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armasuisseSwiss Federal Office of Topography swisstopo

Overview of Relevant GNSS Biases

Stefan Schaer

Swiss Federal Office of Topography (swisstopo) / CODE@AIUB

2Swiss Federal Office of Topography swisstopoKolloquium Satellitennavigation, TU München, 21. Mai 2012

Workshop on GNSS Biases 2012 (www.biasws2012.unibe.ch)

37 participants on 18 January 2012 in front of the main building of the University of Bern, Switzerland

Presentations available at:www.biasws2012.unibe.ch

GNSS biases?

• A prominent example is: GPS group delays (TGD) as broadcast by the GPS.

• Parameters that might be considered as nuisance (or bias) parameters, such as- ionosphere,- troposphere,- antenna,- clock,

have in fact a physical meaning (and are useful for particular applications).

• Our main focus is on: biases with respect to specific GNSS observables.

List of GNSS biases

• GNSS differential code biases (DCB)• CODE’s DCB specialties (e.g., DCB multiplier estimation)• GLONASS interfrequency code biases (relevant to GNSS

clock estimation, or PPP)• Intersystem code biases• “DCPB” crucial for GLONASS ambiguity resolution• Intersystem phase biases (or drifts)• Uncalibrated phase delays (UPD) relevant to undifferened

integer fixing for PPP• GLONASS-GPS station-specific intersystem translations as

considered in CODE’s GNSS analysis• IGS ANTEX model• (GPS) quarter-cycle issue (again crucial)

List of GNSS biases

Receiver classification• The following code (pseudorange) observables are available from GPS:

C/A (=C1), P1(Y1), P2(Y2), and C2 (for the Block IIR-M constellation).• In the presence of Anti-Spoofing (AS), P-codes P1, P2 are encrypted for

non-authorized users to Y1, Y2. • We have to distinguish between three receiver classes (in terms of the

code tracking technology):- P1/P2: C1, P1, P2- C1/X2: C1, X2=C1+(P2-P1) - C1/P2: C1, P2

• C1/X2 receiver models are identified as cross-correlation (CC) receivers. Prominent examples are Rogue and Trimble 4000 models.

• The operation of CC receivers depends on the AS state. It is assumed here that AS is always on (!).

• The latest generations of Leica, Novatel, Trimble receivers belong to the C1/P2 receiver class (at least in terms of GPS).

Instrumental code biases

• Instrumental biases, BC1, BP1, BP2, BC2, are present with respect to C1, P1, P2, C2. These biases are not accessible (in the absolutesense).

• It is common to address the following differences of code biases:- P1-P2,- P1-C1, and- P2-C2 differential code bias (=DCB).

• By convention, precise satellite clock corrections contain a specific linear combination of P1 and P2 satellite biases, specifically the ionosphere-free LC: 2.55·BP1-1.55·BP2(+B0).

• It is obvious that code tracking data from both the C1/X2 and the C1/P2 receiver class must be corrected in order to achieve full consistency with P1/P2 data, or precise satellite clock information.

• Non-separability: satellite and receiver biases are generally not separable.

How to Use P1-P2 and P1-C1 Satellite DCB Information

The following table gives the corrections due to satellite-specific P1-P2 and P1-C1 DCB values for the most important linear combinations derived from various combinations of code observable types:

Single-freq.

ClockIono.

Amb. res.

Determination methods:• P1-P2: Iono. / Abs. receiver cal.• P1-C1: Diff. / Clock / Amb. res.

CODE’s GPS/GLONASS P1-P2 DCB monthly solution, computed for December 2011

CODE’s GPS P1-P2 DCB monthly solution, computed for December 2011

CODE’s GLONASS P1-P2 DCB monthly solution, computed for December 2011

GNSS global ionosphere map (GIM) information as derived by CODE

GNSS P1-P2 DCB retrieval affected by solar cycle

CODE’s GPS P1-C1 DCB monthly solution, computed for December 2011 (as provided to IGS)

GPS receiver classes commonly distinguished:

P1/P2: C1 P1 P2C1/P2: C1 P2C1/X2: C1 X2

Indirect and direct GPS P1-C1 DCB determination (1/3)

P1/P2: C1 P1 P2C1/P2: C1 P2C1/X2: C1 X2

Indirect and direct GPS P1-C1 DCB determination (2/3) indirect

P1/P2: C1 P1 P2C1/P2: C1 P2C1/X2: C1 X2

Indirect and direct GPS P1-C1 DCB determination (3/3) direct

Direct GNSS DCB estimation for P1-C1 and P2-C2 based on RINEX data• P1-C1 and P2-C2 observation differences are analyzed file by file

(typically station by station for a particular day) and stored for:- overall combination- combinations may be actually recalled/retrieved for:

selected receiver typesselected receiver groupsall considered receivers/stations (=overall combination)

• Sophisticated outlier detection scheme using quantities responding to IQR (interquartile range IQR=Q0.75-Q0.25) just one scalar quantity to be selected to cope with observation data with most various noise levels and characteristics, respectively

• Overall (LS) combination performed (with an outlier detection scheme concerning station-specific, or file-specific DCB determinations)

CODE’s GNSS P1-C1 DCB monthly solution, computed for December 2011 (directly from RINEX)

CODE’s GPS P1-C1 DCB monthly solution, computed for December 2011 (directly from RINEX)

CODE’s GLONASS P1-C1 DCB monthly solution, computed for December 2011 (directly from RINEX)

