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BILL HENNING,Prof LS.

BILL HENNING,Prof LS.

• GNSS MONUMENTS IN SPACE

• OPUS BASICS- ANTENNAS, RINEX FILES

• OPUS STATIC, RAPID STATIC AND SHARED

• EXAMINING OPUS RESULTS

• OPUS PROJECTS

• HYBRID TO GRAVIMETRIC GEOID MODELS

• CAVEATS FOR USING OPUS, IMPROVING THE RESULTS

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“GNSS”

GLONASS

GPS

GALILEO

COMPASS (BEIDOU-2)

RUSSIAN AEROSPACEDEFENSE FORCES

DEPT. OFDEFENSE

EU & ESA

WALMARTCHINESE NATIONALSPACE ADMINISTRATION

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GNSS CORS USER

• 200 DATA PROVIDERS• APPROX. 2000 STATIONS• DAILY PROCESSING• MAINTAINED IN IGS 08 (2005)• TRANSFORMED TO NAD 83• DAILY AND LONG TERM DATA SERIES• “LOOSER” POSITIONS THAN A LOCAL RTN• BACKBONE CORS TO BE OWNED & OPERATED BY NGS

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ONLINE POSITIONING USER SERVICE

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• ALL CURRENTLY DO NOT HANDLE GLONASS

• NO KINEMATIC (CAN BE DELETED FROM A RINEX FILE)

• DUAL FREQUENCY DATA (L1 & L2)

• ACCURATE HEIGHTS REQUIRE THE CORRECT ANTENNA HEIGHT ANDTYPE

OPUS – STATIC (OPUS-S)OPUS-RAPID STATIC (OPUS-RS)

OPUS-PROJECTS (OPUS-P)OPUS-SHARED (OPUS-DB)

http://www.ngs.noaa.gov/ANTCAL/

CURRENTLYAVAILABLE:

THE OPUS PAGE AT NGS

http://www.ngs.noaa.gov/OPUS/

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WHY DO I NEED THE ANTENNA TYPE?

The Antenna Reference Point (ARP) is almostalways located in the center of the bottom

surface of the antenna.

The antenna offsets are the distancebetween the phase centers and the

ARP

You do not need to know theseoffsets. They are passed to the

processing software through theantenna type

INCORRECT OR MISSINGANTENNA TYPE → BIG

VERTICAL ERRORS

ARP

phase ctr.

The antenna phase centers arelocated somewhere around here.

Antenna

Type A

Antenna

Type B

Different

Phase Patterns

ANTENNA PHASE CENTER VARIATION

Elevation Angle (deg.)

SV elevation and varyingphase patterns affect signalinterpretation differently

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RELATIVE vs. ABSOLUTEANTENNA CALIBRATION

ABSOLUTEANTENNA CALIBRATION

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ABSOLUTEANTENNA

CALIBRATION

USING ABSOLUTE ANTENNA MODELS• IGS 2008 (2005) AND/OR NAD 83 (2011) EPOCH 2010.00 DATA FROM CORS USE THE

ABSOLUTE ANTENNA MODELS. ALL ANTENNA OFFSETS AND PHASE CENTER VARIATIONS AREINDEPENDENT OF THE REFERENCE ANTENNA

• THE OLDER NAD 83 ( CORS 96 EPOCH 2002, NAD 83 (2007) EPOCH 2002 OR ITRF 2000 EPOCH1997 DATA FROM CORS USE THE RELATIVE ANTENNA MODELS. ALL ANTENNA OFFSETS (PCO)AND PHASE CENTER VARIATIONS (PCV) ARE COMPUTED WITH RESPECT TO A REFERENCEANTENNA WHICH IS NORMALLY ASSIGNED ZERO PCV VALUES

• RTN PROCESS ANTENNA PHASE CENTER (APC) TO APC (IN A VRS). ROVER IN MASTER-AUXILIARY USES ITS OWN MODEL TO PRODUCE ITS APC AND PRODUCE A BASELINE FROMTHE RTN APC .

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USE THE CORRECT ANTENNA MODEL

DATA SHEET NO ANTENNA

CORRECT ANTENNAWRONG ANTENNA

HOW DOES OPUS WORK?• 15 MINUTES TO 48 HOURS OF GPS L1 + L2 DATA CROSSING MIDNIGHT ONCE).

• POSITION WITH RESPECT TO 3 SUITABLE CORS FOR OPUS-S(OR IGS SITES IF: 1) NO NAD 83 POSITIONS ARE AVAILABLE AND 2) THE HOSTCOUNTRY HAS AN AGREEMENT WITH NGS. IN THESE INTERNATIONAL CASES, ITRFCOORDINATES ONLY ARE RETURNED, AND THERE ARE NO STATE PLANE OR US GRIDCOORDINATES )

• POSITION WITH RESPECT TO 3 UP TO 9 SUITABLE CORS FOR OPUS-RS

• SOLUTION VIA EMAIL (USUALLY IN MINUTES)

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ALLOWABLE DATA FORMATS

- COMPRESSED ARCHIVE OF MULTIPLE FILES. FORMAT MUST BE RINEX (“SITE123H.04O”) ORHATANAKA (“SITE123H.04D”)

- COMPRESSED INDIVIDUAL FILES “SITE123H.ZIP”MUST CONTAIN FORMAT “SITE123H.06O” OR “SITE123H.06D”

- MANUFACTURER’S NATIVE / RAW (BINARY)—UNCOMPRESSED--AS LONG ASUNAVCO’S TEQC PROGRAM CAN PROCESS IT

-RINEX 2.x RECEIVER INDEPENDENT EXCHANGE--UNCOMPRESSED

- RECORDING (EPOCH) RATES OF 1, 2, 3, 5, 10,15, OR 30 SECONDS; THOUGH ALL AREDECIMATED TO 30 SECONDS.

