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GPS Augmentations and Enhanced Loran: Infrastructure Precision and Reliability. Asia GNSS Workshop Seoul, Korea - November 4, 2004 s s s s s s s s s s s s s s s s James J. Miller DOT Office of the Secretary. Overview. GPS Augmentations & Applications Wide Area Augmentation System (WAAS)
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GPS Augmentations and Enhanced Loran: Infrastructure Precision and Reliability Asia GNSS Workshop Seoul, Korea - November 4, 2004 s s s s s s s s s s s s s s s s James J. Miller DOT Office of the Secretary
Overview • GPS Augmentations & Applications • Wide Area Augmentation System (WAAS) • Local Area Augmentation System (LAAS) • Nationwide Differential GPS (NDGPS) • Loran developments in the U.S. • Loran Today • Modernizing Loran • Achieving “eLoran”
GPS Augmentations & Applications Satellite Ops --Ephemeris, Timing Personal Navigation Power Grid Interfaces Surveying & Mapping Trucking & Shipping Communications --Network Synchronization and Timing Aviation Recreation Railroads Fishing & Boating Off shore Drilling
New Civil Applications Continue To Emerge • Child safety • Wireless E-911 • Open pit mining • Power grid management • Spacecraft control • Intelligent Transportation Systems
Current GPS Civil Capabilities Maritime Land Aviation Requirements can be Requirements are not met met by GPS alone by GPS alone
GPS Civil Capabilities with Augmentations Maritime Land Aviation Requirements can be Requirements are met by met by GPS alone GPS plus augmentations
Differential GPS (DGPS)Concept . ReferenceStation
Wide Area Augmentation System (WAAS) • Improvesefficiency/capacityof airspace system • Advanced arrival and departure procedures • Promotes airspace redesign • Safetyis most significant benefit • Vertical guidance at all runway ends • Improves 3D situational awareness • GPS/WAASprocedures in place • Certified avionicsare available now • Improved accessto airports for general, commuter, and business aviation • Allowsreduction of ground- based navigation aids LNAV/VNAV 350’ LPV 250’ ILS 200’ 3o
Commissioned for IFR En Route Operations - July 10, 2003 Lateral Guidance 100% of CONUS, Alaska, Hawaii, Puerto Rico Vertical Guidance 95% availability in CONUS & portions of Alaska LNAV/VNAV approaches (350’ minimums) LPV approaches (250’ minimums) first published - Sep 2003 WAAS Expanded LPV Coverage 2008 Full continental U.S. Most of Alaska GPS Modernization ~ 2015 L5 frequency WAAS 200’ minimums Interference mitigation WAAS Status
Local Area Augmentation System (LAAS) • Precision approach for Category I, II & III • Multiple runway coverage • Complex procedures • Guided missed approaches • Guided departure procedures • Aircraft surface navigation
LAAS Status • LAAS directed to be R&D program • CAT I contract becomes focused on integrity and safety • Complete integrity design report and FHA • CAT II/III Research and Development • GNSS/Inertial, EVS, RADALT integration study • Dual frequency LGF design analysis initiation • Ionosheperic threat model/monitoring algorithms • Dual frequency multipath limiting antenna • LAAS future TBD based on results of technical, operational, and economic assessments
Five Categories of NDGPS Applications Categories of ApplicationsProvides 1.Original Code-Based NDGPS Applications1 - 3 meters Navigation, Precision Farming, Positive Train Control, Dredging, Buoy Positioning, Resource Management & GIS 2. Real-Time High Accuracy NDGPS Apps10-15 centimeters Real-time Automated Surveying of Roads, Railroads & Harbors; Highway Lane Keeping;Machinery Control; & Auto-Docking of Ships 3. Post-Processing NDGPS Applications2 - 4 centimeters Surveying, Mapping, Charting & Hydrography 4. Stationary Scientific NDGPS Applications2 - 3 millimeters Plate Tectonics Monitoring & Earthquake Prediction 5. Weather Forecasting ApplicationWater Vapor Info
Nationwide DGPS (NDGPS)Status • NDGPS expansion is progressing • 82 sites currently operational - 86 sites by December 2004 • Single-station coverage – now 92% of CONUS • Dual-station coverage currently 50% of CONUS • Nationwide single coverage by end of 2005 with the addition of 5 more sites • Nationwide dual coverage by end of 2008 • Total of 110 sites in CONUS and 15 sites in Alaska International Standard used in 40 countries
International Standard • NDGPS is designed to an international, non-proprietary standard • Compliant with RTCM SC-104 and ITU-R M.823 • Increases market for manufacturers • Enhances Global interoperability • Signal is free to all users • 47 other countries operate systems compatible to ours • Resulting in a seamless international navigation system
