Can Active SONAR Be Used to Create False Reflections for Avoiding Torpedo Attacks?

When an incoming torpedo uses active SONAR to locate a submarine, it's natural to wonder if the submarine can use its own active SONAR to create false reflections and mislead the torpedo. However, as we will explore, this approach is not as effective as it might seem. This article delves into the challenges and limitations of using active SONAR for this purpose, drawing on the specific frequency ranges used by different SONAR systems.

Understanding SONAR Frequencies

Sonar (Sound Navigation and Ranging) technology relies on the principles of sound waves and their interactions with the environment. The effectiveness of sonar systems can be significantly influenced by the frequency of the sonar waves. In the context of submarine warfare, there is a clear distinction between primary search (PS) and targeting active frequencies.

Primary Search (PS) Frequencies: These are typically in the 2-4 kilohertz (kHz) range. These frequencies are used for wide-area searches and detection. They provide broader and less detailed information about the presence of objects in the water but are not designed for precision targeting.

Targeting Frequencies: For close contact work, aiming for a torpedo or ramming a torpedo into a ship, the frequencies are much higher, ranging from 20 kHz and above. These higher frequencies allow for more detailed and accurate targeting.

Limitations of Mimicking Torpedo Signals

Even if a submarine were capable of generating signals that could mimic the sounds coming from a torpedo, the approach would still face significant challenges. The key aspect of torpedo guidance is direction. Torpedos use directional sensors to track and home in on their target. False signals would provide no directional information and could actually exacerbate the tracking problem.

For example, attempting to spoof the sounds coming from your own submarine instead of the torpedo would confuse the system in ways that could be detrimental. The torpedo’s guidance system is designed to interpret the direction of the sound, and spoofing with your own signals would not provide this information, thus making it more difficult for the torpedo to home in on anything.

Countermeasures Packages

The military has developed various countermeasures packages for submarines. These packages can eject launchable decoys that emit sounds and generate bubble images, which to a passive sonar operator, might look like a submarine. However, these decoys are carefully designed and not directly related to active SONAR. Active SONAR signals do not behave similarly to radar, which can produce false signals and jamming through the jumbling of electromagnetic waves. Sound waves in underwater environments do not have the same interference properties as electromagnetic waves.

The effectiveness of these countermeasures largely depends on the sophistication of the blind and active sonar systems. Effective countermeasures can create echoes that make it difficult to distinguish between the signal from a submarine and false signals. Nevertheless, the use of active SONAR to create false reflections is not a common or recommended approach in submarine warfare due to the aforementioned limitations.

Conclusion

In summary, while the idea of using active SONAR to create false reflections for torpedo avoidance sounds promising, it is not a practical or effective strategy. The frequency ranges used for primary search and targeting in SONAR systems are inherently different, and the directional information used in torpedo guidance cannot be easily spoofed by attempting to mimic torpedo signals. Instead, advanced submarine technology relies on highly specialized countermeasures packages to provide a more reliable means of protection against incoming torpedoes.

Acknowledgments

This article is based on general principles of sonar and submarine warfare. It is not intended to be a definitive guide for military operations. For further information, we recommend consulting the latest literature and expert opinions in the field of submarine technology and military sonar systems.