Sensors
Sensors are located in a structure called the scientific payload. The following sensors would be useful for us:
CTD(Conductivity, Temperature and Depth Sensor)
Passes current through the water. The conductivity measured is converted to a measure of the salinity. The thermometer is an electronic thermometer, which should have a very large range. It has a wet end, that is located in the free flooding space of the AUV, and a dry end. Usually, it requires a small pump to provide flush water. It is about 24.8 cm long and 7.7 cm in diameter.
ADCP(Acoustic Doppler Current Profiler)
Collects data on tide, current and mean depth. It works as a navigational instrument and current meter all in one. It is 10.2 cm in diameter, made of titanium, and is 20 cm long. Its range is about 50 meters from the vehicle. It consumes a power of 0.5 watt while operating.
Laser scanning
Similar to radar using laser light. Light of green frequency used as it can penetrate greater distances in the murky waters.
Side Scanning Sonar
Sends out a fan of sound waves, and allows a map of the texture of the underwater area to be made. You need two of them, one on the port and one on the starboard side of the AUV. It can measure to a distance of 40 meters on either side of the vehicle. It is cylindrical, and has a length of around 38 cm. Again, like the CTD it has a dry element, its electronics and processing units which are stored in the pressure hull. It should be located further from other sensors to prevent interference of transmitted and received signals. Usually, the Side Scan Sonar is partially recessed in the vehicle, and is mounted forward of control surfaces to minimize turbulent flow over the transducers.
The Three Sisters mapping AUVs should have hydroplanes, because in order for the system to work efficiently, the AUV must not move around too much.
Sub-bottom Profiler
This provides high resolution images of the layers below the seabed, and has a penetration of 5-100 meters into the sea-floor, and a 100 meter range. By using backscatter it allows an image to be built up of the bottom, and it also has a wet end and a dry end. Wet-end is mounted in the flooded section of the AUV pointing downwards. It is synchronized with the multi-beam and sidescan sonar in order to minimize the effects of interference. Connections are made simply by ethernet and normal ports.
Multi-beam sonar
This measures the depth of the ocean from the AUV. It is also called a "swathe bathymetry sonar." It has a 150 degree wide swath and a frequency (sampling) of about 240khz. Measures direct depth, enabling complex underwater features to be mapped with precision. The swath range is over 500 meters wide. Range resolution on a picture produced is about 1.25 cm. The length of the instrument is 27 cm, and it has a diameter of 32 cm. Its weight is 26.8 kg in air, and 4.8 kg in water.
ph Meter
Inclinometer
Measures changes in angular alignment, so that the AUV can always ensure that it is traveling upright.
Camera
Mounted with lasers to increase its range, SIT camera (Silicon Intensifying Tube).
Leak Detector
Ensures there are no leaks in the AUV. If there are any leaks the AUV will not launch. This is located in the pressure hull.
Altimeter
Measures depth. Probably not really needed because there are enough depth finders already.
Transmissometer
Measures how much light passes through water and indicates the amount of substance dissolved or suspended in the water. Good for Superman.
Fluorometer
Measures the amount of fluorescent radiation from a sample exposed to monochromatic light. It provides an indication of the amount of chlorophyll.
Flow injection analysis
Water is sucked in and concentration of trace elements like Fe measured.
Obstacle Avoidance
Multi beam sonar able to classify and detect obstacles, and actuate a series of maneuvers to avoid collision. ( 8 - 10 beams) Laser scanning can also be used for increased maneuverability. It only works for short distances though.