Determination of GPS real-time precise clock offset

The paper puts forward a new method of real-time precise GPS satellite clock offset estimation. The method adapts the Square Root Information Filter (SRIF) that has benefits of the numerical stabilization, also eliminates the ambiguity parameter through the difference of the epoch which will save the time of the filter consumedly. Based on the above methods, the real-time precise clock offset estimation module is added to the PANDA software which developed by the WuHan University for Position and Navigation Data Analysis. In addition, a examples are analyzed for one week observation from 70 IGS global tracking stations around the world with the software, The results show: The software can achieve the 1HZ's updating clock offset resolution for a global network of GPS tracking stations. Also, the accuracy of 0.2ns is achieved with the software compared with the IGS final products.