Practical experience in noise mapping with a MEMS microphone based distributed noise measurement system

The first round of noise mapping exercises, required by the European Noise Directive, are now complete. A criticism of the mandated software modeling approach expressed by some researchers across Europe, is the absence of a role for measurement in the process, which is often neglected because of its high intrinsic costs. DREAMSys is a MEMS microphone based measurement system that has been developed by an industrial consortium led by NPL, to address this problem. The paper briefly describes the rationale for developing the system, and then focuses on experiences gained in deploying it at a number of test sites where long-term outdoor measurement trials are in progress. Until now, distributed measurement systems employing large numbers of sensors (5-100 or more), have been restricted to specialised applications having large financial resources available to them. DREAMSys has been designed to make wide-scale distributed measurement readily accessible to the general noise measurement practitioner. Initial results are discussed that show (a) the added value of including experimental measurements in the noise mapping process, and (b) the potential of MEMS microphones in measurement applications.