VSpace: Vehicle Spatially-Aware Sensing via Acoustic Doppler Effect

Motivated by safety challenges resulting from distracted pedestrians, we design and implement VSpace, a system that achieves spatially-aware sensing of oncoming vehicles based on the Doppler Effect of vehicle sound. VSpace can figure out the natural velocity, direction, and minimum distance of an oncoming vehicle by acoustic Doppler profiling online. VSpace works in four major steps: (1)Vehicle acoustic signal processing; (2)Vehicle classification; (3)Vehicle sound Doppler profiling and (4)Vehicle spatial status reconstruction. All implementation of VSpace is based on a COTS smartphone with a microphone. We evaluate VSpace with comprehensive experiments of 20 different vehicles in 240 practical cases, in which VSpace achieves an accuracy of 91.67% in vehicle classification and 10.85%, 13.81%, 11.59% relative error for natural velocity, direction, and minimum distance calculation.