PULSE REPETITION INTERVAL CORRELATOR UTILIZING ZERO MEAN MATCHED FILTERING AND DIFFERENCE MINIMIZATION CORRELATION

摘要

A system to perform real time temporal correlation on pulsed and periodic signals. Application is to systems which perform PRI analysis of signals and provide signal gain as part of the correlation process. Correlation is performed in two stages, the first conditioning the signals for correlation using the zero mean, PW matched filter and the second performing temporal correlation using the difference minimization PRI correlator. The primary purpose of the filter is to minimize any DC signals before they reach the correlator. If DC signals reach the correlator, they correlate up at every PRI setting and on every temporal point, resulting in false detections and can block actual signals from detection. The filter also provides some gain for signals with pulse widths greater than one temporal cell. After conditioning with the filter, the data is correlated using a difference minimization correlator. The primary purpose of the correlator is to correlate signals of the selected PRI while rejecting signals which are not of the selected PRI. The correlator tracks pulses which are not aligned to temporal cell boundaries by a decision based upon the minimum difference between the normalized output, the current input and a time shifted input. By minimizing the difference, the noise is correlated with noise and the signal is correlated with signal. Pulse edges of the signal are maintained while maintaining the noise growth to a minimum.