Demonstrations of the directional noise monitoring system DINOS

Wednesday mornings DINOS is demonstrated around the Schiphol main port.

Fig. 1. Soundtrack of two aircraft passing by a time interval of 45 seconds. The A-weighted strength is expressed re. 20 μP.

The detection and tracking of aircraft will be

demonstrated as shown in Fig.1.

The technique of tracking is based on extended

 Kalman estimation (in real time), using the

acoustic signals from the four microphones.

The model in the estimation is an aircraft flying

with a constant velocity, with the coordinates

based on the finite sound velocity.

Since the origin direction of the noise is known

very accurately noise measurements are

possible.

Also with the same estimation technique the horizontal wind speed vector is determined

The latter with a much longer time constant as for tracking of aircraft.

The non-coherent noise in the microphones signals, for example induced by rain and wind, but

also by the electronics and digitizing is decreased substantially This is shown by wind induced

noise.

All kinds of interesting parameters or figures can be obtained from the acoustic signals, such as

 the energy of the directly received noise as function of time and coordinates, ground reflection,

background noise, rain/wind induced noise, ground traffic, etc..

Fig.2 for example shows aircraft noise spectra in real time.

Fig. 2. Waterfall of A-weighted spectra of noise of the passage of an aircraft in 1/3 octave bands re. 20 μP/√Hz with the directivity augmented

For the exact time and location of the demonstration or tests phone 06-13060880.