Originally Posted by
Skyjob
A simple autonomous device, located in tail, transmitting position from a integrated GPS through Inmarsat each minute... Seems simple enough.
Fitted with internal batteries which could be charged only on ground from AC system, no link to flight deck required.
It would seem simple enought to get around by using a £100 'truck driver' GPS jammer placed near the device. This would prevent the device from knowing where it is. And as such, a Geostationary satellite wouldn't be able to locate the device. The LEO satellites that do a Doppler fix seem to rely on the target being motionless so it is just the satellite to surface motion that is considered. In addition, there are significant coverage gaps (up to 2 hours).
Some basic improvements would help for tracking aircraft oceanic aircraft. However, my understanding is that the wrecks of both AF447 and QZ8501 were located within a couple of miles of the last electronic datapoint. So for accidents, we are talking about a technology that might shrink the search area a small amount and might speed up the investigation, but not fundamentally change anything.
For someone who wants to disappear and can fly the aircraft, I think all of the ideas proposed so far are either unsafe (high power complex equipment with no off switch) or relatively easy to defeat.