What is angle of arrival tracking

In many fields such as wireless communication, radar detection, and sonar positioning, accurate acquisition and positioning of signals are crucial. Angle of arrival tracking technology, as a key spatial signal processing method, provides efficient and accurate solutions for these fields.

Simply put, it is to determine the angle of arrival of the signal source relative to the receiving system by analyzing and processing the received signal, and track the change of the angle in real time. This technology is based on the physical characteristics of signal propagation. When the signal reaches the receiving array from different directions, due to the difference in propagation paths, the signals received by each sensor in the array will have different amplitudes, phases, or time delays. The angle of arrival tracking technology uses these differences to calculate the angle of arrival of the signal through specific algorithms and models, and continuously tracks it.

In the field of wireless communication, angle of arrival tracking technology has a wide range of applications. Taking Bluetooth Low Energy (BLE) technology as an example, as it develops to version 5.2 and above, the positioning tracking function has become a highlight. In indoor positioning scenarios, by placing antenna arrays in buildings and using angle of arrival tracking technology, the movement and positioning tracking of assets can be achieved. Specifically, a Bluetooth transmitter (AoA tag) sends a Constant Frequency Extension (CTE) signal that propagates outward in an expanding spherical pattern and is received by an antenna. Since the wavelength and frequency of the signal are known, and the distance between the receivers is also known, the angle of the signal can be calculated using relatively simple triangulation to determine the position of the transmitter based on the phase difference when the signal reaches each antenna. By using two pairs of antennas to perform two detections, the exact location of the AoA tag can be triangulated with extremely high accuracy. This technology can be used in the retail industry to better understand the flow of customers in the store to maximize sales potential, and in the industrial field to monitor material transportation vehicles, reduce time waste, and improve work efficiency.

Angle of arrival tracking also plays an integral role in radar detection systems. Radar systems use this technology to determine information such as the location, speed, and movement trajectory of a target by transmitting electromagnetic waves and receiving the signals reflected back from the target. For example, in a monopulse radar, multiple feeds are used to form multiple beams at the same time. The echo of the target will enter different feeds. By comparing the strength of different beams by sum and difference, the position of the target relative to the antenna is determined, and then the antenna is controlled to turn to the target to achieve accurate tracking of the target. This technology is of great significance in military defense, air traffic control and other fields, and can provide timely and accurate intelligence support for decision-making.

The field of sonar positioning is also inseparable from the angle of arrival tracking technology. In an underwater environment, sound waves are the main propagation medium. The sonar system uses this technology to determine the position of submarines or other underwater targets by emitting sound wave signals and receiving signals reflected by the target. Due to the complexity of the underwater environment and the characteristics of sound wave propagation, the angle of arrival tracking technology needs to overcome many difficulties such as multipath effects and noise interference, but by continuously optimizing algorithms and improving equipment performance, high positioning accuracy can still be achieved.

However, the angle of arrival tracking technology also faces some challenges. In practical applications, multipath effects, signal noise, clock jitter, signal propagation delay, and switching timing will affect the estimation accuracy of the angle of arrival. In addition, factors such as the design and layout of the antenna array and the computational complexity of the algorithm will also affect the performance of arrival angle tracking. In order to overcome these challenges, researchers continue to explore new algorithms and technologies, such as the application of compressed sensing theory in DOA tracking. After windowing and SVD processing of the data, the change of DOA is estimated using the Bayesian sparse reconstruction method of the deviated grid under the framework of sparse theory, which improves the tracking accuracy and resolution, and has good tracking performance when the signal source is coherent or the motion trajectory is close.

As an important means of spatial signal processing, arrival angle tracking technology plays a key role in wireless communications, radar detection, sonar positioning and other fields. With the continuous development and innovation of technology, it is believed that it will be widely used in more fields, bringing more convenience and benefits to our lives and work.