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Water Quality Measurements Using a Novel Buoyancy Controlled Drifting Sensor Platform (BCDSP)
Start Date 06/01/2009
End Date 05/31/2011
Primary Partner: Clarkson University
Primary Contact: Ojo, Temitope - N/A
Other Project Contacts:
Bonner, Jim - Co-Principal Investigator
Janoyan, Kerop - Co-Principal Investigator
Project Type: CARTI IV
Technical Description:
Environmental protection relating to surface waters involves monitoring the health of ecosystems by sampling for constituents of interest either on a continuous basis or in response to episodic events. We propose to develop an inexpensive sensor-sensor platform for water quality monitoring by integrating sensors with a novel current measurement device derived from a six-degree-of freedom inertial navigation system (6-DOF INS). Density stratification in surface waters such as lakes, bays, and estuaries has been shown to contribute to the bio-geochemical cycling of material that aquatic life forms depend upon for growth and survival. For example, low levels of dissolved oxygen observed in certain water bodies, including the Great Lakes and Central New York regions, can be traced in part to density stratification. Understanding these biochemical cycling and transport processes requires long-term time-series measurements of important water quality parameters within the water column.
Synchrony of multi-parameter observations, which are traditionally derived from multiple instruments that have different sampling rates, has always been a challenge for scientists and water resource managers. Our objectives are to:
1. Integrate 6-DOF INS with a suite of sensors as a low-cost mobile sensor platform with vertical profiling capability.
2. Develop a buoyancy control system for the sensor-sensor platform.
3. Develop algorithms for instrument control, data analyses, post processing, and telemetry.
The BCDSP will profile the water column under buoyancy control and will be integrated with dissolved oxygen (DO), chlorophyll-a (chl ‘a') and chromophoric dissolved organic matter (CDOM) sensors to measure constituents of interest.
Expected Outcomes:
By integrating the sensors and sensor platform into one unit with on-the-fly data synchronization, we will be able to derive location and time-stamped concentration profiles within the water column in near real-time. The result will be a relatively inexpensive sensor/sensor platform with the capability to operate in relatively shallow waters.
Accomplishments:
Objective 1: Integrate an inertial navigation system (INS) with a suite of sensors as a low-cost mobile sensor platform with vertical profiling capability.
During the performance period, we finalized the conceptual and detailed design of main parts of the BcDSP which includes all structural, mechanical and electrical systems.
Structural Design: The structural elements were analyzed using finite element modeling (FEM) to determine optimum member profiles for the framing system.
Mechanical Design: The overall layout of the on-board sensors and navigation system has been completed. The system comprises five modules: INS module with GPS interface, a 3-channel fluorescence measurement module, a pressure-temperature measurement module, main microcontroller, power and data telemetry module.
Electrical Design: We finalized the general electrical schematics for the overall system. As part of the navigation system, a GPS unit was selected (Novatel OEMV-1, DGPS, SBAS 20 Hz) which is a commercial-off-the-shelf (COTS) unit.
Objective 2: Develop a buoyancy control system for the sensor-sensor platform.
Most of the effort during this period has been focused on Objectives 1 and 3 because Objective 2 requires design feedback from Objective 3 in terms of endurance, maximum submergence period and dive rate. The main work performed on Objective 2 during this period was the analyses of different platform configurations for the BcDSP that guided the final layout and framing design of the platform.
Objective 3: Develop algorithms for instrument control, data analyses, post processing and telemetry.
During this period, we began work on the position-velocity derivation based on output from the INS module. At this stage of the development, the majority of this work is being performed on the bench with simulated GPS data stream.
Benefits:
These technologies will provide a much clearer picture of characteristics within a water column through vertical profiling in near-real time.
For more information: tojo@clarkson.edu
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