我国中低纬地区GPS定位中的电离层二阶项延迟影响分析与研究

基于消除电离层一阶项延迟的双频载波相位Lc线性组合观测量,利用中国地壳运动观测网络以及国际IGS（International GNSS Service）提供的6个跟踪站连续15天的观测数据,初步分析和研究了电离层二阶项延迟对我国中低纬地区全球定位系统（Global Positioning System,GPS）定位结果的影响.研究结果表明,在电离层二阶项延迟影响下,我国中低纬地区GPS定位结果呈普遍规律性南移的现象,且各地区南偏趋势差异甚微.     

Ionospheric eclipse factor method (IEFM) for determining the ionospheric delay using GPS data

By establishing the ionospheric eclipse factor (IEF) λ of the ionospheric pierce point (IPP) and its ionospheric influence factor (IFF) λ, and combining λ, λ with t of IPP, a new method of modeling high-precision ionospheric delay using GPS data-ionospheric eclipse factor method (IEFM)-is presented in this paper. The IEFM can effectively select the proper ionospheric models to model the total electron content (TEC) with different changes corresponding to annual, seasonal and diurnal variations. Initial experimental results show that the correction precision of ionospheric delay modeled by the IEFM seems to be close to that of using L3 GPS observations to directly correct the corresponding ionospheric delay.     

A generalized trigonometric series function model for determining ionospheric delay

A generalized trigonometric series function (GTSF) model, with an adjustable number of parameters, is proposed and analyzed to study ionosphere by using GPS, especially to provide ionospheric delay correction for single frequency GPS users. The preliminary results show that, in comparison with the trigonometric series function (TSF) model and the polynomial (POLY) model, the GTSF model can more precisely describe the ionospheric variation and more efficiently provide the ionospheric correction when GPS data are used to investigate or extract the earth's ionospheric total electron content. It is also shown that the GTSF model can further improve the precision and accuracy of modeling local ionospheric delays.     

Study of the ionospheric TEC using GPS during the large solar flare burst on Nov. 6, 1997

Using the data from 15 global positioning system (GPS) stations scattered between 28° N—45° N and 90° W—77° E we obtained the total electron content (TEC) variations with time during a large solar flare. The results indicated that the flare makes the TEC of ionosphere increasing in a large spatial area. The amounts of the TEC enhancement are mainly determined by the local time of subionospheric point, and the largest TEC enhancement is about 2.5 TECU. It is also concluded that the TEC enhancement is not symmetrical about the local noon time, the TEC enhancement values during morning hours are larger than those of the afternoon hours.     

The diurnal variations, semiannual and winter anomalies of the ionospheric TEC based on GPS data in China

With the spherical harmonic (SH) function model and the dual frequency GPS P code phase data from the Crustal Movement Observation Network of China (CMONOC) during the period from year 2000 to 2002, time series of total electron content (TEC) in the area of China is calculated. The diurnal variations, semiannual, and winter anomalies of the ionosphere in the area of China are analyzed and discussed, especially according to the results of year 2001.     

实时动态定位技术在地籍与房地产测量中的应用初探

实时动态（RTK）定位技术是GPS测量技术发展中的一个新突破，以其精度高、速度快、费用省、操作简便等优良特性被广泛应用于国民经济建设的各个测绘领域。RTK定位技术已成功应用于地籍与房地产专业测量的控制测量与碎部测量，并充分展现其先进性、高效性和极其广阔的应用前景。