Underwater ventures by human beings are not new. The first underwater vessel was invented back in the 17th century. Although they were fascinating, there always lacked a precise way of communicating with other underwater vessels. Enter SONAR technology.
SONAR, which stands for Sound Navigation And Ranging, isn’t quite a new technology, either. The first underwater experiment with sound technology was carried out by Daniel Colloden, back in 1822.
Subsequent research and studies led to the SONAR technology as we know it today. But is SONAR the ultimate answer to all underwater communication queries?
Like any other technology, SONAR has its advantages and disadvantages. But before we dive into them, let’s first briefly talk about how SONAR works and where it’s used in the current times.
How Does SONAR Work?
Put simply, SONAR is a system that detects sound waves emitted underwater. These sound waves could be coming from another ship, the floor of the sea, or marine animals.
How the system gathers the information depends on the type of SONAR being used. That brings us to the two types of SONAR, namely, passive SONAR and active SONAR.
Passive SONAR
The first SONAR devices that were invented back in the early 20th century were all passive SONAR systems. In such a system, sensors are engaged to continue to listen to any sound waves emerging down from the depths of the sea.
Anytime a target object such as a marine animal or another vessel passes by, and if it emits sound waves, the system reads them. These waves are then processed with various technologies that analyze them and find out the type of source that the sound was coming from.
Active SONAR
Active SONAR is a little more complicated but worth the extra setup. In an active SONAR system, a transmitter emits sound waves and a receptor waits for them to reflect from objects.
These reflected sound waves are then processed and analyzed. By calculating the time taken for a sound wave to come back, the system can estimate the distance at which the target object is located.
Applications of SONAR
Let’s now look at where the SONAR technology is used. Here are some of the most common uses.
Warfare
SONAR can be an effective way to detect the presence of enemy warships or submarines. The first SONAR devices were built around the first world war, although they didn’t get to be used in the war then. But since then, they have been effectively used to mark territories and deal with underwater battleships.
Fishing
This is one of the most common uses of SONAR. Modern-day commercial fishing boats are equipped with SONAR devices that can accurately read the presence of underwater life.
Combined with features that can detect the presence of birds, which effectively means fish is not far away, the SONAR technology has turned out to be a big boon for the fishing industry.
Seafloor Mapping
Using SONAR systems, navigators can easily find out the depth of the sea in various regions. All they have to do is send a few sounds waves, and wait for them to hit the bottom of the sea before coming back. And then, they analyze the waves to determine the distance of the seafloor from the surface.
General Navigation and Communication
SONAR systems come in handy when trying to navigate a ship safely through hazardous areas. SONAR can detect the presence of mines and other underwater threats. It’s also a great way to communicate with other ships or underwater vessels such as submarines as at greater depths, there remain no other means of communication.
Advantages of SONAR
Now that you know how and where SONAR systems are used, it’s time to look into some of the pros and cons of SONAR. Let’s start with the pros.
Cost-Effectiveness
In applications such as commercial fishing and seafloor mapping, the budget can be a huge factor. That’s why the ships used in these applications prefer using the SONAR technology. The setup is inexpensive and quite simple to operate.
Accuracy
Not many technologies work effectively underwater. Fortunately, SONAR is one of the few that hold up well. This is because attenuation is low in the case of SONAR compared to other forms of communication such as radar.
Versatility
With SONAR, you can hardly go wrong in detecting the presence of target objects. There are no other means of long-distance underwater communication that’s as effective as SONAR. It’s no wonder then that SONAR systems are used in a wide range of marine activities.
It’s not just the accuracy. SONAR excels in the speed of communication, too. A SONAR system can cover about 80% of the sea. And this property makes it extremely useful in detecting warships and seafloor imaging.
Disadvantages of SONAR
Despite being one of the surest and easiest ways to communicate underwater, SONAR does have some disadvantages. Let’s see what they are.
Marine Life Threat
SONAR can detect the presence of underwater life truly well. But it comes at a cost. Typically, a single sound beam cannot properly predict the shape and size of the object that it’s reflected from.
Hence, to understand the target object better, SONAR systems must use multiple, high-frequency sound waves. Such high-frequency waves do provide the desired accuracy. But they end up threatening the lives of marine wildlife, and sometimes also those of humans.
Noise
As multiple transmissions and reflections are required to get the estimations of target objects right, there’s also a high chance of creating a large number of misplaced and unusable sound waves, aka, noise, through the entire process. Moreover, the sea itself is a lossy medium and a lot of sound waves are scattered among the seawater before they hit the target or come back to the system.
Reverberations
Reverberation is the phenomenon in which sound persists even when some time has passed after the sound waves are produced. When a SONAR system sends out a sound wave, reverberations of those waves are inevitable. If reverberations happen more frequently, they could cause interference with the original beam. As a result, the accuracy of the system could suffer.
Takeaway
SONAR has been one of the most useful inventions of the past century, And thanks to its simplicity and cost-effectiveness, it’s still used in a wide range of applications.
SONAR is known for its accuracy and the potential to cover a wide portion of the sea. From detecting warships through fishing to seafloor mapping, SONAR has consistently provided satisfactory results.
However, they do have some drawbacks, the most relevant of which is the need to produce high-frequency waves that pose a threat to marine wildlife.
Yet, SONAR is widely accepted as the best mode of communication underwater and continues to be combined with a variety of modern technologies to further improve its functionality.