Research on barometric altimeter aiding GPS arithmetic in challenge environment

In the challenge environments such as urban canyon or high mountains, the positioning accuracy is often challenged when the number of GPS visible satellites is less than four or their constellation configuration is inadequate. Aids of other systems is necessary to improve the availability and integrity of the GPS in challenged environments. Therefore, barometric altimeter aiding GPS integration in land application is designed. An altitude assistant GPS positioning algorithm and its iteration formula is presented. Then, the contrast test is carried out. A high accuracy altitude is achieved by using a barometric altimeter, which compensates GPS position accuracy in the vertical direction. The vertical accuracy of the vehicle is well known in the cloverleaf junction using the integration system. The results show that the availability of the aided system is improved by more than 50% in challenge environment, and improved the positioning accuracy.