Federal Aviation Administration Alternative Positioning, Navigation & Timing (APNT) Study Update Leo...
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Transcript of Federal Aviation Administration Alternative Positioning, Navigation & Timing (APNT) Study Update Leo...
Federal AviationAdministration
Alternative Positioning, Alternative Positioning, Navigation & Timing Navigation & Timing
(APNT)(APNT)Study UpdateStudy Update
Leo EldredgeOctober 14, 2010
APNT Study Brief to PNT Advisory Board2Federal Aviation
AdministrationOctober 14, 2010
Why APNT?Why APNT?• The transformation of the National Airspace System (NAS) to the Next
Generation Air Transportation System (NextGen) relies on GPS-Based PNT services and suitable alternate PNT services
– Current ATC system cannot be scaled up to handle 2X traffic
– 2X traffic is more than a controller can handle using radar vectors
– RNAV and RNP procedures for trajectory-based operations (TBO)
– Automation will separate aircraft performing trajectory based operations (TBO)
– Controllers intercede to provide “control by exception”
• TBO Operations may require PNT performance that exceeds DME/DME/IRU
• GPS vulnerability to radio frequency interference (RFI) requires mitigation
– Waiting for the source of the interference to be located and turned off is not an acceptable alternative
APNT Study Brief to PNT Advisory Board3Federal Aviation
AdministrationOctober 14, 2010
•Terminal
•Sector
•D
•Ghost
•Sector
•(not depicted)
•Terminal
•Sector
•A
•En Route
•Sector
•02 (GRUPR)
•En Route
•Sector
•01
• (BAASS)
Baseline Airspace Condition
Enabled by Legacy NAVAIDs
• VOR/DME, VORTAC, NDB
• Point-to-Point Navigation
Enabled by Legacy NAVAIDs
• VOR/DME, VORTAC, NDB
• Point-to-Point Navigation
APNT Study Brief to PNT Advisory Board4Federal Aviation
AdministrationOctober 14, 2010
•Feeder
•Sector - A
• Airport Departure
•Sector - D
•D
•D
•Departure Transition
•Sector
•02 (GRUPR)
•Arrival Transition
Sector
•01
•(BAASS)•Dynamic Airspace
•2
•Dynamic Airspace
•1•Ghost
•SectorBig Airspace Concept
Enabled by PBN
• GPS, WAAS, LAAS, DD, DDI
• Area Navigation (RNAV)
• Required Navigation Performance (RNP)
Enabled by PBN
• GPS, WAAS, LAAS, DD, DDI
• Area Navigation (RNAV)
• Required Navigation Performance (RNP)
APNT Study Brief to PNT Advisory Board5Federal Aviation
AdministrationOctober 14, 2010
TBO 3-Mile Separation with RNP
1 nmOverlap
2 x RNP 0.32 x RNP 0.3
DME / DME / IRUPerformance Limit
RNP-1.0
2 x RNP 1.0
3 Mile Separation
TBO (APNT)Requirement
Primary PNT Service: GPS meets all TBO requirements
Alternate PNT Service: DME/DME/IRU won’t support 3 NM separation
Navigation (> 99.0% Availability)
Surveillance (>99.9% Availability)
Positioning
Accuracy (95%)
Containment(10-7)
SeparationNACp(95%)
NIC(10-7)
GNSS PNT(99.0 – 99.999%)
En Route
*10 nm 20 nm
5 nm308m
(7)1 nm
(5)GPS*4 nm 8 nm
*2 nm 4 nm
Terminal *1 nm 2 nm3 nm
171m(8)
0.6 nm(6)LNAV *0.3 nm 0.6 nm
RNP (AR) *0.1 nm **0.1 nm2.5 nmDPA
171m(8)
0.2 nm(7)
SBAS
LPV 16m/4m 40m/50m 2.5 nm DPA
171m(8)
0.2 nm(7)LPV-200 16m/4m 40m/35m
GLS Cat-I 16m/4m 40m/10m 2.0 nmIPA
121 m(8)
0.2 nm(7)
GBASGLS Cat-III 16m/2m 40m/10m
GNSS Enables PBN and ADS-BGNSS Enables PBN and ADS-B
Dependent Parallel Approach (DPA)Independent Parallel Approach (IPA)
Surveillance Integrity Level (SIL)Navigation Integrity Category (NIC)
Navigation Accuracy Category for Position (NACp)
* Operational requirements are defined for total system accuracy, which is dominated by fight technical error. Position accuracy for these operations is negligible.
