I think the GPS backups are called, - GLONASS <https://en.wikipedia.org/wiki/GLONASS> - Galileo<https://en.wikipedia.org/wiki/Galileo_%28satellite_navigation%29> - IRNSS<https://en.wikipedia.org/wiki/Indian_Regional_Navigational_Satellite_System> - Compass <https://en.wikipedia.org/wiki/Compass_navigation_system>
They should all be up and running, especially the first two in 5 to 7 years. But ALL radio navigation systems can be spoofed. The ones you can't spoof are On Sun, Jul 28, 2013 at 2:03 AM, stew...@g3ysx.org.uk <stew...@g3ysx.org.uk>wrote: > LF is much easier to accurately DF than VHF and above due to multipath > effects. > > Stewart > > Sent from my iPad > > On 27 Jul 2013, at 21:44, Bob Camp <li...@rtty.us> wrote: > > > Hi > > > > A Loran jammer would / could work with a *much* smaller antenna if a > local area was the target. Power is easy at 100 KHz. Loran is no easier / > harder to DF than GPS. > > > > Bob > > > > On Jul 27, 2013, at 3:37 PM, Scott McGrath <scmcgr...@gmail.com> wrote: > > > >> LORAN was/is not perfect geographic features could and did limit > reception However an effective jammer would need effective power in the > hundred watt range and a efficient antenna system plus a connection to > power grid or small Genset. > >> > >> Not amenable to easy concealment and fairly easy to DF using standard > techniques especially since location of real station well known and fixed > >> > >> An effective GPS jammer which can take out a few square miles is the > size of a trade paperback and runs on batteries and costs under 50 bucks to > build > >> > >> Imagine a scenario where a few hundred of these are deployed with > hostile intent. > >> > >> Military and Civillian systems are now useless due to nature of signal > they are hard to DF > >> > >> Sent from my iPhone > >> > >> On Jul 27, 2013, at 2:09 PM, Bob Camp <li...@rtty.us> wrote: > >> > >>> Hi > >>> > >>> Loran can / could easily be jammed over a limited area, just like GPS. > Nothing crazy large or expensive would be required. The same sort of > "malfunctioning this or that" took out Loran from time to time over harbor > sized areas. Loran had so many issues with dropping out, that they simply > were not worth talking about …. > >>> > >>> Bob > >>> > >>> On Jul 27, 2013, at 1:35 PM, Scott McGrath <scmcgr...@gmail.com> > wrote: > >>> > >>>> Key > >>>> > >>>> Problem with GPS is its easy to spoof on one level and have a > complete denial of service on the other. Out in California a while back a > malfunctioning TV distribution amplifier jammed a major harbor and > surrounding almost 25 sq miles affected all because of a 49.95 TV amp had a > problem. The military receivers had the same problem > >>>> > >>>> LORAN is virtually jam proof unless you have a very powerful > transmitter > >>>> > >>>> Sent from my iPhone > >>>> > >>>> On Jul 27, 2013, at 11:17 AM, Michael Perrett <mkperr...@gmail.com> > wrote: > >>>> > >>>>> I have seen a lot of differing opinions on GPS Spoofing and using > back up > >>>>> systems on this thread. Most pretty good, but a couple off the mark > a bit. > >>>>> > >>>>> Here are a couple of comments on GPS Spoofing. > >>>>> > >>>>> - There are anti-spoofing GPS receivers available - to "authorized" > >>>>> users. Typically DOD. Most, if not all, military receivers utilize > the > >>>>> encrypted "P-Code", while civilians must use the more vulnerable > clear text > >>>>> "C/A code". The P-Code signals are very difficult to spoof unless > you have > >>>>> a-pirori knowledge. The newer satellites (GPS III) will have an even > more > >>>>> robust AS methodology. > >>>>> - Note: beware of P-Code, or Military, receivers available on eBay. > >>>>> They are useless without the encryption keys distributed by the US > >>>>> Government. > >>>>> - In the (near?) future there will be four civilian GPS Signals: > "The > >>>>> government is in the process of fielding three new signals designed > for > >>>>> civilian use: L2C, L5, and L1C. The legacy civil signal, called L1 > C/A or > >>>>> C/A at L1, will continue broadcasting in the future, for a total of > four > >>>>> civil GPS signals. Users must upgrade their equipment to benefit > from the > >>>>> new signals". ref > >>>>> http://www.gps.gov/systems/gps/modernization/civilsignals/ > >>>>> - Receivers utilizing the new civilian GPS frequencies can solve the > GPS > >>>>> equations from more than one frequency and see if any one signal is > being > >>>>> spoofed. The new civilian frequencies will be more spoof resistant. > >>>>> > >>>>> Comments on using inertial measurement units (IMUs) to back up GPS. > >>>>> > >>>>> - Current IMUs with even a "good" drift rate of say, 1 degree per > hour, > >>>>> available for around a few thousand dollars, will be off 60 nautical > miles > >>>>> after an hour of uncorrected operation. That can be reduced by other > sensor > >>>>> inputs (GPS, LORAN, pit-log or what ever you have), but the > navigation > >>>>> solution will eventually degrade to the accuracy of the external > sensor. If > >>>>> my memory serves me for a really deep pocket navigator (having tens > to > >>>>> hundreds of thousands of dollars, and a large amount of available > mounting > >>>>> space) IMUs with drift rates of up to a thousand times less can be > >>>>> purchased (that's ,001 miles per hour, or around a couple of meters > per > >>>>> hour), think submarines, etc. > >>>>> > >>>>> Using a dual sensor navigation system (or timing system! ), such as > >>>>> GPS/eLORAN, would obviously make the system so much more robust. > >>>>> > >>>>> Michael / K7HIL > >>>>> > >>>>> On Sat, Jul 27, 2013 at 6:43 AM, Scott McGrath <scmcgr...