CODE’s GNSS P2-C2 DCB monthly solution, computed for December 2011 (directly from RINEX)

CODE’s GPS P2-C2 DCB monthly solution, computed for December 2011 (directly from RINEX)

CODE’s GLONASS P2-C2 DCB monthly solution, computed for December 2011 (directly from RINEX)

Statistics on GNSS DCB reprocessing from RINEX

List of GNSS biases

Verification of receiver tracking technology using the Bernese Software

================================================================================PART 6: VERIFICATION OF RECEIVER TRACKING TECHNOLOGY================================================================================

STATION NAME MULTIPLIER RMS ERROR SUGGESTED RECEIVER TYPE GIVEN RECEIVER NAME / TYPE MATCH----------------------------------------------------------------------------------------------------------------

BRUS 13101M004 -G -0.224 0.043 P1/P2 5.242 28.666 ASHTECH Z-XII3T P1/P2 OKFFMJ 14279M001 -G -0.105 0.051 P1/P2 2.045 21.578 JPS LEGACY P1/P2 OKMATE 12734M008 -G 0.874 0.048 C1/X2 2.637 18.312 TRIMBLE 4000SSI C1/X2 OKONSA 10402M004 -G -0.104 0.041 P1/P2 2.536 26.943 ASHTECH Z-XII3 P1/P2 OKPTBB 14234M001 -G -0.124 0.048 P1/P2 2.579 23.352 ASHTECH Z-XII3T P1/P2 OKVILL 13406M001 -G -0.062 0.044 P1/P2 1.404 24.048 ASHTECH Z-XII3 P1/P2 OKZIMJ 14001M006 -G 0.057 0.048 P1/P2 1.195 19.598 JPS LEGACY P1/P2 OKZIMM 14001M004 -G 1.131 0.047 C1/X2 2.788 24.083 TRIMBLE 4000SSI C1/X2 OK

Excerpt of a PPP BPE processing summary file (PPP03139.PRC):

How to Use P1-P2 and P1-C1 Satellite DCB Information

The following table gives the corrections due to satellite-specific P1-P2 and P1-C1 DCB values for the most important linear combinations derived from various combinations of code observable types:

Single-freq.

ClockIono.

Amb. res.

List of GNSS biases

AC GLONASS bias files collected for comparison (GPS weeks 1666-1667)• COD Center for Orbit Determination in Europe, AIUB, Switzerland

- Bernese DCB• EMR Natural Resources Canada, Canada

- no GLONASS bias information (GLONASS biases ignored in GNSS clock analysis)

• ESA European Space Operations Center, ESA, Germany- bias-SINEX (first two days of GPS week 1666 missing)

• GFZ GeoForschungsZentrum, Germany- bias-SINEX

• GRG GRGS-CNES/CLS, Toulouse, France- modified Bernese DCB

• IAC Information-Analytical Centre, Russia- PBS format

• JPL Jet Propulsion Laboratory, USA- GIPSY time dependent parameter format (wrong weeks)

Station 1

Satellite 1 Satellite 2

Station 2 Station 3

Datum definition for GLONASS biases (1)

Station 1

Station 2 Station 3

Station 1 Station 2 Station 3

Satellite 1 Satellite 2 Satellite 3 Satellite 4

Station 1 Station 2 Station 3

Satellite 1 Satellite 2 Satellite 3 Satellite 4

AC GLONASS bias comparison:COD-ESA (1)

AC GLONASS bias comparison:COD-ESA (2) sign changed

AC GLONASS bias comparison:COD-ESA (3) P1-C1 DCB corrected

Summary of AC GLONASS biascomparison

AC Median (ns) Mean (ns) Std (ns)

COD-ESA 0.01 0 0.79

COD-GFZ 0.02 0 1.33

COD-GRG 5.63 1.87 23.12

ESA-GFZ 0.01 0 1.34

ESA-GRG 4.14 1.29 20.63

GFZ-GRG 6.00 1.72 25.23

Summary and conclusion

• Best agreement (smallest std) could be achieved for thecomparison between COD and ESA- with an overall std of 0.79 ns- resulting in a single-AC std of 0.56 ns

• Only 24 constants were necessary to compensate for theGLONASS bias datum definition specific to each AC

List of GNSS biases

GPS-GLONASS receiver clock offsets (when using GPS/GLONASS broadcast clock information), computed for days 009, 010, 011 of year 2012 (1/3)

List of GNSS biases

Single-difference ambiguity bias term• Illustration of the single-difference (SD) ambiguity bias term,

as introduced by Habrich (1999), to be proportional to the single-difference ambiguity initialization bias (and proportional to the GLONASS frequency channel difference i–j):

Illustration of SD bias term (1/2)

SD ambiguity bias 1 (cycles)

Illustration of SD bias term (2/2)

GNSS ambiguity resolution at CODE

• Up to 6000km (3000km in a first POD step): Melbourne-Wübbenawidelane and narrowlane ambiguity resolution restricted to GPS only

• Up to 2000km: Quasi-Ionosphere-Free (QIF) L1&L2 AR for GPSand for GLONASS SD ambiguities with the same frequency channel numbers

• Up to 200km: Phase-based widelane AR for GPS and GLONASS, with retrieval of GLONASS SD ambiguity initialization biases; narrowlane AR for GPS and GLONASS1 considering the previously extracted SD bias values

• Up to 20km: Direct L1&L2 AR for GPS and GLONASS(1), retrieval of GLONASS SD ambiguity initialization biases

