PowerPoint PresentationFly-Over Terabyte Offload (FOTO) -
Conceptual Development -
Dr. Michael Thomason Systems Engineer IV Bevilacqua Research Corp.
S&T/SET FSO POC Edwards AFB, CA
FOTO Concept Development Overview Outline
• Edwards AFB Background and Information
• Review of FOTO Concept and History
• The NRL/EAFB Proposed FOTO Program
• The DoD SAR&D Funding Approval
• FSO Technology Status
Air Force Test Center (AFTC) 412th Test Wing
• The mission of the 412th Test Wing of the Air Force Test Center
(AFTC) – Conduct Air Force verification of contractual performance
requirements for
aircraft systems under test (SUT). – Flight testing of an SUT
entails an intense period of Air Force/Supplier test
operations at Combined Test Force (CTF) organizations at Edwards. •
Flight Test Data
– Testing of modern military aircraft can produce terabytes of
crucial data per sortie.
– Only a small fraction of the data can be telemetered down to the
control center in real time due to radio frequency (RF) bandwidth
limitations in available L, S and C bands.
– Available spectrum has decreased due to commercial selloff by the
FCC. – State-of-the-art on-board data recorders capture all the
aircraft data, but data
is normally only available for post mission analysis. • The
Problem
Aerial Concept of Edwards AFB 412th TW Range
Semiarid, flat part of CA, beside dry lake beds, with mostly sunny,
cloud free days – perfect for flight testing.
Background: Support for SUT Flight Test - Typical Scenario
Today-
1) Aircraft Instrumentation • Team loads dozens of sensors, cabling
, and electronics on SUT – many dozens of data channels • Also
telemetry transmitter, amplifier, and antennas • On-board solid
state data recorder - 200 Mbps recording rate - 1 TB recorder
capacity
2) Real Time Serial Streaming Telemetry (SST) • Downlinks a small
fraction of recorder data • L-, S-, or C-Band downlink carrier ;
modulation bandwidth 3 – 20 Mbps • Ground stations receive SST via
large parabolic reflector antennas • Data transported via ground
fiber network to control center • Range personnel and test
engineers man data terminals
3) Flight data Analysis • Real-time monitoring of downlinked data
with minimal analysis • Post mission - retrieve, deliver, archive
recorder data • Support mission debrief • In-depth analysis by
analysts for detailed results
Flight Test Need: Provide New (Green) Mission Data Recorder Options
and Flexibility
Flight Test Data Review
Decision Making)
Room)
Drive)
Extend Mission Data Capacity
TB Downloads in Minutes
Off-load Filled Recorders to
Continue Mission
More efficient flight test operations could result from more
expedient data delivery.
The Fly-Over Terabyte Offload (FOTO) Concept
• 412th TW Need: Filling data recorders • Recommended Solution:
Develop and evaluate a prototype air-to-
ground optical link capable of operating in burst mode to downlink
large volumes of data between test points during test
operation.
• Free Space Optics (FSO) communications technology is at a point
that very high speed data rates are available to download
essentially error free data volumes with modern forward-error-
correction (FEC), packet/frame retransmission and
interleaving.
• Fiber Optics comm routinely delivers data well above the rates
FOTO needs
• There are five Alternative Configurations under consideration
which fall into three categories: 1) Air-to-Ground, 2)
Ground-to-Ground, and 3) Air-to-Air.
Air-to-Ground Configuration Alternative 1: Straight Flight Path of
System
Under Test (SUT) Fly-Over FSO Download
The near-overhead, high data rate FSO allows terabyte capacity
downloads over very modest fly-over ranges.
Air-to-Ground Configuration Alternative 2: Circular Flight Path of
SUT
Fly-Over FSO Download
The circular flight path provides constant range, a single line-
of-sight (LOS) angle, and additional download time
flexibility.
Ground-to-Ground Configuration Alternative 3 – Post-Mission
Landing-Gear “LiFi”
LiFi (light fidelity) is the proposed, futuristic LED equivalent of
WiFi. LiFi is something of a misnomer for the taxiway data-offload
mission but captures the innovative spirit of Alternative 3 for the
FOTO Program.
Air-to-Air Configurations Alternative 4 - Refueling Optical
Terabyte Offload (ROTO)
The FSO architecture afforded by the refueling optical terabyte
offload (ROTO) scenario enables SUT refuel downloads along with
simultaneous onboard recorder data uploads.
Air-to-Air Configurations Alternative 5 – Side-by-Side,
Air-to-Air
Download
The side-by-side scenario could provide ideal FSO conditions to
quickly empty onboard recorders, potentially with data transfers at
extremely high bit rates.
Proposed Circular Flightpath Download CONOPS and Analysis
• Initial analysis of alternatives is complete.
• The tightly circular, overhead flightpath is has been chosen as
the alternative to support requirements analysis.
• For a high performance military aircraft a reasonable geometry
could be achieved by an aircraft at 10,000 feet executing a 1-G
turn at Mach 1/3.
• The geometry and variables are shown in the figure to the right
with the top-view of the circular path on the left and side-view to
the right.
