Performance of a sliding window detector in a high interference air traffic environment

Target detection and azimuth determination is accomplished in the enroute air traffic control radar beacon system with a sliding window processor. Due to missed replies and the presence of interference the center mark is not deterministic, and can only be described in a statistical sense. A novel approach is taken which introduces a class of input/output sequences that establish the validity of a target start. An expression for the center mark distribution is developed around these "valid chains". The resulting analytic tool is used to examine sliding window performance in several current and projected ATC environments and is available to determine optimal sliding window parameter settings. An important finding is that the centermark estimate is biased; for low reply probability or high interferencerates this term is a significant source of error.