[time-nuts] More GPS troubles

[Jim Lux]

On 1/17/13 6:22 AM, Bob Camp wrote:
> Hi
>
> Most cheap GPS's these days have user friendly firmware update capability.
> That's been true for quite a while. I'd be amazed if the higher end stuff
> didn't make updates an easy thing. Bugs in GPS code are not exactly
> uncommon.
>
> The real issue is the need to get the GPS code patched for this kind of
> thing. Without nutty articles that alarm the marketing department, the work
> will never get any sort of priority.

But is there *really* a need to patch for this..(as opposed to the other 
bugs that are on the list)

Consider you're using GPS as a time reference in a "mission critical" 
application.  You've already got to have some holdover capability.  Do 
you think someone could set up one of these jammers, jam your GPS, and 
keep doing it for long enough to extend you past your max holdover time?
If you're that critical, you need geographically dispersed receivers 
anyway (struck by lightning?)

In the example of the high accuracy reference networks.. they're 
*networks* and they are designed so that individual nodes can fail. 
Spoofing attacks, by their nature, can really only attack one receiver 
at a time even if the spoof signal covers a long distance(because only 
for the chosen victim do all the signals line up just right). So now 
you're talking about N jammers for N receivers, and the cost of your 
jamming attack is rising.

Someone who wanted to deny the use of the network would be better served 
by sending someone out with aluminum foil/paint to cover the radome of 
the stations. Or a cutting torch and sawzall. (tougher to do and a bit 
more obvious than commanding an array of jamming systems from your 
underground lair)