GPS Satellite Outages

GPS satellite outages are determined by the US Air Force using a Notice Advisory to Navstar Users (NANU). NANUs are categorized by their type and can represent forecasted, current or summary outages. See the full list of outage types on the CelesTrak website.

Current Time

Current Outages

GPS satellite outages identified as current by the US Air Force. Current outage types are usually reserved for unscheduled outages.

There are no current outages at this time.

Predicted Outages

GPS satellite outages identified as predicted by the US Air Force.

There are no predicted outages at this time.

Recent Outages

GPS satellite outages identified as historical by the US Air Force, occurring within the last month.

PRNSVNNANUTypeOutage startOutage stopDuration
20512019114FCSTSUMMJul 23, 2019 23:25:00Jul 24, 2019 05:14:0000d:05h:49m:000s
8722019115FCSTSUMMJul 24, 2019 15:26:00Jul 24, 2019 18:59:0000d:03h:33m:000s
18342019116UNUNOREFJul 25, 2019 15:40:00Jul 25, 2019 15:41:0000d:00h:01m:000s
18342019120UNUNOREFJul 26, 2019 15:32:00Jul 26, 2019 15:33:0000d:00h:01m:000s
26712019121FCSTSUMMJul 26, 2019 12:52:00Jul 26, 2019 16:51:0000d:03h:59m:000s
32702019123FCSTSUMMJul 29, 2019 16:51:00Jul 29, 2019 20:27:0000d:03h:36m:000s
24652019127FCSTSUMMJul 31, 2019 11:48:00Jul 31, 2019 15:08:0000d:03h:20m:000s
10732019129FCSTSUMMAug 02, 2019 14:52:00Aug 02, 2019 18:39:0000d:03h:47m:000s
3692019130FCSTSUMMAug 05, 2019 17:45:00Aug 05, 2019 21:05:0000d:03h:20m:000s
9682019131FCSTSUMMAug 07, 2019 13:41:00Aug 07, 2019 17:01:0000d:03h:20m:000s
17532019132FCSTSUMMAug 08, 2019 14:31:00Aug 08, 2019 20:36:0000d:06h:05m:000s
18342019134UNUNOREFAug 13, 2019 14:22:00Aug 13, 2019 14:23:0000d:00h:01m:000s
8722019135FCSTSUMMAug 16, 2019 08:25:00Aug 16, 2019 14:13:0000d:05h:48m:000s

Last checked for outage data: 2019-08-23 05:22:52Z

Other links

GPS outages in a calendar format from AGI can be found here:

GPS Satellite Outage Calendar

Historical GPS Outages can be found here:

Historical GPS Satellite Outages

Navigation blog entries

Gps Basics
The basics of how GPS works with some technical content.

How Long Can You Use an Almanac?
GPS position data is contained in almanac files. Learn how long you can use these for analysis.

Selection of my published papers

Operational Considerations for Improved Accuracy with an IOC Galileo Constellation
This paper looks at how the Galileo operators can improve the performance of an initial Galileo constellation by managing their ephemeris and clock errors. Keeping those errors small can help keep initial positioning errors small, even when large DOPs are present.

Long term prediction of GPS accuracy - Understanding the Fundamentals
Topics on prediction methods for GPS and how long GPS errors can be predicted. Starting from an understanding of the elements of prediction, including almanac use and ephemeris and clock errors, I look at the statistics of GPS position error predictions under various scenarios.

Statistical Analysis of Military and Civilian Navigation Error Data Services
This paper examines the difference between ephemeris and clock errors generated using civilian data versus those generated using military data. The different data sources result from civilian GPS receiver and military GPS receiver.