Study on position detection method of multi-stage coilgun projectile

The coilgun has important application prospect in space navigation and national defense, but the position of the projectile is difficult to decide. BRDF (bidirectional reflectance distribution function) perfectly describes the hemispherical spatial reflected characteristics and scattering characteristics of material surfaces. The application of BRDF on measuring projectile position in multi-stage coilgun is studied in this paper. The concept and the measurement theory of BRDF are discussed, and the system equation of multi-stage coilgun is analyzed. The position detection system of multi-stage coilgun projectile is designed based on the BRDF value. Results show that, no matter how many stages the driving coil adopts, only one set of the optical irradiation-receiver unit is needed. The position detection system of multi-stage coilgun becomes very simple and the projectile is easy to be controlled based on the BRDF measurement technique.