A New Integration Method for MEMS Based GNSS/INS Multi-sensor Systems

Trimble has developed its new multi-sensor GNSS-INS integrated system which is called BD935-INS. It employs the new Quasi-tightly-coupled (QTC) integration architecture [1-3] and Trimble’s centimeter-accuracy GNSS positioning technology to produce an accurate, robust and low-cost single-board integrated product for small and medium sized unmanned aerial vehicles (UAV), ground based and marine platforms. The new system has the salient characteristics of a tightly-coupled integration with a much simplified design. It features INS seeding of the GNSS RTK engine to increase the availability and accuracy of RTK output in challenging GNSS signal environments. In addition an observable subspace constraint (OSC) is applied in the INS-GNSS position measurement to block the uncorrected a priori INS errors for entering the integration Kalman filter (KF). The new system has been extensively tested. Field test results from land-based mapping vehicle missions in urban areas verify the benefits of QTC integration architecture. For UAV missions, it satisfies the high accuracy demands for position and orientation as well.