Evaluation on the Precision of Klobuchar Model forBeiDou Navigation Satellite System

Objective At present,China’s BeiDou Navigation Satellite System(BDS)has completed a constella-tion of regional network.The system provides a set of ionospheric parameters for the BeiDou Klobu-char model every two hours.Using a high precision GIM model for CODE as a reference,the perform-ance of ionospheric parameters and positioning assessment of BDS are evaluated.The data shows thatcorrection accuracy is generally 70% or more,the correction error in the Northern Hemisphere isabout 1.5meters,and 3.5meters in the Southern Hemisphere.In the Northern Hemisphere,the cor-rection precision in mid-latitude region is higher than high-latitude and low-latitude region.The preci-sion for BDS SPP on frequency B1is about 3meters in the horizontal direction,and about 7meters inthe vertical direction using BDS Klobuchar model.In comparison to use GPS Klobuchar model,preci-sion increased by about 10percent,especially in the vertical direction.