Transcript Evolution from Loran-C to eLoran

Evolution from Loran-C to eLoran
By Dr Sally Basker, Mr George Shaw, Dr Paul Williams & Prof David Last
15 February 2010
Prepared for the European eLoran Forum
Contents

Introduction

Definitions

Comparison

Costs
Definitions
Evolution Timeline
Continuous development
1960s
USCG
Loran-C
1970s
1980s
Modernised
Loran-C
1990s
2000s
Prototype
eLoran
All dates are indicative
2010s
eLoran
`
Definitions
USCG
Loran-C
Modernised
Loran-C
Prototype
eLoran
eLoran
The original version of Loran-C (c. 1960s) based on tube transmitters, SAM
control, ASF look-up tables and hyperbolic navigation, requiring large
numbers of people on site. Typical accuracy: 460m (95%).
The original version of NELS (c. 1990s) based on solid-state transmitters,
time-of-emission timing, ASF model, hyperbolic or rho-rho navigation, and
requiring very few people on site. Typical accuracy: 100m (95%).
The GLAs’ system (c. 2008) based on modernised Loran-C together with
(i) Eurofix to carry UTC and differential Loran, (ii) all-in-view navigation,
(iii) precise ASF surveys, and (iii) differential Loran reference stations for
maritime use. Typical accuracy: 10-20m (95%). Real-time prototype eLoran
has been in operation for two years and is now running continuously.
This is the future (c. 2013?) based on prototype eLoran together with
(i) updated station equipment to improve timing stability, (ii) mitigation of
vulnerabilities to ensure high availability, (iii) Eurofix at all stations, and
(iv) modernised control at Brest. Typical accuracy: 10-20m (95%).
Comparison

Capability

Performance

Functionality
Capability: Application Supported
USCG
Loran-C
Modernised
Loran-C
Resilient PNT

Maritime: Ocean
Maritime: Coastal
Prototype
eLoran
eLoran
1






Aviation: NPA


UTC Timing


Precise Timing
1

Land Mobile


IDM


Stratum 1 Freq.


1. Full performance precise timing is not available due to the timing steps used for station synchronisation. Use of
frequency steering in eLoran should enable continuous sub-50ns timing
Performance
USCG
Loran-C
Modernised
Loran-C
Prototype
eLoran
eLoran
460m
100m
10-20m
10-20m
Integrity
Low
Moderate
High
High
Availability
Low
Moderate
Moderate
High
Accuracy (95%)
Capability: Application Supported
USCG
Loran-C
Modernised
Loran-C
Resilient PNT

Maritime: Ocean
Maritime: Coastal
Prototype
eLoran
eLoran
1






Aviation: NPA


UTC Timing


Precise Timing
1

Land Mobile


IDM


Stratum 1 Freq.


1. Full performance precise timing is not available due to the timing steps used for station synchronisation. Use of
frequency steering in eLoran should enable continuous sub-50ns timing
Core
eLoran
Service
Provider
Aviation
Maritime
Time &
Frequency
Land Mobile
Location Based
Services
Application Service
Providers
Users
Functionality: Core System
USCG
Loran-C
Modernised
Loran-C
Prototype
eLoran
eLoran



Solid State Tx



ToE Timing





Remote Control
Tube Tx

SAM Control

Time-stepped Sync

Freq-steered Sync

Fast blink for Int’y

1. Full performance precise timing is not available due to the timing steps used for station synchronisation. Use of
frequency steering in eLoran should enable continuous sub-50ns timing
Functionality: Augmentations
USCG
Loran-C
Prototype
eLoran
eLoran
Eurofix for eLoran


Differential Stations


Rapid Integrity
Modernised
Loran-C

Functionality: User Equipment
Prototype
eLoran
eLoran




Rx: Integrated


Precise Time
1

Nav: Hyperbolic
USCG
Loran-C
Modernised
Loran-C


Nav: AIV ToE
ASF: Look-up


ASF: Model
ASF: Surveyed
Rx: Stand-alone


1. Full performance precise timing is not available due to the timing steps used for station synchronisation. Use of
frequency steering in eLoran should enable continuous sub-50ns timing
Costs: Modernised Loran-C to
Prototype eLoran
Item
ROM Cost
Eurofix per station
165 kEURO
Differential reference station
65 kEURO
ASF surveying equipment
65 kEURO
Costs: Prototype eLoran to eLoran
Item
ROM Cost
Transmitter control system, switch
cabinet, uninterruptible power
supply and monitor receiver per
station
500 kEURO