RECEIVER INDEPENDENTEXCHANGE FILES

(G, R, E, S)

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RINEX DATA

C:\Users\BillGail\

Desktop\MIDTOWNSHIPCORSC:\Users\BillGail\

Desktop\MIDTOWNSHIPCORS

NJCM – MIDTOWNSHIP CORS:SPC NJN: 29718.584

E: 123801.055

Adobe Acrobat

Document

Adobe Acrobat

Document

Adobe Acrobat

Document

4 HOURS 1 HOUR

DATA SHEET

GPS NAVIGATION MESSAGE IN RINEX FORMAT

EACH 30 SECOND FRAME BEGINS PRECISELY ON THE MINUTE OR HALF MINUTE AS INDICATED BY THEATOMIC CLOCK ON EACH SATELLITE.THE FIRST PART ENCODES THE WEEK NUMBER AND THE TIME WITHIN THE WEEK, AS WELL AS THE HEALTHOF THE SATELLITE. THE SECOND PART OF THE MESSAGE, THE EPHEMERIS. THE LAST PART OF THEMESSAGE, THE ALMANAC, CONTAINS COARSE ORBIT AND STATUS INFORMATION FOR ALL SATELLITES INTHE NETWORK AS WELL AS DATA RELATED TO ERROR CORRECTION.

SIGNALS ARE ENCODED USING CODE DIVISION MULTIPLE ACCESS (CDMA) ALLOWING MESSAGES FROMINDIVIDUAL SATELLITES TO BE DISTINGUISHED FROM EACH OTHER BASED ON UNIQUE ENCODINGS FOREACH SATELLITE (THAT THE RECEIVER MUST BE AWARE OF). TWO DISTINCT TYPES OF CDMA ENCODINGSARE USED: THE COARSE/ACQUISITION (C/A OR CIVIL) CODE, AND THE PRECISE (P) CODE, THAT ISENCRYPTED SO THAT ONLY THE U.S. MILITARY CAN ACCESS IT.THE EPHEMERIS IS UPDATED EVERY 2 HOURS AND IS GENERALLY VALID FOR 4 HOURS. THE ALMANAC ISUPDATED TYPICALLY EVERY 24 HOURS.

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GPS NAVIGATION MESSAGE

C:\Presentations\

NJSPLS2018\data\JD273\a2

JPEG image

GPS ORBIT FILES – SP3

C:\Presentations\

NJSPLS2018\igs18844.sp3

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TRANSLATION: BINARY DATA READING/TRANSLATION OF NATIVE BINARY FORMATS(OPTIONAL RINEX FILE CREATION FOR OBS, NAV, AND/OR MET FILES OR OPTIONALCREATION OF BINEX)EDITING: INCLUDING TIME WINDOWING; FILE SPLICING; SV OR OTHER FILTERING;METADATA EXTRACTION, EDITING, AND/OR CORRECTION OF RINEX HEADERMETADATA OR BINEX METADATA RECORDSQUALITY CHECK: QUALITY CHECKING OF GPS AND/OR GLONASS DATA (NATIVE BINARY,BINEX, OR RINEX OBSERVATION FILES; WITH OR WITHOUT EPHEMERIDES)

https://www.unavco.org/software/data-processing/teqc/teqc.html

TEQC COMMAND LINE

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http://teqc.silkwerks.com/

USING OPUS

• VERIFY STATION AVAILABILITY ON THE DAY OF THE DATA CAPTURE (FOR AWELL KNOWN & USED STATION)

• CHECK SHORT TERM AND LONG TERM CORS ANTENNA POSITIONS

IF NECESSARY, SELECT STATIONS WITH THE HIGHEST INTEGRITY ANDLEAST DEVIATION FROM THE PUBLISHED COORDINATES WHEN USINGOPUS-S.

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CORS SHORT TERMPLOTS

CHANGES IN “h” CAN BE NEITHER LINEAR NOR CYCLICAL

CORS LONG TERMPLOTS

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2.6 CM

1.8 CM

OPUS-S: 4 HOUR OBSERVATION SWEET SPOT

1.5 CM

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OPUS ORTHO HEIGHT ACCURACY

OPUS USES THE ELLIPSOID HEIGHT FROM YOUR OBSERVATION DATA AND THECURRENT HYBRID GEOID MODEL TO PRODUCE A NAVD 88 ORTHOMETRICHEIGHT. THEREFORE, SINCE ELLIPSOID HEIGHTS, LEVELING DATA AND THEHYBRID GEOID MODEL ALL CONTAIN SOME UNCORRELATED ERROR, ALWAYSEXPECT SOME DIFFERENCE FROM OPUS TO LOCAL “TRUTH” ON PASSIVEMARKS.EVERY OPUS POSITION IS AUTONOMOUS (EXCEPT OPUS-PROJECTS) ANDUNRELATED TO OTHER POINTS.

