what would be a 'default' position should that link be lost?
- Continue on current heading.
- Enter an orbit.
- Self destruct.
Nope. Here is how it should be handled:
- On "link lose" Return to Base
- If unable to RTB then find the closest safe place and Land
- If can't get to a safe place, wait until you have got fuel and then
self destruct
Beyond that, there must be an independent onboard module checking the sanity of drone's decisions/actions.
That module must include an override routine similar to this:
- If a "Land" instruction has been issued and we are in hostile territory then
- Contact and get confirmation from Base
- If can't contact base then Cancel the "Land" instruction.
- If can't cancel the Land instruction, then
self destruct.
- If can't "self destruct" either, then send a message to the control room: "we are screwed".
Why couldn't it RTB?
Even for some reason it can't have GPS localization at that time, it must have some secondary less accurate localization mechanism (like bearing-only SLAM) to fall back to. It just has to go back close to the base. It's much more likely to find a non-hostile territory there to land.
However, this drone somehow landed in hostile territory.
So it's designers have been super stupid and the drone lands as soon as it loses link?
So from now on, whenever Iran detects an RQ-170 it has just to Jam it and it lands neatly without making a whim!
Is that what you are telling us?
If you can't believe that the designers were SO STUPID, then it must be that, Iranians had somehow overridden the default routines of the drone.