Executive Summary
Welcome to Satcom series 1 – in this blog we will emphasize on basic understanding of satellite communication – spectrum allocation , types of satellite service is in offer today, satellite coordinate systems and ground station.
Following are the categories the blog has been segregated –
Satellite coverage and services
spectrum and its allocation
High level satellite function and how it works
High level Ground station systems :Threat surface and cloud adoption
Satellite coverage and services
Traditional satellite can be imagined as a repeater, it receives signal form ground station/user terminal, typically shift phase and retransmit signal to gateway system in ground station – transmitting radio signal is called uplink and retransmitting back to ground is caled downlink frequency and both are differnt frequrency in nature.
Based on the coverage – we can define as follows
- Geo Sat with no frequency re-use and covers large areas(continent).
- High Throughput Satellite
- Mega satellite network with inter connected satellite communication
Fig 1 Geo satellite and its coverage
Fig 2 HTS satellite networks – blue beams are identified as frequency reuse can be imagined as mobile cell in space.
Fig 3 Maga satellite networks -satellite broadband intenet
Spectrum and its allocation
What is spectrum – any device that communicates wirelessly needs spectrum – these include car, monitors, wireless devices and satellites.
Fig 4 Foundation model for Frequency allocation and use
L-band (1–2 GHz) – Typical uses: GPS navigation, satellite phones (e.g., Inmarsat, Iridium), aviation tracking, and maritime communications.
S-Band (2–4 GHz) Typical uses: Telemetry, tracking and control (TT&C), mobile satellite communications, S-band payloads for aviation and rail safety, and multimedia delivery to handheld terminals. It also supports deep space missions like the James Webb Space Telescope, which uses S-band for real-time telemetry.
C-band (4–8 GHz) Typical uses: Satellite TV broadcasting, enterprise VSAT networks, long-distance telephony, and disaster recovery communications
X-band (8–12 GHz) Typical uses: Military satellite communications (MILSATCOM), radar imaging (SAR), battlefield data relay, and government TT&C
Ku-band (12–18 GHz)Typical uses: Satellite television (DTH), in-flight connectivity, maritime broadband, and commercial VSAT services.
K-band (18-26 GHz)Typical uses: law enforcement radars, collision avoidance systems in cars and surface movement radars for aircrafts and vehicles on airport’ ground.
Ka-band (26–40 GHz)Typical uses: High-Throughput Satellite (HTS) internet, satellite-based 5G backhaul, cloud access, military communications, and enterprise broadband.
Fig 5 : Frequency in use for satcom – ofcom data
High level satellite function and how it works
Components of satellite
Typically satellite has following components defined as simplified High level view.
- Platform ( is the foundational structure and service module of a satellite that provides essential infrastructure for its mission. It contains systems for power generation, communications, thermal control, navigation )
- Payload (The primary mission equipment of the satellite -Imaging sensors,relaying signals, Scientific instruments )
Communication System
- Enables data exchange between the satellite and ground stations – can be referred as uplink and downlink frequencies subsequently.
- antennas, transmitters, receivers
Power System
- Solar panels convert sunlight into electricity.
- Batteries store energy for use during eclipse periods.
Thermal Control System
- Maintains temperature using radiators, heat pipes, and insulation.
Satellite Operation (ground and mission control)
- Launch & Deployment: Satellite is launched into orbit by a launch vehicle.
- Orbit Insertion: Satellite reaches operational orbit (LEO, MEO, GEO, etc.).
- Data Transmission and command: Communication system sends/receive data to/from ground stations.
- Orbit Maintenance: Thrusters perform station-keeping or orbit adjustments.
- Health Monitoring: Telemetry data is monitored for satellite status and health.
Satellite location and coordinate systems
To model satellite information in system for simulation and testing – we must have corodinate systems to measure specific information and its orbit calculation.
GNSS – global navigation system that can identify any device in earth, where we are.
