Trends in Aeronautical Flight Test Telemetry
Timothy Chalfant & Gerhard MayerEdwards AFB ICTS
The International Consortium for Telemetry Spectrum
International Seminar AeroIndia 2009 BangaloreApproved for Public Release Case AFFTC-08334
Distribution A: Distribution is unlimited
Agenda
1. General Trends (G. Mayer)
– The Spectrum Problem– The Role of the ICTS– WRC´07 Resolutions
2. Future Trends in FT Telemetry (T.Chalfant)
– Flight Test Telemetry in C –Band– Network Topologies– Telemetry Standards
3. Summary and Conclusions
General Trends in flight test telemetry
• More measured parameters per missione.g. 3000 (AB 300), >30 000 (AB 380)
• Higher amplitude & time resolution8b & 10us (1970), 32b & 100 ns (2008)
• From PCM to packetized transmissionprotocol overhead !
• Leading to increased data rates100 kbps (1970) , 40 Mbps (2008)
• More frequency spectrum required !
Flight tests in civil aviationincrease of measured parameters
27
Heim Systems GmbH
Airbus
The spectrum problem
• Spectrum allocated for flight testing (1400 to 2450 MHz) has been outstripped by an exponential growth in required measurements and data rates
• The existing telemetry bands are increasingly affected by encroachment from commercial interests and have been reduced internationally
• Interference from unlicenced wireless devices has impacted the use of the remaining spectrum
Telemetry Spectrum -demand increasing but supply decreasing
10
100
1,000
10,000
100,000
1970 1975 1980 1985 1990 1995 2000 2005 2010 Year
F - 22 AIM - 9X
F - 15
10
100
1,000
10,000
100,000
1970 1975 1980 1985 1990 1995 2000 2005 2010 Year
F - 2 AIM - 9X
F - 15 Kbps
To Ensure the Future Availability of Electromagnetic Spectrum
for Telemetering
International Consortium for Telemetry Spectrum
The ICTS is an international advocacy group of telemetry practitioners committed to promoting the benefits of electromagnetic spectrum for telemetering applications.
ICTS
• Is a sponsored group of the International Foundation for Telemetering (IFT) – a not-for-profit organisation that hosts the annual Int. Telemetering Conference.
• Comprises membership from Government, Industry, and Academia across the ITU regions
• Is organised (mirroring the three ITU regions) for a regional co-ordination and communication/ networking (mainly using e-communication methods)
• Under the rules of its IFT charter, the ICTS has no“official position” on spectrum requirements in the context of the WRC
Main ObjectivesIn this endeavor, the main objectives of the ICTS are:
• Create a forum for information exchange on potential telemetry spectrum issues,
• inform national, regional, and international spectrum managers of the importance of telemetry to their economy and security and
• inform and invite open participation in the group to all telemetry practitioners; including government; industry, academia, etc. and share information on the use, research, and development of new technologies for improving the use of telemetry spectrum.
Situation just before WRC 2007• 5 additional bands for AMT were under study of
AI 1.5 (4.4 to 6.7GHz). All bands are considered to have other users (existing occupants).
• The CPM was the primary decision basis for delegates, commenting on advantages / disadvantages, on basis of compatibility and technical studies discussed at the WP8B.
• ICTS information booth during the WRC 2007, to show the importance of AI 1.5 to the delegates and
decision makers of ALL nations.
