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Video Wireless Plane Track System

Foreword:
The wireless video feed from a moving plane will be much improved in quality and range, if the receiver antenna is a directional type
and the direction is always pointing to the plane, a helper can do it for prof of concept,
The cool way is automaticly with motors and mecanics and electronics.

Different position methodes:
Several ways to find the direction to the plane exist:
GPS position for antenna and plane can be used, need one more data link from the plane, problems with height, motor system must always point north.
Multi Antenna RSSI, faster in lock, can be made with no jitter.
One Antenna RSSI, needs to jitter to find the best position.

Movement methodes:
The antenna needs to be able to move freely 180 degree up, and 360 degrees around.
the cable must not be twisted when flying arround the antenna, simple to solve with like pan/tilt movement system mounted sideways.


Motors/Servos:
Small antennas can be handled with big RC servoes, infact RC servoes exist today upto extreme sizes also, really big = expensive
DC motor and position feedback, can be made and scaled to ANY size, speed, and weight handling needed !


First try idea:
Two small RC servoes glued together, LDR resistor mounted on servo arm, with black tape 20mm length to make it directional,
LDR signal simulates RSSI signal from wireless receiver, so the software can be made and tested fast and easy.

First Hardware:
OSD board old version canbe used, Temp1 and Temp2 connector can drive two RC servoes,
any of the left 4 analog ports can be used to connect RSSI or LDR
Software functions:
The RSSI voltage levels must be able to adjust their trigger levels:
if RSSI is under x the system will stay in last good position, or go into slomo move mode ?
if RSSI is over x the system dont move, no need plenty of signal present, or go into slomo best signal anyway ?

Regulating Software loops:
two loops must be made, since I make the ONE antenna RSSI based system, only ONE rssi signal will tell the story about the signal
loop:
move motor 1, rssi stronger = move more, rssi weaker = change direction,
move motor 2, rssi stronger = move more, rssi weaker = change direction,
goto loop
some delays must be added, and some info about how much stronger or weaker the signals get can be used to set the move speed.

Video clips:
antenna-track-vid.wmv 475kb
antenna-track-vid.mov 3.4Mb

This project is still in the IDEA phase, but will be realized as soon as I get time !

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Thomas Scherrer OZ2CPU Sep 2007