Research Of Direction Finding Techniques Based On Passive Radar With High Resolution

Spatial spectrum has advantages of high precision, high resolution and it can break through the rayleigh limited. It could be widely used in the fields of navigation, aviation, radar electronic warfare, civil communication, aquatic sonar and so on. In the field of electronic warfare especially passive direction finding technique, it is highly significant to research spatial spectrum on the current condition of coexistence of old and new direction finding system, the complex electromagnetic environment and the need of multi-signals direction finding.In this paper, based on the actual project application, some typical direction finding methods in passive radar direction finding system are researched especially the methods of high precision and high resolution algorithms.By researching the typical algorithms, a new modified algorithm is proposed with high precision and high resolution. First, it introduces the principle of direction finding technique with phase interferometer. The reason which causes the phase ambiguity and the facts which affect the precision of direction finding are analyzed briefly. And the mathematical model of phase comparison passive radar seeker angle measurement with decoy of no-coherent source is buided by mathematical deduction.Then it is proved that the method of phase interferometer has no effectiveness when there are more than two signals. Second, the spatial spectrum estimation direction finding techniques are introduced. The MUSIC algorithm which is a algorithm of the spatial spectrum estimation is researched in detail. And the typical mathematical model of the signal received by spatial array is given, such as the one-dimensional linear array and solid array. Then by the study of the MUSIC algorithm and the corresponding algorithms, a new modified MUSIC algorithm is proposed through analysis and deduction. The new algorithm has the advantages of higher precision, higher resolution than the MUSIC algorithm and the corresponding algorithms. Third, under the different condition these algorithms are simulated by Matlab, the results could be analysised and compared. Then the conclusion could be got that the performance of the modified MUSIC algorithm is better than the MUSIC algorithm and the corresponding algorithms when the SNR is lower and the snapshots is smaller. Finally, according to the engineering practice the principle of hardware and the design of software algorithm are illuminated in detail. And the whole direction finding system is tested in the laboratory environment, and by analyzing the test data it indicates that the modified MUSIC algorithm has excellent performance and it could provide a biasis for application in engineering. It achieves the desired results.