ICELAND 2013 GPS Processing
TU Delft GRS fieldwork
Hans van der Marel, TU Delft
25 June 2013
Delft
University of
Technology
Challenge the future
GPS Processing Strategy
Three processing steps are foreseen
1. Data pre-processing (RINEXing & Q/C) of campaign data
2. IGS/EUREF Standards Ionosphere Free solution
•
•
•
Bernese GPS Software (V5.0)
Ionosphere free linear combination
Additional XX IGS stations included (fiducial stations)
IGS08(ITRF2008) Reference Frame
Enabler for absolute Troposphere Delay estimation
Downloaded from IGS Data Centers
•
Campaign data stored in local (ORX) directory
3. Analysis of the campaign solutions (time series)
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Motivation for Regional Network
• Network includes three types of stations
• Campaign stations (1-3 days of occupation)
• Local permanent stations (continuous operation during campaign, but
without good coordinates in ITRF)
• IGS/EPN stations with good station coordinates and velocities (!) in
ITRF2008 (IGS08).
• The main goals of adding regional IGS/EPN stations are
 To obtain the best possible site coordinates and position time series
in a global reference frame (ITRF2008)
 To obtain estimates of the atmospheric delay (Zenith Tropospheric
Delay) over the area of interest
 To verify the stability of presumed stable reference points (local
permanent stations)
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Bernese GPS Software 5.0
• Bernese software v5.0 developed by University of Berne
• Standard for IGS, EUREF and scientific campaign processing
• Semi-autonomous computation using Bernese processing engine
• Standard RNX2SNX script for Ionosphere free, Ambiguity Fixed,
Double Differenced Network Processing
• With some TU Delft additions
• Automatic FTP’ing of RINEX data and IGS orbits
• Analysis tools (Matlab)
• Wide experience (used at TU Delft since 1992)
• Latest version 5.0 including all modifications up to Oct 2012
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Main Steps involving the BSW5.0
1. Install the Bernese GPS software 5.0 (once)
a.
Install ActivePerl
b.
Install BSW5.0 using the TU Delft installer file
2. Setup the Campaign (once)
a.
Select IGS/EPN station to include in processing
b.
Prepare campaign directories and campaign files
3. Processing using the Bernese Processing Engine (BPE)
a.
Add campaign data (RINEX observation files) to ORX directory
b.
Update station information file(s) for the new stations (only if there
are new stations)
c.
Start the BPE
This step must be repeated every time there are new stations or data.
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Bernese Software BSW5.0
Desktop icons:
• Bernese 5.0 -> Start BSW5.0 GUI
• GPSDATA -> Campaign Directories
• GPSDATA/ICELAND/STA <- campaign definition files
• GPSDATA/ICELAND/ORX <- where to store campaign data
• GPSUSER -> User files (scripts, program options, etc)
Windows start menu
(extra link to documentation)
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BSW 5.0 GUI
Used later to set session/computation
date for the BPE
The BSW50 has a very
extensive help system
Quit the GUI
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Add ICELAND Campaign
1
1. Edit list of campaigns
2. Select active campaign
3. Create new campaign
3
2
(ignore warnings)
^Run creates the campaign
directories
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ICELAND Campaign Directory
GPSDATA/ICELAND/…
- Just created, except SAV…
- SAV you should create yourself
- Three important subdirectories:
ORX -> RINEX campaign data
STA -> Station definition files
SAV -> Where results are saved
- Others only hold temporary data
Data file locations:
- GPSDATA/ICELAND/ORX (campaign
data, RINEX observation files, no IGS
data, copy yourself)
- GPSDATA/CACHE (IGS station, orbit
and clockICELAND
data,2013
automatic
download
)
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Campaign Setup (manual task)
•
•
•
•
•
•
•
Add new campaign (ICELAND) <- just done
Select IGS/EPN fiducial sites (Network definition) <- next
Data center selection for IGS/EPN data (ICELAND.FTP)
Station Information File (ICELAND.STA)
Station Abbreviations File (ICELAND.ABB)
Plate Definition File (ICELAND.PLD)
A-priori Coordinate Files (IGS08.CRD, IGS08.VEL, IGS08.FIX)
• IGS08 (ITRF2008) coordinates and velocities for IGS/EPN stations =>
used as constraints (min constraint, 3 dof, shift in XYZ)
• A-priori coordinates for campaign stations from Precise Point
Positioning (PPP) and velocities from Nuvel-1A plate model
• Ocean Loading Parameter File (ICELAND.BLQ)
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Fiducial site selection (1)
• To obtain the best possible site coordinates in ITRF2008 we
should add as many as possible nearby IGS/EPN sites
• These are called fiducial sites
• Conflicting selection criteria
• More is better (averaging out of errors in fiducial coordinates and
processing errors)
• Distances should be with 1000 km (otherwise no simultaneous
observations, problems with ambiguity resolution, etc.). If necessary,
we could add some other permanent stations to bridge the distance.
