Abstract: ThemathematicalmodelofBeiDoutriple-frequencycarrier-phaselinearcombinationwasgivenbasedonBeiDousatellitenavigationsystemtriple-frequencydata,andthewavelength,ionosphericerrorandtheobservationnoiseoflinearcombinationwereanalyzedsystemmatically.Intermsofambiguityintegerpropertiesandusedtheintegerlineartransformationmethodasabasis,theoptimizationofthecombinationcoefficientwasrealizedbyMatlab.Byapplyingdifferentcombinationcoefficientstothecycle-slipdetectionbasedoncode-phase,itshowsthatthecombinedcycleslipdetectionwiththesumofthecombinationcoefficientsbeingnot0,ismorethan05weeks,andthelargerthesumofthecombinationcoefficientsis,thegreaterthefluctuationis.ByapplyingdifferentcombinationcoefficientstotheambiguityresolutionbasedonGF-CIRfortriplefrequencyobservations,itshowsthattheresidualvalueofambiguityobtainedbythecombinationofnon-zerocoefficientsbutlongwavelengthsareabout06weeks.Thecorrectambiguityfixedsolutioncanbeobtainedbytheappropriateambiguitysearchmethod,andthiskindofcoefficientscanbeusedinshortbaselineambiguityresolution.

Key words: BeiDousatellitenavigationsystem, triple-frequency, linearcombination, integerlinear-transformation, optimization