What model of SSS would be suitable

[Rob]

Hello folks,
I'm looking for SSS which could imagine-detect 10cm size objects (trash). What model could do it and what technics are used for such purpose.
Any recomendations are very appriciated

thanks,
Rob

[Rob Morris]

Re: What model of SSS would be suitable

Rob,

Edgetech has Side scan systems that can resolve objects smaller than 10cm.( see below) The Portable 4100 system comes with a target logging program that will calculate the position of the objects imaged with the sonar.


272TD Towfish - Beamwidths and Target Resolution @ 100m.
The 272 One Way Beamwidths are
390Khz = .47degrees
105Khz = 1.8 degrees
and the Two Way Beamwidths are
390Khz = .38 degrees
105Khz = 1.44 degrees
The resolving ability of a side scan sonar is dependant primarily on its along track beamwidth and
receiver bandwidth. To provide a definition for resolving power we state:
Definitions:
Resolution (in a sonar/radar system context) is a measure of the ability of the system to
distinguish between two closely separated targets. High resolution systems can "resolve"
two close targets better than one with poor resolution. This ability is often measured or
quoted in meters.
Thus:
The resolution of a sonar is its ability to determine the presence of two small objects
separated by a distance X. If the resolution of the sonar is greater than X, the 2 targets
will appear as one in the sonar image. If the resolution is X or less the target should be
resolved into 2 distinct targets in the image.
For this purpose we use the following rule to determine if the targets will be resolved.
"The resolution of the sonar is twice the two way 3 dB beamwidth."
390Khz
At 100 m, the along track, two way beamwidth is 0.66m. Using the above definitions and
reasoning the resolution of the 272 HF channel is 1.3 m
105Khz
2 way Beamwidth in meters = 2.52m, so the resolution is 5.0 m.
Pings on Target
The above discussion does not include the effects of sampling the image. When the image is
sampled, this may further degrade the ability to resolve the 2 targets.
The Sampling of the image in the along track dimension is determined by the Ping rate / Tow
speed relationship.
Experimental evidence shows that to sample a dataset acquired with a resolution of Y meters
without loss of resolving ability, the sample spacing should be 0.5 x Y or less. Note this is the
minimum limit, and experience shows that higher density samplings significantly increase target
detection.

If you need more information contact me directly.

Regards,

Rob morris

Edgetech Customer Service

[Mark]

Re: What model of SSS would be suitable

Rob,

So what's the range resolution of the 272?

Mark

[Rob Morris]

Re: What model of SSS would be suitable

Mark,,

Due to beam spreading the along track resolution depends on the range. The along track resolution of the 272 at 100m is about 1.3m., .66m at 50m. The accross track resolution is