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Indoor navigation using WiFi as a positioning technology

Indoor navigation using WiFi as a positioning technology

Inside buildings WiFi is a good alternative to GPS, which is not available indoors. In most cases it is easy to install a WiFi positioning system (WPS), since WiFi access points already exist in many buildings. The advantage is that for example existing cash register systems, public hotspots and access points of shops or exhibitors can be used. The user doesn’t necessarily have to connect with the WiFi, it is sufficient to have WiFi enabled.

For positioning, the so-called fingerprinting method is used. The strength of the WiFi signals (received signal strength indication, RSSI) and the MAC address (media access control) are significant. There must be an appropriate app installed on the smartphone which calculates the current position based on these data. Later in this article you will learn about how these data are collected.

Accuracy of WiFi for indoor positioning

Accuracy depends on multiple factors, for example the number of available networks, reflections for example in corridors and last but not least shielding through walls, ceilings and your own body. The accuracy of WiFi used for indoor positioning varies from five to 15 meters – depending on the preconditions. Sensor fusion – this means the use of smartphone sensors – can even improve accuracy. A big advantage compared to GPS is that it is possible to determine the current floor level.

Setting up an indoor positioning system using WiFi

The calibration of position determination works with a one-time reference measurement in the run-up, where the signal strength of the WiFi networks is determined. For this purpose infsoft offers an app with which the client can easily execute the measurement on his own. This solution is client based, which means an app is necessary. Check out our developer portal and the SDK for more information and videos.

If a server based solution is more suitable for the project, infsoft’s self-developed locator nodes can be used. In this case no app is required, all WiFi capable devices are detected and WiFi tracking (asset tracking of, for example, mobile goods) is possible. Locator nodes also support Bluetooth low energy.

Pros and cons of indoor positioning using WiFi

Pros:

  • indoor positioning works without GPS
  • existing WiFi infrastructure can be used
  • enabled WiFi is sufficient
  • there is a back channel to the client
  • large range (up to 150m)
  • detects floor level

Cons:

  • relatively inaccurate (5-15m) compared to BLE/RFID
  • WiFi client based positioning is not possible with iOS devices – but BLE can be used as an alternative
  • application required

Application areas of an indoor positioning system using WiFi

Indoor navigation using WiFi makes sense when WiFi has to replace GPS in buildings. For example in complex infrastructures such as shopping malls, exhibition halls, railway stations, airports, hospitals, museums, office and industry buildings. An indoor navigation app improves visitor service and enables analyzing visitor flows. It is not suitable, if you have many iOS users among your audience.

Learn more about indoor positioning systems
Learn more about how infsoft uses WiFi as an indoor positioning technology

If you have any questions, don't hesitate to contact us.



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