GPS spoofing off Long Beach during a military test window

30 January 2026 · Military test · Last updated 10 November 2026

Ships approaching Long Beach reported GNSS outages and position jumps on the night of 29 January 2026. The Coast Guard named a GPS test as the likely cause.

Local time: 23:00–00:00 PST (UTC−8), night of 29–30 Jan

Source: GPSInterference.com, https://gpsinterference.com/reports/2026-01-30-long-beach-spoofing-gps-test-window. Free to reuse with this credit and a link.

The Port of Long Beach, California, from the air
The Port of Long Beach, California, from the air · Photo: Northwalker · CC0

What happened

Ships approaching Long Beach reported GNSS outages to the Los Angeles/Long Beach Vessel Traffic Service between 23:00 and midnight local time on 29 January 2026 (07:00–08:00 UTC on 30 January).[1][2]

AIS data from at least 7 vessels showed position jumps that the authors of an Inside GNSS analysis describe as indicative of spoofing, across an area more than 100 miles wide.[1]

Minutes of the local Harbor Safety Committee say Coast Guard personnel identified a GPS testing event as the likely cause.[1][2]

The authors name a Point Mugu Sea Range test, PMSRCA GPS 26-02, scheduled daily from 07:00 to 14:00 UTC on 27 January to 31 January, as the most likely source, while saying the data does not provide certainty.[1][3]

What our map showed

Our map shows aircraft reporting low GPS position accuracy. It does not show who or what caused it. A day is a full UTC day, so short events can be diluted.

Spoofed aircraft can broadcast confident but wrong positions, so spoofing doesn't always lower reported accuracy.

Ships use AIS, not ADS-B, so our map shows aircraft over the same waters, not the ships themselves.

Open this day on the live map

Affected share
33%
High-interference hexagons
15 of 45
30-day average
28%
About the same as the previous 30 days

By altitude

AltitudeMeasured hexagonsHighShare30-day average
below 5,000 ft312065%53%
5,000–15,000 ft34618%10%
15,000–30,000 ft4300%1%
above 30,000 ft4000%0%

Each day checked

Day (UTC)Measured hexagonsHighShare
29 January 2026451533%
30 January 2026451431%

Day by day

Affected share by day, 23 January 2026 to 2 February 2026 Share of measured hexagons with high interference in the area, for each UTC day. The dashed line is the average of the 30 days before the event. Gaps are days without data. 40% 0% 23 January 2026 2 February 2026
Day checked · 30-day average
Affected share by day, 23 January 2026 to 2 February 2026
Day (UTC)Share
23 January 202636%
24 January 202640%
25 January 202633%
26 January 202631%
27 January 202633%
28 January 202633%
29 January 202633%
30 January 202631%
31 January 202629%
1 February 202629%
2 February 202630%

What others said

Context

Sources

  1. Inside GNSS, Captain James Haley and Captain Dana A. Goward. LA/Long Beach VTIS Records Spoofing Event in January 2026 GPS Test Window, 10 June 2026.
  2. gCaptain, Capt. James Haley and Dana A. Goward. GPS Interference Off California Offers Warning for Global Shipping, 1 July 2026.
  3. FAA Safety Team. Notice NOTC4801: GPS Interference Testing at Point Mugu, CA 27 JAN - 02 FEB, 22 January 2026.

Cite this report

GPSInterference.com (2026). GPS spoofing off Long Beach during a military test window. Report, 10 November 2026, updated 10 November 2026. https://gpsinterference.com/reports/2026-01-30-long-beach-spoofing-gps-test-window. Data: adsb.lol ADS-B, method v2.
BibTeX
@misc{gpsinterference_2026_01_30_long_beach_spoofing_gps_test_window,
  author = {{GPSInterference.com}},
  title = {GPS spoofing off Long Beach during a military test window},
  year = {2026},
  howpublished = {\url{https://gpsinterference.com/reports/2026-01-30-long-beach-spoofing-gps-test-window}},
  note = {Report, updated 2026-11-10. Data: adsb.lol ADS-B, method v2}
}