On Sun, Nov 15, 2009 at 07:41:35PM -0500, Mike Monett wrote:
One can clearly divide the targets into soft ones (GPS timing,
AVR systems, some civilian aircraft nav, civilian vehicle nav etc) and
some very hard ones (multiple frequency steered beam antenna military
P/Y keyed systems which can take advantage of all the known tricks).
Presumably there is now quite a bit of experience in the
military with jamming their jam resistant systems (or trying to and
failing) and presumably they have some well thought out strategies for
neutralizing it or its impact... for them.
However, there are many SOFT users who actually depend on GPS
more than they realize who have gear that can be knocked out by weak
jamming (as illustrated by interference cases from innocent sources like
malfunctioning antenna preamps) very easily. Not clear to me what the
effects of doing so over a wide area might be now or especially in 5-10
years from now when more and more stuff depends on GPS timing or
location or frequency or all three.
Civilian gear does not in general worry about jamming... and
its operators rarely have the training or access to the reason it may
not be functioning to know that jamming is happening. This is
especially true of spoof jamming that attempts to create false timing or
position as opposed to jamming that just causes an effective no GPS
condition.
John is right, that jamming that knocks out service or causes to
be wrong intermittently would be just as effective in many cases as
steady blanket jamming... especially if there is little expectation that
this might be a threat. (Clearly the military has considered all this
carefully, but not necessarily for the civilian uses they may not even
know about).
And while restoring a destroyed Loran C site might take a while,
launching a new GPS satellite to replace one destroyed by some natural
event (solar outbursts) or some man made event (clouds of debris - either
deliberate or accidental) takes MUCH longer and cannot be hurried up much.
I doubt many flight ready spares are kept around (including rocket and
all the rest) and even if there are one or two a major event could take
out more than that number if it is at all global in impact.
--
Dave Emery N1PRE/AE, die@dieconsulting.com DIE Consulting, Weston, Mass 02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in
celebration of what could have been, but wasn't and is not to be now either."
On Sun, Nov 15, 2009 at 07:41:35PM -0500, Mike Monett wrote:
One can clearly divide the targets into soft ones (GPS timing,
AVR systems, some civilian aircraft nav, civilian vehicle nav etc) and
some very hard ones (multiple frequency steered beam antenna military
P/Y keyed systems which can take advantage of all the known tricks).
Presumably there is now quite a bit of experience in the
military with jamming their jam resistant systems (or trying to and
failing) and presumably they have some well thought out strategies for
neutralizing it or its impact... for them.
However, there are many SOFT users who actually depend on GPS
more than they realize who have gear that can be knocked out by weak
jamming (as illustrated by interference cases from innocent sources like
malfunctioning antenna preamps) very easily. Not clear to me what the
effects of doing so over a wide area might be now or especially in 5-10
years from now when more and more stuff depends on GPS timing or
location or frequency or all three.
Civilian gear does not in general worry about jamming... and
its operators rarely have the training or access to the reason it may
not be functioning to know that jamming is happening. This is
especially true of spoof jamming that attempts to create false timing or
position as opposed to jamming that just causes an effective no GPS
condition.
John is right, that jamming that knocks out service or causes to
be wrong intermittently would be just as effective in many cases as
steady blanket jamming... especially if there is little expectation that
this might be a threat. (Clearly the military has considered all this
carefully, but not necessarily for the civilian uses they may not even
know about).
And while restoring a destroyed Loran C site might take a while,
launching a new GPS satellite to replace one destroyed by some natural
event (solar outbursts) or some man made event (clouds of debris - either
deliberate or accidental) takes MUCH longer and cannot be hurried up much.
I doubt many flight ready spares are kept around (including rocket and
all the rest) and even if there are one or two a major event could take
out more than that number if it is at all global in impact.
--
Dave Emery N1PRE/AE, die@dieconsulting.com DIE Consulting, Weston, Mass 02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in
celebration of what could have been, but wasn't and is not to be now either."
