ESA ALIVE Initiative
A Satellite-Based Communication Channel
for the Reliable Distribution of Early Warning Messages
The Alert Interface via EGNOS (ALIVE)
for Disaster Prevention and Mitigation
Presentation Topics
• The requirements for an alert system
• Overview of SBAS (Satellite Based Augmentation
Systems)
• How SBAS meets the alert requirements
• The ALIVE concept
• Possible implementation strategy
The Need for an Alert System
• Disasters are as devastating to advanced nations as
they are to third world~
• Arguably, we are more reliant on technology
• ‘000’s of lives can be saved by early warning and
mitigation
• Disasters do not respect national boundaries
• But one type of communications channel cannot meet
the needs of all citizens at all times
High Level Requirements
• Resilient from terrestrial infrastructure damage
• High level of integrity
• Institutionally owned
• End user device must be ubiquitous
• Global standard, integrated into disaster management
centres
• Cope with several contemporaneous events
Presentation Topics
• The requirements for an alert system
• Overview of SBAS (Satellite Based Augmentation
Systems)
• How SBAS meets the alert requirements
• The ALIVE concept
• Possible implementation strategy
SBAS – an augmentation to GPS
EGNOS – where we are today
• EGNOS is due to become operational in Mar 08
• Technical performance already stable
• Differential corrections for GPS
• Upgradeable to other GNSS including Galileo
• 1-2m accuracy from wide area corrections
• Equivalent to commercial DGPS services
• Integrity alert within 6 seconds if position information is
deemed unreliable
• Free to air at point of end use
• Signals received via geostationary satellite in same frequency
band as GPS
Satellite-based Augmentation
Systems
• Three SBAS Systems:
•
USA: Wide Area Augmentation System (WAAS)
•
JAPAN: Multifunction Satellite Augmentation System (MSAS)
•
EUROPE: European Geostationary Navigation Overlay System
(EGNOS)
• Global service interoperability
SBAS Characteristics
• Institutionally controlled, secure, operated for safety of life applications
• Designed to:
• guarantee adequate message broadcast
• provide integrity of messages
• provide confirmation of transmission
• Receivers are:
• based on GPS receivers
• share same globally accepted standards
• are the most abundant “satellite communication receivers” in the world
• Receivers combine capability of receiving messages with the ability to:
• determine the location of the receiver
• the three existing SBAS together provide a global coverage
Presentation Topics
• The requirements for an alert system
• Overview of SBAS (Satellite Based Augmentation
Systems)
• How SBAS meets the alert requirements
• The ALIVE concept
• Possible implementation strategy
The disaster alert proposal…
• Communication capacity larger than required for system
operation - sufficient margin to send additional ALIVE
messages
• Inherent characteristics appropriate for alert messages
• Ground-based infrastructure is very unlikely to be
affected by a disaster/crisis
• SBAS communication channel cannot be disrupted in a
crisis situation (ARNS protected bands)
Unique opportunity for broadcasting of alert
messages
How SBAS Meets Alert requirements
• SBAS receivers get alert messages and also have their
position simultaneously - only users in target areas
need to act
• Unique worldwide standard - all SBAS receivers are
identical
• SBAS operated with all guarantees - Safety of Life,
Institutional control, 24 hours non stop; confirmation
message is broadcast in time
• Can be implemented in very short time
• Works in places with no operational infrastructure
• Potential global coverage together with all other SBAS
EGNOS Capability
• EGNOS has to respect minimum update rate to comply
with safety of life requirements – primary mission.
• Possibly 35% of bandwidth is available
• A 250-bit message every 3-4 seconds (75 bps)
• Without SA this increases to 140 bps
• Compares favourably to SAR preliminary mission
analysis requirement of 7 bps.
Presentation Topics
• The requirements for an alert system
• Overview of SBAS (Satellite Based Augmentation
Systems)
• How SBAS meets the alert requirements
• The ALIVE concept
• Possible Implementation Strategy
The Alert Interface Via EGNOS
(ALIVE)
• The architecture of ALIVE implementation….
Presentation Topics
• The requirements for an alert system
• Overview of SBAS (Satellite Based Augmentation
Systems)
• How SBAS meets the alert requirements
• The ALIVE concept
• Possible Implementation Strategy
Key implementation issues
• Need for global coverage and international co-operation
• Technical feasibility and potential affects on core EGNOS mission
• Receiver compatibility and functionality and implications for device
manufacturers
• System architecture definition and requirements for on-board
database – thin or thick client?
• Institutional convergence amongst interested governments and
agencies
• Development of revised SBAS international standards
• The need for a flexible data interchange format for collecting and
distributing early warnings over information networks and the
potential adoption of the OASIS CAP standard
Possible Implementation Strategy
Step 1: Presentation of
p 2:
the ALIVE concept to
relevant Disaster
Management authorities (in
progress)
ibility
Ste
3:
Feas
Cons
olidation of
ALIVE
Mission
asse
ssment of
SBA
S
funct
ionality,
Step 4: Propose the SBAS
communication functionality
(incl. ALIVE) in the context of
the GNSS Accompanying
Program for ESA delegations
consideration
Step 6: SBAS
communication function
(incl ALIVE mission)
Implementation Phase and
development of SBAS
ALIVE enabled receivers
Step
Requirements
with
expert
groups
Step 5: Detailed
specifications; message Ste
standardization; detailed p 8:
Disa
Stepdefinition study; test services
EGNOS test Bed ;ster
7: through
prev
SBAS ALIVE enabled
receiver detailed design. entio
Opera
n/mit
tional
igati
integr
on
ation
quali
of the
ficati
SBAS
on
comm
and
.
start
functi
of
onality
oper
(inc
ation
Conclusions
• SBAS cannot be regarded as ‘one stop shop’ for
disaster alert broadcast channel
• Must be seen in context of suite of channels designed
to meet specific needs of citizens
• Commercial satellite communications
• Public mobile networks
• Public fixed networks
• Private mobile data
• Terrestrial broadcast (TV, Radio)
• Internet/email
• Public address
SBAS – an effective, complementary and
inexpensive disaster alert broadcast channel
• The three existing SBAS together provide global coverage and
share the same worldwide accepted standards
• SBAS GPS combine the possibility of warning with the ability to
determine the location of the receiver in the same equipment
• The SBAS systems, having been conceived as safety critical
systems with the necessary built-in features to guarantee
timeliness of delivery, confirmation of transmission and service
availability
• SBAS are institutionally controlled and may readily support the
necessary regulated structures to control service access
• SBAS offers a very low operational cost suitable for a public
service when compared to most other solutions
• SBAS (like other space systems) offers survivability in the event of
many (terrestrial) disasters as well as speedy restoration after the
event
Thank you for your attention
Andrew.sage@helios-tech.co.uk
Javier.Ventura-Traveset@esa.int
Felix.Toran@esa.int