Meteor Burst Communications (Score 1)

I'm not so impressed by this sonar thing, but some aspects reminded me of meteor burst communications, which is just cool:

High atmosphere ionization trails from micrometeors (of which there are a surprisingly large number every hour) alter the transmission properties of the atmosphere. Given two stations, you do some geometry, and then wait around for a suitable ionization event. When such an event occurs, transmissions will be symmetrically reflected between the two stations as long as the ionization trail has not dispersed too much.

This fact is exploited by broadcasting a pseudo-random (like a DS/SS chip) signal from a master station. When transmission sites that know the chip happen to pick up an ion-trail reflection of the master signal, then there exists for a short time a symmetric path back to the master, during which buffered data can be burst transmitted. If the trail lasts long enough, bi-directional communications may be possible. The system as a whole exhibits classic spread spectrum properties, including low probability of intercept, resistance to interference, and channel sharing.

Meteor burst communication is, however, very low bandwidth, but thats OK - most people using LPI communications aren't exactly streaming MP3s; you can get some pretty good milage with a few dozen bytes of text.

I don't know anything about the power requirements here... anybody have any usefull info, or corrections to my description? Its been a while since I've looked at this stuff.