Effects of birds on radar tracking systems

Tracks from birds, or flocks of birds, present a problem to designers of land and sea-based radar tracking systems, since the users of these systems are generally uninterested in such tracks and would prefer them to be removed from the synthetic track picture. The difficulties are compounded by the fact that users, while wishing to remain ignorant of bird tracks, would still like to be informed of tracks of other fairly slow flying objects such as light aircraft and helicopters. In naval or coastal radar systems it is usually also a requirement to be able to form tracks on moving ships and boats of all descriptions, some of which can move at similar speeds to birds. For operational reasons there is a trend towards radars being made more sensitive, and a side effect of this is to increase the chances of birds forming a significant proportion of all tracked objects. This paper examines some of the characteristics of bird detection and flight and analyses examples of surveillance radar recordings affected by bird tracks.