# Presentation: 891754

## NGS SUPPORT FOR REAL-TIME POSITIONING

*2008 CORS USERS FORUM*
*CGSIC - SAVANNAH, GA*
*SEPTEMBER 16, 2008*

*Bill Henning, Senior Geodesist, PLS.*

##  Ensure that geodetic issues are adequately addressed in operation and use of real-time positioning systems

-  Ensure that geodetic issues are adequately addressed in operation and use of real-time positioning systems

_*OVERALL PROGRAM OBJECTIVE*_

**APPLICATION: TO ENSURE THE PROPER GEODETIC BASIS FOR **_***ACCURATE RT POSITIONING ALIGNED TO THE NSRS***_

**Notes:**
This is the single message of this presentation.

Real time positioning systems will happen and are already happening whether NGS plays a role or not.

Compare to GIS experience

This is not just a matter of providing data. There is also a strong education component.

## The National Geodetic Survey 10 Year PlanMission, Vision and Strategy 2008-2018

**The National Geodetic Survey 10 Year Plan****Mission, Vision and Strategy ****2008-2018**

**http://www.ngs.noaa.gov/INFO/tenyearfinal.shtml**

**http://www.ngs.noaa.gov/INFO/StrategicPlan_20080810.pdf**

## GPS/GNSS POSITIONING

**GPS/GNSS POSITIONING**

_**PASSIVE MONUMENTS**_**	****                     **_**ACTIVE STATIONS**_
**	****	****	****   **_** **__**STATIC**_
**	****	**_*NGS 58/59 GUIDELINES*_		        _**RTN**_
- 		FGDC ACCURACY STDS.                 _VRS    MAC     FKP_
- 		MFTRS. SOFTWARE & DOCS.**     **1⁄2 COST OR** **DOUBLE WORK DONE
**	****	****	****	****	****         **OPERATORS DRAFT** **GUIDELINES
**	****	****	****    ****	****	****      **≈ 75 IN USA, 200+WORLDWIDE
- 				                                     “_***OPERATING AN RTN–***_
- 							_***CHAP. 1” DRAFT***_
**	****	****	****     **_**REAL-TIME**_
- 			SINGLE BASE MONUMENTS
- 			CLOSEST BASE CORS
- 			_*NGS CLASSICAL USER GUIDELINES-DRAFT*_

## REAL-TIME ACTIVITIES AT THE NGS

**    ****OPERATE AN NTRIP CASTER. ****(Fed. Owned/operated – currently 7 -  soon 9. RTCM 2.3 & 3.x, From Foundation CORS. NO CORRECTORS)**
**    ****DEVELOP AND PUBLISH GUIDELINES DESCRIBING BEST PRACTICES IN RTK & RTN .****(RTK Users draft, RTN Operators draft, etc.)**
**  ****PARTICIPATE IN MEETINGS, FORUMS, WORKSHOPS, ETC., CONCERNING REAL-TIME NETWORKS. SEEK LEADERSHIP ROLES.****(FIG, FGCS, ESRI, ACSM, RTCM, etc.)**
**  ****RESEARCH PHENOMENA AFFECTING ACCURATE REAL-TIME POSITIONING. ****(Orbits, refraction, multipath, antenna calibration, and crustal motion.**

## NGS SUPPORT FOR REAL-TIME POSITIONINGWHAT’S HAPPENED THE LAST YEAR?

- APPROVED NGS POLICY
- STREAMING RTCM 2.3 & 3.0 DATA VIA NTRIP – 7 CORS
- DRAFT USER GUIDELINES FOR CLASSICAL RT POSITIONING RELEASED
- DRAFT RTN OPERATORS GUIDELINES IN-HOUSE VETTING
- FIG COLLABORATION ON INTERNATIONAL GUIDELINES
- NGS= ANALYSIS CENTER FOR IGS ORBITS
- RTN TEAMS FORMED – WORKGROUPS, FGCS
- REAL-TIME NGS WEB SITE IN PRODUCTION
- RELEASED HTDP 3.0
- “IDOP” INTRODUCED
- 20 WORKSHOPS (ESRI, ACSM, FIG, STATES, ETC. )

## I. NGS Real Time Stream Team

- I. _*NGS Real Time Stream Team*_

- Product Manager
- 	Richard Snay
- Outreach and User Relations
- 	Bill Henning
- 	Pam Fromhertz
- CORS Data Streams
- 	Charlie Schwarz
- 	Neil Weston
- 	Giovanni Sella
- IT / Software Development Team
- 	Bruce  Sailer
- 	Hong Chen
- 	Sky Chaleff

**mailto:ngs.realtime.gnss@noaa.gov**

**Notes:**
These are the people who have participated in the development of the NGS real time broadcaster and are expected to continue as it becomes an operational prototype.

