Altitude data fusion algorithm based on INS and GNSS and barometer

Abstract

An altitude data fusion algorithm is introduced based on inertial measurement system and global navigation satellite system and barometer, using Kalman filter. In order to reduce the principle error, temperature error, temperature gradient error and wind disturbance error, the altitude measurement data of barometric altimeter is compensated. In addition, the initial altitude data of the barometer is calibrated by using the altitude data of the global navigation satellite system measured at the start of the system. Then, according to the flight status of the aircraft and the validity of the global navigation satellite system, a fusion weight value is dynamically assigned, and a preliminary fusion is performed by using the altitude data from barometer and the altitude data form the global navigation satellite system. Finally, the altitude data after the preliminary fusion and the height data measured by inertial navigation system are fused by Kalman filter. The test results show that the accuracy of the altitude is less than 5 meters, which verifies the effectiveness and accuracy of the fusion algorithm. When the signal of the global navigation satellite system is lost, the measurement accuracy is only slightly reduced, but it is still close to the actual trajectory. And the system can track and recover quickly after the signal of the global navigation satellite system is recovered, which shows good fault tolerance.