OPUS – S (AND -P)

• DUAL FREQUENCY DATA

• ≥ 2, ≤48 HOURS DATA

• PAGES ENGINE

• OBS USED > 90%

• # FIXED AMB > 50%

• OVERALL RMS < 3 cm

• PEAK TO PEAK < 5 cm

OPUS - RS

• DUAL FREQUENCY DATA

• ≥ 15 MINUTES, ≤2 HOURS DATA

• RSGPS ENGINE

• ≥ 3, ≤ 9 CORS, 250 KM

• OBS USED > 50%

• QUALITY INDICATOR ≥ 3

• NORMALIZED RESIDUAL ≈ 1

• ≥ 4, ≤48 HOURS DATA

• OBS USED ≥ 70%

• # FIXED AMB ≥ 70%

• OVERALL RMS ≤ 3 cm

• PEAK TO PEAK ≤ 4 cm, 8 cm ellipsoid

• DESCRIPTION, PICTURES

OPUS - SHARED

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PAGES PROCESSING ENGINE(PROGRAM FOR THE ADJUSTMENT OF

GPS EPHEMERIDES)

OPUS-S CONCEPTIf you can afford to occupy a mark for alonger time, the change in satelliteposition relative to your antennaeliminates all but the appropriate set ofcorrections. This is the strategy of OPUSStatic: given 2 hrs of data or more, theatmosphere corrections, the integers andthe antenna coordinates can beconfidently determined in theprocessing.

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HOW DOES OPUS COMPUTE YOUR POSITION?

3 SINGLE BASELINES COMPUTED

3 POSITIONS AVERAGED —SIMPLE MEAN (EQUAL WEIGHTS)DIFFERENCES BETWEEN POSITIONS INCLUDE ANY ERRORS IN CORS

COORDINATES

HOW DOES OPUS-S PICK BASE STATIONS?1. ESTIMATE POSITION FOR REMOTE STATION

2. COMPUTE DISTANCE TO EVERY AVAILABLE CORS

3. SORT CORS BY INCREASING DISTANCE

4. SELECT THE 5 CLOSEST CORS

5. LOOK AT 1ST 3 CORS WITH TEQC PROGRAM. CRITERIA:

● DATA COVER TIME SPAN FOR REMOTE STATION

● > 80% OF DATA AVAILABLE

● LOW MULTIPATH

● IF NOT, REPLACE WITH 4TH CORS (THEN 5TH)

6. START SINGLE BASELINE SOLUTIONS USING 1ST 3 CORS

● CHECK SOLUTION QUALITY

● IF BAD SOLUTION, REPLACE CORS WITH 4TH (THEN 5TH)

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• OPUS WILL USE THE BEST AVAILABLE EPHEMERIS:

“IGS” FINAL POST-FIT ORBIT--BETTER THAN 1 CM

(10-14 DAYS WAIT)

“IGR” RAPID POST-FIT ORBIT--BETTER THAN 2 CM

(13-17 HOURS WAIT)

“IGU” ULTRA-RAPID PREDICTED ORBIT--BETTER THAN 20 CM

(AVAILABLE IMMEDIATELY, 6 HOUR UPDATES)

(BROADCAST ORBITS, 1-3 METERS ACCURACY, ARE USED BY REAL-TIMEAPPLICATIONS)

• NAVIGATION FILE USED

WHAT EPHEMERIS WILL OPUS USE?

http://www.ngs.noaa.gov/orbits/orbit_data.shtml

The SP3-c format was developed to allow one to putGPS, GLONASS, and Galileo satellites all in the samefile, and also to give standard deviations for thesatellite XYZ coordinates and clock offset at eachepoch

USED IN RTX/PPP

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HOW DOES OPUS-S COMPUTE ERRORS?

EW

S

N1 Σ STANDARDDEVIATION

PEAK-TO-PEAK ERROR

MORE CONSERVATIVE~ 2 Σ

PEAK-TO-PEAK DISTANCES

-USING IGS VELOCITIES, TRANSFORM STATION COORDINATES TAKEN FROM NGSIDB TO

IGS VALUES AT THE MIDPOINT OF THE OBSERVATION SESSION USING HTDP.-COMPUTE 3 VECTORS AND STANDARD DEVIATIONS , TO REMOTE POINT IN IGS

-TRANSFORM IGS VECTORS TO NAD 83 (2011)-RECOMPUTE NAD 83 (2011) INDEPENDENT POSITIONS AND AVERAGE POSITION ANDPEAK TO PEAK ERRORS- TRANSFORM THE NAD 83 (2011) COORDINATES FROM THE SESSION MIDPOINT TOTHE DATUM EPOCH OF JANUARY 1, 2010.

http://www.ngs.noaa.gov/TOOLS/Htdp/Htdp.shtml

OPUS-S COMPUTATIONS

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THE VALUE OF OPUS SAVED THIS SURVEYOR’S LICENSE AND BUSINESS! OPUS ONBENCH MARKS IS ALSO VALUABLE TO PLACE ACCURATE POSITIONS ON LOCATIONSTHAT COULD BE JUST SCALED FROM TOPO MAPS. THIS AIDS IN THE MONUMENT’SRECOVERY (AND LOCATES THE BENCH MARK ACCURATELY FOR INPUT INTO THE GEOIDMODELING DONE BY NGS)

RSGPS PROCESSING ENGINE

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RAPID-STATIC: OPUS FIRST CREATES AN ATMOSPHERIC DELAY MODEL FROMSURROUNDING CORS DATA.

