It seems to me that GPS has been oversold as the be all, end all system
that made all other systems obsolete and GPS has become all but an
indespensible utility.

Reports like this, could well be used to promote a backup, like LORAN or
eLORAN, just as public buildings have backup generators.

YMMV,

-John

==================

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

Yes GPS is/was oversold.

Trouble is Clarkes law applies here (any sufficiently advanced technology is indistinguishable from magic).  And this applies double to the technological illiterates in DC

See Sen 'Tubes' Stevens for the canonical example

Sent from my iPhone

On Jul 29, 2013, at 12:46 PM, "J. Forster" jfor@quikus.com wrote:

I think the largest concern about jamming is for civilian uses, rather
than military, mainly because military receivers are designed and built to
be more immune. Also, military systems are far more likely to have good
grade INS.

Furthermore, there are probably a couple of orders of magnitude more
civilian systems in use.

-John

==================

It is easy to jam a simple GPS receiver.  Harder to jam a military
receiver.  In a conflict a jammer of any kind is pretty much a beacon that
says "here I am".  It is one of the bigger problems of jamming, you have to
radiate RF.  So either you have to be very close to your target or have a
powerful jammer.

Simple civilian jammers are easy, like the one a truck driver might use to
prevent his boss from tracking him, It only has to cover a few feet.    But
try and jam a jet flying at 40,000 feet or a navel carrier task force.

On Tue, Jul 30, 2013 at 5:50 AM, Scott McGrath scmcgrath@gmail.com wrote:

--

Chris Albertson
Redondo Beach, California

The atmosphere protects the earth from a lot of stuff the universe throws at us

Solar flares , space junk , micrometeors just the usual hazards the space at large has.  Inability to service satellites when transmitters or RCS fuel exhausted

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On Jul 30, 2013, at 9:31 AM, "Lester Veenstra" lester@veenstras.com wrote:

If you read article the City of London basically has a GPS denial 10-15 minutes daily this covers a couple square miles

A lot of people are under the misconception that the spy shop jammers only do a few feet.  Reality is most of them are 100-500 mw and blank out at least a square mile

A suitcase sized unit at a high elevation could deny hundreds of square miles

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On Jul 30, 2013, at 11:52 AM, Chris Albertson albertson.chris@gmail.com wrote:

What does that have to do with "... based in LEO has a relatively high

I note the previous correction  to your statement, that it is MEO not LEO.

Lester B Veenstra  MØYCM K1YCM W8YCM
lester@veenstras.com

US Postal Address:
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GPS: 39.33675 N  78.9823527 W (Google)
GPS: 39.33682 N  78.9023741 W (GPSDO)

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This e-mail and any documents attached hereto contain confidential or
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-----Original Message-----
From: Scott McGrath [mailto:scmcgrath@gmail.com]
Sent: Tuesday, July 30, 2013 12:11 PM
To: lester@veenstras.com; Discussion of precise time and frequency measurement
Cc: jfor@quikus.com; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Story in the Economist about GPS jamming

The atmosphere protects the earth from a lot of stuff the universe throws at us

Solar flares , space junk , micrometeors just the usual hazards the space at large has.  Inability to service satellites when transmitters or RCS fuel exhausted

Sent from my iPhone

On Jul 30, 2013, at 9:31 AM, "Lester Veenstra" lester@veenstras.com wrote:

Yes. LOS jamming of the civilian code is easy; However whey do you think the
use of LEO aids this?

Lester B Veenstra  MØYCM K1YCM W8YCM
lester@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.

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@veenstras.com wrote: