Just read a disturbing article in Business and commercial aviation magazine march 2019 issue. Essentially it said that the GPS signals may be subject to either interntial or unintentional interferrrence especially in the L1 band. Additionally spoofing or jamming by regular persons is also possible.
Some listed jamming. Is being done by truckers who want to fool some toll both receivers and trucking company monitors. ( shadow take note ) Pokemon players have used jammers to spoof other players. Some taxi cabs have had jammers to confuse Uber. Drone operators have used jammers as well to fly into restricted areas. Can't you imagine a RR line running along a highway along side a jaming truck? Or a parked truck along side any major rail line. But the FCC has also found some fixed location jamers. Makes one wonder if that could have been a problem for the Denver "A" line.
To top it off the US government is required by executive order to conduct periodic tests of jamming. I receive 2 - 3 notams a month of such tests. Usually they are near Wllops, CHS, Cape canaveral, Ft. walton beach, or west coast but a couple in the middle of the US.
Do the RRs even get copies of these notams of these gamming events ? All in all make me wonder about putting all our eggs for anything pertaining to GPS in one basket
GPS is also used for timing celluar and fiber networks as well as power line monitoring.
This is a big risk that has been ignored
Surveyors knew about it. Deal with it regularly. (if you look at the old PTC threads, it will show up in comments from several of us on the forum)
Signals don't have to be jammed, just delayed or distorted in order to screw things up. (MultiPath) Now you know why the surveying community is so frustrated with LightSquared/Ligado trying to steal bandwidth from GPS applications that had that dedicated bandwidth. Enough problems trying to make sure the locomotives are properly shielded from emmitting EMF forces disrupting the signal. The older the locomotive, the worse it gets, generally.)
rdamonGPS is also used for timing celluar and fiber networks as well as power line monitoring. This is a big risk that has been ignored
The military's smart weapons in many cases also rely on GPS signals.
Never too old to have a happy childhood!
BaltACDThe military's smart weapons in many cases also rely on GPS signals.
Military GPS system for targeting is seperate from civilian GPS and also more accurate. Also, only some smart weapons use GPS, enough weapons do not use GPS that an opposing force is still screwed if they figure out a way to jam the military GPS system. The coolest guidance system in my opinion is that used by Cruise Missiles which uses digitized terrain maps captured by satellite photography. They use those instead because the Cruise Missile uses terrain as part of cover on it's low and slow flight to avoid shoot down.
Tried to find a link for readers here to link to. However since I also receive a e copy cannot separate out possible free link(s) that would be available. Here is link that is paywalled and maybe someone can find free link? Article is 6 full pages long.
https://secure.viewer.zmags.com/publication/1c825223#/1c825223/1
To carry on the article mentioned several incidents where aircraft have had some problems that have crashed the airplane's flight management system. There is one type of advanced FMS on Max-9 aircraft. What is scary for aviation that some incidents have occurred degrading airborne collision prevention systems ( TCAS ) and worse still airplanes on final approach to airports especially airports with truck traffic close by. Fortunately those incidents occurred in good visual days.
Hopefully we will never have to say " heard it here first ".
blue streak 1 Just read a disturbing article in Business and commercial aviation magazine march 2019 issue. Essentially it said that the GPS signals may be subject to either interntial or unintentional interferrrence especially in the L1 band. Additionally spoofing or jamming by regular persons is also possible. Some listed jamming. Is being done by truckers who want to fool some toll both receivers and trucking company monitors. ( shadow take note ) Pokemon players have used jammers to spoof other players. Some taxi cabs have had jammers to confuse Uber. Drone operators have used jammers as well to fly into restricted areas. Can't you imagine a RR line running along a highway along side a jaming truck? Or a parked truck along side any major rail line. But the FCC has also found some fixed location jamers. Makes one wonder if that could have been a problem for the Denver "A" line. To top it off the US government is required by executive order to conduct periodic tests of jamming. I receive 2 - 3 notams a month of such tests. Usually they are near Wllops, CHS, Cape canaveral, Ft. walton beach, or west coast but a couple in the middle of the US. Do the RRs even get copies of these notams of these gamming events ? All in all make me wonder about putting all our eggs for anything pertaining to GPS in one basket
Some listed jamming. Is being done by truckers who want to fool some toll both receivers and trucking company monitors. ( shadow take note ) Pokemon players have used jammers to spoof other players.
