An optical sensor and method for detecting a projectile velocity vector includes
optically detecting the arrival of a projectile. The sensor includes a sandwich
of a transparent layer within two reflective layers, which in turn are within two
opaque layers. An optical sensor structure includes a set of sensors positioned
in respective planes, wherein at least two non-parallel optical sensors are used
for each trajectory dimension of interest that differs from the primary direction
of motion of the projectile and one additional optical sensor may be used for independent
measurement of velocity attenuation. An optical sensor structure includes a set
of sensors positioned in respective planes, wherein at least two of the optical
sensors are oriented in respective planes that are parallel and potentially offset
from each other. A tiling of the optical sensors or optical structures is also possible.