Wikimeida Commons

Periodically RNTF posts information drawn from GPS disruption reports sent to the US government and others over the last several years. We endeavor to include enough information to make them helpful to our readers while preserving the anonymity of the reporting parties.

Report Narratives:

≈ 5 days “Dear Sir/Madam, Yesterday, the following message has been received in XXX Helpdesk related to some interference issues in GPS signal reception in TMA in Madrid: Since February the 17th in the afternoon, several airlines have reported problems receiving GPS signal when executing the RNAV-1 SID procedures in both northern and southern runways. The GPS signal’s lost is detected by the airplanes when they reach more than 1000 ft and it is not recovered until the plane is at more than 10000 ft. A flight verification has taken place the 20th, detecting an interference in the 1575.02 MHz frequency and a potential location for the source of it. An interference near that position was discovered thanks to detection ground equipment and it was removed the 22nd. However, more GPS signal’s lost reports have arrived from the pilots after removing the potential source of interference. Please, could your expert team investigate this event and share with us the reason of this inferences as to solve the incident as soon as possible?. Thank you in advance. P.S.: Please, as a reminder, use our XXX-operations email for replying. Kind regards, XXX Helpdesk team. Report Submitted 23 February 2016

≈ 35 days “PRN18 has been unusable by all GBAS Landing systems (US, Europe, Asia, Africa, South America) since March 8th, 2016 due to a failure of our Signal Quality Monitor (SQM). This has impacted system availability of the GBAS Landing System across the globe. The FAA has informed us that WAAS has also identified this issue as observed by a sudden jump in range error on PRN18 on March 8.” – Report Submitted 13 April 2016

≈ 30 days “Since the beginning of July 2016 [Airline Name] Airbus A330 aircraft arriving at or departing from, or flying over Manila have been reporting either a “GPS FAULT” condition affecting both GPS receivers (MMR), or engineering monitoring of GPS receiver (MMR) performance has detected that the receiver has been unable to calculate the Autonomous Horizontal Integrity Limit (HIL) value required by FAA TSO-C129a on either GPS receiver. This is known to be an indicator of possible interference of the GPS signal. Note that the number of GPS satellites being track at the time of occurrence is unknown.” Report Submitted 8 August 2016

Unknown “There is a small corridor between the Class Bravo of Phoenix and Class Delta of Chandler airport in Arizona that has a constant loss of GPS signal…In between Chandler, AZ airspace and Stellar Airpark” – Report Submitted 8 February 2017, no resolution date listed

≈ 82 days “The GPS systems in normal mode, not military, have been interrupted since the installation of the Homeland Security Drone command and control system at the North End of our airport. During testing with Homeland Security, the problem has been confirmed to affect both ground and air operations at and within 15 miles South of the airport.” Date of Incident 3 January 2017, Report Submitted 22 March 2017

≈ 1 day “GPS reception was intermittent all day, when receiving a signal location was off by over 1000 feet, this was experienced while driving and while stationary flying multiple drones and lasted most of the day and was very unusual.” 24 June 2017

Blog Editor’s Note: Information for this post was drawn from reports received by the U.S. Coast Guard Navigation Center.