All the best things tend to come in threes, like 

• the Laws of Robotics. 
• the number of Lord of the Rings books (if you don't count The Hobbit). 
• the Seven Samurai (well, what's left of them, anyway).

Radar's no exception to that rule, except it's more of a three main components kind of deal. A basic radar system has

1. a way to transmit radio waves.
2. a way to receive radio waves. 
3. a way to display the data.

We're abstracting a little too much, though, so let's get into the actual pieces. The transmitting system has an oscillator, an amplifier, a modulator and an antenna connected to a duplexer. (Don't remember what any of these are? Head back to the Electrical Engineering Hardware section.)

The receiving system has a demodulator, an amplifier, an analog to digital converter, and another antenna that is connected to the duplexer. Finally, the visual display takes the information from the transmitter and receiver and displays it so that we puny humans can understand what's going on in the sky.

Making Waves, Catching Images

With this radar system, we can detect moving and stationary objects and maybe…just maybe…create a radar image. It's all based on the reflections of radio waves. Radio waves reflect off of metals (and other materials) in the same way that light reflects off a mirror.

There's a whole learning guide on visual light if you're interested. If not, we're just going to keep going with this radar business.

Radar at its core might be all about bouncing waves and listening for the reflections, but the actual system needs to do much more. If they only recorded the reflected waves, our detection system wouldn't actually be able to tell the difference between different objects. A radar that only detects the reflected energy just gives you a bunch of points with different colors. The only problem is that we don't know where a color point original came from. Stationary objects are no big deal, but moving objects like airplanes or tanks?

Big deal. Very, very big deal.

Complicating the Image

Say you've got one of these systems and you're looking for green dots, which are tanks. You see a green dot pop up on the screen, but you also see a smattering of blue and yellow dots, representing deer and rabbits, respectively. Both are important to avoid, but you don't really need to, strictly speaking (bye, bye, Bambi's mom).

And yet…the blue and yellow dots are so close together that they almost…blend…to green. Is the green dot you're seeing actually a green dot, or is it a blue-yellow combination? There's no way to tell from the current system whether shooting at that green dot is going to win you the war or inspire a new talking animal movie with a tragic death.

Adding the phase (how far the wave has shifted from the original wave's location) to the wave information you collect will give you lines of colors, which give you a better sense of where something is, but you still aren't getting a complete view of the scene. With lines, you can triangulate a potential location of all of the green points found between the different radars, but you still have no way of knowing if you're looking at the enemy or Thumper. It's just too ambiguous.

The Cure for Radar: More Radar

One possible solution: getting more radars. If you add radars around a scene, you'll give more angles to send and receive information. As long as you can be sure of where every radar is and that they're all turning on and off at the same time.

Getting those different angles forms a two-dimensional image of the reflected rays. Don't get us wrong: you're still going to get ambiguities, seeing as you're trying to map a three-dimensional space onto two dimensions, but at least you'll be able to see clearly which dots are green and where they are on a map (within a small margin of error).

If you go a step further and add an elevation angle or a way to detect wavelengths, you can improve the resolution—reducing the ambiguities in the radar image even more.

Just in time, too. You were a little close to becoming the villain of the next animated Disney blockbuster.