Determining communication windows

An apparatus comprising:

• a processor executing code stored on a memory to perform:
• generating a communication graph comprising backbone nodes, dummy nodes, data collection nodes, downlink nodes, crosslink send nodes, and crosslink receive nodes, wherein the backbone nodes, the data collection nodes, the downlink nodes, the crosslink-transmit nodes, and the crosslink-receive nodes are connected by one of a homogenous edge between nodes of a same type and transition edges between nodes of a different type;
• determining access windows for downlink communications and crosslink communications using the communication graph, wherein each access window comprises a temporal constraint defining a time interval for performing a given downlink communication and a spatial constraint for performing the given communication;
• generating task nodes for a task graph from the access windows and imaging task, wherein each access window, imaging task starting position, and ending position is represented as a task mode;
• establishing edges by connecting each task node to a feasible subsequent task node with an edge subject to a maximum number of group nodes and a maximum number of total nodes;
• calculating a score and cost for each task node and edge based on an imaging task value;
• applying constraints;
• solving for an optimal path for the access windows;
• selecting access windows based on the task graph generated from the communication graph;
• and
• communicating from a given satellite within the selected access windows.

A computer program product comprising a non-transitory storage medium storing code executable by a processor to perform:

• generating a communication graph comprising backbone nodes, dummy nodes, data collection nodes, downlink nodes, crosslink send nodes, and crosslink receive nodes, wherein the backbone nodes, the data collection nodes, the downlink nodes, the crosslink-transmit nodes, and the crosslink-receive nodes are connected by one of a homogenous edge between nodes of a same type and transition edges between nodes of a different type;
• determining access windows for downlink communications and crosslink communications using the communication graph, wherein each access window comprises a temporal constraint defining a time interval for performing a given downlink communication and a spatial constraint for performing be given communication;
• generating task nodes for a task graph from the access windows and imaging task, wherein each access window, imaging task starting position, and ending position is represented as a task mode;
• establishing edges by connecting each task node to a feasible subsequent task node with an edge subject to a maximum number of group nodes and a maximum number of total nodes;
• calculating a score and cost for each task node and edge based on an imaging task valve;
• applying constraints;
• solving for an optimal path for the access windows;
• selecting access windows based on the task graph generated from the communication graph;
• and
• communicating from a given satellite within the selected access windows.