Deciding position direction or speed relative to chosen reference

摘要

The method uses acoustic sound waves emanating from a turbulent gas volume extending straight behind the projectile and or emanating from a wake or monopole existing straight behind the projectile. The waves are received by acoustic sensors (S1, S2 and S3). The time differences for the arrival of the waves to the sensors are measured. The projectile position (x1 and y1) in the first plane (35) is calculated from these time differences. The hit point of the projectile in a target plane (31) through the target is determined using the calculated projectile position in the first plane.