Transcript PowerPoint Presentation - 12.215 Modern Navigation

Using GLOBK and its Associated
Programs
OVERVIEW
• Basic types of analyses with globk
– Velocity and repeatability runs
• Programs in the GLOBK suite
– htoglb
– globk
– glred
– glist
– glsave
– hfupd
– glbtosnx
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Basic types of globk analyses
• Generally globk is used in two ways:
• Combining many years of data to generate velocities
solutions
• Analyzing groups of individual experiments to assess
position quality
• For example:
• After many years of processing, coordinate systems are
likely to change (eg., ITRF94 to ITRF2000) and globk can
bring all early results into a consistent frame
• Reason we write "loose" hfiles from gamit
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Create a .gdl file
• A gdl file is created by making a list of binary-hfiles. If
running from directory gsoln, then ls ../glbf/h*.glx >
india.gdl
• (.glr files are bias free solutions, .glx are bias fixed.
Sinex files are .gls)
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Globk velocity command file
• If multiple years of data, then try velocity solution
• globk command file must include
– apr_neu all 10 10 10 1 1 1
– where the 1 1 1 is velocity uncertainties in m/yr
– If velocity relative to specific site then add
– apr_neu iisc_gps 0.01 0.01 0.01 F F F
– would fix velocity of iisc
– Usually do not do this, but rather use glorg for
generalized definition
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glred
• To check the quality of the individual positions in the
hfiles we could create gdl files with just single hfiles
listed and run globk on each one using a command
file with
• apr_neu all 10 10 10 0 0 0
• apr_neu iisc_gps 0.01 0.01 0.01 0 0 0
• Again iisc is constrained and normal process
• Running globk on a set of individual hfiles is tedious
so we have a program that automatically does this:
glred
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glred
• glred is run the same way as globk ie.
– glred <crt> <prt> <log> <gdl file> <command file>
– but rather than combining all the data in the gdl
files, each file is processed separately by globk
• glred is a convenient way of making multiple globk
runs
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General format of gdl files
• General format of a gdl file is:
• [binary hfile name] <scale> <diagonal scale> <+>
• all except the file name are optional
• scale is a multiplier applied to the covariance matrix
• diagonal scale scales the diagonal (only used for
poorly conditioned sinex files)
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glred gdl file
• There are some options in the gdl file that add
flexibility to glred
• a + can be added at the ends of hfile name names so
that groups of hfiles will be combined eg.
•
•
•
•
../glbf/h991001_gps1.glx +
../glbf/h991002_gps1.glx
../glbf/h000601_gps1.glx +
../glbf/h000602_gps1.glx
• Would combine the first and second and third and
fourth files.
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glist
• To determine what is contained in a set of binary files
use glist
• glist <gdl file> <output_file> <sort_direction> [eq_file] [out
gdl] [apr file]
• Only first argument required
• adding eq_file will apply earthquakes and renames
• out_gdl is a time sorted gdl file which can be used in globk
• apr_file is an optional apr_file which the apr positions in the
binary hfiles will be compared to. Differences greater than
0.3 m are reported.
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glist
• During tutorial we will use this program to check
contents of local hfiles
• A grep 'P$' will extract a list of positions of the sites
and the duration of their use
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glist
• Allows solutions generated by globk to be saved as
binary hfiles
• Normally invoked in globk command file with the
• out_glb <name/structure>
• where name/structure is either:
– Expliciit name of file
– wild card constructor: Forms
– [email protected] will use the gdl file name replacing the first
letter and extent
– H------_SIO.GLX will use the 2-7 characters from the gdl
file name
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glsave
– if the com_file command was used in globk, then
glsave can be run as separate program
– glsave <com file> [out global name] [description]
<sol_file name>
– where com file is the name of the file given in
com_file command in globk
– out global name is name for output binary hfile
– description is string description enclosed in ' '
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glsave sol_file
• sol file name is an optional new solution file (not
usually used)
• Generated in glorg where the glorg solution file can be
output
• For example: with coordinate system definition applied
and constraints on nearby sites
• Advanced feature which should be carefully used.
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hfupd
• hfupd allow updates to be made to the binary hfile
files
• hfupd <options> <list of hfile names>
• Options include:
• -s <sinex file/station.info> name of new station.info or
sinex header file that contains new information about
sites (eg. correct antenna height)
• -e <edit file> file containing edited and renamed sites
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hfupd options
• -r report contents of station.info/sinex file
• -u update the hfiles (must given to actually update
files, without this option program reports changes to
be made but does change files)
• -p <hf/pmu_file> applied pole tide correction if
needed. uses either polar motion values in hfile or in
pmu_file
• other options are advanced features
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hfupd edit file
• Edit file contains lines of form
• EDIT
<NAME> <HF code> <Epoch range>
• deletes site NAME in hfile containing <HF code> in
name for period given by epoch range
• RESTORE <NAME> <HF code> <Epoch range>
• will restore a site provided not a combined binary file
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hfupd edit file
• RENAME <OLD NAME> <NEW NAME> <HF code>
<Epoch range>
• will rename a site from OLD to NEW
• Epoch range in form start (yr, mth, day, hr, min) end
(yr, mth, day, hr, min)
• start must before start of data in hfile and end must
after end of data in hfile
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glbtosnx
• SINEX (Solution independent exchange format) is
international standard for exchanging solutions of the types
contained in binary hfiles
• glbtosnx <dir> [-h] <comments file> <input binary hfile>
<output file name>
• dir is directory for name
• -h will write only headers and not full covariance matrix
• comments files is file containing comments (see
$HELP_DIR/head.snx
• output file name controls structure of generated file name
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General items
• Using ' ' for an input will often use a default value
• Called a place holder when specific input required
• glist file.gdl file.glist '' '' out.gdl
– will use default sort direction (+1) and no
earthquake file
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Creating apr_file
• apr_files are supplied in gg/templates
• They can be created from globk output with
– grep '^Unc. ' <prt/org file> | awk '{print substr($0,5)}'
>! new.apr
• Satellite ephemerides can be obtained with grep
'^Eph. '
• Programs plate and corcom can also be used to
generate apr files
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Summary
• Examined basic types of globk runs
• The external programs used with globk to
– List the contents of h-files
– Save combined h-files
– Run separate globk analyses
– Update hfiles with new information
– Convert h-files to SINEX files
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