I’ve recently come across a new patent publication from Stratech, here’s the link.

I’ve not been through the whole patent in detail (the bits I read made me so angry I had to stop myself from reading the rest), but the small amount I’ve read, I would consider to be a little misleading, here are some examples

“While radar is an excellent means to detect metal objects, it is less sensitive in detecting non-metallic objects, such as rubber. Objects made of materials having poor radar signature (e.g. rubber) can cause major problems for such radar-based systems. Further, radar may not be relied upon for detecting smaller non-metallic objects.”

Yes, radar is less-sensitive to non-metallic objects, but I’ve been on a runway and seen a radar system detect a very small clump of grass.

“Further limitations include radar blind spots or shadows due to blockages caused by other objects or infrastructure.”

It’s true, radars cannot see through solid objects (another way to say that is that radars “detect solid objects”!),  visible (or thermal) cameras can also not see behind “objects or infrastructure”. I’m intrigued to see what technology they are using that enables them to see through solid objects!

“In addition, radar may trigger a false alarm by indicating a strong signal for signals reflected from even small metal objects that may not be so hazardous”

Say what now? is this actually trying to say that the ability to detect small metal objects is a bad thing? I’d like to know exactly which metal objects that are about to be sucked into my jet engine I should not be concerned with!

Anyway, that’s enough about radar, let’s move into the infra-red (the shorter wavelengths are far more interesting anyway).

“Some airports utilize infrared or thermal-imaging systems to detect objects, cracks voids etc. on a runway. However, systems employing infrared or thermal-imaging systems can only sense the infrared radiation (emitted from objects)….”

Really?, so there’s no infra-red energy reflected from objects by that tiny IR emitter in the sky we call the Sun? it’s all emitted?

“…..which is outside the thermal equilibrium of the surroundings i.e. a infrared or a thermal imaging system can only detect objects (e.g. a piece of warm metal debris on a cool runway) which have sufficient thermal contrast. Small objects which have poor thermal contrast may pose significant challenges for infrared / thermal imaging system”

again, reflected IR radiation from the Sun excludes some of these issues, but the emissivity of the objects is also a major factor, two objects of the same temperature can have a high IR contrast due to their different emissivities.

And let’s not forget, visible cameras also require contrast, it’s hard to see a loose piece of concrete on a runway which is made of concrete, they tend to be the same colour (and the same temperature, and have the same emissivity!)…….it would be no problem for a radar though