this is multibeam. they are using side-scan sonar as the primary search mechanism. it will emit sound. as it bounces off of the sea floor, the sonar receives that sound and uses the reflection from the sea floor to build an image of what's on the sea floor is. >> is it easier to do deeper in or higher up. >> it comes out good when you are deep. you have a nice stable platform and the sonar imagery can be crisp. the challenge is getting that sdoe sonar down deep. that is difficult. you have to put it on a vehicle and it has other components and that's where the challenge is. >> let's look at what the data looks like when you get an image of this sound. that's pretty much what you are doing, right? >> right. we have been building a map over the course of the day here. you can see we have done this lawn mower pattern and going back and forth. here's where we are now and we will add to it as we go. in realtime we are able to see where we are, reconstruct the plan on the fly based on what we