Study On Technology Of Wideband Multichannel Phase Delay Measurement And Correction

Since to get more subtle information of the target can not only improve the ability of the identification of the target but also offer more accurate location, the radar usually firstly uses wideband signal which has a high ranging resolution. Wideband Digital Array Radar, which shows the meaning of its name, refers to the very fully digitalized array antenna which uses wideband signal to realize both the transmission and reception of the signal with the technology of digital beam-forming. At the same time, Wideband Digital Array Radar, as a new favorite, has so great development potential that scholars at home and abroad are attracted to do relative studies on Wide Digital Array Radar as many as they can. However, with the development of the digitalization and the wide-bandization of the radar, it appears many technical problems, one of which as the key one is the existing delay between channels of the array. And this very delay among channels can cause the mismatching among channels leading to affect the quality of the digital beam-forming. As a result, this thesis focuses on studying on how to measure and correct the multichannel delay.This thesis first introduces how the DAR works and some key technologies of DAR, and then discusses on the development history and the research status of the technology of the wide-band multichannel delay measurement and correction.And then this thesis first presents the basic conception of the wideband signal, and then focuses on introducing the wideband Linear Frequency Modulation signal. Furthermore, this thesis introduces the channel delay and then analyses how the channel delay produces. At last, this thesis presents how the delay affects the digital beam-forming as well as introduces the foundation of the wide-band signal model of the delay.Based on the technology of De-chirp, this thesis introduces how to measure the multichannel delay which comes from the mismatching of analogue devices of digital T/R components. And then this thesis analyses principles, parameter determination as well as performances. Finally, on the basis of the platform of MATLAB, this thesis also does some simulations in order to prove the feasibility of the measurement method.During the last chapter, this thesis introduces the principles of fractional delay filter and designs the fractional delay filter from those two aspects of Finite Impulse Response(FIR) filter and Infinite Impulse Response(IIR) filter. With the designing methods of fractional delay filter such as Weighted Least Squares method, Maximum Flat method and so on, this thesis does some simulations on the designing methods of fractional filter with MATLAB as well as puts the very designing methods of the fractional delay filter into correcting the channel delay that was produced in the third chapter. And then from the aspect of the variable fractional filter, this thesis presents how to design the FIR variable fractional delay filter based on the Farrow structure as well as the variable fractional all-pass filter based on the Gathering structure. At the same time, this thesis does necessary relative simulations on the above fractional delay filters with the platform of MATLAB. Finally, this thesis chooses variable fractional all-pass filter to correct the multichannel delay with MATLAB simulations in order to prove the feasibility of the correction method.