REGION
1
Europe
Africa
Documents : 305 (COM 4),
335 (Plenary) ; 336 (Plenary)
4400
MH
z
4940
MH
z
6700
MH
z
5925
MH
z
Except Brazil, Cuba,
French overseas depts,
Guatemala, Paraguay,
Uruguay, Venezuela50
30 M
Hz
5091
MH
z
5150
MH
z
5250
MH
z
Documents : 305 (COM 4),
Except in Algeria, Saudi Arabia,
Bahrain, Egypt, United Arab Emirates,
Jordan, Kuwait, Lebanon, Morocco,
Oman, Qatar, Syrian Arab Republic,
Sudan, Tunisia
REGION
2
America
REGION
3
Asia&Pac
Brasil
Except
Brasil, ,Cuba,
French overseas
deptmts
Australia
NOT
ALLOCATED
NOT
ALLOCATED
NOT
ALLOCATED
NOT
ALLOCATED
NOT
ALLOCATED
NOT
ALLOCATED
Documents : 305 (COM 4), 335
(Plenary) ; 336 (Plenary)
2. Future Trends in Flight Test Telemetry
• C-Band Telemetry Operation
• Network Topologies
• Telemetry Standards
Flight Test Telemetry in C-Band• Link budget comparing C- to S-Band
fc = 5170 MHz, λC = 5,8 cm; fS = 2320 MHz, λS = 13 cm
free space attenuation increase, Δα ~ (λS/λC)² -7dBgnd antenna* gain can compensate, GR ~(λC/λS)² +7dBaperture angle of gnd antenna,* ~ λC/λS βc = 0,45 x βs
flight antenna, wide area coverage identical gain 0dB
• Influence weather & environmentadditional Atmospheric loss in wet regions (40° lat.) -3dB
less gnd reflections expected at low elevation angleshigher “roughness” of terrain, proportional λs/λc, generates diffuse refraction patterns instead reflections.
* same effective antenna area for C-and S-Band assumed
CTEIP topics related to C-band Implementation
• Multi-mode, multi-band transmitters & control interfaces• TM receiver changes required• Multi-carrier, single-carrier waveforms• Implementation of FEC and LDPC• TM platform integration issues with C-band• Integration into spectrum management systems• Ob & Gnd multiband antennae systems• Using & adaption existing tracking algorithms
iNET multi-band gnd receiving antenna concept
C-BAND FEED
SST4400-4940 MHz5091-5150 MHz
L/S-BAND FEEDTMNS Network1755-1850 MHz
SST1435-1525 MHz2200-2400 MHz
BAND PASS FILTER
4400-4940 MHz5091-5150 MHz
VH
HYBRID 90o
BAND PASS FILTER
4400-4940 MHz5091-5150 MHz
LOW NOISE AMPLIFIER
35db
LOW NOISE AMPLIFIER
35db
ATTENUATOR 6db
ATTENUATOR 6db
RF MIXER
POWER DIVIDER
REFERENCE OSCILLATOR
3720 MHz
RF MIXER
ATTENUATOR 3db
ATTENUATOR 3db
BAND PASS FILTER
680-1430 MHz
BAND PASS FILTER
680-1430 MHz
DRIVER14db
DRIVER14db
TRIPLEXER
VH
HYBRID 90o
TRIPLEXER
LH/RH SELECTION
SWITCH
LOW NOISE AMPLIFIER
35db
LOW NOISE AMPLIFIER
35db
ROTARY JOINT
I/O PANEL
POWER DIVIDER
POWER DIVIDER
BAND PASS FILTER
630-1430 MHz
ANTENNA SYSTEM
RHCP
LHCP
IEEE 802.3
BI DIRECTIONAL AMPLIFIER
30db
TMNS TRANSCEIVER
BAND PASS FILTER
630-1430 MHz
DRIVER14db
DRIVER14db
ATTENUATOR 6db
ATTENUATOR 6db
RF MIXER RF MIXER
POWER DIVIDER
REFERENCE OSCILLATORS
1035 MHz1245 MHz1525 MHz
ATTENUATOR 3db
ATTENUATOR 3db
BAND PASS FILTER
1695-2485 MHz
BAND PASS FILTER
1695-2485 MHz
C-BANDLHCP
C-BANDRHCP
GROUND STATION
Immediate Development & Testing Efforts
• C-Band Hardware
airborne FM/PCM transmitters available
IRIG 106 Standard multimode transmitters in developmt
Retrofit gnd antennae, down convert signals
US DoD project already supported initial flight trials
• Operational Aspects
Tracking systems & algorithms need up front evaluation
Initial flight trials show no channel anomalies
17
Network Telemetry Topology
The iNET Project
• Preserve existing TM link for safety of life / flight
• Make Bi-directional wireless network connection to TAs:– Dynamic bandwidth
(spectrum) sharing based upon priority and quality of service
– Improved transmission quality (error free delivery)
– Access to data recorded on TA storage device
– Ability to change configuration of TA instrumentation
Goals Illustration
Flight Simulators
Telemetry Network System (TmNS) Encompasses:
