Trends in Aeronautical Flight Test Telemetry

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?