What is CW Radar : Advantages and Disadvantages

CW (Continuous Wave) radar continuously transmits a radio frequency signal to detect moving targets and measure their velocity using the Doppler effect. It is commonly used in speed detection and industrial sensing applications. Advantages include simple design and accurate velocity measurement, while disadvantages include inability to directly measure target range.

Introduction:

The radar which works based on the use of continuous waveforms to determine target velocity is known as CW radar.

It works as follows: The frequency of the radar return wave (i.e., echo) remains at the center frequency (f0) from a stationary target, while it shifts by an amount equal to the Doppler frequency from a moving target.

By measuring the frequency difference, the target’s relative velocity can be measured using CW radar.

The figure below depicts a block diagram of the CW radar with transmitter and receiver parts.

The velocity of a moving target is measured using the following equation:

Target velocity, Vt = (fd/ft)* (Vo/2)

Where:

• fd = Doppler shift frequency
• ft = Transmitter frequency
• Vo = Free space velocity of EM wave

CW radar can be used for the following:

• To indicate the presence of a moving target.
• To find the radial velocity of a moving target.
• To find if an object is moving towards or away from the radar.
• To find a target’s bearing angle and elevation angle.

Advantages of CW Radar

1. It is used for relative velocity measurement.
2. It is used for a wide variety of applications as listed above.
3. It transmits power with a lower value and hence does not interfere with other wireless devices.
4. It is simple in construction.
5. The performance of CW radar is not affected by stationary targets.

Disadvantages of CW Radar

1. It does not measure the range or distance of the target.
2. It becomes difficult to make a decision when there are a large number of targets. In this situation, the CW radar system gets confused.

Summary

Continuous Wave (CW) Radar is a valuable radar technology primarily used for measuring the speed of moving objects by utilizing the Doppler effect. Advantages include simplicity and Doppler accuracy, while disadvantages include limited range measurement capability.