Indoor Positioning with Ultra-wideband
Indoor tracking in industrial environments often requires very precise localization. For this purpose we offer solutions based on the short-range radio technology Ultra-wideband (UWB). It does not work with consumer standards such as WiFi and Bluetooth Low Energy, but offers an accuracy better than 30 cm.
Indoor positioning with Ultra-wideband has some significant advantages: The accuracy is 10-30 cm, which is considerably better than when working with beacons (1-3 meters) or WiFi (5-15 meters). Latency time is very low (position request up to 100 times/second). Height differences can be measured accurately. However, the technique is a special solution which requires appropriate components and thus is mostly suitable for special industry applications. Compared to WiFi or BLE, UWB is more cost-intensive when installed on the same area and cannot immediately display the position on a mobile device.
Functionality of Indoor Localization with Ultra-wideband
Ultra-wideband is a short-range radio technology which can be used for indoor positioning. In contrast to Bluetooth Low Energy and WiFi, positioning is done with transit time methodology (Time of Flight, ToF) instead of the measurement of signal strengths (Receive Signal Strength Indicator, RSSI). This method measures the running time of light between an object and several receivers (Anchors). For the exact localization of an object at least 3 receivers are necessary (trilateration).
The object or the person that should be tracked (asset) is equipped with a small tag (infsoft Locator Tag) which runs on battery power. It sends data (ID, ToF, timestamp) to so-called Anchors. They have a fixed position in the infrastructure and can use the running time of light to calculate the distance of the asset. Combining the data of 3 Anchors or more results in a positioning accuracy of 10-30 cm. The Anchors can be connected to the electrical grid or can be run on batteries. Their durability is at least 2 years and the range is 30-40 meters.
Setting up an Ultra-wideband Based System: Two Approaches
Visualization of positioning data in the backend, no display on a client (smartphone).
In order to localize assets, the infsoft Locator Tag measures the distance to several Anchors and sends the data back to the Anchors. infsoft Locator Nodes not only have integrated WiFi and BLE, but also a UWB module, which lets them act as a receiver (UWB receiver). The infsoft Locator Node processes the data it receives from the Anchors and sends them to the infsoft backend via WiFi, Ethernet or UMTS. Here, the position is displayed for example on a map.
Visualization of positioning data on a client (smartphone) and if necessary transmission to the backend.
If the positioning data should be immediately displayed on a mobile device (smartphone), the infsoft Locator Tags can communicate with the smartphone via Bluetooth directly. Time of Flight is measured, just like explained above, but there is no need for an infsoft Locator Node acting as an Ultra-wideband receiver/gateway. The Locator Node exchanges the data with the device via Bluetooth. The data can be sent to the backend from the device, if necessary.
Technical Features of Ultra-wideband
- Usage of extremely wide frequency bands with a bandwidth of at least 500 MHz
- Almost no interferences
- Frequency bandwidth 3,1 – 10,6 GHz
- Transmission power 0,5 mW / −41,3 dBm/MHz
- Reach 10-50 m (depends on the use case)
- Data rate 110 kbit/s – 6.8 mbit/s
UWB Anchor: UWB based anchors with fixed positions within the building. Calculates distances to tags in range and wirelessly shares the data within the Anchor network via UDP (User Datagram Protocol). Runs on batteries or can be connected to the electrical grid. Lifetime at least 2 years, reach 30-40 m, dimensions (LxWxH): 76 x 76 x 25mm.
infsoft Locator Node (Ultra-wideband receiver): The infsoft Locator Node works as a gateway and transmits the data from the anchors to the infsoft backend. Within server based installations, positioning happens there. More info on infsoft Locator Nodes.
infsoft Locator Tag: Transmitter based on UWB technology, which is attached to people or objects. It runs on batteries and transmits data for positioning to the Anchors. Dimensions (LxWxH): ca. 60 x 40 x 20mm. More info on infsoft Locator Tags.
Use Cases for Ultra-wideband Indoor Positioning
- Exact localization of forklifts including the determination of the vehicles’ orientation, for example when the sight is bad
- Analyzing itineraries, for example at a production line, subsequently runway optimization
- Asset tracking in industrial environments, for example localization of wares