• Fiducial sites should have good coordinates -> not all permanent
stations can be used (must be in ITRF).
• Only necessary for tectonic studies or studies which requires a
well defined and stable reference frame (in absolute sense)
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Fiducial site selection (2)
• Useful links
http://igscb.jpl.nasa.gov/network/complete.html
http://www.epncb.oma.be/_networkdata/stationmaps.php
• What to watch out for
• Use (at least) the same fiducials as in campaigns of previous years
• Check the station quality (using the web-links)
• IGS Reference frame sites are top of the line (used for definition of ITRF)
• Good tracking statistics
• If recent data is available (temporary outages, download problems)
• If the station has good coordinates in ITRF (several years of
observations, check relevant EPN pages)
• Receiver and antenna type (stations with similar receiver and antenna
types are a pro, good antenna calibrations are a must)
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Fiducial site selection (3)
http://www.epncb.oma.be/_networkdata/stationmaps.php
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Fiducial site selection for ICELAND
Used by campaigns in previous year:
Verify these yourself!
HOFN
http://igscb.jpl.nasa.gov/network/site/hofn.html (IGS reference frame site)
REYK
http://igscb.jpl.nasa.gov/network/site/reyk.html (data download problem)
Other IGS sites (to be included):
QAQ1
http://igscb.jpl.nasa.gov/network/site/qaq1.html (IGS reference frame site)
SCOR
http://igscb.jpl.nasa.gov/network/site/scor.html (IGS reference frame site)
NYA1
http://igscb.jpl.nasa.gov/network/site/nya1.html (IGS reference frame site)
TRO1
http://igscb.jpl.nasa.gov/network/site/tro1.html (IGS reference frame site)
MORP
http://igscb.jpl.nasa.gov/network/site/morp.html (IGS reference frame site)
Other EPN sites (candidates):
ARGI
http://www.epncb.oma.be/_networkdata/siteinfo4onestation.php?station=ARGI
No coordinates in ITRF2008, no velocities, not a fiducial, but
could be used to bridge the distance with MORP
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Campaign Setup (manual task)
•
•
•
•
•
•
•
Add new campaign (ICELAND) <- done
Select IGS/EPN fiducial sites (Network definition) <- just done
Data center selection for IGS/EPN data (ICELAND.FTP)
Station Information File (ICELAND.STA)
Station Abbreviations File (ICELAND.ABB)
Plate Definition File (ICELAND.PLD)
A-priori Coordinate Files (IGS08.CRD, IGS08.VEL, IGS08.FIX)
• IGS08 (ITRF2008) coordinates and velocities for IGS/EPN stations =>
used as constraints (min constraint, 3 dof, shift in XYZ)
• A-priori coordinates for campaign stations from Precise Point
Positioning (PPP) and velocities from Nuvel-1A plate model
• Ocean Loading Parameter File (ICELAND.BLQ)
We can now create the initial version of station
definition files in the ICELAND/STA
directory
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Processing
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Campaign definition files
• IGS08.CRD, IGS08.VEL and IGS08.FIX
• Download IGB08_R.CRD and IGB08_R.VEL from AIUB
(ftp://ftp.unibe.ch/aiub/BSWUSER50/STA), extract required fiducials,
and rename fiile to IGS08.CRD and IGS08.VEL
• Download ITRF2008.CRD and ITRF2008.VEL from AIUB [ibid],
extract REYK coordinates and velocities, add to IGS08.CRD|VEL
• Create IGS08.FIX with the list of fiducial stations (REYK is the only
non IGS reference frame station -> be alert later!)
