INS/GNSS Integrated Rover Navigation Designed With MDPO-Based Dual-Satellite Lunar Global Navigation Systems

Aiming to provide navigational framework to upcoming early lunar exploration missions by lunar rovers, interests in robust and low-cost global satellite navigation systems (GNSS) around the Moon are growing more than ever before. In response, dual-satellite lunar global navigation systems (LGNS) based on Multi-epoch Double-differenced Pseudorange Observation (MDPO) algorithm was proposed in our earlier work. While the MDPO-based dual-satellite LGNS can provide reasonably high positioning accuracy at an order of several tens of meters within a one-minute observation, the positioning calculation is only available when the two navigational satellites are in user's view. This limitation can be overcome by integrating other navigational sensors such as inertial navigation system (INS) and compensating for user's positions in the absence of GNSS signals. The main objective of this research is to provide an integration model of INS and MDPO-based dual-satellite LGNS measurements and quantitatively show the benefits of the proposed integration by numerical simulations. More specifically, the major contributions of this paper are three-fold: 1) proposed a mathematical model of INS/GNSS integration adopted for the MDPO algorithm, 2) developed a numerical simulation that combines INS measurements and dual-satellite LGNS measurements, and 3) performed a quantitative comparison between the proposed INS/GNSS integration and raw dual-satellite LGNS measurements.