jig system mil.

[paslonko]

Уважаемые переводчики, подскажите, пожалуйста, что такое jig system для данного контекста

When using photography or flash radiography, two orthogonal measurement planes shall be used to allow visualisation of yaw in both the horizontal “X” and vertical “Y” directions combined (Av and Ah).
With photographic systems, the use of a 45 degrees inclined mirror allows capture of two orthogonal images (actual side view and reflected top view) on a single image.
The mirror and camera jig system should be aligned to the flight of the bullet with an in-bore laser using two pin hole screens to ensure proper alignment with the launcher axis.
The images taken should also include a zero degree reference line from which each yaw component will be measured.

Заранее благодарю

[muzungu]

Я бы сказал "система крепления зеркала и фотокамеры".