Adaptive α-β tracking filters for ATC applications

In the ATC environment the characteristics of aircraft motion require adaptive filters to implement the tracking function of a TWS system, while the system processing constraints require low-complexity computational algorithms. adaptive α-β tracking filters are therefore a convenient solution to the problem. In this paper four alternatives to the implementation of adaptive α-β tracking filters are presented, based on the selection of an appropriate set of values of the filter coefficients and on a suitable switching strategy among those values depending on the comparison between radar measurements and filter outputs. Their computational load is much lower than for adaptive Kalman filters, whose relevant structures are also discussed for comparison. The performance of the four proposed adaptive strategies is presented on the basis of computer simulations applied to two typical aircraft flight paths and compared with the performance of α-β non-adaptive tracking algorithms.