Ionospheric behavior and its effect on positioning during the solar eclipse of 22 July 2009

On 22 July 2009, an exceptionally long total eclipse of the Sun was visible within a narrow corridor that traverses the Eastern Hemisphere.A geomagnetic storm synchronized with solar eclipse and led to the complexity of the ionosphere variations.GPS observations derived from Chongqing CORS, Wuhan CORS, IGS stations such as WUHN and SHAO in Moon's umbra, and other IGS stations in Moon's penumbra.Comparing the TEC variations on three consecutive days, and based on location and time, the depression of TEC amounted to (1～4) TECU.Meanwhile, in real time point positioning, horizontal accuracy didn't have remarkable changes, but vertical accuracy declined up to several meters.And in real time baseline positioning, horizontal accuracy still reached to centimeter level, and vertical accuracy to decimeter level in the beginning of solar eclipse.But the geomagnetic storm occurred in the last of solar eclipse lead to the decline of horizontal accuracy to decimeter, and vertical accuracy to meter.