Application Study of BRDF on Measuring Projectile Position in Multi-stage Coilgun

摘要

The BRDF (bidirectional reflectance distribution function) perfectly describes the hemispherical spatial reflected characteristics and spectral characteristics of material surfaces, and the coilgun has important application prospect in space navigation and national defence. The application of BRDF on measuring projectile position in multi-stage coilgun is studied. The concept and the measuring theory of BRDF are discussed. A set of system based on personal computer for BRDF measurement is developed. The measuring experiment of BRDF on Aluminum piece is done using single reference method at normal incidence by 0.6328 μm laser, the values of BRDF from different scatter angle can be attained by the above experiment. We design the multi-stage coilgun system, in which the projectile position of coil electromagnetic launch can be determined by those measured values of BRDF. No matter how many stages the driving coil adopts, only one set of the optical irradiation-receiver unit is needed. Results show the configuration of the multi-stage coilgun becomes very simple and the projectile is easy to be controlled based on the bidirectional reflectance measurement technique.