Some taxi cabs have had jammers to confuse Uber.
Drone operators have used jammers as well to fly into restricted areas. Can't you imagine a RR line running along a highway along side a jaming truck? Or a parked truck along side any major rail line. But the FCC has also found some fixed location jamers. Makes one wonder if that could have been a problem for the Denver "A" line.
BS1, Has delivered some information that many of us who are interested, but on the sidelines of RilfFANING; have probably not thought of, because we are not directly effected by jamming ( of radios?) , spoofing, (except. where tele-marketers are concerned?), and the ocassional GPS directional screw-up, qhile driving.
The Federal mandates concerning PTC installation, do not seem to consider anything beyond its compleation[PTC's] across the National Railroad Network. It sure sounds like the Legislative Branch has required a serious potential trap, into which they have herded the railroad industry?
Collateral damage would also seem to be built into the Trucking Industry, with the forced re-jiggered, driver hours of service, and electronically, collected log timing.
Having been away from the business for 19 years, and aware of some of the problems addressed by the 'new rules and regs'.
Not to mention, the 'resourcefulness' of individuals, that existed in the 'escape and evasion' of those earlier laws [HOS ], and national 55 mph speed limit. It only stands to reason that when the Government, seeks a 'one size fits all' solution, they will find their best efforts circumvented, or even neutralized? SO! Wonder what happens next? Will the march of technology continue to run over the legislators, and deepen the 'traps' they've created for society?
Most military prcision weapons depend on an invisable laser beam to guide the bomb to its target. It is scary to think that the PTC system can be jamed or hacked.
Caldreaner
IIRC, at least some portions of PTC use non-GPS based locating mechanisms (transponders, etc), which might help some.
I would think that it would take a pretty strong signal to knock out GPS for any distance - and that would attract attention. In the case of a truck running alongside the tracks, the outage might lengthy, but for a fixed jamming station, the outage will be relatively brief and the effect mitigated by other methods of tracking.
Still, it is a problem.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
You are right Mudchicken, I thought it was familiar when I was typing about this.
There are about 5 other countries with their own systems and with all the new commercial launch companies it may be more soon. I know the power industry is looking at adding more Rubidium oscillators in their network so they are not directly timing off GPS.
tree68IIRC, at least some portions of PTC use non-GPS based locating mechanisms (transponders, etc), which might help some. I would think that it would take a pretty strong signal to knock out GPS for any distance - and that would attract attention. In the case of a truck running alongside the tracks, the outage might lengthy, but for a fixed jamming station, the outage will be relatively brief and the effect mitigated by other methods of tracking. Still, it is a problem.
Even transponders use 'radio frequency' to communicate with the devices they work with. The radio frequency spectrum can be degraded by any number of issues, some of which we don't fully understand. When we look to systems like PTC wherein we are placing 100% trust in their proper operation - to the extent those systems require radio frequency communication the reliability cannot be 100%. Close but not 100%
BaltACD tree68 IIRC, at least some portions of PTC use non-GPS based locating mechanisms (transponders, etc), which might help some. I would think that it would take a pretty strong signal to knock out GPS for any distance - and that would attract attention. In the case of a truck running alongside the tracks, the outage might lengthy, but for a fixed jamming station, the outage will be relatively brief and the effect mitigated by other methods of tracking. Still, it is a problem. Even transponders use 'radio frequency' to communicate with the devices they work with. The radio frequency spectrum can be degraded by any number of issues, some of which we don't fully understand. When we look to systems like PTC wherein we are placing 100% trust in their proper operation - to the extent those systems require radio frequency communication the reliability cannot be 100%. Close but not 100%
tree68 IIRC, at least some portions of PTC use non-GPS based locating mechanisms (transponders, etc), which might help some. I would think that it would take a pretty strong signal to knock out GPS for any distance - and that would attract attention. In the case of a truck running alongside the tracks, the outage might lengthy, but for a fixed jamming station, the outage will be relatively brief and the effect mitigated by other methods of tracking. Still, it is a problem.
