Active Radar vs. Passive Radar

Radar (Radio Detecting and Ranging) systems and systems that are designed to detect objects and to evaluate the distance between the objects and a single antenna or a group of antennas.

Both active and passive radars have advantages, and people prefer using either of them for different reasons. As they have advantages, they also have setbacks, which bring about their differences.

Active radar and passive radar have some differences, some of which are as follows.

1. In an active radar, the transmitter and the receiver are located at the same place, hence it is known as a monostatic radar whereas, in a passive radar system, the transmitter and receiver are located at a different place. This is why it is referred to as a bistatic radar.

2. Most people are more familiar with active radar as compared to passive radar. In the active radar, the principle of operation is very simple. A radio wave is released from the antenna and reflects off the objects that the wave encounters. Passive radar on the other hand relies on a signal transmitted from a different location.

3. In an active radar, the distance between the radar system and the object is determined using a simple time-of-flight calculation. In passive radar, the time delay is calculated with one transmitter and one receiver.

4. An active radar transmits microwave energy and receives the reflected echoes from the transmitted pulse whereas a passive radar is not really a radar, but a radio-frequency receiver that listens to the microwave transmissions.

5. An active radar actively sends out a radar pulse, in which it listens for the return signal. A passive radar, on the other hand, does not do anything but listens for the return pulse from other radars.

6. When using an active radar, it is like shinning a very powerful flashlight at something whereas, when using a passive radar, it is like using night vision that just amplifies what is already available.

7. An active radar is effective in gathering a lot more information, but it also gives away the location of the information gathering station. This means that if being traced, the information gathering station can easily be a target. A passive radar, on the other hand, gathers less information, and the information gathered is much harder to observe by other people as well. In this case, the passive radar is the best option to go for.

8. When talking about “passive radar jamming”, you are talking about things like chaff. These are things that absorb and reflect but do not transmit. On the other hand, when talking about “active radar jamming” it means things like BriteCloud that absorb, reflect, and also transmit.