Research On The Mitigation Technology Of CMMB Navigation Enhance System

Multipath interference signal causes the deviation, resulting in signal to noiseratio drops badly, affecting the system reliability and accuracy in CMMB navigationenhance system. This paper focused on the adaptive channel equalization technologyand signal processing technology to resolve the multipath effect on positioningeffect.Adaptive channel equalization essence is using the inverse function ofmultipath channel transmission function to compensate the multipath signal causedby the distortion, mainly introduced the algorithm of adaptive equalization andchannel estimation. Adaptive equalization algorithm part mainly analyzed the LMSalgorithm and RLS algorithms, two algorithms are able to track the channel changes,suppressing noise. Based on RLS algorithm adaptive channel equalizer convergencespeed faster than based on LMS algorithm equalizer, amount of calculation is alsoslightly larger. In the multipath channel estimation part mainly analyzed the LSalgorithm and LMMSE algorithm, LMMSE channel estimation algorithm need toknow the channel statistics and statistical characteristic of noise, the mean squareerror of the estimated result is superior to that of LS channel estimation of meansquare error of the LMMSE algorithm, but requires a matrix inverse operation,operation increases with the matrix dimension.Signal processing technology mainly analysis the multipath channel code andcarrier tracking performance, and the two signal processing multipath algorithm.Pseudo code phase tracking error related to the pseudo code correlation interval, themultipath signal attenuation and multipath signals phase delay; with the change ofcarrier phase, the tracking of the carrier phase error similar to sinusoidal variation.Signal processing part discusses the narrowband tracking technology and Strobetechnology. Narrow correlator is to delay locked loop for the foundation, can bereduced effectively and reduce tracking error, position error in the presence ofmultipath and noise-related to the narrow correlator, Strobe technology only changeearly late correlation correlation interval of the traditional receiver, and it’s moreresistant to multipath ability than narrow correlator.This paper through the corresponding theoretical analysis, using MATLABsimulation tool to analysis the anti-multipath performance in different multipath environment, simulation and result analysis of the adaptive channel equalizationtechnology and signal processing technology illustrates effectiveness and feasibilityof anti-multipath interference.