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F E D E R A L A V I A T I O N A D M I N I S T R A T I O N A I R T R A F F I C O R G A N I Z A T I O N Loran Update Mitchell Narins (US FAA) G. Thomas Gunther (Booz Allen Hamilton) Sherman Lo (Stanford University)

Loran Update

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Loran Update. Mitchell Narins (US FAA) G. Thomas Gunther (Booz Allen Hamilton) Sherman Lo (Stanford University). Key Points. Loran technical evaluation report March 2004 - PowerPoint PPT Presentation

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Page 1: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Loran Update

Mitchell Narins (US FAA)

G. Thomas Gunther (Booz Allen Hamilton)

Sherman Lo (Stanford University)

Page 2: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Key Points

Loran technical evaluation report March 2004– Loran can technically satisfy the aviation, maritime,

and timing requirements allowing users to retain most benefits of GPS

While no decision has been made on Loran, work is progressing to implement enhanced Loran (eLoran)– Loran modernization– Loran working groups– Loran timing panel– Loran user equipment development– Loran testing and applications

Page 3: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Loran & its Role in the US Loran is currently:

– A hyperbolic radionavigation system…• …operating between 90 kHz and 110 kHz…• …that uses a very tall antenna…• …that broadcasts primarily a groundwave• …at high power…• …that provides both lateral position…• …and a robust time and frequency standard

– A supplemental system for enroute navigation in the US 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)

Page 4: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Loran Technical Evaluation Report March 2004

Page 5: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

The Evaluation Team’s The Evaluation Team’s ConclusionConclusion“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, thereby allowing the users to retain the benefits they derive from their use of GPS.”

“This conclusion is based on an analysis of the applications’ performance requirements; expected modification of radionavigation policies, operating procedures, transmitter, monitor and control processes, and user equipment specifications; completion of the identified Loran-C infrastructure changes; and results from numerous field tests. Collectively, these create the architecture for the modernized Loran system.”

Page 6: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Loran Modernization

Page 7: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Loran Modernization

Current accomplishments– All stations upgraded to new TFE– All CONUS stations upgraded to SSX

• 11 stations upgraded to Legacy SSX: Baudette, Boise City, Havre, Malone, Seneca, Jupiter, Carolina Beach, Nantucket, Caribou, Grangeville, Raymondville, Gillette, Las Cruces

• New SSX INSTALLS: George, Dana, Fallon, Searchlight and Middletown

– New Loran Command and Control System (NLCCS) installed & operating at NavCen East (NavCen West soon)

Developing– Testing TOT Operations– Loran Enhanced Monitoring System (LEMS)– Loran Information Control and Operations System (LICOS)

Transmitter equipment necessary for eLoran is installed in CONUS

Page 8: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

North American Loran SystemNorth American Loran System

New SSX Installed!

George, Washington;

Dana, Indiana;

Fallon, NV;

Searchlight, NV; and

Middleton, CA

New TFE also Installed! Baudette, MN; Seneca, NY;

Boise City, OK; Malone, FL; Havre, MT; and Jupiter, FL

TTX Stations: 66 US, 11 Canadian

Control Stations

New SSX Stations:New SSX Stations: 55 US

LSU

SSX Stations: 77 US, 44 Canadian

SSX Stations w/New TFE: 6 USSSX Stations w/New TFE: 6 US

Page 9: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Loran Working Groups

Page 10: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Loran Working Groups

Continued assessment and development of Loran for aviation & maritime operations– Standards: Receiver MOPS and system safety

assessment– Refinement of hazard models: noise, variations in

ASF, ECD, etc.– Development of system infrastructure and design:

Early skywave detection network, ninth pulse messages, ASF & dLoran grid, dLoran monitor

This work prepares the necessary assessments, analyses, and documents for certification

Page 11: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Example 1: Early Skywave Testing

Early skywave is a major integrity hazard since it interferes with the desired groundwave– Analogous to GPS multipath

Develop monitor receiver & tests to determine if an event occurred

Develop network to detect event and determine affected area

Develop protocols and message design to warn users

Page 12: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Detecting Early Skywave

