In order to improve the helicopter operation safety in complex terrain or brown-out environments, a Blade-Tip close warning situation awareness Laser System (BTLS) with the detection range of 360-degree circumferential directions and the height direction to improve the helicopter situational awareness ability is proposed. The BTLS consists of blade-tip orthogonal laser transmitters, fuselage laser receiver array, and the laser drive controller, in which the transmitters, receivers, and fiber optic connections are all redundant. The most important feature of the BTLS is the two orthogonal directions of the transmitters installed in the blade-tip, using the helicopter itself rotating parts-blades to achieve quick scan of 360-degree circumferential directions and the height direction, thus overcoming the disadvantages of existing laser detectors of complex scan mechanism, lack detection range and installation location restrictions. The effects of the three angles of the helicopter blade in normal flight states and the helicopter pitch angle in high speed forward flight state on the BTLS performance are analyzed. The results showed that the BTLS has less 4% relative error whatever in circumferential directions or in height direction at the normal flight states except at the high speed forward flight state, there was a blind area in front. The BTLS is light weight, low power consumption, wide detection range, flexible installation location, high reliability, having high research value and good prospects.
