Transcript Title of Presentation Name of Author(s)/Presenter

Ongoing Loran Evaluations at the
Federal Aviation Administration and the
US Coast Guard
Mitchell J. Narins
Systems Engineer
Federal Aviation Administration
Navigation Integrated Product Team
International Loran
Association Conference
Boulder, Colorado
4 November 2003
Purpose of the Evaluations
To determine whether an enhanced Loran system can provide
the:
Accuracy
Availability
Integrity
Continuity
a) to support Lateral Navigation through all phases of flight –
including Non-Precision Approach (NPA)
b) to support Harbor Entrance and Approach (HEA) for maritime
users
To determine what other ancillary benefits can be derived
from the continued provision of enhanced Loran services
e.g., to support Stratum 1 timing and frequency users
To determine if providing these services via Loran is costbeneficial (i.e., Benefits/Costs >1)
2
North American Loran System
First New SSX Station
Installation
George, Washington
New SSX Stations: 1 US
TTX Stations: 11 US, 1 Canadian
SSX Stations: 13 US, 4 Canadian
LSU
Control Stations
3
Program Participants
Government
FAA
 Navigation and Landing Systems Engr, AND-740
 Navigation and Landing System Architecture, ASD-140
 CNS Test and Evaluation, ACB-440
 Flight Standards, AFS-400
 Aircraft Certification, AIR-130
 Special Programs, AVN-5
US Coast Guard
 HQ Aids to Navigation
 Navigation Center
 Loran Support Unit
 Command and Control Center
Volpe National Transportation System Center
4
Program Participants
Industry
Booz|Allen|Hamilton
Free Flight Systems*
Illgen Simulation
Technologies, Inc.
JJMA
Locus, Inc.
Megapulse, Inc.
Peterson Integrated
Geopositioning
Reelektronika*
Rockwell Collins
Timing Solutions
Si-Tex Marine*
WR Systems
Academia
Ohio University
Stanford University
US Coast Guard Academy
University of Rhode Island
University of Alaska
University of Wales*
*New FY 2003 Team Member
5
Loran Program Logo Collection
Booz|Allen|Hamilton
6
Team Contributions to ILA 2003
The U.S. Loran-C Evaluation Program has much to be proud of…and equally
much to report out at this ILA Conference:
4 November:
Loran Integrity Certification

Dr. Per Enge, Stanford University
Loran of the 21st Century

CAPT Tom Gunther (USCG Ret.), Booz|Allen|Hamilton
Loran-C Maintenance Support

CDR John Macaluso, Loran Support Unit
The Challenge of Finding Your Way in a World Hostile to Radio
Navigation

Dr. Durk Van Willigan
On-air with the New Solid State Transmitter

CDR Chuck Teaney (USCG Ret.) WR Systems
The Case for Transitioning to Time of Emission Control in the US

CAPT Curt Dubay, USCG Navigation Center
Loran Operation Performance Report

LCDR Max Caruso, USCG NavCen Detachment
Supporting the Enhanced Loran-C System

LT (jg) Zach Conover, Loran Support Unit
Applications of Differential Loran

CDR Doug Taggert (USCG Ret.), Overlook Systems
Differential Loran

CAPT Ben Peterson (USCG Ret.), Peterson Integrated
Geopositioning
Common-View LORAN-C for Precision Time and Frequency
Recovery

Dr. Tom Celano, Timing Solutions Corporation
Predicted Differential Loran Performance in Boston Harbor

Mr. Andre Grebnev, Megapulse, Inc.
5 November:
Early Skywave Propagation

Dr. Peter Morris, Northrup Grumman
Early Skywave Examples from PCMS Data

CAPT Bob Wenzel (USCG Ret.), Booz|Allen|Hamilton
Mitigation of the Effects of Early Skywave

CAPT Ben Peterson (USCG Ret.), PIG
Getting a Bearing of ASF Directional Corrections

CAPT Dick Hartnett, USCG Academy
Modelling Loran-C Envelope-to-Cycle Differences in
Mountainous Terrain

Dr. David Last, University of Wales – Bangor
Summer Vacation 2003 – ASF Spatial Mapping in CO/AR/FL/CA

Mr. Greg Johnson, JJMA
Analysis of Groundwave Propagation Effects for Loran RNP 0.3

