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UBC-Gavia is a small untethered, underwater, robot easily deployed by 2 people from a small inflatable boat. Without a tether there is no communication between the user and UBC-Gavia when she is underwater, and missions must be pre-programmed. When UBC-Gavia is at the surface, communication with the vessel is possible via wireless LAN or Iridium satellite phone. UBC-Gavia is propelled by a single, propeller at a cruising speed of 2-4 knots, and controls her heading through active control of 4 independent control surfaces at the stern. She is powered by a 1KWh rechargeable lithium-ion battery, which provides sufficient power for 6-7 hours of run time between recharging. This results in a nominal range of 30-40km. UBC-Gavia's dynamics are equivalent to an upside-down airplane. She is trimmed slightly positively buoyant (a safety feature) and can only dive when there is sufficient forward motion and water flowing over the control surfaces (an upside-down version of an airplane taking off). This dynamic makes her ideally suited to surveying areas, as opposed to a tethered remotely operated vehicle (ROV), which behaves more like a helicopter and is well suited to investigating particular points at the bottom. An onboard suite of navigation sensors gives UBC-Gavia information about her surroundings. While underway she knows her depth, altitude above bottom, speed above bottom, and compass bearing. UBC-Gavia is equipped with a long-baseline (LBL) acoustic navigation system, which allows her to determine her position relative to two or more moored acoustic transponders over a range of about 1km. This LBL system allows UBC-Gavia to position herself very accurately (accuracy is limited to the error in transponder location-usually GPS error, ~5m) over small regions. For longer surveys, UBC-Gavia must surface periodically and update her position using a GPS antenna located in the conning tower. Using this navigation suite, UBC-Gavia is able to follow complex pre-programmed paths. Typical flight plans include straight lines, and lawnmower or radiator patterns in the horizontal, though any flight plan created by joining line segments can be followed. In the vertical UBC-Gavia is capable of flying at constant depth, flying as close a 1m above the bottom, or following a yo-yo pattern between two depths. For example, UBC-Gavia's could follow 10 equally-spaced, parallel 2km segments in a lawnmower pattern, while flying a fixed distance above bottom. In this way, UBC-Gavia could be used to map an area of the lake bottom a few kilometres in extent in a single mission. UBC-Gavia is currently capable of measuring the following parameters as she travels: chlorophyll and fluorscein dye fluorescence (Wetlabs Eco-BB3), water temperature and salinity (SBE Fastcat CTD), and velocity (using two RDI-ADCP, one up and one downwards facing), as well as acoustic (RDI-ADCP) and optical (Wetlabs Eco-BB3) backscatter. In order to put these measurements in context with what is occurring at the lake bottom, UBC-Gavia uses a high-frame rate, high-digital-resolution, colour camera with a strobe light system, as well as a side-scan sonar. The ability to measure all of these parameters simultaneously while maintaining fixed elevation above bottom provides an unprecedented opportunity to map the near-lakebed (benthic) environment. This allows for the creation of acoustic and photographic mosaics of lakebeds, over which would be superimposed maps of water properties measured by UBC-Gavia's in situ sensors. This aggregate of information would reveal patterns of lakebed characteristics in conjunction with near lakebed water properties at the basin scale.