Improving the Tracking Error Signal Extraction in IR Seeker with Stationary Wagon Wheel Reticle over all Field of View

The accuracy of target position detection in IR seeker depends on the accuracy of tracking error signal (TES) extraction from seeker Field of View (FOV). The type of reticle inside the seeker determines the output modulation signal that carries the TES. In this paper, the stationary wagon wheel reticle is used, which makes the type of the output signal as FM modulation in the linear region of FOV, but the signal will be distorted by changing the radius of target image spot (TIS) and in the nonlinear region of FOV. Firstly, we applied the Hilbert transform algorithm for the first time in this field and compared it with the conventional algorithm in the linear region of FOV to decrease the effect of changing the radius of TIS. Secondly, we presented a new method in the nonlinear region to extract the TES. The results show improvement in TES accuracy extraction in the linear and nonlinear region over the FOV for different radii of TIS.