Dr. Sherman Lo, Stanford University
6 November
Loran-C Band Data Collection Efforts at Ohio University

Mr. Curt Cutright, Ohio University
Atmospheric Noise Analysis

Mr. Lee Boyce, Stanford University
FAA Tests and H-Field Antenna to Increase Loran-C Availability
During P-Static

Mr. Robert Erikson, FAA Technical Center
Integrated GPS/Loran Navigation Sensor for Aviation
Applications

Mr. James Doty, Rockwell Collins
Development of an Integrated GPS/LORAN Prototype Navigation
System for Business and General Aviation Applications

Dr. James Davis, Free Flight Systems
Integrated GPS/ Loran Sensor for Maritime Operations

Mr. Wouter Pelgrum, Reelektronika
On Non-iterative Loran-C Time Difference to Latitude/Longitude
Converters
7

Dr. Paul Williams, University of Wales - Bangor
Loran-C Evaluation Program
FY 1994
Federal Radionavigation Plan (FRP) announced that Loran-C
service would terminate 31 December 2000
Congressional lobbying (primarily by aviation groups) resulted
in budgetary language to continue system development
FY 1997 ($4.6 M)
Congressional Mandate

The FY 1997 Congressional budget provided funds to the FAA
for “upgrades to the Loran-C navigation system and... to
implement an automatic blink system (ABS).”
FY 1998 ($3 M)
Congressional Mandate

The FY 1998 Congressional budget directed the FAA “to
continue Loran-C upgrades initiated in fiscal 97.”
FY 1999 ($7 M)
Congressional Mandate

The Congressional budget provided funds to the FAA for “further
development of the Loran-C navigation system.”
8
Loran-C Evaluation Program
FY 2000 ($10 M)
Congressional Mandate

