Fraunhofer Institute for Integrated Circuits IIS
Fraunhofer Institute for Integrated Circuits IIS
Key visual LEO simulation
© pickup – stock.adobe.com

Building Satellite Constellations in Simulation

© pickup – stock.adobe.com

Design and Optimization of LEO Satellite Constellations

Managing mega-constellations

Satellite constellations, comprising a large number of smaller satellites in low earth orbit (LEO), meet the growing demand for internet connectivity in remote regions, on ships and airplanes. In combination with functionalities such as user-to-user links and direct-to-device connectivity they offer great opportunities for secure, reliable and global coverage. Developing such mega constellations in non-geostationary orbit (NGSO) is all about meeting user demands, dealing with interference and tuning the operational settings:

System efficiency

Fine-tuning the number of satellites and their parameters to the demand on ground increases the profitability of a LEO system. At the same time, launch schedules and ground equipment lead time may result in incremental constellation build-up and changes may occur over time.

Coexistence management

New constellations need to coexist with hundreds of geosynchronous satellites and thousands in LEO. This requires detailed interference management, including self-interference and coordination with other LEO operators while protecting GEO satellites.

Operational optimization

Operational settings like beam steering and power must be optimized for maximum capacity without causing undue interference. Efficient traffic routing between satellites and Earth gateways is crucial to maximize throughput and minimize latency. 

Planning, simulating and optimizing system concepts

Detailed system simulations are essential for tailoring the performance of a satellite constellation to meet a wide range of efficiency, regulatory and operational constraints. While several commercial and open-source tools are available for simulation, analysis, and optimization of satellite systems, none of them comprehensively addresses all relevant aspects.

Our in-house simulation platform ConSim looks at the big picture and enables us to create precise virtual representations of planned or existing satellite constellations. ConSim allows us to conduct a variety of thorough and integrated simulations focused on orbital parameters, link budgets, system capacity and network efficiency.

Schematic representation of the functions of ConSim
© Fraunhofer IIS

Modeling and evaluation options

Expand all Close all

Constellation modeling for satellite positions and paths
© Map data from OpenStreetMap, https://www.openstreetmap.org/copyright

Constellation modeling for satellite positions and paths

Modeling of exisiting and planned systems

 

With ConSim we create detailed orbital models for NGSO constellations, accommodating hundreds or thousands of satellites across multiple orbital layers. The satellite positions and trajectories are precisely simulated and combined into an overall picture that provides fundamental insights into coverage patterns and orbital dynamics.

Through comprehensive visualization options, we make constellation design tangible and thereby support strategic planning and deployment of satellite networks.

By importing International Telecommunication Union (ITU) filings data and two-line element (TLE) files, we can accurately and flexibly represent existing satellite configurations. Additionally, we are able to design entirely new constellations that meet specific requirements.

Carrier to noise ratio (C/N) analysis in dB
© Map data from OpenStreetMap, https://www.openstreetmap.org/copyright

Carrier to noise ratio (C/N) analysis in dB

 

Thorough assessments of link budget performance help all stakeholders involved in the development of a LEO system to make informed decisions regarding system design and specific operational aspects. To ensure accurate modeling of communication links, we consider atmospheric conditions, satellite payload impairments, antenna characteristics and co- and cross-pol interference effects between satellites or satellite beams.

To evaluate regulatory compliance and optimize transmission schedules accordingly, we perform equivalent power flux density (EPFD) calculations according to Article 22 of the ITU radio regulations. Overall, this allows for unimpaired coexistence between geostationary and non-geostationary (GSO/NGSO) satellite systems.

Satellite broadband demand analysis in Mbps/km²
© Map data from OpenStreetMap, https://www.openstreetmap.org/copyright

Satellite broadband demand analysis in Mbps/km²

Matching demand and supply

 

To align end-user demand with available communication links, we simulate the overall capacity demand and the corresponding data flow through an existing or planned satellite system. This includes considering the geographical distribution of users and gateways, user activity and traffic patterns, as well as specific security constraints. For example, this may involve routing restrictions if data cannot leave a certain geographical area.

In our simulations with ConSim, user demand is efficiently mapped to specific links, and data is virtually routed. This allows for optimizing the resource allocation within a satellite network and adapting network configurations to meet evolving requirements.

Detailed visualizations and analyses provide valuable insights into the dynamics of supply and demand, in order to scale the network an optimize its performance.

Schematic example for the modeling of payload impairments
© Fraunhofer IIS

Payload impairment model example

Radio resource management for enhanced network efficiency

 

Radio resource management (RRM) regulates the coordination and allocation of limited radio resources in a satellite network. The goal is to adjust beam pointing, power levels, data scheduling and routing to achieve the most efficient network utilization possible.

With ConSim, we can provide insights into overall system performance and individual parameters and translate them into key performance indicators (KPIs) represented by histograms, charts, static maps and videos.

In an iterative optimization process, operational parameters can be precisely tuned through simulation until an ideal configuration is found. This way, even with changing requirements for a system, we can adjust and adapt the constellation system design.

Simulations and consulting for LEO constellations

Consulting for
constellation designs

 

Gain insights into optimal satellite configurations and coverage patterns through our scientific consulting on constellation designs.

This strategic guidance supports the planning of effective network deployments.

Assessments of
capacity supply

 

Receive detailed evaluations of available satellite capacitiy, based on accurate and realistic calculations of link budgets and interference effects.

Our simulations support the design of robust communication links and enable efficient capacity management.

Operations and
regulatory support

 

Let us guide you through the challenges of EPFD analysis, interference management and multi-system coexistence.

Our simulations ensure alignment with regulatory standards, while aiding the optimization of operational settings for maximum efficiency.

You may also be interested in

 

Space system design of satellite constellations for ESA

Modelling of satellite payload and system performance is a long-standing activity in our team. Work performed for ESA's Connectivity and Secure Communications (CSC) directorate expanded our portfolio into resource management and traffic routing.

 

Capacity study for German Bundesnetzagentur

In the context of adopting EU directive 2018/1972 on the Electronic Communication Code, Fraunhofer IIS was tasked by Bundesnetzagentur with performing a capacity study on existing and near-term satellite broadband infrastructure.

 

© iStock.com/monsitj

High throughput
satellite systems

Optimum efficiency in satellite communication

More Details