Temperature-Adaptive Multi-Sensor Fusion for High-Speed Guided Missiles Under Aerodynamic Heating

초록

High-speed guided missiles flying at Mach 2.5 or above experience rapid infrared dome temperature rise due to aerodynamic heating, which degrades MWIR (Mid-Wave Infrared) seeker measurement accuracy and may cause tracking errors during terminal guidance. Conventional fixed-parameter sensor fusion methods do not sufficiently compensate for this thermal degradation, leading to underestimated sensor noise levels and excessive weighting of degraded MWIR measurements. This study proposes a dome temperature-based adaptive multi-sensor fusion technique to address this issue. The method adopts a three-mode operational framework based on physical temperature thresholds. In low and medium temperature regimes, preset noise models are applied, while an Extended Kalman Filter (EKF) is activated only in the high-temperature regime to estimate the degradation parameter $\kappa$ in real time. This selective activation limits unnecessary computation and avoids estimation instability under insufficient observability. The estimated parameter is used to reconstruct the MWIR noise variance through the degradation model and to update fusion weights among MWIR, EO, and RF sensors. A conservative weight adjustment proportional to the estimation error covariance is introduced to maintain stable fusion performance during the initial estimation phase. To validate the proposed method, 24,000 Monte Carlo simulations were conducted under four flight conditions (Mach 1.5-3.0) and four threat scenarios. Under Mach 3.0 compound threat conditions, the proposed method achieved up to 6.1% reduction in maximum tracking error compared with a fixed-parameter implementation. In lower-speed regimes where thermal degradation remains mild, performance differences are not statistically significant. The resulting Circular Error Probable (CEP) was 1.32 m, corresponding to 98.5% of an ideal oracle baseline. The algorithm is implemented entirely in software and requires no additional hardware modification, allowing integration into existing seeker processors under practical SWaP-C constraints.

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