GPS World, August 2009

THE ALMANAC predictions GPS performance assessments anomaly impact analysis GPS FAQs and other services to meet the needs of GPS users in the field The 2nd Space Operations site offers constellation status scheduled outages user advisories almanac data electronic mail and downloadable files For more information Questions and anomaly reports from civilians and industry contact Navigation Information Service see previous listing DOD associated activities only e mail gps_ support@ schriever af mil 746 Test Squadron GPS Information Archive https gpstest 46tg af mil webpub general bbstest nsf The 746 Test Squadron based at Holloman Air Force Base in New Mexico provides archived almanac data in SEM36 and YUMA formats and a special almanac detailing the short GPS week observed range errors as viewed from the GPS Satellite Reference Station at Holloman Air Force Base constellation status and user advisories Information dates back to 1992 and is available 24 hours a day The site also will soon offer links to the GPS Test Center of Expertise legacy databases For more information Michael P Brown phone 505 679 2863 e mail michael brown@ 46tg af mil U S National Geodetic Survey NGS GPS Orbit Information www ngs noaa gov The U S National Geodetic Survey NGS of the National Oceanic and Atmospheric Administration manages the National and Cooperative CORS Continuously Operating Reference Station network This network currently contains more than 1400 GPS data collection sites in the United States and its territories with a few in foreign countries NGS provides free access to GPS data from these sites via the Internet CORS sites are operated by a collection of more than 186 organizations representing various federal state local and foreign government agencies as well as various academic and commercial institutions The CORS network enables GPS users to determine centimeter level positional coordinates for user selected locations CORS data serves to monitor crustal motion the distribution of moisture in the atmosphere and the distribution of free electrons in the ionosphere NGS also provides the Online Positioning User Service OPUS This web based utility enables users to submit static GPS data for automatic processing with relevant CORS data Within minutes after receiving a users data OPUS returns computed positional coordinates for the location associated with the data NGS recently released OPUS RS Rapid Static that will return a solution for as little as 15 minutes of data whereas OPUS requires at least two hours of data The National Geodetic Survey will serve as the IGS Analysis Center Coordinator for a period of four years starting on January 1 2008 NGS will coordinate the activities of several international geodetic organizations in producing high precision GNSS orbits For more information Contact NGS at ngs cors@ noaa gov or call Rick Foote at 301 713 3205 ext 152 U S Naval Observatory http tycho usno navy mil gps html The U S Naval Observatory USNO provides GPS timing data and status information For more information Contact Wendy Kelley phone 202 762 1455 or DSN 762 1455 email wendy kelley@ usno navy mil International International GNSS Service IGS http igscb jpl nasa gov ftp igscb jpl nasa gov http igscb jpl nasa gov organization centers html The foundation of IGS is a global network of more than 350 permanent continuously operating geodetic quality GPS and GPS GLONASS sites The station data are archived at four global data centers and six regional data centers Ten analysis centers regularly process the data and contribute products to the analysis center coordinator who produces the official IGS combined orbit and clock products Timescale ionospheric and tropospheric products are analogously formed by specialized coordinators for each The IGS reference frame coordinator determines tracking site coordinates and velocities from analysis centers solutions and organizes the IGS contribution to the International Terrestrial Reference Frame ITRF The IGS Central Bureau is responsible for day to day management of the IGS following policies set by the IGS International Governing Board as well as for communication and outreach The IGS intends to integrate future GNSS signals such as Galileo into its activities as demonstrated by the successful incorporation of GLONASS For more information Contact International GNSS Service Central Bureau Jet Propulsion Lab MS 238 540 Pasadena CA 91109 USA phone 818 354 2077 fax 818 393 6686 email igscb@ igscb jpl nasa gov Australia Geoscience Australia www ga gov au Geoscience Australia is Australias national agency for geoscience research and geospatial information It maintains a comprehensive website Users can download data from the Australian Regional GPS Network and view graphs of data quality and time series of positions An online GPS processing service AUSPOS allows users to upload dual frequency Rinex data and receive computed ITRF positions rapidly by e mail Within Australia these ITRF positions are also transformed to the Geocentric Datum of Australia The site provides information about Australian coordinates datums and transformations Geoidellipsoid separations for the region can be downloaded or computed on line For more information Contact Geoscience Australia phone 61 2 6249 9111 fax 61 2 6249 9929 e mail geodesy@ ga gov au Europe Czech Republic http radio fel cvut cz satnav ftp polaris fel cvut cz pub almanac The Czech Technical University Faculty of Electrical Engineering Department of Radio Engineering in Prague Czech Republic offers historical constellation status and almanac data for both GPS and GLONASS systems For more information E mail service administrators at puricep@ feld cvut cz or seidl@ feld cvut cz or contact Frantisek Vejrazka vice rector of the Czech Technical University Technicka 2 166 27 Prague 6 Czech Republic phone 420 2 2435 2246 fax 420 2 3333 9801 e mail vejrazka@ feld cvut cz Denmark www kms dk Kort og Matrikelstyrelsen National Survey and Cadastre Denmark provides GPS raw carrier phase data by request and maintains the following services NAV DK and Code corrections distributed by way of cellular telephony These services are based on the permanent reference station network for GPS operated by the National Survey and Cadastre Denmark For more information Contact Casper Jepsen or Bo Hansen Kort and Matrikelstyrelsen Rentemestervej 8 DK 2400 Copenhagen NV Denmark phone 45 72 54 50 00 fax 45 35 87 50 51 e mail kms@ kms dk GPS World August 2009 www gpsworld com 48