WLAN-based Indoor Navigation. What are the new technical possibilities?

Term Paper, 2014

11 Pages

Valentina Barysava (Author)



1 Introduction
1.1 Motivation
1.2 Aim of the work
1.3 Delimitation of the topic

2 Definition of important terms

3 Current state of practice
3.1 Sensor-supported WLAN-based technology
3.2 The fields of application

4 Conclusion

5 References


When entering an unknown building, the problem arises that the visitor has to orientate himself in this building and find the desired destination by the quickest way. This is possible by locating and navigating with a mobile device and can thus be solved.

In this term paper we go into the topic of indoor navigation in more detail and introduce one of the most important localization and navigation systems. This technology uses fingerprint positioning via WLAN.

WLAN-based indoor navigation

Author: Valentina Barysava, Ostfalia University of Applied Sciences, Degree Course Commerce and Logistics, the 6th semester

1 Introduction

1.1 Motivation

Due to the rapid development of mobile devices, especially with regard to their performance, the possibilities of navigation with these devices are increasing. Especially in the area of indoor navigation there is still a lot of potential. The problem is that the GPS signal is not available inside buildings and therefore navigation is not possible with normal applications, as these no longer receive a signal from the satellites and thus the position of the mobile device can no longer be determined.1 For this problem, the technical variants of indoor navigation are used, which are explained in this paper. However, the possibilities of indoor navigation also have their problems. Many technologies have a high acquisition value, since the map material has to be made available first and usually has to be digitized first. In many areas, the technology must first be retrofitted in order to really achieve the desired performance. The accuracy of the position determination also plays a role, so it is important that the technology can guarantee high accuracy when it comes to calculating the position.2

The topic is of particular relevance to us because these technologies have great potential and enable seamless navigation that takes place inside buildings. Especially the multitude of possibilities makes the topic very interesting and it is important to find out which of these technical possibilities is really suitable for use and will be so interesting for the user.

The work is intended to give the reader an overview of WLAN-based indoor navigation. In addition, it is shown that such navigation is already possible within buildings and it also shows which obstacles still exist.3

1.2 Aim of the work

The priority at work is to study WLAN-based indoor navigation. It is to be clarified which technical possibilities exist in indoor navigation and how these can be improved in order to provide even more precise navigation in buildings. It will be shown what is possible with the current state of the art.

1.3 Delimitation of the topic

This topic deals exclusively with possibility that is limited to indoor navigation and is so accurate from the position determination that an exact navigation is possible. Passive possibilities, such as navigation with RFID chips, are also left out, as these technologies have too high acquisition costs.

We will go into WLAN-supported navigation to be more precise with fingerprint technology, as it has low acquisition costs compared to other possibilities. WLAN is also widely used, especially in shopping centres and airports, and thus provides a high density of signaling devices for precise location determination.

2 Definition of important terms

- Indoor navigation is used to determine the location within buildings where no GPS signal is available. Determining one's position means determining one's own position. This location is used for the rest of the navigation process and is an important component, therefore it is updated at regular intervals to allow accurate navigation.4
- The fingerprinting method used for WLAN localization serves to determine the position of the user and his mobile device. Fingerprints of the signal strength of the received WLAN router, here the BSSI values, are stored in a database. These are called up later during navigation and the location can be determined on the basis of the different signal strengths. This method is called fingerprint because each constellation of the different signal states like a fingerprint is only present once.5
- Gyroscope sensors and acceleration sensors in a smartphone are used to calculate the acceleration and orientation of the mobile phone user. The gyroscope sensors measure the rotation of the mobile phone with the aid of gravity in order to detect acceleration, rotation and changes in position. The results are used for further calculations in the navigation process.6

The algorithms in this thesis serve to calculate the shortest path. The nature of man is that he always wants to take the shortest route and does not like to take detours. The calculation of the path success in most cases according to the algorithm of Dijksta, as this always calculates the most optimal route.7

3 Current state of practice

In the following, we will first describe the technology that is being put into practice today, how it works, what it enables. Their areas of application are then briefly explained. It describes how navigation inside buildings works with the help of sensor-based WLAN-based technology and what processes take place in this navigation to navigate the person to their desired destination.

