Defense against UAV's

In article ,
says...
wrote:
Andrew Swallow wrote:
Jack Linthicum wrote:
[snip]

I think that a spread spectrum burst type transmission can be
intercepted and given a rough bearing. The money to do this is
miniscule in comparison with making Trident missiles into hand
grenades.
The command post does not move between transmissions. Spread
spectrum/frequency hopping systems return to previous frequencies every
few seconds. Just use several bursts to home in on the transmitter.
?? You transmit only when you want to issue new command to the swarm,
not to control every little thing. You can have minutes without
transmission, then 10ms transmission, followed by another long silence.


A machine can get a fairly accurate bearing in 10ms. Machines can be
made to be very patient so the several minutes is only a minor problem.
Several minutes allows wide angle receivers to be replaced by narrow
angle receivers sufficiently accurate to allow the targeting of weapons.


Narrow angle receivers require larger antennas or arrays of antennas.
Granted, that is easier at 900 Mhz than at 9Mhz.

Several minutes between hits on a narrowband frequency is different than
several hours---particularly if your platform is moving. Then you
get into problems with how accurately you know the position and
heading of the platform. Much more difficult than DF from a fixed
land base.
And you can also have plenty of cheap decoy trasmitters, just to make
it easier to intercept ... something. ;-)

Try brute force and ignorance - destroy the lot.
How many missiles will that take?


Mark Borgerson

Mark Borgerson wrote:
In article ,
says...
wrote:
Andrew Swallow wrote:
Jack Linthicum wrote:
[snip]

I think that a spread spectrum burst type transmission can be
intercepted and given a rough bearing. The money to do this is
miniscule in comparison with making Trident missiles into hand
grenades.
The command post does not move between transmissions. Spread
spectrum/frequency hopping systems return to previous frequencies every
few seconds. Just use several bursts to home in on the transmitter.
?? You transmit only when you want to issue new command to the swarm,
not to control every little thing. You can have minutes without
transmission, then 10ms transmission, followed by another long silence.

A machine can get a fairly accurate bearing in 10ms. Machines can be
made to be very patient so the several minutes is only a minor problem.
Several minutes allows wide angle receivers to be replaced by narrow
angle receivers sufficiently accurate to allow the targeting of weapons.


Narrow angle receivers require larger antennas or arrays of antennas.
Granted, that is easier at 900 Mhz than at 9Mhz.

Several minutes between hits on a narrowband frequency is different than
several hours---particularly if your platform is moving. Then you
get into problems with how accurately you know the position and
heading of the platform. Much more difficult than DF from a fixed
land base.

Mobile targets probably have to be attached by a plane that can chase them.

And you can also have plenty of cheap decoy trasmitters, just to make
it easier to intercept ... something. ;-)

Try brute force and ignorance - destroy the lot.
How many missiles will that take?

About 3 for every transmitter, depending on the accuracy of the DFing.
You will soon have a civilian population that is suspicious of decoy
transmitters.

Andrew Swallow