Circular flight Path IOC FOTO Mission Needs
Flight Parameter
Parameter Value
Common Units
SI Value
SI Units
Altitude 10 kft 3.0 km Speed 1/3 Mach 110 m/s
Radial Acceleration 1 g 9.8 m/s/s Circle Radius 0.77 mi 1.2 km
Zenith Angle 22 deg 0.39 radians Slant Range 2.0 mi 3.3 km
Time/circle 1.2 min 70 sec
Data Volume 1 TB 8.0E+12 bits 1 Circle Bit Rate Req'd 113 Gbps
1.1E+11 bps 3 Circle Bit Rate Req'd 38 Gbps 3.8E+10 bps
Latency No Requirement Post FEC Quality Error Free
Laser Eye Safety (1.55μm) Eye Safe at Window
These results and rates are not FOTO Program requirements, but the
short ranges, high elevation angle, and latency allowance make
rapid download
feasible.
Sheet1
Flight Parameter
Parameter Value
Common Units
SI Value
SI Units
113
Gbps
38
Gbps
NRL Managed: Free-space Optical Telemetry Offload (FOTO)
SAR&D Funding Source - Industry Day – June 2016 Request for
Proposals – Scheduled for 2018
• Technical Program Manager Dr. Linda M. Thomas - US Naval Research
Laboratory
• FOTO Air Force Team DoD Test Resource Management Center &
Edwards AFB 412thTest Wing –T&E Test Range experience for
identification of AF customer needs, and
transition management
• Naval Research Laboratory Technical subject matter expertise, FSO
link validation, I&T platform coordination and test
planning/execution
Contractor awardee will develop the FOTO technology and system to
meet the mission needs.
Mission 1: In Flight Offload (IFO)
Industry Day: FOTO objective was to develop a field testable
prototype for an air-to- ground telemetry offload system using
compact and affordable FSO terminal solutions.
Mission 2: Opportunistic Offload/Upload (O2U)
Enable the streaming of selective data to the ground for quick-
look checks at low complexity ground nodes.
Additional Technical Information
Typical Commercial Grnd-to-Grnd FSO/Fiber System
(LaserOptronics)
Today commercial FSO enables optical transmission at speeds of up
to 2.5 Gbps and in the future 10 Gbps using WDM (Wavelength
Division Multiplexing).
MIT/LL Air-to-Ground Demo at 2.6 Gbps
(Walthers, et al. MIT Report, 2010 ---- George Nowak, Group
Leader)
Error Correction
Forward Error Correction (FEC) inserts additional symbols so that
all data can be recovered if some symbols are lost due to fading By
itself, FEC is ineffective against millisecond-class fades at high
channel rates (frame < 50 μs). Interleaving spreads symbols in
time, allowing FEC to operate in fading channel.
Spatial Diversity
Intra-Aperture Spatial Diversity: combine signals from four (or
more) receiver mini-apertures (with diameters less than r0) to
reduce atmospheric degradation.
FSO/Fiber Optics State-of-the-Art Data Rates - Typical Example from
2016 -
• Investigation and Demonstration of High Speed Full-Optical Hybrid
FSO/Fiber Communication System Under Light Sand Storm Condition
(100 meter link)
• Department of Electrical Engineering, King Saud University,
Riyadh, 11421, Saudi Arabia
• DOI: 10.1109/JPHOT.2016.2641741_1943-0655 © 2016 IEEE
reconfigurable/flexible transmitter. Work
modulation format (32-QAM) with 18
Gbaud symbol rate. The achieved BER was
under the FEC limit; hence, error free
transmission is possible using proper
coding.
Concluding Remarks
• Our conclusion, regarding FSO technology, is the state-of-the-
art can likely support the high data rates needed for the rapid
data offloads proposed by FOTO.
• But FOTO remains a technology development effort.
• Before IOC, there are other obstacles such as low cost, low SWaP,
higher recorder offload speeds.
• However the FOTO team believes the high data rate demonstration
is the key first step to be achieved before further
development.
Slide Number 1
Air Force Test Center (AFTC) 412th Test Wing
Aerial Concept of Edwards AFB 412th TW Range
Background: Support for SUT Flight Test - Typical Scenario
Today-
Flight Test Need: Provide New (Green) Mission Data Recorder Options
and Flexibility
The Fly-Over Terabyte Offload (FOTO) Concept
Air-to-Ground ConfigurationAlternative 1: Straight Flight Path of
System Under Test (SUT) Fly-Over FSO Download
Air-to-Ground ConfigurationAlternative 2: Circular Flight Path of
SUT Fly-Over FSO Download
Ground-to-Ground ConfigurationAlternative 3 – Post-Mission
Landing-Gear “LiFi”
Air-to-Air ConfigurationsAlternative 4 - Refueling Optical Terabyte
Offload (ROTO)
Air-to-Air ConfigurationsAlternative 5 – Side-by-Side, Air-to-Air
Download
Proposed Circular Flightpath Download CONOPS and Analysis
Circular flight Path IOC FOTO Mission Needs
NRL Managed:Free-space Optical Telemetry Offload (FOTO)SAR&D
Funding Source - Industry Day – June 2016Request for Proposals –
Scheduled for 2018
Mission 1: In Flight Offload(IFO)
Mission 2: Opportunistic Offload/Upload (O2U)
Additional Technical Information
Typical Commercial Grnd-to-Grnd FSO/Fiber System
(LaserOptronics)
MIT/LL Air-to-Ground Demo at 2.6 Gbps (Walthers, et al. MIT Report,
2010 ---- George Nowak, Group Leader)
FSO/Fiber Optics State-of-the-Art Data Rates- Typical Example from
2016 -
Concluding Remarks
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