3.1 Sensor-supported WLAN-based technology

In practice, sensor-supported WLAN-based technology is used for indoor navigation. To realize indoor navigation, you need a very simple system infrastructure. First, in the building in which you want to navigate, the underlying network of WLAN access points is essential. The identifier of each transmitting station is called Basic Service Set Identifier (BSSID).8 Second, you need a mobile device that can be a smartphone like the iPhone. Each mobile device has sensors that perform a supporting function to achieve a better position determination. Navigation also requires a digital map or building plan, which is available to the user on the mobile device or on the external server at any time.9 Thirdly, one needs an external server, it takes over the calculation of the measured data, it also contains the reference database and previously created fingerprint database. The fingerprint database contains reference data for the fingerprint method, i.e. signal strength values of the surrounding WLAN networks depending on the position of the mobile device.10

To begin navigation, the user must download the appropriate application and install the program. When entering the building, the user is asked whether he wants to start navigation. The user does not know which processes work in the background after pressing the Start button, he only sees the graphic interface of the mobile device. During this time, the sensors measure its speed of movement, try to determine where it is moving and determine its orientation direction. The gyroscope and compass data allow a correct calculation of the alignment, gyroscope and acceleration sensor determine the relative acceleration. This data is stored on the mobile device.11

At the same time, the fingerprint procedure is carried out. The signal strengths of the surrounding WLAN networks are measured and first formatted together with their identification on the mobile device and then stored.12 A fingerprint is created on the basis of this measurement data. The fingerprint contains the identification of each transmitting station and its measured signal strength value, which is negative, between -10 and -96, where -10 represents the strongest reception and -96 the weakest. The combination of different BSSIDs and their signal strengths is usually unique, like a fingerprint, therefore the procedure is called so. If you change the position of the mobile device, the signal strength values of these networks also change.13 After creating a fingerprint, the current measurement data is sent to the server and compared with the data from the fingerprint database. The server returns the match values in the form of a location ID. However, the location ID cannot be linked to a specific location, since the final link takes place on the mobile device. This is done for reasons of data protection, so you cannot see at a central point where every user is at any time.14 After the adjustment of the location acceptance, which was determined by sensors, with the result from the fingerprint procedure, the user is indicated his whereabouts on the mobile device.15

After determining the position, the user can enter his destination. The application is permanently connected to the server where it transmits the request and calculates the route using various algorithms and their combinations. After analyzing people's movement patterns, as explained in the basics, they want to reach their destination as quickly as possible, so they usually choose the shortest route. Therefore, this paper describes the most commonly used algorithms that calculate the shortest path. This is the Dijkstra algorithm.16 It calculates the shortest path from a starting point to all other points in a coherent and weighted graph. Floyd's algorithm also calculates the shortest path but compared to Dijkstra's from all points to all other points, so if you change the position, the shortest path is automatically recalculated.17 The A* algorithm does not always show the optimal path, but it is faster in the calculation because a heuristic is used to reduce the actual calculations.18 After the calculation, the user is shown the route on the display. The user is guided to the desired location.

The solutions Sensor Fusion for indoor navigation offers a variety of combinations of different technologies these combinations allow the following advantages:19

1. More accurate positioning. Experience has shown that indoor navigation is faulty solely due to sensor data or WLAN technology. But if you use a combination of both methods, you get a much more accurate result.20
2. Third-party suppliers can fall back on the indoor location. For example, retailers can send advertising or information about their own products and companies to customers in the immediate vicinity.21
3. Indoor navigation with lower costs. The system infrastructure, which only consists of an external server and a mobile device, as well as a building plan, is more cost-effective compared to the other technologies.22
4. Better results even with few reference data. For the implementation of the fingerprint procedure, it is necessary to have a lot of reference data available, because with each step of the user the position of his mobile device changes, and as a result the signal strengths of the surrounding WLAN networks also change. If the reference data is missing, this can lead to incorrect position assumptions.23 Here the additional sensor data of the Smartphone helps.
5. Less battery consumption, memory capacity, shorter computing time. Due to many calculations and measurements, the accumulator of the smartphone is heavily loaded, one needs more power from the mobile device. In order to relieve the mobile device and shorten the computing time, all complicated calculations are carried out on the external server, which requires a fast WLAN network.24

Indoor navigation based on WLAN technology has the advantage that nowadays any mobile device can carry out a navigation and thus determine the exact location. Especially the combination of the WLAN technology with the different sensors of the mobile device allows an even more accurate position determination, but also the battery is spared and you can navigate longer.

