This thesis proposes the novel use of spinning beacons for precise indoor localization. The proposed “SpinLoc” (Spinning Indoor Localization) system uses “spinning” (i.e., rotating) beacons to create and detect predictable and highly distinguishable Doppler signals for sub-meter localization accuracy. The system analyzes Doppler frequency shifts of signals from spinning beacons, which are then used to find the direction from the spinning center to the target. By obtaining direction of the target from two or more spinning beacons, SpinLoc can precisely locate stationary targets. After designing and implementing the system using MICA2 motes, its performance was tested in an indoor garage environment. The experimental results revealed a median error of 40~50 centimeters and a 90% error of 70~90 centimeters.