What is the difference between active sonar and passive sonar? What are the main application scenari

Active sonar is throughActively send sound wave signalsto detect objects in the waterHydroacoustic equipment

Passive sonar, yesDo not sendsound signals, but throughListen to other objects emittingacoustic signals to detect objects in the waterHydroacoustic equipment

They are all underwater acoustic devices.

Because in the water, electromagnetic waves.

The signal decays quickly and travels over a small range (e.g. almost no photosynthesis is used below 200 meters in seawater).

algae), so acoustic equipment is mostly used to detect underwater targets.

Sound is a mechanical wave.

In a denser object, the greater the propagation velocity. Water is 1,000 times denser than air, and the speed of sound in water.

It's about 1450 meters in seconds, which is much higher than the speed of sound in the air of 340 meters and seconds.

Also due to the high density of water, the viscosity is also greater than that of air, so the resistance to move in water is greater than that in air, and the speed of movement in water is lower.

In this way, it is advantageous to use sound waves to detect moving objects in water. Sound waves are almost the only device suitable for detecting objects in water.

Active sonar, the equivalent of a bat's mouth and ears.

Passive sonar. Equivalent to a bat's ear.

Destroyer. Because the speed of destroyers and *** is faster than that of submarines (about 30 knots for destroyers, only about 6 knots for conventional submarines, and about 20 knots for nuclear submarines), and it is easier to damage control on the surface, and it is relatively easy for personnel to evacuate when attacked, so destroyers and *** will turn on active sonar.

Sonar buoys can be dropped.

Both destroyers and *** can drop depth charges, or anti-submarine torpedoes (generally 324 mm diameter).

Actively sending sound signals in the water will reveal your own position, so that it can be detected by the passive sonar of the other party. Therefore, when submarines are underwater and submerged, they generally only use passive sonar. Active sonar is turned on only briefly when a torpedo is fired to attack the target.

Because the density of water is greater than that of air, it is difficult to compress, so the energy of the torpedo** decays more slowly in the water, and the lethality of the submarine is great under the same power.

The submarine is underwater, and it is also under tremendous pressure from the seawater. Once the pressure-resistant shell is damaged, it can only float quickly and lose its combat effectiveness. Otherwise, the pressure of the sea water will quickly destroy the structure of the submarine, and then it will have to sink to the bottom of the sea.

This is also the fact that anti-submarine torpedoes have a smaller caliber, 324 mm in the majority. And anti-ship torpedoes have a larger caliber, generally for the reason of 533 mm (Russia has 650 mm heavy torpedoes).

They are all underwater acoustic devices. Active sonar is a hydroacoustic device that detects objects in water by actively sending sound wave signals.

Passive sonar is a hydroacoustic device that does not send sound wave signals, but detects objects in water by listening to the sound wave signals emitted by other objects.

To put it simply, active sonar is the mouth and ears, shouting sounds, hearing echoes, and determining the target distance.

Passive sonar only has ears, listens to various sounds, and can only estimate the position and bearing.

Active sonar is accurate, but easy to expose, and passive sonar is hidden, but not accurate.

Active sonar is suitable for detecting icebergs, reefs, shipwrecks, sea depths, fish, mines, and concealed submarines with engines turned off;

Passive sonar is especially suitable for submarines that cannot make a sound to expose themselves and want to detect the activity of enemy ships.

One is to detect objects by emitting sonar themselves, and the other is to detect by listening or discovering other objects emitting sonar.

Active sonar is generally used to detect some fixed objects or fish, and passive sonar is generally used in the military, which is used to detect the sonar of other ships or other armies.

They are mainly used in different places, active sonar is a hydroacoustic device that detects underwater objects by actively sending acoustic signals. Whereas, passive sonar is a hydroacoustic device that detects underwater objects by monitoring the acoustic signals emitted by other objects instead of emitting acoustic signals.

1. The principle of active sonar is actually exactly the same as the radar we are familiar with, but the carrier is different, one is the use of electromagnetic waves, and the other is the use of sound waves.

2. Different from passive sonar, active sonar does not passively listen to the sound in the water, but emits a certain frequency of sound waves, which are centered on the emission point and emit a 360° range around them. When a sound wave hits an object, it is reflected back.

3. The speed at which sound waves are transmitted in water is basically constant. In this way, people can actively detect the distance, direction and speed of objects in the water. Or avoid obstacles while snorkeling.

The principle of reception is the same for active and passive sonar. The difference is that active sonar is that the detector actively emits sound waves, and then detects by echoes. Passive sonar, on the other hand, only receives sound waves.

The advantage of active sonar is that it has a long detection range and a strong ability to detect targets. But it's easy to spot.

The benefit of passive sonar is that it is silent and does not reveal its position due to use. However, the performance is much worse, especially if the noise of the measured target is close to or even less than the background noise of the ocean, it is basically blind.

Active sonar emits sound waves by itself, and then judges the shape and distance based on the sound waves returned, but the sound waves emitted by active sonar may be received by the other party, thus revealing their own position.

Passive sonar only receives the sound of water emitted by the target, etc., and is used to determine the position of the opponent.

Not the characteristic of active sonar, the sail is round.

a.Good concealment.

b.Easy to expose.

c.Reconnaissance distance zone is slowly approaching.

d.Effective against stationary silent targets.

Correct answer: a