ESA ALIVE Initiative A Satellite-Based Communication Channel for the Reliable Distribution of Early Warning Messages The Alert Interface via EGNOS (ALIVE)

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

• 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

Presentation Topics

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



Systems)




Presentation Topics

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

• 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

SBAS Characteristics



Systems)




Presentation Topics

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.



Systems)



• Possible Implementation Strategy

Presentation Topics

• The architecture of ALIVE implementation….

The Alert Interface Via EGNOS (ALIVE)



Systems)



• Possible Implementation Strategy

Presentation Topics

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 the ALIVE concept to relevant Disaster Management authorities (in progress)

Step 2: Feasibility assessment of SBAS functionality,

Step 3: Consolidation of ALIVE Mission Requirements with

expert groups

Step 4: Propose the SBAS communication functionality (incl. ALIVE) in the context of the GNSS Accompanying Program for ESA delegations consideration

Step 5: Detailed specifications; message standardization; detailed definition study; test services through EGNOS test Bed ; SBAS ALIVE enabled receiver detailed design.

Step 6: SBAS communication function (incl ALIVE mission) Implementation Phase and development of SBAS ALIVE enabled receivers

Step 7: Operational integration of the SBAS comm. functionality (inc ALIVE mission) in EGNOS

Step 8: Disaster prevention/mitigation qualification and start of operations (could start in 2008)

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

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Documents

ESA ALIVE Initiative A Satellite-Based Communication Channel for the Reliable Distribution of Early Warning Messages The Alert Interface via EGNOS (ALIVE)