• New: Ambiguity verification (AMBVER) BPE processing step

1Self-calibrating ambiguity resolution step

Ambiguity resolution summary (e.g. AMB113030.SUM):================================================================================AMBIGUITY RESOLUTION (L1&L2)================================================================================

File Sta1 Sta2 Length Before After Res Sys Max/RMS L1 Receiver 1 Receiver 2(km) #Amb (mm) #Amb (mm) (%) (L1 Cycles)

----------------------------------------------------------------------------------------------------------------------0AMT3030 MAT1 MATE 0.011 114 1.5 4 1.5 96.5 G 0.121 0.025 TRIMBLE 4000SSI LEICA GRX1200GGPRO #AR_L120JT33030 THU2 THU3 0.000 148 0.8 0 0.8 100.0 G 0.044 0.005 JPS LEGACY ASHTECH UZ-12 #AR_L120KUO3030 UNBJ UNBN 0.000 168 0.5 6 2.8 96.4 G 0.252 0.055 TPS LEGACY NOV OEMV3 #AR_L120KUO3030 UNBJ UNBN 0.000 102 0.5 0 2.8 100.0 R 0.043 0.014 TPS LEGACY NOV OEMV3 #AR_L120KUO3030 UNBJ UNBN 0.000 270 0.5 6 2.8 97.8 GR 0.252 0.044 TPS LEGACY NOV OEMV3 #AR_L120KUU3030 UNBJ UNBT 0.000 100 0.6 0 0.8 100.0 G 0.090 0.015 TPS LEGACY TPS NETG3 #AR_L120KUU3030 UNBJ UNBT 0.000 100 0.6 0 0.8 100.0 R 0.034 0.011 TPS LEGACY TPS NETG3 #AR_L120KUU3030 UNBJ UNBT 0.000 200 0.6 0 0.8 100.0 GR 0.090 0.013 TPS LEGACY TPS NETG3 #AR_L120LUO3030 UNB3 UNBN 0.000 172 0.7 5 3.0 97.1 G 0.258 0.059 TRIMBLE NETR5 NOV OEMV3 #AR_L120LUO3030 UNB3 UNBN 0.000 100 0.7 0 3.0 100.0 R 0.056 0.016 TRIMBLE NETR5 NOV OEMV3 #AR_L120LUO3030 UNB3 UNBN 0.000 272 0.7 5 3.0 98.2 GR 0.258 0.048 TRIMBLE NETR5 NOV OEMV3 #AR_L120SIK3030 IRKJ IRKT 0.004 128 1.2 0 1.3 100.0 G 0.083 0.020 JPS LEGACY ROGUE SNR-8000 #AR_L120WM43030 CRAR MCM4 1.089 154 5.2 2 5.2 98.7 G 0.113 0.017 TPS ODYSSEY_E ASHTECH UZ-12 #AR_L120YJO3030 JOZ2 JOZE 0.084 108 1.4 4 1.5 96.3 G 0.083 0.021 LEICA GRX1200GGPRO TRIMBLE 4000SSI #AR_L12CG0T3030 CAGL CAGZ 0.003 96 1.3 0 1.4 100.0 G 0.134 0.021 TRIMBLE 4700 TPS E_GGD #AR_L12DGD33030 DGAR DGAV 0.000 96 0.6 0 0.6 100.0 G 0.013 0.003 ASHTECH UZ-12 JPS EGGDT #AR_L12FAFI3030 FAIR FAIV 0.038 160 1.6 0 1.7 100.0 G 0.049 0.015 ASHTECH UZ-12 JPS EGGDT #AR_L12FR0L3030 FRDN UNB3 2.332 112 1.9 1 2.1 99.1 G 0.110 0.023 TPS NETG3 TRIMBLE NETR5 #AR_L12FR0L3030 FRDN UNB3 2.332 100 1.9 0 2.1 100.0 R 0.072 0.021 TPS NETG3 TRIMBLE NETR5 #AR_L12FR0L3030 FRDN UNB3 2.332 212 1.9 1 2.1 99.5 GR 0.110 0.022 TPS NETG3 TRIMBLE NETR5 #AR_L12GUUG3030 GUAM GUUG 18.678 84 15.9 4 18.2 95.2 G 0.341 0.122 ASHTECH UZ-12 TRIMBLE NETR5 #AR_L12HAHR3030 HARB HRAO 2.066 94 2.6 0 2.8 100.0 G 0.100 0.022 ASHTECH UZ-12 ASHTECH UZ-12 #AR_L12HM073030 HERS HERT 0.136 102 1.0 4 1.1 96.1 G 0.042 0.010 SEPT POLARX3ETR LEICA GRX1200GGPRO #AR_L12HM073030 HERS HERT 0.136 110 1.0 0 1.1 100.0 R 0.193 0.030 SEPT POLARX3ETR LEICA GRX1200GGPRO #AR_L12HM073030 HERS HERT 0.136 212 1.0 4 1.1 98.1 GR 0.193 0.023 SEPT POLARX3ETR LEICA GRX1200GGPRO #AR_L12KKK43030 KOKB KOKV 0.000 90 0.5 0 0.6 100.0 G 0.020 0.005 ASHTECH UZ-12 JPS EGGDT #AR_L12MJKM3030 MOBJ MOBK 0.000 120 0.6 0 0.7 100.0 G 0.006 0.001 JPS LEGACY JPS EGGDT #AR_L12MJKM3030 MOBJ MOBK 0.000 116 0.6 0 0.7 100.0 R 0.022 0.004 JPS LEGACY JPS EGGDT #AR_L12MJKM3030 MOBJ MOBK 0.000 236 0.6 0 0.7 100.0 GR 0.022 0.003 JPS LEGACY JPS EGGDT #AR_L12MS0B3030 METS METZ 0.001 146 1.0 0 1.1 100.0 G 0.039 0.012 ASHTECH Z-XII3 JPS EUROCARD #AR_L12O20E3030 OHI2 OHI3 0.003 144 1.2 2 1.2 98.6 G 0.041 0.008 JPS E_GGD LEICA GRX1200GGPRO #AR_L12O20E3030 OHI2 OHI3 0.003 128 1.2 0 1.2 100.0 R 0.094 0.017 JPS E_GGD LEICA GRX1200GGPRO #AR_L12O20E3030 OHI2 OHI3 0.003 272 1.2 2 1.2 99.3 GR 0.094 0.013 JPS E_GGD LEICA GRX1200GGPRO #AR_L12P3P43030 PBR2 PBRI 0.012 100 1.2 4 1.2 96.0 G 0.149 0.020 LEICA GRX1200+GNSS LEICA GRX1200+GNSS #AR_L12PMPH3030 PIMO PTAG 11.789 100 12.4 10 13.9 90.0 G 0.347 0.098 ASHTECH UZ-12 LEICA GRX1200GGPRO #AR_L12S2ZI3030 ZIM2 ZIMM 0.019 76 1.4 0 1.4 100.0 G 0.021 0.004 TRIMBLE NETR5 TRIMBLE NETRS #AR_L12SLS43030 SUTH SUTV 0.000 88 0.4 0 0.4 100.0 G 0.012 0.002 ASHTECH UZ-12 JPS EGGDT #AR_L12sLuL3030 TAH1 TAH2 0.000 92 0.3 0 0.3 100.0 G 0.003 0.001 ASHTECH Z-XII3 ASHTECH Z-XII3 #AR_L12TDCB3030 TID1 TIDB 0.000 88 1.0 0 1.1 100.0 G 0.032 0.008 TRIMBLE NETR8 ASHTECH UZ-12 #AR_L12uLTI3030 TAH2 THTI 0.028 82 1.2 0 1.3 100.0 G 0.033 0.010 ASHTECH Z-XII3 TRIMBLE NETR8 #AR_L12WR0M3030 WTZR WTZZ 0.002 98 1.5 4 1.6 95.9 G 0.029 0.009 LEICA GRX1200+GNSS JAVAD TRE_G3TH DELTA #AR_L12WR0M3030 WTZR WTZZ 0.002 116 1.5 0 1.6 100.0 R 0.098 0.022 LEICA GRX1200+GNSS JAVAD TRE_G3TH DELTA #AR_L12WR0M3030 WTZR WTZZ 0.002 214 1.5 4 1.6 98.1 GR 0.098 0.017 LEICA GRX1200+GNSS JAVAD TRE_G3TH DELTA #AR_L12XGTX3030 TIXG TIXI 0.000 144 0.5 0 0.5 100.0 G 0.019 0.003 TPS ODYSSEY_E JPS EGGDT #AR_L12XGTX3030 TIXG TIXI 0.000 120 0.5 0 0.5 100.0 R 0.019 0.003 TPS ODYSSEY_E JPS EGGDT #AR_L12XGTX3030 TIXG TIXI 0.000 264 0.5 0 0.5 100.0 GR 0.019 0.003 TPS ODYSSEY_E JPS EGGDT #AR_L12Y30N3030 YAR3 YARR 0.020 94 0.9 4 0.9 95.7 G 0.034 0.007 LEICA GRX1200GGPRO LEICA GRX1200PRO #AR_L12YAY33030 YAR2 YAR3 0.018 90 0.9 4 0.9 95.6 G 0.039 0.006 ASHTECH UZ-12 LEICA GRX1200GGPRO #AR_L12---------------------------------------------------------------------------------------------------------------------Tot: 30 1.211 3388 4.0 58 4.5 98.3 G 0.347 0.033 #AR_L12Tot: 9 0.275 992 1.1 0 1.8 100.0 R 0.193 0.017 #AR_L12Tot: 30 1.211 4380 4.0 58 4.5 98.7 GR 0.347 0.030 #AR_L12

