Traditional low & extra-low altitude threats have been widened in recent local wars.Targets such as stealth fighters,unmanned aerial vehicles (UAVs),smart and guided weapons have emerged and technical features such as low-infrared,high-maneuverability,strong antijamming and clustering trends have been presented,which lead international military users to raise new requirements for portable surface-to-air missiles (SAMs) beyond their traditional combat performances and shoulder-firing mode.To make a deep research on new international market demands,systematically study on technique performances and transfer quantity of mainstream 3rd-generation portable SAMs,compare the technical status of available portable SAMs,analyze the system technical index and sub-system technical developing trends of new-generation portable SAMs,as well as research the key techniques and solutions.The result shows that new-generation portable SAMs should possesses features including low-infrared-target interception,high guidance accuracy,strong antijamming performance,multi-mission and multi-platform expansion capability.

For the needs of maritime surveillance, an optical system of refrigeration infrared thermal imager is designed, for which the detectability is not less than 23 km for an over 500t level sea surface ship (greater than 10 m×10 m). The infrared detector is determined. The parameters such as focal length, zoom ratio and aperture are determined by the distance analysis. The detailed design for the optical system is performed according to the above parameters using Zemax software optical design. The imaging quality and aberration is analyzed. The detectability is verified by field experiment, which proves the rationality of design.