The paper describes an adaptive update rate tracking algorithm for use
with electronically steered phased array surveillance radar, and pres
ents results obtained from computer simulations which demonstrate avai
lable performance improvements. The update rate is varied to maintain,
as closely as possible, constant tracker validation region size durin
g target nonmanoeuvre and manoeuvre phases and when missed detections
occur, with the aim of improving tracker performance in clutter. The t
racker combines the interactive multiple model estimator with nearest
neighbour data association and incorporates rapid re-looks when requir
ed. The computer simulations demonstrate the ability of the algorithm
to control the validation region size and to improve track maintenance
in a cluttered environment.