基于轨道约束的空间目标球面网格索引及区域查询应用

针对海量、高速运动的空间目标检索查询效率低的问题，提出一种基于轨道约束的空间目标球面网格索引构建方法。该方法利用地球惯性系下空间目标轨道相对稳定的特性，通过维护球面剖分网格内途经的空间目标列表，实现了对高速运动目标的稳定索引。在此基础上，提出基于目标球面网格索引的区域查询应用方案，首先，依据一定步长离散查询时段；然后，计算查询区域在惯性空间的边界点坐标并确定交叉网格；其次，提取网格中的空间目标，计算并判断目标与区域的位置关系；最后，递归查询整个时段，实现空间目标过境查询分析。仿真实验中，传统逐目标查询方法耗时与目标数量线性正相关而与区域大小无关，单目标平均耗时0.09 ms；与之相比，所提方法用时随区域面积减小呈线性递减，区域格网数小于2750时，时间效率高于对比方法，且能够维持相当的准确率。实验结果表明，该方法在实际区域应用中可以有效提升查询的效率。

Space target sphere grid index based on orbit restraint and region query application

Since the efficiency of retrieval and query of mass and high-speed space targets remains in a low level, a construction method of sphere grid index to the space targets based on the orbit restraint was proposed. The advantage that the orbit of space target is relatively stable in earth inertial coordinate system was used in the method to achieve the stabilized index to high-speed moving objects by maintaining the list of the space targets that pass through the sphere subdivision grid. On this basis, a region query application scheme was proposed. Firstly, the query time period was dispersed according to a particular step value. Secondly, the boundary coordinates of the query region in the inertial space were calculated and the staggered mesh was confirmed. Then the space targets in the grid were extracted and the spatial relationship between targets and the region was calculated and estimated. Finally, the whole time period was queried recursively and the space targets transit query analysis was accomplished. In the simulation experiment, the consumed time of the traditional method by calculating one by one has a linear positive correlation with the target number, but it has no relevance with the region size. One target costs 0.09 ms on average. By contrast, the time of the proposed method in the paper shows a linear decrease with the decline of area size. When the number of the region grids is less than 2750, the time efficiency is higher than that of the comparison method. Furthermore, it can maintain a fairly good accuracy. The experimental results show that the proposed method can improve the efficiency of the query in the actual region application effectively.