[Paparazzi-devel] Encryption of PPM frame

[Achim Walther]

Hello everyone,

while I was working on a new version of my PPM decoder for the 35 MHz
system the idea of encrypting the PPM signal crossed my mind. The basic
principle is once you have control over the signal in the RC transmitter
you can manipulate it in any way you want. Of course within the
bandwidth limitations. No more need for a 6 ms sync pulse etc. This way
one could protect a UAV from being hi-jacked when flying farther away.
It might not be sufficient to protect from jamming however.

Even though 2.4 GHz systems are not concerned with the problem of double
channel allocation there are still some 35 MHz users around.

I described the principle at the end of this page:
http://www.voidpointer.de/ppmswitch/index_en.html . One challenge is the
voltage of the signal in the transmitter having 9 Volts or higher. This
could be met using a special uC like the ATmega16HVB.

What do you think? Is R/C still a subject and would this be a valuable
feature? Or is dealing with PPM outdated now we have Zigbee etc.?

Regards, Achim.