Technology Projects > Ocean Electronics > Introduction

Introduction


Ocean Electronics group is focused in developing new ocean observation technologies. The group is involved in the development of profiling floats, Drifter with INSAT Communication, C- profiler, WXCTD, Ocean Glider, Self sustainable profiling systems using Ocean thermal energy and Fish cage ethnologies.

Some of the major projects are indigenization of Tsunami system using bottom pressure recorder and development low cost met buoy.

Autonomous Underwater Profiling Drifters (AUPD).

The Autonomous Underwater Profiling Drifters are used for measurement of temperature and salinity profiles in Oceans. The AUPD is designed for profiling up to 2000m and DAUPD is designed for 5000m.

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Autonomous Underwater profiling drifters 2000m and 5000m system

Indigenization of Drifting Buoy with INSAT Communication

The drifting buoy (DB) with INSAT communications (Pradyu) a floating device deployed at sea to collect the Meteorological/Oceanographic informationsuch as the Sea Surface Temperature (SST), Atmospheric pressure, Salinity. The data is time stamped with GPS Position forwarded to shore station using INSAT communication satellites. The Ocean Current measurement is derived from the GPS position data obtained.

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The technology is transferred to 4 Indian industries to manufacture and support Global Drifting buoy program.


Mixed layer current trajectories of indigenized drifters deployed during the year 2011-2015

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Mixed layer current trajectories of the trial produced drifters (DB33-red), DB34-blue), and DB35-green) deployed in the southern Bay of Bengal at 89°E and 3.8°N on 14 March 2020. The black tracks represent drifters deployed under GDP (The WMO ID of the GDP drifters used in this study are 2301627, 2301628, and 2301629).

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TLA signing on DB technology at NIOT on the august presence of Secretary MoES Dr.Rajeevan

Development of “C” profilers

C-Profiler is an underway automated system to collect continuous near vertical data profiles in Ocean Mixed Layer (OML) while ship is on move. C-Profiler uses a tow winch, tow fish, CTD sensor, GPS module and a controller. Tow fish is instrumented with CTD sensor. Tow winch is controlled by using a computer with customised software made in-house to operate the tow fish to attain reconfigurable minimum and maximum depths for each profile. The software generate real time plots of ocean parameters, calculates the distance taken by the ship to complete a profile and angle of verticality. Data comparison was done with the on-board standard CTD with correlation graphs and found close match.

Advantages of C-Profiler over the existing underway and conventional CTD profilers are as follows

  • There is no need of lifting the probe to deck for data retrieval.
  • We can take real time on site decisions for specific profiling depth without lifting the probe to deck.
  • Sensor heads are exchangeable which enables to take various ocean parameters without extra profiler.
  • C-Profiler is economical with a light weight tow body
  • This system creates a separate file for each profile that contains GPS data (location), CTD data, distance between two consecutive profiles and angle of verticality of each profile with normal.
  • The alarm (sound signal) acknowledgement when towfish reaches the designated minimum and maximum depths
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    C- Profiler tested in Bay of Bengal.

    Drone Technology Adaption for Ocean Observations.

    Observations at the shallow water plays major role in studying water quality monitoring purpose because they are sources for deep water pollution, migration of eco system and marine habitat in coastal waters. It’s very tough job to monitor highly dynamic shallow waters where deep water waves entries into shallow water zone. There are many water quality measuring systems exits such as vessel based data collection, coastal moored buoy, human based water sampler method, autonomous under water vehicle & autonomous surface vehicle, still to cater the high resolution measurement requirements of coastal regions, Ocean Electronic group has devised a Drone based high resolution water quality monitoring system (WQMS). It consists of Drone as carrier of instrumentation payload which is augmented with series of high resolution sensors for monitoring Oceans temperature profile at shallow depth, Conductivity, pH, DO, turbidity,chlorophyll-a concentrationand partial CO2.

    As part of adapting a drone (Unmanned Aerial Vehicle)for ocean observation applications, Ocean Electronics Group recently conducted a field study on the drone stability (static & dynamic) with CTD sensor and instrumentation payload using a 10 kg lifting capacity drone with the external industry. This field study provided a suitability and confidence in adapting a drone (Unmanned Aerial Vehicle) for ocean observation applications.

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    Sequence of operations performed while dip test at lake

    The drone performance and stability is observed to be excellent fortype of instrumentation payload& measurement schemes. Further field study and ocean data collections will be performed upon the procurement of suitable drone for the shallow water regions water quality monitoring applications by NIOT.

    Development of Ocean Glider

    Ocean Gliders like the air gliders consume very less energy to travel ling distances, due to this, they can use most of the energy for performing science missions for survey and measurements. This puts gliders in to forefront for performing long duration oceanographic missions, apart from AUV’s and ROV’s. Buoyancy and Centre for Gravity control helps the gliders to perform dive and accent manoeuvres.

