Improved Tracking Systems With Adaptive Gates

Range and bearing navigation is commonly used in many autonomous systems such as autonomous guided vehicles and freely moving platforms. The measurements obtained are accompanied by noise and are subjected to possible errors, which consequently may lead to wrong decisions made by the control and guidance system. An improved method is applied for filtering unexpected high measurement noise due to clutter, glittering, or shaking of the measuring system. Optimal correlation gates around the predicted values of the signal states — the position of the target — reduce the unexpected noise effect. The optimal threshold for the correlation gates is determined off-line by simulation or, adaptively, by online estimations. Values of measurements not in the gates are ignored and the integration of the prediction model for the tracked signal continues until a new measurement is received within the gate opening. The dimensions of the correlation gates are determined by the filter predictions and the normal error variances of the measurement.