Bluetooth RSSI, AOA and UWB, What is High Positioning Accuracy?

Bluetooth RSSI, Bluetooth AoA, and UWB are the mainstream indoor positioning methods at present, what are the advantages and disadvantages of these three positioning methods?

Bluetooth RSSI positioning calculates the position according to the relationship between signal strength and distance. Since the relationship between signal strength and distance is non-linear, and the signal strength is affected by many factors, it will be unstable (such as occlusion, different directions, different broadcast channels, etc.), Therefore, the positioning accuracy is not high. Bluetooth RSSI positioning is divided into two positioning methods, one is regional positioning, the other is triangular positioning. The method of Bluetooth beacon + Bluetooth gateway can realize regional positioning, and the method of Bluetooth beacon + Bluetooth work card + Bluetooth gateway can realize triangulation. It is forwarded to the Bluetooth gateway, and the Bluetooth gateway forwards the data to the server for location calculation.

Bluetooth AoA positioning requires a Bluetooth AoA base station (the base station has an array antenna). There will be a phase difference between the Bluetooth signals sent by the Bluetooth tag reaching different antennas. Using this phase difference, we can get the angle of the Bluetooth transmitter reaching the receiver.

UWB uses the flight time of the signal between the tag and the base station to calculate the distance. Since the distance and time have a linear relationship, distance = time * speed of light, so the positioning accuracy is high. UWB positioning is divided into two types: TWR and TDOA.

The following is a comparison of these four positions: