[time-nuts] Story in the Economist about GPS jamming

Lester Veenstra lester at veenstras.com
Tue Jul 30 15:12:57 EDT 2013


Well which is it:?

Question:  LOS jamming of the civilian code is easy; However why do you think the use of LEO [MEO] aids this?
Your response: "It doesn't"

Then you state:   " It" [ from context, the use of MEO orbit] "simply increases the risk that GPS will be made unavailable due to events outside the operators control"  

You cannot have it both ways. Either "it doesn't", or "it increases".  

Please be specific; In terms "Any competent engineer" would use, how does the choice of a LEO or MEO or even GEO orbit "simply increases the risk..." ?


Lester B Veenstra  MØYCM K1YCM W8YCM
lester at veenstras.com

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-----Original Message-----
From: Scott McGrath [mailto:scmcgrath at gmail.com] 
Sent: Tuesday, July 30, 2013 2:46 PM
To: lester at veenstras.com; Discussion of precise time and frequency measurement
Cc: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Story in the Economist about GPS jamming

It doesn't    It simply increases the risk that GPS will be made unavailable due to events outside the operators control    Hence system risk profile is high    

Was not so high when LORAN was available as aviation, maritime and timing applications could gracefully degrade to LORAN in the event GPS was unavailable

Now if GPS availability is denied we are back to maps bowdoins sextants and chronometers for navigation except for the vanishingly small number of ships and planes equipped with INS

Scott 


Sent from my iPhone

On Jul 30, 2013, at 1:28 PM, "Lester Veenstra" <lester at veenstras.com> wrote:

> Yes. LOS jamming of the civilian code is easy; However whey do you 
> think the use of LEO aids this?
> 
>>> Any competent engineer could have told the powers that be that a 
>>> satellite system based in LEO has a relatively high risk profile 
>>> from the Universe/hostile activity/spoofing and jamming
> 
> 
> Lester B Veenstra  M YCM K1YCM W8YCM
> lester at veenstras.com
> 
> US Postal Address:
> 5 Shrine Club Drive
> HC84 Box 89C
> Keyser WV 26726
> GPS: 39.33675 N  78.9823527 W (Google)
> GPS: 39.33682 N  78.9023741 W (GPSDO)
> 
> 
> Telephones:
> Home:                     +1-304-289-6057
> US cell                    +1-304-790-9192 
> UK cell                    +44-(0)7849-248-749 
> Guam Cell:              +1-671-929-8141
> Jamaica:                 +1-876-456-8898 
>  
> This e-mail and any documents attached hereto contain confidential or 
> privileged information. The information is intended to be for use only 
> by the individual or entity to whom they are addressed. If you are not 
> the intended recipient or the person responsible for delivering the 
> e-mail to the intended recipient, be aware that any disclosure, 
> copying, distribution or use of the contents of this e-mail or any 
> documents attached hereto is prohibited.
> 
> 
> 
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