Correct about the timing. That would mess up RFI IDs for toll roads and RR car readers. So way for trucks to avoid payingtolls and persons in cars as well. We can well imagine that the sellers of receiving and jammers would not kwant this well known?
Did any of you know that gas station credit card readers use GPS timings to verify accounts. There have been reports that some station's pumps have tmporarily not worked especially truck stops. Wonder if the signals were jammed by a truck? We have not experienced such but has anyone here?
As far as in store readers probably not since they would be shielded by buildings from GPS ?
It depends on what and how they're jamming. If they are specifically jamming GPS by transmitting on the GPS frequencies, they won't disrupt much of anything else. OTOH, if they're blasting out the RF equivalent of white noise, then they will, indeed wipe out anything that is RF based.
tree68 It depends on what and how they're jamming. If they are specifically jamming GPS by transmitting on the GPS frequencies, they won't disrupt much of anything else. OTOH, if they're blasting out the RF equivalent of white noise, then they will, indeed wipe out anything that is RF based.
But tree RFIDs depend on clean GPS signals. Also Gas station pump credit card reads among other items. Even EMF from locos as MC listed can jam GPS PTCs. Had not realized but maybe shielding is why the loco receiving antenna boxes on top of locs are so large ? It sure gets complicated ?
Basic RFID does not require a GPS signal - those little grey boxes you see on the sides of virtually every locomotive and freight car are RFID tags. Trackside scanners emit a signal and the RFID tag responds. That key fob you use to open the doors at work is RFID.
That's not to say that a communications system used to transmit the data from the RFID tags doesn't use GPS timing.
My furnace can affect reception on my amateur radio equipment - essentially "jamming" wide ranges of radio spectrum. Those of a certain generation will remember hearing the "tick tick tick" of the spark plugs on their car's AM radio.
MC is right about locomotives - between the alternators and the power handling circuitry (they're all electronic now), the potential for interference is very high.
The power supplies I use for my amateur radios have an adjustment knob that can be used to tune out interference generated by the power supply.
GPS only uses two specific radio frequencies - it would not be difficult to cause interference on those specific frequencies without affecting other RF operations.
Those domes you see on top of the windscreens on semis house their GPS antennas. Given the importance of GPS to PTC, I'm not surprised they would use a substantial antenna.
The other thing that drives surveyors nuts when using GPS in a precision application is SCADA radio applications in industrial plants, etc. I still have nightmares about what a certain ethanol plant at Grand Junction. IA (Jeff H knows it well) did to a topo survey we did there. ("Flyers" and anomolies deluxe, the interference was that bad.)
Surveyors can sit and look at the data collected and throw out any goofy spikes and or data fails - PTC, in real-time, can't really do that.
tree68Basic RFID does not require a GPS signal - those little grey boxes you see on the sides of virtually every locomotive and freight car are RFID tags. Trackside scanners emit a signal and the RFID tag responds. That key fob you use to open the doors at work is RFID. That's not to say that a communications system used to transmit the data from the RFID tags doesn't use GPS timing. My furnace can affect reception on my amateur radio equipment - essentially "jamming" wide ranges of radio spectrum. Those of a certain generation will remember hearing the "tick tick tick" of the spark plugs on their car's AM radio. MC is right about locomotives - between the alternators and the power handling circuitry (they're all electronic now), the potential for interference is very high. The power supplies I use for my amateur radios have an adjustment knob that can be used to tune out interference generated by the power supply. GPS only uses two specific radio frequencies - it would not be difficult to cause interference on those specific frequencies without affecting other RF operations. Those domes you see on top of the windscreens on semis house their GPS antennas. Given the importance of GPS to PTC, I'm not surprised they would use a substantial antenna.
Several years ago - about 2008-2009 range the CSX signal system between F Tower and JD Tower would take a 'hit' - lined signals would go into 'time' without the Dispatcher having knocked the signals down to line another route.
Several months of investigation indicated that the problem was that Amtrak's electrified Main Tracks paralleled the CSX tracks from F Tower for almost a mile. Power fluctuations on Amtrak was putting out electrical interference that interacted with the CSX signal system. Appropriate changes were made and after nearly two years the problem was fixed.
There are a whole lot of radio frequency waves floating around in out 21st Century everyday world - RF that we take for granted and give no thought to - AM, FM, Short Wave, TV, Weather Radar, Microwaves, door openers, radar detectors, cell phones - and probably a thousand other things I can't recall or don't know about.
