10.71

Release 10.71 consolidates incremental updates made since release 10.70 of June 2018 and completes modifications to GAMIT following recommendations for the IGS’s repro3. Significant changes of which most users should be aware are:

  • The radiation pressure model is expanded from 9 to 13 parameters, adding two twice-per-revolution (2/rev) and two 4/rev terms. GAMIT will carry all 13 parameters, designated ECOMC (for Empirical CODE Models 1 and 2 combined) in tables/sestbl. In generating fits to the IGS orbits, we recommend using ECOMC (the default). Note that if you estimate orbits in GAMIT (RELAX. in tables/sestbl.) you cannot mix in GLOBK the 10.71 processing with pre-10.71 processing that uses the 9-parameter (BERNE or ECOM1) models. When combining regional processing with MIT or SIO global h-files, you should always run GAMIT without orbit estimation (BASELINE in tables/sestbl.), as we have long recommended. Even with the same version, different choices of orbit modeling parameters are likely to make the MIT combined binary-files incompatible with recently processed. If BASELINE model is used in the GAMIT processing, the incompatibilities will be minor but in RELAX mode they can be severe (high \(\chi^2\) increments). Removing all apr_svs, mar_svs, apr_rad and mar_rad options in the GLOBK command file should minimize the effects of incompatibilities.

  • Beidou processing now uses L6/C6 (B3 at 1268.53 MHz) rather than L7/C7 (B2b at 1207.140 MHz) as the lower-frequency observable to accommodate the tracking configuration of most of the current GNSS receivers providing public data. Based on a sampling of 230 RINEX files from the archives, about 50% include only L6/C6 compared with about 5% that include only L7/C7. The higher-frequency observable will remain L2/C2 (B1-2 at 1561.098 MHz) since very few of the public RINEX files contain L1/C1 from the B1 at 1575.42 MHz transmitted by BDS-3 satellites. If L7/C7 is the only observable present (i.e., no L6/C6), GAMIT will try to process the data along with L7/C7 receivers but there may be ambiguity resolution issues. Users should assess data files and process together only those sites with the same frequency data. There are still some issues with clock estimates for Beidou data and pre-fit editing in autcln.

  • The default tables/sestbl. now has the 2nd-order ionosphere model turned on. The IGSG IONEX files will be used by default. If processing near-real time, the -ion igrg option should be used with sh_gamit. We also recommend always including the Inertial Reference System option (current default IAU0A) explicitly.

  • tables/svnav.dat is now linked to the IGS satellite metadata SINEX file (igs_metadata.snx). Release 10.70 and earlier versions of GAMIT cannot read this file format and svnav.dat needs to be linked to svanv.dat.allgnss, which will be maintained for the foreseeable future. Several changes to files in the tables/ directory may be incompatible with early versions of GAMIT.

  • The tables/station.info file now accommodates another optional column (AntDAZ in the header line) to specify the azimuth (clockwise from true north) of the antenna. Conventionally antennas are aligned with true north but some (and likely many others that we don’t know about yet) are recorded as set to another azimuth. The AntDAZ azimuth is read to rotate the phase center offsets (PCOs) and phase center variations (PCVs) from the ANTEX file (tables/antmod.dat) to correct for the azimuth of the antenna. sh_upd_stnfo can extract this information from IGS log files if the AntDAZ header is included (users should ensure that there are no non-numeric values in the columns below AntDAZ; white space in OK). The IGS will not implement this feature until ITRF2020 is released (that is, it will be part of repro3 but not the operational processing).

  • We have changed many symbolic links in tables/ to be relative, rather than absolute, which assume that users install a local GRIDS/ directory at the same level as the source code (e.g. gamit/, libraries/, kf/, maps/, tables/, etc.), where grids downloaded from ftp://everest.mit.edu/pub/GRIDS/ should be stored. Creation of specific symbolic links, e.g. atml.grid, map.grid, met.grid, by the user to the corresponding grid files is then no longer necessary.

  • sh_gamit now will remake g-files from SP3 files each time it is run to ensure that the orbit models in tables/sestbl. are consistent with the sh_sp3fit models (these models are now read from sestbl. provided a copy can be found in the standard processing directories). For sub-network processing, g-files should be made once before proceeding to process each sub-network (assumed to be in parallel) using the -remakeg N option used with sh_gamit.

