[time-nuts] Timing Distribution in Mountainous Terrain

[J. L. Trantham, M. D.]

I guess I am thinking about this from a user perspective rather than an
engineering design and implementation perspective.  If the requirement is
aircraft separation, LORAN should be adequate for that, if it was still up.
You would only have to transmit your position and altitude to a ground
receiving station that then would relay it to the Center Controllers to be
displayed on a map along with all the other aircraft.

However, it seems they want to do this by use of an upside down but
otherwise 'GPS like method', i.e., the 'satellites' are fixed to
mountaintops and the aircraft still moves.

That being the case, what about a fixed, land-line, connection for every
mountaintop to a central location that broadcasts the time signal, calibrate
the system using GPS then rely on the central ground station to keep it
running?

Joe

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
Behalf Of Oz-in-DFW
Sent: Friday, September 10, 2010 12:21 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Timing Distribution in Mountainous Terrain


On 9/10/2010 7:26 AM, Ralph Smith wrote:
> On Sep 10, 2010, at 7:50 AM, J. L. Trantham wrote:
>
>> Loran was used as an area navigation method in aviation for many years.
It
>> was available nation wide with a number of chains.  I had assumed that
the
>> area of interest was the Rocky's but if the Appalachians, even better.
> The site currently under consideration is in Colorado. Only problem with
Loran, of course, is that is has been killed, thus the operative word "was"
above. If the design and approach bears out it could be deployed over a much
wider scale.
>
> Ralph
Even if LORAN was alive it wouldn't meet the requirement.  You'd still
have 20-30 M position uncertainty in a differental application - way
more than your 30 ns.   I thiink that dropping LORAN was a really big
mistake, but it wouldn't meet this need.   I used to see several 100 ns
of time drift and jitter when I was in San Antonio and watching Boise
City, OK (~600 Mi)

--
mailto:oz at ozindfw.net
Oz
POB 93167
Southlake, TX 76092 (Near DFW Airport)





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