AMMA - GPS network

O. Bock Prepared for Leeds meeting, April 2006.

Status of implementation on April 1st 2006

O. Bock, IPSL/SA, France

• GPS science team:– Olivier Bock (IPSL/Service d’Aéronomie, CNRS, Paris, France)

– Marie-Noelle Bouin (IGN/LAREG, Marne-la-Vallée, France)

– Erik Doerflinger (LDL, CNRS, Montpellier, France)

– Philippe Collard (LDL, CNRS, Montpellier, France)

– Frederic Masson (LDL, CNRS, Montpellier, France)

• Support teams: gratefully acknowledged !– France: INSU, IGN, Meteo-France, IRD

– Bénin: mainly IRD - Cotonou

– Niger: mainly IRD - Niamey

– Mali: IRD - Bamako, ASECNA and DNM - Gao and Tombouctou

– Burkina-Faso: IRD - Ouaga, CNRST, EIER,

– Ghana: Met. Service in Tamale and Accra

GPS team and support teams

O. Bock Prepared for Leeds meeting, April 2006.

Summary (1/2)

EOP Gao Niamey Djougou

Installed (temp)

(AMMA)

(replaced)

June 05 (GPS)

Aug 05

Dec 05

June 05 (GPS)

Aug 05

Dec 05

June 05 (GPS)

Aug 05

Equipement GPS + PTU GPS + PTU GPS + PTU

Telecom Inmarsat Inmarsat

Data transfert freq. Daily: Jan 06 - NRT planned Daily: Jan 06 -

Data processing 1 - 2 month latency NRT planned 1 - 2 month latency

Main problems - GPS recv breakdown (Sept 05, Mar 06)

- Inmarsat unreliable

No telecom connexion until April 06

- Power shortage (nearly no data lost)

- Inmarsat unreliable

Forthcoming upgrades - GPS recv to be replaced in April 06

April 06: VSAT connexion and data transfert

- Data transfert in failure since 27 Feb. 06

Summary (2/2)

SOP Tombouctou Ouagadougou Tamale

Installed (SOP) April 06 April 06 April 06

Equipement GPS + PTU GPS + PTU GPS + PTU

Telecom GSM GSM GSM

Data transfert freq. 24 / 12 / 6 / 3 h 24 / 12 / 6 / 3 h 24 / 12 / 6 / 3 h

Data processing NRT NRT NRT

Main problems

Forthcoming upgrades

• EOP– Dec 2004: recce in Bénin (Cotonou, Djougou) and Niger (Niamey),

installation of temp. GPS receiver in Cotonou (until Aug. 2005).

– March 2005: recce in Mali (Bamako, Gao, Tombouctou)

– June 2005: installation of temp. GPS in Djougou, Niamey, Gao

– Aug 2005: installation of AMMA GPS in Djougou, Niamey, Gao (incl. Met sensors Vaisala PTU200 + Inmarsat in Djougou and Gao).

– Dec 2005: replacement of Gao GPS receiver (many failures since 15 Sept. 05) and Niamey GPS receiver.

• SOP– March 2006: recce in Burkina-Faso and Ghana, construction of pillars

– April 2006: installation of AMMA GPS in Ouaga, Tamale, Tombouctou (incl. Met sensor) until end Oct 2006.

History of GPS network implementation

O. Bock Prepared for Leeds meeting, April 2006.

GPS station installed in Djougou, August 2005

Station enclosure

Sat. Link antenna

Solar panel

GPS antenna w. radome

Battery / charger

GPS receiver Sat. Link transmitter

Met sensor (PTU)

Met transceiver

Station enclosure

O. Bock Prepared for Leeds meeting, April 2006.

EOP

GPS station installed in Niamey, August 2005

GPS antenna w. radome

Station enclosureMet sensor

(PTU)

O. Bock Prepared for Leeds meeting, April 2006.

EOP

GPS station installed in Gao, August 2005

GPS antenna w. radome

Building top:

- Sat. Link antenna

Building room:

- GPS receiver

- Met transceiver

O. Bock Prepared for Leeds meeting, April 2006.

EOP

GPS site in Ouagadougou, March 2006

O. Bock Prepared for Leeds meeting, April 2006.

Concrete pillar for GPS antenna

Met enclosure

Ougadougou airport

SOP

GPS site in Tamale, March 2006

Concrete pillar for GPS antenna

O. Bock Prepared for Leeds meeting, April 2006.

Tamale airport

Met enclosure

SOP

GPS site in Tombouctou, March 2005

Tombouctou airport

Met enclosure

Concrete pillar for GPS antenna (built on 30 March 06)

SOP

• Raw AMMA GPS data archive:– Cotonou: 2004/12/03 - 2005/08/22 (Ashtech) with some gaps

– Djougou: 2005/06/04 - 07/20 (Ashtech), 2005/08/24 - 2006/02/27 (Trimble)

– Niamey: 2005/05/29 - 08/26 (Ashtech), 2005/08/26 - 12/17 (Trimble)

– Gao: 2005/06/11 - 08/28 (Ashtech), 08/29 - 09/16, 2005/11/03 - 2006/03/09 (Trimble)

• Data processed:– Standard processing strategy (GPS delay):

• Cotonou: 2005/01/01 - 08/22

• Djougou: 2005/06/04 - 07/20, 08/24 - 09/29

• Niamey: 2005/05/29 - 08/25

• Gao: 2005/06/11 - 08/27, 08/29 - 09/13

– Special processing strategy tests for dry-run period (GPS delay):• All avail. stations: 2005/08/15 - 09/15

– GPS IWV solutions available with Trimble receivers (incl. PTU)

Status on GPS data archiving and processing

O. Bock Prepared for Leeds meeting, April 2006.