Following are the list of provider of Global Satellite signals
- GPS USA
- GLONASS Russia
- Galileo EU
- BeiDou China
How to define satellite location in space – there are two popular satellite coordinate system is used for modelling/simulation
- Earth-Cantered, Earth-fixed coordinate system (ECEF) use : when we use GNSS coordinate – this is described as earth location or ground station location
- Earth-Cantered Inertial (ECI) use: The ECI system is useful for analyzing and predicting the orbits of objects in an inertial space framework.
link for details info on coordinate system
Satellite orbit types – GEO (~ stationary with respsect to earth ,altitude ~36000 km) , MEO ( not synchronized with earth roation ,altitude ~ 5500 -12000 km ) LEO (not synchronized with earth rotation,altitude ~500 -900 km)
High level Ground station systems :Threat surface and cloud adoption
To earth station – let’s first visualize antena evolution and it provides geometric intuition before moving into earth station architecture.
Antenna Evolution
Fig 6 :
For visualization – C band antena 30 meters antena
Conceptual High Level View of Ground station for Broadband GEO satellite
Following are the simplified conceptual diagram of a vsat ground station – vsat satellite operates on geo orbit – it can enable broadband operation to in remote place – for simplificity we only cover necessary componets in block diagram.
fig 7 : Simplified high level view of ground staion gateway and borbad staellite pop in a star topology
Threat Surface
Network Resource and communication medium
- Radio Access Link
- Node or domain communication security
- Inter satellite communication (will be covered in upcoming blog)
User and application security
- User authentication/authorization to services
- Authorized Services accessibility for User and SBA domain communication
- Configuration and visibility shared responsibility of user and CSP
Conecptual Inter satellite communication: ground sation on cloud GSaaS and network slice.
The following are the highlights of the architeture
- Inter satellite communication (GEO and LEO)
- Multi Access Edge to facilitate on LEO earth station (there could be many use cases, we have covered simpified LEO,GEO and earth station communication for bordband operation
- GSaaS – Ground station as a service
- Operation/data bandwidth specific slice for GSaaS operation
- DU and CU can be defined as part of GSaaS – DU is a cloud unit within Multi access network in Telco/hyperscaler and CU or central cloud unit can be defined as core/central unit with Telco for slice managment.
- Threat surface as covers in 5G security model for RU-DU-CU as assumed same for GSaaS
- We have already covered attack surface information in our previous blog –security viewpoint
Fig 8 : Multi access Edge Slice and Ground station as a service on cloud, network slice could be the good option to use in future for bandwidth centric/use case specific operation as a integrated part within Multi Access Edge
Conclusion
We have covered what and why space of satellite overview, coverage and its operation in ground station- different type of satellite networks and its orbit and simplified ground station view,
It is an opportunities for Telco industry to introduce and manage multi access edge near to ground station enabling network slice on demand – moreover software defined radio and inter satellite communication in LEO orbit can be used as a repeater for GEO/MEO satellite, Hence reduce latency and abstracting legacy operation – but there could be many use cases that might require legacy system to work AS IS or combination of private cloud/public cloud adoption more application modernization.
GSaaS Slice can be a good option for bandwidth centric specific operation – moreover edge facilities to ground station also provides private network and reduce the chance of attack surface. – It also provide the satellite ground station for modernization and can be used private/public cloud as per their choice.
upcoming blog(s)
Orbit, modulation techniques, Encryption ,security viewpoint, 5G and NTN,link budget
Happy learning !
Live Satellite link
https://satellitemap.space/vis/constellation/oneweb#
Ref Link
https://www.esa.int/Applications/Connectivity_and_Secure_Communications/Satellite_frequency_bands
https://www.sciencedirect.com/topics/engineering/geosynchronous-orbit
https://www.nasa.gov/smallsat-institute/sst-soa/ground-data-systems-and-mission-operations
https://en.wikipedia.org/wiki/KA-SAT#/media/File:KA-SAT_spot_beams_coverage.jpg
https://www.mathworks.com/help/aeroblks/coordinate-systems-for-modeling.html
