Question

Select TWO analytical tool that uses electromagnetic waves to measure velocity. Explain how each tool uses electromagnetic waves to measure velocity. Describe the region of the electromagnetic spectrum that the tools you selected use. What properties distinguish each of these two regions of the spectrum from other regions?

Answer 1

Tools you could consider are LIDAR and RADAR.

LIDAR

Stands for Light Detection and Ranging.

The working principle of Light Detection and Ranging system is really quite simple. A LIDAR sensor mounted on an aircraft or helicopter. It generates Laser pulse train, which sent to the surface/target to measure the time and it takes to return to its source. The actual calculation for measuring how far a returning light photon has traveled to and from an object is calculated by

Distance = (Speed of Light x Time of Flight) / 2

LIDAR’s generally use light in the near-infrared, visible (but not really visible), and UV spectrum’s.

RADAR

The RADAR (Radio Detection and Ranging) system works in much the same way as the LiDAR, with the only difference being that it uses radio waves instead of laser. In the RADAR instrument, the antenna doubles up as a radar receiver as well as a transmitter. However, radio waves have less absorption compared to the light waves when contacting objects. Thus, they can work over a relatively long distance.

RADAR uses radio waves to compute velocity.

They are both electromagnetic waves. The only difference is frequency. Radio waves move through the air the same way light waves do. They just go through it almost as if it weren’t there. Like light, in a vacuum, they move in something like straight lines when viewed on a large scale.