Geospatial analysis of the system response time of satellite constellations with inter-satellite links

Abstract A new approach for estimating the system response time (SRT) is presented and demonstrated through the analysis of the effect of target latitude on SRT, both with and without inter-satellite links (ISL). The access time intervals for each satellite to ground stations, targets, and between pairs of satellites are computed. The SRT for a target is calculated using a proposed algorithm that includes an adapted Dijkstra algorithm on a time-varying link graph for the ISLs. For the geospatial analysis, the average, minimum, and maximum SRTs of the targets of all SRTs were introduced as performance metrics. Combined with a visualization on a world map, this method allows us to quickly grasp the strengths and weaknesses of the constellation with regards to SRT. When plotted as a function of latitude [− 90°, 90°], the SRT for constellations with and without ISL in mid and high-inclination orbits peaks at the equator and drops towards the Earth’s poles, influenced by the satellite constellation and ground station network design. ISLs smoothen the SRT curve and reduce the effect of the latitude, thereby enhancing data acquisition speed by minimizing SRT variation over time and across longitudes.