TIGHTLY-COUPLED RTK/INS INTEGRATED NAVIGATION USING A LOW-COST GNSS RECEIVER AND A MEMS IMU

Abstract. The Global Navigation Satellite System (GNSS) real-time kinematics (RTK) is a technology to provide centimeter-level navigation services in outdoor areas. GNSS/INS integration typical integrated system, including loosely, tightly, and ultra-tightly coupled integration, which has been studied for decades. Although GNSS aiding INS relatively mature RTK rarely used be with INS. In this work, we present model tightly-coupled (TC) scheme integrate using an extended Kalman Filter (EKF). Multi-GNSS multi-frequency double-differenced pseudo-ranges carrier phases are the updates of measurement model. To make ambiguity resolution, well-known LAMBDA algorithm search possible series, then use best integer equivariant (BIE) method decide on most likely ambiguities proper weighting strategy select from candidates. test performance proposed TC model, implemented two field vehicular tests low-cost module equipped Micro-Electro-Mechanical (MEMS) IMU. Using platform, our RTK/INS engine can achieve solutions under open sky conditions. harsh environments, system navigates scenarios mean errors 0.48 0.57 m, 51% 28% better than loosely-coupled system.