中文摘要：

采用单频星载GPS实测伪距和载波相位观测值,结合不同的电离层延迟改正模型进行模拟实时定轨实验,分析单频实时定轨的精度。不同轨道高度的低轨卫星实验结果表明,在卫星轨道较高（500km以上）时,使用单频伪距观测值与改进的Klobuchar模型,实时定轨位置精度可达0.86m（三维RMS）,速度精度可达0.9mm/s,接近甚至优于双频伪距实时定轨的轨道精度;使用单频码相无电离层组合观测值时,实时定轨位置精度可达0.54m,速度精度可达0.55mm/s。采用合适的电离层延迟改正模型,廉价的单频星载接收机可应用于微小卫星的实时定轨。

英文摘要：

The ionosphere range delay is one of the dominating error sources for the space-borne GPS single-frequency real-time orbit determination.When corrected by ionosphere correction models,the residual error has obvious influence on the accuracy of real-time orbit determination.In this paper,we use single-frequency pseudo-range and carrier phase measurements,calculated with two different ionosphere correction models,and then we analyze their impacts on the results.Our study shows that when the altitude of the low earth orbit（LEO）satellites is 500 km or higher,the position and velocity accuracy（3DRMS）are 0.86 mand 0.9mm/s,which is close to the accuracy of dual-frequency pseudo-range real-time orbit determination. When using the group and phase ionosphere correction（GRAPHIC）,the position and velocity accuracy can be 0.54 mand 0.55mm/s.Therefore,when an appropriate ionosphere correction model is selected,low-cost single-frequency space-borne GPS receivers can be used in real-time orbit determination for micro-satellites.