Nav aids

GPS jamming exercises 0600Z to 1000Z, 1200Z to 1600Z and 1700Z to 2000Z daily 14 thru 16 may in area bound…

Tyrrhenian Sea · HYDROLANT 1499/18

What this record establishes

Archived notice · 2018-05-16 21:00Z

This notice comes from the historical archive. Its archived status does not establish when or how the reported situation ended.

Source and dates
NGA MSI broadcast-warn JSON (archive, frozen 2024-05) · MRCC ROME 140633Z MAY 18.. Issued 2018-05-14 06:56Z. First collected 2026-08-17 13:38Z; last seen in collection 2026-08-17 15:46Z. Collection dates record ingestion, not a new incident or a fresh field observation.
Location covered
Tyrrhenian Sea. The map shows an area described by the warning; the listed coordinate is its representative center. Check the original wording for limits and qualifications.

Current notices and reporting history in the Tyrrhenian Sea →

Activity windows · 9 in this warning

opens (UTC)closes (UTC)locallength
2018-05-14 06:00Z2018-05-14 10:00Z—4 h
2018-05-14 12:00Z2018-05-14 16:00Z—4 h
2018-05-14 17:00Z2018-05-14 20:00Z—3 h
2018-05-15 06:00Z2018-05-15 10:00Z—4 h
2018-05-15 12:00Z2018-05-15 16:00Z—4 h
2018-05-15 17:00Z2018-05-15 20:00Z—3 h
2018-05-16 06:00Z2018-05-16 10:00Z—4 h
2018-05-16 12:00Z2018-05-16 16:00Z—4 h
… 1 more

Parsed from the warning text; outside these windows the area is normally not active, but the warning stays in force until cancelled.

issued
2018-05-14 06:56Z
status
Archived notice
self-cancels
2018-05-16 21:00Z
authority
MRCC ROME 140633Z MAY 18.
issued by
MRCC ROME
sea
Tyrrhenian Sea
position
39.459, 10.357
source
NGA MSI broadcast-warn JSON (archive, frozen 2024-05) · first seen 2026-08-17 13:38Z

Original warning text

TYRRHENIAN SEA.
SARDINIA.
DNC 08.
1. GPS JAMMING EXERCISES 0600Z TO 1000Z,
   1200Z TO 1600Z AND 1700Z TO 2000Z DAILY
   14 THRU 16 MAY IN AREA BOUND BY
   40-03-47N 009-36-33E, 40-03-35N 011-07-11E,
   38-51-23N 011-06-27E, 38-51-27N 009-35-34E.
2. CANCEL THIS MSG 162100Z MAY 18.

Reading this warning

DNC (Digital Nautical Chart)
A reference to one of the regions of NGA's Digital Nautical Chart, used to tell the reader which charts a warning affects.
GNSS / GPS
Satellite positioning — GPS and other systems — and the testing, jamming and interference that make it unreliable in an area.
Area bound by
Introduces a list of positions that are the corners of an area — the polygon the warning applies to.
Position (degrees and minutes)
How warnings write positions: degrees, a hyphen, then minutes, with N/S and E/W — 49-40.8N 003-43.8W.
CANCEL THIS MSG
The warning's own expiry: a line telling the reader when the message cancels itself.
Date-time group (DTG)
A compact UTC timestamp — day, hour and minute followed by Z — such as 201500Z for the 20th at 15:00 UTC.

All warning terms →

Collected reports in this area · aids-to-navigation notices

261 within 180 nm since 1997 · 0 in the last 12 months · 0 listed in force now

97
00
05
10
15
20
22

Counts include repeat notices about the same situation. NGA archive coverage ends 2024-05; live collection began 2026-08-17. The period between them is incomplete. An empty year is not evidence that no hazards occurred.

Month of issue in the collected archive

J
F
M
A
M
J
J
A
S
O
N
D

All available years combined. Uneven collection and repeat bulletins affect these counts; this chart does not measure the seasonality or probability of incidents.

Nearby notices listed in force · within 120 nm

No other collected notice is currently listed in force within this radius. This does not establish safe conditions.

Worldwide in the collected sources

138 aids-to-navigation notices listed in force · see all

Record snapshot 2026-10-01 10:13Z; source collection times vary.

Nav aids

Lights extinguished, buoys off station, RACON/NAVTEX outages. All current aids-to-navigation notices →

Not for navigation. This is a re-rendering of an official navigational warning for awareness; mariners must use official NAVAREA broadcasts and their national MSI service.