1. AMMA - GPS network O. BockPrepared for Leeds meeting, April 2006. Status of implementation on April 1 st 2006 O. Bock, IPSL/SA, France

2. 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. BockPrepared for Leeds meeting, April 2006.

3. Summary(1/2) EOP GaoNiameyDjougou 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 Telecom Inmarsat Data transfert freq. Daily: Jan 06 -NRT plannedDaily: Jan 06 - Data processing 1 - 2 month latencyNRT planned1 - 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

4. Summary(2/2) SOP TombouctouOuagadougouTamale Installed (SOP)April 06 EquipementGPS + PTU TelecomGSM Data transfert freq.24 / 12 / 6 / 3 h Data processingNRT Main problems Forthcoming upgrades

5. 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. BockPrepared for Leeds meeting, April 2006.

6. GPS station installed in Djougou, August 2005 Station enclosure Sat. Link antenna Solar panel GPS antenna w. radome Battery / charger GPS receiverSat. Link transmitter Met sensor (PTU) Met transceiver Station enclosure O. BockPrepared for Leeds meeting, April 2006. EOP

7. GPS station installed in Niamey, August 2005 GPS antenna w. radome Station enclosure Met sensor (PTU) O. BockPrepared for Leeds meeting, April 2006. EOP

8. GPS station installed in Gao, August 2005 GPS antenna w. radome Building top: - Sat. Link antenna Building room: - GPS receiver - Met transceiver O. BockPrepared for Leeds meeting, April 2006. EOP

9. GPS site in Ouagadougou, March 2006 O. BockPrepared for Leeds meeting, April 2006. Concrete pillar for GPS antenna Met enclosure Ougadougou airport SOP

10. GPS site in Tamale, March 2006 Concrete pillar for GPS antenna O. BockPrepared for Leeds meeting, April 2006. Tamale airport Met enclosure SOP

11. GPS site in Tombouctou, March 2005 Tombouctou airport Met enclosure Concrete pillar for GPS antenna (built on 30 March 06) SOP

12. 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. BockPrepared for Leeds meeting, April 2006.