LEVEL-SELECTED NONCOHERENT INTEGRATION FOR DETECTING FLUCTUATING TARGETS

In the conventional target signal detection method using noncoherent i ntegration, the integration is carried out using all of the output sig nals from the envelope detector. Therefore, the fluctuations in intens ity of the output signals from the envelope detector form a substantia l component of the pulse signals received. Although desirable, no inte gration is performed for the reflected signal from fluctuating targets . In the conventional method, if high intensity (high SN ratio) pulsed signals are received, even the low intensity (low SN ratio) signals r eceived are unnecessarily used in the integration. Therefore, the aver age SN ratio of the received signals used in the noncoherent integrati on is degraded so that there is a reduced possibility for improvement in target detection probability. In this paper, in order to solve this problem, a threshold is used before noncoherent integration, so that only output from the envelope detector with an intensity exceeding the threshold is used in noncoherent integration. When, in this method, t he envelope detection is linear and the model for the fluctuation of t he target reflection signal is Swerling Case 2, the target detection p robability is found to be improved over the target signal detection me thod using conventional noncoherent integration. (C) 1998 Scripta Tech nica.