Hi Also to the same point - which system is more reliable? You can ask the people who now use GPS how it compares in failure rate to what they used before. I know what kind of answers I get when I ask those questions ….
Bob On Jul 27, 2013, at 1:10 PM, Chris Albertson <albertson.ch...@gmail.com> wrote: > What is the failure rate? The number of failures does not matter unless > we know the total number of attempts. > > Do 1% of the ships that leave a harbor to become involved in an accident or > is it more like one in one ten million? > > I'd bet there are tens of thousands of cases of GPS failures where the user > said to himself "darn, it's broken" turned the thing off and went on his > way. > > > > > On Sat, Jul 27, 2013 at 1:51 AM, Robert Atkinson > <robert8...@yahoo.co.uk>wrote: > >> It seems you can't rely on the human backup. The UK Marine accident >> Investigation Branch Has recorded numerous accidents due to poor lookout. >> See >> http://www.maib.gov.uk/cms_resources.cfm?file=/KarinSchepersReportWeb.pdf >> http://www.maib.gov.uk/cms_resources.cfm?file=/CoastalIsle.pdf >> http://www.maib.gov.uk/cms_resources.cfm?file=/Beaumont.pdf >> http://www.maib.gov.uk/cms_resources.cfm?file=/Seagate_ReportWeb.pdf >> for recent examplesThe other problem is that AIS, a significant >> anti-collision aid, relies on GPS and is susceptable to spoofing. >> >> Robert G8RPI. >> >> >> ________________________________ >> From: Chris Albertson <albertson.ch...@gmail.com> >> To: j...@quikus.com; Discussion of precise time and frequency measurement >> <time-nuts@febo.com> >> Sent: Saturday, 27 July 2013, 4:18 >> Subject: Re: [time-nuts] GPS Spoofing >> >> >> I boat? The backup is a competent captain. He'd see the compass heading >> move and quickly disengage the autopilot. I had a boat for years I'd >> notice a 5 degree change. Mine was a sailboat so I'd be more sensitive to >> heading changes than a power boater but still the human is the backup. >> >> Most autopilots don't directly follow GPS, they use GPS to determine a >> heading, follow it then use GPS to detect drift and re-compute the heading. >> the heading would be held by a compass sensor in a low-cost setup or in a >> larger setup a lazer ring gyro backed up by a compass. So a spoofed GPS >> would cause the autopilot to "think" there was a bigger crooswnd or current >> and make a bigger heading change. >> >> I bet you could hijack a drone not a manned vehicle the pilot is trained to >> monitor the automation and he'd very quickly turn it off thinking it was >> broken. >> >> >> >> >> >> >> On Fri, Jul 26, 2013 at 8:41 AM, J. Forster <j...@quikus.com> wrote: >> >>> Prof. Humphry from Texas just reported being able to spoof GPS in the Med >>> and take over the nav system of a luxury yacht. He's done this before >> with >>> a drone in the US. >>> >>> LORAN as a backup, at least? >>> >>> -John >>> >>> ============== >>> >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >> >> >> >> -- >> >> Chris Albertson >> Redondo Beach, California >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > > -- > > Chris Albertson > Redondo Beach, California > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.