The Fitting And Equalization Technology Research And Design In Navigation Receiver RF Channel

In order to improve anti-jamming capability and the received signal quality of the satellite navigation system,ground navigation centers typically employ an array antenna and multi-channel RF front-end to receive satellite navigation signals.But the uncertainty of the radio channel,the drift of each RF channel circuit parameters caused by the temperature and humidity and other factors can easily lead to channel inconsistent,that is channel mismatch problem,RF channel mismatch will seriously affects the array signal processing performance.This thesis focuses on four issues including the mechanism of the satellite navigation receiver channel mismatch,channel characteristics fitting,mismatch channel equalization and RF channel design and realization for research.Firstly,the theoretical model of the RF channel inconsistent is established,and then the RF channel inconsistent mechanism which affects the array signal processing performance is theoretically analyzed.Secondly,the thesis studies the channel fitting method based on measured data and mismatch models.A RF channel mismatch characteristic fitting method based on a new segmentation strategy and least squares algorithm is proposed,which lays the foundation for the next channel equalization.The mismatch model based intersection of frequency spectrum is built based intersection of frequency spectrum and filter banks technology.It can divide the broadband channel into several sub-channels in accordance with the requirements of indicators,and then design filters based on the amplitude-frequency characteristics of each sub-channel,in order to achieve purposes of reducing filter order and refining description of channel mismatch feature.Thirdly,the thesis studies channel equalization method for RF channel inconsistent from the signal level.On the basis of the intersection of frequency spectrum,a sub-channel variable step size equalization method is proposed.Its basic idea is dividing the broadband signal into several narrow-band signals with narrowband signal processing algorithms to complete wideband signal processing.Comparing with the traditional LMS equalization algorithm,it will not only reduce the length of equalizer weights,but also reduce the algorithm complexity.Finally,this thesis provides an optimized implementation of RF channels.RF channel band-pass filter,and sub-modules of the RF channel are designed and realized by hardware,and the performance of the designed RF channel is also verified.