Detection of Birds by Radar

Abstract : A severe threat for modern aircraft are bird strikes. Especially during bird migrations, which happen twice a year in Holland, the risk of bird strikes can be high. The damage as a result of a bird strike can be very high, and may even result in loss of aircraft. Therefore it is necessary to measure bird densities in the neighbourhood of airports and along air traffic routes. These densities can be measured using a radar system. In this chapter some notes on such a radar system will be given. Modern radar systems have the ability to detect and track targets with a very low Radar Cross Section. Therefore any bird could initiate a track. If this happens, the radar operator is burdened with the task to discriminate between echoes and tracks of real targets and those of birds. Classification of birds and other air targets such as aircraft and helicopters allows for distinction between these targets so that the number of bird tracks can be reduced. During the National Technology Project (NTP) on Advanced Radar Techniques for Improved Surveillance and Tracking (ARTIST) trials were conducted in September and October 1992. Subsequent to these trails the three available systems were used for observing birds. Bird phenomena have been studied by radar by a number of investigators. See for example Vaughn 1, which reviews the literature that describes birds and insects as radar targets. The observed phenomena provide information about the specifications of radar systems for bird observation. The following subjects are investigated: (1) Radar systems for bird observations: Birds can be detected by several types of radar: Pulse radars give the position of the bird. Continuous Wave radars give the doppler shift of the body and other moving parts of the bird.