Augmented Reality (AR) tracking for mobile devices is not realiable in environments where large virtual content, such as an entire virtual building, is to be displayed to the user. This paper presents a study on how multiple on-site markers can be used to better align the virtual scene to the real-world environment to improve large-scale AR experiences. The method consists of detecting QR markers from the video stream, and then updating the position, orientation, and scale of the virtual content in order to minimize the error between the real markers and their corresponding virtual markers. This allows for more accurate tracking and can be used in more complex environments. Three different evaluation methods are proposed. Additionally, experiments were conducted to explore the influence of marker density and marker layout. These experiments show that higher density layouts as well as structured layouts lead to higher accuracy and stability.