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1 Universal Access Transceiver (UAT) Briefing for Seminar on Implementation of Data Link and SATCOM Communications 17-19 November 2003 Bangkok, Thailand.

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Presentation on theme: "1 Universal Access Transceiver (UAT) Briefing for Seminar on Implementation of Data Link and SATCOM Communications 17-19 November 2003 Bangkok, Thailand."— Presentation transcript:

1 1 Universal Access Transceiver (UAT) Briefing for Seminar on Implementation of Data Link and SATCOM Communications November 2003 Bangkok, Thailand Rob Strain MITRE CAASD on behalf of Federal Aviation Administration

2 Outline Status of UAT Standards and Spectrum Planning Capstone Overview UAT Technical Overview –History –System Description

3 Status of UAT Standards and Spectrum Planning

4 SARPs and Technical Manual UAT Standards and Recommended Practices (SARPS) development added formally to ACP work program in May 2003 by the Air Navigation Commission Work on UAT SARPS began by ACP WG-C (formerly AMCP) in June 2002 (initially at risk) Mature drafts of core SARPs and Technical Manual are available. SARPs and Tech Manual development entered a validation phase in Oct 2003 with completion and approval by the full panel targeted for –Validation will include some testing of FAA ground station equipment and certified avionics. –Frequency planning criteria for UAT will be finalized during validation period

5 UAT SARPs and TM (Concluded) SARPs and TM development build upon existing UAT equipment certification baseline (MOPS/TSO) and over 2 years of operational experience with UAT UAT frequency planning criteria are being developed based upon RTCA/FAA testing, amplified by ACP/UAT subgroup analysis for both en route and terminal/approach scenarios.

6 UAT Certification Baseline Activities initiated by RTCA in December 2000 in response to high priority FAA request for industry-developed standards for UAT Tasked to develop Minimum Operational Performance Standards (MOPS) for a UAT-based ADS-B system on an accelerated schedule Document approved by PMC on August 2002 (DO-282) TSO-C154 approved Nov 2002 as basis for equipment certification

7 Participants in Development of UAT MOPS/TSO FAA (Certification, Spectrum, Technical Center, Flight Standards, Safe Flight 21 Program Office, Alaska Region) Eurocontrol U.S. Department of Defense AOPA SSA/FAI UPSAT Rockwell Collins Garmin Boeing L3Comm Analytics BAE Systems Sensis Johns Hopkins APL Mitre Trios Titan PMEI

8 UAT MOPS 40 page compliance matrix for ADS-B MASPS (DO-242A) and FIS-B MASPS is available UAT also designed toward, and UAT performance assessed against, extended ADS-B air-to-air range criteria from Eurocontrol (A3-to-A3 air-to-air performance in Core Europe 2015 Scenario of TLAT estimated to be miles) TIS-B requirements are expected to be accommodated by UAT

9 UAT Frequency Planning Criteria (1) 978 MHz selected as candidate UAT frequency –Worldwide assignments on this frequency consist of 7 DME/TACAN in Europe UAT design objective is compatibility with DME without impacting DME/TACAN assignments on channels other than 978 –RTCA/FAA analysis indicates that this objective has been achieved –UAT subgroup performing further analysis For the UAT subgroup, DFS has performed a worst case enroute environment study on UAT compatibility with DME. DFS has proposed en route frequency planning criteria that involves vacating only the 978 MHz channel

10 UAT Frequency Planning Criteria (2) UAT compatibility with JTIDS/MIDS system has also been achieved with analysis including both future high and low density airspace. US authorities approved 978 MHz UAT frequency for national use on 16 April 2003 based on the aid to radionavigation footnote for the band (Footnote 5.328). ICAO is seeking an opinion from ITU on the applicability of the above footnote. If ITU indicates that Radio Regulation changes are needed for UAT operation in the MHz band, any such changes could be addressed under an existing agenda item at WRC 2007.

