ambience: DEPTHX ambience
To explore and map the worldâ€™s deepest lakes and sinkholes, scientists have created a self-navigating robot. But how does the device know to where go when no other robot has gone before? Iâ€™m Jim Metzner and this is the Pulse of the Planet. Nathaniel Fairfield is a graduate student at the Carnegie Mellon University Robotics Institute. He helped to develop the DEPTHX robotâ€™s self-navigation system. In order to complete its mission, the DEPTHX must both keep track of where it is and accurately map its surroundings.
â€œThe problem is that we neither have a map because weâ€™re exploring into a completely unknown environment, nor do we have a really clear idea of exactly where we are.â€
The DEPTHX robot explores its underwater surroundings with the help of multiple sonar units. But why not use something simpler, like a GPS system to help keep track of the robotâ€™s location?
â€œIf we had a GPS or something like that, it would tell us, you know, â€œYou are here,â€ all the time, and thatâ€™s great. Thatâ€™s what you do if you possibly can, absolutely use GPS. But when weâ€™re underwater, radio signals donâ€™t travel at all underwater, really, except for very low frequency ones that are pretty much useless. So, we donâ€™t have GPS. We donâ€™t have a given global position, so we have to put it together. We have to try and build a map as weâ€™re going along, and then, we have to use that map at the same time. So, itâ€™s as if weâ€™re walking down a tunnel, drawing the lines that we see behind us, and then looking forward and saying, â€œOkay. It looks like the walls continue on ahead. Letâ€™s draw those lines on a little bit,â€ and then, we take 10 steps forward, and we look back, and we see, â€œOkay. The walls are there, and I thoughtâ€you know, lining yourself up with where you thought you thought the walls were and then putting the new information that youâ€™re collecting in front of you. So, that starts to get into technically how this dataâ€™s represented on the robot.â€
Pulse of the Planet is made possible by the National Science Foundation, with additional support from NASA. Iâ€™m Jim Metzner.