GNSS Reprocessing Activities at swisstopo (LPT)...• Minor software adjustments to successfully manage GNSS data problems (we were confronted with in our operational analysis at LPT)

armasuisseSwiss Federal Office of Topography swisstopo

GNSS Reprocessing Activities at swisstopo (LPT)

S. Schaer, E. Brockmann, D. Ineichen

2 Swiss Federal Office of Topography swisstopo EUREF LAC Workshop, Nov 18-19, 2010, Warsaw, Poland

Reprocessing Network • Only one network will be reprocessed (with best possible options)• Reprocessing of all (+ additional; with names on plot) stations: max.

164 stations, 11 well-performing from EUREF, 34 additional sites (19 IGS, 25 EUREF, 9 RGP), all Swiss AGNES sites

• Processing of 11 private Swiss sites (2 sites starting October 2010)


Comment on LPT BSW V5.0+ and REPRO.PCF Design• GPSEST: GLONASS ambiguity resolution (SIGMA/QIF)

- Additional ambiguity verification (AMBVER) step for each baseline (up to 2000 km length)

• SNGDIF: “Bonus” option (to optimize selection/forming of short baselines)• MAUPRP performed in two modes (COMBINED/BOTH) depending on

baseline length• SW adjustment concerning antenna numbering (in order to guarantee

proper correction for PCV)• DEFXTR: Orbit fit verification• Minor software adjustments to successfully manage GNSS data problems

(we were confronted with in our operational analysis at LPT)• REPRO.PCF:

- Design according to latest CODE/PNAC standards- Many BPE variables- Data source (input/output): Bernese ZD and/or SD obs. files saved (!)- Start/end points- Final solutions computed for: GNSS, GPS-only, GLONASS-only (L/S)

• SINEX generation: NEQ SNX (minimum constraint w/o regularization)- Successful cross-check comparing multi-year ADDNEQ2 combination

using original daily (reduced) .NQ0 and SNX-derived .NQ0 files


Suspend Running BPE/PCF Processes

Excerpt of $U/PAN/PNAC.CPU:

SUSPEND_PCF 4

"AGNES.PCF_"

"AMET.PCF_"

"EUREF.PCF_"

"REPRO.PCF"

## widget = uniline

MSG_SUSPEND_PCF 1 "List of suspended PCF„

Note: Suspended BPE processes (active here for REPRO.PCF) immediately stop submitting waiting jobs (concerning BPE subprocesses).


GNSS Orbit Fitting Using ORBGEN V5.0 (Based on .TAB/.PRE File Information)


Daily Station Coordinate Repeatability of WTZR for GNSS, GPS, or GLONASS (for Year 2006)


Daily Station Coordinate Reproducibility of WTZR for GNSS, GPS, or GLONASS (for Year 2006)

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5D

aily

rep

rod

uci

bil

ity

(mm

)

GNSS 1.62 1.15 3.67

GPS 1.54 1.06 3.52

GLONASS 1.75 2.06 4.58

North East Up


Overall Daily Station Coordinate Reproducibility for GNSS, GPS, or GLONASS (for Year 2006)

0

1

2

3

4

5

6

7

8

9

10D

aily

rep

rod

uci

bil

ity

(mm

)

GNSS (137) 2.16 1.88 5.95

GPS (137) 1.95 1.77 6

GLONASS (15) 3.91 4.4 9.38

North East Up


3-Parameter Helmert Comparison of Yearly Station Coordinate Results (for Year 2006)

0

0.5

1

1.5

2

2.5

3

3.5

4M

ean

rm

s d

iffe

ren

ce (

mm

)

Zero-First Combination 0.1 0.1 0.1 0.1

GPS-GNSS 0.6 0.1 0.3 0.4

GPS-GLONASS 3.7 1.8 2.8 2.9

North East Up Total


Overall Daily Station Coordinate Reproducibility for GNSS, GPS, or GLONASS Using BASELINE and CORRECT Correlation Strategy (for 34% of 2006)

Correlation strategy: BASELINE

0

1

2

3

4

5

6

7

8

Dai

ly r

epro

du

cib

ilit

y (m

m)

