[SystemSafety] GPS jamming

SPRIGGS, John J John.SPRIGGS at nats.co.uk
Fri Jul 12 11:40:36 CEST 2019

Hi Dewi,
The original article does not tell us enough; if it were an airliner, it could not use ‘vanilla GPS’ and would have to have the RAIM capability mentioned in 1.7.1 of the document to which you linked.
I suspect that it was one of those small aircraft that have a GPS antenna stuck to the windscreen, which can itself degrade the solution by occluding satellites.


From: systemsafety <systemsafety-bounces at lists.techfak.uni-bielefeld.de> On Behalf Of Dewi Daniels
Sent: 12 July 2019 10:25
To: The System Safety List <systemsafety at techfak.uni-bielefeld.de>
Subject: Re: [SystemSafety] GPS jamming

I'm puzzled. I thought the whole point of WAAS (and EGNOS) was that the pilot would be alerted if the GPS calculated position is inaccurate. See section 1.7.2 of  https://www.gps.gov/technical/ps/2008-WAAS-performance-standard.pdf<https://www.gps.gov/technical/ps/2008-WAAS-performance-standard.pdf> . Why was the pilot not alerted in this instance? Was he not using a WAAS receiver? If not, why was he relying on a vanilla GPS receiver for navigation?


Dewi Daniels | Director | Software Safety Limited

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On Wed, 10 Jul 2019 at 12:49, Robert P. Schaefer <rps at mit.edu<mailto:rps at mit.edu>> wrote:
Thought this would be of interest:

NASA report: Passenger aircraft nearly crashes due GPS disruption


Along the lines of “Who the heck would jam GPS in the continental US?”,
I’ve got an anecdotal story from one of Haystack’s scientists who was trying to collect GPS data
(L1, L2 data is useful for measuring solar activity in the Ionosphere) during the solar eclipse in August 2017.
He was unable to collect data because of GPS jamming. The story was that truckers use GPS jammers so they
won’t be tracked by their employers.

bob s.
research engineer
MIT haystack observatory
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