LS combination of CODE’s accumulated IGSFINAL and EPNFINAL SDByyssss.LST results (WL)

ASHTECH Z18 : 22.120 2.268 JAVAD TRE_G3TH DELTA: 218.901 0.675 JPS EGGDT : 58.271 0.606 JPS E_GGD : 128.505 0.565 JPS LEGACY : 111.921 0.609 LEICA GRX1200+GNSS : -269.900 0.753 LEICA GRX1200GGPRO : -242.546 0.484 NOV OEMV3 : -247.286 0.516 SEPT POLARX3ETR : -501.984 0.533 TPS EGGDT : 70.275 0.726 TPS EUROCARD : 155.776 0.652 TPS E_GGD : 121.529 0.868 TPS LEGACY : 92.682 0.517 TPS NETG3 : 52.682 0.507 TPS ODYSSEY_E : 57.586 0.611 TRIMBLE NETR5 : 96.551 0.515 TRIMBLE NETR8 : 74.919 0.908

Receiver type SD bias RMS error (ns)

GNSS (mixed)

GNSS (unmixed)

Implemented “GPS/GLONASS-Capable”LAMBDA Ambiguity Resolution Scheme(s)

List of GNSS biases

Intersystem phase biases (1/4)

• Number of double-difference observations (per epoch) for four different analysis (or combination) scenarios, assuming 4 GPS and 2 GLONASS satellites in view.

