Multifunctional receiver using an acousto-optic spectrum analyzer: an example application and results

Low probability of intercept (LPI), spread-spectrum signals are becoming commonplace in both communication and radar systems. Cooperative receivers process these signals to provide large gains in the output signal-to-noise ratios (SNRs). Given the low signal power expected during reception and the lack of a priori signal knowledge, intercept receivers have difficulties in providing adequate detection of LPI signals. This detection problem is compounded when high power, narrow-band interference is simultaneously present with the LPI signal. A 512-channel acousto-optic spectrum analyzer is used in conjunction with digital processing to implement an autocorrelation-type receiver with interference rejection. Although difficult to implement in radio frequency (rf) or digital electronics, acousto- optic spectrum analyzers may provide a practical solution with sufficient dynamic range for the intercept application. Implementation and algorithm considerations are provided as well as simulated results. Initial experiments confirm LPI signal detection when the signal is minus 5 dB relative to noise and minus 40 dB relative to multiple narrowband interference sources.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.