Precise Positioning for Industry

Positioning makes use of ultra-wideband (UWB) radio technology. Because this is based on short-duration pulses, it can achieve a very high time resolution. This in turn makes the system very robust against the effects of multipath propagation and ensures very high accuracy of the measured positions. Meanwhile, its large radio frequency bandwidth and simultaneously low signal power levels mean it does not disturb the spectrum and can coexist with other radio systems. Carrierless transmission simplifies the hardware design of UWB systems.

Different measuring principles are applied:

Round trip time (RTT):

This method calculates the location based on the time it takes for the signal to travel from the transmitter to the receiver and back again. This method is simple and delivers high accuracy.

Uplink time difference of arrival (TDoA):

TDoA supports a higher number of participants than RTT. This method uses triangulation to determine locations. The object to be located acts here as a transmitter to the pre-installed base stations, which are synchronized beforehand. Compared to Downlink TDoA, the number of objects to be located is limited by high utilization of the radio channel.

Downlink time difference of arrival (TDoA):

In contrast to uplink TDoA, here the base stations transmit to the objects to be located. This makes efficient use of the radio channel, as only a few base stations transmit a signal. As a result, any number of objects can be located with an average accuracy of a few centimeters.

The Roundview system scans the angle of the signal and its distance. Vehicles fitted with Roundview can detect an object equipped with a tag anywhere in the room. Several strings of antennas attached to the vehicle scan the surroundings. They detect the tag and its distance and direction from the vehicle at any point, allowing the vehicle to follow the tag.

Adhoc is a self-calibrating UWB positioning system. Rather than having to be laboriously calibrated, anchors determine their position themselves. This permits the use of mobile anchors. Messages are sent to nodes that are not within range. The nodes are easy to configure. This communication concept is implemented on the Wismit platform, meaning the system is quick to set up and does not require any complex infrastructure. This makes it particularly suitable for dynamic applications such as construction sites.

The Wismit platform is hardware used in the rapid evaluation of positioning, communication and identification technologies. It can also serve as a basis for customer-specific developments in various areas. This platform enables the simultaneous use of different positioning technologies.

It comprises different communication components, such as positioning and communication chipsets with different frequency ranges (868 MHz, 2.4 GHz, 3.25–4.75 GHz or 4–6.5 GHz) and integrates different sensors (such as accelerometer or gyroscope), microcontrollers, and RFID or NFC. The credit card sized all-in-one platform has an interface to Raspberry Pi from version 4.4 onward and an inductive charging battery (Qi standard).