[time-nuts] Timing Distribution in Mountainous Terrain

[Ralph Smith]

On Thu, September 9, 2010 1:10 pm, Matthew Kaufman wrote:
>   On 9/9/2010 8:37 AM, Ralph Smith wrote:
>> We have a requirement for approximately ten radio sites to be
>> synchronized
>> to within 30 ns of each other.
> 30 ns seems a little closer than most radio site applications need...
> what drives this requirement?

Aircraft surveillance using multilateration.

>> Ordinarily you could throw in an
>> appropriate GPSDO and be done with it. However, we also have the
>> reqirement to be able to operate independent of GPS for up to six days.
> Wow, ok, and what drives *that* requirement? Can you use any other

Paranoia. People making the requirements are concerned with GPS going away
due to solar flare or some other reason.

> mutually visible thing, or do we assume all satellites have vanished
> from orbit?

No satellites.

Thanks,
Ralph