I thought aircraft was supposed to be stealth and not show up on radar under the right conditions. This article says

Removable Luneburg lens type radar reflectors are sometimes attached to military aircraft in order to make stealth aircraft visible during training operations, or to conceal their true radar signature.

So even with Luneberg lenses, will there be 2 blips on the radar screen, one from the reflector, and a weaker blip from the aircraft signature?

If I am potential adversary observing training involving stealth aircraft, is it possible to filter data around the "visible aircraft" to get its true signature? How is this difficult?

  • $\begingroup$ I’m pretty sure “conceal” here means to make the aircraft’s radar signature much worse during non-combat operations, so enemies won’t know how much smaller it will be during real combat. $\endgroup$
    – StephenS
    Jun 12, 2021 at 16:23

1 Answer 1


Since the attached reflector and the rest of the aircraft are at the same position and velocity, they form a single target. There will be no second blip. They're one and the same.

When a target has moving parts, like exposed engine blades, they distort the signal, producing a radar signature. This signature will be obscured by the much stronger reflection from the Luneberg lens.

This is a small side effect of the attached reflector's purpose: to allow allies to relatively easily track and target the aircraft. However, such a handicap also keeps them from experiencing stealth as it is and developing tactics to deal with it.

Even when high-res radar imaging is used, spatial separation alone is generally not precise enough to separate the signatures of other airframe parts from the removable reflector on its own. Engine signatures (JEM) can be separated through doppler shift. When the engines are concealed, there's not much in the way of distinguishing the airframe's static signature from the reflector's.

For more technical information, look into the subject of NCTR (non-cooperative target recognition).
Some ACARS papers can be easy to digest.
Pages 177-184 (28-1) make for a good starting points on the basics, 97-110 (8-3) address reflectors and their effect on the radar signature more specifically.

  • $\begingroup$ My impression is that Lunberg lenses or reflectors are used only during training to easily allow all participants to track the aircraft easily. It's not supposed to be used during actual combat? $\endgroup$
    – Nederealm
    Jun 12, 2021 at 17:27
  • $\begingroup$ It's definitely not meant to be used during combat. $\endgroup$
    – Therac
    Jun 12, 2021 at 19:35

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.