On Mon, 31 Oct 2016 15:25:30 -0700, Jeff Liebermann
wrote:
The limiting factor with
RC is usually the antenna on the drone or whatever. Getting a decent
pattern is difficult so they resort to hemispherical or half
hemisphere antennas. This results in lousy gain, but works when doing
aerobatics and inverted. That puts the load on the ground antenna
system, which in my never humble opinion, can only be done effectively
with a high gain antenna (not too high) and tracking/pointing.
Sorry... I had to disappear abruptly. I forgot that I had a service
call scheduled. Blundering forward:
There are people who have done tracking correctly:
http://diydrones.com/profiles/blogs/the-expensive-but-attention-grabbing-antenna-tracker
http://diydrones.com/profiles/blogs/build-your-own-antenna-tracking-pan-tilt-system
Needs work:
https://vimeo.com/127533208
https://vimeo.com/129155928
Mo
https://www.google.com/search?q=drone+antenna+tracking&tbm=isch
I have my own scheme for tracking a drone. The drone continuously
broadcasts its lat/long/altitude to the tracker. The
lat/long/altitude of the tracking antenna is known, so the antenna
aiming azimuth and elevation can easily be calculated. The algorithm
is messy because the drone only sends its position every 500 msec. If
the drone moves outside the beamwidth of the tracking antenna during
this 500 msec, the signal will be lost. Fortunately, it can be
recovered with manual aiming. Therefore, it works best at the far end
of the radio range, rather badly close in, and especially badly when
flying overhead. Predicting the drone's current location based on
flight path (as in a gun laying radar system) works well. If you do
the reverse, and have the drone controller determine the flight path,
the position of the drone will always be known, so flying out of the
antenna beamwidth will not be a problem. Mission Planner software
does this nicely.
http://ardupilot.org/planner/docs/mission-planner-overview.html
Good luck.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558