Overview• Mission Overview and Significance• History • Challenges• NGS 10-Year Plan• NGS Programs• Details on Programs and California Focus

Marti Ikehara, State Geodetic Advisor

Marti.ikehara@noaa.gov

916-227-7325

Detailed Topics• New datums from NGS in your future• Development of a RTN backbone for California• Passive monumentation—who will maintain?

– Legislative safeguards adequate?• Publication of GEOID09• CBL usage, program

Rationale for new Datums• Terminology

– Horizontal becomes GEOMETRIC– Vertical becomes GEOPOTENTIAL

• When? 2018, if GRAV-D program is complete• Why? But why?!

1. Primarily needed a better vertical datum for “vertical” data(geoid, ortho ht) not obtained by traditional leveling

Airborne gravity observations will be used to develop next geoid– Geodetic Data collection relies upon navigation (GNSS)

satellites orbiting around the mass center of the Earth– NAD83 reference frame/datum is not geocentric2. NAD83 is not defined to include vertical velocities– Earth is not stable in all directions; reference frame must

account for this to be as geodetically accurate as possible

X

Z

Y

Earth-Centered Earth-Fixed (ECEF)

Coordinate System

EarthMass Center

Conventional Terrestrial Pole 1984.0

Bureau International de l'Heure (BIH)now the IERS

Gre

enw

ich

Mer

idia

n-X-Y

-Z

X, Y, Z = 0

XA, YA,ZA

(not NAD83)

GRS 80 Ellipsoid

ELLIPSOIDS used in the US(More than 60 have been used around the world)

CLARKE 1866(1879 – 1986)

a = 6,378,206.4 m 1/f = 294.97869821

GEODETIC REFERENCE SYSTEM 1980 - (GRS 80)(1986 - Present)

a = 6,378,137 m 1/f = 298.257222101

WORLD GEODETIC SYSTEM 1984 - (WGS 84) a = 6,378,137 m 1/f = 298.257223563

BESSEL 1841(1848 – 1879)

a = 6,377,397.155 m 1/f = 299.1528128

Simplified Concept of NAD 83 vs. ITRF00 Datums

2.2 meters

NAD 83Origin

ITRF 00Origin

Earth’s

Surface

h83

h00

Identically shaped ellipsoids (GRS-80)a = 6,378,137.000 meters (semi-major axis)1/f = 298.25722210088 (flattening)

Types of GEODETIC DATUMS HORIZONTAL

2 D (Latitude and Longitude) (e.g. NAD 27, NAD 83 (1986))

VERTICAL 1 D (Height) (e.g. Orthometric: NGVD 29, NAVD 88; Local Tidal)

GEOMETRIC 3 D (Latitude, Longitude and Ellipsoid Height)

Fixed and Stable - Coordinates seldom change (e.g. NAD 83 (1991), NAD 83 (2007))

also4 D (Latitude, Longitude, Ellipsoid Height, Velocities) Coordinates change

with time (e.g. ITRF00, ITRF08)

H + Ht +VE+ VEt

2 + 2 + 1+ 1 ITRF00 (2002.00)

Evolution of Geodetic Datums: from NAD27/NGVD29 to NAD83/NAVD88 to ?/ ?H + V2 + 127, 29

H + V2 + 1

83(86), 88

H + VE + VO

2 + 1 + 183(92), 88

GPS

+VELOCITIES (time)

H + Ht + VE + VO

2 + 2 + 1+ 1 83(07)+HTDP, 88

+ GRAVITY(geoid model)

H + Ht +VE+ VEt2 + 2 + 1+ 1

GEOMETRIC(VE+G)[+VEt] + Gt

1 + 1GEOPOTENTIAL

International Earth Rotation and Reference System Service (IERS)

(http://www.iers.org)

The International Terrestrial Reference System (ITRS) constitutes a set of prescriptions and conventions together with the modeling required to define origin, scale, orientation and time evolution

ITRS is realized by the International Terrestrial Reference Frame (ITRF) based upon estimated coordinates and velocities of a set of stations observed by Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging ( SLR), Global Positioning System (GPS) and GLONASS (GNSS), and Doppler Orbitography and Radio-positioning Integrated by Satellite (DORIS).

ITRF89, ITRF90, ITRF91, ITRF92, ITRF93, ITRF94, ITRF95, ITRF96, ITRF97, ITRF2000, ITRF2005

International Global Navigation Satellite Systems Service (IGS)

International Laser Ranging Service (ILRS)

International Very Long Baseline Service (IVS)

International DORIS Service (IDS)

International Terrestrial Reference Frame4 Global Independent Positioning Technologies

Tectonic Horizontal Motions

Treatment of velocity in new datum

• ITRF has velocities relative to the COM• Big question for our new datum is how is

velocity treated: like ITRF OR “stable” North America like NAD83?

Horizontal Velocities, relative to NAD83 datumreflected in HTDP model

CORS Data allows for Monitoring Vertical Crustal Motion

Vertical velocities associated with Glacial Isostatic Adjustment (rebound)

Treatment of velocities in new datum• ITRF has velocities relative to the COM• Big question for our new datum is how is

velocity treated: like ITRF OR “stable” North America like NAD83?

• West Coast, esp CA, is accustomed to needing to account for velocity, at least horizontal

• How do we incorporate vertical velocity?• How often would we change Coordinates?

