Search results
Results from the WOW.Com Content Network
Garibaldi near Wreck Alley, San Diego, CA. The Ingraham Street Bridges spanned Mission Bay. When they were replaced in 1985 the old bridge pilings and roadway were dumped in the Wreck Alley area. These were huge pieces of bridge, roadway, railings and pillars, all jumbled together. There were many fish and various crawling sealife as well.
While the erosion process of turbidity current erosion which once carved out the submarine Monterey Canyon is well known, the cause of the great depth and length of this canyon, obviously carved out millions of years ago, and the unusually large size of the sedimentary deposit (fan) at its underwater mouth 95 miles West of Monterey, have all been a cause for some speculation.
The baseline stations are first deployed in the corners of a work site. Their relative position is then precisely measured using the AquaMap system's automatic acoustic self-survey capability. For geo-referenced operations, the baseline positions are surveyed by differential GPS or a laser positioning equipment (total station).
Each GIB determines the precise time of the received signal and transmits this time to the deployment ship in near real time. A command and control system located on the deployment and recovery ship combines the GPS data and acoustic timing information to triangulate the impact location and determine the exact impact time in near realtime.
A drifter (not to be confused with a float) is an oceanographic device floating on the surface to investigate ocean currents by tracking location. They can also measure other parameters like sea surface temperature, salinity, barometric pressure, and wave height. [1] Modern drifters are typically tracked by satellite, [2] often GPS.
One of the complications of this class of underwater survey is the relative difficulty of establishing a baseline, or an accurate position for the ROUV, as GPS signals do not propagate through water. In some cases a physical line has been used, but sometimes a baseline can be established using sonar transducers set up at accurately surveyed ...
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
GPS intelligent buoys (GIB) systems are inverted LBL devices where the transducers are replaced by floating buoys, self-positioned by GPS. The tracked position is calculated in realtime at the surface from the Time-Of-Arrival (TOAs) of the acoustic signals sent by the underwater device, and acquired by the buoys.