Low range / high resolution 360 degree sonar

[GavXYZ (Gav)]

Ahoy
I want to use a scanning sonar to assess the cross section of a culvert (pipe) in turbid water. I want to look for changes in the section.
The Ping 360 we have is great but the frequency is probably too low, the turntable too slow and the minimum 0.75 m range too large.
Has anyone come across across something with a higher frequency, short range, faster turn speeds?
If not, I wonder could I modify the Ping360.

[EliotBR (Eliot)]

Hi @GavXYZ,

• We’re currently evaluating an updated Ping360 firmware that increases the scanning speed
  • some extra context
  • for reference, a 1m range scan on the new candidate firmware (when using the ethernet configuration) currently takes ~3.5 seconds for a full revolution of 1 gradian steps, compared to ~8.8 seconds with the old firmware
• The minimum range is caused by signal noise due to internal reflections and resonance of the device enclosure, and is dependent on the transmit duration and receiver gain
  • Distances below 0.75 m might be usable, especially when the scan range is set low and the target density is very different from water, but we don’t want to claim that as a general specification because it’s not really feasible during more typical operation
  • On my desk with a 1m scan range configured the noise stops at ~0.6m, but a strong target may be detectable as close as 0.3m away, although I’m not certain whether that noise reduces faster or slower when the device is in water
    
    
• The Ping360 has a variable transmit frequency (which is controllable between 500-1000 kHz through the advanced device settings in Ping Viewer)
  • It’s worth noting that the transducer is tuned to 750 kHz, so straying from that reduces both the transmit and receiver efficiency, which results in weaker responses but also faster die-down of the internal reflections

@GavXYZ

I wonder could I modify the Ping360.

If the available settings and options aren’t sufficient then you’ll most likely need to use a different device. The transducer head is oil-filled and has some potted components, so modifying its internals is unfortunately not simple.

[GavXYZ (Gav)]

That’s great Eliot. Thanks for your considered response.