RONDA open frame CPX trailer - Certification in accordance with ISO/CD 11819-2

摘要

RONDA (ROad Noise Data Acquirer) is a CPX trailer conforming to ISO Standard ISO/CD 11819-2 intended for measuring road surface noise. The trailer is of the open frame construction without an enclosure. The results of certification testing in accordance with the ISO Standard is described in particular a) Annex A.2 sound reflections against an enclosure (if any) and other objects close to the microphones and b) Section 8.1 the effect of wind on the microphones. These issues are particular relevant to open frame trailers which by their inherent design are potentially susceptible to wind noise. Whilst not considered in the ISO Standard, the contribution of noise from the tyre located on the far side of the trailer is also evaluated and an error correction term is derived. This correction is relevant to both enclosed and open framed trailers.