• ICELAND.STA (Station information file)
•
Download IGS.STA from AIUB [ibid] and extract only the fiducial
stations we actually use
• ICELAND.PLD (same as IGS08.VEL, just copy)
• ICELAND.FTP
•
Each line contains first four character of file name (case sensitive)
and the data center from where to download the data from
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Campaign definition files (cont’)
• ICELAND.ABB (Station abbreviation file)
•
•
•
Contains 4 and 2 letter abbreviations for the stations
Can be created automatically by the BSW
But it is also easy to do by hand
• ICELAND.BLQ (Ocean loading tables)
•
•
•
Contains parameters to compute corrections for ocean loading
Ocean tide model: FES2004 (NO correction for CMC)
Parameters provided by Chalmers, Onsala (H.-G. Scherneck):
http://holt.oso.chalmers.se/loading/
•
Instead, we copied FES2004.BLQ from AIUB [ibid], and extracted
the required fiducial stations, and renamed to ICELAND.BLQ
Now all files are ready for processing the ficucial data.
IGS08.[CRD|VEL] and ICELAND.[STA|PLD|BLQ] have to be updated
for campaign data
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IGS08.CRD, IGS08.VEL, IGS08.FIX
You may consider removing REYK from the IGS08.FIX
file; this station is the only IGS non reference frame
station (but leave it in IGS08.CRD and IGS08.VEL)
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ICELAND.STA
Renaming of station names
Receiver, antenna, antenna height information
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IGS Receiver/Antenna types
Iceland
Station name
Receiver type
Antenna type
Dome
AntHgt
Location
HOFN 10204M002
LEICA GR25
LEIAR25.R4
LEIT
0.0319
Hoefn, Iceland
REYK 10202M001
LEICA GR25
LEIAR25.R4
LEIT
0.0570
Reykjavik, Iceland
MORP 13299S001
TRIMBLE NETR8
AOAD/M_T
NONE
0.0330
Morpeth, United Kingdo
NYA1 10317M003
TRIMBLE NETR8
ASH701073.1
SNOW
0.0000
Ny-Alesund, Norway
TRO1 10302M006
TRIMBLE NETR8
TRM59800.00
SCIS
0.0000
Tromsoe, Norway
QAQ1 43007M001
ASHTECH UZ-12
ASH701945E_M
SCIS
0.1206
Qaqortoq / Julianehaab
SCOR 43006M002
ASHTECH UZ-12
ASH701941.B
SCIS
0.1977
Scoresbysund/Ittoqqoor
(From ICELAND.STA)
UK / Norway
Greenland
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ICELAND.FTP
• All data is available from BKGI (BKG IGS)
data center
• In case you want to add for example ARGI
(or other EUREF EPN site) use BKGE (BKG
EUREF) as data center
• Other possibilities are CDDIS, IGN, …
• We don’t use this for campaign data =>
these are just copied into the ICELAND/ORX
directory
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ICELAND.BLQ
All these files are available
as in a zip file, just unzip
this to the STA directory.
Now everything is ready
for processing fiducial
stations
This is what we will do
next… using the BPE
Later we are going to add
campaign data, but not yet!
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Two ways of processing with BSW50
• The Bernese software consists of 60+ programs which
have to be run in a particular order.
• Sometimes the same program has to be run twice, or
even more, using different options and input data
• There are two ways to accomplish this
1. Through the GUI and menu system; you run the
individual programs. This offers the best flexibility, but
it is also very labour intensive and not recommended
for fist time users.
2. You use the Bernese Processing Engine (BPE)
using predefined settings and file naming conventions.
The BPE runs the programs in a particular order.
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Bernese Processing (BPE engine)
RNX2SNXA script (modified)
• IGS finial (rapid) orbits, clocks and ERP
• IGS RINEX data from various data centers
• Ionosphere models, Differential Code Biases (DCB) and Satellite
information (SATCRUX) files from University of Berne
• Absolute antenna calibrations from IGS/EPN;
• Elevation Cut-off of 3 degrees
• Elevation Dependent Weighting
• Ocean loading parameters from Chalmers/TUD
Processing time 5-10 minutes/day
Let try it on our newly defined ICELAND campaign
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Starting the BPE
1
2
1. Set session/computation date
2. Start BPE process
Should be ICELAND
Selected session/compute date
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Select session/computation date
Various date options
1
2
check
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Start BPE Process (1)
Press ^Next for
the next panel
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Start BPE Process (2)
Press ^Run to start the
BPE. That’s all (for now)
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Here we go !!
The BPE is running one
program after the
other, you can follow
the progress here…
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Oeps… ERROR
Another learning moment!
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What happened?
before
Protocol files: look here for errors,
especially the last file!!
after
Found!
Campaign directory
before and after
Temporary files (will be
deleted when successful)
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What happened?
