The latest ArduPilot Fail Safe firmware V1.6 includes a state of the art system to detected if we have glitches or bad signal, triggering the RTL and avoiding undesired "Remote Resets".
How it works?
Well, the first part is just a low pass filter that works only when switching to autopilot, this prevent undesired toggles to autopilot mode when the signals becomes "noisy" and also avoiding undesired resets (the system mistakenly thinks you are toggling the switch).
The second parts is a "Valid Pulse Width Checker", this is a very simple code that will increment a counter every good pulse received, if the system receive 75 valid frames (by default) it will thrust the commands we send through the remote control, otherwise will trigger RTL, and reinforces the prevention of undesired "Remote Resets" caused by noise.
Of course the latest code could be found in the same place as always, here
The Attiny has been tested only on ground with my 72mhz Futaba and two different receivers, after confirmation i will remove the beta tag, and i will try convince Nathan to flash it on the SparkFun boards, in the meantime you can try it with your AVR programmer. ;-)
Well right now I'm working on the new ArduPilot firmware code name "Hybrid", will support NMEA, SIRF , uBlox UBX and VENUS 10HZ GPS protocols, on the same code, and you can switch between them by just changing a single variable, bad news, only works on 328. =P