## NGS HEADQUARTERS

**MDSI**

**HNPT**

**NGS HEADQUARTERS**

**NGS TESTING SITES – CORS STATIONS HNPT, MDSI, VAGP, VITH,PRMI, BARH**
**ON LINE SOON = ESPT, CORB**

**VAGP**

## DAILY REPORTS

- 01. MOUNT: /HNPT Total Time Available: 1439min 56sec Availability Percentage: 100.00% Unique Users: 4 (bemerson, sbruce, ujeremy, wgeorg)
-  02. MOUNT: /HNPT1 Total Time Available: 1439min 56sec Availability Percentage: 100.00% Unique Users: 1 (sbruce)
-  03. MOUNT: /MDSI Total Time Available: 1439min 56sec Availability Percentage: 100.00% Unique Users: 2 (bemerson, sbruce)
-  04. MOUNT: /MDSI1 Total Time Available: 1439min 56sec Availability Percentage: 100.00% Unique Users: 3 (mchris, sbruce, ujeremy)
- 05. MOUNT: /PRMI Total Time Available: 1439min 46sec Availability Percentage: 99.99% Unique Users: 2 (rcarlos, sbruce) 06.
-  MOUNT: /VAGP Total Time Available: 1439min 56sec Availability Percentage: 100.00% Unique Users: 3 (bemerson, sbruce, ujeremy)
- 07. MOUNT: /VIKH Total Time Available: 1438min 35sec Availability Percentage: 99.91% Unique Users: 2 (rcarlos, sbruce) 08. MOUNT: /VITH Total Time Available: 1438min 05sec Availability Percentage: 99.86% Unique Users: 2 (rcarlos, sbruce)** **

**USER ACCESS SUMMARY ----------------------------------------------------- **
***simultaneous connections to a single mountpoint were used by the user. **
**USER: bemerson **
**	****Mount Logins Time Connected**
**	**** ****----- ------ --------------**
**	**** ****/HNPT 2 2879 min 45 sec***
**	**** ****/MDSI 3 4319 min 26 sec***
**	**** ****/VAGP 2 2879 min 37 sec* **
**02. USER: mchris**
**	**** ****Mount Logins Time Connected **
**	**** ****----- ------ --------------**
**	**** ****/MDSI1 1 1437 min 45 sec **
**03. USER: rcarlos **
**	****Mount Logins Time Connected**
**	**** ****----- ------ -------------- **
**	****/PRMI 14 1439 min 00 sec* **
**	****/VIKH 12 1438 min 47 sec***
**	**** ****/VITH 9 1437 min 34 sec***
** ****04. USER: sbruce **
**	****Mount Logins Time Connected**
**	**** ****----- ------ --------------**
**	**** ****/HNPT 1440 45 min 42 sec**
**	**** ****/HNPT1 1440 18 min 13 sec**
**	**** ****/MDSI 1440 47 min 25 sec**
**	**** ****/MDSI1 1440 19 min 55 sec**
**	**** ****/PRMI 1440 56 min 10 sec**
**	**** ****/VAGP 1439 47 min 11 sec**
**	**** ****/VIKH 1438 51 min 31 sec**
**	**** ****/VITH 1436 63 min 45 sec**
** ****05. USER: ujeremy**
**	**** ****Mount Logins Time Connected**
**	**** ****----- ------ --------------**
**	**** ****/HNPT 2 1439 min 55 sec**
**	**** ****/MDSI1 3 1439 min 53 sec**
**	**** ****/VAGP 2 1439 min 58 sec***
** ****06. USER: wgeorg**
**	**** ****Mount Logins Time Connected**
**	**** ****----- ------ --------------**
**	**** ****/HNPT 1 1439 min 24 sec **
**UNAUTHORIZED ACCESS ATTEMPTS ----------------------------------------------------- *** NO UNAUTHORIZED ACCESS ATTEMPTS TO REPORT *** **

