Research On The Data Processing Method Of High Dynamic GPS Positioning Of Re-entry Spacecraft

In this thesis, considering engineering application demands, analysis and research work are taken aimed to several key points of GPS applications on board of re-entry spacecrafts . Moreover , the results of this thesis are simulated and validated via advanede simulation and modeling platform.First , proper way of GPS positioning are selected according to the high dynamic flight characters of re-entry spacecrafts, such as high distance from the earth, high velocity and far awy from the launching point. We choose single point pseuodorange positioning method for the mission because the requirements for hardware are easy to access, the costs are fewer than other methods and the accuracy can meet the needs of realized work.On the study of the high dynamic flight characters of re-entry spacecrafts, positioning method of dynamic correction is brought forward. This method is based on the Bent Ionosphere model and the coefficient of dynamic correction is introduced into traditional cosine correction model to achieve dynamic correction of Ionosphere delay. So the position error of over correction can be overcomed.According to the non-real time phenomena of high dynamic flight GPS application, Kalman predictive filter is designed to process the positioning data so as to reach the real-time demands.Then, GPS error sources and their influences on positioning accuracy are analyzied. Moreover ,we simulated the GDOP changes along the whole trajectory to decide the best poiont for GPS receiver to start working.Finally , the dynamic correction method and predictive, filter are simulated and validated via advanede simulation and modeling platform. The results show that the accuracy can be improved above 150 km after using the dynamic correction method and the processed data can meet real-time requests after being filtered.The results and simulation methods can be used for reference in engineering practise.