Clarksburg, MD 20871
Tel: (301) 428-4000; FAX (301) 428-4600

Date Visited: May 10, 1997

WTEC: J.V. Evans (report author)



COMSAT Laboratories was formed in 1967 to assist in the successful development of the INTELSAT (intergovernmental organization) satellite system. Initially operating in temporary facilities in downtown Washington, DC the staff moved to their present building in 1969. In 1978 COMSAT Corporation ceased its role as technical manager of the INTELSAT system, and COMSAT was encouraged to engage in work for other parts of the Corporation, and outside.

During the period 1984 - 1992 COMSAT acted as systems engineer and contractor for the entire ground segment of the NASA Advanced Communications Satellite Program (an $80 million contract). Currently, COMSAT has a staff of about 220 and receives about half its annual budget (approximately $35 million) from internal customers and the balance externally through competitive bidding.

For much of its existence, COMSAT focused on satellite hardware, including all aspects of payload design and construction, and bus technology. In anticipation that future satellites would require multiple spot beams interconnected by an onboard (digital) processor, COMSAT worked on both of these technologies. Steerable transmit phased-arrays incorporating GaAs power amplifiers and phase shifters at C- and Ku-band were built as well as bulk demultiplexer/demodulators. Recently, however, the focus has shifted more towards supporting satellite applications (e.g., ATM over satellite) and quality-of-service issues.

COMSAT also has begun efforts at commercializing some of its technologies (through licensing the manufacture of several products), and is now actively selling various software tools. One of the licensed products is a "second generation" INTELSAT TDMA terminal that is being manufactured and sold by Aydin of Pennsylvania. A second is an MPEG 2 digital video compression system (transmitter called DVT 2000, and receiver DVR 2000) by Wegener of Atlanta, GA. Reflecting these changes COMSAT was reorganized early in 1997 into two principal divisions, (one dealing with technology development and one dealing with systems), and a small product development office was created.


COMSAT Laboratories is currently working on a number of research and development activities. A small sampling is indicated below. Research into the transmission of asynchronous transfer mode (ATM) via satellite has led to new product development. ATM offers a means for establishing a very flexible, seamless network. COMSAT Laboratories has developed patented techniques and products that allow ATM traffic to be carried reliably and efficiently over satellite at rates from 2.4 Kbps to 45 Mbps. When using the high quality, bandwidth-efficient capabilities of ATM, companies can significantly improve information flow between geographically dispersed locations, regardless of existing infrastructure. This information can even include corporate intranets, Internet access links and other advanced networks. Currently, tests are being conducted for operation of ATM traffic via satellite at rates of 155 Mbps.

Advanced very small aperture terminal (VSAT) systems are being developed at COMSAT Laboratories that allow efficient utilization of satellite bandwidth. The bandwidth on demand (BOD) systems utilize a time division multiple access (TDMA) technique for access to the satellite and will provide user connectivity options of ATM, Frame Relay, and ISDN to support future data communications requirements. With an ability to offer full mesh connectivity over a wide geographic area, BOD VSAT systems will provide users around the world with significant new connectivity solutions. COMSAT is presently engaged in the product development process with an eye to achieving both the technical requirements and a low recurring cost.

COMSAT Laboratories has completed the design and development of a new, low-cost 120 Mbps TDMA traffic terminal for the INTELSAT satellite system. Originally developed in the early 1980s, the INTELSAT TDMA Traffic Terminals required 13 racks of satellite equipment. COMSAT's new, low-cost terminal design utilizes the latest technologies to reduce the terminal to a single rack of communications equipment. The terminals are being brought to market in partnership with Aydin Telecommunications Corporation. These new TDMA Traffic terminals were recently installed at the AT&T earth station in Etam, West Virginia and were the first in this next generation TDMA system to carry live telecommunications traffic.

In a parallel effort, COMSAT Laboratories is completing development of the burst time plan software that is used to control the INTELSAT 120 Mbps TDMA network. With an overall understanding of the TDMA network, COMSAT has been able to create an easy-to-use system that incorporates a graphical user interface that will improve the efficiency and effectiveness of the TDMA network operations.

COMSAT Laboratories recently won a $14.4 million contract from Ericsson, Ltd. to develop a high-penetration, notification (HPN) subsystem for ICO Global Communications, Ltd., which is developing a handheld satellite phone service. This subsystem will alert ICO phone users to incoming calls even when they are not in the direct "line of sight" of the satellite. HPN subsystems will be located at each of ICO's 12 satellite access nodes (SANs), which will be linked together to form a single global mobile communications network called ICONET. The ICONET will be connected to the existing public telephone as well as cellular networks, allowing an ICO user to place and receive calls to and from anywhere on earth.

COMSAT Laboratories has developed the Nested Voice Codec algorithm for improved low bit rate voice communications, which will make it possible for users of portable telecommunications equipment to maintain connections even under degraded conditions. The Nested Voice Codec runs on a digital signal processing (DSP) chip. Benefits would include voice connections that can be maintained even under poor transmission channel conditions and receiver terminals that automatically adapt to channel degradation with no reverse control channel, providing an efficient use of bandwidth and a responsive, transparent adjustment.

COMSAT Laboratories has been awarded a contract from Inmarsat to develop, install and support equipment for the Aeronautical Network Channel Management System (NCMS). The system is intended to enable Inmarsat to serve a larger number of aeronautical customers simultaneously. This is made possible by dynamically allocating carrier frequencies among earth stations in response to demand. The NCMS equipment will be developed using commercially available hardware and software packages and customized software will be written to handle applications that are unique to the NCMS system. The contract includes two phases. Development of the NCMS was scheduled to take place in 1997. Worldwide installation, testing and qualification will occur in 1998 with service to commence in 1999.

COMSAT Laboratories has built and delivered three transportable in-orbit test (IOT) systems, the first transportable systems in the satellite industry, to Space Systems/Loral, a manufacturer of telecommunication satellites located in Palo Alto, California. The COMSAT Laboratories IOT systems provide fast and complete testing for new communications satellites that have been placed into orbit, making it possible for satellite operators to begin generating revenue and returns on their investments faster and with greater reliability.


COMSAT essentially now functions as a separate line-of-business within COMSAT with the requirement of making a profit. A number of products have been developed and licensed to manufacturers creating a royalty revenue stream, and the direct sale of several software tools that support satellite system design and operation is in progress.

Roughly half of the work of COMSAT is being undertaken for internal customers and the balance is secured through competitive bidding to outside entities. The focus of the work has shifted from satellite hardware to ground segment work that offers new services or improved quality of service.

Published: December 1998; WTEC Hyper-Librarian