How does Radar and Navigation Systems Work?

everinsta.com – Radar, short for “Radio Detection and Ranging,” is a system that utilizes radio waves to detect, determine the distance, speed, and direction of objects in its surrounding environment.

Here’s how radar generally works:

1. Transmission of Radio Waves: Radar generates electromagnetic radio waves that are transmitted into space or toward objects in its vicinity. These waves can be in the form of microwaves or radio waves.

2. Reception of Returning Waves: When radio waves reach an object, some of them are reflected back to the radar. This phenomenon is known as “backscatter.” The amount of reflected waves depends on the physical properties of the object, such as its size, shape, and material.

3. Reception and Signal Processing: Radar has a receiver to capture the reflected waves. The receiver converts the received radio signals into data that can be further processed.

4. Signal Analysis: The received signals are analyzed to determine the distance, speed, and direction of the object. This is done by considering the time it takes for radio waves to travel to the object and back (providing information about the distance), as well as the frequency changes of the waves caused by the Doppler effect (providing information about the object’s speed).

5. Data Presentation: The analysis results are presented in visual or numerical form to the radar operator. This could be a screen display showing information about the object’s position, speed, and other attributes.

6. Further Action: Based on the information provided by radar, the operator or automated system can take appropriate actions, such as avoiding collisions if objects are approaching, tracking specific objects, or alerting authorities.

Radar is used in various applications, including aviation and maritime navigation, weather monitoring, air and ground traffic control, as well as military applications such as air surveillance and air defense.

Here’s a summary of how radar works:

1. A magnetron generates high-frequency radio waves.

2. A duplexer switches the magnetron to the antenna.

3. The antenna acts as a transmitter, sending narrow beams of radio waves through the air.

4. Radio waves hit enemy aircraft and bounce back.

5. The antenna captures the reflected waves during the break between transmissions. It’s worth noting that the same antenna serves as both a transmitter and receiver, alternately sending out radio waves and receiving them.

6. The duplexer switches the antenna to the receiver unit.

7. A computer in the receiver unit processes the reflected waves and displays them on a TV screen.

8. Enemy aircraft appear on the radar TV screen along with other nearby targets.

Whether mounted on aircraft, ships, or anything else, a radar set requires the same basic components: something to generate radio waves, something to send them into space, something to receive them, and some way to display the information so that radar operators can quickly understand it.

The radio waves used by radar are generated by a device called a magnetron. Radio waves are similar to light waves: they move at the same speed—but their waves are much longer and have much lower frequencies. Light waves have a wavelength of about 500 nanometers (500 billionths of a meter, which is about 100–200 times thinner than a human hair), while the radio waves used by radar typically range from a few centimeters to one meter—finger-length to arm’s length—or about a million times longer than light waves.

Both light waves and radio waves are part of the electromagnetic spectrum, meaning they consist of patterns of fluctuating electric and magnetic energy traveling through the air. The radio waves produced by a magnetron are actually microwaves, similar to those produced by a microwave oven. The difference is that the magnetron in radar has to send those waves much farther, not just a few inches, so they’re bigger and more powerful.

Once the radio waves are generated, an antenna, acting as a transmitter, throws them into the air in front of it. Typically this antenna is curved so that it focuses the waves into a tight beam, but radar antennas also typically rotate so they can detect motion over a wide area. Radio waves spread out from the antenna at the speed of light (186,000 miles or 300,000 kilometers per second) and keep going until they hit something. Then some of them bounce back toward the antenna in a reflected radio wave beam that’s also traveling at the speed of light.

The speed of those waves is crucial. If an enemy jet plane is approaching at speeds of more than 2,000 mph (3,000 km/h), the radar beam has to move much faster than this to reach the plane, bounce back to the transmitter, and trigger the alarm in time. That’s not a problem, because radio waves (and light) move fast enough to circle the world seven times in one second! If the enemy plane is 100 miles (160 km) away, a radar beam can travel that distance and back in less than a thousandth of a second.

The antenna also acts as a radar receiver as well as a transmitter. In fact, the antenna alternates between the two jobs. It typically sends radio waves for a few parts of a second, then listens for reflections for a period of a few seconds before sending again. Every reflected radio wave that’s caught by the antenna is directed to an electronic device that processes and displays it in meaningful form on a TV-like screen, which is constantly watched by a human operator.

The receiving equipment filters out useless reflections from the ground, buildings, and so on, only displaying significant reflections on the screen itself. By using radar, an operator can see nearby ships or aircraft, where they are, how fast they’re moving, and where they’re headed.

Watching a radar screen is a bit like playing a video game—except that the dots on the screen represent real planes and ships and small mistakes could result in a lot of lives lost.

There’s one more crucial device in a radar set. It’s called a duplexer and it makes the antenna switch back and forth between being a transmitter and a receiver. When the antenna is transmitting, it can’t receive—and vice versa. See the diagram below to see how all parts of this radar system are interconnected.