Study On Measurement, Detection And Interference Suppression Technologies Of Instantaneous Polarimetric Radar

As one of the development tendencies of current new radar system, the polarizationinformation is used to improve the radar abilities, such as detection, anti-jamming andrecognition, etc. The conception and theory of instantaneous polarization provides a pow-erful theory tool to represent and process the variable, wideband and dynamic polarizationinformation. It also motivates the manufacture and development of new full-polarimetricradar system. The simultaneous full-polarization measurement radar, which uses the in-stantaneous polarization theory and technology to process the information, can be calledinstantaneous polarization radar (IPR). Because the IPR can achieve the measurment ofentire polarization scattering matrix (PSM) through one observation and process the PSMusing instantaneous polarization theory, it is more powerful in measurement and process-ing of the polarizatoin information. Therefore, it has the obvious advantage in target de-tection, anti-jamming and target reorganization comparing with traditional polarimetricradar. Motivated by the development of the IPR system, this dissertation focused on themethodsofpolarimetricmeasurement,polarimetriccalibration,polarimetricdetectionandpolarimetric interference suppression. Part of the research results was testified by the out-door tests.Chapter 1 summarizes the development of the polarimetric radar theory, the polar-ization measurement system and the key techniques of polarimetric radar. The conceptof IPR is given; the unresolved problems in the IPR development are listed. The majorresearch topics of this dissertation are summarized.In Chapter 2, the PSM measurement method for IPR is studied. To resolve the prob-lem of signal selection and parameter design of IPR's transmitting signals, the evaluationmethodofPSMmeasurementperformanceofthetransmittingsignalsisprovidedbasedonthe instantaneous polarimetric ambiguity function matrix (IP-AFM), which provides thetheory foundation of the signal selection and parameter design for polarimetric radar. Tosuppress the measurement error that is produced by the cross-correlation between twoorthogonally polarized transmitting signals exists in the traditional PSM measurementmethod, the new PSM measurement method based on IP-AFM is proposed. To achievethe new PSM measurement, the IP-AFM estimation method is introduced.In Chapter 3, the calibration method for IPR is studied. Because the spatial polar-ization characteristics of antenna are neglected by the traditional polarimetric calibrationmethod, the new polarimetric calibration methods based on mental sphere or standard signal transmitter are introduced. With consideration of the spatial polarization charac-teristics of antenna, the PSM measurement error is calibrated by the new methods. Thecalibration difficulties are reduced, the calibration precision is improved. By studying theangle of arriving (AOA) measurement error, which is associated with the polarization ofthe received signals, the causation of the coupling measurement error between polariza-tion and AOA is analyzed. The calibration method for this coupling measurement error isintroduced.In Chapter 4, the target detection method for IPR is studied. The PSM measure-ment result of the received signals is assumed to be reciprocity in the traditional detectionmethod. Because of the influence of the spatial polarization characteristics of antenna,this assumption can not be satisfied in practice. With consideration of this influence, theoptimal polarimetric detection algorithm of stable target in Gaussian noise is studied, theengineering realization method of this algorithm is given. The optimal detection methodsof fluctuant target in Gaussian noise and stable target in non-Gaussian noise are also stud-ied. The detection performance is improved because of the usage of the cross-polarizationsignals under the non-reciprocity assumption.In Chapter5,theanti-jammingmethodforIPRisstudied. Toresolvetheproblemthatthe performance of traditional polarimetric filter is dropped when the jamming polariza-tion is changing, the instantaneous polarimetric filter (InPol-filter) is introduced. ThroughInPol-filter, theinterferencethatpresentsinthetime-frequencyareaofthetargetbackscat-tering can be detected and suppressed automatically after the polarization estimation. Andthesuppressionperformanceofthevariablypolarizedjammingisimproved. ThePSMes-timation method based on the outputs processed by polarimetric filter is given. Take thejamming in midcourse of missile trajectory as the typical example, the polarization track-ing filter to suppress the polarization modulation jamming is introduced. The jammingsuppression performance is improved by the polarization tracking filter comparing withthe traditional polarization filter with invariable receiving polarization. The decoy distin-guishmethodoffull-polarimetricmodulationdecoyarealsostudied,thedecoydistinguishability of IPR is improved.