Real time active aiming?( was Re: [Laser] Laser comm stuff)
Derek Weston
[email protected]
Wed, 23 Jul 2003 08:44:38 +1000
John Dalton wrote:
>
> > And another way is to work with uStepper motors..
>
> Closely related, is anyone doing any work on actively
> aiming a laser tx and rx at each other? I asked this
> at least a year ago and there was no positive response.
>
> Ideally I'm talking active to the point of being able
> to compensate for vibration of the mounting points.
>
> I've been putting lots of thought into this myself, but
> have yet to come up with a reasonanbly priced,
> easy to construct, solution that I think will work.
>
> John
There are two aspects to this problem, the mechanical (or whatever)
means to steer the beam and the basis on which you perform the steering
process.
The mechanical aspects have been adequately covered by others from time
to time on the laser list.
The control system which drives the steering system has not (as far as I
recollect) been discussed on the list. The only fully automatic means I
can imagine being effective is described in a paper by Matthew Astley.
Basically each laser sends data packets while scanning in the general
direction of the target. Each packet includes the coordinates of the
steering system at which that packet was sent, and if a similar packet
has been heard from the other end the coordinates of the other steering
system in the packet received. Eventually the aligned coords at both
ends are known by both ends and the beams can be aligned therefrom.
Matthews site is down at present but you can get a copy from Google's
cache. Google "Protocol for self-alignment of laser-through-air ethernet
links"
I doubt this could be made to work for vibration, but for auto alignment
it seems to me to be the only possible method without using other links
between the ends which are independent of the laser link.