Lunar PVT Estimation Based on Pseudorange and Pseudorange Rate Measurements in Reduced and Extended Constellation Configuration

With the advancement of technological and scientific progress in space exploration, there is currently significant interest in lunar exploration driven by numerous international agencies and companies. In this context, a lunar satellite navigation system, encompassing positioning and telecommunication services, emerges as a critically important component. This article proposes the design of a positioning algorithm that employs the Extended Kalman Filter (EKF) technique, which, in addition to traditional pseudorange measurements, incorporates pseudorange rate measurements. This augmentation proves to be highly beneficial in enhancing the system accuracy. Furthermore, a comparison is presented between the results obtained using a 4- satellite constellation, representing the minimum number of satellites for Position, Velocity, and Time (PVT) estimation, and a more extensive constellation of 16 satellites in Elliptical Lunar Frozen Orbit (ELFO).