From Yoaz.Bar-Sever at jpl.nasa.gov Thu Nov 11 08:22:42 2010 From: Yoaz.Bar-Sever at jpl.nasa.gov (Yoaz Bar-Sever) Date: Thu, 11 Nov 2010 09:22:42 -0700 Subject: [IGSMAIL-6298] Reprocessed IGS Trop Product now available with Gradients Message-ID: Authors: Yoaz Bar-Sever and Sung Byun Dear Colleagues: We'd like to announce the availability the reprocessed IGS tropospheric product. The reprocessed product is based on IGS reprocessed orbit and clock from 1995 to 2007. The reprocessed product, and all products going forward from 2007 now include estimates of the North and East delay gradients, in addition to the zenith path delay. The only other change to the estimation approach was the replacement of the Niell mapping function with GMF. A summary of the estimation approach is provided below. While retaining the naming convention of the trop product files, the format has been expanded slightly to accommodate the addition of gradients, hopefully in a transparent manner: The "SOLUTION_FIELDS_1" line of the Header now specify the gradient fields. For example: +TROP/DESCRIPTION *KEYWORD______________________ VALUE(S)______________ SAMPLING INTERVAL 300 SAMPLING TROP 300 ELEVATION CUTOFF ANGLE 7.0 TROP MAPPING FUNCTION GMF SOLUTION_FIELDS_1 TROTOT STDDEV N_GRAD STDEV E_GRAD STDEV -TROP/DESCRIPTION The main body of the file which contains data now looks as follows (eg, for ALGO site on 2010-123): +TROP/SOLUTION *SITE EPOCH_______ TROTOT STDEV N_GRAD STDEV E_GRAD STDEV ALGO 10:123:00000 2421.4 1.9 -4.634 3.733 -0.861 2.125 ALGO 10:123:00300 2421.3 1.9 -4.614 3.692 -0.883 2.106 ALGO 10:123:00600 2421.5 1.8 -4.541 3.617 -0.793 2.091 ALGO 10:123:00900 2421.8 1.7 -4.490 3.539 -0.527 2.069 ALGO 10:123:01200 2421.9 1.7 -4.508 3.456 -0.397 2.035 Note that all units are in mm. These files are available at both JPL and CDDIS sites. At JPL: ftp://sideshow.jpl.nasa.gov/pub/igs_trop/trop_zpd/repro1/yxxxx (from 1995 to 2007) ftp://sideshow.jpl.nasa.gov/pub/igs_trop/trop_zpd/yxxxx (from 2008 to present) At CDDIS: ftp://cddis.gsfc.nasa.gov/pub/gps/products/troposphere/zpd/repro1/xxxx (from 1995 to 2007) ftp://cddis.gsfc.nasa.gov/pub/gps/products/troposphere/zpd/xxxx (from 2008 to present) With this reprocessing we now have 15 years of consistently derived trop products from hundreds of sites. Summary of estimation approach: Fixed orbits and clocks: IGS Final Re-Analyzed Combined (1995-2007), and IGS Final Combined 2008-Current Earth orientation: IGS Final Re-Analyzed Combined (1995-2007), and IGS Final Combined (2008-Current) Transmit antenna phase center map: IGS Standards Receiver antenna phase center map: IGS Standards Elevation angle cutoff: 7 degrees Mapping function (hydrostatic and wet): GMF A priori delay (m): hyd = 1.013*2.27*e -0.116*ht wet = 0.1 Data arc: 24 hours Data rate : 5 minutes Estimated parameters: station clock (white noise), station position, wet zenith delay (3 cm/hour random walk), delay gradients (0.3 cm/hour random walk), phase biases (white noise) Contact Sung Byun <byun at jpl.nasa.gov> or Yoaz Bar-Sever <Yoaz.E.Bar-Sever at jpl.nasa.gov> with any question -------------- next part -------------- An HTML attachment was scrubbed... URL: http://igscb.jpl.nasa.gov/pipermail/igsmail/attachments/20101111/80ec6dc1/attachment.html