How is the angle of a return echo determined?

[M1200AK]

Hello everyone! I just joined, tried to edit my profile but the system says I can't access that feature, but I do have a question that I hope can be answered by someone on here.

How does a side scan sonar determine at what angle a return echo came from (off to either side) in order to know where to place it on the visual display?

From what I understand a single pulse is transmitted from a transducer (left or right side) and then somehow from that single pulse the system is able to differentiate at what angles different echos are returned from. The transducer isn't being physically swept through an arc like a RADAR antenna in order to determine the angle.

How does it do this? Is frequency modulation involved (similar to how some RADAR systems operate)? Can someone explain how it's done? Links to good explanations (I've been unable to find any myself)?

Thanks!!

[Cruiser]

not sure what angle you are asking about?
The sidescan sends out a narrow beam like a single line, the return echos are placed on the line based on time it takes to return, either closer or further out the line. There is no angle to calculate.
The next pulse does the same and over and over to display the image created by the sidescan moving along the bottom.

[wrvond]

Unlike a radar system which has a single emitter/receiver, sonar transmitter/receivers are made up of several elements called staves. The audio frequency pulse is transmitted through all the staves at once, then the system shifts to receive mode. As the echo returns the angle is determined by the phasing of the signal. It will, for example, strike the bottom rear staves first, then the bottom middle, then the bottom front. This will indicate the direction of the target. Signal delay and strength will determine target range.
It's been several years since I worked on sonar systems, but I'm pretty sure I'm remembering that correctly.