@gmail.com> > wrote: > >>>>> > >>>>>> Key here is how does the captain know that GPS is no longer > providing an > >>>>>> accurate fix? You need 2 or more independent systems to cross > check each > >>>>>> other. > >>>>>> > >>>>>> Sent from my iPhone > >>>>>> > >>>>>> On Jul 27, 2013, at 12:21 AM, Jim Lux <jim...@earthlink.net> wrote: > >>>>>> > >>>>>>> On 7/26/13 8:45 PM, J. Forster wrote: > >>>>>>>> I gather from the article, the GPS position was spoofed and the > >>>>>> autopilot, > >>>>>>>> in bringing it back to where it was supposed to be, actually took > it off > >>>>>>>> course. > >>>>>>>> > >>>>>>>> There are places where a few hundred feet makes a big difference, > viz. > >>>>>> the > >>>>>>>> Costa Concordia. > >>>>>>>> > >>>>>>>> IMO, this is a very convincing reason for something like LORAN. > >>>>>>> > >>>>>>> I think it's a convincing argument for a captain who pays > attention to > >>>>>> the other navigation instruments and doesn't blindly follow the GPS. > >>>>>>> > >>>>>>> It's also a convincing argument that shipboard > >>>>>> automation/autopilot/autocontrol vendors need to make more > sophisticated > >>>>>> software (which I suspect they do, particularly on 200+ foot > ships.. I > >>>>>> would imagine that there are some aspects of this demo that are > contrived.) > >>>>>> The ship making and driving business is pretty unregulated. It's > all about > >>>>>> what the owner of the ship is willing to pay (or what he needs to > get > >>>>>> liability insurance, if he wants). There's nothing even remotely > like > >>>>>> DO-178 for shipboard stuff. > >>>>>>> > >>>>>>> The folks doing stabilized oil rigs probably have sophisticated > systems, > >>>>>> but they're also using IMUs and other stuff. Ditto for high value > things > >>>>>> (oil tankers, warships). Molasses tankers? They're probably lucky > to have > >>>>>> a functioning compass and some old charts. > >>>>>>> > >>>>>>> > >>>>>>> I'm not sure, though, that looking at the big picture, whether > your tax > >>>>>> dollars are better spent on LORAN, or on some other precision > navigation > >>>>>> method or on making jam resistant GPS receivers (which do, in fact > exist, > >>>>>> and make use of things like direction of arrival of the signal..) > >>>>>>> > >>>>>>> Note that a GPS system with 3 antennas (as is common in systems > that use > >>>>>> GPS to derive attitude/orientation) would be extremely difficult to > spoof, > >>>>>> and would be VERY inexpensive to implement. Either the carrier > phases and > >>>>>> code phases are consistent for all the received signals or they're > not. A > >>>>>> jamming signal coming from the wrong direction will not have the > right > >>>>>> direction of arrival relative to the platform orientation. One > wrong > >>>>>> signal might be tolerable (multipath, etc.) but with a multi > satellite fix, > >>>>>> I suspect it would be hard to do it. > >>>>>>> > >>>>>>> Sure, one could throw up N pseudolites on a bunch of UAVs, etc., > but > >>>>>> that's getting to be a bit noticeable. > >>>>>>> > >>>>>>> > >>>>>>> For what it's worth, I don't know that LORAN has the performance to > >>>>>> avoid a Costa Concordia type foul up (assuming they were crazy > enough to do > >>>>>> the near pass in the fog, so visual navigation didn't work) > >>>>>>> > >>>>>>> I seem to recall that LORAN had 1/4 nmi kinds of accuracy. it > would get > >>>>>> you to the channel or mouth of the harbor, but not get you into > your berth. > >>>>>> You might be familiar with the local propagation anomalies and get > better > >>>>>> accuracy with experience in your local waters. > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> > >>>>>>>> > >>>>>>>> -John > >>>>>>>> > >>>>>>>> ================= > >>>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>>> 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. > >>>>>> _______________________________________________ > >>>>>> 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. > >>>> _______________________________________________ > >>>> 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. > >> _______________________________________________ > >> 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. > _______________________________________________ > 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.