红外线测距测向仪
infrared ranging and directing
视距测距仪
stadia metric range finder
[固]定[螺]距螺桨
fixed pitch propeller {= FPP
变螺距螺杆
Varying pitch screw
variabe pitch screw
pitch-varying spiral rod
change thread pitch screw
variable pitch screw
变螺距螺旋扫描
variable pitch helical scan