Wavefront Systems has published an insightful article emphasizing the meaning of selecting the appropriate sonar payload for mine countermeasure operations, showcasing the benefits of its Solstice side-scan sonar.
Multi-Aperture Sonar (MAS) is meticulously engineered too conduct effective surveys that support mine detection, hydrographic studies, salvage operations, search and rescue missions, and the removal of unexploded ordnance.
Choosing the right technology is crucial, notably in certain applications. Retired Commander Justin Hains MBE from our partner company Forcys elaborates: “in mine countermeasure operations, the sonar payload is a pivotal design decision. An effective sonar equips MCM teams with actionable intelligence. Conversely, a poor selection can lead to numerous false alarms, each requiring inspection by a remotely operated vehicle or incurring diving costs.”
When dealing with side-scan sonars and Synthetic Aperture Sonars (SAS), engineers face the challenge of optimizing performance in particularly challenging acoustic environments. This is especially true in shallow waters, such as tidal zones and riverine settings. Factors like high-order multi-path reverberation, fluctuating sound velocity profiles, complex bathymetry, baseline decorrelation effects, and a scarcity of stable platforms contribute to unreliable sonar performance at shorter ranges.
To tackle these performance challenges associated with conventional side-scan sonars, we developed Solstice.
how Solstice Addresses Acoustic Challenges in shallow Waters
We engineered a multi-aperture array to enhance the signal-to-noise ratio, extending the operational range compared to other sonars at the same frequency.Though, it became evident that longer ranges in shallow, coastal waters remain vulnerable to multi-path reverberation.
Dr. Rob Crook, Research Director, states: “The primary noise source for all side-scan sonars in shallow waters is ‘multi-path’ reverberation.This type of noise arises when multiple acoustic pathways scatter from spatially unrelated areas of the underwater habitat,yet return to the sensor with identical travel times. The inability of any ‘2D’ (range, bearing) sensor to differentiate between these simultaneous pathways results in a loss of contrast. Our Multi-path Suppression Array Technology (MSAT) is a physical array-based solution that provides swathe coverage typically associated with wide elevation beam-widths while maintaining the shadow contrast of very narrow beams. MSAT enables high shadow contrast all the way to the sensor’s maximum range while ensuring high-quality imagery near nadir.”
Mechanism of Action
Contrast is vital for distinguishing targets from thier surroundings. Additionally,Solstice employs dynamic focusing to ensure that images retain the highest possible resolution relative to the sensor’s position. This means that as the distance to the target decreases, the resolution improves. At greater distances, the interpolated real-time imagery significantly enhances human visual interpretation.
advantages of Solstice
The design features and other meaningful benefits of Solstice provide users with considerable advantages:
Predictable Mission outcomes
Solstice is user-kind, simplifying mission planning. The area coverage rate increases with speed while maintaining a constant range. This allows for effective plotting of survey routes and monitoring of the target area, making the survey results more predictable and manageable.
Reliable Results
SAS systems are often sensitive when mounted on unstable platforms or operating over complex seafloor conditions. Dynamic changes, such as sediment shifts, can degrade data quality, perhaps leading to a complete loss of micro-navigation information. The worst-case scenario is the SAS reverting to standard side-scan mode, where low operating frequencies render the data ineffective for mine detection. Solstice remains unaffected by these dynamic changes, delivering high-definition data even in challenging environments.
Performance in High Currents
Unlike SAS, and similar to other side-scan systems, MAS’s range is primarily limited by the ‘crabbing angle,’ yet image quality is preserved across the entire swath.
Efficiency in Shallow Waters
Conducting operations in confined and shallow waters (depths of 20m to 30m) poses challenges for SAS systems and lower frequency side-scan sonars. As range diminishes, multi-path effects from surface returns can significantly impact signal-to-noise ratio performance.This common issue can compromise up to 50% of the swath for many side-scan sonars. In contrast, solstice MAS typically experiences an impact of less than 10%.
Seamless Integration
solstice can be easily integrated with other imaging technologies, such as Voyis Laser Imaging and Camera products, as well as EIVA mission planning software.
