Calculations concerning angular jamming of missiles


  • Falk Lars

Publish date: 2005-01-01

Report number: FOI-R--1653--SE

Pages: 38

Written in: Swedish


Crosseye jamming is a method intended to deflect a missile sufficiently to make it miss its target. Two antennas located on board a ship or aircraft create a false target located outside the real target. The false target is created by two copies of the radar signal which are re-emitted out of phase with slightly different amplitude. The method is sensitive to small errors in amplitude and phase and may be affected by scattering from the surrounding terrain, in particular reflections from water. It has previously been shown within the projekt that the effect of scattering can be eliminated if the crosseye system is reciprocal. This report provides a quantitative analysis of the conditions required to make crosseye jammimg work in practice. The construction is analysed to select parameters that will give a deflection sufficient to protect a platform. The selected construction is compared with proposals previously described in the literature. The effect of scattering can be estimated by appying the principle of reciprocity to an ideal monopulse antenna employed in a target seeker directed towards a crosseye system. The calculated parameters prove that it is possible to construct a crosseye system using solid state amplifiers and antennas with limited gain.