Toward Reliable Localization with a Single Unaided Receiver by AoA

In recent years, most indoor localization systems coordinate the angle of arrival (AoA) of multiple access points (APs) for triangulation or sacrifice the availability of the system in order to obtain accurate time of flight (ToF), which is not conducive to the actual deployment of the system. The recent standardization by IEEE of Fine Timing Measurement (FTM), a native firmware implementation ToF based approach for ranging. In this way, we can pay more attention to AoA-based localization system. We present SAP-AoA, a WIFI based localization system, which only requires one AP and one channel to complete localization. To accomplish this, we use two incident angles and the distance between two antennas to determine the unique constraint of the target, and then search the localization field to get the target. At the same time, we simulate the FTM value and use it with SAP-AoA to obtain better positioning accuracy. We implemented SAP-AoA using Intel 5300 commodity WIFI cards and deployed it in four environments with different multipath propagation. Results indicate the best median localization error is 0.85m.