Whether you’re interested in a career in radar technology or simply find it a fascinating innovation, you’ll need to learn the basics before you can understand how complex radar systems work. Here is our guide to the radar basics and terminology you’ll need to know.
What Does RADAR Stand For?
Many people new to the world of radar technology have a general idea of what radars are, but don’t know that “RADAR” is actually an acronym for “radio detection and ranging.” Radars use radio waves to detect objects and better understand their position, distance, speed, and range.
Types of Radar Systems
There are dozens of types of radar systems, but when discussing radar basics, we focus on two of the most common: continuous wave and pulsed wave.
Continuous Wave Radars
Continuous wave radar systems put out one constant signal. While this can make for higher-resolution feedback, it also makes the radars more detectable by opposing forces. This means they can be jammed and deterred more easily, making them less effective when stealth is necessary.
Pulsed Wave Radars
Pulsed wave radar systems repeatedly put out shorted signals. This saves energy, makes them less detectable, and prevents them from being jammed.
Principles of Radar
While they may seem elementary, having a grasp on these basic radar concepts is key in understanding simple and complex radar systems alike. They hold true for all sorts of applications, from weather and law enforcement to military radars. Check out this guide to radar basics and terminology.
Radar Signal Processing
Signals are electromagnetic radio waves produced by a radar transmitter. These signals travel through space until they eventually collide with an object and reflect or scatter.
RF (Radiofrequency) Energy
RF energy or RF waves are a form of electromagnetic energy that is used purposefully by humans or systems in controlled applications.
Illumination refers to the process of directing electromagnetic radio waves toward an object. While these waves can’t be seen by the naked eye, they “illuminate” potential threats and points of interest within a radar display.
Electromagnetic waves scatter or reflect when the medium they are traveling through changes. For example, waves are emitted and travel through the air. When they reach an object with a different density (like a tree or a building), they reflect to show that an object of some sort is present. The amount of information that the radar system can provide will depend on the complexity of the system.
Radar-absorbing materials are often used in the military on ships and aircraft to prevent this scatter and produce less of a reflection. While reflection is a complex process, it is one of the radar basics that even the simplest radar systems rely on.
Target reflectivity is how much of the transmitted power returns to the radar after reflecting or scattering off of an object. Depending on the type of radar system and the use case, the reflectivity can tell you more about the object’s material, size, speed, and more.
Modulation refers to the process through which waveforms can be varied or altered. Modulation typically occurs when data is converted into radio waves that can carry this data.
If you’ve ever heard an emergency siren, you’ve experienced the Dopper effect or Doppler shift. The Doppler effect (named for Austrian physicist Christian Doppler) is the change in frequency of a wave experienced when the observer is moving relative to the source of the wave. This is what causes the pitch of a siren to go up and down as the vehicle moves past you.
In radar technology, the Doppler effect is used to measure speed. A fixed-frequency wave is sent out, and the frequency of the reflected wave off an object can illustrate how quickly that object is moving toward or away from the wave source. No matter how complex radar systems get, most of them rely on the basics of the Dopper effect to provide information about their surroundings.