A Methodological Framework for Effective GNSS RFI Localization Using LEO SDR Platforms

Global Navigation Satellite Systems (GNSS) are vulnerable to radio-frequency interference (RFI). Low Earth Orbit (LEO) satellites equipped with Software-Defined Radio (SDR) payloads offer a promising solution for wide-area RFI monitoring and localization. This paper proposes a methodological framework that integrates link budget validation, jammer impact assessment via carrier-to-noise density ratio degradation, and theoretical localization performance based on time-difference-of-arrival/frequency-difference-of-arrival (TDOA/FDOA) measurements. The framework introduces novel design metrics, namely the coverage and service areas, to jointly account for detection sensitivity and localization accuracy, and defines localization efficiency as a unifying benchmark. A case study demonstrates how realistic jammer transmit power, antenna patterns, and constellation geometry influence detectability and achievable accuracy. Results show localization errors on the order of 4-12 km for representative LEO constellations. The proposed framework provides a systematic benchmark for the design and evaluation of space-based GNSS RFI monitoring systems.