News: Testing improved noise measurements around Schiphol

There are 41 noise measuring posts in the area around Schiphol that we use to measure air traffic noise levels to collect data. We have just begun a study involving three of these posts – in Nieuw-Vennep, Spaarndam and Castricum – to see if we can improve the quality of the noise measurements, so that noise can be more accurately linked to a specific flight.

Published on: 8 September 2021

Measuring aircraft noise

The measuring posts are basically masts of between 6 and 10 metres-high with a microphone on them. The microphones, that can also often be found on the roofs of buildings, constantly measure noise in the area. As soon as noise exceeds a threshold of around 60 decibels, a sound recording of between 10 and 120 seconds is made. This allows us to measure how the noise develops. The recording is then analysed and, together with radar data and a noise prognosis, we can link a particular noise measurement to a flight.

New analysis method

Currently, the noise made by around 85 percent of the flights within one kilometer of the post is measured. And that figure is less for flights within two kilometers of the post. Sometimes it can be that a noise measurement is mistakenly linked to a flight. To improve this in the future, we are testing a new method of analysing noise. We are investigating whether the threshold can be adjusted afterwards, so that we don’t miss any flights and so that we can link noise measurements to flights later on. We hope to see the biggest improvements at measuring posts where multiple flights follow each other in quick succession (where it is hard to link the measurements to a specific flight), and at the posts located further away from the runways (where we migt need to adjust the threshold).

First results are promising

The tests are being carried out using measuring posts 15 in Nieuw-Vennep, 19 in Spaarndam and 32 in Castricum. The first results of a third-party test show that around 95 percent of the flights were assessed for noise. The aim of this study is to find out whether this new method of analysis works well and does not produce too many invalid measurements.

Want to know more about noise measurement around Schiphol? Go to NOMOS online.