Giatto said:
Do you know any long range wireless communication gadget (radio modem etc.)
that can be used for 115200 bits/sec continuous data transfer over 100 km ?
(Imagine you are on a boat/ship and you have a UAV. You want to fly your
UAV to 100km away and you want continuous comm with the UAV. Because one end
of the communication is an small airplane the smaller size and lighter
weight for the gadget are peferred.)
If your budget is not so limited,or just to learn some more about what
you are trying to do, go to http:\\ipmobilenetinc.com and then look into
their VHF systems. They can't do your 115200, but you should see what
all they can do with 19.2.
The biggest reason you can't get the speed out of the lower bands is
that the FCC and other governing bodies will not let you use the
bandwidth necessary.
To get any real speed out of a radio signal you have to move up into the
microwave range and then use some very nasty tracking algorithms to keep
your antennas aligned. In other words not happening.
IPMobileNET's diversity system is something you should look into
implementing, since it allows them to run the radios at lower power and
reception levels and to take advantage of signal bounce more
effectively. That mostly helps inside large cityscapes.
For open ocean and at the distances you are referring to, you are
probably going to have to drop back into the HF frequencies, or at least
VHF, but at high wattages and some expensive antennas. I hope you have a
large ship and UAV to work with.
The military uses satellites for its missile systems and or runs them
antonymous.
You are asking for a lot out of an all digital system is what I'm trying
to say.
I have to agree with the person who mentioned passing analog data
instead of digital. Lower your baud rate and send smaller packets. Send
your video back as an analog using a separate camera system from your
vision system as it will give more detail than your vision cameras will
anyway. Any other data I can think of you collecting will not take up
any where near the packet space except the sonar data and only if you
are trying to put together the composite picture on board the UAV
itself. That could turn into a real processor hog and would be done
better by ship board sonar mapping.
Just how much data are you trying to collect any way. Give us an idea
and we could probably help you better. The company I work for built the
Navy an ROV aircraft way back in the late 70's early 80's. I would like
to see more about this idea. I think it could be useful if it hasn't
already been done.
Eljin
)
