Height Modernization Coordination Meeting

USGS GNSS T&M Why?

Technique and Approach Guidance For USGS Accuracy and Precision Metadata Example Campaigns and Decision Trees Future Direction Consistent and Referable

With the new Trimble R8 systems, we are getting vertical accuracies within 7 mm as statedin the data collector RTK can only be usedwhen setting up directly over a benchmark Real-Time Network surveys pretty much guarantee vertical accuracies within 2 cm and you never need a base station All post processing GPS surveys must ensure 6 hours of data collection at a minimum

USGS GNSS T&M - Introduction

Historic USGS Datum Establishment

Evolution GPS Modernization GNSS GLONASS, Galileo, Compass

Geodesy Background

GNSS T&M - Equipment

USGS GNSS T&M - Mission Planning PDOP Multipath Ionosphere & Troposphere Satellite Availability (Notice Advisory To Navstar Users) Space Weather (Space Weather Prediction Center) Resolution and Accuracy of Local Geoid

GNSS T&M Real Time (RT) Surveys

Single Base RTNetwork Base RT

GNSS T&M Real Time (RT) Surveys

Quality AssurancesBlunder CheckMultipath and GeneralHeightReinitializationBlunder Check -Lets sum it up!Collectively, the GNSS user observes 180 epochs or 3 minutes of data, walks away from the objective point a minimum of 100 feet, inverts the rover receiver (or adjusts the elevation mask) to lose initialization, changes the rover rod height at least 0.80 feet and corrects the rover height entered in the data collector appropriately, walks a different approach path back to the objective point, then positions the rover receiver in an upright position over the objective point for the second observation. Both observations are averaged to produce the final result. This process is hereinafter referred to as a RT blunder check and should be recorded in the field notes to document that these redundant assurances are met.

GNSS T&M Real Time (RT) SurveysLocalizations / Realizations

USGS GNSS T&M Post Processed

Single Base OPUS Traditional Static Rapid Static

The experts ingeodesy.The USGS GNSS T&M Manual recommends and encourages use of this online utility

USGS GNSS T&M Post Processed

Network Surveys

Quality AssurancesModified from NOS NGS 59 Tech Memo

USGS GNSS T&M Quality Categorization

Level I Static Network Survey Control 40 Km spacing; 4 hour; 2nd order or better Objective 15 Km spacing; 1 hour; 50% double occupied Additional benchmark checks other than primary control

Level I Static Single Base Survey (OPUS-S) Occupation 2 Days, 4 hours, different times Quality Indicators


Level II Static Network Survey Control Points 60 Km spacing; 4 hour; 2nd order or better Objective Points 25 km spacing; 1 hour; 50% double occupied Additional benchmark checks other than primary control

Level II Static Single Base Survey (OPUS-S) Occupation 1 day 4 hours Quality Indicators Level II RT Surveys Localization 2nd order or better Satellites; PDOP; baseline length Blunder check redundancy within 0.03 m Objective points 10% double occupied (within 0.05m)


Level III Static Single Base Survey (OPUS-S) Quality Indicators Level III Static Single Base Survey (OPUS-RS) Quality Indicators Level III RT Surveys Localization 3rd order or better Satellites; PDOP; baseline length Blunder check redundancy within 0.04 m Objective points 10% double occupied; within 0.05m


Level IV Generally reserved for RT topographic surveys without checks Can be composed of static surveys without quality indicators or checks

USGS GNSS T&M Quality How Do We Get There?

USGS GNSS T&M Metadata (documentation of the geodetic trail)

RecoveryEstablishment

Benchmark

USGS GNSS T&M Metadata (documentation of the geodetic trail)

Observation Database storage lat-long and altitude metadata

USGS GNSS T&M Example Data Set (Groundwater Well Field)

USGS GNSS T&M Example Data Set (Flood Study)

USGS GNSS T&M Example Data Set (Streamgage Datum)

USGS GNSS T&M Future Direction of GNSS

Modernization programs L5 signal GRAV-D Precise Point Positioning (PPP)

Plug for USGS GPS Committeehttp://water.usgs.gov/usgs/osw/gps/

Office of Employee Development (OED) ID1747

Application and Practice of Survey-Grade GNSS Real-Time and Static Surveys in the USGS


Application and Practice of Survey-Grade GNSS Real-Time and Static Surveys in the USGSSyllabus


Application and Practice of Survey-Grade GNSS Real-Time and Static Surveys in the USGSOPUS Projects

PROJECT APPLICATION Storm Surge Sensors The New Madrid FloodwayLevee Breach

PROJECT APPLICATION Storm Surge Sensors Whats up with Sandy

Legacy Datum - Mississippi River Datum and Some TributariesMemphis DatumMean Gulf DatumFourth General Adjustment of 1912

Historic datum is considered legacy

Legacy Datum Middle Mississippi River Datum St. Louis Gaging StationHistoric datum is considered legacy

Middle Mississipppi River Gage Hydralic DatumsDatum ConversionsZero GageSt Louis Direatrix413.68-33.74Cario400.23-20.29Memphis387.107.16Mean Sea Level379.94St Louis Gage0Mean Gulf379.800.14Engineers Office213.68166.26