YOUR POSITION IS THEN QUICKLY DETERMINED BY DIFFERENTIAL GPSSTATIC SOLUTION.

OPUS- RS- SIMILAR TO A RTN APPROACH

OPUS Rapid−Sta� c handles data spans shorter than 2 hrs. It uses additional datafrom the CORS surrounding your mark tocompute charged and neutralatmosphere corrections at the CORS. Itthen interpolates those values to yourmark’s location. Using the interpolatedcorrections, the integers and thecoordinates can be confidentlydetermined.

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OPUS-RS

• OPUS-RS USES RSGPS IN TWO MODES:NETWORK AND ROVER

• IN NETWORK MODE, AT LEAST ONE HOUR OF DATA FROM THE SELECTED CORSARE USED TO SOLVE FOR AMBIGUITIES, TROPOSPHERIC REFRACTION, ANDDOUBLE DIFFERENCE IONOSPHERIC DELAYS AT THESE CORS. THE POSITIONS OFTHE CORS ARE HELD FIXED.

• IN ROVER MODE, IONOSPHERIC DELAYS AND TROPOSPHERE PARAMETERS AREINTERPOLATED (OR EXTRAPOLATED) FROM THE SELECTED CORS TO ROVER.THEN THE DELAYS AT THE ROVER ARE CONSTRAINED TO SOLVE FOR THEPOSITION OF THE ROVER. AGAIN, THE POSITIONS OF THE CORS ARE HELDFIXED.

• RSGPS IS BASED (CONCEPTUALLY) ON THE MPGPS

PROGRAM DEVELOPED AT THE OHIO STATE UNIVERSITY.

• 15-minute sessions (max = 2 hours)

• ties to 3 – 9 CORS (< 200km)

• uses RSGPS vs. PAGES software

• P1/P2 code & L1/L2 phase observations

• resolves all ambiguities with LAMBDA

• similar to Real-Time Network computations

• RSGPS solution modes:

– network: solves ambiguities, tropo, iono

– rover: tropo and ion interpolated to rover

• ~10,000 lines of code

OPUS-RS

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OPUS-RS SEARCH ALGORITHM

•SORT STATIONS IN CORS NETWORK BY DISTANCE FROM ROVER. SELECT UP TO SIX CORS THATARE LESS THAN 200 KM FROM ROVER AND THAT HAVE SUITABLE DATA.

•NO SOLUTION IS ATTEMPTED IF FEWER THAN THREE CORS SELECTED.

•NO SOLUTION ATTEMPTED IF DISTANCE FROM ROVER TO POLYGON ENCLOSINGSELECTED CORS IS GREATER THAN 50 KM.

200 km limit

<50 km

http://www.ngs.noaa.gov/OPUSI/Plots/Gmap/OPUSRS_sigmap.shtml

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OPUS-RS ACCURACY

OPUS-RS ACCURACY

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OPUS-RS ACCURACY

OPUS-RS ACCURACY

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OPUS-RS ACCURACY

OPUS-RS ACCURACY

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https://beta.ngs.noaa.gov/opusmap/

https://www.ngs.noaa.gov/OPUS/view.jsp

SIMPLE IS BETTER!

Files used:

(create, sort, maintain)

Required Metadata

(input)

Programs used:

(learn, run, maintain)

BLUEBOOK 16 filesxxxxxxxxxxxxxxxx

378 elementsxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

26 programsxxxxxxxxxxxxxxxxxxxxxxxxxx

OPUS-DB2 files

xx

(GPS data + photo)

15 elementsxx

1 programx

(internet browser)

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THE OPUS SHARING OPTION.

2011-06-20 59

HOW DO I SHARE MY RESULTS?

GO TO THE OPUS UPLOAD PAGEAND FILL OUT THE FORM AS YOUNORMALLY WOULD, BUT BEFORECLICKING THE UPLOAD BUTTON,CLICK THE OPTIONS BUTTONCAUSING THE OPTIONS TO APPEAR.

SELECT “YES, PUBLISH” FOR THE“PUBLISH MY SOLUTION” OPTION.

NOW CLICK UPLOAD.

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STABLEPERMANENTUNIQUERECOVERABLESAFE

Z 125

1935--|--

control stationmonument

CONTROL STATION REQUIREMENTS

WHY A PASSIVE MARK?

• A PLACEHOLDER FOR A SURVEY OBSERVATION

• A CONNECTION TO PRIOR SURVEYS

• A NETWORK OF INTERCONNECTED SURVEYS

• A POSITIONAL FRAMEWORK: ACCESS TO NSRS

• AN AZIMUTH & DISTANCE STANDARD TO ADJUST LOWER ACCURACYSURVEY WORK.