• When there is an error, look into the campaign directory
• In case of an error, no files are deleted in the campaign directory,
so you will find all the program output
• In ICELAND/BPE you will also find the protocol files
• These are never deleted
• These are the first place to look for diagnostic messages
• Start with the last log-file: that is where the processing
stopped
In this case RNXGRA program is complaining about a file it
cannot find. This is because we did not update the Process
Control File (PCF) for the BPE: we’re using RNX2SNXA.PCF
with it’s default settings (probably for the I2GPS example…).
We need more education on the BPE and PCF files first …
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Process Control Files (PCF)
• GPSUSER contains the following subdirectories
GPSUSER/PCF
Process Control Files
GPSUSER/OPT
Directories with pre-set program options
GPSUSER/…
(others are not relevant for the BPE now)
• The Process Control Files can be found in GPSUSER/PCF
• The PCF we are using is RNX2SNXA.PCF
• Copy RNX2SNXA.PCF to ICELAND.PCF
(so we can safely make changes)
• Open ICELAND.PCF in an editor
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ICELAND.PCF (1)
After a lot of comments (explaining what is done) you find the
following section linking SCRIPTS to OPT directories with the
input parameters:
PID SCRIPT
OPT_DIR CAMPAIGN CPU
P WAIT FOR....
3** 8******* 8******* 8******* 8******* 1 3** 3** 3** 3** 3** 3** 3** 3**
3** 3**
#
# Copy required files and create a priori CRD file
# -----------------------------------------------001 R2S_FTP R2S_GEN
ANY
1
002 COOVEL
R2S_GEN
ANY
1 001
#
# Prepare pole, orbit, and clock information
# -----------------------------------------101 POLUPD
R2S_GEN
ANY
1 001
111 PRETAB
R2S_GEN
ANY
1 101
112 ORBGEN
R2S_GEN
ANY
1 111
(skipped)
You don’t need to change this part…
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ICELAND.PCF (2)
At the end of the file you find
the following section:
#
VARIABLE
8*******
V_A
V_B
V_C
V_E
V_F
V_MINUS
V_PLUS
V_CLU
V_STAINF
V_BLQINF
V_ABBINF
V_CRDREF
V_PCV
#
IGS means here final orbits
(available after 13 days), may
change this later into IGR for
rapid orbits (one day delay)
DESCRIPTION
40**************************************
A priori information
Orbit/ERP, DCB, ION information
Preliminary (ambiguity-float) results
Final (ambiguity-fixed) results
Size-reduced NEQ information
Session range begin (for COMPAR)
Session range end
Maximum number of files per cluster
Station information file name
Ocean loading correction file name
Station name abbreviation file name
A-priori/reference CRD/VEL/FIX filename
Absolute/relative PCV
DEFAULT
16**************
APR
IGS
P1_
F1_
R1_
-6
+0
3
I2GPS
ICELAND
I2GPS
IGS08
I08
ICELAND
Is blank, if you want ocean loading corrections
enter ICELAND here as well
Why we got the error…
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Start BPE Process (again)
Press ^Next to see next
input panel
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Enter name of PCF file here.
Use the ICELAND.PCF created
in the previous step
Press ^Next twice to see
the 4th input panel
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Here you can make some last minute
changes before starting the BPE (these
are not saved in the PCF for future runs)
IGS->IGR?
Press ^Run from any of
the BPE menu’s to start
the BPE.
Leave blank?
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Here we go again !!
The BPE is running one
program after the
other, you can follow
the progress here…
… fingers crossed
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SUCCESS !!
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Where are the results?
before
Protocol files
after
Results saved in ICELAND/SAV directory
Campaign directory
before and after
Temporary files deleted …
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What are the results?
Estimated Zenith Delays (troposphere)
Bernese format [F1|P1]_yyddd0.TRP
Troposphere SINEX F1_yyddd0.TRO
Protocol / Summary file (R2Syyddd0.PRC)
ADDNEQ output ([F1|P1]_yyddd0.OUT)
GPSEST output (ESTyyddd0.OUT)
SINEX (Solution Independent Exchange) file
Normal equations file [R1|F1|P1_yyddd0.NEQ
Coordinate files [F1|P1}_yyddd0.CRD
F1 Final Solution / P1 Provisional Solution
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Where are we now ?
• You have now successfully processed one day of data
• But only IGS stations were included…
… this makes little sense.
How do we add campaign data to the processing?
This is up next.
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Step 1: Conversion to RINEX
We use Trimble’s “Convert to Rinex” to convert T01 into RINEX.