The Congressional budget provided funds to the FAA for
“further development of the Loran-C navigation system.”
FY 2001 ($20 M requested, $25 M provided)
First year included in President’s budget
FY 2002 ($13 M requested, $19 M provided)
FY 2003 ($13 M requested, $25 M provided)
FY 2004 ($0 requested, $20M - $25M expected)
Senate (Appropriations Report) raised the level of funding to
$20 Million
House (Appropriations Report) raised the level of funding to
$25 Million
Awaiting Conference Decision
9
A Most Substantial Investment
U.S. Loran Evaluation Program
Cumulative Expenditures
FY 97 - FY 04
140
Dollars (millions)
120
*
100
80
60
40
20
0
97
98
99
00
01
02
03
04
Fiscal Year
*Assumes $25 M in FY 04
10
Current US Loran-C Policy
“While the Administration continues to evaluate the long-term
need for continuation of the Loran-C radionavigation system,
the Government will operate the Loran-C system in the short
term. The U.S. Government will give users reasonable notice
if it concludes that Loran-C is not needed or is not cost
effective, so that users will have the opportunity to transition to
alternative navigation aids. With this continued sustainment of
the Loran-C service, users will be able to realize additional
benefits. Improvement of GPS time synchronization of the
Loran-C chains and the use of digital receivers may support
improved accuracy and coverage of the service. Loran-C will
continue to provide a supplemental means of navigation.
Current Loran-C receivers do not support nonprecision
instrument approach operations.”
2001 US Federal Radionavigation Plan
11
Volpe GPS Vulnerability Study
The vulnerability study released on 10 September 2001
recognized the potential for Loran-C to be a robust backup
system for GPS navigation and augmentation and timing.
“In an effort to provide the greatest benefit to the users,
encourage the development of affordable vehicle-based backup
such as GPS/inertial receivers, and, in the event Loran-C
becomes a viable terrestrial backups to GPS, aviation certifiable
Loran-C receivers, and GPS/Loran-C receivers.”
“Conduct a comprehensive analysis of GPS backup navigation
and precise timing options including VOR/DME, ILS, Loran-C,
inertial navigation systems, and operating systems.
“Continue the Loran-C modernization program of the FAA and
USCG, until it is determined whether Loran-C has a role as a
GPS backup system. If it is determined that Loran-C has a role
in the future navigation mix, DOT should promptly announce this
to encourage the electronics manufacturing community to
develop new Loran-C technologies.”
12
Loran’s Potential as a GPS Backup
Parameter
Frequency
Propagation
Chief Propagation Errors
Penetration
Modulation
Coverage
Signal Strength
Timing Basis
Tx Location
Utility: Aviation example
User communities
Loran
100 kHz
Groundwave
Conductivity, troposphere
variations
Walls, ground, 6' seawater
TD + CD
To ground level
Relatively high
Triple Cesium
Ground - stationary
En route, terminal airspace
Lateral-guided approach
Multiple (air, land, marine)
GPS
1.2-1.5 GHz
Line of Sight
Iono delay variations*
Very little penetration
Spread spectrum CD
To ground level
Very low by design
Rubidium at present
Space - moving
En route, terminal airspace
Lateral-vertical approach**
Multiple ( air, land, marine)
* Propagation errors are affected at different times and places by components of solar storms
* GPS propagation variations are not correlated with Loran-C propagation errors.
** Vertical-guided "precision" approaches require WAAS or LAAS augmentations.
13
Loran-C Navigation
Current Capabilities/Future Needs*
Accuracy
Current Definition
of Capability *
(FRP)
FAA NPA (RNP.3)
Requirements
USCG Harbor
Requirements
(to date)
Availability
Integrity
Continuity
0.25 nm
(463 m)
0.997
10 second
alarm/
25m error
0.997
0.16 nm
(307 m)
0.999 – 0.9999
0.9999999
0.999 - 0.9999
0.997 - 0.999
10 second
alarm/
25m error
0.9985 – 0.9997
over 3 hours
0.004 - 0.01 nm
(8 – 20 m)
Note: Most stringent requirements shown in aviation orange.
* Includes Stratum 1 timing and frequency capability.
14
Timing User Spectrum
0.1 ns
1 ns
10 ns
100 ns
1 µs
10 µs
100 µs
1 ms
10 ms
100 ms
1s
PTTI/R&D
- NIF
Scientific/
Experimental
National Timing Labs
High Precision Military
- GPS Monitor Stations
- GPS Weapons
- AT3 Airborne Geolocation Demo
- Bistatic Radar
- Other Applications
Advanced Comms
Power Systems
- Fault Location
- Phasor Meas
- Data Sharing
CDMA2000
- Base Stations
Low Precision Military
- Ground Terminals
- VHF Special Comms
Wide Area Data Logging
- Seismic monitoring
- Nuclear Blast Detection
Timing user survey not intended to be a
complete representation of all users.
Requirements have been generalized and
averaged over user groups
Digital Time Servers
