PocketSAT User Terminal Phase 3 Development

  • Status
  • Status date

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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click for larger image

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.


Key issues addressed in Phase 3 of the project include:

  1. 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.
  2. 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.

There are a number of portable satcom terminals available today that can provide regional or global packet data services. However, they are generally designed for portability rather than true mobility. With the growth in demand for mobile internet access and location-based services, we believe there are increasing market opportunities for miniature terminal types offering multi-media data rates and capabilities to users on the move.

Terminal manufacturers have had little motivation to strive for the degree of integration necessary to make such products possible, given the relatively low volumes of the mobile satcom market. This project aims to ‘seed’ the process by developing key technologies and components that can enable the required miniaturisation and thus remove barriers to entering this emerging market sector. With suitable equipment available in the marketplace, opportunities will follow for the development and deployment of location-based services comparable to those emerging for terrestrial 3G networks.

The outcomes of the work are potentially applicable to a wide range of satcom systems and service providers. Interest has been shown by a number of potential end-users, as well as satellite operators Inmarsat and SkyTerra.

The third phase of the project will see the construction of a complete operational IP-based satellite packet-data terminal for vehicular applications, designed for use with private networks operating over leased L-band satellite capacity. This product will fill a niche that exists in the market at this time, offering a price/performance combination not available with existing services.


A number of possible product configurations are possible using the PocketSAT building blocks. A hand-held terminal can be constructed using an omni-directional antenna, L-band RF module, and baseband processor module running satellite modem and protocol stack software.

The terminal will have integrated Bluetooth interface, GPS/Galileo receiver and battery/charger. It can be used as a clip-on accessory to a PDA or Smartphone to create a fully mobile hand-held data terminal with global IP connectivity.

The PocketSAT unit and host device can communicate wirelessly via Bluetooth. This allows the terminal unit to be detached from the host device and located up to tens of metres away from the user, giving a high degree of flexibility in operational configuration to support various static and mobile application scenarios. For example, the terminal could be placed on the deck of a yacht while the user browses the web below decks on a PDA. The same unit could later be taken ashore and used while travelling on foot or in a vehicle.

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An alternative configuration for vehicular applications involves mounting the antenna to the roof of the vehicle, and placing the electronics section inside the vehicle. The same omni antenna can be used, or replaced with a higher-gain tracking antenna. Under Phase 3 of the project, JAST are developing a low-profile antenna system for vehicular applications that uses a rotating platform that tracks in azimuth only.

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Latest-generation L-band satellite transponders are able to support data rates of many tens of kilobits per second to omni-class terminal types, and therefore support packet data services at rates comparable to terrestrial GPRS/UMTS services. Using the tracking antenna option, data rates can be increased to several hundred kilobits per second.


Phase 3 of the project will run from June 2008 to December 2009 and consist broadly of the following stages:

  1. Specification & Design – review of user requirements, finalisation of the architectural design, establishment of a test/validation plan.
  2. Implementation – detailed design of antenna and electronics hardware, and development/integration of modem/protocol stack software for a bespoke satcom packet-data air-interface.
  3. 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.

click for larger image

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.

    click for larger image

  • 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.

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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.

click for larger image
click for larger image


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.


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