Gozo Underwater Cave Mapping

Today gave us an opportunity to obtain some long-awaited data from a cave in Gozo. At 7am Timmy drove us to Manoel Island Yacht Marina where we met our skipper, Paul. After carrying all of the equipment on the boat, Austin, Tyler, Prof. Clark, Paul and I departed and began our 1.5 hour voyage to Gozo. Apart from some heavy chop in the beginning of the trip, the day was beautiful and the ride presented some incredible views of Malta, Comino, and Gozo.

When we arrived we ran across some tour boats which continued to come to the cave throughout the day, but for the most part we enjoyed uninterrupted access to the cave. In addition to being the first time we had mapped a cave, today was the first time we had ever used the Smart Tether. The Smart Tether is an advanced piece of equipment that contains nodes every couple of meters which use accelerometers, rate-gyro sensors, and magnetic sensors to track the orientation and position of the ROV. The Smart Tether greatly increases the accuracy of our ROV localization which in turn helps us create better maps.

In each of our experiments we took turns piloting the ROV, logging data and sketching maps, recording sonar and Smart Tether data, and working the Smart Tether. We started off using the sonar to take horizontal scans of the underwater cave, but we weren't able to get that far into the cave before running out of tether. We decided to add the 80 meter extension to our 40 meter Smart Tether, which allowed us to venture much deeper into the cave. This time we attached the sonar vertically and got some great scans with well-defined cistern-like walls. We ran across many fish, jellyfish, and even an octopus which grabbed onto the ROV. After backing out of the cave, we deployed one more time with the Smart Tether extension to take horizontal sonar scans. We ultimately got about 60 meters in before turning back. Before leaving, we made sure to shoot some underwater video of the ROV with one of the GoPros we brought along.

If all goes well, we should be able to use this data to create 3D maps of the caves using a combination of the horizontal and vertical sonar scans for mapping and Smart Tether logs for localization.

Gozo Cistern Exploration

Today, we took the ferry over to Gozo to explore 2 cisterns from last year and 1 new cistern all at the Citadel on the island of Gozo. In all three of the cisterns we visited today, the water was very murky causing no line of site (even with lasers); therefore, we only were only able to get sonar data and ROV sensor measurements at the bottom of the cisterns. Specifically, we were able to get really good scans of one of the cisterns revisited, nicknamed "The Keyhole". The scans last year from this site included some holes which were virtually filled. With the new data, we can estimate the accuracy of how well our hole filling algorithm is working.

After collecting data, our guide, George Azzopardi, gave us a quick tour of the Museum of Archaeology at the Citadel. The museum was really interesting with many artifacts from pottery to ancient utensils and figurines. After the tour, we stopped by a beautiful scenic site named "Azure Window" seen in the image below.

On the way back to the ferry, we stopped by the site that we will be visited on Thursday and Friday. The location was in a beautiful grassy field off of a very narrow gravel road. More will be posted about this place later this week.


Shortly after returning to the apartments, Chris Clark arrived! He kindly greeted us with groceries filled with delicious snacks :) Dinner was filled with many adventurous and personal stories about each of the members on the team. Another highlight of the day was submitting one of our papers to the IROS 2012 conference. This paper focused on the algorithm developed throughout the past year on mapping the cisterns visited last year, which will likely be used continually throughout the ongoing Malta Cistern Mapping Project.

Welcome All!

Welcome everyone to this years ICEX program! My name is Chris Clark and I have been one of the technical leads on the robotics side of the ICEX program for 3 years. My background includes mobile robots, controls, motion planning, and multi-robot systems. I often like to apply my ideas to underwater robots in the field. If not playing with these toys, you can find me hanging out with my family or surfing, (when my location permits). Since we created the ICEX program in 2008, the number of students and faculty participants have grown - and so has the research and cultural learning. I am excited to work with all the new participants (as well as the old!)