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Interesting overview of GPS status and prospects, with recommendations:



http://www.acq.osd.mil/dsb/reports/2005 ... _Final.pdf

Defense Science Board Task Force
on
The Future of the Global Positioning System

October 2005
Office of the Under Secretary of Defense
For Acquisition, Technology, and Logistics
Washington, D.C. 20301-3140

[109 PDF pages]

Interesting. The military seem to struggle with jamming. What hope is
there for civilan users?

Can we have systems critically dependent on GPS / Galileo with the
associated risk of jamming?

"Alex Terrell" <alexterrell@yahoo.com> wrote in message
news:1133307634.018870.254690@g43g2000cwa.googlegroups.com...

Interesting. The military seem to struggle with jamming. What hope is
there for civilan users?

Can we have systems critically dependent on GPS / Galileo with the
associated risk of jamming?

Do you live where you epect that to be a problem? And where jamming is
likely, I think critically dependent civilian systems (if any) are going to
have more serious problems.

"David L. Wilson" <dwilson314@adelphia.net> wrote:

"Alex Terrell" <alexterrell@yahoo.com> wrote in message
news:1133307634.018870.254690@g43g2000cwa.googlegroups.com...
Interesting. The military seem to struggle with jamming. What hope is
there for civilan users?

Can we have systems critically dependent on GPS / Galileo with the
associated risk of jamming?

Do you live where you epect that to be a problem? And where jamming is
likely, I think critically dependent civilian systems (if any) are going to
have more serious problems.

If any? There's already at least one - aircraft autolanding systems.

D.
--
Touch-twice life. Eat. Drink. Laugh.

-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL

On Wed, 30 Nov 2005 07:30:52 -0500, "David L. Wilson" <dwilson314@adelphia.net>
wrote:

I do not mean to say that jamming is not a problem for the civiilian
community but in the scale of things, there are more serious problems in a
conflict area. Of course if for some reason jammers became prevalent in
non-hostility areas, that would be a different matter.

A good "war story" of civilian jamming here:

http://www.gpsworld.com/gpsworld/articl ... &&pageID=1

"Derek Lyons" <fairwater@gmail.com> wrote in message
news:43924748.19357002@news.supernews.com...

"David L. Wilson" <dwilson314@adelphia.net> wrote:

"Alex Terrell" <alexterrell@yahoo.com> wrote in message
news:1133307634.018870.254690@g43g2000cwa.googlegroups.com...
Interesting. The military seem to struggle with jamming. What hope is
there for civilan users?

Can we have systems critically dependent on GPS / Galileo with the
associated risk of jamming?

Do you live where you epect that to be a problem? And where jamming is
likely, I think critically dependent civilian systems (if any) are going
to
have more serious problems.

If any? There's already at least one - aircraft autolanding systems.

And then the more serious problems in the area becomes the main part of my
post.
I do not mean to say that jamming is not a problem for the civiilian
community but in the scale of things, there are more serious problems in a
conflict area. Of course if for some reason jammers became prevalent in
non-hostility areas, that would be a different matter.

On Wed, 30 Nov 2005 14:13:11 +0000, Marc Brett wrote:

A good "war story" of civilian jamming here:

http://www.gpsworld.com/gpsworld/articl ... &&pageID=1

Thanks, very interesting! I found this paragraph telling:

"Source-1 had the highest level at -96 dBm. Its location is
known to have been 325 meters from the MBARI antenna. It was at
an elevation angle of -2.5 degrees. While the beam pattern of
Source-1 is unknown, if it were omni-directional, it would
exceed this FAA specification at a range of 50 kilometers or
more. It is known to have caused marine GPS receivers to lose
lock out to 3 kilometers. The effective power of this source can
only be bounded from the data available. It is at least a few
milli-watts."

It indicates that a transmitter with a few milliwatts is capable
of jamming GPS receivers within 3 km.

Hans-Georg

--
No mail, please.

David L. Wilson wrote:

"Alex Terrell" <alexterrell@yahoo.com> wrote in message
news:1133307634.018870.254690@g43g2000cwa.googlegroups.com...
Interesting. The military seem to struggle with jamming. What hope is
there for civilan users?

Can we have systems critically dependent on GPS / Galileo with the
associated risk of jamming?

Do you live where you epect that to be a problem? And where jamming is
likely, I think critically dependent civilian systems (if any) are going to
have more serious problems.

Jamming is likely where critically dependent civilian system will
exist. At present, these applications are somewhat limited, but in
future that may not be the case.

Germany already has a lorry tolling scheme whose performance (and hence
revenue) is partly dependent on GPS performance. If this sort of scheme
extends to cars it will become a target.

