Study On Near-Field Time-Frequency Localization Methods Based On Ambiguity Function

With the development of array signal processing techniques, the near-field sourcelocalization technology has increasingly become a focus for researchers. The signalprocessing method of time-frequency analysis technology combination with signalparameter estimation method has also been the attention of the majority of scholars. Inthis paper, the research status of the near-field source localization and time-frequencyanalysis technology are expounded firstly. Several important concepts, time-frequencyrepresentation and properties of time-frequency analysis are introduced. Severalclassical near-field source narrowband and broadband localization methods areanalyzed in detail. And then, for the lack of these methods, this paper usestime-frequency analysis technology for in-depth study for near-field sourcelocalization. This paper reads the DOA estimation methods based on Wigner-Villedistribution for reference, and has proposed several WVD based methods andambiguity function based methods for near-field source localization. The performanceof these methods is verified through simulation experiments.The research results in this paper are support by the following items:The results of this study support the following items:(1) The National NaturalScience Foundation of China (No.60901060).(2) Doctoral Specialized Research Fund(No.200801831028).(3) The National Natural Science Foundation of China (No.61071140).The main work of this paper is as follows:The WVD-MUSIC method for DOA estimation in the far-field is introduced intothe near-field narrowband source localization, the WVD-MUSIC method fornear-field narrowband source localization is proposed. And the new method iscompared with the2D-MUSIC methods. The WVD-Root-MUSIC method is proposedrefer to the Root-MUSIC method based on second-order statistics. These two newmethods use the advantages of the WVD fully. The more accurate localization effectof the near-field narrowband sources is achieved. Introduce the ambiguity function into the near-field narrowband sourcelocalization. Use the ambiguity function matrix replace the covariance matrix of thetraditional methods, propose the AF-MUSIC method and AF-root-MUSIC method.The simulation experiments of the two methods have verified that the performance ofthe two ambiguity function-based methods is better than the WVD-based methods.Introduce the ambiguity function into the near-field broadband sourcelocalization, the AF-ISM method and the AF-CSM is proposed. These two methodsenhance the performance of the near-field broadband source localization. Further,because of the changes of the signals over time can not be ignored, using thecharacteristic that the signal can be represented by time delay and frequency shift inthe ambiguity domain, the AF-CP method for the near-field broadband sourcelocalization is proposed. The method reduces the computational complexity of theconventional method, and has a strong signal resolution.