AMMA - GPS networkO. BockPrepared for Leeds meeting, April 2006.Status of implementation on April 1st 2006
O. Bock, IPSL/SA, France
GPS team and support teamsGPS science team:Olivier Bock (IPSL/Service dAronomie, CNRS, Paris, France) Marie-Noelle Bouin (IGN/LAREG, Marne-la-Valle, 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, IRDBnin: mainly IRD - CotonouNiger: mainly IRD - NiameyMali: IRD - Bamako, ASECNA and DNM - Gao and TombouctouBurkina-Faso: IRD - Ouaga, CNRST, EIER,Ghana: Met. Service in Tamale and AccraO. BockPrepared for Leeds meeting, April 2006.
EOPGaoNiameyDjougouInstalled (temp) (AMMA) (replaced)June 05 (GPS)Aug 05Dec 05June 05 (GPS)Aug 05Dec 05June 05 (GPS)Aug 05
EquipementGPS + PTUGPS + PTUGPS + PTUTelecomInmarsatInmarsatData transfert freq.Daily: Jan 06 -NRT plannedDaily: Jan 06 -Data processing1 - 2 month latencyNRT planned1 - 2 month latencyMain problems- GPS recv breakdown (Sept 05, Mar 06)- Inmarsat unreliableNo telecom connexion until April 06- Power shortage (nearly no data lost)- Inmarsat unreliableForthcoming upgrades- GPS recv to be replaced in April 06April 06: VSAT connexion and data transfert- Data transfert in failure since 27 Feb. 06
SOPTombouctouOuagadougouTamaleInstalled (SOP)April 06April 06April 06EquipementGPS + PTUGPS + PTUGPS + PTUTelecomGSMGSMGSMData transfert freq.24 / 12 / 6 / 3 h24 / 12 / 6 / 3 h24 / 12 / 6 / 3 hData processingNRTNRTNRTMain problemsForthcoming upgrades
History of GPS network implementationEOPDec 2004: recce in Bnin (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, GaoAug 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.SOPMarch 2006: recce in Burkina-Faso and Ghana, construction of pillarsApril 2006: installation of AMMA GPS in Ouaga, Tamale, Tombouctou (incl. Met sensor) until end Oct 2006.O. BockPrepared for Leeds meeting, April 2006.
GPS station installed in Djougou, August 2005Station enclosureSat. Link antennaSolar panelGPS antenna w. radomeBattery / chargerGPS receiverSat. Link transmitterMet sensor (PTU)Met transceiverStation enclosureO. BockPrepared for Leeds meeting, April 2006.EOP
GPS station installed in Niamey, August 2005GPS antenna w. radomeStation enclosureMet sensor (PTU)O. BockPrepared for Leeds meeting, April 2006.EOP
GPS station installed in Gao, August 2005GPS antenna w. radomeBuilding top:- Sat. Link antennaBuilding room:- GPS receiver- Met transceiverO. BockPrepared for Leeds meeting, April 2006.EOP
GPS site in Ouagadougou, March 2006O. BockPrepared for Leeds meeting, April 2006.Concrete pillar for GPS antennaMet enclosureOugadougou airportSOP
GPS site in Tamale, March 2006Concrete pillar for GPS antennaO. BockPrepared for Leeds meeting, April 2006.Tamale airportMet enclosureSOP
GPS site in Tombouctou, March 2005Tombouctou airportMet enclosureConcrete pillar for GPS antenna (built on 30 March 06)SOP
Status on GPS data archiving and processingRaw AMMA GPS data archive:Cotonou: 2004/12/03 - 2005/08/22 (Ashtech) with some gapsDjougou: 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 - 08/22Djougou: 2005/06/04 - 07/20, 08/24 - 09/29Niamey: 2005/05/29 - 08/25Gao: 2005/06/11 - 08/27, 08/29 - 09/13Special processing strategy tests for dry-run period (GPS delay):All avail. stations: 2005/08/15 - 09/15GPS IWV solutions available with Trimble receivers (incl. PTU)O. BockPrepared for Leeds meeting, April 2006.