Day 3

Wednesday.

Back to the field for another day of AUV ops. Today, we also had some fun with an ROV (Remotely Operated Vehicle), the VideoRay.

Here, we do our part as environmentalists and retrieve a Cola can from the depths.

Doug and I made up the "Boat Team" today, and were responsible for launches and recoveries of the AUV.

We also tested the ping locator by taking the spare and bringing it to different distances from the dock. We found it was very directional.

Other things I discussed today:

1)Acoustics. Especially with Tom Weber. There is a Sound Velocity Sensor on the Gavia which takes readings of the water column to calculate the water's sound velocity. The velocity is taken into account when the sonar data is processed. Temperature, salinity, and some other factors change the speed of the sound in the water, so thermoclines are important features to map. Also, the Navy knows a lot about these features because they can use them to hide submarines. The layer can either prevent sonar from detecting the sub, or from the sub sending out its own sound signals. Another basic thing I learned is that we use sound and sonar because electromagnetic light and radio waves will not penetrate into water. What Tom has done with his buoys are to use a program like MatLab to make and translate electric pulses into an acoustic signal using an acoustic modem. These acoustic pulses can be used to communicate with the Gavia.

At the end of the day, we held a classroom session with Alex Forrest.

Things we learned in the classroom:

- Pre-mission setup (last minute checks)

- post-flight checks

- data retrieval

- analysis of scientific payload data

- mission planning – toolbar to choose things like lawnmower pattern. also make a waypoint (start and end) or line.

- power status of the sensors – some take a short time to power up while others take a longer time (3 minutes). - Must give enough time to boot up and then check that they are turned on.

- upon return of the AUV – is there data? go into the file folders. Download log files and check navigator/ mission manager/ captain files.

There are only 14 max Gavia units…this is an elite crowd that I’m in.