Spread spectrum signal detection using a cross correlation receiver

A technique is presented for the detection of very low power spread spectrum signals with high resolution direction finding, by cross correlating the outputs of two spatially separated receivers and forming the "time domain filtered cross spectral density" (TDFCSD). Detection is achieved by threshold detection within the amplitude of this TDFCSD, while direction finding is achieved by phase slope estimation. Results are presented to show that the initial cross correlation can be performed by a time integrating acousto-optic correlator, enabling real time operation for wide receiver bandwidths.