Towed array

Towed array is a type of sonar system used by United States Navy, Royal Navy, and other navies, including the French Navy and Japanese Maritime Self-Defense Force, to detect and track submarines and other underwater vehicles, such as those used by the Soviet Navy during the Cold War. The system consists of a long array of hydrophones towed behind a ship, such as the USS Enterprise (CVN-65) or the HMS Queen Elizabeth (R08), which are connected to a processing system on board the ship, similar to those used on the Los Angeles-class submarine. The towed array is used in conjunction with other sonar systems, such as the AN/BSY-1 and AN/BSY-2, to provide a comprehensive picture of the underwater environment, including the detection of torpedoes and mines used by the Imperial Japanese Navy during World War II.

Introduction

The towed array is a critical component of modern anti-submarine warfare (ASW) systems, used by navies such as the United States Navy, Royal Navy, and French Navy, to detect and track submarines and other underwater vehicles, such as those used by the Soviet Navy during the Cold War. The system is used in conjunction with other sonar systems, such as the AN/BSY-1 and AN/BSY-2, to provide a comprehensive picture of the underwater environment, including the detection of torpedoes and mines used by the Imperial Japanese Navy during World War II. The towed array is also used by research vessels, such as the RV Knorr and RV Atlantis, to study oceanography and marine biology, including the work of Woods Hole Oceanographic Institution and the National Oceanic and Atmospheric Administration (NOAA). Additionally, the towed array has been used in search and rescue operations, such as the MV Doña Paz and RMS Titanic disasters, with the assistance of United States Coast Guard and Royal Canadian Mounted Police.

Principles of operation

The towed array operates on the principle of passive sonar, using hydrophones to detect the sounds made by submarines and other underwater vehicles, such as the Akula-class submarine and Los Angeles-class submarine. The array is towed behind a ship, such as the USS Nimitz (CVN-68) or the HMS Invincible (R05), at a depth of around 100-200 meters, and is connected to a processing system on board the ship, similar to those used on the Ohio-class submarine. The processing system uses signal processing techniques, such as beamforming and frequency analysis, to analyze the sounds detected by the hydrophones and determine the location and velocity of the target, with the help of NASA and Massachusetts Institute of Technology (MIT) researchers. The towed array can also be used in conjunction with active sonar systems, such as the SQS-53 and SQS-56, to provide a more comprehensive picture of the underwater environment, including the detection of seabed and water column features, as studied by the University of California, San Diego and the Woods Hole Oceanographic Institution.

Types of towed arrays

There are several types of towed arrays, including the thin-line array and the thick-line array, which are used by navies such as the United States Navy, Royal Navy, and French Navy. The thin-line array is a lightweight, compact array that is easy to deploy and recover, making it ideal for use on small ships and unmanned underwater vehicles (UUVs), such as the Bluefin-21 and Remora 3. The thick-line array, on the other hand, is a heavier, more robust array that provides better performance in noisy environments, making it ideal for use on large ships and submarines, such as the USS Virginia (SSN-774) and HMS Astute (S119). Additionally, there are also towed array sonar systems that use fiber-optic sensors and piezoelectric sensors, which are used by research institutions, such as the University of Oxford and the California Institute of Technology (Caltech), to study oceanography and marine biology.

Applications

The towed array has a wide range of applications, including anti-submarine warfare (ASW), mine countermeasures (MCM), and oceanography, as used by the United States Navy, Royal Navy, and French Navy. The system is used by navies to detect and track submarines and other underwater vehicles, such as those used by the Soviet Navy during the Cold War. The towed array is also used by research vessels, such as the RV Knorr and RV Atlantis, to study oceanography and marine biology, including the work of Woods Hole Oceanographic Institution and the National Oceanic and Atmospheric Administration (NOAA). Additionally, the towed array has been used in search and rescue operations, such as the MV Doña Paz and RMS Titanic disasters, with the assistance of United States Coast Guard and Royal Canadian Mounted Police. The towed array has also been used in hydrographic surveying and seabed mapping, as conducted by the National Geospatial-Intelligence Agency (NGA) and the United Kingdom Hydrographic Office (UKHO).

History of development

The development of the towed array dates back to the 1950s, when the United States Navy and Royal Navy began experimenting with passive sonar systems, with the help of NASA and Massachusetts Institute of Technology (MIT) researchers. The first towed arrays were developed in the 1960s, using hydrophones and analog signal processing techniques, as used on the USS Enterprise (CVN-65) and HMS Queen Elizabeth (R08). The development of digital signal processing techniques in the 1970s and 1980s led to significant improvements in the performance of towed arrays, including the use of beamforming and frequency analysis, as studied by the University of California, San Diego and the Woods Hole Oceanographic Institution. Today, towed arrays are a critical component of modern anti-submarine warfare (ASW) systems, used by navies such as the United States Navy, Royal Navy, and French Navy, with the assistance of Lockheed Martin and Northrop Grumman.

Technical characteristics

The technical characteristics of towed arrays vary depending on the specific system and application, as used by the United States Navy, Royal Navy, and French Navy. Typical characteristics include a frequency range of 10-100 kHz, a sensitivity of -100 dB, and a dynamic range of 60 dB, as measured by the National Institute of Standards and Technology (NIST) and the Institute of Electrical and Electronics Engineers (IEEE). The array is typically 100-1000 meters long, with a diameter of 10-50 cm, and is made of a lightweight material, such as fiberglass or carbon fiber, as used on the USS Virginia (SSN-774) and HMS Astute (S119). The processing system uses digital signal processing techniques, such as fast Fourier transform (FFT) and adaptive filtering, to analyze the sounds detected by the hydrophones and determine the location and velocity of the target, with the help of Stanford University and Carnegie Mellon University researchers. The towed array can also be used in conjunction with other sonar systems, such as the AN/BSY-1 and AN/BSY-2, to provide a more comprehensive picture of the underwater environment, including the detection of seabed and water column features, as studied by the University of Oxford and the California Institute of Technology (Caltech). Category:Sonar