• GPS-GLONASS inter-system phase bias variability, specifically the ionosphere-free linear combination of L1 and L2 biases, for baseline ZIMJ-ZIMT, for days 309–315, 2006 (GPS week 1400).

• GPS-GLONASS inter-system phase bias variability, the ionosphere-free linear combination (LC) of L1 and L2 biases, compared to biases directly associated with L1 and L2, for baseline ZIMJ-ZIMT, for day 309, 2006.

• Variability of epoch parameters compensating a supposed “GPS-GPS” differential phase bias between two sets of PRNs (PRN 01–16 and PRN 17–32), the ionosphere-free linear combination (LC) of L1 and L2 biases, compared to biases directly associated with L1 and L2, for baseline ZIMJ-ZIMT, for day 309, 2006.

List of GNSS biases

GLONASS-GPS intersystem translation parameters with respect to station coordinates

GLONASS

Mixed RP

GLONASS-GPS intersystem translation parameters with respect to troposphere ZPD

Troposhere ZPD

GLONASS

Troposhere ZPD

GLONASS

GNSS analysis updates and treatment of these intersystem translation parameters at CODE

• Since GPS week 1619 (EUREF: 1615), an extra set of (3+1) parameters is set up for each GLONASS observing station to characterize- a GLONASS-GPS receiver antenna offset vector and- a GLONASS-GPS ZPD troposphere bias.

• Starting with GPS week 1625, these GLONASS-GPS bias parameters (4 for each GNSS station) are determined on a weekly basis and subsequently used for generation of our daily IGS analysis results.

• Note 1: The datum definition used for the GLONASS-GPS receiver antenna offset vectors is similar to that used for station coordinates: no-net translation and no-net rotation conditions with respect to all GLONASS observing stations are imposed.

• Note 2: GLONASS-GPS ZPD troposphere biases are generally treated unconstrained.

• Note 3: Our weekly SINEX contribution implicitly includes these GLONASS-GPS bias parameters (4 for each GNSS station).

Mean GLONASS-GPS troposphere ZPD biases: CODE IGS (global) weekly results

GLONASS-GPS troposphere ZPD biases (for up to 143 IGS GNSS stations)

1615 1620 1625 1630 1635 1640

Time (GPS week)

MeanMedian

Model switch from IGS05 to IGS08

GLONASS-GPS translation parameter results concerning N/E and U/ZPD: IGS week 1632

North versus East (IGS week 1632)

-10 -5 0 5 10 15

East (mm)

Up versus ZPD (IGS week 1632)

-8 -6 -4 -2 0 2 4 6

ZPD (mm)U

GLONASS-GPS translation parameter results (reprocessed) (1/2)

Comparison of mean GLONASS-GPS biases (2003-2010)as computed for station height and troposphere IGS05:

IGS08:

GLONASS-GPS translation parameter results (reprocessed) (2/2)

Comparison of mean GLONASS-GPS biases (2003-2010)as computed for station height and troposphere IGS05:

IGS08:

GLONASS

More and more GNSS …

GLONASS

Third GNSSNorth

GLONASS

Third GNSS

Fourth GNSS

List of GNSS biases

Remark concerning GNSS antenna phase center modeling• GNSS satellite antenna phase center offsets and variations

are commonly referred to the ionosphere-free LC• A set of corresponding parameters is set up in CODE’s

ionosphere analysis (with respect to the geometry-free LC)- retrieval of GNSS antenna information for L1 and L2

List of GNSS biases

GPS quarter-cycle issue (again crucial)

• L2(C) may show quarter-cycle biases for GPS Block IIR-M/IIF (with respect to previous, “non-C2” GPS generations) particularly in case of:- Leica- NovAtel- Javad

[IGSMAIL-6583] GPS quarter-cycle biasesUntil recently, we did expect GPS quarter-cycle biases between L2(P)and L2(C) only for Leica and NovAtel receivers. As a consequence,ambiguity resolution was not permitted between modernized GPSsatellites (specifically Block IIR-M and IIF) and older generations assoon as a receiver type belonging to the mentioned receiver group getsinvolved.

We could recognize, however, three additional characteristics that mustbe taken into account:

1. Javad receivers obviously also belong to this receiver group(potentially revealing quarter-cycle biases). We could verifycorresponding biases for the JAVAD TRE_G3TH DELTA receivers operated atAREV, DGAV, TABV, WTZZ. It is worth mentioning that AREV, DGAV, TABVstarted to provide C2 and thus implicitly L2(C) on February 3, 2012.Quarter-cycle biases started to occur exactly in coincidence with thatdate (day 034 of 2012) for these Javad receivers. Verification waspossible on the zero baselines AREV-AREQ (wrt ASHTECH UZ-12), DGAV-DGAR(wrt ASHTECH UZ-12), and ultimately on the 50km baseline TABV-JPLV (wrtJPS EGGDT).

2. Moreover, we realized that there are certain time periods forparticular modernized GPS satellites where C2 and L2(C) seem to becommonly unavailable (no receiver model was able to provide C2 andL2(C) at all). SVN49 is a prominent candidate in the table of such timeperiods:

PRN01/SVN49: 54951 <= MJD < 54970PRN25/SVN62: 55353 <= MJD < 55375PRN01/SVN49: 55677 <= MJD < 55688PRN24/SVN49: 55959 <= MJD < 56001

3. Finally, we noticed cases, where L2(C) was not observed byparticular receivers for one (or a subset) of the modernized GPSsatellites.