• A CONFIDENCE CHECK

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OPUS statistics checked by computerPhotos reviewed by NGSDatasheet reviewed by agency

QUALITY CONTROL

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OPUS REGISTRY

https://geodesy.noaa.gov/OPUS

REGISTRATION STORES THE FOLLOWING:•NAME

•ADDRESS•AGENCY

•EXPERIENCE- GPS & OPUS

OPUS-DB

OPUS-DB CAN BE USED TO UPGRADE A HORIZONTAL POSITION FROM ASCALED VALUE PERHAPS 100’S OF FEET IN ERROR TO ONE THAT IS ONLY AFEW CENTIMETERS IN DOUBT.

OPUS-DB IS USED TO VERIFY THAT RTN STATIONS ARE ALIGNED TO THENSRS WITHIN TOLERANCE PARAMETERS (BETA NGS PROGRAM)

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https://beta.ngs.noaa.gov/opusmap/

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EACH RTN WILL BE REPRESENTED BY ONE SYMBOL

USING OPUS-SHARED FOR THE NGS RTN VALIDATION TOOL(OPERATIONAL PROTOTYPE)

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THE SYMBOLS EXPAND TO SHOW THE RTN STATIONS

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OPUS-S OUTPUT• > 90% observations used

• > 50% ambiguities fixed

• < 3 cm overall RMS

• < 5 cm peak-to-peak errors

• check antenna info

• check ephemeris type

…and which CORS were used? …might wait and resubmit for improved CORS scenario

BM02121A.13o

OPUS-S STANDARD & EXTENDED OUTPUT

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USING AUSPOS(GEOSCIENCE AUSTRALIA)

FOR A REDUNDANT POSITION COMPUTATION

≥ 1 HOUR OF DUAL FREQUENCY DATA

OPUS vs. AUSPOS4 HOURS OF DATA ON A KNOWN POINT

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NGS OPUS-RS SOLUTION REPORTUSER: william.stone@noaa.gov DATE: October 29, 2007

RINEX FILE: 1207287x.07o TIME: 14:39:04 UTC

SOFTWARE: rsgps 1.09 RS11.prl 1.12 START: 2007/10/14 23:27:15

EPHEMERIS: igr14490.eph [rapid] STOP: 2007/10/15 00:00:15

NAV FILE: brdc2870.07n OBS USED: 1962 / 2082 : 94%

ANT NAME: ASH701975.01A QUALITY IND. 34.21/ 37.91

ARP HEIGHT: 0.0 NORMALIZED RMS: 0.307

REF FRAME: NAD_83(CORS96)(EPOCH:2002.0000) ITRF00 (EPOCH:2007.78627)

LAT: 36 2 52.79767 0.008(m) 36 2 52.81498 0.008(m)

E LON: 252 2 18.45532 0.013(m) 252 2 18.41156 0.013(m)

W LON: 107 57 41.54468 0.013(m) 107 57 41.58844 0.013(m)

EL HGT: 1974.304(m) 0.005(m) 1973.396(m) 0.005(m)

ORTHO HGT: 1995.280(m) 0.026(m) [Geoid03 NAVD88]

OPUS-RS OUTPUT

*

“#FIXED AMBIGUITIES” REPLACED BY “QUALITY INDICATOR”•AVERAGE OF W-RATIO (SEPARATION BETWEEN CANDIDATE SETS OF AMBIGUITIES)OF LAST 3 EPOCHS•REPORTED AS NETWORK MODE / ROVER MODE•LOOK FOR VALUES > 3 FOR CONFIDENCE IN SOLUTION

NGS OPUS-RS SOLUTION REPORTUSER: william.stone@noaa.gov DATE: October 29, 2007

RINEX FILE: 1207287x.07o TIME: 14:39:04 UTC

SOFTWARE: rsgps 1.09 RS11.prl 1.12 START: 2007/10/14 23:27:15

EPHEMERIS: igr14490.eph [rapid] STOP: 2007/10/15 00:00:15

NAV FILE: brdc2870.07n OBS USED: 1962 / 2082 : 94%

ANT NAME: ASH701975.01A QUALITY IND. 34.21/ 37.91

ARP HEIGHT: 0.0 NORMALIZED RMS: 0.307

REF FRAME: NAD_83(CORS96)(EPOCH:2002.0000) ITRF00 (EPOCH:2007.78627)

LAT: 36 2 52.79767 0.008(m) 36 2 52.81498 0.008(m)

E LON: 252 2 18.45532 0.013(m) 252 2 18.41156 0.013(m)

W LON: 107 57 41.54468 0.013(m) 107 57 41.58844 0.013(m)

EL HGT: 1974.304(m) 0.005(m) 1973.396(m) 0.005(m)

ORTHO HGT: 1995.280(m) 0.026(m) [Geoid03 NAVD88]

OPUS-RS OUTPUT

*

“OVERALL RMS” REPLACED BY “NORMALIZED RMS”•UNITLESS QUANTITY, “EXPECTED” = 1•AKA STANDARD DEVIATION OF UNIT WEIGHT•IF > 1, NOISY DATA SOMEWHERE•TYPICALLY <1, MEANING NOISE LESS THAN EXPECTED