Baudette – Dunbar Forest

Boise City – Little Rock

Boise City – Little Rock

From Dunbar Forest, MN & Little Rock, AK (8970 Alpha 1 monitors) 02-03 NOV 2003

Page 13: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Early Skywave Detection Network: Path Midpoints for Early Skywave

Page 14: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Early Skywave Network Simulator

Simulator tests network design against potential early skywave events

– Worst case failures– False alarms

Also test warning algorithms

Plot shows early skywave detection points if all transmitters and SAM used in monitor network

– Red areas are where early skywave could exist

– Highlighted points are detected locations

Page 15: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Example 2: Atmospheric Noise Testing

Atmospheric noise is the major source of noise in the Loran band– CCIR is the standard model

Validation and refinement of CCIR models used for coverage predictions

Development of processing to reduce the effect of noise and improve coverage

Page 16: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Test Locations

University of Minnesota

Oklahoma University

Langmuir Laboratory

Middletown

Loran-C TowerMiddletown, CA

University of MinnesotaMinneapolis, MN

Langmuir LabSocorro, NM

University of OklahomaNorman, OK

Page 17: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Atmospheric Noise Front End

35 KHz BW @ 100kHz BPF

200 Hz BW @ 100kHz BPF

Page 18: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

University of Oklahoma

Locus Loran Antenna35kHz & 200Hz

True Time AntennaTiming

Wide-band Flat Plate Antenna250kHz BW

Page 19: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Preliminary Results

Confirms both CCIR noise levels & amplitude distribution

CCIR suggestion for translation to Loran band seems valid

Suggests that high noise (> 100 dBuV/m) levels are possible for Loran

Suggests that nonlinear processing could produce significant gain

CCIR predicts the above median APD values for our bandwidth!

Predicted and Actual Amplitude Probability Distribution

Page 20: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Example 3: ASF Testing

Validation of ASF models used for integrity and coverage predictions

Test effects of hazards Preliminary development of procedures for

airport survey and generating government supplied ASF for aviation

Preliminary development of ASF grid and monitor density necessary to support HEA

Page 21: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Flight Route for ASF Validation Testing

Page 22: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

FAA Van for Collection of ASF data

Page 23: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Variation of ASF with Altitude

Plane flew back and forth between 2 points at various altitudes: 300m, 600m, 1200m, 1500m, 3000m

ASF variation may be due to antenna directionality, measurement error, etc.

38.85 38.9 38.95 39 39.05 39.1 39.15 39.2 39.25

-2.8

-2.7

-2.6

-2.5

-2.4

-2.3

-2.2

-2.1

-2

-1.9

Lat

AS

F

Seneca

300m300m

600m

600m

1200m1200m

1500m

1500m

3000m3000m

Page 24: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Airship Test for Altitude Variation

Page 25: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Loran Timing Performance Panel

Page 26: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Loran Testing and Applications

Boston Harbor Testing (PIG)

NYC Testing (Volpe)

NM GPS Jamming Tests (Volpe)

Page 27: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Example 1: Land Mobile Testing

Test the use of Loran, Loran & DR, integrated GPS/Loran/DR in urban environments

Test the use of Loran, Loran & DR, integrated GPS/Loran/DR in GPS jamming conditions

Demonstrate when using Loran is effective in an integrated navigation system

Page 28: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Testing of Loran in an Urban Environment

Page 29: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Testing in GPS Jamming Environment

Jamming Begins

Loran & Integrated Loran DR

DR

Page 30: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

User Equipment Development

Page 31: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Certified Receiver Development

Freeflight Locus

Page 32: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

FreeFlight/LocusFreeFlight/LocusGA Multi-Mode ReceiverGA 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

Phase II Prototype will be available for testing Spring 2005

Page 33: Loran Update

F E D E R A L A V I A T I O N A D M I N I S T R A T I O N • A I R T R A F F I C O R G A N I Z A T I O N

Summary

Loran Modernization Proceeding: CONUS completed

Loran Working Groups working to prepare Loran for certification in aviation RNP 0.3 and maritime HEA applications

User equipment and receivers that can support eLoran currently being developed and tested