红外扫描器用于跟踪时基本上是一台光学换能器,其输出是一个电压,它相当于目标图象相对于扫描器视场中心的位置。假定相对于任意参考源目标的角位置是θ_T,光轴(视场中心)的角位置是θ_S,那么误差角θ_E是θ_E=θ_T-θ_S(4-25)一般说来,两个正交轴(如方位和俯仰)都要求误差角。图4-4是一个轴的跟踪回路简化方框图。扫描器装在稳定平台上,相当于θ_E的电压输出馈入力矩马达,后者在适当方向上移动扫描器,减小或消除θ_E。如果目标移动并改变其角位置θ_T,就产生新的误差信号, An infrared scanner is basically an optical transducer used for tracking. Its output is a voltage which corresponds to the position of the target image with respect to the center of the scanner’s field of view. Assuming that the angular position relative to any reference source target is θ_T and the angular position of the optical axis (center of field of view) is θ_S, the error angle θ_E is θ_E = θ_T-θ_S (4-25) Generally speaking, two orthogonal axes (Such as position and pitch) require the error angle. Figure 4-4 is a simplified block diagram of the tracking loop for an axis. The scanner is mounted on a stable platform and the voltage output equivalent to θ_E is fed into the torque motor, which moves the scanner in the proper direction to reduce or eliminate θ_E. If the target moves and changes its angular position θ_T, a new error signal is generated,