This in turn makes it easier for developers to implement location service applications.įor example, the AoA method is suitable for tracking a transmitting BLE transceiver.
#TDK BLUETOOTH STACK UPDATE#
Bluetooth 5.1 makes it easier for developers to take advantage of RF direction finding by including an update to the Core Specification to make it easier to extract “IQ” signal data (in-phase and quadrature-phase information) from BLE packets. The decision to include a direction-finding feature in Bluetooth 5.1 was made, in part, because of the influence of some enterprising companies that already offer proprietary AoA and AoD solutions for Bluetooth low energy (BLE) products. In each case, it is the receiving device that requires the computational power to calculate the direction of the transmitter. With the AoD method (right), beacons transmit AoD information while a mobile device receives (RX) the beacon signals and calculates position. With AoA, a receiving device tracks arrival angles for individual objects, while with AoD the receiving device calculates its own position in space using angles from multiple beacons and their positions (Figure 1).įigure 1: In the AoA method of direction finding (left), assets broadcast (TX) their location to an AoA locator which measures the signal's arrival angle. With the release of the Bluetooth 5.1 specification, the Bluetooth Special Interest Group (SIG) elected to support a third direction finding technique based on AoA and AoD. Positional accuracy for ToA systems can approach 1 m. Again, this method requires only one antenna per device, but the downside is the requirement that each device carry a highly accurate synchronized clock.
The downside is a lack of precision, with the technique offering an accuracy of 3 to 5 meters (m).Ī second common direction-finding technique is known as Time of Arrival (ToA), which is the travel time of a radio signal from a single transmitter to a remote single receiver. A key advantage of RSSI is that it requires only one antenna per device-eliminating the complexity, cost, and size of antenna arrays. Greater accuracy can be achieved by making multiple distance measurements from different points. Radio frequency (RF) direction finding based on RSSI provides distance approximation based on signal strength.
It then introduces viable platforms upon which to implement Direction Finding applications. This article, the first of two parts, describes AoA and AoD and explains how the enhancements to the Bluetooth Core Specification make it easier to implement the techniques. Specifically, the latest version of the Bluetooth Core Specification (v5.1) (marketed as “Bluetooth 5.1 Direction Finding”) has added Angle of Arrival (AoA) and Angle of Departure (AoD) direction finding features that make it much easier for developers to accurately determine the position of a Bluetooth transmitter in two or three dimensions. However, an update to the Bluetooth specification offers a more precise path forward. While Bluetooth’s received signal strength indicator (RSSI) can be used to estimate distance from a known fixed point, this technique is often not precise enough for applications such as an indoor positioning system (IPS) and asset tracking. The demand for location services is growing as logistics companies look to improve supply chain efficiency by tracking assets in real time, and businesses target productivity enhancements by monitoring staff and customer movements.
#TDK BLUETOOTH STACK HOW TO#
Part 2 shows how Bluetooth 5.1 Direction Finding-based applications can be developed and describes how to get started on these platforms. It then introduces suitable platforms upon which to run the new features.
#TDK BLUETOOTH STACK SERIES#
Editor’s Note: Part 1 of this two-part series describes the capabilities of Bluetooth 5.1 Direction Finding, an addition to the Bluetooth low energy firmware that enables designers to develop Angle of Arrival (AoA) and Angle of Departure (AoD)-based location applications such as asset tracking and indoor positioning systems (IPS).