News Archive
Milestone NRL/NASA Experiment Demonstrates Unprecedented
Data Transmission Rates
Janice Shultz
Public Affairs,
Naval Research Laboratory
This article first appeared in the December 21, 1998 issue
of Labstracts, Naval Research Laboratory
During a record-breaking demonstration of a Ka-band, two-way
satellite communications link, scientists from NRL, Glenn
Research Center, and their industry partners achieved an unparalleled
data rate transmission of 45 megabits per second (Mbps) between
a moving vessel at sea and a fixed Earth station. Previously,
the highest demonstrated ship-to-shore satellite data rate
was 2 Mbps.
A series of tests conducted in October on southern Lake Michigan,
near Chicago, using NASA’s Advanced Communications Satellite
(ACTS), clearly illustrate the viability of high data rate
(HDR) Ka-band systems for ship-to-shore communications. High
data rates will open new applications for both Navy communications
and civilian users of mobile satellite systems and services.
Using current technology, the Navy cannot link HDR shipboard
local area networks (LANS) to terrestrial networks at comparable
HDR speeds while ships are away from port. NRL now has programs
underway to develop and demonstrate techniques to enable HDR
wide area network satellite and wireless connectivity from
ships, and HDR satellite communications are a critical component
of many of these programs. The objectives of this experiment
focused directly on significant elements of HDR mobile networking,
in this particular case ship-to-shore, that address this current
DoD requirement.
Ultimately, small-deck combatants such as destroyers and
frigates outfitted with similar equipment could benefit from
the same meteorological and oceanographic data currently received
by carriers, cruisers, and other large-deck combatants. The
faster data transmission rate will also permit small-deck
vessels to receive teletraining along with their large-deck
counterparts and make teleconferencing technology available
for interactive planning, crisis management, and telemedicine.
The NRL-NASA Shipboard ACTS Ka-band Experiment (SHAKE) provided
at least 20 times greater data rate than the current shipboard
standard, demonstrating data rates of 45 Mbps and user applications
(file transfers, video teleconferencing) data rates of above
40 Mbps, significantly higher than the current 1.5 Mbps of
64 Kbps standards. While future Navy systems may not require
45 Mbps to a single platform, it is likely data rates in the
1-2 Mbps range, with the ability to increase as required,
will be required on a larger number of ships and combatants
than is currently available today.
The NRL and NASA SHAKE researchers conducted other experiments
concurrently with the data rate transmission trials, including:
- TCP/IP file transfers, which would permit the high speed
transfer of imagery, strategic and tactical theater information
to and from Navy ships. This data transfer technique is
also applicable to a host of NASA spacecraft in near-Earth
orbit that routinely transmit data from space to ground
using Geostationary relay satellites. Data transfer tests
were conducted in disk-to-disk, disk-to-tape, and tape-to-disk
configurations
- Video and voice technologies for real-time video and voice
delivery. These technologies can be used for video conferencing,
crisis response, telemedicine, mentoring, education, telephony,
and entertainment
- Tracking performance testing of the current system in
a Ka-band with the satellite in an inclined-orbit environment
was evaluated
The final goal of this work, says NRL principal investigator
Mr. Mike Rupar, is to support the use and understanding of
emerging Ka-band satellites and services to fulfill emerging
HDR Naval satellite based networking requirements.
Understanding how emerging satellite services can best be
used to meet Naval requirements and how the Navy can best
be positioned to use these emerging services is a critical
component of this work. Underlying networking, protocol, terminal,
and bandwidth-on-demand issues, combined with variable bit
rate service and HDR capabilities, present challenges not
typically addressed in current Naval SATCOM systems, notes
Rupar.
Mr. Louis R. Ignaczak, Chief, ACTS Experiments office notes,
"With today’s pressure of shrinking resources, rapid
advancements in technology, and the pursuit of relevant communication
architectures for one’s mission, it is becoming extremely
important to collaborate on synergistic endeavors and leverage
unique opportunities - it seems to be a natural fit for NASA
and NRL to jointly promote technology that benefits the Nation
as a whole."
Supported by the Office of Naval Research, participating
industry organizations included: Infinite Global Infrastructures,
Chicago, Illinois; Sea-Tel, Inc., Concord, California; Hill
Mechanical Group, Chicago; FORE Systems, Pittsburgh, Pennsylvania;
Xicom Technologies, Santa Clara, California; Raytheon Marine
Company, Manchester, New Hampshire; and Comsat Laboratories,
Clarksburg, Maryland. Additional information can be obtained
at: http://mrpink.grc.nasa.gov/shipboard.
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