Modulation Characteristics Analysis of the LPI Radar Pulses under non-Cooperative Estimation

The Complex Low Probability of Intercept (LPI) radars use different pulse modulation schemes as an effective antijamming feature. A bandwidth based modulation recognition algorithm was proposed in literature, which relies on bandwidths comparison of the intercepted signal and its mth order. This paper develops an improved algorithm to find the optimized data segment length for high performance of bandwidth based modulation recognition algorithm. For real time estimations, only a segment of the long intercepted pulse is processed. The chosen length of the data segment highly depends on the specified range of pulse compression ratio and pulse width. The improved algorithm analyzes the impact of chirp rate on selection of the data segment length and attains high detection performance by proposing a limiting condition. It has been concluded through simulations that if the proposed limiting condition on chosen data segment length and signal’s bandwidth is satisfied, high probability of modulation recognition is achieved.