Overview of SC Modeler 4.1

The SC Modeler software is a comprehensive tool for the conceptual design, visualization, and analysis of satellite networks, ranging from small groups of interconnected satellites to extensive multi-layered satellite constellations. It provides an integrated modeling environment and essential functionality that enables rapid development, visualization, and analysis of satellite constellation design alternatives, facilitating performance comparison of satellite network variants at the architectural level.

SC Modeler comes with multiple options for designing new satellite constellations or defining the orbital parameters of existing ones:

• Specifying orbital parameters of satellites or satellite groups using the Constellation Editor tool.
• Importing TLE data (example).
• Generating constellation designs for continuous or periodic coverage using the Constellation Design modules (examples).

SC Modeler includes the Two-Body Keplerian, J2 Perturbations (no drag effects), and SGP4/SDP4 orbit propagators. (more)

Users can create static or animated 2D or 3D views of the constellation and interactively examine it by adjusting the azimuth and elevation of the viewpoint, rotating or moving the view, moving the ground stations, and zooming in or out. The viewpoint can be placed above a satellite or ground station.

The software allows for the visualization and analysis of all intersatellite links, all communication links to a specific ground station or satellite, or a chain of communication links between any pair of network nodes: "ground station-ground station," "ground station-satellite," "satellite-satellite."

SC Modeler employs a hierarchical routing algorithm that enables a fast and accurate search for the shortest path between the source node and the destination node in accordance with the chosen routing policy. This capability persists even for large, multi-layered mega-constellations comprising thousands of satellites.

During simulations, either in "fast" or real-time mode, the program generates and continuously refreshes charts, histograms, and textual reports characterizing the network topology, route stability, properties of active communication links, and revisit characteristics. These include the number of potential connections available to a ground station or satellite, total path length (edges or km) and delay, route duration, length of uplinks, downlinks, and intersatellite links, intersatellite range rate and relative velocity, access intervals and service gaps, and more.

The software also allows you to determine visibility intervals when the required number of satellites is available to a ground station or satellite. Historical data related to communication route changes can be collected and reviewed.

The software includes a set of productivity tools that offers an efficient and convenient way of managing model properties, constellation parameters, and design constraints.

The Access Constraints tool allows you to define one or multiple Earth observation sensors, uplinks, or downlinks with conic, rectangular, or custom field of view for a single satellite or a group of satellites. It enables you to establish access constraints specific to these components and specify the boresight orientation.

Constellation Design Modules
Constellation Design modules implement highly optimized search algorithms capable of producing an efficient constellation design for global or zonal, continuous or periodic coverage in a matter of seconds.

The Continuous Coverage Constellation Design/Circular Orbits module allows you to consider symmetric constellations (known as "Walker delta" constellations) and "streets of coverage" constellations with polar or inclined orbits (examples).

The Continuous Coverage Constellation Design/Advanced Options module generates kinematically regular patterns with circular or elliptical orbits where all orbits have the same altitude, inclination, and argument of perigee. The generated constellation design should ensure the continuous availability of a specified number of satellites above the region of interest (examples).

The Continuous Coverage Constellation Design/Advanced Options Plus module provides all the capabilities of the Continuous Coverage Constellation Design/Advanced Options module. In addition, this module generates kinematically symmetric constellation design patterns, which, in certain cases, perform better than "streets of coverage" and "Walker delta" constellations (example).

The Periodic Coverage Constellation Design/Circular Orbits module generates kinematically regular patterns with circular orbits ("Walker delta" constellations) that provide the required maximum revisit time for given latitude bounds (examples).

Constellation Design modules can help you to minimize the number of satellites required by the constellation if orbital inclination and altitude are specified. Alternatively, you can minimize the altitude of orbit for a given number of satellites and the orbit inclination.

Other inputs of the design task are:

• Coverage area - entire Earth or latitude bounds.
• Constellation design constraints - number of orbital planes and number of satellites per plane (min and max).
• Access constraints - minimum ground elevation angle, maximum satellite sensor's field-of-view (conical half-angle), maximum ground station to satellite propagation range.

• Number of intraplane links, which connect a satellite to its nearest neighbors within the same plane.
• The relative position of orbits of satellites connected via interplane links (relative plane number).
• Number of interplane links, which connect a satellite to its nearest neighbors in co-rotating or counter-rotating planes.
• Latitude range of a subsatellite point when intersatellite links of a given type are active.
• The group of satellites (subconstellation) for which the specified set of links is valid.

• Routing policy that minimizes the number of hops across the satellite (this policy is part of the base product and is selected by default).
• Routing policy that minimizes the number of hops (first) and the total length of the path from the source node to the destination node (second).
• Routing policy that minimizes the total length of the path from the source node to the destination node.
• Routing policy that minimizes the total delay, which includes the propagation, transmission, queuing, and processing delays along the path.