Accuracy Assessment of Klobuchar Model and NeQuick Model in China

Klobuchar model is used for ionospheric delay correction by GPS,and NeQuick model is used by the Galileo system with the same purpose in the single frequency mode.We consider ionosphere products that are post-processed by Center for Orbit Determination in Europe as reference,taking advantage of vertical TEC data provided by Klobuchar and NeQuick model for the 15 GPS basic stations in Crustal Movement Observation Network of China from the year 2000 to 2008.And the eight coefficients for Klobuchar model will be provided by CODE and GPS navigation message respectively,we analyze the application of the two models in the Chinese region.① It is more obvious that the bias of Klobuchar model will increase with respect to the lowering of latitude.Both NeQuick and Klobuchar model of GPS broadcasting are observed to have stronger links to the periodic variations of solar activities.② There are relatively large standard deviation which has excluded bias,in the two models in peak year of solar activity and low latitude region.yet on the whole,NeQuick model produces the least standard deviation.③ The fact that the two models,when applied to the area of China,show regular variation depending on solar activities and latitude,provide with the possibility and basis of the further optimization and improvment of them.