NCGS

Geodetic News

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
MARINE CORPS SPECIAL OPERATIONS COMMAND (MARSOC) 21-01 REVISION 2
1 – 21 March 2021 / Camp Lejeune, NC

This test will be centered at 34.527500°, -77.542778° and extend outward and upward like a bowl affecting the GPS signal 21 Nautical miles (NM) away at 50 ft Above Ground Elevation (AGL) relative to the center point’s (CP’s) ground elevation (~60 ft MSL), 80 NM away at 4,000 ft AGL, and so on. The specific time period that these tests will be conducted is posted on the announcement with the following caveat: “Each event may last the entire requested period.”

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 52 NM. Since this radius is relative to the CP’s ground elevation (~60 ft), 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 540 ft, 10 NM for 730 ft, 15 NM for 980 ft, and 20 NM for 1,320 ft. NCGS recommends adding a wide buffer (>10 NM) to any radius figure for operations near 400 ft AGL.

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
CARRIER STRIKE GROUP FOUR (CSG4) 21-03 REVISION 1
CARRIER STRIKE GROUP FOUR (CSG4) 21-04
1 – 14 March 2021 / Off-The-Coast

These tests will be centered at 32.166667°, -79.666667°, which is 48 NM SSE of the CHARLESTON VORTAC (CHS) in Charleston, SC. There will be two tests each day, a narrow range test followed by a wide range test:

Date: 1 March
Narrow range test: 10:30 am EST - 11:14 am EST
Wide range test: 11:15 am EST - 12:59 pm EST

Date: 11 March
Narrow range test: 6:30 am EST - 7:14 am EST
Wide range test: 7:15 am EST - 12:30 pm EST

Date: 14 March
Narrow range test: 11:30 am EDT - 12:14 pm EDT
Wide range test: 12:15 pm EDT - 5:30 pm EDT

Please note the following caveat: “Each event may last the entire requested period.”

The narrow range test will extend outward and upward like a vase affecting the GPS signal 46 NM at 50 ft Above Ground Elevation (AGL) relative to the center point’s (CP’s) ground elevation (0 ft MSL), 109 NM away at 4,000 ft AGL, and 149 NM at 40,000 Mean Sea Level (MSL).

The broad range test will extend outward and upward like a bowl affecting the GPS signal 71 NM at 50 ft AGL relative to the center point’s (CP’s) ground elevation (0 ft MSL), 134 NM at 4,000 ft AGL, 178 NM at 10,000 ft MSL, and so on.

The FAA does not provide an affected radius figure of interest to remote pilots for 400 ft AGL. Based on each notice’s data, NCGS estimates this radius to be 72 NM for the narrow range test and 83 NM for the wide range test.

Since these radius figures are relative to the CP’s ground elevation (0 ft MSL), the radius needs to be extended by the following distances for UAV operations at higher ground elevations where the combined ground elevation difference (remote site elevation – CP elevation) + UAV flight elevation approaches or exceeds:

Narrow range test (72 NM at 400 ft AGL)
• 5 NM for 560 ft
• 10 NM for 780 ft
• 15 NM for 1,060 ft
• 20 NM for 1,410 ft

NCGS recommends adding a wide buffer (>10 NM) to any radius figure for UAV 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.