FGCS-FIXED REFERENCE STATION WORKGROUP

A. ACTIVITIES AT THE NGS

B. WHAT ARE THE ACTIVITIES OF OTHER AGENCIES?

C. WHAT ARE THE NEEDS OF THE FGCS?

REAL-TIME ACTIVITIES AT THE NGSI. OPERATE AN NTRIP CASTER (Fed. Owned/operated –

currently 6, soon 9)

II. DEVELOP AND PUBLISH GUIDELINES DESCRIBING BEST PRACTICES.(RTK Users draft, RTN Operators draft, etc.)

III. PARTICIPATE IN MEETINGS, FORUMS, WORKSHOPS, ETC., CONCERNING REAL-TIME NETWORKS. SEEK LEADERSHIP ROLES.(FIG, ESRI, ACSM, RTCM, etc.)

IV. RESEARCH PHENOMENA AFFECTING ACCURATE REAL-TIME POSITIONING. (HTDP, IDOP, GEOID08, etc.)

POSITIONING

GPS/GNSS POSITIONINGPASSIVE MONUMENTS ACTIVE STATIONS

STATICNGS 58/59 GUIDELINES RTNFGCS ACCURACY STDS. VRS MAC FKPMFTRS. SOFTWARE & DOCS. ½ COST OR DOUBLE WORK DONE

OPERATORS DRAFT GUIDELINES

≈ 75 IN USA, 200+ WORLDWIDE

REAL-TIMESINGLE BASE MONUMENTSCLOSEST BASE CORSNGS CLASSICAL USER GUIDELINES-DRAFT

I. NGS Real Time Stream TeamProduct Manager

Richard SnayOutreach and User Relations

Bill HenningPam Fromhertz

CORS Data StreamsCharlie SchwarzNeil WestonGiovanni Sella

IT TeamBruce SailerHong ChenSky Chaleff

Supporting New ProductsReal time - essential that CORS/NGS supports this activity.TO DO: compute ultra-rapid orbits, QC coordinates, provide data-streams. Currently CORS only supports 6 sites with limited data-streams

GNSS: add GLONASS and new GPS frequencies to online storage in 2008

OPUS-flavorsNOAA-sister productsSpace Weather Prediction Center

went operational in 2007GPS Met Program will go

operational in 2010Co-Ops coordinates for NWLON

GNSS sites

1200 + 400 TO BE ADDED IN 2008

MDSI

HNPT

NGS HEADQUARTERS

NGS TESTING SITES – CORS STATIONS HNPT, MDSI, VAGP, PRMI VAGP

NGS TESTING SITES –PRMI, VITH, VIKH

VITH

PRMI

VIKH

NGS TESTING SITES –BARH ON LINE SOON

BARH

COLLEGE OF THE ATLANTIC GIS LABORATORY

EPRT

CORB

WELCOME & LINKS PAGEhttp://www.ngs.noaa.gov/CORS-Proxy/NGSRealtimeGNSS/welcomeNGSNtrip.jsp

REGISTRATION PAGE

ngs.realtime.gnss@noaa.gov

DATA STREAM WEB PAGE

RTCM 3.0 MESSAGE TYPES FROM NGS CORS

NOT

II. RT POSITIONING GUIDELINES

-

GUIDELINES, SPECS, STANDARDS √ SINGLE-BASE USER – DRAFT OUT

RTN PLANNING & NETWORK DESIGN

RTN CONSTRUCTION/SITE EVALUATION

RTN ADMINISTRATIVE

RTN USER

RTN TEAM – ADVISORS AND PARTNERS

http://www.ngs.noaa.gov/WHY SINGLE-

BASE?-ACCOMMODATE LEGACY USERS- CLOSEST BASE NETWORKS-AREAS WITH NO CELL COVERAGE- PROJECT SITE APPLICATIONS, SUCH AS MACHINE CONTROL

WHY EMPIRICAL?

-PLETHORA OF VARIABLES-TIMELINESS-PORT TO RTN USERS-DYNAMIC NATURE OF RT POSITIONING

SOME RT FIELD CONSIDERATIONS - Multipath - Position Dilution of Precision (PDOP) - Baseline Root Mean Square (RMS) - Number of satellites - Elevation mask (or cut-off angle) - Base accuracy- datum level, local level - Base security - Redundancy, redundancy, redundancy - Part(s) Per Million Error (ppm) – iono, tropo models, orbit errors - Space weather- sunspot numbers, solar maximum - Geoid quality - Site calibrations (a.k.a. Localizations) - Bubble adjustment - Latency, update rate - Fixed and float solutions- Accuracy versus Precision- Signal to Noise Ratio (S/N or C/N0)- Float and Fixed Solutions- Carrier phase- Code phase- VHF/UHF radio communication- CDMA/SIM/Cellular TCP/IP communication- WGS 84 versus NAD 83, or other local datumslocal and national datums- GPS, GLONASS, Galileo, Compass Constellations