3.2 The fields of application

The above solution for indoor navigation is used in various areas today. In July 2013, Kaiser's became the first German retailer to offer its customers indoor navigation in its supermarket in Berlin. The buyers have the possibility to be guided from their iPhone to the desired product or to work through an entire shopping list in a route-optimized way. Although not always the optimal way is indicated, because the interests of the dealers do not always coincide with the interests of the customer. If, for example, the retailer wants your route not to pass by the promotional goods or, conversely, you are to be guided through certain routes in the shopping centre, he can discuss this with the provider who programs the algorithms accordingly.25

Indoor navigation is of great importance in buildings where orientation is too complicated for people. As is the case in airports, for example, the buildings are too confusing, so that passengers are afraid of not finding the right gate or missing their departure due to the short time available, which restricts their movements in the building. With the help of indoor navigation, customer satisfaction is increased and punctual boarding is guaranteed. The other aspects are an increase in sales and the strengthening of customer loyalty. Indoor navigation is used for marketing/couponing. Navigation in buildings allows access by third parties, who can advertise the most attractive offers in a site-specific manner via push messages or navigation fade-ins, because airports generate up to 50% of their sales via shops and restaurants. The data is also used for analysis. Even anonymous data such as where passengers are, where the largest crowds are, can provide valuable information. This information is used for the optimization of operational processes, the identification of the optimal location for new business, for the optimization of walking and escape routes.26

In the museums, a mobile guidance system recognizes the position of visitors and shows them the surrounding exhibits. Visitors select the exhibits they are interested in and receive further information in the form of videos, photos and animations.27

Visiting the fair is also easy and effective thanks to the solutions for navigation in buildings. Via the application the visitor gets the complete exhibitor list of the fair, detailed information about the company and its products. The application can be customized, i.e. visitors can choose the companies they are really interested in and are guided to them by the shortest route. The companies also have their advantages in this way, they have an overview of their potential customers and can address them specifically, thus better presenting their contact details and product information.28


1 Cf. Obermaier, J. (2011), p. 2

2 Cf. Obermeier, J. (2011), p. 3

3 Cf. Gleim, D. (2012) P. 2

4 Cf. Oschatz, A. (2011), p. 6

5 Cf. Oschatz, A. (2011), p. 13 ; Cf. Teker, U. (2005), p. 91

6 Cf. DATACOM book publisher (2014)

7 Cf. Schwanengel, A. (2010), p. 45

8 Cf. Schelewsky, M.; Januschat, H.; Bock, B.; Stephan, K. (2014), p. 53; Dalhaus, M. (2006), p. 30

9 See Gleim, D. (2012) p. 17 / Köppe, E. (2014), p. 27-28

10 See Obermaier, J. (2011), p. 6 ; Meyer J. (2013), p. 83 ; Teker, U. (2005), p. 58

11 Cf. Werner, M. (2012), p. 19

12 Cf. Oschatz, A. (2011), p. 13 ; Cf. Teker, U. (2005), p. 91

13 See Schelewsky, M.; Januschat, H.; Bock, B.; Stephan, K. (2014), p. 54; LMU Munich

14 Cf. Gleim, D. (2012), p. 53

15 Cf. Bock , B.; Löwel, Th. ; Rosch, J.; Ritzer, J.; Lienkamp, M.; Twele, H.; Fall Carnet , D. (2014), p. 54

16 Cf. Schwanengel, A. (2010), p. 45

17 Cf. Kalbacher, M. (1996), p. 57

18 Cf. Plümer, L.; Schmittwilken, J.;. Kolbe, Th. H. (2004), p. 8

19 Cf. Gleim, D. (2012), p. 30

20 Cf. Gleim, D. (2012), p. 30

21 Cf. Schelewsky, M.; Januschat, H.; Bock, B.; Stephan, K. (2014), p. 59

22 Cf. Oschatz, A. (2011), p. 14

23 Cf. Gleim, D. (2012), p. 20-76

24 See Huber, Th. ; Kreuzer, J. ; Diemer, R. (2007), p. 73 ; Fuchs, Th. (2009) , p.134

25 Cf. Lebensmittelzeitung.net (2013) ; Tarin, W. (2013), p. 95

26 Cf. Schelewsky, M.; Januschat, H.; Bock, B.; Stephan, K. (2014), p. 54 ; Rhein-Neckar Newspaper (2014) ; Insoft TV Documentary

27 Cf. Fraunhofer IIS. awiloc (2012)

28 Cf. Fraunhofer IIS (2011) ; Insoft (2014)

Excerpt out of 11 pages


WLAN-based Indoor Navigation. What are the new technical possibilities?
University of Applied Sciences Braunschweig / Wolfenbüttel; Salzgitter
Catalog Number
ISBN (eBook)
Indoor navigation, WLAN-based, sensor-supported, location, fingerprint
Quote paper
Valentina Barysava (Author), 2014, WLAN-based Indoor Navigation. What are the new technical possibilities?, Munich, GRIN Verlag, https://www.grin.com/document/497993


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