B-Seal specification

The Center for Marine Environmental Sciences MARUM has procured a Deep Water AUV with a standard working depth of 5000 m. The main goal of the University is to have a universal tool capable to be operated in a scientific environment with changing demands in terms of sensors payloads and operational aspects. The basic task should be high precision seafloor mapping with a fully integrated multi beam sonar system.

General vehicle specifications

Length: 5.50 meters
Diameter: 0.74 meter
Weight: 1.3 tons
Depth rating: working depth down to 5000 m
Vehicle body: Glas Reinforced Plastic
Pressure housings: Anodized Aluminium
Battery: Li-Ion batteries, 14 modules of 1kWh each
Endurance: > 19 hrs (with standard payload)
Range: > 100 km (with standard payload)
Speed: 0.25 – 2.4 m/sec
Operating Speed 1.5m/s

The navigation is a critical system for an autonomous vehicle.
It consists of the following devices:
- IXSEA PHINS Inertial System
- DGPS
- RDI 300kHz Doppler Log
- Obstacle avoidance sonar (Kongsberg 1007 series)
- Depth Sensor (Paraoscientific Digiquartz)

The Vehicle is controlled by the VCC (vehicle control computer).
The programmed mission and the parameters for the navigation are maintained by the VCC.
The VCC controlls the whole system status, error messages, the actuators like thruster and planes, Energy management and also the emergency system.
The emergency system consists of different measures related to the level of emergency. The bottom avoid routine is carried out when the vehicle reaches the minimal navigation altitude. The vehicle tries to pitch up to stay above the minimal navigation altitude. The vehicle will stop the current mission If this does not take effect and the vehicle reaches a critical altitude. The vehicle will react with a release of the drop wheight in case of a short cut on the main Power bus or other critical failures. The drop wheight mechanism can also be triggered by the operator via the acoustic link even if the main power supply is dead.
There is one optical flasher (Benthos) and a radio beacon (Benthos) installed. They have a dedicated battery and are activated when the AUV is on the surface.
The vehicle will report its Position via Iridium Satellite when on the surface.

The standard paylod is the RESON 7125-B Multibeam Sonar.
It works at 400kHz with up to 512 beams.
The multibeam uses the attitude like roll, pitch and heave, heading etc. readings from the inertial system.

Additional Sensors are:
- SeaBird SBE49 CTD

integrated during spring 2009:
- WetLabs FLNTURTD Fluorometer and Turbidity sensor
- IXSEA Echoes 5000 AUV Sub Bootom Profiler
- Benthos Dual Frquency Sidescan Sonar (SIS 1624)

Deck LAN Cable
The user has access to the recorded Data and the whole vehicle via the deck cable (100MBit/s LAN). The whole system can be controlled and all payload computers like the RESON IPC or the payload computer for the Sidescan and the Sub-Bottom Profiler can be accessed. The user has also full access to all interfaces of all sensors like GPS, CTD, Main battery modules etc. for tests and configuration of the sensors.

2.4GHz Radio Link
The vehicle can also be accessed via the Radio link. The purpose of this link is the control of the AUV during launch and recovery. The operator can switch on all sensors, perform all necessary test before starting the mission. The operator will pilot the vehicle manually to the starting point of the mission and will bring the vehicle back to the ship for the recovery.
The amount of traffic is limited on this link, all data retrieval or remote desktop operations should use the Deck cable link.

Acoustic sub sea link
A Sercel Orca Modem is used to exchange information with the AUV while it is submerged. The operator gets the status of the mission, speed, heading and position of the AUV. The operator can also abroad the mission, release the drop wheight or start another section of the programmed mission via the acoustic link.

Posidonia / Gaps Beacon
The Beacon will be triggered by the ship borne Posidonia / Gaps system.