Swift-Broadband Terminal for Spacecraft (SB-SAT)

Global Coverage – Near Real Time – On Demand – IP Based Communications

The Swift-Broadband Terminal for Spacecraft (SB-SAT) is a communications terminal designed for LEO applications that provides a bi-directional communications link to the LEO from the ground via the Inmarsat 4th Generation GEO Communications Satellite Constellation and the Inmarsat BGAN Network. SB-SAT provides near real-time communication access to the LEO satellite globally and without the need for dedicated groundstations or spectrum licenses.

The SB-SAT terminal together with the Inmarsat SB-SAT data service provides communications access to the SB-SAT equipped LEO satellite similar to the way in which the NASA TDRSS satellites do.

Using the constellation of existing Inmarsat GEO satellites as a relay, a spacecraft equipped with an SB-SAT terminal is accessible globally and in near-real time through Inmarsat’s BGAN network. Based on 3G technology, Inmarsat’s BGAN network provides IP connectivity to the SB-SAT terminal allowing the user to treat the SB-SAT equipped satellites as just another node on an IP network, either a closed one or the Internet.

Square Peg provides the BMS to Moog Broad Reach for incorporation into the SB-SAT UT that it is developing in partnership with COM DEV Europe and Inmarsat. The SB-SAT BMS incorporates several enhancements to cope with the unique characteristics of the SB-SAT environment, most importantly high Doppler which results in time-varying frequency offsets of up to +/- 44 kHz with a maximum rate-of-change of 55 Hz/sec as well as time-varying path delay with a maximum rate-of-change of 26 us/sec. The SB-SAT implementation is also challenging due to the processing constraints of space-qualified DSPs.

Key System Features


  • Uses Existing Inmarsat Communications Infrastructure
  • Global Coverage
  • Near Real-Time Access
  • Near Continuous Data Link
  • On-Demand Service Use
  • No Requirement for Frequency License
  • No Provisioning Delay – Stand-By Possible
  • Multiple Geographically Co-Located Links (Formation Flying)
  • Access from Anywhere On Earth via Internet/Inmarsat
  • Equipment Designed Specifically for Spacecraft Application

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