As a consequence of the above observations, we changed our analysissoftware in a way that ambiguity resolution is generally not permittedbetween modernized GPS satellites as soon as a Javad, Leica, or aNovAtel receiver type gets involved.

Our basic principle

• Multi-GNSS analysis with best possible consistency (among all considered GNSS) is strived for:- all significant biases must be taken into account (either

modeled/corrected or estimated)- finding the optimum/tradeoff between over and under

estimation of an analysis problem

We may summarize that …

• GNSS biases become relevant when- different observable types,- different frequencies,- different GNSS (or satellite generations),- different receiver antenna types,- different receiver antenna mountings,- different receiver antenna environments,- different receiver types,- different receiver firmware versions,- or, ultimately, different observation techniques (…)are involved.

Thank you for your attention …

Plethora of GNSS observables: different GPS/GLONASS receiver tracking (1/3)

AOA BENCHMARK ACT ( 10) . G:P1 G:P2 . . . . .AOA BENCHMARK ACT ( 88) G:C1 G:P1 G:P2 . . . . .AOA SNR-12 ACT ( 22) G:C1 G:P1 G:P2 . . . . . AOA SNR-8000 ACT ( 31) G:C1 G:P1 G:P2 . . . . . ASHTECH PF500 ( 11) G:C1 . G:P2 . R:C1 . R:P2 .ASHTECH UZ-12 ( 513) G:C1 G:P1 G:P2 . . . . . ASHTECH Z-XII3 ( 8) G:C1 . G:P2 . . . . . ASHTECH Z-XII3 ( 229) G:C1 G:P1 G:P2 . . . . . ASHTECH Z-XII3T ( 129) G:C1 G:P1 G:P2 . . . . . ASHTECH Z18 ( 24) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 .BLACKJACK ( 4) G:C1 G:P1 G:P2 . . . . .DICOM GTR50 ( 11) G:C1 G:P1 G:P2 . . . . .IFEN SX_NSR_RT_400 ( 11) G:C1 . G:P2 . . . . .JAVAD TRE_G3T DELTA ( 11) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 .JAVAD TRE_G3TH DELTA ( 1) G:C1 . G:P2 . . . . .JAVAD TRE_G3TH DELTA ( 131) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 .JPS EGGDT ( 141) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 .JPS EUROCARD ( 10) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 .JPS E_GGD ( 55) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 .JPS LEGACY ( 4) G:C1 G:P1 G:P2 . . . . .JPS LEGACY ( 192) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 .LEICA GRX1200+GNSS ( 172) G:C1 . G:P2 . R:C1 . R:P2 .LEICA GRX1200GGPRO ( 1) G:C1 . G:P2 . . . . .LEICA GRX1200GGPRO ( 452) G:C1 . G:P2 . R:C1 . R:P2 .LEICA GRX1200PRO ( 44) G:C1 . G:P2 . . . . .NOV OEM4-G2 ( 11) G:C1 . G:P2 . . . . . NOV OEMV3 ( 44) G:C1 . G:P2 . R:C1 . R:P2 .ROGUE SNR-8000 ( 23) G:C1 . G:P2 . . . . . ROGUE SNR-8100 ( 11) G:C1 . G:P2 . . . . .

SEPT POLARX2 ( 71) G:C1 G:P1 G:P2 . . . . .SEPT POLARX3ETR ( 11) G:C1 G:P1 G:P2 . R:C1 . . R:C2SEPT POLARX3ETR ( 11) G:C1 G:P1 G:P2 . R:C1 . R:P2 .SEPT POLARX4TR ( 5) G:C1 G:P1 G:P2 . R:C1 . . R:C2SEPT POLARX4TR ( 4) G:C1 G:P1 G:P2 . R:C1 . R:P2 .TPS EGGDT ( 11) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 .TPS EUROCARD ( 9) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 .TPS E_GGD ( 79) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 .TPS GB-1000 ( 33) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 . TPS LEGACY ( 13) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 .TPS NET-G3A ( 17) G:C1 G:P1 G:P2 . . . . . TPS NET-G3A ( 88) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 . TPS NETG3 ( 11) G:C1 G:P1 G:P2 . . . . .TPS NETG3 ( 121) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 .TPS ODYSSEY_E ( 44) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 .TRIMBLE 4000SSE ( 11) G:C1 . G:P2 . . . . .TRIMBLE 4000SSI ( 65) G:C1 . G:P2 . . . . .TRIMBLE 4700 ( 33) G:C1 . G:P2 . . . . .TRIMBLE 5700 ( 21) G:C1 . G:P2 . . . . .TRIMBLE NETR5 ( 13) G:C1 . G:P2 . . . . .TRIMBLE NETR5 ( 96) G:C1 . G:P2 . R:C1 . R:P2 .TRIMBLE NETR5 ( 120) G:C1 . G:P2 . R:C1 R:P1 R:P2 .TRIMBLE NETR8 ( 29) G:C1 . G:P2 . . . . .TRIMBLE NETR8 ( 32) G:C1 . G:P2 . R:C1 R:P1 . .TRIMBLE NETR8 ( 62) G:C1 . G:P2 . R:C1 R:P1 R:P2 .TRIMBLE NETR8 ( 18) G:C1 G:P1 G:P2 . R:C1 R:P1 R:P2 .TRIMBLE NETR9 ( 18) G:C1 . G:P2 . . . . .TRIMBLE NETR9 ( 53) G:C1 . G:P2 . R:C1 . R:P2 .TRIMBLE NETR9 ( 110) G:C1 . G:P2 . R:C1 R:P1 R:P2 .TRIMBLE NETRS ( 244) G:C1 . G:P2 . . . . .TRIMBLE NETRS ( 9) G:C1 G:P1 G:P2 . . . . .

