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GPSJam: Daily Maps of GPS Interference

gpsjam.org

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Re: GPSJam: Daily Maps of GPS Interference

#51

Post by _52co »

gdy wrote: post #33
fmajid wrote: post #22

Earlier quoted context omitted.

Perhaps they are jamming GPS and Galileo in favor of Glonass. They are certainly concerned about US GPS-powered artillery like the HIMARS given to Ukraine. They’d need fairly precise jammers because the frequencies are only 50MHz apart (GLONASS uses a frequency of 1.602 GHz, whereas GPS uses 1.57542 GHz).

You are underestimating how vast Russia (and Ukraine) are. Moscow is out of reach even for the longest range (300km) HIMARS missiles which are not supplied to the Ukraine. GPS jamming protects Russia's command and control structures from American intermediate range cruise missiles that can be launched from Mk41 launchers in Romania and Poland as well as from American ships.

Albeit ineffectively, because they have an INS backup.

Re: GPSJam: Daily Maps of GPS Interference

#52

Post by galangalalgol »

fmajid wrote: post #24
jjwiseman wrote: post #19

Earlier quoted context omitted.

I know the stories behind some of the regions, or at least some hypotheses. Interference in the U.S. is almost always the result of military testing or training. If you check against another map (Google maps, or skyvector.com/globe.adsbexchange.com to see sectional charts) you'll see that the interference region is usually centered on or close to a military base or Military Operations Area. There are often FAA notice…

In the US there were incidents with truckers using illegal jammers to defeat their employers’ GPS trackers: https://www.cnet.com/culture/truck-driver-has-gps-jammer-acc...

I read about the same thing affecting flights at Heathrow.

Re: GPSJam: Daily Maps of GPS Interference

#53

Post by the_biot »

mysterydip wrote: post #44

There was a spot I stood on in Japan probably 20 years ago that made my (handheld Garmin) GPS think I was traveling at something like 700mph at some angle across the globe. Once I left the area by maybe 10 feet, everything returned to normal. Went back to the spot, same thing. Always wondered what caused that.

The "travelling" part sounds like it could be an artifact of your GPS receiver interpolating between two vastly different location points, and interpreting that as moving between them -- at impossible speed/angle. So a single wildly wrong location could be enough to cause this.

Do GPS packets have a checksum?

Re: GPSJam: Daily Maps of GPS Interference

#54

Post by poulpy123 »

jjwiseman wrote: post #3

I made this site. Copying a comment I made on HN a few weeks ago: The ADS-B signals that many aircraft broadcast include not just the aircraft's GPS positions, but also a measure of GPS accuracy (strictly speaking, ADS-B doesn't talk about GPS specifically and can handle any sort of navigation technology; I'm sure there are some planes out there reporting positions based on inertial navigation systems, with correspon…

the european plate observing system has a subservice that distribute GPS data from GPS stations, including some ukrainian ones https://gnssdata-epos.oca.eu

I don't know if they are usable for your idea though

Re: GPSJam: Daily Maps of GPS Interference

#55

Post by the_biot »

jjwiseman wrote: post #19
graderjs wrote: post #9

This is fascinating. Really cool to see a map of GPS signals on Earth and the site looks really good, too. Love the colors and interface! Awesome :) Can anyone narrate any of the jammed signals? Like for instance what would be jamming in the ocean between Tripoli and Benghazi? Or what would be jamming around San Antonio, TX?

I know the stories behind some of the regions, or at least some hypotheses. Interference in the U.S. is almost always the result of military testing or training. If you check against another map (Google maps, or skyvector.com/globe.adsbexchange.com to see sectional charts) you'll see that the interference region is usually centered on or close to a military base or Military Operations Area. There are often FAA notice…

> Around Syria, C4ADS did some research a few years back identifying Russia as the main culprit

The amazing thing is that there's ADS-B data from Syria at all. Who in their right mind would fly over Syria? With ADS-B enabled, no less.

Re: GPSJam: Daily Maps of GPS Interference

#56

Post by martyvis »

the_biot wrote: post #53
mysterydip wrote: post #44

There was a spot I stood on in Japan probably 20 years ago that made my (handheld Garmin) GPS think I was traveling at something like 700mph at some angle across the globe. Once I left the area by maybe 10 feet, everything returned to normal. Went back to the spot, same thing. Always wondered what caused that.

The "travelling" part sounds like it could be an artifact of your GPS receiver interpolating between two vastly different location points, and interpreting that as moving between them -- at impossible speed/angle. So a single wildly wrong location could be enough to cause this. Do GPS packets have a checksum?

Id be fairly confident that they would. They also are encoded so that receivers that literally have no idea where they are can train on the received stream. Also don't forget that the receiver needs to hear signal from at least 3 or 4 satellites to be able to triangulate their position and altitude.

Re: GPSJam: Daily Maps of GPS Interference

#59

Post by the_biot »

martyvis wrote: post #56
the_biot wrote: post #53

Earlier quoted context omitted.

The "travelling" part sounds like it could be an artifact of your GPS receiver interpolating between two vastly different location points, and interpreting that as moving between them -- at impossible speed/angle. So a single wildly wrong location could be enough to cause this. Do GPS packets have a checksum?

Id be fairly confident that they would. They also are encoded so that receivers that literally have no idea where they are can train on the received stream. Also don't forget that the receiver needs to hear signal from at least 3 or 4 satellites to be able to triangulate their position and altitude.

The wikipedia page has some info, looks like various CRC and parity checks. Maybe the receiver was just ignoring them, and receiving faulty data.

I dunno, it seems to me like that GPS receiver had fairly bad software. If you get packets from a bunch of different satellites but one is way off, it seems like good sense to throw that one away.

Re: GPSJam: Daily Maps of GPS Interference

#60

Post by TechBro8615 »

londons_explore wrote: post #50
formerly_proven wrote: post #48

Earlier quoted context omitted.

It is alleged that the RQ-170 was expressly designed for risky operations (where loosing it eventually is likely, and retrieval/destruction may not be possible) and so was created without sensitive technology.

The crypto for US military GPS uses the same keys worldwide, and rotated ~ weekly. That means if you capture any device which has the crypto keys, then you can spoof military GPS for the rest of the week, allowing you to do lots more damage. Therefore, the military often doesn't even use the keys in their own devices.

How do you know this?
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