** Containment for RNP AR is specified as a total system requirement; value representative of current approvals.
AP
NT
3 nm171m
(8)0.6 nm
(6)
DMEOnlyGapLNAV *0.3 nm 0.6 nm
APNT Study Brief to PNT Advisory Board7Federal Aviation
AdministrationOctober 14, 2010
PNT Performance ZonesPNT Performance Zones
5 SM of Airport
Zone- 1Enroute High
CONUS
FL-600
FL-180
5000’ AGL
Zone- 2Enroute Low
CONUS Zone-3 TerminalOEPs + Next 100 Busiest Airports
2° Slope from 500’ AGL
27 SM89 SM
APNT Study Brief to PNT Advisory Board8Federal Aviation
AdministrationOctober 14, 2010
Zone 1, 2, and 3 Geographic AreasZone 1, 2, and 3 Geographic Areas
APNT Study Brief to PNT Advisory Board9Federal Aviation
AdministrationOctober 14, 2010
GNSS Challenges: GPS Testing by DODGNSS Challenges: GPS Testing by DOD
•139,795•66,018•455,805
•Geographical Area Impacted
•Maximum•Miles•2
•Minimum
•Miles•2•Average
•Miles•2
139,79566,018455,805
Geographical Area Impacted
MaximumMiles2
Minimum
Miles2Average
Miles2
•782 Hours•90 days
•Cumulative
•Duration•141 •NOTAMs
•Shortest •1.0 hour
•Average •6.63 hours
•Longest •72 hours
782 Hours90 days
Cumulative
9 Month Duration141 NOTAMs
Shortest 1.0 hour
Average 6.63 hours
Longest 72 hours
APNT Study Brief to PNT Advisory Board10Federal Aviation
AdministrationOctober 14, 2010
Commercially Available GPS JammerCommercially Available GPS Jammer(so called “Personal Privacy Device”)(so called “Personal Privacy Device”)
APNT Study Brief to PNT Advisory Board11Federal Aviation
AdministrationOctober 14, 2010
LAAS Antenna Location
APNT Study Brief to PNT Advisory Board12Federal Aviation
AdministrationOctober 14, 2010
Zeta “SnapShot” System Data
•Baseline/Nominal L1 RF•Broadband RFI straddling L1
APNT Study Brief to PNT Advisory Board13Federal Aviation
AdministrationOctober 14, 2010
… … and a few more “Personal Privacy Devices”and a few more “Personal Privacy Devices”
$55 Ebay
$110 Ebay
$335 Ebay$92 Ebay
$152 Ebay$40 GPS&GSM
www.chinavasion.com
$83 GPS&GSM www.Tayx.co.uk
APNT Study Brief to PNT Advisory Board14Federal Aviation
AdministrationOctober 14, 2010
RFI Challenges without APNT
• Transitioning from 3-mile to 5-mile separation en route and on arrivals outside of 40 nm when a GPS RFI event occurs
• Shifting some aircraft to radar vectors – significant implications
• Rerouting aircraft around interference area to reduce demand
• Throttle back demand to compensate for loss of capabilities like parallel runway approaches
• Limit RNAV/RNP arrivals and departures and reduce options to handling arrivals
APNT Study Brief to PNT Advisory Board15Federal Aviation
AdministrationOctober 14, 2010
APNT Alternative 1APNT Alternative 1Optimized DME NetworkOptimized DME Network
APNT Study Brief to PNT Advisory Board16Federal Aviation
AdministrationOctober 14, 2010
1100 DMEs in Current Nework
APNT Study Brief to PNT Advisory Board17Federal Aviation
AdministrationOctober 14, 2010
DME-DME AlternativeDME-DME Alternative
• Strengths– Leverage existing technology and systems– Least Impact on Avionics for Air Carriers
• Weaknesses– General Aviation generally does not equip with DME– DME-DME equipped aircraft without Inertial are not currently
authorized to fly RNAV/RNP routes– DME-DME, even with Inertial, is not authorized for pubic
approach operations less than RNAV/RNP-1.0– DME-DME interrogations saturate in very high traffic
environments– Will require retention and capitalization of nearly half the VORs
unless GA equipped with DME/DME inertial
APNT Study Brief to PNT Advisory Board18Federal Aviation
AdministrationOctober 14, 2010
APNT Alternative 2APNT Alternative 2Wide Area Multi-LaterationWide Area Multi-Lateration
APNT Study Brief to PNT Advisory Board19Federal Aviation
AdministrationOctober 14, 2010
Passive Wide-Area Multi-Lateration Passive Wide-Area Multi-Lateration (WAM)(WAM)