AOA BENCHMARK ACT (2)ASHTECH Z-XII3 (2)JAVAD TRE_G3TH DELTA (2)JPS LEGACY (2)LEICA GRX1200GGPRO (2)SEPT POLARX3ETR (2)SEPT POLARX4TR (2)TPS NET-G3A (2)TPS NETG3 (2)TRIMBLE NETR5 (3)TRIMBLE NETR8 (4)TRIMBLE NETR9 (3)TRIMBLE NETRS (2)

AREV0610.12O: JAVAD TRE_G3TH DELTA G:L1 G:L2 G:C1 G:P1 G:P2 G:C2 G:L5 G:C5 R:L1 R:L2 R:C1 R:P1 R:P2 R:C2 DGAV0610.12O: JAVAD TRE_G3TH DELTA G:L1 G:L2 G:C1 G:P1 G:P2 G:C2 G:L5 G:C5 R:L1 R:L2 R:C1 R:P1 R:P2 R:C2 OBE30610.12O: JAVAD TRE_G3TH DELTA G:L1 G:L2 G:C1 G:P1 G:P2 . G:L5 G:C5 R:L1 R:L2 R:C1 R:P1 R:P2 . OUS20610.12O: JAVAD TRE_G3TH DELTA G:L1 G:L2 G:C1 G:P1 G:P2 . G:L5 G:C5 R:L1 R:L2 R:C1 R:P1 R:P2 . POTS0610.12O: JAVAD TRE_G3TH DELTA G:L1 G:L2 G:C1 G:P1 G:P2 . G:L5 G:C5 R:L1 R:L2 R:C1 R:P1 R:P2 . TABV0610.12O: JAVAD TRE_G3TH DELTA G:L1 G:L2 G:C1 G:P1 G:P2 G:C2 G:L5 G:C5 R:L1 R:L2 R:C1 R:P1 R:P2 R:C2 TASH0610.12O: JAVAD TRE_G3TH DELTA G:L1 G:L2 G:C1 G:P1 G:P2 . G:L5 G:C5 R:L1 R:L2 R:C1 R:P1 R:P2 . ULAB0610.12O: JAVAD TRE_G3TH DELTA G:L1 G:L2 G:C1 G:P1 G:P2 . G:L5 G:C5 R:L1 R:L2 R:C1 R:P1 R:P2 . WTZZ0610.12O: JAVAD TRE_G3TH DELTA G:L1 G:L2 G:C1 G:P1 G:P2 G:C2 . . R:L1 R:L2 R:C1 R:P1 R:P2 R:C2 CONZ0610.12O: LEICA GRX1200+GNSS G:L1 G:L2 G:C1 . G:P2 G:C2 G:L5 G:C5 R:L1 R:L2 R:C1 . R:P2 . WTZR0610.12O: LEICA GRX1200+GNSS G:L1 G:L2 G:C1 . G:P2 G:C2 G:L5 G:C5 R:L1 R:L2 R:C1 . R:P2 . NIST0610.12O: NOV OEM4-G2 G:L1 G:L2 G:C1 . G:P2 . . . . . . . . . UNBN0610.12O: NOV OEMV3 G:L1 G:L2 G:C1 . G:P2 G:C2 . . R:L1 R:L2 R:C1 . R:P2 . CONT0610.12O: SEPT POLARX2 G:L1 G:L2 G:C1 G:P1 G:P2 . . . . . . . . . MIZU0610.12O: SEPT POLARX2 G:L1 G:L2 G:C1 G:P1 G:P2 . . . . . . . . . WAB10610.12O: SEPT POLARX2 G:L1 G:L2 G:C1 G:P1 G:P2 . . . . . . . . . ZWE20610.12O: SEPT POLARX2 G:L1 G:L2 G:C1 G:P1 G:P2 . . . . . . . . . UNBT0610.12O: TPS NET-G3 G:L1 G:L2 G:C1 G:P1 G:P2 G:C2 . . R:L1 R:L2 R:C1 R:P1 R:P2 R:C2 ABMF0610.12O: TRIMBLE NETR9 G:L1 G:L2 G:C1 . G:P2 . G:L5 G:C5 R:L1 R:L2 R:C1 . R:P2 . BRST0610.12O: TRIMBLE NETR9 G:L1 G:L2 G:C1 . G:P2 . G:L5 G:C5 R:L1 R:L2 R:C1 . R:P2 . GMSD0610.12O: TRIMBLE NETR9 G:L1 G:L2 G:C1 . G:P2 G:C2 G:L5 G:C5 R:L1 R:L2 R:C1 R:P1 R:P2 R:C2 GRAC0610.12O: TRIMBLE NETR9 G:L1 G:L2 G:C1 . G:P2 . G:L5 G:C5 R:L1 R:L2 R:C1 . R:P2 . GRAS0610.12O: TRIMBLE NETR5 G:L1 G:L2 G:C1 . G:P2 . G:L5 G:C5 R:L1 R:L2 R:C1 R:P1 R:P2 . KERG0610.12O: TRIMBLE NETR9 G:L1 G:L2 G:C1 . G:P2 . G:L5 G:C5 R:L1 R:L2 R:C1 R:P1 R:P2 . LMMF0610.12O: TRIMBLE NETR9 G:L1 G:L2 G:C1 . G:P2 . G:L5 G:C5 R:L1 R:L2 R:C1 . R:P2 . REUN0610.12O: TRIMBLE NETR9 G:L1 G:L2 G:C1 . G:P2 . G:L5 G:C5 R:L1 R:L2 R:C1 . R:P2 . TLSE0610.12O: TRIMBLE NETR9 G:L1 G:L2 G:C1 . G:P2 . G:L5 G:C5 R:L1 R:L2 R:C1 R:P1 R:P2 . UNB30610.12O: TRIMBLE NETR5 G:L1 G:L2 G:C1 . G:P2 G:C2 G:L5 G:C5 R:L1 R:L2 R:C1 . R:P2 R:C2

