A Gram-Schmidt SLC Controlling the Number of Auxiliary Antennas to Preserve Desired Signals.

In the SLC (sidelobe canceler) which automatically suppresses the interference signals received by the sidelobe of the main antenna, there is a problem of suppression of the desired signal in addition to the interference signal if the desired signal power in the auxiliary antenna is larger than the receiver noise power and if the number of received interference signal is smaller than that of the auxiliary antennas. In this paper, an SLC is proposed in which the number of auxiliary antennas is adjusted automatically to be equal to that of the interference signals so that the problem of suppression of the desired signal is prevented. It is assumed here that both the desired signal and the interference signals have narrow bandwidths. In this SLC, with a view to adjusting the number of auxiliary antennas and the weights at the same time, the Gram-Schmidt SLC (GS-SLC) is used so that a sudden change of the input-output signal power ratio of the Gram-Schmidt processor is detected and the number of auxiliary antennas are made to coincide with that of the received interference signals. By way of a computer simulation, the fundamental characteristics of the present GS-SLC are evaluated. It is confirmed that the desired signal preservation property is improved in comparison with the conventional SLC. [ABSTRACT FROM AUTHOR]