Aug 25, 2026
End-to-end multimodal driving has progressed rapidly by fusing camera and LiDAR streams. Existing pipelines remain fragile under asymmetric sensor degradation, where either an entire modality or only a localized region is corrupted while other regions remain useful. The key difficulty is not simply to add an uncertainty head, but to obtain dense reliability supervision, calibrate this reliability against physical fault severity, and use it before unreliable features bias the planner. We propose Variance-Guided Spatial Attention Fusion (VG-SAF), in which dense heteroscedastic reliability estimates act as interpretable spatial gates. The framework couples three components. First, a physically grounded augmentor simulates representative camera and LiDAR failures and emits a continuous spatial mask, providing dense supervision without additional annotation. Second, modality-specific experts predict per-pixel reliability scales through cross-branch dense distillation in log space, enforcing a monotone severity-to-scale response. Third, calibrated reliability maps drive a hybrid attention mechanism that suppresses unreliable cells with a local spatial gate and arbitrates between modalities through a cross-modal trust softmax. A Laplace uncertainty head emits a systemic waypoint uncertainty scale that signals severe or combined sensor degradation, including severities outside the training ranges. On the CARLA Longest6 benchmark, VG-SAF consistently improves closed-loop robustness over the baselines across camera-only, LiDAR-only, and joint degradation regimes, as measured by driving score, route completion, and infraction score.
Weizhi Tao, Zengwang Jin, Xiao Wang +1
Department of Aeronautical and Aviation Engineering, The Hong Kong Polytechnic University, 999077, Hong Kong, China · School of Robotics, Anhui University, Hefei 230039, China; with the Anhui Provincial Engineering Research Center for Unmanned System and Intelligent Technology, Anhui University, Hefei 230039, China; and also with the Shenzhen Research Institute of Northwestern Polytechnical University, Shenzhen 518057, China · School of Robotics and Institute of Embodied Intelligence, Anhui University, Hefei 230039, China