Ranging using the BLE AoA technology

Theme:

Localization/Signal Processing

Application:

Asset management/ Access Control

Contact Person:

Anastasia Lavrenko

External collabolator:

BouWatch Company

Intorduction:

BouWatch develops systems for securing construction sites. The core product are mobile camera masts that are placed at the site. The cameras are capable of detecting trespassing and producing an alarm that is sent to a control room for validation and follow-up. At such sites, a range of valuable manual tools is commonly in use. Equipping these tools with Bluetooth (BLE) beacons becomes increasingly popular. The recent 5.1 version of BLE allows locators to apply direction finding based on Angle of Arrival (AoA). This provides an opportunity to locate BLE devices, i.e., pinpoint locations of construction tools on site.

Ideally, object localization in 3D requires both direction (angle) and range between the locator and the device. Even though the AoA feature does not aim at ranging, an initial study showed that ranging should also be possible using the so-called constant-tone extension (CTE) and the frequency hopping feature of the BLE standard. The CTE feature of BLE provides the possibility of measuring the phase of received signals. This may allow for ranging using the phase differences between transmissions on different frequencies. However, as shown by a previous investigation, direct phase measurements provide insufficient accuracy, so a major challenge is to design an algorithm that enables accurate distance estimation from phase measurements.

Description:

The purpose of this assignment is to continue the existing work and develop a solution for estimating the distance from a device to a locator, using commercial off-the-shelf BLE hardware that includes the AoA/CTE feature. Some elements of this assignment are:

• Investigate the BLE AoA/CTE feature;
• Investigate principles for estimating distance using phase difference and multiple frequencies;
• Investigate the stability of phase measurements in commercial off-the-shelf BLE hardware;
• Design one, or more, algorithms for estimating the distance between a device and a locator;
• Optimize the algorithm(s) using simulation;
• Build a proof-of-concept (PoC) demonstrator using off-the-shelf evaluation boards;
• Measure performance in the PoC.

This assignment is conducted in close cooperation with the BouWatch research and development department.

Requirements:

You need MATLAB coding skills. Basic knowledge of wireless communications or willingness to learn it is needed.

Additional Info