Galileo gnss

Galileo GNSSIncoming Future

Prof. Goran Vojković, Ph.D.

9A3QY

[email protected]

Europe invests 3.4 billion €

www.vojkovic.info 2

Photo: ESA

History• Currently there is only one fully functional global

navigation satellite system, The Global Positioning System(GPS).

• GPS was to serve for military purposes only and has replaced old systems such as Transit from the 60s which and required several hours to locate one’s position.

• After tragedy of Korean civil Boing 747 (Flight KE 007) which was brought down by the Soviets on August 31st, 1983 , due to entering their space, President Ronald Reagan ordered free use of GPS system for civil use.

• Its accuracy for civil use was decreased. Function called Selective Availability ensures potential mistakes within 100 meters range.

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GPS as we know it• When Gulf War started in 1990, Americans and allies

simply did not have enough military GPS devices so

the soldiers started to use civilian devices available

on market. Selective Availability was turned off in

order to achieve accuracy.

• Extremely influential Federal Aviation Administration

lobbied to see Selective Availability permanently

turned off.

• Programmed error was officially switched to zero on

May 1st, 2000 by the decision of President Bill

Clinton.

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What do we have?• GPS is now public and free for civil use – according

to announcement of American Department of

Defence from September 19th, 2007 and new

satellites do not even have an opportunity to switch

Selective Availability on – the USA developed

function of local interference of accuracy.

• However GPS (full name NAVSTAR-GPS) remains

under military supervision of US Department of

Defence and is formally a military system!

• The only existing alternative, Russian GLONASS is

also a military system.

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Disadvantages• Military system – despite promises given by the US;

no one can ensure that in case of crisis US would

not limit the system.

• System is not precise enough on high geographical

latitudes while the polar flights are more frequent.

• The most important: GPS does not have system of

error reporting! In case of damaged system GPS

does not inform user to rely on another navigation

system. That is why GPS has not reached the status

of primary navigation system.

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Insufficient reliability• Canadian authorities documented a case of GPS

signal being disconnected for 80 minutes.

• Similar happened in some US states while aircraft

captains reported on certain problems above the

Atlantic and Mediterranean.

• Probably there would be more problems but they

were considered to be errors of receiver or

consequences of atmospherical changes.

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European way• In the first phase in 1999, several concepts have

merged (Germany, Italy, France and UK) and

created unique engineering team for system

development.

• It was instantly decided that primary duty of the

system is civil - possibility of disconnection was to

be limited for exceptional conditions only.

• It was also decided that the system would be

equally precise for both civil and military purposes.

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Interoperability• After September 11th, 2001, the US Government stood

against European plans stating that such a plan would disable the US to disconnect global navigations satellite system in the time of military operations.

• Such US reaction only convinced Europe that they need their own, independent system, and during 2004 safety issues were raised with Americans.

• Planned modulation was changed and enabled GPS and Galileo systems’ co-existance.

• EU agreed with certain safety compromises such as frequency system adjusting so that Galileo system may locally be blocked in a way for military use of GPS stay possible.

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Managing• Until 2007, Galileo is in

deep crisis with only one satellite launched -GIOVE-A.

• Project was lead by the several companies’ consortium called European Satellite Navigation Industries. However, during 2007 EU took over direct management of the project.

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Milestone• In April 2008, when EU

Ministers of Traffic

approved new legal

regulation that ensured

quality project

budgeting – EU

approved 3.4 billion

Euro assets.


Photo: ESA

What do we want?• System Galileo will consist of 30 satellites upon

completion (27 operable and 3 in backup) divided

into three circle orbits on 23,222 km and should

cover the whole territory of Earth.

• It was planned to reach better coverage of high

geographical latitudes where we face very alive air

traffic.

• It should have better coverage of urban zones.

• It will implement several various services.


Interoperability• As agreed with the

US, interoperability of

Galileo and GPS

systems is reached

which ensures better

accuracy.