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NGS OPUS-RS SOLUTION REPORTUSER: william.stone@noaa.gov DATE: October 29, 2007

RINEX FILE: 1207287x.07o TIME: 14:39:04 UTC

SOFTWARE: rsgps 1.09 RS11.prl 1.12 START: 2007/10/14 23:27:15

EPHEMERIS: igr14490.eph [rapid] STOP: 2007/10/15 00:00:15

NAV FILE: brdc2870.07n OBS USED: 1962 / 2082 : 94%

ANT NAME: ASH701975.01A QUALITY IND. 34.21/ 37.91

ARP HEIGHT: 0.0 NORMALIZED RMS: 0.307

REF FRAME: NAD_83(CORS96)(EPOCH:2002.0000) ITRF00 (EPOCH:2007.78627)

LAT: 36 2 52.79767 0.008(m) 36 2 52.81498 0.008(m)

E LON: 252 2 18.45532 0.013(m) 252 2 18.41156 0.013(m)

W LON: 107 57 41.54468 0.013(m) 107 57 41.58844 0.013(m)

EL HGT: 1974.304(m) 0.005(m) 1973.396(m) 0.005(m)

ORTHO HGT: 1995.280(m) 0.026(m) [Geoid03 NAVD88]

OPUS-RS OUTPUT

* *

PEAK-TO-PEAK REPLACED BY EST. STANDARD DEVIATIONS•APPROXIMATELY 95% CONFIDENCE•DERIVED FROM SCATTER OF SINGLE BASELINE SOLUTIONS•FORMAL STANDARD DEVIATIONS (OPTIMISTIC) AVAILABLE IN EXTENDED OUTPUT

OPUS-RS STANDARD & EXTENDED OUTPUT

opusRSEXTENDED.txt

G0000001 .05o

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N E h H

CORB: PUBLISHED (OLD) 2060045.533 3598666.726 37.252 "CORB" REFLECTS A PERFECT SCENARIO FOR A

CORB: 8 HOURS AS "TRUTH" 2060045.532 3598666.740 37.239 POINT POSITIONSOLUTION D N D E D h NOTES

DAY 92

OPUS-S: 1ST 4 HOURS 0.000 -0.002 0.005THESE ARE NOT INDEPENDENT OBSERVATIONS

OPUS-S: 2ND 4 HOURS 0.001 -0.002 -0.011THEY SHOW DIFFERENCES WITH SLICING A PIECE OF

OPUS-S: 1ST 2 HOURS -0.005 -0.003 -0.005THE PIE, AND PROCESSING WITH THE TWO PROGRAMS

OPUS-RS: 1ST 2 HOURS 0.006 -0.007 0.002 "

OPUS -S: LAST 2 HOURS -0.004 0.003 0.015 "

OPUS-RS: LAST 2 HOURS 0.004 -0.005 0.011 "

OPUS-RS: 1ST 1 HOUR 0.009 -0.008 0.008 "

OPUS-RS: LAST 1 HOUR 0.006 -0.007 -0.009 "

OPUS-RS: 15 MINUTES 0.009 -0.006 -0.005 "

SOME OPUS COMPARISONS WITH A “PERFECT” SITE-AVERAGING PRODUCES RESULTS CLOSEST TO THE TRUTH

DAY 69

OPUS-S: 9 HOURS -0.001 -0.004 0.000 THESE ARE NOT INDEPENDENT OBSERVATIONS

OPUS-S:MID 2 HOURS 0.012 -0.010 -0.021 THEY SHOW DIFFERENCES WITH SLICING A PIECE OF

OPUS-RS: MID 2 HOURS 0.008 -0.008 0.000 THE PIE, AND PROCESSING WITH THE TWO PROGRAMS

OPUS-S: 2 HOURS -0.014 0.013 -0.003 "

OPUS-RS: 2 HOURS 0.010 -0.009 0.022 "

OPUS-RS: 1 HOUR 0.010 -0.010 0.002 "

2011 DAY 335

OPUS-RS: 15 MINUTES 0.009 -0.008 -0.005 THESE ARE NOT INDEPENDENT OBSERVATIONS

OPUS-RS: 1 HOUR 0.006 -0.008 -0.017 THEY SHOW DIFFERENCES WITH SLICING A PIECE OF

THE PIE, AND PROCESSING WITH THE TWO PROGRAMS

COMPARISON WITH 3/9/12 & 12/1/11

THEREFORE: EXPECT A “COUPLA” CM FOR ELLIPSOID HEIGHT SOLUTIONS EVENWITH A “PERFECT” SITE

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FABULOUS, FREE – BUT:1. NEEDS 2 HOURS OR MORE PER OCCUPATION2. NEED TO COMPLETE 2-DAY MANAGER TRAINING

1. CREATE A PROJECT, SET PROJECT PARAMETERS

2. COLLECT DATA AND METADATA (PHOTOS AND MARKDESCRIPTIONS)

3. LOAD THE DATA

4. PROCESS THE DATA

5. PERFORM A NETWORK ADJUSTMENT

6. PUBLISH (IF DESIRED)

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OPUS SOLUTIONS = PRETTY GOOD, BUT EACH TREATED AS INDEPENDENTAND ASSUMES “PERFECT” CORS.