11 Aircraft Integration of UAT Avionics Integration into small aircraft has been demonstrated through FAA Capstone Program. Success of this integration is evidenced by over 2 years of successful operational use. Integration into air transport class aircraft through sharing of the SSR transponder antennas has been analyzed and tested in detail. Results are positive, and this potential integration path is being coordinated with ICAO SCRSP. Detailed SCRSP consideration of UAT/SSR antenna sharing and cosite compatibility is scheduled for Feb 2004.

12 Capstone Overview

13 JZ Z IIK 5S8 4Z4 SCM AK85 PT U KLG RSH MOU Bethel Capstone Phase I: Yukon - Kuskokwim Delta Region is nearly 100% dependent upon aviation High accident rates No surveillance radar coverage below 5000 ft Bethel is the hub for 50+ villages Equipping 200 single and twin engine aircraft (air taxi) –All costs incurred by the FAA Planning 10 ground stations for this region Connectivity with Anchorage ACC

14 Capstone Services ADS-B (air-to-air) – Provides enhanced see and avoid CFIT (onboard avionics) –Provides terrain awareness ADS-B (air-to-ground) – Enables ATC services via Anchorage ACC TIS-B (ground-to-air radar targets) * – Completes see and avoid FIS-B (weather uplink) – Provides weather awareness Flight Dispatch Services –Provides flight following and asset management services Future services

15 Avionics Selection FAA solicits avionics proposals for integrated system of GPS, terrain data base, cockpit display and broadcast data link. UPSAT awarded the avionics contract--with UAT as the datalink –best overall system cost –avionics package judged to have best probability of implementation within aggressive Capstone schedule

16 Capstone Communication and Control System (CCCS) Weather Archive& Display ATC System (MicroEarts) Maint & Monitor Anchorage Center UAT Multi- Function Display (CDTI) ANICS ADS-B FIS-B TIS-B FIS-B ADS-B GPS Capstone Architecture Remote Site(s) UAT ADS-B TIS-B FIS-B Ground-based transceiver (GBT)

17 Capstone Avionics Universal Access Transceiver (UAT) GPS Receiver Multi-function Display

18 Avionics Install Kit

19 Ground Broadcast Transceiver (GBT)

20 Typical Capstone Aircraft

21 Traffic and Terrain Display C182R +11

22 FIS Weather - Graphics

23 FIS Weather - Text

24 First Operational use of Radar-Like Services-- January 2001 / 0018Z Controller vectoring Capstone-equipped aircraft to Bethel, Alaska ILS Runway 18, below radar coverage Maintaining separation from a second Capstone- equipped aircraft using ADS-B System certified as part of NAS for routine use

25 Capstone ATC Perspective ADS-B source displayed only if radar unavailable for a given target ADS-B target positions are updated at 6 second rate (adaptable) –1 sec update of velocity vector provides rapid indication of turns for ADS-B targets 5 nmi separation standard: ADS-B or Radar Track bonding logic ensures single target depicted in cases where radar/ADS-B coverage overlaps ADS-B targets auto-acquire via 24 bit address filed in flight plan remarks Symbology allows differentiation of Radar and ADS-B targets

26 Some Operational Experiences (1) ADS-B accuracy found consistently superior to radar for ranges greater than 5 nmi from sensor ADS-B at 1 second transmission rate: –robust to any single message loss –provides rapid turn indications to ATC –aids track bonding –BUT, increases communications/processing load for ATC automation (LAN upgrade recently completed to accommodate additional ADS-B sites)

27 ADS-B reports (1 second transmission interval) Radar returns (12 second scan interval) Cape Newenham radar 130 nmi range Flight of FAAs N40 with Capstone avionics in vicinity of Bethel AK, 21 Aug 2000

