Patent ID: 10257655

Abstract:
A method for generating contact graphs for delay/disruption tolerant networking for a constellation of network nodes (e.g., satellites in low earth orbit, terrestrial sensors, and ground stations). A contact graph indicates the availability and data rates for communications links between spacecraft and ground stations. The links may be intermittent due to orbital dynamics and the earth's rotation, and may be line-of-sight or relayed. The method predicts the future locations of satellite nodes in the Earth Centered inertial reference frame, and converts the locations of terrestrial nodes by converting their coordinates from the Earth Centered Earth Fixed reference frame. The method also determines whether line-of-sight links are possible, and estimates the closing velocity between network nodes to estimate signal Doppler shift. Contact graph routing determines the links used to most effectively move data over the network. Output data files may be directly used by Interplanetary Overlay Network administration software.