Projet Projet AFREFAFREFECA Geo-information ECA Geo-information Systems SectionSystems Section Dozie EzigbalikeECA Geo-information Systems Section

In Brief

A scientific project using modern satellite based positioning to: Define a uniform geodetic reference frame Africa,

which will form the basis of national three-dimensional reference frames consistent with the International Terrestrial Reference Frame (ITRF)

Establish a network of GNSS base stations for mapping and position determination all over Africa

Support scientific research in satellite

Continental Coverage

Network of permanent GPS/GNSS base stations covering the whole continent

At least one in every country

Eventually, everywhere in Africa less than 1000 km from a base station

African Ellipsoid

Data from the base stations will be used to compute the parameters defining the best-fitting mapping surface for the African continent

Geodetic Reference Uniform geodetic

reference frame for Africa Basis for national three-

dimensional reference networks

Consistent with the International Terrestrial Reference Frame (ITRF)

Precise positioning requires real-time differential observations with two receivers AFREF will provide

network of base stations for practitioners

Major Uses and Applications

Regional Integration Watersheds, river

basins, ecosystems, wildlife are cross-border features

Regional infrastructure: roads, rail lines, water ways, …

Projects usually start at opposite ends

All require uniform mapping surface for regional analysis and planning

Peace and Security AU Border programme to delimit and demarcate

all borders by 2012 requires neighbouring countries to agree on common borders

This requires the borders to be mapped on the same coordinate systems That is, the same mapping surface The same reference frame

Presently, every country has its own reference frame and associated coordinate systems Country borders drawn on these national coordinate

systems are not always consistent Uniform coordinate system of AFREF will result in

consistent representation of borders by neighbours Reducing disagreements and conflicts

Global Conformity

AU vision for Africa … “which asserts itself as a vibrant and dynamic force in the global arena”

Not yet in geodesy AFREF will result in better fit of Africa to rest of

the world

International Mapping Standard

Current positioning technology based on satellite systems (GNSS) Positions are defined in the World Geodetic System

(WGS) International Civil Aviation Organization

(ICAO) adopted World Geodetic System (WGS84) for consistent mapping of Reference Points (ARP)

African countries are complying using satellite positioning technology

Need to have other geoinformation products (topography, cadastre, etc) in similar satellite-based coordinate systems

Other Uses

Disaster mitigation Search and rescue

Vehicle tracking and fleet management Agriculture Monitoring

Crop Area mapping … …

Climate & Weather Estimation of precipitable water vapour from network of

GNSS stations in South Africa

PWV for March 2004

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Atmospheric Research

Atmospheric research Space weather

o Ionospheric mapping of variation of annual TEC over South Africa from network of GNSS base stations

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20022004

Thanks to B Opperman of Hermanus Magnetic Observatory for plots

Atmospheric Research 2

Plate motions Plate motion estimates in South Africa from network of

GNSS base stations

C.J.H. Hartnady, E. Calais & R. Wonnacott (2007): “ITRF2000 velocity field from the South African TrigNet GPS array and the African GNSS network: Implications for Nubia-(Rovuma-Lwandle-)Somalia plate motions” East African Rift Conference, Kampala

Geophysics Research

Objectives and Expected Outputs

Formal Objectives 1

To determine a continental reference system for Africa consistent and homogeneous with the global reference frame of the ITRF as a basis for national three-dimensional reference networks.

To realize a unified vertical datum and to support efforts to establish a precise African geoid.

To establish continuous, permanent GNSS base stations at a spacing such that the users will be within 1000km of a base station and that data is freely available to all nations.

Formal Objectives 2

To determine the relationship between the existing national reference frames and the ITRF to preserve legacy information based on existing frames

To provide a sustainable development environment for technology transfer so that these activities will enhance the national networks and other applications

Assist in establishing in-country expertise for implementation, operation, processing and analysis of modern geodetic techniques, primarily GNSS.

