Jamming a GPS signal is not that hard - the amount of energy received by the antenna is minimal and can easily be jammed by a source on the ground. Anti-jamming GPS antennas detect jamming and "null" out the signal for that quadrant - just think of an antenna as a pie, all sliced up - if one segment is jammed, that slice of pie's information is discarded until the jamming goes away. The amount of satellites you recieve on your omni-directional GPS antenna will probably be lowered, but at least your signal won't disappear completely. (I don't have the links handy that explain this better)
"Spoofing" the signal is much more difficult and is damn near impossible..(at least we think...) for a GPS that is getting signals from the satellite constellation. The only true way to spoof a GPS reciever would be to bring it into a closed room and set up a simulated constellation for the reciever to lock on to. Some universities have done this type of research in an effort to provide robots with a sense of location.
The GPS string that is sent out by the reciever is defined by standards and is in plain text. The RMC, GGA, VTG sentences that are output are enough to give location, altitude, ground speed, etc. To simulate actual reception, all you have to do is playback a recorded text file of a previous reception. Heck, you wouldn't even need to use a recorded file - just make a script/program to spit the data out over the com/usb port. Hence, for this to be secure... The link from the GPS to the crypto black box had better be encrypted... But then how secure is that encryption? If this was a military only device where encryption is relied upon using their crypto devices and keytapes...then this thing could be robust. Once out into the civilian sector, they won't have the same level of encryption.
What happens if I've got two conference rooms in the same building, both needing access, but both belonging to a different company? Will both companies look the same w/regards to GPS crypto?
What's the "threshold" that the GPS system will accept as being "close enough"? Here's something to try...this assumes a GPS without the secret crypto keys loaded to get the "best" position. Start up a gps and keep logging the position that it thinks its at. This position will change ever so slightly over time. Reboot the GPS, compare the position on reboot...it will be a little bit different...(depending on how precise you want those co-ordinates)
My point is that there will have to be some "slop" allowed...some noise level that will need to be allowed into the system.
These are the things that could be used to exploit it.
The email test triggered a weakness in the version of Lotus Domino software used by the City and caused a major slowdown of the City's email network for about a day on February 25, 2002.
The./test triggered a weakness in the version of Lotus Domino software used by the City and caused a major slowdown of the City's network for about a day on March 22, 2002.
I've been experimenting with this type of use at home. I've use both a Panasonic CF-01 and a Fujitsu Stylist 1200, using 802.11b. They are hooked into one of my machines that has a DSL connection. Having wireless web surfing was my prime reason. A few issues that I've experienced:
Battery life - 802.11b pcmcia cards seem to suck the lifeblood out of batteries. They really drain dry within an hour or two. They also generate a large amount of heat.
Screen Size - 800x600 would be the bare minimum for surfing. Anything less really is sub optimal on the user experience.
Keyboard input - In my opinion, this is a huge limitation. No keyboard means using sometype of onscreen keyboards, which really sucks. It's painful to type sentences by tapping on the screen and the "writing" recognition just isn't there yet. The killer app for these wireless handhelds will be someone coming up with a easy and RELIABLE way of entering textual data.
Can somebody explain the insanity of the mod system on/.? In the span of 16 hours, my initial post on this subject went from (5 insightful) to (4 Troll)... I don't see how folks can assume I'm trolling...
My 4 year old daughter was spun up due to all the Christmas excitement. We were having trouble getting her to sleep until we showed her where santa was on the map - he's getting close! So off to bed she went without a peep.
One thing that wasn't noted in the article - how sturdy is it? You fold/bend/crinkle paper and it still can be read. How well will this hold up when it ends up in the hands of the lowest common denominators?
Re:Wasn't this similar to the scam a while back?
on
Personal Helicopter
·
· Score: 2
Rocket Belt was Hydrongen Peroxide Powered and most famous - built by Bell Textron. Flight duration of about 20 seconds or so, that's what flew in the LA Olympics and the Michael Jackson Concerts and In thunderball, etc.
The Jet Pack was a different animal all together. Strap a cruise missile engine to your back, encase the turbine with JP-8 (or whatever they had then). Didn't last long, but it did lead to the development of the WASP.
http://www.shreve.net/~jnuts/fly/old/wasp.html
I hope the glass is half full on this one, but it will probably be empty instead.
It's a great theory, one that's been tried time and time again. The Hiller flying platform being one of the first and most recognizable:
http://www.shreve.net/~jnuts/fly/hiller.htm
Lots of other folks have built upon a similar theme, most with multiple engines, some with ducts, some without, but ALL of them have a larger duct area or rotor span. I just don't think they'll get the thrust, much less handle the control problems.
for some more examples (that are flying):
http://www.flying-platform.com/
http://www.vtol.co.il/page1.html
http://www.shreve.net/~jnuts/fly/old/helivector.ht ml
As others have said, this judgement will obviously appealed. In the interim, before the appeal works it's way through the system, will this precedent have any affect on other software issues that are or are about to be brought to court?
Slashdot Mirror
I've tried various distros over the years, but none had enough polish for the rest of my family to use.
After installing the distro on a lower end machine (PII 350), I took the plunge and migrated my wife's machine.
She loves the eye-candy in Gnome. All she does is surf, email and use office apps. I upgraded to Open Office 2 and she's happy.
Past attempts at migrating my wife's machine to a distro failed. This one worked great.
My kid's machines are next.....
User support on the Ubuntu forums has been great. Any problems I run into usually can be answered with a search of the forums.
