Receiver design for non-cooperative passive detection system

A novel receiver system for non-cooperative passive detection is proposed and the analogue cancellation of the radio frequency is used. In the system, the reference signal is processed by the attenuator and the phaser before sampling to cancel the direct signal from the received antenna, so that the quantizing noise power is reduced and the detection capability is enhanced. The parameter adjust algorithm is also deduced. The canceling methods are discussed when the unideal factor of the device is known or unknown. The result proves that when the unideal factor of devices is unknown, the parameter solved by the iteration is convergent to that when the unideal factor is known. The capability of receiver system restraining the direct signal is also discussed when the receiver adopts actual devices. Compared with the traditional receiver system, theoretical and simulation results of the receiver system can detect the weaker target by the follow-up digital signal processing.