Quote:
Originally Posted by Don Rotolo
Doppler isn't working on signal strength, but the doppler frequency shift caused by the (electronic) rotation of the antennas. In order to have a detectable frequency shift, the antennas need to be "rotated" very quickly. More antennas means more switch 'changes' per second, less time to capture and process the doppler-shifted signal, and the design and performance burdens associated with having to do all this faster and with less signal.
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That is really cool.
The system I looked at worked a little differently. I know I'll mangle it, so please be patient
. As I understood it, the system had N omni-directional antennae, and measured the relative phase between any two antennae. This created N^2-N virtual pseudo-directional antennae. Each of these virtual elements could tell you what direction it was relative to the line that passed between its corresponding real antennae, but had a couple of faults: Its accuracy was a function of direction, and it couldn't tell front from back from top to bottom - it carved out a fuzzy hollow cone. With enough of these fuzzy hollow cones, the original direction could be teased out.
With that type of setup (aka money is no object), more does equal better. I can see why with the other set-up (wicked sweet), more equals more complicated. Science is awesome.
This virtually spinning doppler thing looks really neat, I'm going to have to check it out! Thanks for the info