Study on linear field of strapdown semi-active laser seeker

Considering the requirement on the wide linear field of the strapdown semi-active laser seeker, the relationship of linear field for four-quadrant detecting(QD) photoelectric system and target distance was analyzed. First, according to the system parameters, the relationship of target distance on different visibility, different target reflectivity and the received power for the laser seeker was calculated. Then by ray tracing method, the power distribution on quadrant detector for different field was found. Finally, the relationship of linear field and the received power was obtained. Linear field increased from zero to the theoretical value of optical design with the target distance decreasing. Experimental results indicate that linear field increases from 0° to ±9° with the received power increasing, which agrees well with the result of theoretic computation. The change law of the linear field should be considered for stapdown semi-active laser system design.