Sonar is used to look into underwater parts that are inaccessible by divers and other equipment. Sonar can be applied for a variety of purposes and tasks and is usually classified as active or passive. Let’s go over the ways sonar is used in everyday life as with military and scientific applications.
The Two Types of Sonar
Passive Sonar
Consists of only receiving equipment, with no transmission capability. Passive sonar systems are mainly used to detect noise generated by propellers or machinery on manned submersibles or submarines. The echo sounder is an example of a passive system that was once widely used for determining water depth.
Active Sonar
Uses the transmission equipment as well as the receiving equipment. Active sonar emits pulses of sounds and then “listens” for the returning echoes. Active sonar is used to detect and monitor submerged objects and measure water depth and bottom contour, locate underwater obstacles, track marine mammals, assist with navigation, and search for other vessels.
Applications of Sonar Technology
Water Depth Measurements
SAR, or Synthetic Aperture Radar, uses a single antenna to transmit pulses of sound or ultrasound that then reflect off objects and return an echo. The time it takes for the pulse to return is calculated, which gives information on the depth of the water. Water depth measurements are especially important when navigating ships or submarines.
Fishing
Fishermen can use sonar to find schools of fish, as well as to measure water depth and temperature. These readings help the fisherman understand where the best place might be to drop their nets or traps.
Some fishermen also use sonar to locate schools of fish so they know where to take their boats for a better chance at catching more fish.
Detecting Marine Mammals
Sonic sensors can detect marine mammals by transmitting pulses of sound and recording their echolocation via a receiver connected to an underwater hydrophone.
This activity is important because it could prevent future man-made noise from affecting the animals, as well as keep them away from dangerous areas like fishing nets.
Weather Forecasting
Using echoes from pulses of sound or ultrasound, scientists can measure temperature gradients in the atmosphere. This information helps them predict atmospheric conditions and the formation of weather patterns.
Oil and Gas Exploration
In addition to mapping the ocean floor, sonar is used for oil and gas exploration. It is especially useful when looking for petroleum deposits underwater because it shows a clear picture of the ocean floor.
Sonar is used to find oil and gas under the surface of our oceans, by giving information on what lies beneath the sea bed.
Military Uses for Sonar
The Marine Sonar Surveillance (MSS) program
A U.S. Navy system designed to protect surface ships from potentially hostile submarines. The system uses an array of underwater hydrophones for detecting and tracking submarines in coastal waters.
The U.S. Navy has a budget of almost $1 billion to improve the MSS program, which can now track nearly 200 vessels simultaneously.
The system’s hardware was upgraded in 2020 to quadruple its detection capabilities to better protect against attacks that may come from more technologically advanced countries like Russia.
Long-Range Identification and Tracking (LRIT) system
The LRIT system tracks large commercial vessels, including unique identifications, positions, course, speed, and status. It was developed as an international agreement between many countries under IMO (International Maritime Organization), to provide real-time information to coastal stations so they can monitor nearby ships.
This is an improvement of the original International Maritime Satellite (Inmarsat) system, which was used to broadcast vessel positions at sea and had limited accuracy.
SURTASS (Surveillance Towed Array Sensor System)
SURTASS Emits pulses of sound and listens for echoes to detect submerged objects and measure water depth and bottom contour, locate underwater mines, track marine mammals using directional hydrophones, and identify submarine-launched torpedoes by their unique sound signatures.
SURTASS emits pulses of 200 to 260 kiloHertz that are able to travel over 100 miles away from the SURTASS ship before they start to lose power.
NAVSEA In-Service Mine Detection System
The NAVSEA In-Service Mine Detection System, or NIMDS, is a U.S. Navy program to upgrade existing minehunting technology to detect mines more effectively and with greater reliability than previous sonar systems.
The system includes a digital receiver and an automatic identification system (AIS) that will send the system’s position to other ships in the area. Improvements include new software, undersea processing capabilities, and more efficient computing algorithms.
Scientific Uses of Sonar
Detecting Underwater Currents
Yes, sonar can detect underwater currents. A current is a body of water moving in a particular direction. Ocean currents are frequently associated with wind patterns and the movement of surface waters by the gravitational pull of the Moon and Sun.
Surface currents flow undersea by winds or other forces to form powerful, swift flows known as submarine currents. Sonar can detect currents depending on the strength of the signal being reflected back.
Underwater Archeology
Sonar has been helpful for underwater archeology by mapping and measuring the depths of submerged areas. Using sonar can help records and maps more accurate representations of some archeological sites, while also uncovering new sites that might have otherwise remained hidden.
Many archeologists studying shipwrecks consider this method to be one of the most important modern advancements, because of the ability to detect objects that are not accessible by divers.
Detecting Thermoclines
Sonar has helped scientists detect underwater thermal gradients or thermoclines. Thermoclines are layers of water with different properties, which can vary by depth.
These layers are often made visible in the shallower parts of the ocean when sunlight penetrates through it and is then separated into its component colors to create a rainbow effect. Different layers of water can act like different fluids, with each one moving at different speeds.
This means that sound waves will travel through the ocean at different rates depending on which layer they are in. Scientists use sonar to detect these thermoclines and record information about them.
Tracking Fish
There are ocean transponders that have been used to track fish and other sea creatures. These transponders can emit a signal up to 200 km away from the tagged animal, which helps scientists identify where it is located.
Scientists use this information to monitor migratory patterns of certain species as well as the number of fish in a certain area. They can also use the information to figure out how best to protect these species from overfishing.
Monitor Fish Populations
Fish farms use sonar to monitor fish populations in cages or nets under the surface of the water. Aquaculture mostly focuses on salmon farming, but other fish are also farmed. The sonar system is often used to monitor the health of the animals and for anti-predator protection.
One example of a system is the FARMSONAR, which is used for detecting foreign objects, predators, and fish. It also alerts workers onshore if there are any changes in conditions.
Survey Underwater Environments
Oceanographic sonar is a type of sonar designed to survey underwater environments such as oceans and seas. It is used by scientists to map the ocean floor, which helps them understand underwater geology.
Oceanographic sonar can also be used for other purposes such as finding schools of fish or dangerous objects under the surface.
Extracting Sediment Cores
Sediment coring sonar is a type of instrument that allows scientists to extract sediment cores from the ocean floor. These cores contain sediments, microorganisms, chemicals and other components that can help scientists study how the ocean has changed over time.
Scientists study various factors such as climate change and industrial pollution in order to learn more about past conditions on Earth.
Sediment coring sonar is also called a multi-beam sonar because it uses multiple beams to create a series of sound pulses.
This type of acoustic data is then recorded and analyzed in order to produce maps that can be used for different purposes.
Water Composition
An echosounder is a device that uses the principles behind sonar to measure depth and determine the composition of various features below the water’s surface. These measurements can help scientists understand where currents are located and how they affect aquatic life.
Echosounders can also be used to monitor sea ice thickness in order to predict future changes in climate patterns.
Final Words
Sonar is a very modern technology that can be used in maritime applications such as fishing and shipping. It has also been widely adopted for scientific purposes along with the military since its discovery. There are many different types of sonar systems that vary by the location and purpose of their application.
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