There are a couple of issues to pay attention to:
• Marker name field : change s/n into the 4 letter code
• Marker number field: leave/make blank
• Receiver type: change “R7” into “TRIMBLE R7”, change “5700” into
“TRIMBLE 5700” (if you don’t do this the s/w will not recognize the
receiver
• Antenna offset: enter the antenna height (to ARP) you measured
• Antenna serial number: enter the serial number of the antenna
After conversion you have to rename the RINEX files
• Change s/n into 4 letter code, e.g. 06681740.13o -> KVIH1740.13O
• Use all uppercase letters (not kvih1740.13o but KVIH1740.13O)
Copy/move RINEX observation files to GPSDATA/ICELAND/ORX
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Step 2: Update campaign files (1)
When there are new stations we have to update the campaign
definition files IGS08.CRD, IGS08.VEL, ICELAND.STA, ICELAND.ABB
and ICELAND.BLQ.
We could do this all by hand (using an editor) and results from e.g. a
PPP run with NRCAN’s web-service.
We can also do this by doing PPP (Precise Point Positioning) run
using the BPE in the BSW50:
• Open the BPE (after selecting a date) and select in the 2nd panel
the PPPA Process Control File
• In the 4th panel you leave the STAINFO and BLQ input fields blank.
Also check whether to use IGS (final) or IGR (rapid) products.
• Press ^Run to start the BPE.
The BPE will now process all RINEX observation files (in ORX) for the
selected day using the PPPA.PCF.
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Step 2: Update campaign files (2)
When the BPE/PPPA has finished, it has:
•
•
•
•
Created IGS08_U.CRD and IGS08_U.VEL in the STA directory
Updated ICELAND.ABB in the STA directory
Create a SINEX file PPP_____.SNX in the SOL directory
Saved other output in the SAV/… directories
IGS08_U.CRD is an update of IGS08.CRD whereby coordinates for
new stations have been added (only for stations which did not exist
previously). IGS08_U.VEL contains the new stations with zero
velocities : we will be using zero velocities for all campaign stations,
resulting in coordinates at the epoch of measurement!
If you are happy with the IGS08_U.[CRD|VEL] updates you
use these to replace the IGS08.[CRD|VEL] that is used in the
RNX2SNXA processing.
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Step 2: Update campaign files (3)
The BPE/PPPA script has also updated the abbreviation tables in
ICELAND.ABB (STA directory). No action is needed here.
Next we have to update the ICELAND.STA information file
• We left the STAINFO field blank in the BPE/PPPA, so that the
RINEX file was not checked against the station information file
• This is not allowed for the BPE/RNX2SNXA script; the STAINFO file
is an essential step in checking the RINEX files
A easy way to update the ICELAND.STA file is
• In the Bernese GUI, select conversion > sinex to station information
• Select the SINEX file PPP_____.SNX created by the BPE/PPPA
run, select an output file (e.g. UPDATE.STA) and enter a title,
then enter ^Run.
This will extract information from the SINEX file.
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Step 2: Update campaign files (4)
Now you can merge the output of UPDATE.STA with ICELAND.STA.
When doing this:
• Check that the collected information is correct, if necessary
correct the information. Doing this now will save you a lot of work
later.
• Change the start and end times for the stations
The final item on the list is to update the Ocean Loading tables in
ICELAND.BLQ.
• Open ICELAND.BLQ in an editor, copy the a block for one of the
campaign stations, and rename the station name
• The ocean loading effect is the same for all campaign stations
(You could also decide to do without ocean loading corrections in the BPE/RNX2SNXA by leaving
the entry for BLQ files blank)
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Step 3: Run the BPE/RNX2SNXA
Now you restart the network processing including the campaign data.
A few point to pay attention to:
• Check that you are using the ICELAND.PCF (which is our tailored
version of RNX2SNXA.PCF)
• Decide if you will be using final IGS products (IGS) or rapid products
(IGR). Final products are only available after 13 days; rapid products
will only remains available for a few days after finals.
• If you have a BLQ file no not leave the BLQ field blank (you won’t have
ocean loading corrections then…)
• Check the protocol files that the stations have actually been included
and that the processing results are ok.
• Don’t loose your patience, things may not go directly your way…
Good luck!
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Further reading
• README.TXT that came with the Windows installer
Has some good hints on setting up a new campaign, and the steps
needed to include new stations
• The on-line help system available from the GUI
This is an excellent source of information (one mouse click away)
• The Bernese manual (pdf)
Has lots and lots of information, available from BERN50 directory.
Contains also very good information on GPS (and Glonass) in general.
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