Fixed-Time Delay Calculation Method Based on Fuze-Warhead Coordination: Approach Cases and Application to The Small Target Platform

ABSTRACT This paper presents a method for calculating the delay time and determining the fixed delay components for laser fuzes installed on man-portable air defense systems (MANPADS), targeting small aerial vehicles such as cruise missiles. The method is based on the “kinematic-geometric” relationship between the missile, fragments, and the target, ensuring that the average fragment trajectory passes through the target’s center. Approach scenarios are divided into zones, with each zone using a common delay component. The laser beam’s inclination angle is aligned with the average fragment trajectory, ensuring delay time independence from miss distance. The approach zones are defined by kinematic relationships, including head-on or tail-chase modes and the azimuth angle. The delay time for each zone is calculated as the average delay across all scenarios within that zone. The method eliminates the effect of miss distance, with delay components dependent only on the missile’s direction of motion. A case study applying the model shows minimal error when using the average miss distance, and the results confirm that the fragment stream consistently hits the target across all approach scenarios. The proposed method offers an effective solution for accurately determining delay time and optimizing fuze performance in MANPADS.