Sky Curtain Sensor Based On Laser Reflection

The sky detection measurement technology is widely used in the projectile flight parameter, existing sky detector detecting the presence of low sensitivity, susceptible to sky brightness effect, not working at night of sky screen now, in view of the these problems, put forward a kind of active screen laser reflection detection scheme based on the scheme, the line structured light semiconductor laser as the active light source, optical lens, the slit diaphragm, filter and photomultiplier tube optical detection system. When the projectile through the detection light curtain, the structure light semiconductor laser and optical detection system composed of. The part of the light reflected back to the body surface received by the optical detection system, and then output an analog signal and pulse signal corresponding to the moments of the flying projectile through the probe screen surface, by the photoelectric detector photoelectric conversion and the subsequent signal processing of the circuit of photoelectric detector generation.1) Studied the types and characteristics of the detection light source, determined the canopy detector light semiconductor laser to the word line structure of active light source, through the comparison of incandescent, fluorescent, light-emitting diodes and lasers, the parameters of the analysis of each light source, and study of the material properties of the elastomer.2) Designed an atrium detector based on the principle of reflection of the active laser optical system; the use of the slit diaphragm and the optical lens is formed in the space having a certain thickness of the fan-shaped light curtain with the semiconductor laser generates a fan-shaped light curtain composed detect light curtain, obtained optional optical lens focal length of 50mm, the maximum detection field angle of 26.9; selected the appropriate narrow-band filter with the wavelength of the laser light source, effectively filter out the rest of the band stray light, improving system detection sensitivity; according to the system requirements, selected CR131 type HAMAMATSU photomultiplier tube a photoelectric conversion device as a canopy detector and the photoelectric conversion efficiency, as well as the spectral responsivity, and to achieve a photoelectric conversion of the reflected light signal of the elastomer.3) Canopy detector based mechanism, detection conditions and requirements of the overall structure mechanical structure of tent detector is designed, determined the optical lens, a major component of line structured light semiconductor laser, photoelectric detector and photoelectric signal conversion circuit between the fixation and installation, draw the system assembly drawings and part drawings completed the drawing processing as well as the assembly and adjustment of the prototype. Got the signal produced by the light energy and laser export power, flying objects, the diameter of laser angle, the lens aperture and lens distance flying object relative to the ratio between by analysis of the sensitivity of detection model system.4) Electrical signals produced by the photomultiplier tube signal processing circuit for amplifying, filtering and denoising processing, analog and digital signals corresponding to the final output through the detection screen time. The design of the preamplifier circuit, realized the conversion between the current and voltage, a post-amplifier circuit using two inverting amplifier voltage signal and three in the same direction magnified 60 times, and the RC filter circuit filter 1KHz～50KMHz signal outside, the output of the corresponding the projectile crossing detection light curtain time analog and digital signals., through playing the size of air gun bullet live-fire test of 4.5mm, the maximum detection height of 1.1m, test the sensitivity reached 245 times the diameter of projectile, basic to meet the practical requirements of shooting range test.