•Vehicle Network (vNET) (Test Article, TA)•RF Network (rfNET)•Ground Network [Interface only (gNET)]•Serial Streaming Telemetry (SST) Link
Courtesy US DoD/CTEIP iNET Program Office
18
Dedicated LegacyTM Link
Vehicle Data Acquisition Network
Vehicle Data Acquisition Network
Flight Simulators
Ground
Network
Vehicle Data Acquisition Network
Dedicated LegacyTM Link
Dedicated Legacy TM Link
TmNS Encompasses:
RFNetwork
iNET Project Description
Aircraft AntennaGround AntennaNetwork Transceiver
Range Network Interface
RoutersNetwork Data Acquisition UnitNetwork Solid State RecorderCrypto Device
Modified TM Processing AppsRoutersNetwork Instrumentation carts
iNET Deliverables:• TmNS• Network Manager• Spectrum Manager• Architecture• Standards
TelemetryNetworkSystem
Courtesy US DoD/CTEIP iNET Program Office
19
iNET Technical Parameters (notional)
Performance Need Aeronautical and Aircraft Environment
Threshold Objective Current Status
Service Levels (Quality)3 6 Threshold – Demo Sched for late
FY09
Operating Range (w/o relay) 100 NMi (185km) 150 NMi (280km) TBD (50NMi Demonstrated)
Operating Altitude RangeLocal ground level to 65K ft
Local ground level to 75K ft TBD
Maximum TA Speed Mach 2.5 Mach 5 TBD
Simultaneous Test Articles 4 16 TBD
Network Throughput Air to Ground (per instantiation no-relay)
8 X 106 bits per second (8Mbps)
20 MbpsTBD
Network Throughput Ground to Air (per instantiation no-relay)
0.8 Mbps 2 MbpsTBD
Measurand Synch w/in TA 10 usec 1 usec Objective - Demonstrated in LAB
Measurand Synch between TAs 1 millisecond (ms) 100 usec TBD
Highest Operating Information Assurance Levels
Secret Top Secret TBD
Network Spectrum Efficiency 0.76 bits/second/hertz same TBD
Courtesy US DoD/CTEIP iNET Program Office
Telemetry Standards
• European Telemetry Standards Committee– Europe (and others)– www.aktm.org/etsc
• Telemetry Standards Coordinating Council– Chartered by the Int’l Foundation for Telemetering– www.telemetry.org
• Range Commanders Council (US DOD)– Aka Inter-Range Instrumentation Group (IRIG)– Stds made available to ETSC and TSCC
RCC Telemetry Standards
• New Standards – Planned Releases
• New TM Bands• TM Networks (IRIG-106 Vol 2)
– IRIG-106 (Telemetry Standards) Recent Releases• release every 2 years• New Modulation (SOQPSK)• New Digital Recorder formats (Ch-10)• Updates to TM Attributes Standard• Stds for expression of Measurement Uncertainty• On-Board Networks• CPM/Advance Modulation
Summary• The 2007 WRC succeeded in securing additional
radio spectrum resources for aeronautical telemetry. An immediate use must be initiated!
• The new “WRC-bands” will allow the implication of wide band TM links into flight test missions.In Region 3 (Asia & Pacific) up to 59 MHz of usable bandwidth will be allocable.
• Components & systems for either new state-of-the art equipment or for upgrade of existing systems are already in work. Tracking systems & algorithms need an up front evaluation.
• The Indian FT community needs to occupy the bands or they will lose access to critical spectrum.
Commercial interests are hunting to catch more spectrum !!
Conclusions• Test ranges involved in international T & E
missions should utilize telemetering capabilities in the new bands as soon as possible, especially the global harmonized part from 5091 to 5150 MHz.
• Indian goverment was supporting AI 1.5 in the WRC-07 process in a very cooperative way.
• Therefore India Industry and government (HAL, DRDO, etc) is encouraged to take the next consequent step, to implement the C-band telemetry capability in their test ranges in these bands.
Further information
ICTS Web site: www.telemetryspectrum.org
IFT Web site: www.telemetry .org
ITU Web site: www.itu.int/ITU-R/
ERO web site: www.ero.dk
Questions?
Telemetry engineers do it with frequency!
Are you getting enough?