Design and Analysis of a Prototype Range Correction Device for a Mortar Projectile

摘要

The primary purpose of the Light Forces Program is to improve the effectiveness of indirect fire from the infantry mortar without increasing the logistics burden on the soldier. Technology will enable improvements in mortar launcher design, aiming, meterological data, and projectile design. Advances in microelectronics, sensors, and power supplies make it possible to design and build a miniature, one dimensional range correction device for the mortar. The objective of a range correction device is to provide a smart munition capability of reducing range error, thus increasing the lethality. Another objective is to place the device between the existing fuze and mortar projectile without impinging on the fuze function and the aerodynamics of the projectile. The device must also be miniature to reduce the impact in logistics or cost. A more definitive explanation of the range correction idea for a mortar is as follows. The device is assembled onto the projectile while in the field. An on-board central processing unit (CPU) is preprogrammed with the target location and the firing location coordinates. The mortar is then aimed to fire beyond the target location. An on-board inertial measurement unit (IMU) determines the range error with respect to the target while the projectile is in flight. The CPU predicts the amount of excessive range that the mortar will have. At a certain time in flight, chosen by the CPU, the range correction device deploys eight small, flat, planar surfaces or flare tabs. The effect is to create more drag on the projectile to correct for the over shoot, thus reducing the range error aspect of the flight. This report focuses on one specific range correction concept and the progress of the design; it also covers the mechanical design of the flare tab mechanisms, the electronics volume, and the structural analysis of the overall design.