Assessing Vehicle Exterior Noise Using a Virtual Phased Array (VPA)

Exterior noise testing is one of the main standardized quality controls required for developing the majority of vehicles. The combination of static tests and on-road measurements provides an essential key to undertaking a successful refinement process. Beamforming techniques using phased microphone arrays are one of the most common tools for localizing and quantifying noise sources across the vehicle body. However, the use of such devices can result in a series of well-known disadvantages regarding, for instance, their very high cost or transducer calibration problems. Virtual Phased Arrays (VPAs) are proposed as an alternative solution to prevent these difficulties providing the sound field is time stationary. Several frequency domain beamforming techniques can be adapted to only use the relative phase between a fixed and a moving transducer. Therefore the results traditionally obtained using large arrays can be emulated by applying beamforming algorithms to data acquired from two sensors. Simulations and experimental data presented in this paper introduce a first approach to use virtual phased arrays for assessing complex noise problems, such as vehicle exterior noise radiation.