• As example would be

professional devices

that combine GPS and

GLONASS.


New accuracy• EU has reached three criteria as Galileo priorities, based

on current experience:

o Accuracy,

o Reliability and

o Safety.

• Satellite locations will provide accuracy better than one meter – which will ensure automatisation of operations such as sailing into port, navigating vehicles on parking lot or accurate navigating agricultural machinery.

• Completely new services such as assistance for blind persons.

• Reliability is reached by harmonizing satellites and informing users by a special message in a case of system error.


Feedback?• One of sub-projects within Galileo covers possibilities

of feedback in case of danger.

• Should satellites be projected as transceivers – it will

be possible from any part of the world (with proper

equipment)to send a signal for danger.

• Satellites would redirect that signal towards Earth

where it would be forwarded, with location data, to

authority in charge for rescuing in certain state.

• It is an idea to have the system return a feedback

to the one who requested help.


Political decision• Talking about an important and complex project of

EU such as Galileo, without referring to politics,

would not be proper.

• Galileo is one of the answers on a question how to

reach technological independence of Europe.

• Europe counts that Galileo will generate new

markets and services with value per year of 10

billions Euro, with 100,000 new jobs. Is it publicity or?


Pro/contra• Those who are familiar with satellite navigation

technology will say Galileo does not bring anything new: today is already possible to reach high accuracy of GPS by additional land transmitters and is also possible to send a signal for danger via satellite phone. Also it is possible precisely and with reliability navigate aircrafts via special navigation systems…

• However Galileo, except for being the first civil system of a kind, firstly offers simplicity that current solutions do not support (without additional land transmitters), when sending an information or implementing new service.


New services• An interesting thing

about Galileo is that it

should offer more levels

of services.

• With an emphasize on

“it should” – Galileo is

still under test phase,

while four operative

satellites are functional

only in short periods.


Photo: ESA

The Open Service (OS)• Galileo’s Open Service is provided for wide use. It

sends signals for time determination and location available to every user with proper receiver, no authorization required.

• This service can be combined with American GPS signal which should improve performances in urban and other areas where sky visibility is weak.

• Open service will not offer information integrity to the users; quality of signal and service is something users themselves will have to take care about. In other words, this service will be much alike like the one offered by GPS.


Safety of Life Service (SoL)

• Safety of Life Service will be special service that will require certified receivers with possibility of

receiving two frequency extents. Future Galileo

Operating Company will guarantee certain quality.

• This service will use frequency areas reserved for

aeronautical radio navigation.

• SoL should increase security, particularly in areas

without classical land safety services, while air and

naval companies should benefit from such on

global level.


Commercial Service (CS)• For those who would require higher level of service that

Open Service, Galileo system will provide Commercial Service. This service will provide higher level of service than the Open one, but such will be charged.

• Commercial Service is based on additional two signals to the signals used by Open Service. Those additional signals are coded which makes using Commercial Service possible only once an entry code is entered into receiver.

• This signal can also broadcast data: potential providers will be allowed to lease two commercial portable channels and use such for global broadcasting various information. Additional signals may be used for other purposes such as local broadcast of signal for extremely precise locations.


Public Regulated Service (PRS)

• Among services provided by Galileo there is also Public Regulated Service for governmental and other public users, coast guard and similar organizations.

• Naturally this service will also be protected by appropriate codes.

• In comparison with other services, Public Regulated Service will be functional with all circumstances and conditions even with crisis (when other services may face disconnection). It is important to point out that this service will use signal with modulation with increased interfering resistance.


Search and Rescue (SAR)• Function of Search and Rescue is listed as

“European contribution to international efforts of

humanitarian search and rescue” within papers of

EU.

• This function should improve existing systems and

ensure current signal for help from any point on the

Earth and precise location of it, even in difficult

conditions for communication.

• One should stress out the possibility of feedback link

from the provider of SAR system according to the

device which broadcasted signal for help.


Where is Croatia?


Photo: ESA

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