Relationship between Angle of Arrival Tracking and Bluetooth AOA Positioning

In the field of wireless positioning technology, Direction of Arrival (DOA) and Bluetooth AOA (angle of arrival positioning) technologies are closely related, and together they constitute the core technology system of high-precision indoor positioning. Angle of Arrival Tracking achieves target positioning by measuring the direction of signal arrival, while Bluetooth AOA positioning technology applies this principle to Bluetooth signals, achieving centimeter-level positioning accuracy through antenna array and algorithm optimization.

Homologous technical principles: Evolution from DOA to Bluetooth AOA

The angle of arrival tracking technology receives signals through antenna arrays and calculates the signal direction using the phase difference of signals arriving at different antennas. For example, in a radar system, the azimuth and elevation of the target can be calculated by analyzing the phase difference of the signals received by each antenna in the array. Bluetooth AOA positioning technology inherits this principle, combines the antenna array with the Bluetooth signal, receives the Bluetooth signal transmitted by the tag through the base station, and calculates the signal arrival angle. For example, in industrial scenarios, the base station receives the tag signal through a 3×3 or 4×4 antenna array, combines IQ sampling and phase difference calculation, and achieves sub-meter positioning accuracy.

 

Synergy of hardware architecture: Fusion of antenna array and Bluetooth chip

The core hardware of angle of arrival tracking technology is the antenna array, and its layout and size directly affect the positioning accuracy. For example, the uniform linear array (ULA) realizes azimuth measurement through linearly arranged antennas, while the uniform circular array (UCA) can measure azimuth and elevation at the same time. On this basis, Bluetooth AOA positioning technology integrates the antenna array into the Bluetooth base station and requires the tag device to achieve positioning with only a single antenna. For example, in a factory positioning system, the base station deploys a 4×4 antenna array, the tag device is powered by a button battery, and sends signals through the Bluetooth 5.1 protocol. After receiving the signal, the base station calculates the angle of arrival and combines the data of multiple base stations to achieve three-dimensional positioning.

 

Complementarity of algorithm optimization: from signal processing to positioning solution

Arrival angle tracking technology relies on complex signal processing algorithms, such as the MUSIC (multiple signal classification) algorithm, which separates the signal subspace and the noise subspace through eigenvalue decomposition to achieve high-resolution DOA estimation. On this basis, Bluetooth AOA positioning technology optimizes the algorithm for Bluetooth signal characteristics. For example, spatial smoothing technology is used to eliminate multipath interference, and the Kalman filter algorithm is used to correct position drift. In a certain warehousing and logistics scenario, the system calculates the initial arrival angle through the MUSIC algorithm, and then uses the Kalman filter to fuse multiple frames of data to reduce the positioning error from 0.5 meters to 0.3 meters.

 

Symbiosis of application scenarios: from industrial safety to consumer experience

Arrival angle tracking technology is widely used in radar, sonar and other fields, while Bluetooth AOA positioning technology focuses on indoor scenarios. For example, in factory safety monitoring, the Bluetooth AOA system monitors the location of personnel in real time through the electronic fence function, and triggers an alarm when a person enters a dangerous area. In consumer scenarios, this technology can realize shopping mall navigation and item search. For example, a shopping mall deploys a Bluetooth AOA base station, and customers receive signals through a mobile phone APP. The system combines the arrival angle data with the beacon location to realize store-level navigation services.

 

The relationship between arrival angle tracking and Bluetooth AOA positioning technology is essentially a combination of principle inheritance and scenario innovation. The former provides a theoretical basis and algorithm framework for the latter, while the latter promotes the popularization of high-precision positioning technology through Bluetooth ecology and hardware optimization. With the maturity of the Bluetooth 5.1 protocol and the reduction in the cost of antenna arrays, Bluetooth AOA positioning technology will play a greater role in areas such as Industry 4.0 and smart cities.