NAVD 88 Datum Conversion : Simple Height Conversion or Survey The USGS Missouri Model1. Evaluation of Source Datum 2. Cooperative Interest 3. Hydraulics and Stability

4. Accuracy assured with USACE CEPD and NWS modeling interests

Missouri River Datum DiscrepancyExampleInter-Agency Collaboration in Missouri

Benefits of Inter-Agency CollaborationEnhance Resources

Reduce Expense

Quality Assurance

Agency Consensus Public Approval

Continuing Inter-Agency Collaboration in MissouriDatum Surveys Moving Forward

USGS and USACE duplicative surveys at important gaging locationsMain stem Missouri and Mississippi River gagesWater resource operation project gagesLimited duplication at tributary gages USGS / USACE surveysSharing of metadata and resultsOvercome cost prohibitive gaging locationsAugmenting staff for local/regional GNSS campaigns

USGS Gaging InstallationInstallation of an observable benchmark

Continuing Inter-Agency Collaboration in MissouriSurvey assistance.MODOTMDNR

Continuing Inter-Agency Collaboration in Missouri FY 13USGS Missouri Water Science Center Observations per T&M (Level I)USACE SWLUSGS - MOWSCUSGS - ARWSC

Single Base OPUS Level I Quality - SWL Augment SurveyGaging Station NumberGaging Statiion DescriptionObservation DateTimeObsevations UsedRequiredAmibiguities FixedRequiredSolution RMS (m)Required (m)Vertical peak-to-peak (m)Required (m)Orthometric HeightAverage Ortho Height (m)Within 0.05m of each solution7058000Bryant Creek near Tecumseh, MO10/16/20121137 - 170391%>80%94%>80%0.01580%0.01780%0.01580%0.01780%0.01280%0.01380%0.01280%0.01380%0.01380%0.013

Continuing Inter-Agency Collaboration in Missouri FY 13

Inter-Agency CollaborationDatum Surveys Assistance and Collaborationhttp://www.ngs.noaa.gov/ADVISORS/AdvisorsIndex.shtml

Inter-Agency [email protected] Surveys Assistance and Collaboration

Questions ?

Early usage of GPS in GS for Earthquake monitoring and orthophoto control.

Modernization of new civilian signals L2C, L5 with Block IIF satellite series. Add to existing GPS network 24+3. GLONASS traditional L1/L2 but with oncoming modernization for L5. GIOVE test satellites in orbit for Galileo; L5 signal; Beidu satellites from existing system.Micro-centered antennas, those with built in choke rings, those with less multipath protection; many new integrated receivers have that technology built inCalibration method; both fixed height tripod and bipod (rover pole)Atmospheric variation and disturbance of ionosphere (May 2013 anticipated solar energetic peak)

Table of residual differences between GPS-derived ellipsoidal and leveled orthometric height data vs. the hybrid geoid. Should be noted results are illustrated at the 68.5% or one sigma confidence interval. Need to nearly double for 95% confidence interval.

Affects accuracy of GNSS measurements by causing a delay in GPS signal Distortion of signal varies with thickness of layer and activity of charged particles Baselines < 10 km (6 miles) - effects are almost equal at base and rover and typically dont require ionospheric modeling

Assurance of broadcast radio communication; extended range antenna (PPM error cautioned with RTK baseline length). Be weary of solutions that are not fixed in a normal amount of time. Redundancies (protocol thereof). Assurance of broadcast radio communication; extended range antenna (PPM error cautioned with RTK baseline length). Be weary of solutions that are not fixed in a normal amount of time. Redundancies (protocol thereof). Assurance of broadcast radio communication; extended range antenna (PPM error cautioned with RTK baseline length). Be weary of solutions that are not fixed in a normal amount of time. Redundancies (protocol thereof). OPUS; obss used, ambiguities resolved, vertical peak-to-peak, RMSRS Normalized RMS

OPUS; obss used, ambiguities resolved, vertical peak-to-peak, RMSRS Normalized RMS

40 Km spacing between 2nd or BMs, 4.0 hour BM occupations, 15 km spacing and 1 hour obj point occupations - 50% double occupied. Additional benchmarks checked.

OPUS occupations to ensure variability in atmospheric conditions. Criteria set regarding Obss used, ambiguities fixed, peak-to-peak error, RMS

Average of both OPUS solutions should be within 0.05 m of either solution.

40 Km spacing between 2nd or BMs, 4 hour BM occupations, 15 km spacing and 1 hour obj point occupations - 50% double occupied. Additional benchmarks checked.

Criteria set regarding Obss used, ambiguities fixed, peak-to-peak error, RMS

Note that for single base RT positioning, 10% of objective points need to be observed from a different base receiver location and those observations should not vary more than 0.05m.

Criteria set regarding Obss used, ambiguities fixed, peak-to-peak error, RMSCriteria set regarding normalized RMS

Note that for single base RT positioning, 10% of objective points need to be observed from a different base receiver location and those observations should not vary more than 0.05m.