Intelligent Transportation Systems • Improved roadway safety • Minimize accidents • Crash prevention technologies research • Road departure prevention • Electronic mapping • High-Accuracy NDGPS • In-vehicle navigation for precise position determination • Snowplow guidance
New Initiatives - Accuracy High Accuracy NDGPS • Develop a nationwide 3-D dynamic positioning service that has an accuracy better than 15 centimeter and time to alarm integrity of less than 2 seconds • Coexist with existing NDGPS infrastructure GPS (13-24 meters) HA-NDGPS Dynamic(0.1 meters) NDGPS (1 to 3 meters)
HA-NDGPS Status • HA-NDGPS Signal Successfully Broadcast from two locations • Static accuracy at 50 km better than 1cm 3-D • Dynamic accuracy at 250 km better than 20 cm 3-D • Additional testing planned over next several months • Benefits of multi-site broadcast • Atmospheric Prediction Algorithms show promise • Implementation Cost <$100,000 per site
High Accuracy - NDGPS Plans • Whidbey Is • Pattern Wenatchee UpperKeweenaw Robinson Pt Penobscot • Polson Wisconsin Point Spokane Edinburg Fort Stevens Whitefish Pt • Great Falls • Appleton Brunswick Middlebury Neebish Island • Medora Cheboygan Portsmouth Pine River Sturgeon Bay HudsonFalls Billings • Seneca SaginawBay Weiser Clark Medford Acushnet Youngstown St. Paul • Klamath Falls Detroit Elmira Moriches Jackson INEL Cape Mendocino Ledyard Milwaukee Sandy Hook Onondaga Hawk Run Jack Creek RockIsland Iowa City Hagerstown Reedy Point Rawlins Whitney Chico St Mary’s Omaha Cape Henlopen Cincinnati Annapolis St. Mary’s Myton Austin Lincoln KansasCity Point Blunt Topeka Pigeon Point Cape Henry Driver Monterey Goodland St Louis Martinsville Kanab Louisville Pueblo Bakersfield Fort Macon Greensboro New Bern Hartsville Point Arquello • Canton • Fayetteville Ashville Dandridge Essex Memphis Sallisaw Flagstaff Albuquerque • Kensington Charleston Point Loma Bobo Hackleburg Summerfield Tucson Macon • GWEN Sites • New Site • Coast Guard Site • Green - Operating • Red – Planned • Dark Blue – HA-NDGPS broadcasting • Light Blue – HA-NDGPS planned Savannah Grady Munday Vicksburg Millers Ferry El Paso Odessa MobilePoint Cape Canaveral English Turn Langtry Galveston Egmont Key Miami Aransas Pass Key West
NDGPS Partner Projects Continuously Operating Reference Stations (CORS) Program
NDGPS Partner Projects (cont.) NOAA’s Forecast Systems Lab ContinuouslyMeasures Water Vapor NDGPS Site in Whitney, NE
NDGPS Partner Projects (cont.) University NAVSTAR Consortium (UNAVCO) NDGPS Site in Pueblo, CO
Status of Loran in the U.S. • Legacy Loran Today • Loran Modernization – Achievements • Differential Loran • Loran Data Channel • Loran Station Electronics • Control Station Electronics • Loran Modernization – Expectations • Complete Electronics modernization • Implement Time of Transmission (TOT) control • Evolve to Enhanced Loran (eLoran) in both CONUS and Alaska
Legacy Loran • Loran is currently: • A hyperbolic radionavigation system… • …operating between 90 kHz and 110 kHz… • …that uses a very tall antenna… • …that broadcasts primarily a ground wave • …at high power… • …that provides both lateral position… • …and a robust time and frequency standard • A supplemental system for enroute aviation navigation in the U.S. National Airspace System (NAS) • A system for maritime navigation in the coastal confluence zone (CCZ) • A Stratum 1 frequency standard (i.e., 1 x 10-11) that also provides time within 100 ns of UTC (USNO)
Legacy Loran (cont.) • As a radionavigation system, Loran provides: • A predicted 2drms accuracy of 0.25 nm (460 m) and a repeatable accuracy of 60-300 ft (18-90 m)* • An availability of 99.7% (based on triad operation)* • A level of Integrity based on exceeding certain operational parameters measured at the transmitters and at system area monitor sites • Continuity no greater than 99.7% (its availability), but potentially worse depending on receiver characteristics and geometry of the triad being used… • Loran today does not meet high-performance, precision standards relative to other Nav aids… * U.S. Federal Radionavigation Plan (FRP)
New SSX Stations:3 US TTX Stations: 8 US, 1 Canadian SSX Stations w/New TFE: 5 US SSX Stations: 8 US, 4 Canadian LSU Control Stations North American Loran System New TFE also Installed! Baudette, MN; Seneca, NY; Boise City, OK; Malone, FL; and Havre, MT New SSX Installed! George, Washington; Dana, Indiana; and Fallon, NV
Current U.S. Loran Policy “The Government is evaluating the ability of an enhanced Loran system to support non-precision approach for aviation users, harbor entrance and approach for maritime users, and improved performance for time and frequency users.” “If the Government concludes as a result of the evaluations that Loran-C is not needed or is not cost effective, the United States Coast Guard (USCG) will plan to disestablish the system by the end of fiscal year 2008 with appropriate public notice.”
