Range-Gated Micro-Doppler Dynamic Structures From Standard 802.15.4z UWB Radar for Non-Contact Bearing Fault Perception at Low Rotational Speed

Low-speed rotating machinery presents a structural contradiction for vibration sensing: contact accelerometers degrade sharply at 3–10 Hz because acceleration scales with the square of frequency, while laser vision, and millimeter-wave CW radar alternatives collapse to single-point or single-peak readouts, losing the spatial-spectral reorganization that carries early fault information. We propose and validate a range-resolved vibration sensing modality built on the native channel impulse response (CIR of commodity IEEE 802.15.4z/4ab impulse ultra-wideband (UWB) transceivers: target range gates are selected by multi-metric scoring, slow-time micro-Doppler dynamic structures are constructed, and a physically interpretable structural feature group (spectral centroid, spread, entropy, far-gate dynamic ratio, gate-centroid migration, cross-channel correlation) is extracted. The advantage lies not in carrier or bandwidth, but in using range gates as spatial constraints and dynamic structures as the observation, making spectral reorganization and energy migration observable under low-speed weak faults. On a bearing rig with a 1T2R radar (HRP channel 9, 7.9872 GHz, 1.3 GHz bandwidth, 100 Hz frame), four conditions, five distances, and three speeds (101 recordings, about 437k CIR frames), rotational harmonics resolve to the 5th order at all speeds; fault-induced structural shifts are direction-consistent at 84–94% over 31 distance–speed pairs; leave-one-file-out detection reaches 88.4–90.9%; and key-feature repeatability CV is 0.05–0.13. Standard UWB radar thus stands as a non-contact sensing channel precisely where vibration sensing is weakest. This work has been submitted to IEEE Sensors Journal for possible publication. Copyright may be transferred upon acceptance, after which the published version will be available on IEEE Xplore.