Optex Systems has been awarded a contract by an undisclosed customer to upgrade the sighting system apparatus on a fleet of combat vehicles for the armed forces of a G-20 nation.

The five year subcontract for more than 500 units is part of an upgrade package for the fleet, under a separate modernisation contract awarded to the international defence contractor.

Optex general manager and CEO Danny Schoening said the upgrade on the sighting system apparatus will use digital day and night (DDAN) technology.

The technology will provide high definition digital video output for both day use and third generation 18mm image intensified technology for night use, Schoening added.

Deliveries under the $7.8m award are expected to begin in mid-2012.