Today I saw a 1mW GPS jammer that can disable GPS for upto 100m. This
low power would be exceedingly difficult to locate.

"Alex Terrell" <alexterrell@yahoo.com> wrote:

Interesting. The military seem to struggle with jamming. What hope is
there for civilan users?

Can we have systems critically dependent on GPS / Galileo with the
associated risk of jamming?

You are getting two new frequencies (L2C and L5) which provide
spectral redundancy.

Systems that use GPS for critical applications should have redundant
systems in the event that GPS cannot provide the required service.

Ron Lee

Alex Terrell wrote:

David L. Wilson wrote:

"Alex Terrell" <alexterrell@yahoo.com> wrote in message
news:1133307634.018870.254690@g43g2000cwa.googlegroups.com...

Interesting. The military seem to struggle with jamming. What hope is
there for civilan users?

Can we have systems critically dependent on GPS / Galileo with the
associated risk of jamming?

Do you live where you epect that to be a problem? And where jamming is
likely, I think critically dependent civilian systems (if any) are going to
have more serious problems.


Jamming is likely where critically dependent civilian system will
exist. At present, these applications are somewhat limited, but in
future that may not be the case.

Germany already has a lorry tolling scheme whose performance (and hence
revenue) is partly dependent on GPS performance. If this sort of scheme
extends to cars it will become a target.

Oregon is testing a system where the gas tax is based on miles driven
rather than gas consumption. This is presumably to encourge gas guzzlers
and discourage foreign fuel efficient cars like a hybrid.

Any to get back to the point. It uses a GPS to determine when you leave
the state so that it won't charge tax on miles driven outside the state
although it would charge tax on gas purchased outside the state I
suppose since it reads the mileage the next time you gas up. I am not
sure how it handles this. Anyway, if it were jammed you would pay more
taxes.

Dale
--
_ _ Dale DePriest
/`) _ // http://users.cwnet.com/dalede
o/_/ (_(_X_(` For GPS and GPS/PDAs

In article <s1pro1lgs37cuafgd7o4113cikh33n9t79@4ax.com>,
Hans-Georg Michna <hans-georgNoEmailPlease@michna.com> wrote:

It indicates that a transmitter with a few milliwatts is capable
of jamming GPS receivers within 3 km.

Yes, the GPS signals are *very* faint -- actually below the noise floor,
unless you look for them with digital signal processing techniques like
those of GPS receivers -- and jamming them is unpleasantly easy.
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. | henry@spsystems.net

Alex Terrell wrote:
%< Snip

Germany already has a lorry tolling scheme whose performance (and hence
revenue) is partly dependent on GPS performance. If this sort of scheme
extends to cars it will become a target.

And the British Government has just announced a programme to move to a
road taxation system based both on distance covered and time of day
('congestion charging') that is said to be planned to use GPS
technology.

Peter
-----------------------------------------------------------------------

Dale DePriest <Dale@gpsinformation.het> wrote:

:Oregon is testing a system where the gas tax is based on miles driven
:rather than gas consumption. This is presumably to encourge gas guzzlers
:and discourage foreign fuel efficient cars like a hybrid.

So folks from out of state don't pay gas taxes?

:Any to get back to the point. It uses a GPS to determine when you leave
:the state so that it won't charge tax on miles driven outside the state
:although it would charge tax on gas purchased outside the state I
:suppose since it reads the mileage the next time you gas up. I am not
:sure how it handles this. Anyway, if it were jammed you would pay more
:taxes.

So they're coming up with a system that requires several hundred
dollars (at least) worth of hardware on each vehicle and EVERY gas
pump to be modified to collect?

This seems just slightly nuts. Cite?

--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

Fred J. McCall wrote:

Dale DePriest <Dale@gpsinformation.het> wrote:

:Oregon is testing a system where the gas tax is based on miles driven
:rather than gas consumption. This is presumably to encourge gas guzzlers
:and discourage foreign fuel efficient cars like a hybrid.

So folks from out of state don't pay gas taxes?

:Any to get back to the point. It uses a GPS to determine when you leave
:the state so that it won't charge tax on miles driven outside the state
:although it would charge tax on gas purchased outside the state I
:suppose since it reads the mileage the next time you gas up. I am not
:sure how it handles this. Anyway, if it were jammed you would pay more
:taxes.

So they're coming up with a system that requires several hundred
dollars (at least) worth of hardware on each vehicle and EVERY gas
pump to be modified to collect?

This seems just slightly nuts. Cite?

I agree as do several other people

http://economics.about.com/od/taxesande ... ge_tax.htm

Dale
--
_ _ Dale DePriest
/`) _ // http://users.cwnet.com/dalede
o/_/ (_(_X_(` For GPS and GPS/PDAs