Algorithm Research Of Ionospheric Clutter Extraction And Project Realization

High frequency ground wave radar (HFSWR) has many excellent properties, forexample, it can detect hidden targets, and it can reach somewhere out of sight,extensively used in many areas because of its superiority. In the course of radardetection, the existence of the clutter can not be ignored as an interfering factor,which would enhance the background noise affecting target recognition, making thenormal operation of the radar can not work. So as to minimize the impact generatedby clutter, first, suppress clutter naturally, meanwhile, for different radar frequency,evaluate the pollution level of clutter for corresponding frequency, and theinformation is helpful for frequency selection. So the research is from two aspects:one is about how to accurately identify the clutter, the other is evaluating the pollutionlevel of clutter.This paper mainly describes how to detect and identify ionospheric clutter, andthen describes the design of the process in detail, at the same time, for the pollutionlevel of ionospheric clutter, discuss how to evaluate it. The main contents are asfollows:For HFSWR, present its echo signal components in detail, analyze variouscharacteristics of clutter thoroughly. Sea clutter is explained how to produce, at thesame time introduce application of sea clutter in some area, then elaborate on the insand outs of ionospheric clutter, explain its route after launch, and introduce its relatedfeatures, such as the transmission characteristics, the distance and Doppler domainproperties.On range-Doppler profile(RDP), for ionospheric clutter, introduce how to detectit, and test the method by the actual data. The main steps of detection andidentification: first, detect and remove the first-order sea clutter, so that the followingoperation is not affected; second, segment the RDP by setting up a threshold, then abinary image appears, and save the location where dominant signal exists; third,process the binary image, then we can get the final results of ionospheric clutterdetection and recognition. for the RDP Generated from the actual data, the results areideal with the method for processing.About the pollution level of ionospheric clutter, study its assessment methods,and briefly describes the results of the assessment used in radar frequency selection ofideas and the main steps. Based on the results of detection and identification of ionospheric clutter, define several physical quantities to describe the pollution level ofionospheric clutter. After that, one evaluation method exists considering the extent ofthe individual factors that affect the availability of ionospheric clutter contaminationassessment method based on a single factor, then another evaluation method existsconsidering a number of factors available to assess the extent of noise pollution in theionosphere based multi-factor approach. In this thesis, the two assessment methodsare applied to the actual data. Finally, introduce how to apply the assessment results toradar frequency selection briefly.Based on the theoretical support and simulation experiments above, finial theproject implementation of ionospheric clutter detection and identification of the entireprocess and the level of noise pollution in the ionosphere assessment. Introduceclutter and information processing software modules, indicate its relationship withother system modules, and divide the module into several sub-modules forintroduction. Finally, finish the project realization of the entire clutter extractionprocesses by the actual data, and assess the pollution level of ionospheric clutter, thenwe can get the results of project implementation.