    Underwater gliders are a recently developed class of autonomous underwater vehicle (AUV) driven by buoyancy changes to fly along saw-tooth trajectories through the ocean. Gliders quickly have become the AUVs with the highest endurance and longest range. They are able to sample the ocean interior at comparatively low cost because they can operate independently of ships for the better part of a year under global remote control, reporting the observations they collect in near-real time. They are well suited to intensive, regular, and sustained observations of oceanic properties that are readily measured by electronic means. Their long range and endurance come at the cost of traveling slowly, which affects their ability to navigate through the ocean.

    National Institute of Ocean Technology, Chennai (NIOT) introduced a revolutionary new mobile sensor node, an underwater glider, “Slocum G2 glider” (“Barathi”, manufactured by Teledyne Webb Research, USA) for high spatio-temporal resolution measurement in the BoB in September 2013. NIOT also conducted a long duration operation about four months in the BoB in April to August 2014.

    The deep sea is the new frontier for mining, oil exploration, and other industrial activities as they leave the continental shelves for areas miles beneath the ocean surface. Along with these come greater dangers to the environment, this will require constant monitoring. To provide high spatio-temporal observation of the upper surface layer in the deep sea, National Institute of Ocean Technology (NIOT) is in the process of developing sea Gliders for deep-water applications.

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    Conceptual design of the Sea Glider and filed deployment

    Development of Open Sea Fish cage Technologies

    The contribution of Indian fish to the food basket of the world has been substantial. India is the second largest fish producing and second largest aquaculture nation in the world. India has about 8118 Km. of coastal line and nearly 2 million Sq Km of EEZ and half a million Sq Km. of Continental Shelf. From these marine resources, India has an estimated fisheries potential of 4.41 million tonnes. Similarly, we have 3.15 million hectares of reservoirs, 2.5 million hectares of ponds and tanks, 1.25 million hectares of brackish water area, cold water resources of hilly states and all other inland fishery resources offer a production potential of about 15 million tonnes , Against this potential ,Currently fish output in India is estimated to be 13.4 million tonne(MT) of which 32% comes from marine sector and Mission Mariculture -2022 aimed at meeting the fish demand of 20MT by 2022-23 under PradhanMantriMatsysSampasaYojana ( PMMSY) supporting “ Blue revolution“

    The Blue Revolution, with its multi-dimensional activities, focuses mainly on increasing fisheries production and productivity from aquaculture and fisheries resources, various fish cage technologies are to be developed in the area of the open sea submerged rigid fish cages system and its feeder system which can support Mission mariculture under the blue Vision as problems encountered in the present open sea floating cages during bad weather condition shall be overcome with these fish cage technologies and shall be help for the Indian societal activities

    Objectives

    • To develop open sea submerged rigid cage system to support the blue vision
    • To develop the sub- sea feeder system for the open sea submerged cage system
    • To develop the bio-mass estimation and to implement in these open sea cages
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    Fish Cage technologies: Submerged cage at Andaman, feeder and Biomass estimation systems.

    Self sustainable profiling systems using Ocean thermal energy.

    Autonomous underwater vehicles that are propelled by altering buoyancy (ARGO floats/ gliders etc.) have been in demand in recent years as they have relatively high endurance. A float works on the principle of variable buoyancy. The buoyancy is varied by transferring oil between oil reservoir and an external bladder. These floats drift freely at a predetermined depth, then periodically ascend to the sea surface, profile the sea while ascending, report to a satellite and descend back to their targeted depth for the next mission. The lifetime of a float is limited by the capacity of the battery it can carry. The average life of a typical float is approximately 150 cycles: for a 10-day dive cycle, the average float can last about 3.7 years.

    In the current study, we propose improving the life cycle of a float/underwater vehicles using ocean vertical thermal gradient as an energy source. It is well understood that there is considerable temperature difference of about 10 to 15 degree Celsius between the warm sea surface (~25oC) and that at around 1000 m depth. As a float, descends and ascends, this temperature difference can be utilised to alter the buoyancy.

    Ocean thermal energy has not been extensively explored, mainly due to the inherent low energy conversion efficiency. Indeed, for a temperature variation between 1 and 20oC, the theoretical limit given by the Carnot cycle — which is much higher than the efficiency of practical thermo-mechanical and thermoelectric processes — is only 6.5%.

    Still, if harvested using small-scale, portable devices, ocean thermal energy can be used to power sensors and unmanned vehicles that are designed to conduct long-term missions within the environmental temperature differential. In this work, we investigate the use of solid/liquid phase-change materials (PCM) to develop scalable and efficient ocean thermal energy harvesters.

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    System Architecture of Thermal engine