Beam Reach

Localization Headaches

I’ve been spending a large part of my time doing analysis trying to localize calls in Ishmael. Since I never had a situation where the entire group was social. I have to localize the calls from each social period to see if they came from the social group or not. The way you do that is by opening the file in a program called Ishmael, imputing your hydrophone data, selecting a call, and pressing localize. When you do that Ishmael looks at the four channels that were recorded and calculates the difference in time it took for the sound to reach the four hydrophones. It can then use this to calculate the location of the call.

Unfortunately Ishmael is not perfect and neither are our recording conditions. Since the ocean is a noisy environment with lots of background noise there are times that it can’t distinguish above the background noise and will give you some strange answer that sometimes invloves the animal being millions of miles away. Also, if a call is made directly in front or behind the array it can’t localize well because the sound waves are coming straight on. Because of this I have a lot calls which can’t be localized well if at all.

All in all this is doing nothing to make the frantic last week of analysis and paper writing easier. That said, it is slowly bit by bit getting done and I feel good that I will be able to pull everything together and be able to have a good presentation ready come Saturday morning.