GNSS 1.99 1.78 5.64

GPS 1.85 1.69 5.77

GLONASS 2.95 3.49 7.71

North East Up

Correlation strategy: CORRECT

0

1

2

3

4

5

6

7

8

Dai

ly r

epro

du

cib

ilit

y (m

m)

GNSS 1.59 1.45 4.67

GPS 1.58 1.44 4.67

GLONASS 2.59 3.21 7.02

North East Up


3-Parameter Helmert Comparison of Combined Station Coordinate Results Using BASELINE, or CORRECT Correlation Strategy (for 34% of 2006)

0

0.5

1

1.5

2

2.5M

ean

rm

s d

iffe

ren

ce (

mm

)

GNSS 1 0.5 1.4 1

GPS 0.4 0.4 1.4 0.9

GLONASS 0.7 0.7 2.1 1.4

North East Up Total


List of Items Relevant to Reprocessing

• RINEX observation database at LAC (as complete as possible)• Station information file containing consistent information (to be used as given for observation data

import!)• List of default station exclusions (due to known problems …)• Input products:

- GNSS orbits (including consistent SAT CRX information)- ANTEX/PCV information- ITRF CRD/VEL/FIX- BLQ table- GIM information (for QIF ambiguity resolution, or HOI correction)- P1-C1 GPS bias values (if required)- VMF1 coefficients (if required)

• Adequate computer hardware and updated software• Inclusion of GLONASS (GNSS/GPS/GLONASS) GPS+GLONASS=GNSS• Flexible reprocessing (BPE/PCF) scheme (for parallel session processing):

- BPE variables for most important processing options/parameters- Data source (input/output): Bernese ZD and/or SD obs. files saved (!)- Start/end points- Final solutions computed for: GNSS, GPS-only, GLONASS-only (L/S)

• SINEX export: NEQ SNX w/o regularization (containing best possible results)• Quality checks and optimizations concerning CPU time consumption (…)• Lesson to us: Additional setup of receiver antenna offset parameters wrt GLONASS


Outlook: New Options (1)

• GPSEST: Troposphere modeling: - Mapping function: NMF GMF VMF- Gradient model: TILTING TANZ

• GPSEST: Higher-order ionosphere (HOI) correction:- Three correction terms: second order, third order, ray bending/curvature term- Scaling factors with respect to each HOI correction term- Maps of VMF1 coefficients- Vienne grid files:

Atmospheric pressure loading Ocean non-tidal loading Hydrostatic pressure loading

• GPSEST: GLONASS ambiguity resolution (SIGMA/QIF/LAMBDA)• GPSEST: Interpolation of GNSS satellite clock offsets• GPSEST: Estimation of GLONASS clock offsets (enabling GLONASS-based PPP)• ORBGEN: Stochastic pulses (at 12 UT) / OTL CMC• SNGDIF: Bonus option (to optimize forming of short baselines)• MAUPRP: AUTO mode (concerning COMBINED/BOTH)• ADDNEQ2: More options concerning parameter pre-elimination

- Eliminate station parameters in case of equipment changes (receiver/antenna)- Eliminate parameters if “OUTSIDE_FROM_WINDOW”- Exceptions (following lists of station names)


Outlook: New Options (2)

• ATX2PCV (replacing PHCCNV): New ANTEX convertor. New PCV data format (supporting GNSS-specific corrections.

• FODITS (Find Outliers and Discontinuities in Time Series): New tool for analysis of (ADDNEQ2) .PLT time series results

• RNXSMT: Useful tool for pre-screening of pseudorange measurements for (pseudorange-based) Melbourne-Wübbena GPS ambiguity resolution

• BPE (Bernese Processing Engine): Reprocessing-specific options (separate campaign directory environment for each session automatically created/removed) and other useful features

• New satellite information file format• New station information file format (antenna numbering)• New (multi-GNSS) PCV file format (PHCCNV ATX2PCV)

Documents

GNSS Reprocessing Activities at swisstopo (LPT)...• Minor software adjustments to successfully manage GNSS data problems (we were confronted with in our operational analysis at LPT)