# L5 IN: Overview of an Indoor Navigation Pilot Project
## 4 Conclusions  
An overview of the research of the L5 IN project was given herein, describing the individual work packages and discussing the relationships between them. The aim of the L5 IN project is to develop an autonomous application for indoor navigation. The workflow starts with a survey of the building and the processing of existing building plans. The geometrical, topological, and semantic data are merged into a BIM. Using this map as a basis, as well as 5G technology and smartphone sensors, positioning is carried out. The map is also used for visualization in a smartphone app. All these data are stored in a database and transmitted via the 5G network. The 5G network will be implemented in a campus solution on the premises of HafenCity University Hamburg as a prototype environment. With this holistic solution approach, it shall be shown that based on 5G technology, pedestrian indoor navigation with a standard deviation of 2-3 m and a confidence interval of 68% is possible. 5G makes indoor positioning possible anywhere and at any time, and it also plays an important role for any other positioning task. 5G positioning methods in combination with IMU sand GNSS solutions can improve the connectivity between indoor and outdoor environments. It is considered to be an infrastructure-based system, because 5G will be available to the vast majority of the population--as is planned for 2027 in the U.K., for example--while at the same time offering the possibility of providing 95% of the population with gigabit-capable networks by 2025 [41]. This amount of popularity and dependency between smartphones and 5G signal will solve the challenges that exist in typical infrastructure-based systems. Smartphone positioning is the result of sensor fusion, 5G network signal, and plan information. Each of these elements can work more accurately using a BIM. In sensor  
Figure 8: Extract of the XML schema showing the relationship between IfcSpaces. fusion, a geomagnetic field map can be used to evaluate the 5G signal quality based on material properties. Moreover, 5G and BIM work in both data transformation and visualization tasks to enable standardization of indoor navigation. Therefore, real-time 3D navigation will be the next result of combining BIM and 5G. Positioning is envisioned as an important element of 5G mobile networks. However, infrastructure-based methods are detrimentally affected by various factors, such as multi-path propagation and non-line-of-sight propagation (NLOS) reception. To deal with the negative influences, environmental conditions modeled in the BIM can be adopted. The BIM uses available sources such as building plans, images, and point clouds. Different data acquisition techniques will be discussed in future works. In this way, 5G positioning methods will be tested and developed within the 5G campus network. Meanwhile, positioning is supported by sensor-based and data-driven approaches, i.e., a realistic database can be established within the LSIN project. A mobile application will be developed for both the IOS and Android platforms with an open-source license, offering a standardized form of indoor navigation. The application will guide the user with different options, such as using stairs or escalators. Both 2D and 3D visualization will be available to support users to navigate themselves using the L5 IN app. Ultimately, a reliable prototype will be presented in order to take the field of indoor positioning one step further. Conceptualization, C.S., H.S. ([PERSON]), N.H. and H.S. ([PERSON]); methodology, C.S., H.S. ([PERSON]) and N.H.; formal analysis, C.S., H.S. ([PERSON]) and N.H.; data curation, C.S., H.S. ([PERSON]) and N.H.; writing--original draft preparation, C.S., H.S. ([PERSON]) and N.H; writing--review and editing, C.S., H.S. ([PERSON]) and N.H.; visualization, C.S., H.S. ([PERSON]) and N.H.; supervision, [PERSON] ([PERSON]); project administration, [PERSON] ([PERSON]); funding acquisition, [PERSON] ([PERSON]) All authors have read and agreed to the published version of the manuscript.