# Presentation: 760007

## ENHANCING CORS  

- Richard Snay
- NGS Convocation
- Silver Spring, MD
- October 24, 2005

## Continuously Operating Reference Stations

***Continuously Operating Reference Stations***

## CORS OVERVIEW

- National CORS Network contains 688 sites
- Cooperative CORS Network contains 140 sites
- California CORS Network contains 350+ sites
- Combined CORS Network growing at rate of 15 sites per month
- More than 155 organizations participate in the CORS program
- Provides code range (C/A, P1, P2)
- and carrier phase observations (L1, L2)

## CORS APPLICATIONS

- Postmission Static Positioning (cm-level accuracy with a few hours of data, dm-level accuracy with one minute of data)
- Postmission Kinematic Positioning (dm-level accuracy for an aircraft, boat, or land vehicle)
- Geophysics / Crustal Motion
- Meteorology / Water Vapor in Atmosphere
- Space Weather / Free Electrons in Ionosphere

## CORS NETWORK NOW CONTAINS 6 IRAQI SITES

***Established by ***
***U.S. Army***

- Several CORS collected 1-second GPS data following Hurricanes Katrina and Rita to support airborne mapping of the recovery zones.

## CORS ACCOMPLISHMENTS in FISCAL YEAR 2005

- Combined CORS network grew by more than 240 sites. (Thanks mainly to EarthScope’s Plate Boundary Observatory and to RTK networks being established by state and local governments.)
- NOAA now using CORS data to nowcast Total Electron Content (TEC) over CONUS every 15 minutes.
- NOAA now using CORS data operationally to nowcast precipitable water vapor over CONUS every hour.
- Accuracy of NGS-produced orbits improved by 37.5%         (4 cm  2.5 cm).

## CORS Accomplishments in Fiscal Year 2005 (continued)

- NOAA now validates positional coordinates of Cooperative CORS sites daily (previously it was done monthly).
- The Online Positioning User Service (OPUS) processed 150,000 GPS data sets.
- The ‘User-Friendly’ CORS (UFCORS) utility delivered its 2-millionth GPS data package.  UFCORS is now delivering an average of 2,000 data packages per day.
- CORS Web site now featuring new regional maps and employing Google-provided imagery.

## ON THE CORS HORIZON

**Within the next 2 months**
- 	* 15 Mexican sites will join the CORS network.
- 	* OPUS-DB (database) will allow users to archive their results in the National Geodetic Survey’s database.
- 	* NOAA will release new guidelines for establishing CORS
-            sites and managing CORS information.

## NEW CORS GUIDELINES

**GOALS**:
- Improve quality of CORS data
- Focus attention on CORS meta-data requirements

**Selected Items**:
-    * Site Selection Team established to evaluate new sites more
-       rigorously before including them into the CORS network
-    * Encourage more stable sites
-    * Avoid multipath-prone sites
-    * Radomes not recommended except ...
-    * Track all satellites regardless of their health status
-    * Track satellites to lower elevation angles
-    * Provide suite of photos for each site

## ONGOING CORS RESEARCH

- 	* Exploring the use of NTRIP to stream GPS data from selected CORS via the Internet.
- 	* Developing OPUS-RS (rapid static) that will enable users to obtain positional coordinates with cm-level accuracy using only 15 minutes of data