I thought that was only really an issue if the fiber was damaged in any way. (It would create a point where the external light could refract into the core) Then again, there isn’t going to be a sheath on that cable and its not exactly a sterile environment.
As long as the angle of attack is between 90°-45° between 0->50->0 % of the external light will enter. No matter your angle of attack, half of the light at least is always going to be reflected. The angle of total internal reflection is 45°, so as long as you are greater than that there wont be “total external reflection” aka no light can enter. The issue is that(barring the refraction of the light as it passes through the air/fiber medium) the angle of attack once in the fiber is still maintained, meaning it does not achieve total internal reflection and therefore passes through the cable without interfering at all(in the case of a atraight cable.
In practice, no cable is going to be perfectly straight, and i would imagine the air/fiber medium may bend certain angles enough to where they can enter above the needed angle of attack, but once inside are bent to be under the needed angle of attack. Both of those imperfections would allow this type of attack to work. In reality all you would need to fix this is to use rolling polarities with very minor error correction. On board the drone give it a 10$ thermal infared lens and a basic processor. Tell it if the cable either cannot be read or is missing while the drone is in flight, it targets the last heat signature it saw.
I thought that was only really an issue if the fiber was damaged in any way. (It would create a point where the external light could refract into the core) Then again, there isn’t going to be a sheath on that cable and its not exactly a sterile environment.
Meh, I’m an idiot and that’s OK!
As long as the angle of attack is between 90°-45° between 0->50->0 % of the external light will enter. No matter your angle of attack, half of the light at least is always going to be reflected. The angle of total internal reflection is 45°, so as long as you are greater than that there wont be “total external reflection” aka no light can enter. The issue is that(barring the refraction of the light as it passes through the air/fiber medium) the angle of attack once in the fiber is still maintained, meaning it does not achieve total internal reflection and therefore passes through the cable without interfering at all(in the case of a atraight cable.
In practice, no cable is going to be perfectly straight, and i would imagine the air/fiber medium may bend certain angles enough to where they can enter above the needed angle of attack, but once inside are bent to be under the needed angle of attack. Both of those imperfections would allow this type of attack to work. In reality all you would need to fix this is to use rolling polarities with very minor error correction. On board the drone give it a 10$ thermal infared lens and a basic processor. Tell it if the cable either cannot be read or is missing while the drone is in flight, it targets the last heat signature it saw.