On Sun, 21 Dec 2003 21:00:20 +0000, phil hunt wrote:
On Sat, 20 Dec 2003 12:34:10 -0800, pervect wrote:
On Sat, 20 Dec 2003 18:15:56 +0000, ess (phil
hunt) wrote:
If you don't go to spread-spectrum, your radio links will probably be
jammed. (Solution - go to spread spectrum).

Indeed.

Then you need to use relatively high frequencies, and your
radio navigation system will be line-of-sight only.

This then means you need lots of closely-spaced transmitters,
especially if you want to be able to navigate while flying
at low altitude.

I'd still rate a radio location system using spread spectrum
transmitters as rather vulnerable, because the transmitters have to
remain in a fixed location for the system to work, and would be prime
targets.

What if most of the transimtters are turned off most of the time? If
there are fake transmitters, there to soak up hits, and (hopefully)
entice enemy aircraft to put themselves in danger?

Then your radio navigation system has gotten a lot more
complicated. You can't just set up transmitters at arbitrary
locations broadcasting at arbitrary times -- to work, a radio
navigation system needs known transmitters at precisely known
locations.

Say 80 percent of your transmitters are turned off at any one
time. Then you need five times as many transmitters in total,
so that you can get complete coverage in the area where you want
to navigate with only 20 percent of them.

If you set up fake transmitters to attract attention away from
the real ones, you also need to somehow avoid spoofing your own
weapons. It would kind of suck if all of your HLCCMs flew off
to the wrong place because they were navigating using signals
from a fake transmitter.


ljd