[time-nuts] lightsquared test in las vegas

Bob Camp lists at rtty.us
Thu Jun 9 16:17:04 EDT 2011


Hi

Ummm, errr ... not so much.

KAL007 went down September 7th 1983. NIST was publishing papers on two way
time transfer in 1980:

http://tf.nist.gov/general/pdf/192.pdf

Much of the early GPS timing and design work was made quite public in
various FCS papers in the 1970's.

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Brooke Clarke
Sent: Thursday, June 09, 2011 1:28 PM
To: jfor at quik.com; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] lightsquared test in las vegas

Hi John:

It's my understanding the the GPS system was designed by the military so 
that the received signal is below the thermal noise.  That means that if 
you look for it with a spectrum analyzer you will see noise.  It wasn't 
untill the KAL007 shoot down that the goverment disclosed it's existence 
to prevent a similar thing from happening.  The new GPS L5 "Safety of 
Life" signal is to make aviation safer.  So it appears that the focus 
has changed from military to aviation.
http://en.wikipedia.org/wiki/Korean_Air_Lines_Flight_007#Aftermath
http://www.prc68.com/I/DAGR.shtml#GPSs

Have Fun,

Brooke Clarke
http://www.PRC68.com


J. Forster wrote:
> Perhaps not in the abstract, but on-orbit power is severely limited, and
> you can't get more RF watts out of a transmitter than you put in as DC.
>
> Can you imagine the uproar if every GPS bird had a 10 KW transmitter on
> board, powered bu a nuclear reactor?
>
> The low received power is a direct consequence of engineering of
satellites.
>
> -John
>
> ================
>
>
>
>    
>> On the other hand, what can be said about the wisdom of engineers that
>> designed a product that cannot withstand any interference from adjoining
>> spectrum holders?  It has been known for at least the last 6 years that
>> LightSquared's predecessor was going to occupy that spectrum with a land
>> based system.
>>
>> Does the GPS world really have much to say about the interference if
>> LightSquared keeps their transmitters clean and out of the GPS spectrum?
>>
>> -Chuck Harris
>>      
>
>
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