# A Space-Interconnection Algorithm for Satellite Constellation Based on Spatial Grid Model
## 5 Conclusions  
This research is based on the background of space-based big data and satellite Internet, combined with low-orbit satellite constellations and a complex network communication environment, in particular the construction of the PNTRC system. To address the bottlenecks in large-scale node space computing, we introduced a global space grid, GeoSOT-3D. Based on this grid, an efficient calculation method of spatial inter-connection between satellite constellations is proposed, according to the concept of \"storage for computing\" and the high computational efficiency of the spatial grid model. The foundation of this method is to establish an aerospace grid indexing BigTable with grid code as the primary key correlating spatial information. The satellite trajectories and resources are grid modeled separately. When distant satellite resources cannot be directly transmitted to ground users, inter-satellite data transmission is required. This process involves establishing a grid virtual node model, using the virtual topology, querying the grid through the BigTable, and iterating to meet the coverage requirements of the inter-satellite transmission path. The experiment started with the establishment of the aerospace grid indexing BigTable, and verified the feasibility and efficiency of the inter-satellite computing and application process of organization, storage, calculation, and planning. This \"space-for-time\" approach has efficiency advantages in inter-satellite interconnected computing. After considering the actual physical expenses, the efficiency of visibility analysis was increased by 23.62 times and the efficiency of route planning increased by 29.74 times.  
The application and development of the grid inter-satellite connection and calculation algorithm proposed in this study will be conducive to the construction of a location-based integrated network communication between satellites and earth as well as the realization of more efficient space-based information intelligent services. However, since this is the first study on application of the grid system to the interconnection algorithm of low-orbit satellite constellations, there are still many issues worthy of in-depth study. These include: index optimization of the aerospace grid indexing BigTable, storage optimization of the on-board algorithm, optimization of the multi-task and multi-object algorithm of the dynamic planning of inter-satellite routing, amongst others. The spatial interconnection algorithm is not only applicable to remote sensing constellations but is also applicable to other constellations that require interconnection, such as communication and navigation. We hope that the algorithm can be used in emergency communications, disaster warning, and maritime rescue, and can contribute to the next generation of satellite Internet and \"satellite-ground\" integrated networks.  
[PERSON]. ([PERSON]) conceived, designed, and performed the experiments and wrote the manuscript; [PERSON] helped perform the experiments and offered helpful suggestions for experiments; [PERSON] supervised the study; [PERSON]. ([PERSON]) offered helpful suggestions and provided some data; [PERSON] offered helpful suggestions and reviewed the manuscript. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Key Research and Development Plan (Grant No. 2018 YFB0505300).  
The authors declare no conflict of interest.