  • We remind users that when processing GLONASS data the ambiguity free (.glr) binary h-files should be used in GLOBK. Also remember that a multi-GNSS orbit file should be used as well.

  • The format for the apr_svs and mar_svs radiation parameters specification in the GLOBK command file has changed, with the unused zrad and xrad entries removed (see Pre 5.32 and Post 5.32 discussion in ~/gg/help/globk.hlp). The options using the <nn.nn>R format remains unchanged. Older globk commands with explicit radiation parameter constraints and process noise may need to be updated.

  • GLOBK has moved to using <GNSS><SVN>_<PRN> syntax for satellite identifiers in output files (e.g. the .org file), where <GNSS> is G, R, E or C, and <SVN> and <PRN> are Satellite Vehicle Number and Pseudo-Random Noise code, respectively. For GPS, the default is still PRN<PRN>_<SVN>. The new format for GPS can be invoked with the use_prn n command near the top of the command file. (See ~/gg/help/globk.hlp.)

  • New wild card features in file names now allow dates and times to be used based on the date and time of the h-file being processed. (See 5.32 features in ~/gg/help/globk.hlp.)

  • GLOBK can now do reference frame realization in back solutions. This will happen automatically if glorg is invoked in a GLOBK command file with the bak_file option included.

  • We will no longer provide GMT .grd files in the maps/ directory to reduce the size of the archive (.tar) files. Instead we now provide a new script, sh_dem, which will download and create a local copy of a chosen digital elevation model (DEM) over a geographic region, both selected using the script options. The script is now called by sh_plotvel if the -topo, -topo_file and/or -illu_file options are used; if the latter is given without an argument, sh_plotvel will create a .grd file of the gradient for plotting shaded-relief (illumination) from the topographic .grd file named or created with the -topo_file option. Both sh_dem and sh_plotvel require GMT to run.

  • GMT version 6.0.0 was released in November 2019. Scripts in com/ that use GMT to produce plots were updated for GAMIT/GLOBK 10.6 to accommodate major changes in the syntax of GMT version 5 commands (see relnote.10.6); the old scripts, using GMT 4 syntax, are still available in com_preGMT5/ but are no longer maintained. Although we have not done extensive testing yet, we understand that GMT 6 is fully backwards compatible with GMT 5 and should work seamlessly with our scripts currently in com/, which explicitly call gmt (now the sole GMT executable) throughout.

  • We have become aware that the GMT installation available via the software repository for Ubuntu 16.04 LTS does not include the supplemental programs, most significantly psvelo for GAMIT/GLOBK. We recommend upgrading your Ubuntu operating system or building GMT from source. See https://gmt.soest.hawaii.edu/projects/gmt/wiki/Installing#Linux and our “Known Issues” web page for more information.

  • We have also become aware that there seems to be an issue with the implementation of gfortran version 7 on at least Ubuntu 18.04 LTS and openSUSE Leap 15.1 operating systems, resulting in failed compilation with segmentation fault error messages, including See <file:///usr/share/doc/gcc-7/README.Bugs> for instructions. We recommend upgrading to another version of gcc/gfortan, or downgrading to gcc/gfortran version 6. See our “Known Issues” web page for more information.

Summary of specific changes (by directory)

com/

links.arc, links.com, links.day

  • Updated to link otides.dat and to avoid linking the old ephemeris files (soltab., luntab., nutabl.) if ~/gg/tables/nbody exists.

  • Fixed typos.

sh_cleanup

  • Added missing closing curly bracket in test to remove n-files on lines 386 and 387. Floyd/Pickle 190507

sh_gamit

  • Revert to using GPS-only RINEX 2 instead of MGEX RINEX 3 nav files when processing GPS data since sh_rx2apr (svpos/svdiff) doesn’t yet recognize RINEX 3.

  • Fix bug in naming files for -jclock sp3 option.

  • Fixed a typo in call to sh_setup causing the lfile. not to be updated from the .apr file.

