Fading correlation modelling for troposcatter microwave propagation in array antenna detection applications

摘要

Microwave over-the-horizon (OTH) propagation through troposcatter is a valuable candidate for remote targets detection. Array antenna is promising to handle the contradiction between real-time wide spatial coverage requirement and high antenna gain to capture weak scattering signal. The detection tactics and performance of array receiving systems are significantly affected by the fading correlation between array antennas, but there is no analytical study which considers the fading correlation in troposcatter passive sensing environments for uncooperative targets. In this study, an analytical method based on a scattering transfer function is proposed to derive the channel fading correlation, and the result is a function of transmitter deviation and spatial, temporal, frequency, angular separations of receiving array antennas in uncooperative troposcatter circumstances. In addition, the OTH troposcatter array receiving signal model is derived by exploiting the fading correlation to form the covariance structure of the received array signal, adding up with the signal transmission loss. Existing experimental results validate the derived fading correlations, and the simulation results validate the OTH passive detection performance based on the provided signal model.