RT SINGLE-BASE ACCURACY CLASSES

NGS HOME WEB PAGE

ACADEMIC/SCIENTIFICSPATIAL REFERENCE CENTERSVARIOUS DOTSCOUNTYCITYGEODETIC SURVEYS (NC, SC)MANUFACTURERSVENDOR NETWORKSAGRICULTUREMA & PA NETWORKS

EXAMPLES OF RTN ADMINISTRATORS IN THE USA

RAPIDLYGROWING

REAL TIME NETWORKS (RTN)

• HOW ARE THEY ESTABLISHED? • HOW ARE THEIR COORDINATES

COMPUTED? ARE THEY CONSISTENT? • HOW IS THE NETWORK ADJUSTED? • HOW DOES THE RTN ALIGN TO THE NSRS? • CAN USERS USE ANY MANUFACTURERS’

EQUIPMENT IN THE RTN?• DO OVERLAPPING NETWORKS GIVE THE

SAME COORDINATES?• WHAT ARE THE FIELD ACCURACIES?

?

3. Develop standards, specifications, and guidelines for administrating RTN. This may include: a. Reference station siting and construction considerations. b. Policy to promote the use of open source, generic data formats such as RTCM via the use of the most current Networked Transport of RTCM via Internet Protocol (NTRIP) programs. d. Policy to encourage the RTN to support as many different GNSS hardware and firmware packages as possible. e. Guidelines to recommend methods to enable RTN results to be aligned with the NSRS. This may include methods to archive and quality check RTN data. f. Guidelines to recommend methods to determine accurate positional coordinates and velocities for RTN reference stations.

II. RTN GUIDELINES IN NGS POLICY STATEMENT

ftp://ftp.ngs.noaa.gov/dist/whenning/RTNteam/REVIEW/RTpolicy.June2008.doc

OPERATING A RTN- CHAPTER ONE DRAFTftp://ftp.ngs.noaa.gov/dist/whenning/RTNteam/REVIEW/

•#1 Include a subnetwork of the RTN into the National CORS network. This would be three stations If RTN has less than 30 stations, 10% of RTN with greater than 30 stations.

#2 Align all RTN reference stations coordinates to the CORS network at 2-cm horizontal and 4-cm vertical

#3 For each reference station in the RTN, use the Online Positioning User Service (OPUS) at http://www.ngs.noaa.gov/OPUS/ to test for the continued consistency of its adopted positional coordinatesand velocity on a daily basis, and revise the station’s adopted coordinates and/or velocity if the tests reveal a need to do so.

RTNguidelines.June08.doc

BAKERSFIELD2 CORS- SEASONAL N/S & VERTICAL MOVEMENT

2002 2003 2004 2005 2006 2007 2008

2002 2003 2004 2005 2006 2007 2008

2002 2003 2004 2005 2006 2007 2008

EXAMPLE OF WHY RTN REFERENCE STATIONS SHOULD BE MONITORED

≈ 6 MM / YEARENGLISH TURN CORS

SUBSIDENCE

IDOP WITH SCALE COULD CORRELATE TO ACCURACY

III.

IDOP VALUES – 4 CORS EXAMPLEBEST IDOP = 1 √ N

THEREFORE, WITH 9 CORS, THE IDOP AT THE CENTROID WOULD BE .33, WITH 4 CORS IT WOULD BE .5 AT THE CENTROID

ADDITION OF RMS OF DISTANCE TO

CORS CONTRIBUTING TO

THE SOLUTION GIVES FINAL

UNITLESS NUMBER

.87.87

.87 .87

.5

.6.7

.8

.8

.7

.6

“IDOP” WILL BE THE SUBJECT OF A FORTHCOMING PAPER BY DRS. RICHARD SNAY, TOM SOLER AND CHARLES SCHWARZ

OPUS-RS Accuracyfor 15-minute data sets

0

1

2

3

4

5

6

7

0 0.2 0.4 0.6 0.8 1

IDOP

Std.

Err

. (cm

)

East-West North-South Ellipsoid Height

ACTIVITIES IN OTHER AGENCIES?

WHAT GUIDANCE OR PRODUCTS ARE NEEDED?

WORKGROUP ISSUES

ftp://ftp.ngs.noaa.gov/dist/whenning/FGCS