群小目标飞行特征显控系统利用上位机传送的数据实现弹道轨迹仿真，将仿真结果与理想的弹道轨迹进行比较，判断弹道轨迹精度是否能满足预期的发射要求，评估火力发射技术是否达到预期成果。针对系统中的弹道仿真功能提出了一种三维弹道轨迹插值拟合算法，将三维离散的特征数据分解到射面和炮口水平面2个二维平面，在二维平面分别采用分段三次样条插值算法对离散的特征数据进行插值拟合，再根据插值结果绘制三维弹道轨迹图像。使用VC++ 6.0编写插值拟合程序，通过实例验证拟合出的三维弹道轨迹经过每一个特征点且轨迹光滑连续，满足拟合条件，达到轨迹仿真的要求。

The system that displays and controls antiaircraft gun projectile flight characteristics uses data from host computers to realize 3D ballistic trajectory simulation, then compares the results with ideal ballistic trajectories in order to judge whether the accuracy of ballistic trajectory satisfies the requirements and to evaluate whether the firepower technology achieves the expected results. This paper briefly introduces the basic framework and functions of the system and presents a cubic spline interpolation fitting algorithm for 3D ballistic trajectory simulation. The algorithm decomposes the 3D discrete characteristic data into two 2D trajectories separately in the launch plane and the horizontal plane, then interpolates and fits them by a piecewise cubic spline interpolation algorithm respectively, and finally plots the 3D ballistic trajectory according to the interpolation results. The algorithm is realized by Microsoft Visual C++ 6.0. Through an evaluation instance, the 3D ballistic trajectory is shown to be smooth and can pass through each characteristic point, meeting the fitting condition as well as the requirement of trajectory simulation.