SESSIONS = SIMULTANEOUSLY-OBSERVED MARKS PROCESSEDTOGETHER IN SESSIONS INCREASES CONSISTENCY.

ADJUSTMENTS = INTERLINKING SESSIONS THROUGH NETWORKADJUSTMENTS INCREASES ACCURACY.

PROCESSING AND ADJUSTMENT PLOTS

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• UPLOADS THROUGH OPUS-STATIC.– DUAL-FREQUENCY.– 2 HRS ≤ DATA SPAN ≤ 48 HRS (≤ 2 GPS MIDNIGHTS).– OBSERVATION INTERVAL = A FACTOR OF 30 (SECONDS).– GPS ONLY

• MINIMUM PROJECT SIZE.– NONE

• MAXIMUM PROJECT SIZE.– THERE ARE PRACTICAL LIMITS TO A PROJECT’S MAXIMUM SIZE.– ABOUT 100 MARKS IN A SINGLE SESSION.– NUMBER OF DATA FILES < A FEW HUNDRED.

5 GUIDING PRINCIPLES

1. PRECISION IS INDEPENDENT OF BASELINE LENGTH

2. PRECISION DEPENDS ON OBSERVATION SPAN

3. SESSION NETWORK DESIGNS MUST INCLUDE BOTH SHORT AND LONGBASELINE LENGTHS

4. GNSS MEASUREMENT ERRORS ARE INDEPENDENT, THEY DO NOTPROPAGATE THROUGH A NETWORK

5. RELATIVE POSITIONS MUST BE WITH RESPECT TO A SINGLEREFERENCE MARK OR REFERENCE NETWORK

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ALTHOUGH IT MAY SEEM COUNTER-INTUITIVE, INCLUDING DISTANT CORSENABLES BETTER NEUTRAL ATMOSPHERE CORRECTIONS, WHICH MAKES FORA BETTER SOLUTION.

MORE CORS MINIMIZES THE EFFECTS OF MISSING DATA FROM ANDCHANGES AT THE CORS USED IN YOUR SOLUTION.

FURTHERMORE, THIS ALLOWS OPUS-NET TO EMPHASIZE “QUALITY” AS WELLAS “QUANTITY.” THE BEST UNDERSTOOD CORS IN NORTH AMERICA (ANDTHE WORLD) WILL ALWAYS BE USED IN THE PROCESSING.

WHY USE NEAR AND DISTANT CORS?

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Adobe Acrobat

Document

FAIRFAX COUNTY, VA.HEIGHT MOD PROJECT145 stations- 42 new- 69 existing-13 HARN- 16 vertical (11 eccentric)

515 baselines

OBSERVATIONPLANNING:

HTMOD SESSIONS TOCONNECT CLOSEST

NEIGHBORS

HTMOD CONTROLSURVEYS:LARGE AREAS,MUNICIPALITIES, LONGPIPELINES, ETC.

WHEN TO USE STATIC GNSSMETHODS?

46

EXAMPLE 1: CONNECT MARKS DIRECTLY TO HUBS.

No Yes

2014-05-29 91Suggested Processing Guidance

No

Yes

+

+

EXAMPLE 2: CREATE A SINGLE REFERENCE NETWORK.

Session 1 Session 2

Session 1 Session 2

Network

Network

47

INCLUDED CORS• ONLY ONE, OR A FEW AT MOST, CORS WILL BE HUBS.

• DISTANT CORS MUST BE INCLUDED IN ALL SESSIONS FORTROPOSPHERE DECORRELATION.

• THE INCLUDED CORS, PARTICULARLY THOSE USED AS HUBS, SHOULDBE PRESENT IN ALL SESSIONS.

• ALTHOUGH IT IS NOT NECESSARY TO USE ALLCORS UPLOADED BY OPUS, MORE INCLUDED CORS IMPLIES LESSDEPENDENCE ON A SINGLE CORS AND A BETTER TIE TO THE NSRS.

AFTER A MOMENT, AN INTRODUCTION TO YOUR NEWLY CREATED PROJECT WILL BESHOWN. IT CONTAINS INFORMATION NECESSARY FOR YOU TO WORK WITH YOURPROJECT. YOU’LL ALSO RECEIVE THIS INFORMATION IN EMAIL. SAVE THIS EMAIL FORFUTURE REFERENCE.

EVERYBODY NEEDS TO KNOW THIS TOUPLOAD DATA

FOR THE MANAGER ONLY. CONTROLOVER ALL ASPECTS

FOR SOMEONE ELSE TO PROCESS DATA

LINK TO MANAGER’S PAGE.

48

YOU’LL BE TAKEN TO THE MANAGER’S PAGE FOR YOUR EMPTY PROJECT.

CONTROLS

VIEWSELECTION

MARK & CORSDISLAY

48 states now have laws that refer to NAD 83 by nameA name which will be retired in 2022

NSPS will work with the states to adopt the new templatebetween 2017 and 2022

49

THE SHORTCOMINGOF NAD 83….

