Use of aircraft-derived data to assist in ATC tracking systems. Part 1: Accuracy and theoretical considerations

At present, aircraft tracks for ATC purposes are formed by processing SSR data only, but the introduuction of systems such as ADSEL and DABS makes it possible to transmit to the ground station measurements available on board to assist in radar tracking. The two main areas of application are to improve the performance of present trackers during straight-line flight and during manoeuvres. The accuracy requirements of aircraft-derived data are examined from a theoretical viewpoint and from recordings made onboard aircraft flying scheduled services. One filter capable of tracking manoeuvres and another filter capable of estimating the wind speed and using roll-angle, TAS and heading measurements are constructed.