Plethora of GNSS observables: different Giove/Galileo/SBAS receiver tracking (2/2)

AREV0610.12O: JAVAD TRE_G3TH DELTA E:L1 E:C1 E:L5 E:C5 . . . . . . . . E01 E02DGAV0610.12O: JAVAD TRE_G3TH DELTA E:L1 E:C1 E:L5 E:C5 . . . . . . . . E01 E02OBE30610.12O: JAVAD TRE_G3TH DELTA E:L1 E:C1 E:L5 E:C5 . . . . . . . . E01 E02OUS20610.12O: JAVAD TRE_G3TH DELTA E:L1 E:C1 E:L5 E:C5 . . . . . . . . E01 E02 E11POTS0610.12O: JAVAD TRE_G3TH DELTA E:L1 E:C1 E:L5 E:C5 . . . . . . . . E01 E02 E11 E12TABV0610.12O: JAVAD TRE_G3TH DELTA E:L1 E:C1 E:L5 E:C5 . . . . . . . . E01 E02TASH0610.12O: JAVAD TRE_G3TH DELTA E:L1 E:C1 E:L5 E:C5 . . . . . . . . E01 E02ULAB0610.12O: JAVAD TRE_G3TH DELTA E:L1 E:C1 E:L5 E:C5 . . . . . . . . E01 E02 E11 E12WTZZ0610.12O: JAVAD TRE_G3TH DELTA . . . . . . . . S:L1 S:C1 . . s20 s24 s26CONZ0610.12O: LEICA GRX1200+GNSS . . . . . . . . S:L1 S:C1 . . s20 s33 s35 s38WTZR0610.12O: LEICA GRX1200+GNSS . . . . . . . . S:L1 S:C1 . . s20 s24 s26NIST0610.12O: NOV OEM4-G2 . . . . . . . . S:L1 S:C1 . . s33 s38UNBN0610.12O: NOV OEMV3 . . . . . . . . S:L1 S:C1 . . s35 s38CONT0610.12O: SEPT POLARX2 . . . . . . . . S:L1 S:C1 . . s33 s35 s38MIZU0610.12O: SEPT POLARX2 . . . . . . . . S:L1 S:C1 . . s29 s37WAB10610.12O: SEPT POLARX2 . . . . . . . . S:L1 S:C1 . . s20 s24 s26ZWE20610.12O: SEPT POLARX2 . . . . . . . . S:L1 S:C1 . . s20 s24 s26UNBT0610.12O: TPS NET-G3 . . . . . . . . S:L1 S:C1 . . s35 s38ABMF0610.12O: TRIMBLE NETR9 E:L1 E:C1 E:L5 E:C5 E:L7 E:C7 E:L8 E:C8 S:L1 S:C1 S:L5 S:C5 E12 E51 E52 s20 S33 S35 S38BRST0610.12O: TRIMBLE NETR9 E:L1 E:C1 E:L5 E:C5 E:L7 E:C7 E:L8 E:C8 S:L1 S:C1 . . E11 E12 E51 E52 s20 s24 s26GMSD0610.12O: TRIMBLE NETR9 E:L1 E:C1 E:L5 E:C5 E:L7 E:C7 E:L8 E:C8 . . . . E11 E12 E51 E52GRAC0610.12O: TRIMBLE NETR9 E:L1 E:C1 E:L5 E:C5 E:L7 E:C7 E:L8 E:C8 S:L1 S:C1 . . E11 E12 E51 E52 s20 s26GRAS0610.12O: TRIMBLE NETR5 . . . . . . . . S:L1 S:C1 . . s20 s26KERG0610.12O: TRIMBLE NETR9 E:L1 E:C1 E:L5 E:C5 E:L7 E:C7 E:L8 E:C8 . . . . E11 E12 E51 E52LMMF0610.12O: TRIMBLE NETR9 E:L1 E:C1 E:L5 E:C5 E:L7 E:C7 E:L8 E:C8 S:L1 S:C1 S:L5 S:C5 E11 E12 E51 E52 s20 S33 S35 S38REUN0610.12O: TRIMBLE NETR9 E:L1 E:C1 E:L5 E:C5 E:L7 E:C7 E:L8 E:C8 S:L1 S:C1 . . E11 E12 E51 E52 s20 s24 s26TLSE0610.12O: TRIMBLE NETR9 E:L1 E:C1 E:L5 E:C5 E:L7 E:C7 E:L8 E:C8 S:L1 S:C1 . . E11 E12 E51 E52 s20 s24 s26UNB30610.12O: TRIMBLE NETR5 . . . . . . . . S:L1 S:C1 S:L5 S:C5 s33 s35 S38

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