Combined DME/GBT Network2 - WAM Receives Signal3 - Aircraft Position Determined4 - Aircraft Position Sent to GBT’s
1 –Aircraft Transmits ADS-B Signal6 – Aircraft Uses Own Position for Navigation
5 - TIS-B Sends Position to Aircraft
APNT Study Brief to PNT Advisory Board20Federal Aviation
AdministrationOctober 14, 2010
656 GBT’s for National Coverage656 GBT’s for National Coverage
Communication Coverage: Not Navigation
APNT Study Brief to PNT Advisory Board21Federal Aviation
AdministrationOctober 14, 2010
Combined Network of DMEs and GBTs
APNT Study Brief to PNT Advisory Board22Federal Aviation
AdministrationOctober 14, 2010
Approaches HistogramApproaches Histogram NavCanada Independent Verification Of Data NavCanada Independent Verification Of Data
Instrument Procedures
Meters Feet
Average 9.4 30.8
Max 81.3 266.9
Min 0.0 0.0
Median 8.0 26.1
Std. dev 8.0 26.3
1-sigma 11.0 36.1
2-sigma 23.0 75.5
APNT Study Brief to PNT Advisory Board23Federal Aviation
AdministrationOctober 14, 2010
MLAT AlternativeMLAT Alternative• Strengths
– Accuracy Demonstrated to be within target levels– Compatible with existing WAM Systems
• Weaknesses– Throughput on 1090ES may limit availability– Minimum of 3 sites required to compute aircraft position– Integrity monitoring and Time to Alert may be challenging– More sites may be needed due to limited signal range– Requires a GPS-Independent common time reference– Significant investment in processing facilities and terrestrial
communications network may be required – Use of MLAT for Navigation will require avionics changes
APNT Study Brief to PNT Advisory Board24Federal Aviation
AdministrationOctober 14, 2010
APNT Alternative 3APNT Alternative 3DME Pseudolites (DMPL)DME Pseudolites (DMPL)
APNT Study Brief to PNT Advisory Board25Federal Aviation
AdministrationOctober 14, 2010
Pseudolite Alternative ConceptPseudolite Alternative Concept
• Combined Network of DME/GBTs etc• GPS-Independent Time Reference• 1 Hz Message ID and Time @ Transmit• PNT Data Broadcast Channel
• Aircraft Calculates Position• RAIM Based Integrity Solution
APNT Study Brief to PNT Advisory Board26Federal Aviation
AdministrationOctober 14, 2010
Pseudolite Alternative Pseudolite Alternative • Strengths
– Unlimited capacity– Less complexity for ground-based system– Potential for aircraft based integrity solution– Potential to leverage use of existing DMEs and GBTs– Potential to uplink data other navigation data to aircraft
• Weaknesses– Minimum of 3 sites required to compute aircraft position– Significant investment in processing facilities and terrestrial
communications network may be required – Common GPS-independent timing reference needed– Greatest Impact to Aircraft Avionics– Least mature concept, no standards exist
APNT Study Brief to PNT Advisory Board27Federal Aviation
AdministrationOctober 14, 2010
APNT Timing ServiceAPNT Timing Service
APNT Study Brief to PNT Advisory Board28Federal Aviation
AdministrationOctober 14, 2010
DMEs + Planned DMEs + GBTs
Ground-to-Ground Time SynchronizationGround-to-Ground Time Synchronization
30 dB ofprocessing
gain
GEO: WAAS L5
MEO: GNSS
LEO: MSS
APNT Study Brief to PNT Advisory Board29Federal Aviation
AdministrationOctober 14, 2010
WAAS L5 for Ground-to-Ground Synch.WAAS L5 for Ground-to-Ground Synch.
J/S = 45 dB
STAP
APNT Study Brief to PNT Advisory Board30Federal Aviation
AdministrationOctober 14, 2010
Summary
• NextGen Operational Improvements enabled by performance based navigation capabilities increases dependence on GPS and alternate PNT services
• GPS vulnerability to radio frequency interference needs to be addressed for trajectory based operations at some locations
• Alternatives are being studied for further consideration
APNT Study Brief to PNT Advisory Board31Federal Aviation
AdministrationOctober 14, 2010
QuestionsQuestions