Lat/long accuracy (C11, coord_acy_cd) (documentation will state that these codes should be used when C35 = survey-grade GPS): C - Level 1 survey-grade GPS D - Level 2 survey-grade GPS E - Level 3 survey-grade GPS F - Level 4 survey-grade GPS Lat/long method (C35, coord_meth_cd): F - Survey-grade GPS Altitude method (C17, alt_meth_cd): F - Survey-grade GPS

Talk about linking with NGS-IDB to extract station recovery notes, to utilize in USGS Mapper.

L5 signal

1. Broadcast strength is 4x more powerful than L2C.2.Further frequency separation from L1 and L2 for enhanced ionosphericcorrection.3.Longer code and error-correcting techniques for more robust tracking in difficult environments. 4.Supported by other global GNSS (Galileo, Compass, SBAS).5.Located in the highly-protected aeronautical band

Discuss L1 v. L2, struggles in Arkansas. L5 nearly 4x L2

IIF with additional 11 L5 signal satellites are due by 2014/2015. And.. If all 12 GPS IIF satellites are in orbit by 2014/2015 and 18 Galileo satellites are in orbit by 2014/2015, then there will be 30 satellites broadcasting L1/L5 (Galileo doesnt support L2) in less than five years from now.

Budget:Both GPS and Galileo face budget challenges, albeit for different reasons. For GPS, the legacy satellites are performing better than predicted and each satellite launch costs in excess of $100M, theres pressure to delay launching newer satellites. For Galileo, a publicly-funded endeavor involving 27 member countries, the complexity of funding and managing such a program is staggeri

GLONASS was designed as a FDMA system instead of CDMA like GPS, Galileo and Compass. Russia has committed to transition to CDMA, but it takes time.GLONASS has announced L5 support, but the roadmap is vague and 2015 or later.GLONASS is very valuable to high precision users today, but its value will likely diminish as other GNSS like Galileo and Compass emerge.Compass is emerging and could be a wild card.Copyright

With PPP..increased observations overcome convergence time and thus promote accuracy. Upon further algorithim development, technology could be commensurate with RTK.New additions for GS GNSS

FCC license and narrowband requirements

New additions for GS GNSS














Discussion of Pauls experience of the procedure and lessons learned. Add SSS recovery regarding Hurricane Sandy and other historic storm surge sensors.Add SSS recovery regarding Hurricane Sandy and other historic storm surge sensors. Reflect on the integration of NGS Advisor (Denis Riordan) and others. Some training.Memphis datum arbitrary datum used in the latter part of the 19th century established in Memphis Tn. Mean Gulf Datum First sea level datum for Mississippi from a tide gage based in Biloxi by the Mississippi River Commission 1881. Forth General Adjustment of 1912 First datum based on geodetic quality leveling by USC&GS held fixed at (5) tide stations.

Chris Pearson (NGS Advisor) has a good ASCE paper Legacy Height Datums on the Miss and Illinois River Systems

Legacy or source datum evaluation (2) Cooperative interest in gaging location (e.g. forecast, water control operations, flood protection) (2) hydraulics and stability assessment of the gaging location (3) 0.1 foot tie satisfies NWS mod

Discuss St. Joe - Missouri River Datum Predated 29 Adjustmentetc. This is a good example that should mitigate the scare of public outcry. No phone calls to NWK, MOWSC, or EAX.

EAX comments, had to pay 4K for web contractor to update web page, sent out a public information statement.Limited resources from agencies, adding personnel to support efforts in the local or other. Simply combining resources adds to the completion of the effortLimited budgets prevent personnel from conducting datum ties to all gaging stationsQuality assurance as a checked effortAgency consensus for inter-agency efforts or operationsPublic approval, more likely having collaborationNote limited involvement for USACE tributaries (regarding redundant efforts). However, USGS obligations are to forecast locations and/or cooperative interest.Many gaging locations are cost prohibitive to survey datum. That being the case, staff from USACE may be in the area to support USGS or conversely. Augmenting staff is simply supplying GNSS equipment and personnel to support GNSS network surveys that can be expanded to benefit the USGS (maybe nearby streamgages) and USACE for dam deformation or other water resource project efforts.A benchmark will be established at all new USGS gaging stations (grout in headwall or bridge or establish in R/W).Using these maps, an effort in the SW corner of Missouri may enlist survey support from USACE, MoDOT, & MDNR. Guidelines would have to be adhered to using the GS manualbut all agencies are cooperators in this effort.Using these maps, an effort in the SW corner of Missouri may enlist survey support from USACE, MoDOT, & MDNR. Guidelines would have to be adhered to using the GS manualbut all agencies are cooperators in this effort.Using these maps, an effort in the SW corner of Missouri may enlist survey support from USACE, MoDOT, & MDNR. Guidelines would have to be adhered to using the GS manualbut all agencies are cooperators in this effort.State advisors instrumental in providing some oversight and coordination with other potential effortsUSACE Geospatial has the Community of Practice meetings for geospatial collaboration

Documents

Height Modernization Coordination Meeting