天基空间目标监视系统是获取空间目标态势信息的重要手段和未来发展方向，然而仅仅利用星间测量信息进行空间目标轨道确定会产生亏秩现象。在对自主定轨亏秩问题的本质进行探讨的基础上，提出了基于天地基测控信息进行空间目标和监视平台的联合定轨策略，可以较好地解决轨道确定中亏秩问题。本文设计了由四颗高轨监视平台和两个地面测控站构成的天地测控网，仿真实现了该系统对空间目标的定轨功能。仿真实验表明基于联合定轨策略的三类空间目标轨道确定精度可达公里级水平。

The Space-Based Space Surveillance (SBSS) system is an important way and the development tendency of accepting state information of space objects. However，only utilizing the measure information between the satellites would produce the deficient–rank phenomena in the process of orbit determination of space objects. The essence of deficient-rank problem in the autonomous orbit determination was discussed. The problem can be eliminated by the combined orbit determination strategy based on space/ground-based tracking telemetry and command technology. The tracking network was made up of 4 high-orbit surveillance platforms and 2 ground surveillance stations. The orbit determination function of the system for the space objects was simulated. Simulation experiment shows the orbit determination precision for three kinds of space objects based on the combined orbit determination strategy reaches kilometer level.