2009 04 16 Indiana Kentucky Ohio CORS (spreadsheet.xls)
2008 02 11 Report on Use of Erla by NGS CORS Chief
2006 09 01 Special Sale: RTK dual-frequency GPS receivers
2006 02 21 Continuing Erla -- beyond a Decade of Service
2003 Oct 9 -- NTRIP technology, developed in Germany, was demonstrated successfully at NCAD with two varieties of GPS rover receivers, each receiving, via serial port, a stream of RTCM 2.2 messages, over the iNternet, from CORS Erla, enabling real-time corrected GPS positions. Real-time observations of the position results - 1 each second - was enabled by ESRI's Tracking Analyst extension on ArcView GIS 3.3. 95% of the points fell consistently within a 1" circle. The new technology enables serial output from the Ashtech Z12 CORS Erla Reference receiver to be packetized in TCP Internet Protocol and then available to any internet user (for example via cell phone) practically anywhere on Earth. The 2 rover receivers tested were: Trimble 4000sse and Spectra Precision 3220. Any GPS receiver supporting RTK is enabled for this positional capability. More information and to enjoy a test with your equipment, please contact us at firstname.lastname@example.org or 859 727-9999.
2003 Sep 12 00:50 The original choke ring antenna, Ashtech 700936D, was returned to operation with new state-of-art SCIGN dome. The LNA Low Noise Amplifier was replaced with new. The original LNA was repaired and is retained for backup.
In 1995 June, the Department of Defense completed the deployment of 24 satellites, each orbiting the Earth twice per day, transmitting signals that are sensed by GPS receivers on Earth. Processing multiple satellite transmissions simultaneously, the GPS receiver (a special purpose computer) can compute the location of its antenna to an accuracy approaching 1cm. Thus, GPS is increasingly being discovered as the best tool for positioning by increasingly wide categories of users.
The NCAD focus as Application Engineers, is to facilitate the utilization of GPS by Surveyors and GIS managers. Below are several documents providing background and guidance in considering your use of GPS.
Erla is a northern Kentucky CORS, provided by NCAD. More information about Erla is provided below. Since 1996, 5s data availability is nearly continuous and complete. This is not always reflected at NGS where the data is aggregated for public dissemination with data from other CORS. Gaps on the NGS server are likely due to imperfections in the process for downloading data by NGS from the NCAD ftp server. Please let us know if you can not get the data you want.
NCAD also provides historical 5s data and, by pre-arrangement, faster data, upto 2Hz. Please let us know what you would like. Thank you for using Erla.
2003 Sep 04 - New programs of GPS: WAAS, LAAS, VRS, NRT, Ntrip... Here is a fruitful link on the former http://gps.faa.gov. Stay tuned for more on the latter.
2003 Aug 21 The CORS Erla choke ring antenna, providing continuous service since 1996, died between 5 and 8am. Beginning 19:00 EST 2003 Aug 21, the temporary replacement antenna is the Spectra Precision Geodetic L1/L2 Ground Plane Model 571212238 s/n 31410509. Calibration details are at http://www.ngs.noaa.gov/ANTCAL.
2003 July 23 Why is Erla so stable?
2003 Apr 07 Nationwide CORS value rating -- being updated this year 2006.
2001 Publication Article by john Schmidt in ArcNews 2001 Fall issue: this short article is to synchronize spatial technology globally.
2000 May Erla is cited by NGS Chief Geodesist, initially at the InterAgency GPS Board web, 2013:http://www.gps.gov/systems/gps/modernization/sa/data/, comparing before and after Selective Availability is turned off by President Clinton's Directive.
1998 Mar Press Release: Erla: most stable, nationwide
1997 Sep Erla for Professionals
1997 Feb Geodetic Surveying 1997 Message to the Professional Land Surveyors of Ohio
1997 Jan Press Release: Erla, Continuously Operating Reference Station (CORS)
1997 Jan Free GPS the rationale for CORS Erla
1996 Dec Summary, of the 1995 UNAVCO Report evaluating GPS receivers and antennae.