[time-nuts] sub-minute time-precision in court-case

Jim Lux jimlux at earthlink.net
Wed Sep 4 00:07:47 UTC 2013


On 9/3/13 2:47 PM, Tom Van Baak wrote:
>> Nowhere does the opinion mention if the timestamps were taken on
>> the same clock or if the two clocks were synchronized.
>
> PHK,
>
> Correct. This is an age-old problem, whether its minutes or
> nanoseconds. Time-stamps are inherently relative to a local
> oscillator's time and rate offset, and affected by frequency drift
> and stability levels.
>
> A solution to this problem is for the "first responder" to take the
> cell phone(s) and simultaneously send a text message to himself from
> each phone. That could help establish a legal time difference
> (unless, there are variable reception or carrier-specific delays).

No way is the FR going to do anything with that phone other than drop it 
into a shielded bag, maybe after removing the battery.

Operating the keys on the phone would be "tampering with the evidence".

>
> They could also simultaneously send cell phone photos of a handheld
> GPS receiver's time display. That could help establish a legal time
> accuracy question (unless, the cell phone or GPS receiver were in
> some sort of hold-over mode).

If that's the case, it would be done in a forensic lab with the phone 
hooked up to one of those fancy phone analysis systems.

>
> For extra credit, further photos can be sent each hour for hours or
> days to determine the cell phone frequency drift and stability
> parameters.
>
> Then again, realize that a jury of your fellow citizens, not a jury
> of your "peers", will decide the question of timing. Thus to raise
> technical issues like syntonization vs. synchronization, or standard
> vs. Allan deviation, or GPS vs. UTC clocks will probably not help
> your case.

There's a whole literature of mystery novels based on timetables and 
such, including clever use of that new fangled device the telephone to 
make someone think they are in one place rather than another.

WHen *I* commit that perfect murder, and am unhappily arrested, I'm 
going to demand that only time-nuts sit on the jury.  You've been 
warned.  The Ventura county courthouse is in a fairly pleasant location 
near the shore and has a decent cafeteria.  Pray I do not get arrested 
in Los Angeles county, which is a hellhole in which to serve as a jury 
member.


Realistically, though, there's a lot of potential time related 
litigation in the securities industry.  Accusations of "front running" 
in the high frequency trading area, for instance, might revolve around 
milliseconds.


For all we know, there are litigation consultants reviewing the archives 
of this list at this very moment, identifying people who they would or 
would not want sitting on the jury.



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