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