Home Blog A Comprehensive Guide to Bluetooth® 5.1 AoA Positioning Technology

A Comprehensive Guide to Bluetooth® 5.1 AoA Positioning Technology

Minew Jun 28, 2024

Industry Challenges

Bluetooth® 5.1 AoA Positioning

Many industry sectors face heavy demands and difficulties in location tracking and positioning. Traditional Global Positioning System (GPS) and Global Navigation Satellite System (GNSS) methods struggle with accuracy problems when it comes to indoor settings. The common sense is that GNSS and GPS technology cannot be used for indoor positioning because signals from the satellites will be blocked, absorbed, or scattered by the building complex (Lachapelle, 2004). Recognizing the limitations of GPS and GNSS in terms of indoor location tracking is where Bluetooth® AoA position technology come into people’s horizon for a high-precision and cost-effective alternative solution.

Understanding Bluetooth® 5.1 AoA Positioning Technology

The purpose of Bluetooth® Angle of Arrival (AoA) Positioning Technology is to determine the precise location of Bluetooth®-based items and electronic devices. By definition, it is a method of Bluetooth® Direction Finding that estimates, measures, and calculates the angle at which a Bluetooth® signal arrives at an array of antennas (Lee, 2023). On the one hand, from an academic perspective, it is a method for spatially locating Bluetooth® devices by leveraging the geometric properties of signal propagation. On the other, more from a more easily-understood industry perspective, it represents a significant advancement in real-time location systems (RTLS) by employing advanced Bluetooth® technology and communication protocols. In contrast to many other commonly known unaggressive location tracking and positioning technologies (e.g., Ultra-wideband), Bluetooth® positioning, including both AoA and AoD serves as an active localization system (Pirzada et al., 2013), where portable Bluetooth® connected devices (e.g., personal badges) transmit signals to the receivers.


Understanding things without referring to the context in which it was coined, invented, or developed may remain less sufficient. Thus, we decide to dive into the historical development of Bluetooth® AoA positioning and explore many other concepts associated.

Indoor Localization System Active System VS PassiveSystem

Source: https://www.sciencedirect.com/science/article/pii/S2212671613000644?ref=pdf_download&fr=RR-2&rr=89aa1b0b48ae408b

Historical Development of Bluetooth® AoA Positioning

Unlike GPS offering pinched location, Bluetooth® is more concerned with proximity estimation instead of exact location positioning (Indoor Positioning System, 2024). Early in 2016, Bluetooth® 5.0 brought significant improvements in range, speed, and broadcasting capacity. However, during that period, RSSI-based positioning is strongly confined to complex indoor environments due to weaknesses such as lack of reliability and accuracy.


In 2019, Bluetooth® Alliance Special Interest Group (SIG) launched and included Direction Finding functions as part of Bluetooth® 5.1’s plan (Enhancing Bluetooth® Location Services With Direction Finding | Bluetooth®® Technology Website, 2019). The release of Bluetooth® 5.1 marked a major milestone in its integration with two very innovative indoor positioning methods: AoA and AoD. While offering centimeter-level positioning, Bluetooth® 5.1 or Bluetooth® Low-energy (BLE) also brings extensive benefits such as low energy consumption and extended communication range (Lee, 2023).


From general proximity to high-precision and low-cost positioning services, Bluetooth® and Bluetooth® Low-energy offer more transformative potentials for indoor and active positioning solutions due to its unparalleled advantages, such as reliability, wireless connectivity, low latency, and high-speed data transmission. Later in 2021, Apple’s cutting-edge AirTag and Apple Find My network achieved a combination of Bluetooth® and UWB (Ultra-wideband) technologies, also sparking popularity and rising demand for Bluetooth®-based tracking technology.

Difference between Bluetooth® AoA and Bluetooth® AoD

Both Bluetooth® AoA and Bluetooth® Angle of Departure (AoD) belong to Bluetooth® Direction Finding. However, they are two very distinct methods, working in completely different and even opposite ways (Bluetooth® Direction Finding: A Technical Overview | Bluetooth®® Technology Website, 2023).

See the following charts: One major difference between Bluetooth® AoA and Bluetooth® AoD is the number of antennas placed and the direction of signals transmitted. In AoD mode, devices such as location beacons send a special signal via antenna arrays. As a comparison, Bluetooth® devices in AoA working mode, such as personnel tags and asset trackers only transmit a special direction finding signal using a single antenna while the receiving hub has many antennas. Multiple receiver antennas are placed next to each. As the special signal sent by the Bluetooth® Direction Finding devices is transmitted across the array, the receiving hub can detect relative distance and calculate direction changes (Hollander, 2023).

AoA Method and AoD Method

Source: https://www.bluetooth.com/blog/new-aoa-aod-bluetooth-capabilities/

Benefits of Bluetooth® AoA Positioning: Real-life Cases of Usage

According to Bluetooth® Alliance SIG, Bluetooth® location services and direction finding technologies are widely adopted in many industry sectors for their role in enhancing operational efficiency and indoor location tracking accuracy (Lee, 2023). Now, let’s zoom into the AoA positioning technique based on BLE & Bluetooth® 5.1, and understand its concrete benefits by referring to real-life application cases and scenarios.

Asset Tracking in Manufacturing and Warehousing

One of the most significant benefits offered by Bluetooth® AoA positioning is its ability to enhance asset tracking in terms of more efficient production unit and warehouse management. For example, a leading automotive manufacturer implements Bluetooth® AoA technology to monitor the location of critical tools and components on the assembly line. By deploying Bluetooth® beacons on assets and using AoA receivers throughout the facility, the manufacturer achieved real-time visibility into the location of every item. The system’s high accuracy minimized errors in inventory management, replaced the traditional labor-intensive time-to-time check, and thus improved the operational efficiency of the entire workforce.

Indoor Navigation in Proximity Marketing

In retail sectors, it is imperative for business managers and service marketing specialists to predict customer traffic and better correlate those numbers with store capacity. Bluetooth® AoA positioning is catering to this. The accurate indoor location tracking and positioning features powered by Bluetooth® AoA can help service and proximity marketers to send tailor-made discounts and promotions based on customers’ location, and even notifications about items they had previously viewed online. This level of personalization and convenience not only improved customer satisfaction but also increased sales conversion rates.

The Way Forward

There is no such thing as perfect technology. Bluetooth® AoA positioning is not an exception. It faces challenges and limitations, such as limited range, line-of-sight requirements, and a heavy data processing burden. Such disadvantages also open a new door to improvements and upgrades. By tapping into the future of Bluetooth® and IoT hardware innovation, we have already seen rapid advancements happening in the Bluetooth® domain. The integration of Bluetooth® AoA positioning with IoT platforms and artificial intelligence (AI) further enhances its capabilities. AI-driven analytics and machine learning algorithms improve positioning accuracy, predictive maintenance, and context-aware applications.

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