PAGE CONTENTS
Objectives
The objective of the project is the development of a miniature satellite communications user terminal platform known as ‘PocketSAT’. This platform is aimed at L-band mobile satcom services, including hand-held, land-mobile and maritime. The technologies and components developed for PocketSAT are also intended for wider commercialisation as potential building-blocks for a variety of mobile satcom terminal products.
Phase 1 of the project (completed 2004) saw the development of a proof-of-concept hardware/software platform, including an L-band RF module developed by partner company Giastar Ltd.
Phase 2 (completed 2006) built on the achievements of Phase 1 and produced a fully-integrated L-band terminal, including powerful DSP-based baseband processor board with embedded physical layer and protocol stack software, and a high-efficiency L-band omni-directional antenna. The focus was on components suitable to construct an omni-class terminal for Inmarsat’s BGAN service.
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Phase 3 (due to complete in 2009) is extending the PocketSAT developments in another direction that will allow the partners to pursue an additional commercialisation opportunity: private packet-data networks operating over leased satellite capacity. A second-generation L-band RF module is being developed by partner IICT. An intermediate-gain tracking antenna is being developed by partner JAST to provide a higher-gain alternative to the omni antenna developed under Phase 2.
Working with Skymira LLC, US-based commercial partner, ComSine is developing a bespoke all-IP packet-based air-interface that will allow thousands of users to efficiently share common forward and return satellite channels.
ComSine is also developing new physical layer and protocol stack software compliant with this air-interface to run on the PocketSAT hardware platform. The Phase 3 activities will culminate with a series of field-trials conducted over L-band capacity on a North American MSAT satellite. MSAT air-time has generously been offered free by SkyTerra for the trials.
Challenges
Key issues addressed in Phase 3 of the project include:
- Air-interface validation – this will be the first implementation of the complex TDMA-based air-interface that ComSine is developing with its US commercial partner, Skymira. There are technical risks associated with such a complex software task, particularly when the air-interface design is still unproven. An ‘inverse terminal’ platform will also be developed, initially to support terminal validation activities, then later upgraded for use as a channel unit in gateway Earth stations.
- Design for manufacture – the partners face considerable challenges in developing antenna and RF subsystems that are fully compliant with the demanding the air-interface specifications, while at the same time being inexpensive to manufacture.
Plan
Phase 3 of the project will run from June 2008 to December 2009 and consist broadly of the following stages:
- Specification & Design – review of user requirements, finalisation of the architectural design, establishment of a test/validation plan.
- Implementation – detailed design of antenna and electronics hardware, and development/integration of modem/protocol stack software for a bespoke satcom packet-data air-interface.
- Tests & Demonstrations – validation and demonstration of the integrated L-band terminal in the laboratory and via over-satellite field-trials using a SkyTerra MSAT satellite.
Current Status
Phase 1 of the project (completed 2004) saw the development of a proof-of-concept hardware/software platform, including an L-band RF module developed by partner company Giastar Ltd.
Phase 2 (completed 2006) built on the achievements of Phase 1 and produced the following key components:
- A powerful, flexible DSP-based baseband processor board capable of hosting complex physical layer and protocol stack software. Includes a Bluetooth interface and SIM-card reader.
- A suite of physical layer (modem) software functions. These functions may be used to implement, for example, the forward and return bearers for an omni-class Inmarsat BGAN terminal.
- A compact, low-cost, high-efficiency, near-omni-directional antenna meeting the requirements for a man-portable omni-class terminal product.
GateHouse A/S successfully ported their core-BGAN protocol stack to the PocketSAT platform – the most compact and low-power platform to yet host this stack.
Also produced was an item of bespoke test equipment known as the ‘LES Converter Unit’ that serves as an ‘inverse terminal’, allowing end-to-end testing at L-band in the laboratory.
The Phase 2 baseband hardware/software and omni antenna may be integrated with the Phase 1 RF hardware to create a complete L-band terminal.
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Update May 2010
- Phase 3 project commenced in June 2008.
- Progress Meeting #1 held October 2008.
- Specification & Design stage completed and documented.
- Baseline Design Review held January 2009.
- Progress Meeting #2 held September 2009.
- Implementation stage completed and documented.
- Mid-Term Review held March 2010.
- The System Integration & Test stage is awaiting authorisation from ESA before it officially proceeds. However, some integration activities have already commenced. All partners convened in Switzerland for an Integration Workshop in March 2010.
- The tracking antenna assembly and integrated baseband / RF electronics unit are pictured below.
