Radar pulse repetitive paterns detection

Pulse Repetition Interval (PRI) is an important parameter in the recognition of pulsed radar signals because of its distinctiveness. Pulses time of arrivals (TOA are PRI sources. Depending on the radar function various PRI modulations are used. So PRI pattern requires the estimation of the numerous calculations to determine its values correctly. PRI complexity makes it as a distinctive parameter for electronic intelligence, under condition that the signal´s parameters are estimated ambiguously and repeatedly for different series of measurements. Significant difficulty of analysis is an existence of distortions arising from the propagation properties and signals interference under measurement. In the literature much attention is paid to seeking ways to solve the problem. Proposed, are various algorithms showing good properties for certain types of modulation. They are ineffective for others PRI types. They can be successfully used in ELINT systems, while in the ESM devices, where full automation is required, their usefulness is limited. The paper presents some aspects of PRI analysis on the base of simulated and real signals. Also presented is a modification of the algorithm based on the use of autocorrelation function in the analysis of PRI. The proposed solution allows for more efficient analysis of long sequences of periodic changes in PRI (stagger, complex, dwell and switch) in terms of having a relatively short measurement sequences.