Bluetooth Angle of Arrival, What Is It? How to Implement an BLE AoA Solution?

Since Bluetooth 5.1 Core Specification, the Bluetooth Angle of Arrival (AoA) technology has been included in Bluetooth Low Energy (BLE) for the purpose of Bluetooth Radio Direction Finding. When compared to traditionally received signal strength indication (RSSI), it is meant to boost location accuracy.

What is Bluetooth Angle of Arrival

The item is used to identify the direction in the Bluetooth angle of arrival (AoA) approach, such as a BLE tag in an RTLS solution, which broadcasts a specific direction-finding signal using a single antenna. The receiving device has a number of antennae grouped in an array, like an AoA locator in that same RTLS solution.

With BLE AoA technology, it is easy to reach sub-meter(0.3-1m) and high-precision positioning. This technology is widely used in smart retail, hospital personnel, asset tracking, warehouse and manufacturing factory process optimization, and so on.

1. a BLE AoA locator

2. multiple BLE tags

3. a PC computer

Deploy A Single AoA Locator to Send Data Directly to the Cloud

A single AoA locator can only output I/Q data when it is deployed, which includes the orientation angle and pitch angle of the corresponding tag. This information is each BLE AoA position locator's primary output data. The data is directly transmitted to the positioning engine's cloud platform.

A single locator can compute and get a distinct spatial absolute coordinate based on the identified tag height. Coverage depends on your installation height, Angle α maximum value: Height =h, α= 60℃, Coverage r= h*tagα ≈2h.

This option is suitable for those who use their own positioning algorithm or run the positioning algorithm on their own platform. They only need AoA locators to send the I/Q data straight to the platform of their businesses.

Deploy Multiple AoA Locators to Extend the Range of Positioning Space

A broader positioning coverage space is obtained by strapping down multiple AoA gateways, and the global spatial accuracy level is raised by multiple anchor course angle calculations.

There are two ways to meet your accurate positioning demands. The first is a positioning algorithm that runs on a cloud platform (as we mentioned before), while the second is a positioning algorithm that runs on a Bluetooth gateway with edge computing capabilities.

Use the edge gateway solution to output x, y, and z coordinates to your application platform if you only need to integrate them into your map application. The edge computing gateway functions as a local server that receives I/Q data from other locators and determines the coordinates of X, Y, and Z. 5 AoA locators can be supported by one Edge computing Gateway.

After knowing what is BLE AoA technology and its deployment modes, you can start to implment it.

1. Choose a good location on the ceiling, check the network cable and power supply port locations, and then place positioning stickers. Operators must be mindful of their own personal safety when implementing.
2. Drill holes in the locations indicated on the positioning sticker by using an appropriate electric drill bit based on the size of the plastic expansion tube.
3. Put the clear expansion tube into the gap created in step 2 of the process. The wall and expansion tube must both be level.
4. Align the top holder's fixing hole with the enlarged plastic tube and secure it using expansion screws one at a time. The top bracket is then securely fastened to the wall. Remember that network and power supply cables can be fastened to the bracket first through the wire hole, allowing them to be gathered in the bracket. Directly attach the ceiling bracket if necessary.
5. Sequentially install the locator ontology interface and insert relevant components.
6. Ontology-specific grooves, followed by lifting the ontology vertically and horizontally close to the suction top bracket while positioning the post in the relevant slot.
7. Slightly reposition the ontology so that the three bracket hooks can fit into their proper ontology positions. The bracket and ontology are now flush. Rotate in the direction of ontology's shear head. The AoA locator installation is finished when you hear a sound.
8. The final stage is to carefully inspect the product to ensure that it has been placed correctly, that everything is smooth, that there are no evident shaking issues, to clear the cable and power cable, and to hide as much as possible because one cannot simply become nude.

The complete installation steps and sketch map can be found here:

https://www.dusuniot.com/resources/development-instruction/aoa-locator-implementation/ 

1. Enter the genuine IP address of the gateway from the router to log in. The AOA locating gateway's general status was then provided to us.
2. Go to IOT Services -> Locator in the setup page. The gateway itself serves as the default MQTT server for posting data, and the server address and port credentials are changeable.
3. Install the MQTT Explorer by downloading it. Enter the gateway's IP address and port in the MQTT Explorer.
4. When you click "CONNECT" and turn on the AOA tag that was placed close to the locator, the position information will appear like the image I uploaded.

Reminder: this is the way to configure a single AoA locator. If you want to configure multiple AoA locators, feel free to contact Dusun IoT.

Real-Time Locating library (RTL lib) from Silicon Labs processes IQ samples obtained from the Bluetooth stack, employs multipath detection, and calculates azimuth and elevation before making the data available to the application via an open API.

If the library is aware of the positions of each locator, it may also use triangulation in a multi-locator scenario where many locators are receiving CTEs from the same asset tag to estimate the location of a tracked object.

In this instance, the estimated location is the output, while the locators' positions and estimated angles (AoA) are the inputs. The user's application determines how to handle the data after the positions are estimated. The graphic I submitted depicts the general architecture of an RTLS utilizing the Silicon Labs RTL library.