# Presentation: 883917

## View on GPS and Galileo‘From across the Atlantic...’

- View on GPS and Galileo*‘From across the Atlantic...’*

- Ruth E. Neilan
- International GNSS Service (IGS) Central Bureau
- Jet Propulsion Laboratory/California Institute of Technology
- February 19-21, 2008

## PerspectiveGPS, Galileo -  “more better”

*‘**North American View’ not applicable to science*:
- Science is ‘continent-blind’
- GNSS applications for top-end science & technology in regional areas, must have a global construct, network, a global reference frame
- Improving Earth observing with GNSS can provide early warning for natural disasters and mitigate their effects:
- Tsunamis, sea level rise, earthquakes,climate change,...
- Real-time responses

*Early lessons with GPS show that in-depth GPS/GNSS studies in any region require a global infrastructure - this is the perspective that drove the development of an international federation - IGS. (CASA-Uno’88)*

**Notes:**
Global reference frame - GPS and GLONASS have this, improvements needed, Galileo needs and realizes this with GGRFP 

Combination of GNSSs is very powerful

GPS monitoring of Mt. Fji for earthquakes and occultation measurements

## “The International GNSS Service provides the highest-quality GNSS data, products, and services in support of the Earth observations and research, positioning, navigation and timing, the terrestrial reference frame, Earth rotation, and other applications that benefit society.”

- IGS Mission
*Science in service to society*

**Notes:**
2005, Int’l GPS service became the Int’l  GNSS Service, reflecting incorpration of GLONASS and plans for other future GNSS: Galileo

## The BasicsInternational GNSS Service

**The Basics*****International GNSS Service***

- Recognized as an *international scientific service*
- Advocates an ***open data*** policy, equal access* *
- Name change from GPS to GNSS in 2005 reflects including:
**GLONASS** and future planning for **Galileo, QZSS, Compass, ... **
- Highest accuracy GPS  & GLONASS satellite orbits available ***anywhere***
- -3-5 cm 3-d wrms GPS solutions
- ~10-20 cm GLONASS solutions
- mm-level station positions and velocities, since 1992 (map)
- Network of over 350+ stations precision geodetic receivers produce GPS data on a continuous basis
- ~ 35 also track GLONASS
- ~100 report hourly
- Real-time IGS network initiated,
- prospects of integrity monitoring, other products
*Still major gaps, esp. in developing countries - AFREF*

## Quick answers: What is the IGS?

- Over 350 permanent, geodetic GNSS stations operated by more than 100 worldwide agencies comprise the IGS network.

- Civilian, dual frequency receivers tracking L1, L2, P2, and C1 or P2, minimally contributing daily files of 30-sec samples. **Sub-network tracking new L2C**

## Quick answers: What is the IGS?

- Graph courtesy Analysis Coordinator G. Gendt, GFZ Potsdam

- Many earth science missions and measurements, and multidisciplinary applications, rely upon the openly-available IGS products such as ephemerides and coordinate time series.

- The IGS Central Bureau handles overall coordination and day-to-day management of the IGS, view must be global.

## GLONASS

- Network and
- Final Orbit Comparison
- 1.21.08

## GNSS Contributes to Monitoring the Earth:

***Global Geodetic Observing System -  GGOS***

- GNSS combines with other space geodetic techniques, VLBI, SLR, DORIS, InSAR

**Notes:**
GNSS densifies observations, extremely economical compared to the other, but necessary techniques. Everyone’s tool.

## IGS & International Committee on GNSS

- IGS:
- Demonstrates highly successful community model for cooperation on GNSS
- Engaged with the International Committee on GNSS
*Perspective:* Underscore the need for GNSS interoperability
- Inter-system communication, cooperation and transparency facilitate users take-up of new technologies; which
- Further evolve and improve GNSS applications - ***benefiting society and our changing planet***

## Contact Information

- Ms. Ruth E. Neilan
- International GNSS Service Central Bureau
- Jet Propulsion Laboratory/Caltech
- MS 238-540
- 4800 Oak Grove Drive, Pasadena, CA
- 91109-8099
- USA
- tel: 818-354-8330
- fax: 818-393-6686
- _[ruth.neilan@jpl.nasa.gov](mailto:ruth.neilan@jpl.nasa.gov)_
*Part of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National  Aeronautics and Space Administration.*

## Some Back-ups

## What IGS Brings

- Partnerships - Bi-lateral and Multi-lateral
- True sense of community
- Robust, highly leveraged and redundant network
- Improvements needed in developing countries and Africa - AFREF
- Data from global and dense regional networks that aspire to IGS standards matches global standards
- Combined precise & accurate analyses; products are *‘world class’*
- Calibration, validation, verification - the ‘go to’ for
- Ephemerides, clocks, predicts
- Tracking station coordinates and velocities -> Reference Frame
- Earth rotation: polar motion, rate, length of day
- Tropospheric delays
- Ionospheric TEC
- Time scale
- Signal monitoring: GPS, GLONASS, L2C, GIOVE (*Galileo*), interference, integrity - more potential here

## Slide 13