**DAILY REPORTS**

## NGS WEB PAGES – CURRENTLY TEST/BETA

## II. THE TWO DIRECTIONS OF REAL-TIME NETWORK POSITIONING

- TOP DOWN: _Overall Administrator’s viewpoint-_ Alignment to the NSRS, coordinates, adjustments, Network spacing, Site requirements, Communication issues, Personnel, Cost/Benefit analysis, $$$$, Partners
- USER UP:  _Best methods-_ Field techniques, GNSS knowledge, Knowing datum requirements, Knowing accuracy requirements, Calibrations, Applications, Data management

- RTN

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

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

- _[http://www.ngs.noaa.gov/](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**

***RT ISSUES – ***
***SUCH AS:***
** ****PDOP**
** ****RMS**
** ****# SVNS**
** ****BASELINE LENGTH**
** ****REDUNDANCY**
** ****# BASES**
** ****OBS TIMES**
** ****EQUIPMENT**
** ****LATENCY**
** ****FIXED/FLOAT **
** ****ELEVATION MASK**
** ****LOCALIZATIONS**
**ACCURACY/PRECISION**
** ****SPACE WEATHER**
** ****GEOID QUALITY**
** ****QA / QC**
**GPS / GLONASS**

## NGS HOME PAGE

- _[http://](http://www.ngs.noaa.gov/)__[www.ngs.noaa.gov](http://www.ngs.noaa.gov/)__[/](http://www.ngs.noaa.gov/)_

## REAL TIME NETWORKS (RTN)

**PERHAPS OVER 75 RTN EXIST IN THE USA WITH MANY IN THE PLANNING STAGES**
**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?**

**?**

## REAL-TIME CONSIDERATIONS

**PASSIVE / ACTIVE**** **
**DATUMS & ADJUSTMENT EPOCHS**
**GEOID + ELLIPSOID / CALIBRATE**** **
**SINGLE BASE / RTN**** **
**GNSS / GPS**
**GRID / GROUND**

## Guidelines for Operating a Real-Time GNSS NetworkCHAPTER ONE -Achieving Consistency Among Positional Coordinates and Velocities 

**Guidelines for Operating a Real-Time GNSS Network****CHAPTER ONE -Achieving Consistency Among Positional Coordinates and Velocities **

- ITRF 2000 or NAD 833 recommendations:
- #1 Include a subnetwork of the RTN into the National CORS network.
- #2 For each reference station contained in the RTN, adopt values for its 3-dimensional positional coordinates (at a selected epoch date) and a velocity that are consistent with corresponding values adopted by NGS for reference stations in the National CORS network.
- #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 coordinates and velocity on a daily basis, and revise the station’s adopted coordinates and/or velocity if the tests reveal a need to do so.

## III. OUTREACH, COOPERATIVE EFFORTS AND LEADERSHIP

***FGCS***

***TSRC***

**LSRC**

**+ PUBLIC & PRIVATE *****RTN ADMINISTRATORS***** SPANNING MORE THAN 35 STATES**

## IV.  HTDP 3.0- REFERENCE STATION VELOCITIES

## “IDOP” – CAN BE APPLIED TO RTN

**“****IDOP”**** – CAN BE APPLIED TO RTN**

**IDOP + SCALE WILL CORRELATE TO ACCURACY**

## IDOP VALUES – 4 CORS EXAMPLE

**BEST 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 Accuracy
- for 15-minute data sets

## NGS RT CONTACTS (HEADQUARTERS)

- _[RICHARD.SNAY@NOAA.GOV](mailto:RICHARD.SNAY@NOAA.GOV)__ REAL-TIME POSITIONING PROJECT LEAD__ _
- _[GIOVANNI.SELLA@NOAA.GOV](mailto:GIOVANNI.SELLA@NOAA.GOV)__ NATIONAL CORS DIRECTOR__ _
- _[WILLIAM.HENNING@NOAA.GOV](mailto:WILLIAM.HENNING@NOAA.GOV)__  __REAL-TIME POSITIONING- COORDINATION & OUTREACH_