28 Some Operational Experiences (2) Possible limitations of ADS-B self-reported integrity (NUC) for some GPS implementations –supplement with independent ground ATC monitoring in Capstone Capstone providing operational feedback to RTCA Replicate transponder indicators (IDENT, 4096 code) Adjustments to the way GPS integrity is reported (NIC vs NUC) Integrity of 24 bit address (installer discipline, pilot access)

29 Capstone Phase II: Southeast Alaska Extend ADS-B coverage with up to 30 additional sites in Southeast Alaska FAA equipping additional 200 aircraft in the Juneau area during. –150 fixed wing and 50 helicopters –Will be UAT MOPS compliant All Phase I UAT installations to be upgraded per UAT MOPS THEN Self Equippage

30 Summary Points UAT has been proven to support the provision of radar- like services in actual ATC operations in Alaska for nearly 3 years--the first ATC operational use of airborne ADS-B worldwide Many areas of the world with little or no radar coverage could benefit from ADS-B in a similar manner. UAT has been proven to be an attractive, cost-effective ADS-B data link for this type of environment. Work currently in progress on UAT SARPS allows its consideration by other States as an ADS-B data link

31 UAT Technical Overview

32 A Brief History of UAT Began around 1995 as part of an independent research project on broadcast data link –6 prototype systems flown on small aircraft –ADS-B, TIS-B, and Wx uplink demonstrated Cargo Airlines incorporate UAT in their evaluation--UPS- AT develops UAT UAT becomes part of SF-21 Link Evaluation study – UAT part of winning bid for FAAs Capstone program

33 UAT Overview Designed specifically for ADS-B and Broadcast Uplink Surveillance-Related Services with no constraints from legacy systems Simplicity and robustness were paramount design objectives Operates on a single common wideband channel 1 Mbps channel rate Capable of supporting multiple broadcast applications to foster early equipage

34 UAT Ground Transceiver Tracker ATC Surveillance Radar ADS-B TIS-B (non-ADS targets) ATC System Tracks Observations WX Radar Forecasts Graphics SUAs Weather Server FIS-B ADS-B air-ground ADS-B air-air FIS-B TIS- B UAT Airborne Transceiver UAT Applications and Connectivity

35 Waveform Selection Requirements –Good capture effect –relatively efficient and low cost power amplifier –simple/robust decoder Binary FM with high modulation index chosen

36 Frequency Band Selection Aeronautical band alternatives: –VHF: MHz –L-band: MHz –C-band: MHz Extremely difficult to assemble enough contiguous channels at VHF Propagation loss too high at C band MHz has best combination of: –channelization (1 MHz) –compatible current usage (pulsed systems) –and propagation characteristics

37 UAT Media Access Approach Ground Broadcast (32 time slots) UAT Frame = 1 sec. Aircraft Reports (random) Ground Message (432 bytes payload) ADS-B Message (18/34 bytes payload) Requirement: Simple and Robust logic for aircraft media access ADS-B transmissions occur based on pseudorandom selection of one of 3200 Message Start Opportunities (MSO)

38 ADS-B Message Format Each aircraft transmits exactly one message each second Standard Forward Error Correction (FEC): –increases message robustness to pulsed interference and noise –provides an extremely low undetected message error rate ~10 -9

39 Independent ADS-B Report Validation: Aircraft Perspective ADS-B message payload includes the precise transmission time (MSO) Receiving aircraft UAT reports precise time of reception with decoded message payload Application can perform passive range verification of ADS- B reported position Flight test data showed time-based slant range estimates to be within 0.2 nmi of that indicated by ADS-B ADS-B message plus transmission time

40 Summary System designed specifically for ADS-B performance and for compatibility in the band Simplicity and robustness drive the design –Every ADS-B message has a complete State Vector without field truncation no lat/long decompression, participant tracking, multi-message assembly, or ambiguity resolution required –High integrity link layer directly aids certification of applications with stringent requirements –Consistent transmission epoch in all flight domains –No channel sensing required: minimal transmit-only implementations viable –Single fixed frequency operation for full suite of services

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