  • Correct version number - now 10.70 2019/8/14.

sh_get_orbits

  • Placed $noclean variable in quotes in if-test at end to ensure a string match rather than interpretation as a test, which causes an error.

sh_glred

  • Removed debug statement that forced archiving of the binary h-files.

sh_hector

  • Minor edits to some awk commands.

sh_makex

  • Initialize the $sp3file variable to avoid a problem when running stand-alone.

sh_otlcmc
sh_plot_elmean

  • Updated color scheme to work with GMT 5. Small changes to line widths.

sh_rx2apr

  • Updated grep commands to select only records that begin with a space before the site ID, ignoring any EXTENDED records that may be in the .apr file.

sh_sp3fit

  • Fix bug in writing model names for the arc input file.

sh_tshist

  • Updated script to fully implement pos_res type. Original only partially updated from com_pre5GMT/ version.

sh_upd_stnfo (and kf/htoglb/mstinf.[fh])

  • Added -debug option to help diagnose problems with bad year in IGS logfiles and fixed a bug associated with first antenna starting after the first receiver entry.

sh_update_dcb

  • Added explicit internal test for presence of tables/svnav.dat, needed for gamit/utils/dcbtab2.

sh_update_eop

  • Updated to circumvent the shutdown of maia.usno.navy.mil and toshi.nofs.navy.mil from 2019-10-24 to 2020-04-30.

gamit/

orbits/kouba_gps.f, orbits/oversn.f; arc/ertorb.f, arc/earthradTUM.f, arc/aversn.f; lib/gpsblock.f, lib/lversn.f

  • Updated for Block IIIA SV. WARNING: Will recongize GPS Block IIIA but use IIF values for Earth radiation pressure and yaw.

arc/satprop.f, arc/earthradTUM.f

  • Updated for Block III SV.

  • Temporarily use IIF Earth radiation model for Block IIIA for NCLE1 (set for TUM1) and remove debug print from earthradTUM.f.

arc/sbfn

  • Fix bug in effect of General Relativity on satellite (~ 8 mm over 24 hrs).

includes/makex.h, lib/rrinex.f

  • Increase maximum line length to 1024, and associated maximum observables allowed in rrinex.f and MAXOBT in makex.h to 63, to accommodate long records in RINEX 3 files.

lib/clkera

  • Erroneous extra read of clkoff, apparently a problem with Intel compiler but not gfortran.

lib/linear.f, model/get_antinfo.f, model/get_antpcv.f, model/get_svantpcv.f

  • Fix problem with interpolation of elevation-only PCVs.

lib/rrxhed.f

  • Skipped reading of SV-dependent wavelength factors in a RINEX header since this feature is not yet supported.

lib/sel_obtyp.f

  • Fix problem with omitted Beidou observable.

  • Remove debug print statements.

makex/get_navclk.f

  • Fix bug in not recognizing GNSS code “I” on the nav file.

makex/getsp3.f

  • Added test for sp3d format.

makex/rbatch.f

  • Add trap for numsit > maxsit in new-format case.

  • Correct fix of trap for numsit.

makex/mversn.f, model/j_from_sp3.f, model/getnav.f

  • Allow reading sp3 “d” and fix getting the program name for warning/fatal messages.

makexp

  • Assign the SP3 file name when running manually.

  • Revoked Zou/King 180912 update and reverted to version 9.86.

  • Added correct handling of SP3 file name when running manually.

model/call_mag.f, model/iondel.f, model/mag13.f, model/setup.f; fixdrv/bmake.f; tables/sestbl.

  • Added IGRF13 magnetic field model and changed default from IGRF12 to IGRF13.

model/setup.f

  • Fix frequency check so that it works for L1-only.

model/update_coords

  • Add missing “debug” in call to get_antinfo.

utils/metutil

  • Change linear interpolation routine to be scalar rather than vector.

help/

displace.hlp

  • Updated documentation.

kf/

blsum/tscon.f

  • Added assumption that UNR/NGL .txyz2 files without a reference frame explicitly in the file name are the latest IGS14 version.

displace

  • Updated Makefile, grid calculations and added tensile component to calculations.

gen_util/name_to_block.f

  • Changes BLOCK III to BLOCK IIIA so that correct satellite number is assigned to the new PRN03.

gen_util/real_stats.f

  • Updated dimensioning and bounds checking. Very long time series could cause segmentation violations.

gen_util/sp3_lib.f, includes/sp3_def.h

  • Updated maximum number of nadir angles values and added a dimensioning test.

gen_util/sp3_lib.f

  • Fixed bug in report_stat call that is invoked in updated sp3_def.h is not used.

