Explanation of some of the special features of the noise modelling process using ANCON
Where feasible, we analyse local airport radar data to ensure the highest degree of modelling accuracy. Extensive in-house radar analysis tools are used to generate mean flight tracks and the associated lateral dispersions for each route, and average flight profiles of height, speed and thrust for different aircraft types.
The diagram below shows a typical representation of a departure route at Heathrow using mean and dispersed tracks, together with the underlying radar data.
Typical departure mean tracks © Crown copyright
A typical representation of arrivals at Heathrow using multiple ‘spur’ tracks is shown below:
Typical arrival mean tracks © Crown copyright
It is important to determine flight profiles for the noise dominant types at an airport using local radar data, since they may differ significantly from the ‘default’ profiles supplied in some noise models. For example, the following diagram shows the difference between the average departure height profile for the Boeing 767 as measured at the London airports, and a 'default' profile contained within another noise model.
Comparison between ANCON and another noise model's default profile for Boeing 767
ANCON’s noise database is checked and updated on an annual basis by taking several hundreds of thousands of noise measurements around Heathrow, Gatwick and Stansted airports each year. The noise database contains data for specific airframe/engine combinations in the form of 'noise-power-distance' (NPD) curves, thus it is applicable to any airport. In particular, the database contains extensive noise information for the majority of aircraft types that operate from UK airports, unlike other noise models.
ERCD is able to include the effects of terrain in the noise modelling process for any UK airport. Ordnance Survey’s ‘Meridian 2’ terrain data are used to make corrections for the distance between the aircraft noise source and ground receiver position. Locations that are higher than the runway level will be closer to the noise source and thus experience higher noise levels, and vice versa.
Terrain can often have a significant effect on the shape and size of contours, especially where an airport is located in close proximity to hills or valleys.
The diagram below illustrates the terrain surrounding an airport runway, colour coded by ground height (areas of high ground are shown in green).
We can estimate the areas, populations and number of households enclosed within each contour level using our population database, which is based on the latest UK Census (2001) and updated annually in the light of new data.
The population and households data are referenced to individual postcodes (shown as the square dots on the diagram below).
Using our 'Points of Interest' database, we are also able to determine the numbers of noise sensitive buildings (e.g. schools and hospitals) within a particular noise contour, as well as providing detailed information such as the name and address of each building.