Modified MLE-Based GNSS Signal Open Loop Tracking Strategy for Flight Missions in the Space Service Volume

Abstract

Already today an increasing number of space flight missions all over the world have GNSS spaceborne receivers embarked. To inspect the service performance of SSV receiver, we build a reference assumption model on the basis of optimal closed loop design. But the stable condition of tracking loop proves that our reference assumption receiver is incapable in weak-signal and high-dynamic environments. Then different tracking loop structures are compared, and open loop structure seems superior to other schemes in SSV applications. With non-coherent integration MLE algorithm, the coupling effect between carrier phase estimation and Doppler frequency estimation is removed. At last, a HEO flight mission scenario is established while a certain BDS MEO satellite serves as the signal source, and the simulation results clearly reflect the advantage of our proposed OL tracking strategy over conventional CL tracking scheme.