PRl Modulation Type Recognition Using Level Clustering and Autocorrelation

In a dense modern electronic warfare environment, there are a lot of radar signals. Pulse repetition intervals of signals received from radars can have various modulations and levels. It is very important to recognize these modulations and to determine their levels in electronic warfare support systems. In this paper, a new method of recognizing PRI modulation type and its levels is proposed for ESM systems. The proposed method is based not only on the properties of the biased autocorrelation function of the PRI sequences but also on the development of a hierarchical clustering method for both classifying PRI modulation types and clustering the PRI levels. This new method is also capable of working in a situation that lost and spurious pulses exist. The performance of the proposed method has also been evaluated in a simulation scenario.