Implementation and performances of a GNSS based system for the determination of the pass-by noise produced by vehicles

This paper describes an innovative pass-by system developed to fulfil the ISO 362-X standards requirements. It is open to the needs of the NVH field because of its design and software modularity. This system is based on a GPS receiver able to track twenty times per second both the vehicle position and its speed. An in-vehicle module acts as an interface for the driver and gathers several kinds of dynamic data. In the meantime a ground station collects all the information about the acoustical parameters of the pass-by test. A bi-directional high transfer rate data connection via Wireless LAN is established between the in-vehicle unit and the ground station, allowing a real time data transfer of the main parameters. At the end of the test, the main acoustical data and the GPS quality parameters are shown to the driver, that can decide whether to accept or reject the measurement session. The main advantages in using this system are: lightweight, less cables and ease of use if compared with the conventional systems.