DESCRIPTION

The EdgeTech 4700-DFX Dynamically Focused Multi-Pulse Side Scan Sonar combines in one system, Multi-Pulse technology for high speed surveys, along with dynamically focused transducers for high resolution imagery at long range. A secondary conventional frequency (300 kHz) is also provided for search capabilities. The result is a low cost state-of-the-art side scan sonar system.

Conventional side scan sonars have always been defined by the limitation of having only one ping in the water at a time. Typically this has kept the speed of survey below 5 knots to ensure 100% coverage.

Based on EdgeTech’s Full Spectrum Frequency Modulated (CHIRP) pulses, the 4700-DFX uses proprietary signal coding to place up to 4 pulses in the water at the same time. This translates into a 4 times increase in survey speeds while still maintaining 100% bottom coverage or a 4 times increase in hits on the target for improved imaging at standard survey speeds. The same simplicity of a conventional single beam side scan system, all we do is ping up to four times faster!

The resolution achievable by conventional sonars is always a compromise between low frequency for long range performance, and array size, which limits the along track resolution. The along track resolution is, at best, equal to the physical array length, and degrades even further with range.

Traditional, single element arrays are essentially focused at long range, providing sub-optimal behavior at shorter ranges. By using a physically concave array to focus the acoustic beam the resolution can be improved. However, such transducers have a reduced depth of field and as such are not practical for use in side scan sonar. By using a transducer comprised of multiple, individually accessible elements, electronic dynamic focusing techniques can overcome this limitation by changing the effective shape of the array during the receive cycle. This provides an along track beam width substantially less than the physical array length. The full array length can then be exploited at long ranges to provide extremely small beam angles of 0.1degrees for superior long-range resolution.

Combine the multi-pulse technology for speed, and dynamically focused transducers for resolution, and you meet or exceed the specifications of a multi-beam side scan sonar. This is achieved without some of the limitations of multi-beam side scan such as degraded images in turns.

The 4700-DFX system is also ideally suited to AUV and ROV installations and employs the common control and data interface of all EdgeTech's Full Spectrum® family of products