Retroreflector array and cover for optical bullet tracking
Systems, devices, and methods including a bullet; a retroreflector array adhered to a base of the bullet, the retroreflector array having prism facets with a periodicity between 0.2 mm-2.0 mm; and a cover disposed over the retroreflector array and hermetically sealed at the base of the bullet; where the cover is disposed over the retroreflector array in a first position prior to firing, and where the cover is released from the base of the bullet in a second position after firing.
1. A system comprising:
a bullet;
a retroreflector array adhered to a base of the bullet, the retroreflector array having prism facets with a periodicity between 0.2 mm-2.0 mm;
a cover disposed over the retroreflector array and hermetically sealed at the base of the bullet; and
an o-ring disposed between the cover and the base of the bullet, the o-ring hermetically sealing the retroreflector array at the base of the bullet;
wherein the cover is disposed over the retroreflector array in a first position prior to firing, and wherein the cover is released from the base of the bullet in a second position after firing.
2. The system of claim 1 wherein the prism facets of the retroreflector array have a periodicity between 0.3 mm-1.0 mm.
3. The system of claim 1 wherein the retroreflector array is disposed on top of the base of the bullet.
4. The system of claim 3 wherein the cover is clamped onto a perimeter of the retroreflector array.
5. The system of claim 1 wherein the bullet comprises an indentation in the base of the bullet, and wherein the retroreflector array is disposed in the indentation in the base of the bullet.
6. The system of claim 5 wherein the cover is clamped onto the base of the bullet.
7. The system of claim 6 wherein the base of the bullet comprises three or more equidistant dimples cut into the base of the bullet.
8. The system of claim 7 wherein the cover comprises three or more equidistant fingers that mate into each of the three or more equidistant dimples.
9. The system of claim 8 wherein the three or more equidistant fingers detach from the three or more equidistant dimples in the second position due to at least one of: wind resistance on the three or more equidistant fingers and centrifugal force on the cover.
10. The system of claim 1 wherein the cover is released from the base of the bullet in the second position due to deformation from centrifugal force.
11. The system of claim 1 further comprising:
a pressure sensitive adhesive disposed between the cover and the base of the bullet, the pressure sensitive adhesive sealing the retroreflector array at the base of the bullet.
12. The system of claim 1 wherein the hermetical seal is broken in the second position due to at least one of: degradation of the pressure sensitive adhesive after firing and deformation of the cover from centrifugal force.
13. The system of claim 1 wherein the retroreflector array further comprises:
an optical quality surface;
an optical polymer disposed between the optical quality surface and the prism facets, wherein the optical polymer transmits light with no loss;
a reflective coating disposed on a surface of the prism facets; and
a polymer encapsulating the prism facets.
14. The system of claim 1 wherein the periodicity of the prism facets enables laser light reflected back from the retroreflector array to encounter pseudo-phase conjugation during bullet flight.
15. A method comprising:
adhering a retroreflector array to a base of a bullet, the retroreflector array having prism facets with a periodicity between 0.3 mm-1.0 mm; and
attaching a cover over the retroreflector array such that the retroreflector array is hermetically sealed at the base of the bullet;
wherein the cover is disposed over the retroreflector array in a first position prior to firing, and wherein the cover is released from the base of the bullet in a second position after firing.
16. The method of claim 15 further comprising:
creating an indentation in the base of the bullet, wherein the retroreflector array is disposed in the indentation in the base of the bullet; and
creating three or more equidistant dimples in the base of the bullet, wherein the three or more equidistant dimples mate into each of three or more equidistant fingers of the cover.
17. The method of claim 15 wherein laser light reflected back from the retroreflector array encounters pseudo-phase conjugation during bullet flight.
18. A bullet comprising:
a retroreflector array adhered to a base of the bullet, the retroreflector array having prism facets with a periodicity between 0.2 mm-2.0 mm;
wherein a cover is disposed over the retroreflector array and hermetically sealed at the base of the bullet in a first position prior to firing, and wherein the cover is released from the base of the bullet in a second position after firing; and wherein the base of the bullet comprises three or more equidistant dimples cut into the base of the bullet and the cover comprises three or more equidistant fingers that mate into each of the three or more equidistant dimples.
19. The bullet of claim 1 wherein the retroreflector array further comprises:
an optical quality surface;
an optical polymer disposed between the optical quality surface and the prism facets, wherein the optical polymer transmit light with no loss;
a reflective coating disposed on a surface of the prism facets; and
a polymer encapsulating the prism facets.
20. A system comprising:
a bullet;
a retroreflector array adhered to a base of the bullet;
a cover disposed over the retroreflector array and hermetically sealed at the base of the bullet; and
a pressure sensitive adhesive disposed between the cover and the base of the bullet, the pressure sensitive adhesive sealing the retroreflector array at the base of the bullet;
wherein the cover is disposed over the retroreflector array in a first position prior to firing, and wherein the cover is released from the base of the bullet in a second position after firing.