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SB-SAT Protocol Stack

The GateHouse SB-SAT Protocol Stack for Low-Earth Orbit (LEO) Satellites is a low risk alternative to a key component in development of an SB-SAT modem. SB-SAT modems gives you better connectivity for your LEO Satellite and thereby optimises the use of the LEO satellite and the applications that runs with the satellite. i.e. you can rely on other satellite systems for the relay of generated data.

The GateHouse SB-SAT protocol stack is software for use in SB-SAT modems. By using a proven protocol stack, significant savings can be realised in terms of both time and money. Furthermore, it reduces risk in the development process of an SB-SAT modem.

The SB-SAT Protocol Stack is a mobile device protocol stack for use on Low-Earth Orbit Satellites (LEO), and in combination with Inmarsat’s I4 network of GEO-stationary satellites it enables global and continuous connectivity to LEO satellites. IP connectivity from LEO spacecrafts provide low-cost access to real-time command, control and telemetry with bandwidth up to 492 kbit/sec. Coverage is practically global at low LEO orbits while remaining fairly close to global at higher orbits. This provides satellite operators access to their satellites from anywhere.

The GateHouse SB-SAT protocol stack is an adaption of the market-proven BGAN Protocol Stack which has been deployed in more than 100,000 end-user terminals for land, maritime and aeronautical uses. SB-SAT is based on the aeronautical terminal classes and provides additional features for use in low-earth orbit:


  • IP connectivity up to 492 kbit/s
  • Antenna pointing
  • Beam handover and satellite switching
  • Predictive handover at spot-beam boundaries
  • Accurate return link burst timing based on orbit extrapolation
  • Predictive Doppler compensation


The protocol stack is fully conformance tested using Inmarsat test requirements and is validated using full-orbit simulation using the GateHouse BGAN Network Emulator. The capabilities of the emulator allow set up of realistic orbits with full simulation of beam-to-beam handovers and satellite switches.

Have any questions?

Contact me on +45 9932 4086 for more information or to set up a meeting.
- Thomas S. Jensen