NCGS

Geodetic News

Users of the NCGS Geodetic Control Database (https://ncgs.nc.gov/geodeticmonuments) may notice some intermittent outages. NCGS is aware of the issue and is working to resolve it as quickly as possible.

In the meantime, users may want to try accessing the database via a different browser, and/or users may try a hard refresh to force the browser to fully reload the database page. On most browsers a hard refresh can be accomlished by pressing CTRL+F5, but users should consult their browser help resources for exact instructions. Neither of these solutions are a guaranteed fix, but they have resolved the issue in some cases.

The Federal Aviation Administration (FAA) has issued the following notice of GPS interference testing that may result in unreliable or unavailable GPS signal:

FLIGHT ADVISORY: GPS Interference Testing
NAVY WARFARE DEVELOPMENT CENTER (NWDC) 20-01 (Revision 1)
07 – 10 August 2020 / Portsmouth, VA

This test will be centered at 36.950000°, -76.308333° and extend outward and upward like a bowl affecting the GPS signal 49 nautical miles (NM) away at 50 ft above ground elevation (AGL) relative to the center point’s (CP’s) ground elevation (~7 ft MSL) plus the height of the antenna, 107 NM away at 4,000 ft AGL, and so on. The tests will be conducted daily 2130 Z - 2300 Z (5:30 PM - 7:00 PM EDT).

The FAA does not provide an affected radius figure of interest to remote pilots for 400 ft AGL. Based on the notice’s data, NCGS estimates this radius to be 60 NM. Since this radius is relative to the CP’s ground elevation, the radius needs to be extended by 5 NM for UAV operations at higher ground elevations where the combined ground elevation difference (remote site elevation – CP elevation) + UAV flight elevation approaches or exceeds 601 ft, 10 NM for 844 ft, 15 NM for 1,129 ft, and 20 NM for 1,456 ft. NCGS recommends adding a wide buffer (>10 NM) to any radius figure for operations near 400 ft AGL.

As of today, June 1, 2020, the VRS_CMRx and VRS_RTCM32 mountpoints have been configured to include the Galileo and BeiDou satellite data into the correction solution to NC RTN users. CMRx and RTCM 3.2 are the only versions of the output formats the NC RTN has available for the mountpoints that support the Galileo and BeiDou satellite data. The other mountpoints (VRS_CMRp, VRS_RTCM23, VRS_RTCM3) will still include only the GPS and GLONASS satellite data in the solution. Although the VRS_CMRx and VRS_RTCM32 mountpoints are now configured to include the Galileo and BeiDou satellite data, users may not receive any BeiDou satellite correction data because the NC RTN application can’t process the data from the latest BeiDou satellites (BeiDou-3) yet.

The NC Geodetic Survey website has undergone some recent back-end changes to enhance security and functionality. If you have not already done so, please update your bookmark for the NCGS page to the URL below.

Geodetic News Archive

Geodetic news items older than approximately 6 months (unless deemed critical) as well as expired GPS interference testing notices can be found on the news archive page at the link below.

Real Time Network Sensor Map

To view the real time network sensor map please visit the link below.