Improvement of the Standard GNSS/IMU Solution for UAVs Using Already Existing Redundant Navigation Sensors

Navigation parameters like position, velocity, and attitude are essential for many UAV (Unmanned Aerial Vehicle) applications. Especially for automatic or autonomous UAV applications, the navigation parameters have to be very accurate and reliable. Currently, the reliability of all critical system components (like the communication or the navigation module) is improved by the redundancy concept. Therefore, the navigation module consists of at least two GNSS (Global Navigation Satellite System) antennas and receivers and two IMUs (Inertial Measurement Units). But these redundant sensors work completely in a separate way, so the redundancy is used only as backup in the case of sensor failures. This paper deals with the improvement of the accuracy and reliability of all navigation parameters by using the already existing redundant navigation sensors. A loosely-coupled extended Kalman filter integrates the positions of the two GNSS antennas with IMU and magnetometer measurements. Additionally, precise data (Precise Point Positioning) is added to improve the accuracy of the navigation solution, and the moving baseline between the redundant GNSS antennas is added to support the heading. This paper shows the total potential for the navigation solution by exploiting the already existing redundant navigation sensors.