  • Increased max nadir values to 41 for Galileo chamber calibrations.

globk/read_glb_mar.f

  • Critical update needed to make the SOURCE command work.

glout/write_iers.f

  • Updated formats to allow more than 99 reference frame sites.

htoglb/mstinf.[fh] (and com/sh_upd_stnfo)

  • Added -debug option to help diagnose problems with bad year in IGS logfiles and fixed a bug associated with first antenna starting after the first receiver entry.

track, gen_util/sp3_lib.f

  • Updated for Beidou B7 phase and range measurements.

utils/corcom

  • Updated output formats to allow for fast ice velocities.

utils/glbtog.[fh]

  • Fixed bugs with writing G-files for non-GPS systems.

libraries/

comlib/proper_runst.f

  • Removed need for trailing “/” in HELP_DIR definition.

tables/

luntab.2020.J2000, soltab.2020.J2000, nutabl.2020

  • Added luni-solar tables for 2020 from JPL DE200.

antmod.dat

  • Now linked to an IGS14 rather than IGS08 ANTEX file, which is no longer updated by the IGS for new launches. As noted in relnote.10.61, this will create a 2–3 mm discontinuity in height for all antennas and 5–10 mm discontinuities in horizontal and height for about 20 antennas.

  • Updated regularly to the latest IGS14 ANTEX file (currently igs14_2091.atx, as of the date of this release).

  • Linked from 2019-10-10 (GPS week 2074) onwards to the IGS14 ANTEX file supplemented with calibrations provided by the National Geodetic Survey (NGS) (currently ngs14_2091.atx), plus some additional entries copied from similar records to accommodate antennas without any official calibrations. tables/antmod.dat is linked to tables/ngs14_2091_plus.atx, at the time of this release.

  • Updated GLONASS SVs R801, R802, R855, R856, R858 and R859 to match extended IGS designations (K1A, K1B and M+) in tables/igs_metadata.snx.

igs14_comb_na17.apr

  • Added new North America plate reference frame (“NA17”) based on Kreemer et al. [2018].

ftp_info

  • Updated vmf1 address and directory according to change reported by Johannes Boehm in IGS-ACS email #1176.

  • Added HartRAO IGS regional data center and JAXA data center.

globk.cmd

  • Added inclusion of apr_tran by default and option for apr_rot when using SINEX files.

  • Corrected erroneous COMB out_glb output file name to ensure ------ string is parsed properly by prepending H to file name.

leap.sec

  • Extended limit of table to 31 December 2020 with no additional leap seconds, following to IERS Bulletin C 59.

hi.dat

  • Added TRM159800.00 antenna.

igs_metadata.snx

  • Added from http://mgex.igs.org/ (currently igs_metadata_2091.snx, as of the date of this release) and augmented with a bespoke block for the yaw of each satellite, currently read from tables/svnav.dat with some assumptions for some satellites and systems.

rcvant.dat

  • Fully updated to match IGS codes for all receivers and antennas, following ftp://igs.org/pub/station/general/rcvr_ant.tab.

  • Records of other known antennas, from the old rcvant.dat and those in the NGS ANTEX file (see description of antmod.dat, above), are added.

  • The 14th character, indicating support for the receiver or antenna in GAMIT, is updated to identify the source of antenna calibration. See header for more information.

svnav.dat

  • Metadata for GLONASS (R), Galileo (E), Beidou (C), IRNSS (I) and QZSS (J) fully updated to match tables/igs_metadata.snx (from http://mgex.igs.org/), which will ultimately supercede tables/svnav.dat; metadata for GPS assumed to be good (will be verified ultimately).

otlcmc.dat

  • Replaced the provisional center-of-mass corrections for FES2012 with new official ones from H. G. Scherneck. The differences are less than 0.05 mm.

References

[1]

Corné Kreemer, William C. Hammond, and Geoffrey Blewitt. A robust estimation of the 3-D intraplate deformation of the North American plate from GPS. Journal of Geophysical Research: Solid Earth, 123(5):4388–4412, 2018. doi:10.1029/2017JB015257.