Canceling Strong Narrowband Main-beam Interference

In a generalized sidelobe canceler using normalized least mean square adaptation, interference coming in on sidelobes can be mitigated when using a small adaptation stepsize. In that case, any interference arriving from the main beam look direction will be viewed as a desirable signal, and therefore passed on. Previous studies have identified narrowband interference scenarios where interference mitigation is enhanced by non-Wiener effects in normalized least mean square adaptive filtering using existing filter structures. In this paper we seek to further extend narrowband interference mitigation by expanding the adaptive filtering structures to better utilize the information responsible for non-Wiener effects. While in the generalized sidelobe canceler adaptation takes place in the spatial domain of auxiliary beams, here we seek to incorporate the temporal dimension as well. The latter will be applied to the auxiliary beams and the main beam, or to the error signal of the generalized sidelobe canceler. The performance of the space-time adaptive processor operating on the temporal signals from the main beam and auxiliary beams simultaneously turns out to be comparable to that of a temporal smoothing stage operating on the generalized sidelobe canceler error.