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RTPPPMode / ConfiguringPPPMode

PPP configuration file

The file “GpsPppFilelocations.cfg” in the “Analysis/Configuration/” directory of the installation directory contains the information about where to download the PPP correction files. For example:

% **** these are the escape strings for inserting into file names % $4w = 4 digit week % $1d = 1 digit day of the week % $2h = 2 digit hour of day 00-23 % $4y = 4 digit year % $3d = 3 day of year % $2y = 2 digit year % ****************************** SP3 data, includes orbit and clock *************************** % final SP3 orbit and clock (about 13 days) Def=SP3 Latency=17280 file=cddis.gsfc.nasa.gov/gps/products/$4w/igs$4w$1d.sp3c.Z file=garner.ucsd.edu/pub/products/$4w/igs$4w$1d.sp3c.Z file=igs.ensg.ign.fr/pub/igs/products/$4w/igs$4w$1d.sp3c.Z file=igscb.jpl.nasa.gov/pub/product/$4w/igs$4w$1d.sp3c.Z Compression = Z EndDef

% rapid SP3 orbit and clock (17 hours) Def=SP3 Latency=800 file=cddis.gsfc.nasa.gov/gps/products/$4w/igr$4w$1d.sp3c.Z file=garner.ucsd.edu/pub/products/$4w/igr$4w$1d.sp3c.Z file=igs.ensg.ign.fr/pub/igs/products/$4w/igr$4w$1d.sp3c.Z file=igscb.jpl.nasa.gov/pub/product/$4w/igr$4w$1d.sp3c.Z Compression = Z EndDef

% ultra rapid SP3 orbit and clock (real time) Def=SP3 Latency=0 file=cddis.gsfc.nasa.gov/gps/products/$4w/igu$4w$1d_$2h.sp3.Z file=garner.ucsd.edu/pub/products/$4w/igu$4w$1d_$2h.sp3.Z file=igs.ensg.ign.fr/pub/igs/products/$4w/igu$4w$1d_$2h.sp3.Z file=igscb.jpl.nasa.gov/pub/product/$4w/igu$4w$1d_$2h.sp3.Z Compression = Z EndDef

% ****************************** Ionospere delays, Ionex format *************************** % final ionospere (about 11 days) Def=Ionex Latency=14000 file=cddis.gsfc.nasa.gov/gps/products/ionex/$4y/$3d/igsg$3d0.$2yi.Z file=igs.ensg.ign.fr/pub/igs/iono/$4y/$3d/igsg$3d0.$2yi.Z Compression = Z EndDef

%rapid ionospere (under 24 hours) Def=Ionex Latency=720 file=cddis.gsfc.nasa.gov/gps/products/ionex/$4y/$3d/igrg$3d0.$2yi.Z file=igs.ensg.ign.fr/pub/igs/iono/$4y/$3d/igrg$3d0.$2yi.Z Compression = Z EndDef

%Real time ionospere (and a maximum of about 4 days) Def = Ionex Latency = 0 file=ftp.unibe.ch/aiub/CODE/COPG$3d0.$2yI.Z Compression = Z EndDef

The format is similar to the video output configuration file, and follows the following syntax:

  • Any lines starting with a % are ignored, and can be used for comments.
  • Each section of the definition file starts with a “Def=” and is completed with “EndDef”:
Def =DefinitionType
Object=ObjectValue
Object=ObjectValue
Object=ObjectValue
Object=ObjectValue
Object=ObjectValue
EndDef
  • There are current 2 types of definition : “SP3” and “Ionex”
  • Within each definition the following objects are allowed:
Latency. This allows the user to configure how long it is before the file becomes available for download. The time is in units of minutes. For example: if the file is available immediately then “Latency=0”. If the data is available 1 day afterwards, then Latency=1440 (60 minutes x 24 hours). Note that this value is checked before the system attempts to download the file, so it is good practice to make it a little optimistic. For example if the file should be available 24 hours later, it may be wise to set this to just 20 hours. If the file cannot be accessed as it not yet available, the system will simply download the file with a lower latency setting – so apart from a short delay caused by trying to access a file that is not available, this doesn’t cause any problems.
File. (Note that up to 10 alternative file locations can be listed in the definition.) This is the place where the file can be accessed formatted as a standard URL. Note that as the files are typically located on UNIX servers, case is important! The directory and file names are typically dependent on the date/time that the data applies to, and so to enable targeting the correct file there are current 6 “escape sequences” that can be used in the URL, these are:
$4w = 4 digit week
$1d = 1 digit day of the week
$2h = 2 digit hour of day 00-23
$4y = 4 digit year
$3d = 3 day of year
$2y = 2 digit year
Compression. There is currently only 1 type of compression supported “Unix Z deflation”. If the file requires decompression the set “Compression=Z” otherwise simple omit this line or enter “Compression=None”.

Finally note that the file is file is processed in the order it is written, so:

  • Enter data with the greatest latency first. If the system determines that the data won’t be available yet, it will continue to the next and check the latency of this etc. If a definition with a “latency=0” is entered first then this would be used every time and the higher accuracy data never applied.
  • Enter the files in the definition in the order you want them accessed. If there is a particular site that seems to download quicker then it would make sense to put this site first. If one of the sites is repeated causing connection problems, then it would make sense to put this last in the list.
Page last modified on August 30, 2012, at 02:20 PM