Efficient Small Angle-of-Arrival Array Sensor for Intelligent Localisation and Tracking Systems

In dynamic environments, it is expected both vehicular transmitter and receiver are moving and therefore the Angle of Arrival (AOA) information is changed during communication links. Thus, a continuous measurement for data obtaining should be made to predict the new direction and location of the targeted person accurately. In this regard, a fast AOA method that can use a single snapshot instead of multiple snapshots without sacrificing estimation accuracy is an urgent demand for direction estimation information. To this end, an efficient direction-finding method called, Inverse of Subtracting (IOS), which exploits a single eigenvector that associates with the maximum eigenvalue is proposed to overcome the intensive computations of the conventional AOA estimation techniques. An Orthogonal Frequency Division Multiplexing (OFDM) based on a wideband spectrum is adopted here as a modulation technique and then integrated with the IOS method to exploit the available bandwidth efficiently and to resist frequency selective fading and multipath effects. To cover 360 degrees during the tracking process, a compact-size helical sensor with an Omni-directional radiation pattern is selected and then a ring array is modelled based on five helical sensors.The sensor array is then combined with the OFDM-IOS scheme to determine the direction of the vehicle movement based on the most dominant received sub-carrier. The proposed system is applied to track and detect the location of a hidden object within an urban area and the results demonstrate the efficiency and superiority of the proposed AOA sensor array with less computational complexity.