Humminbird Side Imaging Forums
General => General Discussion => Topic started by: Bob B on January 16, 2012, 08:05:03 PM
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Greg,
Could you give us a quick lesson on ping rate?
What are the factors that affect it? Is it both depth and SI range? Are there any certain increments of SI range that change the ping rate?
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If the boat is moving very fast and the rate that the sonar unit is pinging is slow, then the number of times sound is bounced off the seafloor in the area covered is fewer than if the boat was moving slowly while the unit was set to a high ping rate. Also, if the area being covered is very deep, then the boat must move slower over that area, or the unit must use a higher ping rate, in order to achieve an equal quality image as to images at shallow depths because it takes longer for the sound pulse to return to the transducer.
The ping rate is also limited by the speed of sound in water, because with most multibeam systems the transducer must wait to receive the last ping sent before generating the next one (i.e., there can only be one ping in the water at a time). This operational constraint sets an upper limit on the ping rate for a given water depth and swath width combination.
Chuck
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I’ll add to what Chuck stated:
Increasing the ping rate can show more (weaker) targets which can help in deeper water or high-noise environments (like a fast moving boat) as it will help with tracking the bottom. The down side of increasing the ping rate is that you lose target separation.
The ping rate that we use is determined by the longest range being transmitted/received. This is typically the side range, but it could also be the 2D sonar range. I do not know the ping rates for any certain settings.
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I dont see a standard for ping rate. It is all dependent on depth and range...
But I can see where the guys who lose bottom depth display can have the ping rate affected if not on manual depth....
Chuck
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Thanks for the feedback guys