BaltACDThere are a whole lot of radio frequency waves floating around in out 21st Century everyday world - RF that we take for granted and give no thought to - AM, FM, Short Wave, TV, Weather Radar, Microwaves, door openers, radar detectors, cell phones - and probably a thousand other things I can't recall or don't know about.
Not only that, but propogation does change. I take part in a regular morning amateur radio net that runs on a 2 meter (just below VHF high band commercial/emergency services) repeater about 40 or so miles from the house. Most days it comes in just fine, but some days I can hardly hear it.
MC:
LightSquared? Maybe the the best thing to do with that crowd is to strap them into a a "passenger drone" prgrammed to do terrain following guided only by GPS over an area populated with their proposed ground stations. There was a very good reason that the frequencies were set aside for satellite downlinks. I also think that anyone in any recent administration was in favor of this disasterously bad idea should be forever banned from anything to do with radio communication if not prosecuted for endangering the public.
Multipath problems can be reduced with changes in antenna design, though these changes will add to the size and cost of the antenna. One approach would be to use a phased to focus reception on where the satellite is expected to be - which also improves against attempts at jamming or spoofing. Big downside is antenna will be much bigger and receiver will be much more expensive.
Tree:
Having spent most of my life near the southern California coast, I'm very familiar with the effects of inversion layers on VHF propagation. One of the more interesting examples was a contact with someone at UCSB on 223.5 when I was in San Diego using a mag mount antenna sitting on a suitcase and running 1 watt. For GPS it is the variations in the ionosphere that effect the velocity of propagation which then causes the apparent receiver position to move, though that can be countered by ground sations broadcasting the correction factors.
One final to help the situation is that the latest batch of GPS birds have a higher transmitter output power.
The utiity I worked for before retiring had a large microwave (About 60 links) network using 2 gHz & 6 gHz spectrum for voice and data which has almost been completely retired and replaced with fiber optic ring networks. FCC wanted to sell the 2 gHz spectrum bands for use by cellular and other commercial money makers. Fiber does not have interference issues that I am aware of yet. But the meter reading and distribution automation systems use RF spectrum to transmit meter readings back to the company computers to send billing and outage data plus control distribution automation switches. The RF net can also be used to disconnect a non-paying customer. Time will tell whether mischief can occur.
So we know that Space weather can affect GPS. Here is a briefing of such.
https://www.swpc.noaa.gov/impacts/space-weather-and-gps-systems
https://www.swpc.noaa.gov/phenomena/geomagnetic-storms
https://www.swpc.noaa.gov/impacts/electric-power-transmission
https://www.swpc.noaa.gov/impacts/hf-radio-communications
blue streak 1So we know that Space weather can affect GPS. Here is a briefing of such. https://www.swpc.noaa.gov/impacts/space-weather-and-gps-systems https://www.swpc.noaa.gov/phenomena/geomagnetic-storms https://www.swpc.noaa.gov/impacts/electric-power-transmission https://www.swpc.noaa.gov/impacts/hf-radio-communications
Where is the Magnetic Equator in relation to the Geographic Equator!
BaltACDWhere is the Magnetic Equator in relation to the Geographic Equator!
Here is a little back ground that might help put that in perspective:
https://en.wikipedia.org/wiki/North_Magnetic_Pole
Convicted One BaltACD Where is the Magnetic Equator in relation to the Geographic Equator! Here is a little back ground that might help put that in perspective: https://en.wikipedia.org/wiki/North_Magnetic_Pole
BaltACD Where is the Magnetic Equator in relation to the Geographic Equator!
I am fully aware that the North Magnetic Pole is not at the North Geographic Pole and that it moves around some. I am also aware that the Magnetic Poles have swapped several times during the history of the 3rd rock from the Sun. That is why I was asking the question about the Magnetic Equator - which was what had been mentioned in the link.
The magnetic equator varies from the geographic equator just as the magnetic axis varies from the geographic axis.
The second paragraph (beginning with the words "The positions of the magnetic poles can be defined...") might be more useful:
https://en.wikipedia.org/wiki/Earth%27s_magnetic_field#Magnetic_poles
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