## 8 Conclusions  
The present paper has presented a novel framework for indoor AR navigation that overcomes two key challenges: operating within wide, absolute coordinate spaces and minimizing cumulative positioning errors in camera-based spatial tracking. This framework utilizes high-accuracy spatial tracking enabled by the VIO of contemporary smartphones, which is enhanced by the integration of location reference image markers and a local-toglobal spatial coordinate transformation, hence ensuring precise positioning within a global coordinate context. A strategy of periodic image-based calibration has been introduced, with designed user interactions guiding the calibration markers, significantly reducing the impact of accumulated errors and improving navigation accuracy over extended distances. This approach was implemented in an indoor AR navigation system deployed at the Mineral Industry Museum of Akita University, where demonstration experiments validated its effectiveness.  
Our work stands apart from the current academic literature as a pioneering systematic framework for indoor AR navigation design. The key strengths include the ability to extend high-accuracy local positioning to larger areas, the innovative calibration method to minimize accumulated errors, and its practical application in an existing indoor setting. Although reliance on VIO and periodic calibration could be considered limitations, they offer opportunities for further research in usability and accuracy enhancements.  
Future research will focus on usability experiments and user studies using an improved prototype with a more sophisticated user interface. We aim to refine our framework by exploring different geofence settings for practical spatial design and investigating solutions to improve indoor LBS usability and functionality. By comparing various settings and exploring new technologies, we can extract principles that will guide the development of practical and high-quality AR navigation applications and services, further contributing to the field of indoor AR navigation.  
Conceptualization, M.L., M.A., K.O., T.U. and R.S.; data curation, M.L., K.O., K.I. and Y.J.; formal analysis, M.L., M.A. and K.O.; funding acquisition, M.A. and M.L.; investigation, M.L., M.A., K.O., K.I. and Y.J.; methodology, M.L., M.A. and K.O.; project administration, M.L., M.A., T.U. and R.S.; resources, M.L., M.A. and T.U.; software, M.L., M.A., K.O., K.I. and Y.J.; supervision, M.L. and M.A.; validation, M.L. and M.A.; visualization, M.L., K.O., K.I. and Y.J.; writing--original draft, M.L.; writing--review and editing, M.L., M.A., T.U. and R.S. All authors have read and agreed to the published version of the manuscript.  
This research was funded by JSPS Grant-in-Aid, grant numbers JP23K11362, JP24K15631, JP22H00764, and JP19H04120.  
Not applicable.  
The data presented in this study are available on request from the corresponding author. The data related to the Mining Museum's property, including the floor plans and photos of the signboards and exhibits, will not be available without the museum's permission.  
We deeply appreciate [PERSON] and [PERSON] for their great contributions to our research on constructing a framework for indoor AR navigation. We further thank the Mineral Industry Museum, Akita University, for providing the field for the service experiments.  
[PERSON] is employed by the Shimizu Corporation. The authors declare no conflicts of interest.