Data fusion algorithm of Baro/GPS based on delta-altitude

As we all know, GPS cannot totally meet the need of safety-of-life applications in civilian aviation especially the vertical accuracy and integrity. It is widely accepted that integrating GPS with barometric altimeter (Baro) can improve geometry and consequently provide performance enhancement especially in the vertical direction. This paper presents a novel data fusion algorithm of Baro and GPS based on delta-altitude. This algorithm removes some of the conservatism built into the prior positioning algorithm of Baro/GPS integrated system. This paper focuses on analysis of accuracy and integrity performance of Baro/GPS integrated system. The results of simulation show that this algorithm can substantially improves navigation accuracy performance of the integrated system, especially in the vertical direction. Meanwhile, it indicates that great enhancement is achieved in integrity performance.