• MOVE GEOCENTER TO IGS GEOCENTER AT SOME EPOCH OF TIME.COORDINATES WILL BE IDENTICAL TO IGS AT THIS EPOCH OF TIME, BUT WILLTHEN DIVERGE, BECAUSE:NATRF2022 WILL BE FIXED ON NORTH AMERICAN PLATE (RELATIVE TOROTATION ABOUT THE EULER POLE) AND NOT CHANGE RELATIVE TO CRUSTALMOTION.

• THERE WILL BE AN INTRA-FRAME VELOCITY MODEL (IFVM) TO ACCOUNT FORNON-EULERIAN MOVEMENT.

50

CHANGE IN “h”

51

1. BIASED TO THE GLOBAL GEOID MODEL BY ABOUT 0.5 M2. BENCH MARKS ARE ALMOST NEVER RE-CHECKED FOR MOVEMENT3. DISAPPEAR BY THE THOUSANDS EVERY YEAR4. WERE DETERMINED BY LEVELING FROM A SINGLE POINT, ALLOWING CROSS-COUNTRY ERROR BUILD UP (~ 1 METER)

• ARE NOT FUNDED FOR REPLACEMENT•ARE NOT NECESSARILY IN CONVENIENT PLACES•DON’T EXIST IN MOST OF ALASKA•WEREN’T ADOPTED IN CANADA

THE SHORTCOMING OF NAVD 88….WHY ISN’T NAVD 88 GOOD ENOUGH ANYMORE?

RE-LEVELING WOULD COST 200 MILLION TO 2 BILLION $$

….THE TILT OF NAVD 88 RELATIVE TO THE GRAVIMETRICGEOID

102

NAVD 88 = 0.00

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• BASED ON PURE GRAVIMETRIC GEOID, ACCURATE TO≈1 CM VIA GRAV-D PROJECT

• VERTICAL DATUM BROUGHT TO SITE AT ≈2 CM IN WELL-MODELED AREAS. ACCURACY (ALLOWS 1 CM “h” ERROR)

• ACCESSABILITY: BROUGHT TO A PROJECT SITE VIA ACTIVE REFERENCESTATIONS (NATIONAL CORS)

• DENSIFIED TO PROJECT ACCURACY NEEDS AT SITE (E.G., DIGITAL LEVELING).

NAVD 88 WILL BE ABOUT 1.3’ GREATER INVALUE THAN THE NEW NAPGD2022 VERTICALDATUM IN NEW YORK

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IMPROVING OPUS RESULTS

• GET REDUNDANT OCCUPATIONS WITH DIFFERENT SATELLITE GEOMETRY TOINCREASE CONFIDENCE WITH THE POSITION.• OBSERVE LONGER.• CHECK WEATHER AND SPACE WEATHER TO ENSURE THERE ARE NO SIGNIFICANTWEATHER FRONTS OR GEOMAGNETIC STORMS AFFECTING THE CORS STATIONS USED.• WAIT FOR RAPID OR EVEN FINAL ORBIT DATA TO BE AVAILABLE AND REPROCESS.• CONVERT THE OBSERVATION DATA INTO RINEX FORMAT, SEGMENT A LONGOBSERVATION INTO 2-HOUR SECTIONS AND SUBMIT THESE TO OPUS-RS TO COMPARETHE RESULTS FROM THE TWO PROCESSING PROGRAMS.

OPUS KEY WORD IS “TIME”, RT KEY WORD IS “REDUNDANCY”STATIC KEY WORD IS “STATISTICS”

CAVEATS FOR USING OPUS• STORM FRONTS

• IONO DISTURBANCE

• BIASES AT CORS STATIONS

• WRONG ANTENNA MODEL. CHOOSING AN INCORRECT ANTENNA MAY RESULT INUNACCEPTIBLE HEIGHT ERRORS.

• NO VERIFICATION OF OCCUPIED POINT

• ORTHOMETRIC HEIGHT IS ONLY AS GOOD AS THE HYBRID GEOID MODEL AT THEOCCUPIED POINT

• NO NETWORKED ADJUSTMENT

• WEAK GEOMETRY FOR OPUS-RS

• EXTRAPOLATION VS. INTERPOLATION WITH OPUS-RS

• MULTIPATH AT OCCUPIED POINT COULD GIVE VARIATION IN SOLUTIONS

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OPUS POINTS TO KEEP IN MIND….•OPUS ARE SINGLE POINT POSITIONS NOT NETWORKED “SESSIONS”

•OPUS LIKES LONGER TIME DATA

•USE BOTH OPUS-S AND OPUS-RS FOR QUALITY CHECKS

•ORTHOMETRIC HEIGHTS ARE DEPENDENT ON THE QUALITY OF THE HYBRID GEOID MODEL

•OPUS SOLUTIONS CAN VARY A “COUPLA” CM – EVEN WITH THE SAME DATA SET

•OPUS REFERENCE STATIONS CAN BE HAND PICKED OR REMOVED FROM A SOLUTION SET

•“0” ANTENNA HEIGHT RETURNS THE ARP

•“NO ANTENNA” RETURNS BEST FIT L1 PHASE CENTER AND POSSIBLE DECIMETER LEVEL ERRORS

NYSAPLS 2018 WORKSHOPS: DATUMS , GNSS FOR PROJECTCONTROL, USING OPUS

MANY MORE TOPICS AT: http://www.geo-learn.com/