U.S. DOT Navigation Task Force Report “If Loran can meet requirements for non-precision approach for aviation users, harbor entrance and approach for maritime users, and improved performance for time and frequency users, and is cost effective, Loran should be included in the future radionavigation mix.”
eLoran Loran-C Loran Technical Evaluation Conclusions “The evaluation shows that the modernized Loran system could satisfy the current NPA, HEA, and timing/frequency requirements in the United States and could be used to mitigate the operational effects of a disruption in GPS services... “…If the decision is madeto retain Loran as one of the federally provided radionavigation systems, the extent to which these modifications are accepted and implemented will define the actual characteristics of the resulting enhanced Loran (eLoran) system.”
Achieving “Enhanced Loran” • “Enhanced Loran” means a modernized Loran that meets the current requirements of GPS navigation and timing users and, therefore, can be used as a GPS back-up • Requirements must be met for: • Maritime Harbor Entrance & Approach (HEA) • Accuracy within 20 meters • Aviation Non-Precision Approach (NPA) • Probability of Hazardous or Misleading information no greater than 1 x 10-7 per hour • Timing • Within 100 nanoseconds of UTC • Enhanced Loran (eLoran) availability: • CONUS by December 31, 2008 • Alaska by December 31, 2009
Accuracy Availability Integrity Continuity Loran-C 0.25 nm (463 m) 0.997 10 second alarm/ 25 m error 0.997 eLoran 0.004 - 0.01 nm (8 – 20 m) 0.999 – 0.9999 0.9999999 (1 x 10-7) 0.999 - 0.9999 over 150 sec Loran-C vs. eLoran • The Loran technical evaluation showed that eLoran could meet the aviation requirements for non-precision approach (NPA) and the maritime requirements for harbor entrance and approach (HEA)
Loran Data Channel • Loran must transmit information to users to achieve the accuracy, availability, integrity, and continuity requirements for NPA and HEA • eLoran will transmit this informationby adding a 9th Pulse to the Loran transmission • It preserves navigation information on pulses 1-8 • Its feasibility has been proven with solid-state transmitters • U.S. has successfully tested its ability to broadcast and receive station ID, integrity, time, and differential messages • Facilitates all-in-view vs. chain operation • Each Loran station becomes essentially a pseudolite • U.S. is planning to activate 9th pulse at Loran Station Seneca, NY and perform additional testing in Boston and New York using differential corrections from several monitors
Time of Transmission (TOT) Control • Evolving from the current System Area Monitoring (SAM) control to Time-of-Transmission Control is essential to achieving eLoran • All of CONUS should be completed by December 2005, including: • Loran and Control Station electronics modernized • Loran on Time-of-Transmission control implemented • All-in-view/9th pulse receivers development • Differential Loran information developed for specific harbors
New Loran Station Electronics New Solid State Transmitter (NSSX) New Timing & Frequency Equipment (NTFE)
New Control-Station Electronics New Loran Consolidated Control System (NLCCS)
Differential Loran – Real World Maritime Environment Shipboard Installation
Differential Loran – Real Time Vessel’s Track Line Accuracies Achieved
Prototype Loran Card inMulti-Mode Avionics Receiver • Rockwell Collins has continued the work on their own to incorporate low cost gyros into the integrated receiver solution • Integrated GPS/LORAN receiver for general aviation is also being developed by FreeFlight Systems and Locus under FAA contract
FreeFlight/LocusGA Multi-Mode Receiver • Phase I Prototype (Two-box initial solution) similar to GPS/WAAS/LORAN Rockwell Collins MMR/Locus development • Phase I Prototype testing of Integrated GPS/WAAS/LORAN receiver testing progressing at this time
FreeFlight/Locus GA Multi-Mode Receiver • Phase II Prototype to become available for testing Spring 2005
Signal Processor77 x 51 mm Front End & ADC77 x 47 mm Megapulse/Reelektronika/Si-Tek Multi-Mode Marine Receiver GPS – WAAS Prototype became available for testing: Spring 2004 Production units expected: Winter 2004
85 mm 110 mm 30 mm New Loran/GPS/WAAS Megapulse/Reelektronika Receiver
Summary • As the global standard for positioning, navigation, and timing, GPS use continues to grow in all modes of transportation and numerous civil applications • GPS modernization and its augmentations are integral components of the emergingrobust and reliable positioning, navigation, and timing (PNT) infrastructure • Modernization of Loran continues as part of the U.S. transportation infrastructure • The decision to continue Loran services in the U.S. is currently under review. A U.S. government decision is pending • GPS augmentations and “eLoran” type systems all have a potential role to play in theradionavigation and positioning mix of the future Greater PNT capabilities for civil users worldwide
POINT OF CONTACT INFO. James J. Miller, Deputy Director U.S. Department of Transportation, Office of the Secretary Navigation & Spectrum Policy, Nassif Bldg., Rm. 10223E 400 Seventh Street, S.W., Washington, D.C. 20590 (202) 366-5918 jj.miller@ost.dot.gov www.dot.gov