Bluetooth AOA indoor Positioning System Solution

Bluetooth AOA positioning is a new type of indoor positioning technology, benefiting from the introduction of the Bluetooth 5.1 standard. The Bluetooth 5.1 standard introduces the AoA (Angle-of-Arrival) feature. The AOA positioning algorithm, also called Angle-of-Arrival (AOA), is a Bluetooth positioning algorithm based on the angle of arrival of Bluetooth signals. The advantages of the Bluetooth AOA positioning algorithm are that the positioning algorithm has low communication overhead and high positioning accuracy.

The direction of arrival of the signal from the transmitting node is sensed through the array antenna, the relative azimuth or angle between the receiving node (Bluetooth AOA positioning base station) and the transmitting node (Bluetooth AOA tag) is calculated, and then the unknown node is calculated by triangulation or other methods ( The location of the Bluetooth AOA label), as shown in the figure below.

Applicable scenarios: asset tag positioning, stadium personnel positioning, nursing home positioning system;

Monitoring technology: Bluetooth arrival angle positioning calculation;

Involving software and hardware: Bluetooth AOA positioning base station, Bluetooth AOA positioning card, Bluetooth AOA algorithm, etc.;

Positioning accuracy: 10cm~30cm;

Function realization: real-time positioning of personnel, a statistical roll call of construction personnel, electronic fence, one-key call for help, early warning of dangerous situations, etc.

Bluetooth AOA location base station and tag

The Bluetooth AOA positioning base station and tag are the basis of the Bluetooth AOA positioning system. The Bluetooth AOA positioning hardware products launched by Shenzhen Weineng Information Technology Co., Ltd. include the Bluetooth AOA positioning base station and the Bluetooth AOA positioning tag.

(1) Bluetooth AOA positioning base station

AOA positioning base station VDB2608, as the signal receiving end of Bluetooth AOA positioning system, is developed based on Nordic nRF52833 solution, external PA+LNA, using two-stage low insertion loss high-speed RF switch to realize fast scanning of the antenna array. The antenna architecture adopts a 12-antenna matrix antenna array, which can realize the solid angle positioning (elevation angle and azimuth angle) of a single AOA positioning base station.

The appearance of the AOA positioning base station VDB2608 is shown in the following figure.

VDB2608 cooperates with SKYLAB's（天工测控） self-developed Bluetooth AOA positioning system, and the positioning accuracy can reach 10cm-30cm (CEP90). The capacity of a single AOA base station (1 VDB2608) is 150pcs (with angle filtering). In terms of external interfaces, there are network ports and DC connectors, which support standard POE power supply or DC power supply.

AOA base station VDB2608 installation

AOA positioning base station VDB2608 adopts a snap-on structure design, which is convenient for ceiling installation. The installation is shown in the Bluetooth box mark in the following figure.

Bluetooth AOA positioning base station VDB2608 deployment

The actual deployment of the Bluetooth AOA positioning base station VDB2608 is shown in the figure below. It can be installed on a normal ceiling. It is recommended to deploy 4 AOA positioning base stations in each positioning scene area (there is no wall in the scene).

Installation height and spacing requirements: 3m<A, B<10m; 3m<H<5m.

(2) Bluetooth AOA positioning tag

Here we take the AOA positioning card as an example. SKYLAB's Bluetooth AOA positioning card also uses the nRF52833 solution as the signal transmitter of the Bluetooth AOA positioning system. It supports motion detection, supports SOS buttons and LED light display, and supports magnetic charging. The battery capacity is 550mAh. Under the default parameter configuration, the standby time is more than 1 month. The shell adopts the ultrasonic pressing method, which can achieve IP67 waterproof and dustproof performance. The appearance of the AOA positioning work card is shown in the following figure.

3. Bluetooth AOA positioning system

Four Bluetooth AOA positioning base stations are installed in each positioning area to collect the angle information of the AOA positioning tag (work card), connect to the back-end positioning server through a standard POE switch, and finally display the actual position of the AOA positioning tag on the PC side. The hardware architecture of the Bluetooth AOA positioning system is shown in the figure below.

4. Software Architecture of Bluetooth AOA Positioning System

SKYLAB's Bluetooth AOA positioning system architecture is divided into four layers, namely the object layer, acquisition layer, processing layer, and presentation layer, as shown in the following figure.

◆ Object Layer
The object layer includes people, objects, places, and things, that is, the people and objects under supervision. The real-time location can be obtained by locating the AOA positioning tag. If the alarm is alarmed, the video can be linked.

◆ Acquisition layer
The AOA positioning badge of the acquisition layer can be worn on the personnel. The Bluetooth AOA positioning card is the front end of data collection. As a wireless data transmission module, it can send positioning data regularly; AOA positioning base station, sensing equipment, network equipment, etc. are responsible for uploading the information data of the AOA positioning card in real-time to the processing layer for position calculation, data analysis, etc.

◆ Processing layer
The processing layer includes the Bluetooth AOA positioning engine server, data server, and business server. The server is responsible for location calculation, data analysis, and data auditing.

◆ Display layer
People wear AOA Bluetooth positioning tags (such as AOA positioning badges) to move within the coverage of AOA base stations and can view the current real-time positions of people and items through the display terminal. The initialization of system positioning data, business process management, user management, data query, etc. are all implemented through the browser.

5. Bluetooth AOA positioning software management system

The following is a demo of the Bluetooth AOA positioning software management system developed by SKYLAB. Through this positioning management system demo, you can query the real-time location of the person wearing the Bluetooth AOA tag, AOA positioning base station management, AOA tag management, personnel management, account management, and other functions.

(1)AOA positioning system login interface, as shown below:

(2)View the real-time position of the person wearing the AOA positioning tag on the software side, as shown in the following figure:

(3)AOA Bluetooth positioning tag management in the positioning area, as shown in the figure below:

(4)Bluetooth AOA positioning base station management in the positioning area, as shown in the figure below:

(5)In the software management system, the personnel who need to be located can be managed, as shown in the following figure:

(6)Map management, in the system settings - map management function, you can import maps of multiple positioning areas, and support the import of CAD/GIS indoor maps, as shown in the following figure.

(7) In Account management, you can set various operations such as account and password modification in the user center, as shown in the following figure.