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You are provided with the original raw file (35222360.t01) and log sheet
(6908_2014-236.pdf) from the occupation of a survey mark, during which the
tripod was disturbed. This experiment demonstrates how to use track to find the
epoch of disturbance and truncate the RINEX file to prevent propagation of bad
data during data exchange and other processing.

All executable commands have a dollar symbol ($) as the first character.


1. Translate Trimble raw file to RINEX

 a. Run runpkr00

$ runpkr00 -g -adeimv 35222360.t01 69082360
$ ls 69082360*

 b. Run teqc

$ teqc +nav 69082360.14n +obs 69082360.14o -tr d 69082360.dat
$ ls 69082360*

   Note that this raw files covers more than one day, from 2014-08-24T21:31:00
   to 2014-08-26T00:06:00.


2. Find the approximate position and a nearby continuous site

$ teqc +qc -nav 69082360.14n 69082360.14o

   Read 69082360.14S and view in Google Earth. You will find that the site is
   located just off a frontage road parallel to I-680 in northern California.
   This area has many continuous GNSS sites in the Plate Boundary Observatory
   (PBO) network, so look for nearby sites at http://pbo.unavco.org/. You will
   find that P261 is the nearest site, about 9 km to the west. We will therefore
   use P261 as our reference site.


3. Download RINEX files for the reference site and IGS final orbits

$ sh_get_rinex -archive unavco -yr 2014 -doy 236 -ndays 3 -sites p261
$ sh_get_orbits -orbit igsf -yr 2014 -doy 236 -ndays 3 -nofit

   Concatenate the files into one for input to track

$ teqc -phc p2612360.14o p2612370.14o p2612380.14o +obs p261236-80.14o
$ cat igs18070.sp3 igs18071.sp3 igs18072.sp3 > igs18070-2.sp3


4. Create a basic track command file

 a. Define input RINEX files

$ cat << END > track.cmd
 obs_file
  p261 p261236-80.14o F
  6908 69082360.14o   K

END

 b. Define input orbit files

$ cat << END >> track.cmd
 nav_file igs18070-2.sp3 SP3

END

 c. Define the type of experiment ("long" for baseline length > 1 km)

$ cat << END >> track.cmd
 mode long

END

 d. Define a priori coordinates (from .apr-file or sh_rx2apr) and constraints

$ cat << END >> track.cmd
 site_pos
  p261 -2677432.92612 -4248806.23641  3918882.09941   -0.01961    0.01519    0.00248 2011.4110
  6908 -2669573.2959  -4253294.9698   3919133.7752

 site_stats
  6908  0.01 0.01 0.01  1 1 1

END

 e. View log sheet to calculate equipment configuration and antenna height

Receiver: Trimble R7 ("C"-type from ~/gg/tables/rcvant.dat)
Antenna:  Trimble Zephyr Geodetic 2 (IGS code TRM57971.00; see
          ftp://igs.org/pub/station/general/antenna.gra or
          https://www.ngs.noaa.gov/ANTCAL/ for dimensions)

Information for P261 may be obtained from the master station.info file for the
dates to be processed:

$ grep '^ *P261' ~/gg/tables/station.info

Antenna height is:

$ echo '133.50 133.55 133.80' | awk '{slbgp=($1+$2+$3)/3; dhbgp=sqrt(slbgp^2-16.981^2); dharp=dhbgp+4.111-8.546; printf "%.4f\n",dharp/100}'
$ cat << END >> track.cmd
 ante_off
  p261  0.0000 0.0000 0.0083  TRM29659.00     SCIT  C
  6908  0.0000 0.0000 1.2810  TRM57971.00     NONE  C

 antmod_file ~/gg/tables/antmod.dat

END

 f. Add some explicit controls on input data and output files

$ cat << END >> track.cmd
 interval 30

 use_gptgmf 0.5

 back_type smooth

 pos_root 6908
 res_root 6908
 sum_file 6908.sum

 out_type DHU

END


5. Run track and plot results

$ track -f track.cmd >& track.log
$ sh_plot_track -f 


6. Finally, truncate the RINEX file to remove bad data

$ teqc -e +nav 69082360.14n +obs 69082360.14o -tr d 69082360.dat

  Michael Floyd (2018-06-05, MIT; last updated 2018-06-21, MIT)

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