Integrated Navigation System with a Dual-Antenna GNSS Receiver and a MEMS IMU Embedded into One of the Two Antennas

The integrated navigation system for determining the position, velocity and attitude of a vehicle is described. This system consists of a dual-antenna GNSS receiver and a microelectromechanical inertial measurement unit embedded into one of two antennas. The dual-antenna GNSS receiver measures only two of the three attitude angles, which are calculated from the fractional parts of the total phases of the carrier signal without resolution of integer ambiguities. Inertial measurements are performed by the inertial measurement unit located inside one of the antennas near its phase center. The measurements are transmitted to the GNSS receiver via the radio frequency cable, together with the GNSS signal received by that antenna. Inertial measurements are combined with the GNSS measurements of the position, velocity, and two attitude angles using the Extended Kalman Filter according to the “loose coupling” approach. Operation principles of individual components of the integrated system are described. The results of the experiments with this system-carried out on various types of vehicles and under various environment conditions are presented.