Where was the pre-install testing?
A good test should have identified some errors, especially if it blew up IMMEDIATELY.
we'll Slashdot their mail room....
Nah.... how about their server...
http://www.sco.com/support/linux_info.html
SCO seems like a drunken idiot, getting deeper and deeper into a disease. How irrational can the get?
Here are some links to help out with gps:
(nothing to cosmic, I just did a google search)
Nulling Antennas:
Navy
Mayflower
Owego
How GPS Works
Info about L1, L2, p-code, etc
Some info on GPS NMEA sentences
-jim
Jamming a GPS signal is not that hard - the amount of energy received by the antenna is minimal and can easily be jammed by a source on the ground. Anti-jamming GPS antennas detect jamming and "null" out the signal for that quadrant - just think of an antenna as a pie, all sliced up - if one segment is jammed, that slice of pie's information is discarded until the jamming goes away. The amount of satellites you recieve on your omni-directional GPS antenna will probably be lowered, but at least your signal won't disappear completely. (I don't have the links handy that explain this better)
"Spoofing" the signal is much more difficult and is damn near impossible..(at least we think...) for a GPS that is getting signals from the satellite constellation. The only true way to spoof a GPS reciever would be to bring it into a closed room and set up a simulated constellation for the reciever to lock on to. Some universities have done this type of research in an effort to provide robots with a sense of location.
The GPS string that is sent out by the reciever is defined by standards and is in plain text. The RMC, GGA, VTG sentences that are output are enough to give location, altitude, ground speed, etc. To simulate actual reception, all you have to do is playback a recorded text file of a previous reception. Heck, you wouldn't even need to use a recorded file - just make a script/program to spit the data out over the com/usb port. Hence, for this to be secure... The link from the GPS to the crypto black box had better be encrypted... But then how secure is that encryption? If this was a military only device where encryption is relied upon using their crypto devices and keytapes...then this thing could be robust. Once out into the civilian sector, they won't have the same level of encryption.
What happens if I've got two conference rooms in the same building, both needing access, but both belonging to a different company? Will both companies look the same w/regards to GPS crypto?
What's the "threshold" that the GPS system will accept as being "close enough"? Here's something to try...this assumes a GPS without the secret crypto keys loaded to get the "best" position. Start up a gps and keep logging the position that it thinks its at. This position will change ever so slightly over time. Reboot the GPS, compare the position on reboot...it will be a little bit different...(depending on how precise you want those co-ordinates)
My point is that there will have to be some "slop" allowed...some noise level that will need to be allowed into the system.
These are the things that could be used to exploit it.
-jim
for a better link...
./test triggered a weakness in the version of Lotus Domino software used by the City and caused a major slowdown of the City's network for about a day on March 22, 2002.
The email test triggered a weakness in the version of Lotus Domino software used by the City and caused a major slowdown of the City's email network for about a day on February 25, 2002.
The
-jim
I've been experimenting with this type of use at home. I've use both a Panasonic CF-01 and a Fujitsu Stylist 1200, using 802.11b. They are hooked into one of my machines that has a DSL connection. Having wireless web surfing was my prime reason. A few issues that I've experienced:
Battery life - 802.11b pcmcia cards seem to suck the lifeblood out of batteries. They really drain dry within an hour or two. They also generate a large amount of heat.
Screen Size - 800x600 would be the bare minimum for surfing. Anything less really is sub optimal on the user experience.
Keyboard input - In my opinion, this is a huge limitation. No keyboard means using sometype of onscreen keyboards, which really sucks. It's painful to type sentences by tapping on the screen and the "writing" recognition just isn't there yet. The killer app for these wireless handhelds will be someone coming up with a easy and RELIABLE way of entering textual data.
-jim
Can somebody explain the insanity of the mod system on /.? In the span of 16 hours, my initial post on this subject went from (5 insightful) to (4 Troll)... I don't see how folks can assume I'm trolling...
There be some warped minds out there...
My 4 year old daughter was spun up due to all the Christmas excitement. We were having trouble getting her to sleep until we showed her where santa was on the map - he's getting close! So off to bed she went without a peep.
One thing that wasn't noted in the article - how sturdy is it? You fold/bend/crinkle paper and it still can be read. How well will this hold up when it ends up in the hands of the lowest common denominators?
Rocket Belt was Hydrongen Peroxide Powered and most famous - built by Bell Textron. Flight duration of about 20 seconds or so, that's what flew in the LA Olympics and the Michael Jackson Concerts and In thunderball, etc.
The Jet Pack was a different animal all together. Strap a cruise missile engine to your back, encase the turbine with JP-8 (or whatever they had then). Didn't last long, but it did lead to the development of the WASP.
http://www.shreve.net/~jnuts/fly/old/wasp.html
I hope the glass is half full on this one, but it will probably be empty instead. It's a great theory, one that's been tried time and time again. The Hiller flying platform being one of the first and most recognizable: http://www.shreve.net/~jnuts/fly/hiller.htm Lots of other folks have built upon a similar theme, most with multiple engines, some with ducts, some without, but ALL of them have a larger duct area or rotor span. I just don't think they'll get the thrust, much less handle the control problems. for some more examples (that are flying): http://www.flying-platform.com/ http://www.vtol.co.il/page1.html http://www.shreve.net/~jnuts/fly/old/helivector.ht ml
As others have said, this judgement will obviously appealed. In the interim, before the appeal works it's way through the system, will this precedent have any affect on other software issues that are or are about to be brought to court?