Overview of WIFI, Bluetooth, Ultra-Wideband and RFID

There are four main technologies used in the industry. Each technology offers certain advantages and disadvantages. The differences are mainly visible in the accuracy and in the range. But also the power consumption and the tracking possibilities are different.

Indoor localization via Wifi

Positioning via Wifi offers a long range. The required hardware is also pretty and due to the existing know-how the installation is easy. However, wifi is only accurate to 15m, which makes it unusable for some applications.

An example of an application would be the determination of the areas in which workers are located in a factory building.

Indoor localization via BLE (Bluetooth Low Energy) Beacons

Bluetooth offers a similar use as wifi, only that it can reach about half the range with twice the accuracy. It is also extrem energy efficient and cost efficient. Analogous to wifi it is just as easy to install.

An example of an application would be the localization of containers in a big storage depot.

Indoor localization via Ultra-Wideband (UWB)

Ultra-Wideband has in comparison to wifi and BLE a very high accuracy, which goes down to 10cm. It also has a very high range and can therefore be used well for industrial applications where exact positioning is required. However, the technology had a relatively high purchase price compared to the other technologies in the past, but this has changed in recent years. With the lower price, ever more user-friendly and easy to install solutions are being developed.

An example of an use-case would be the localization and control of a logistics robot in a warehouse.

Indoor localization via RFID

RFID is a little different, as it is not an area-wide location, but a selective one. This means that RFID only checks whether there is a corresponding tag in the vicinity. The application thus separates itself more clearly from the other technologies.

An example of an application in practice is checking at which station a package is located in a package warehouse.

Functional principle of UWB

Ultra-Wideband is a type of short-range radio communication that can be used for indoor localization. In contrast to Bluetooth Low Energy and WLAN, the position determination is not based on the measurement of signal strengths, but on a transit time method (Time of Flight, ToF). The time of flight is measured between a tag and several anchors. For the exact localization of an object at least 3 receivers are necessary (trilateration).

This article should not go too much into the technical details. If you want to learn more about the physical principles of UWB technology, you can do so under this Wikipedia article.