Phased Array Technology - Interphase PC/View Operation Manual

Forward scanning sonar, for windows

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Troubleshooting manual (5 pages)

Table Of Contents

Table of Contents

typically show only those targets that are within

Three Fixed-Beam System, Looking Down and

this main beam width. A large beam width will

to Each Side of Boat

show targets from a larger underwater area, but

suffers from lack of resolution. That means that

although several targets may be in the beam

width, the user can only determine their distance

from the transducer, not their lateral position

within the beam. For example, if one fish target

is 10' below the boat at the far right edge of the

beam angle, it will show the same display as if it

were 10' below the boat at the far left edge of the

beam angle. In addition, if fish are present at

exactly the same depth but at different sides of the

underwater beam, the transducer will receive

echoes from both fish targets at the same time and

the display will only show a single target. This is

a serious limitation to the conventional

technology.

To get around this limitation, several

manufacturers have resorted to adding more

Bottom

piezoceramic elements to the transducer, each

pointed in a different direction. By selectively

using each piezoceramic element the transducer

has the ability to point or look in as many

different directions as there are piezoceramic

elements. After approximately four elements,

however, the transducer housing starts to become

physically large and cumbersome. To date,

manufacturers have put as many as five separate

elements into the transducer to enable users a

view in up to five different underwater directions.

For the future, Interphase believes that this

multiple fixed-beam approach has serious

limitations, especially for use in more advan ced

products where maximum underwater coverage

and resolution are important.