How to make dragons move stealthy on radar?

Question

What dragon exactly? Well, the ones in my story tend to be "smaller", around the size of a larger horse with wingspans of 10-12 meters. They have six limbs and are capable of powered flight. They use Javelins and hard-kill MPADS countermeasures instead of fire.

Of course, dragons can't and won't engage with high-end mechanized troops (tanks, fighter jets) and are instead deployed with light infantry, providing reconnaissance, transportation, and a little air support when necessary, until the real one arrives. You probably want to hold onto that anyway. It's bad practice to fire your strongest cards first.

However, having a volant teammate with rather large wings is going to be a problem when it comes to radars. Of course, that's only the case when they're flying but still, stealth is important, regardless of who you engage.

Visual contact usually happens when the dragon is out of range, so that's not so much a problem, plus they can move fast enough that following them without an aircraft is pointless and potentially dangerous.

Since storywise, dragons were genetically engineered to be a useful addition to the ranks of Black Troubleshooters (more on them in another question), it only makes sense for them to naturally be able to screw with radars, but how?

Answer 1

You should familiarize yourself with the expression radar cross-section:

Radar cross-section (RCS) is a measure of how detectable an object is by radar. Therefore, it is called electromagnetic signature of the object. A larger RCS indicates that an object is more easily detected.

An object reflects a limited amount of radar energy back to the source. The factors that influence this include:

• the material of which the target is made;
• the size of the target relative to the wavelength of the illuminating radar signal;
• the absolute size of the target;
• the incident angle (angle at which the radar beam hits a particular portion of the target, which depends upon the shape of the target and its orientation to the radar source);
• the reflected angle (angle at which the reflected beam leaves the part of the target hit; it depends upon incident angle);
• the polarization of the transmitted and the received radiation with respect to the orientation of the target.

While important in detecting targets, strength of emitter and distance are not factors that affect the calculation of an RCS because RCS is a property of the target's reflectivity.

Radar cross-section is used to detect airplanes in a wide variation of ranges. For example, a stealth aircraft (which is designed to have low detectability) will have design features that give it a low RCS (such as absorbent paint, flat surfaces, surfaces specifically angled to reflect the signal somewhere other than towards the source), as opposed to a passenger airliner that will have a high RCS (bare metal, rounded surfaces effectively guaranteed to reflect some signal back to the source, many protrusions like the engines, antennas, etc.).

You indicated in your previous questions that your dragons seem to be horse-sized or something. When a target the size of a seagull shows up on radar, operators know that it is either a seagull-sized bird or a stealth plane. If your dragon has stealth features, maybe due to wearing special-taylored vests that cover even the wings, then it might not even appear in radar. If the dragon does show up as a horse-sized bird, then the enemy will know that something unusual is coming.

Also notice that when expecting aircraft, radars point at an angle upwards; it makes no sense to scan the horizon in radar in many kinds of terrain, due to hills, mountains or forests either providing cover to the enemy or scattering signals. Flying low in such cases helps avoid detection.

Answer 2

Given you're using a made-up creature, you could easily work around radar by modifying its structure and behaviour.

• Flying under the radar: not just an expression, it means flying too low for the radar to accurately pick up a signal due to interference from the ground. An animal could easily do that, making radar pretty useless (with the downside of being easy to spot from the ground).
• Anatomy: let's start with shapes. Most stealth planes use specific shapes to make sure the radar electromagnetic waves won't bounce back, greatly reducing their echo. Your dragon could be built in such a way to implement this.
• Materials (1): radar works best on objects that conduct electricity. If your dragon skin/scales are non-conductive, the echo will be much weaker.
• Materials (2): there's such a thing as radar-absorbent materials. Both their composition and shape contribute to reduce the echo. Your dragon scales/skin could be made in such a way.

To give you an idea, the notorious B-2 Stealth Bomber only produces a very small echo (similar to an insect) thanks to its shape and materials, even though it's a 21 meters long plane with a 52.4 meters wingspan.

I'm sure by playing with the composition of your dragon scales and its body shape, you can easily get there too, especially since you're "only" as big as a large horse.

EDIT: I haven't mentioned specialised equipment, since you asked for a "natural way" to avoid radar. You might ask yourself "Why" would your dragon evolve to have anti-radar features though. Was it by chance (maybe they picked dragon specifically because of it)? Was it genetically altered for that purpose?

Answer 3

While the above answers give some good 10000-foot level descriptions of radar detection issues, the meat and bones of it are much more complex. To simplify even further though, geometry is one of the most important factors.

If your dragon can reconfigure its scales to alter the angle of reflection to be something pointing away from the detection element of the radar system, then it will effectively be entirely invisible to radar. This requires knowing where the source and detector are located and being able to individually control the alignment of all of it's scales (which have complete body coverage).

If you wanted to "screw with radars", you could always reflect a varying amount of energy back to the detectors. This could make you appear to be changing in size or even speed. But I'd imagine invisible would be the best option.

Answer 4

Your dragons have a key advantage not enjoyed by other air vehicles: they can run along the ground literally in the weeds, and take off again at will. If they fly along at treetop level and land/take cover as soon as their radar warning reciver (RWR) tells them some has locked on to them, no missile is ever going to be fast enough to hit them. The enemy might waste a lot of shots trying.

Their second advantage is being able to reconfigure mid-flight: they can change (and minimise) radar signature at will simply by folding up their wings. So the cool thing to do it attravct a radar -guided missile, then, as it approaches, simply ball up and disappear briefly from radar while it whizzes past, then resume flight, Missed me!

Thirdly, carry a lot of radar decoys and drop them when targeted.