- NTP, etc
Astronomy
Authentication
- Internet login
Could be served by Enhanced LORAN (eLoran)
Financial
Transactions
15
Frequency User Range
10-15
10-14
10-13
10-12
10-11
10-10
10-9
10-8
10-7
10-6
10-5
VLBI
National Timing Labs
High Precision Military
- GPS Monitor Stations
- Various Applications
High Precision
Metrology
- Equipment
Calibration
Stratum 1 Comms
- Telcos
- Military GT
- Digital Wideband
CDMA2000
- Base Stations
Low Precision
Metrology
- Equipment
Calibration
Low Precision Military
- Combat Control Systems
Oscillator Manufacturers
- Cal of low-cost xtal
Frequency user survey not intended to
be a complete representation of all
users. Requirements have been
generalized and averaged over user
groups
Could be served by eLORAN
Misc
- Broadcast TV
- Digital Modular
Radio
- IEEE P802.16
Wireless
16
Status of the
Ongoing Loran Evaluation and
Associated System Recapitalization
Accuracy
Availability
Integrity
Continuity
Final Report due to the Departments of Transportation and Homeland Security
March 2004
Loran Evaluation Activities
To determine Loran Accuracy Potential:
ASF* studies and calibration (for both conductivity and terrain)
Receiver/Integrated receiver studies
Loran Accuracy Performance Panel (LORAPP)
Differential Loran study
To determine Loran Availability Potential:
H-Field Antenna/P-static testing
CONUS All-in-view receiver analysis
Noise analysis
SSX and TFE modification evaluations
To determine Loran Integrity Potential:
Loran Integrity Performance Panel (LORIPP)
Time of Transmission/ASF studies
To determine Loran Continuity Potential:
Receiver/Integrated receiver/antenna studies
*additional secondary factors
18
Loran Issue 1: Accuracy
Current Accuracy:
Target Accuracy (NPA):
0.25 nm, 2drms, 95%
0.16 nm (307 m) - RNP 0.3
 0.43 nm (802 m) - RNP 0.5
Target Accuracy (HEA):
Issues
Old timing sources
Old timing equipment
Tube technology
Simple propagation model
No real-time corrections
8 – 20 m, 2drms, 95%
Potential Mitigations
 New cesium clocks
 New timing suite
 Solid State Transmitter
(SSX) technology
New ASF* tables/algorithms
LORAPP (Differential Loran)
*additional secondary factors
19
Flights to Support Characterization of ASFs
August 2002 and March 2003
20
Typical Results
Loran 7
Loran 1 GPS 1
GPS 8
Loran 8
GPS 7
Loran 2
NPA Requirement: 307 m!
Loran 7
GPS 7
Loran 3
GPS 2
GPS 3
21
Flights to Support Characterization of ASFs
July – September 2003
22
Loran ASF Measurement Campaign
Lots of Miles – Lots of Data
Grand Junction, Colorado
Little Rock, Arkansas
Monterey, California
Pensacola/Destin, Florida
23
Loran Issue 2: Availability
Current Availability:
Target Availability (NPA):
0.997
0.999 - 0.9999
Target Availability (HEA):
0.997 – 0.999 
Issues
Precipitation Static
Atmospheric Noise
Loss of Station Power
Lightning
Chain/Stick Availability
Tube overloads
Potential Mitigations
 H-Field Antenna*
 H-Field, AIV Receiver
 UPS
 New Lightning Protection
 All-in-view receivers
 Solid State Transmitters
*Awaiting safety certification
24
Loran Issue 3: Integrity
Current Integrity:
10 sec. alert @ + 100ns or other
specified error conditions
Target Integrity (NPA): 0.9999999*
556m HPL, 10 sec. alert
Target Integrity (HEA): 0.99997**
Issues
Presumed Integrity/
Auto Blink System
Potential Mitigations
 Loran Integrity Panel (LORIPP)
 Loran Accuracy Panel (LORAPP)
*For Aviation: The probability of providing Hazardous or
Misleading Information (HMI) is 1 x 10-7
**For Maritime: The probability of providing Hazardous or
Misleading Information (HMI) is 3 x 10-5
25
Loran Issue 4: Continuity
Current Continuity: 0.997
Target Continuity (NPA): 0.999 - 0.9999
Target Continuity (HEA): 0.9985 – 0.9997
Issues
Same as Availability plus:
Receiver acquisition time
Potential Mitigations
 New DSP technology
 New SSX Switch Units
 AIV/Integrated Receiver
26
Prototype Brassboard Locus Loran Card Installed
in Rockwell Collins Multi-Mode Receiver
Flight Testing Results will be reported out on Thursday
Integrated GPS/Loran receiver for general aviation also being
developed by Free Flight Systems and Locus
27
FreeFlight/Locus GA Multi-Mode Receiver
Similar to GPS/WAAS/Loran MMR development
Phase I Prototype testing of Integrated GPS/WAAS/Loran
receiver testing to commence this fall
28
FreeFlight/Locus GA Multi-Mode Receiver
Phase II Prototype to be available for testing Spring 2004
29
Megapulse/Reelektronika/Si-Tek
Multi-Mode Marine Receiver
Signal Processor
77 x 51 mm
Front End & ADC
77 x 47 mm
30
The Loran Decision Process
What are we doing?
When are we doing it?
When will we be finished?
When will there be a decision?
Final Report due to the Departments of Transportation and Homeland Security
March 2004
The Loran Decision Process
Action
1.
2.
3.
4.
5.