Institutional Acceptance 1 Un Economic Commission for Africa

CODI (now CODIST) an inter-governmental body of ECA Have adopted the importance of AFREF and the Windhoek

Declaration Created a Working Group to deal specifically with AFREF AFREF field project in work programme of ECA

UN Office for Outer Space Affairs (UNOOSA) Have recognized importance of AFREF for variety of applications Supported the Cape Town workshop and funded travel of

participants to several AFREF-related events International Association of Geodesy (IAG )

Have recognized importance of AFREF and have committed support

Have created structures to co-ordinate project and provide technical assistance expertise

Supported the Cape Town workshop

AFREF Structure (1)

To be designed, managed and executed from within African

Regional organization into: NAFREF, WAFREF, CAFREF, EAFRAF, SAFREF

To be executed at the national level by national organizations responsible for geodetic matters

Technical expertise and support from the international geodetic community such as IAG, IGS etc.

AFREF Structure (2)

BureauSteering

Committee

AMCOST

AFREF Joint Secretariat

AU/HRST ECA/ISTD

Technical AdvisoryWorking Group

Scientific AdvisoryWorking Group

Sudan

Algeria

Egypt

Mauritania

Moro

cco

Libyan Arab Jamahirya

Tun

isia

Western Sahara

Mali Niger

Nigeria

Gh

ana

Guinea

Côte D'Ivoire

Senegal

Burkina Faso

Ben

in

Liberia

Tog

oSierra Leone

Guinea-Bissau

Gambia

Cape Verde

Chad

Congo

Cameroon

Gabon

Central African Republic

Equatorial Guinea

Sao Tome & Principe

Ethiopia

Tanzania

Dem. Rep. of the Congo

Kenya

Somalia

Madagascar

Uganda

Eritrea

Burundi

Rwanda

Comoros

SeychellesSouth Africa

Namibia

Zambia

Mozambique

Botswana

Zimbabwe

Ma

law

i

Lesotho

SwazilandNAFREFWAFREF CAFREF EAFREF SAFREF

Sub RegData Processing SRDPSRDP SRDP SRDP

Planned Activities 2008-09

May – June 08: Develop draft open data access policy and draft participation charter

June 08: Meeting of Current AFREF Steering Committee during Africa Array meeting in Johannesburg

June – Nov 08: Installation of five reference stations donated by Trimble

July 08: collect data on ongoing GPS/GNSS projects and initiatives in Africa

Aug 08: Training session at RCMRD Mar 09: CODIST Meeting

• The strategy leads with building a Partnership with The strategy leads with building a Partnership with Providers.Providers.

• Contacts with Trimble

• Donation of the five GPS reference stations equipment that will add

to the network of stations, for the determination of the African

reference frame as well as being part of network of continuously

observing reference stations (CORS).

• In addition, the Commission has developed a proposal to densify the

network such that positioning professionals (surveyors, engineers,

environmentalists, mineral prospectors, etc) would always have

access to parameters of at least one reference point within 500Km

from any place in Africa

AFREF : Operationalization 1

• The strategy leads with organizing an African The strategy leads with organizing an African Policy Makers’ Workshops.Policy Makers’ Workshops.• To channel the Project into the NEPAD’s Programme on Science

and Technology

• To set up the activities into the umbrella of the ministerial

structures of the African Union, notably the African Ministerial

Council on Science and Technology (AMCOST).

AFREF : Operationalization 2

Designation CostTotal Cost

  Y1 Y2 Y3  

1. Equipments 110 000 1 166 000 1 078 000 2 354 000

2.Capacity Building 105 000 287 000 271 000 663 000

3. Services 168 000 168 000 168 000 504 000

4. Management 200 000 200 000 200 000 600 000

5. Others costs 278 577 278 577 278 577 835 730

Grand Total 861 577 2 099 577 1 995 577 4 956 730

AFREF : Funding