Accuracy of Data in the Noise and Track Keeping System at the London Airports

This report describes a study that was undertaken to assess the accuracy of the flight path information provided by ANOMS 8 – the Noise and Track Keeping (NTK) system installed at the London airports. Aircraft positional data recorded using Mode S/ADS-B receiving equipment were used for independent comparison against ANOMS 8 outputs, which are based on Mode C Secondary Surveillance Radar. For the sample of flights analysed, the results indicate that the accuracy of ANOMS 8 NTK data is, on average, no worse than ±55 ft in aircraft height and no worse than 30 m in position. These are within the expected tolerances of the radar data. The study has shown no clear evidence of a consistent bias in the NTK height or position data at any of the airports.