– ITRF: >1cm H, 2cm Eht; if ITRF changes, NAD83 too– Should it be 5mm, 10mm? At least annually??

NGS CORS, as of Feb, 2010: 108 in CA

Proposed Backbonefor a streaming RTN

• Total statewide=154• Funded, currently, by

various programs=76• Funded needed=78• Partners being sought

– $15,000 or $150,000• Data streams

– Regular: 20– Sustaining: Unlimited

• Not network solution

Elements of CRTNCA Real Time Network

• Currently, single base positioning available free• How do you get it? Contact Yehuda Bock, CSRC• Goal: RT data streaming to partners• Partners could be public agencies, private

providers of RTN service• Funds needed to establish telemetry at 78 sites• Operational partners: MWD, USGS, SOPAC,

Counties: LA, Orange, SD, and UNAVCO PBO

Current status:

http://sopac.ucsd.edu/projects/realtime

NGS and RTNs

• Draft RTN Guidelines indicate that RTN providers should incorporate some CORS (10%, minimum of 3) into their network

• Doing so will enable connection with the NSRS or CSRS in the case of CRTN

• NGS may ‘certify’ RTN providers, after reviewing practices, adjustment, etc

• NGS long-term goal is to have national backbone of RT CORS that we operate

• Maintenance of passive monuments is nil/low

Passive monumentation

• MAINTENANCE?• In LS Act, protected along

R/W, transportation• Not protected

on privateproperty

• Only actionsby surveyors

http://www.dca.ca.gov/pels/pls_act.pdf

PROFESSIONAL LAND SURVEYORS’ ACT(Business and Professions Code §§ 8700 – 8805)

INCLUDES AMENDMENTS MADE DURING THE 2007 LEGISLATIVE SESSION

(Effective January 1, 2008, unless otherwise noted)CHAPTER 15. LAND SURVEYORS

pg 20 of 31:

NOTE, in (b): When monuments exist that "...provide horizontal or vertical survey control,"

8771. Record of survey - monumentation

• (a) Monuments set shall be sufficient in number and durability and efficiently placed so as not to be readily disturbed, to assure, together with monuments already existing, the perpetuation or facile reestablishment of any point or line of the survey.

• (b) When monuments exist that control the location of subdivisions, tracts, boundaries, roads, streets, or highways, or provide horizontal or vertical survey control, the monuments shall be located and referenced by or under the direction of a licensed land surveyor or registered civil engineer prior to the time when any streets, highways, other rights-of-way, or easements are improved, constructed, reconstructed, maintained, resurfaced, or relocated, and a corner record or record of survey of the references shall be filed with the county surveyor. They shall be reset in the surface of the new construction, a suitable monument box placed thereon, or permanent witness monuments set to perpetuate their location if any monument could be destroyed, damaged, covered, or otherwise obliterated, and a corner record or record of survey filed with the county surveyor prior to the recording of a certificate of completion for the project.

Questions from reading PLS Act• If it’s on a superceded datum or has VERTCON

elevations, does the monument still “provide” control? Or did it “used to provide” control?

• Should monuments on private property or on public property that is NOT a road easement also be protected?

• Do they need to be replaced or ‘merely’ referenced to something local?

• This pertains to practice of licensed surveyors; there are many others capable of destruction

GEOID09 published in Sept 09

• In California, GEOID03 considered 567 bench marks with GPS data (ellipsoid heights), and kept 549

• In GEOID09, there were 833 considered; 747 were included, a 36% increase

GEOID09 compared to GEOID0309: teal, good; yellow: State advisor-rejected;red: analysis-rejected

03 (underlying dots): dk blue, kept; orange: rejected

From Helmer’s article in Winter 09/10 issue of California Surveyor

Calibration Base Lines

Possible CBLs to be measured1. Briggsmore, Modesto: not done by NGS2. Concord: usage shows discrepancy of 1cm3. Camarillo: last monument knocked out4. Sacramento: monuments about to be set

Need to hear interest/POC for: 5. Inyokern: last measured in 1990!6. Reno: re-measurement

CBL Usage, Maintenance

• Who has used one in the past 3 years?• Why? or Why not?

– Distance from nearest one?– Bothersome to get key?– Usage procedures?

• Forms needed for usage, filing with host?• Other issues??

http://www.dot.ca.gov/hq/row/landsurveys/geodetic/geodetic_control.html

Kml’s and shapefiles downloadable

5 data types available/possible: HVL, H, CORS, VL and HVHM

Using NGS DSWORLD software and Google earth to get the latest

geodetic data for your project

Start by downloading “Google earth” at: http://earth.google.com/download-earth.html

Click here

Mouse-over the “TOOLS” button

Click on “DOWNLOAD

PC SOFTWARE”

Open the NGS main page at www.ngs.noaa.govMouse over the “Tools” button and then click on the

“Download PC Software” link.

Click here

Next, click on the link: “User Contributed Software is also available…..”

Next, click on the DSWORLD (Version *.**) link. A “file

download” window will appear. Choose to save the file where you can easily find it. It will be a zip file, so you will need to

unzip it and then double click on the setup.exe file. That will install the program for you.

For additional information or assistance, please contact your NGS State Geodetic Advisor

Anything Else?!

• Marti.ikehara@noaa.gov• 916-227-7325

If you thinkof something:

• ftp://ftp.ngs.noaa.gov/pub/marti