Active Phased Array Radar Signal Design And LPI Performance Research

With the continuous development of electronic technology, the electronic confrontation becomes more and more intense, especially in the field of radar. Because the LPI(low probability of intercept) radar’s performance is very good, it is widely used in modern radar. Reducing radar signals’ probability of being intercepted becomes more important than before. Today LPI radar’s theory has been developed rapidly. We can design new LPI radar according to these theories.For a better understanding of the LPI radar, the intercepted factor’s concept has been proposed. Through analysis of the main factors affecting the intercept factor, we can find the methods of reducing the probability of being intercepted. Here, we reduce the interception factor mainly by using the waveform design. By blurring function simulation diagram analysis, we can conclude the performances of various modulation signals.Firstly, we analyze a single modulation signal. By analyzing a single modulation signal, we can provide a theoretical basis for future combined signal. With a single modulation signal simulation analysis, we learned that a single modulation signal has many drawbacks. For example, the signal modulation is too simple; it is easy to break the enemy’s investigation and other equipment. For meeting the LPI radar performance requirements, we use a combination of the modulation signal. We also use a combination of the fuzzy function for signal analysis. Through the simulation graph analysis, we can get the performance of a variety of different combinations of LPI signals. We can clearly draw the combined signal combines the advantages of a single modulation signal. And comparative analysis of the results can clearly more superior in all aspects of the performance of the combined signal than a single modulation signal.On the basis of the combined signal is interleaved modulation is proposed a modification of the combined signal. This signal’s structure is more complex than before. Its ambiguity function simulation diagram displays a more obvious "thumbtack-shaped" structure. This shows that the performance of this new combination of LPI signals more excellent. Finally, this thesis uses a very classic time-frequency analysis method to simulate the conditions to crack after being intercepted radar signals. Eventually, we find an effective way to find the low probability of intercept signals.