Determine if Loran can provide
the accuracy, availability,
integrity, and continuity to support
non-precision approach for
aviation and harbor entrance and
approach for maritime.
Determine if Loran can provide
benefits to timing and frequency
users.
Determine if Loran can provide
navigation, timing, and frequency
benefits in a cost effective
manner (i.e., B/C >1.0).
Review results of evaluation and
make recommendation to
Secretary of Transportation.
Announce US Gov’t Decision
regarding future of Loran.
Responsibility
1.
Loran Evaluation Team will
provide report to the Department
of Transportation NLT 31 March
2004.
2.
Loran Evaluation Team will
provide report to the Department
of Transportation NLT 31 March
2004.
Loran Evaluation Team will
provide report to the Department
of Transportation NLT 31 March
2004.
Positioning and Navigation
(PosNav) Committee of the
Department of Transportation
Secretary of Transportation
3.
4.
5.
32
The Loran Decision Process
LORIPP
LORAPP
Loran Evaluation Team
compiles technical
findings and BCA Data
into Draft Report
December 2003
Volpe
FAATC
Secretary of
Transportation
Announces Decision
Internal FAA
Review
Loran Evaluation Team
compiles comments
into Final Report
Internal USCG
Review
March 2004
Department of
Homeland
Security
PosNav Committee
members review the
report
PosNav Committee
recommends decision
to SecDOT
PosNav Committee
meets to discuss report
findings and determine
what recommendation
should be forwarded to
The Secretary of
Transportation
33
Department of Transportation
Pos/Nav Committee
Hon. Jeffrey Shane, Undersecretary of Transportation for Policy,
Chairman
Members
Federal Aviation Administration
Federal Highway Administration
Federal Motor Carrier Safety Administration
Federal Railroad Administration
Federal Transit Administration
Maritime Administration
National Highway Traffic Safety Administration
Saint Lawrence Seaway Development Corporation
Surface Transportation Board
Research and Special Programs Administration
US Coast Guard
US Department of Commerce (Geodetic Survey/Weather/Time)
US Department of Defense
US Department of Homeland Security (?)
34
Summary
FY ’03 – Team continued its excellent progress
FY ’04 – Work continues:
Development of multi-mode receivers for aviation and maritime
users
Development of ASF models that include spatial factors based on
both conductivity and terrain factors and temporal factors based
on multiple seasonal measurements to support NPA
Design and development of differential Loran system and means
to transmit ASF “corrections” to users to support HEA
Test of Differential Loran
Completion of timing and frequency testing to determine potential
level of support to user communities
Completion of Benefit/Cost Analysis
Completion of p-static testing
Completion of LORIPP and LORAPP activities
Publication of evaluation report
US Government Loran Decision
35
Questions
Aviation Requirements:
RNP* 0.3 (target); RNP* 0.5 (minimum)
Performance Requirement
Value
Accuracy (target)
Accuracy (minimum)
307 meters
802 meters
Alarm Limit (target)
Alarm Limit (minimum)
556 meters
926 meters
Integrity
10-7/hour
Time-to-alarm
10 seconds
Availability (minimum)
Availability (target)
99.9%
99.99%
Continuity (minimum)
Continuity (target)
99.9%
99.99%
(Source: FAA Loran Evaluation Report, June 2002)
*Required Navigation Performance
37
Marine HEA Requirements
(Primary)
Performance Requirement
Accuracy (target)
Accuracy (threshold)
Alarm Limit (target)
Alarm Limit (threshold)
Integrity (target)
Time-to-alarm
Availability (threshold)
Availability (target/VTS)
Continuity (threshold)
Continuity (target)
Value
10 meters, 95%
20 meters, 95%
25 meters
50 meters
3x10-5
10 seconds
99.7%
99.9%
99.85% over 3 hours
99.97% over 3 hours
(Sources:
FRP, DOT Task Force, TASC DGPS Mission Needs Analysis: Harbor Entrance and
Approach, IMO Resolutions A.815(19) and draft revisions to A.860(20))
38
Marine HEA Requirements
(Backup)
Performance Requirement
Accuracy (backup)
Alarm Limit (backup)
Integrity (target)
Time-to-alarm
Availability (minimum)
Continuity (minimum)
Value
20 meters, 95%
50 meters
3x10-5
10 seconds
99.7%
99.85% (over 3 hours)
(Sources:
FRP, DOT Task Force, TASC DGPS Mission Needs Analysis: Harbor Entrance and
Approach, IMO Resolutions A.815(19) and draft revisions to A.860(20))
39
Timing and Frequency Specifications
Performance Specification
Frequency Accuracy (threshold)
Value
1 in 1012 (averaged over 24 hrs)
No External Antenna
(desired)
Backward Compatibility
(desired)
Integrity Data
Minimum of USE/NO USE Flag
Higher Accuracy Time of Day
Time Tag (Year/DOY/Second)
Leap Second information
Timing Accuracy
<100nsec
Differential Data
Daily Correction
(Source: DOT Task Force, T1X1 letter of Oct 2002)
40