利用CORS进行格网化电离层TEC实时监测

Real-time monitoring of regional ionospheric TEC based on CORS with grid technology

为了实现对区域电离层的实时监测，利用连续运行参考站观测到的双频GPS数据提取电离层总电子含量（TEC）信息．根据卫星和接收机硬件延迟在一定时间内比较稳定的特点，利用前一天计算的硬件延迟值来修正当日卫星传播路径上的总电子含量值，从而获得实时的电离层总电子含量．由此建立单历元多站多项式模型，结果表明：当基站间距离平均约为250km时，由7个基站共同建立的实时模型内外符合精度平均优于0．8TECU（1TECU=10抛电子数／m2），将实时模型计算的电离层延迟改正信息应用于静态单频PPP定位中，点位精度能够达到0．3～0．4m，与不进行电离层延迟改正的单频PPP定位结果相比提高80％左右．因此，进一步结合格网技术，可以实现区域电离层总电子含量的实时监测．

In order to achieve the real-time monitoring of regional ionosphere, the ionospheric total electron content （TEC） is extracted from the dual-frequency measurements provided by the continu- ously operating reference stations （CORS）. According to the stability of satellite and receive differ- ential code bias （DCB） during a certain period, the real-time ionospheric TEC is calibrated by using differential code biases of the former day. Thus, the real-time multi-station polynomial TEC model can be established. Results show that the average internal and external accuracy of the model estab- lished by all the seven reference stations can be better than 0.8 TECU （ 1TECU = 1016electrort/m2 ） when the average distance of the stations are about 250 km. With the availability of the ionospheric delay corrections calculated by the real-time model, the single precise point positioning （PPP） point accuracy can reach 0.3 to 0.4 m, which improves 80% compared to the single PPP without iono- spheric delay corrections. As a result, the real-time TEC monitoring of a certain area can be achieved with the combination of the grid technology.