[ntp:questions] how to have offset < 1ms

unruh unruh at wormhole.physics.ubc.ca
Wed Apr 14 23:46:48 UTC 2010

On 2010-04-14, John Hasler <jhasler at newsguy.com> wrote:
> nemo_outis writes:
>> Given the lack of stroke of the OP and/or the recalcitrance of the
>> ship's management, what is the likelihood that, having rejected
>> something as simple as using a GPS receiver (which is likely *already*
>> available on any modern oceanographic ship)...
> As someone else pointed out (and a bit of research confirms) it is not
>  likely that the GPS on the bridge provides time in any usable form[1].
>> ...that they would approve the OP's "dicking" with the network, a
>> process which is far more likely to be disruptive?
> While the ship's officers are probably very protective of the equipment
> on their bridge and hostile to the idea of mounting antennas and
> drilling holes anywhere on the ship, they may be barely aware of the
> existence of the LAN and couldn't care less what the geeks do with it
> (as long as they drill no holes).  After all, it does nothing important
> (i.e., steer the ship or control the engines).

He could always hang a gps antenna out a porthole. That gives him a 180
degree sight of the sky, which should be pleanty (I have my antenna on
the front portch of my house with the house covering more than half the
sky, and a bunch of huge trees rising to 45 degrees in the sky from the
gps. And it works find for timekeeping. 
The gps18 has a strong magnet on its base so it would stick to ship
easily. Of course the computer room might be in the bowels of the ship,
in the engine room or something, with no view of anything and no
portholes. etc. But we do not know. 

> [1]  A bit of Googling indicates that the major players are trying to
> lock ships into proprietary networks for bridge electronics.

More information about the questions mailing list