsynchronized Receivers," Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025), Baltimore, Maryland, September 2025, pp. 778-796. https://doi.org/10.33012/2025.20369
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