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Old 06-02-2019, 13:28   #1
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GPS Jamming Feb 2019

This was just announced by the US government for pilots that use the same GOS signals as GPS, ADS-B outages
“GPS air navigation and automatic dependent surveillance-broadcast service may be unreliable or unavailable in a vast swath of airspace in the eastern US and the Caribbean during a military exercise involving GPS jamming today through Feb. 10. “
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Old 06-02-2019, 14:18   #2
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Re: GPS Jamming Feb 2019

It sounds like this is primarily a degrading of the GPS signal, such as disabling WAAS.
The airlines have an interesting out:
Pilots who encounter hazardous interruption of GPS navigation or who have flight-control issues should be aware that they can say the phrase “Stop buzzer” to air traffic control, which initiates the process of interrupting the testing to restore navigation signal reception, Duke said.

During previous GPS-interference events, pilots declared emergencies, but the jamming continued because ATC did not understand that the emergency was related to the GPS interference. According to the Pilot/Controller Glossary, “stop buzzer” is a term used by ATC to request suspension of “electronic attack activity.” Pilots should only use the phrase when communicating with ATC, or over the emergency frequency 121.5 MHz, if a safety-of-flight issue is encountered during a known GPS interference event. Using this unique phrase when experiencing an unsafe condition related to GPS interference will ensure that ATC and the military react appropriately by stopping the jamming, Duke said.

“Pilots should only say ‘stop buzzer’ when something unsafe is occurring that warrants declaring an emergency. They should make sure ATC knows that the emergency is GPS-related and that halting the GPS interference will resolve the emergency,” he said.
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Old 22-02-2019, 17:33   #3
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Re: GPS Jamming Feb 2019

This notice informs the public that the Space and Missiles Center Global Positioning Systems (GPS) Directorate Engineering (SMC/GPE) Systems Integration Demonstration (SI Demo) team plans to execute a test in February 2019 to investigate legacy receiver week roll-over behavior and analyze any off-nominal behavior exhibited. Additonal details about the test and how interested civil vendors may participate is detailed below.

Questionaire due by February 4, 2019.

SMC/GPE, 483 North Aviation Boulevard, El Segundo, CA 90245-2808.

The Global Positioning System (GPS) week number rollover occurs in the GPS legacy navigation (LNAV) message every 1024 weeks due to the GPS week number being represented by only 10 bits within the LNAV message. The next GPS week number roll over will occur 18 seconds prior to the 0000Z boundary (Coordinated Universal Time) between April 6/7 2019. In most cases, any negative response from a GPS receiver caused by a problem accounting for the 10-bit week number week roll over would likely affect the calendar conversion from GPS time to UTC date/time and could result in the GPS receiver thinking it had jumped backward in time by 1024 weeks to 21/22 August 1999. Many receiver-specific design documents contain requirements that ensure proper handling of a rollover event. However, SMC/GPE does not control, maintain, or even have an awareness of the software and requirements baseline of every GPS receiver in operation. Many performance conditions, especially those in older GPS receivers, may differ from expectations laid out in modernized receiver-specific design documents. It should be noted that the modernized civil navigation (CNAV) signals all utilize a 13-bit week number representation and the use of those CNAV signals can delay potential week number roll-over problems to 5/6 January 2137. Below are a few questions whose answers would help SMC/GPE understand your receiver's expected behavior during the upcoming GPS 10-bit week number roll-over:
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