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.. UHDAS+CODAS documentation master file, created by sphinx-quickstart on Wed Jan  7 14:24:39 2009.
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UHDAS-VMDAS comparison
--------------------------------------------

.. toctree::
   :maxdepth: 1


The figures below are from presentations about UHDAS and VmDAS.
This is a sparsely-annotated collection, comparing various aspects
of UHDAS to VmDAS.  A brief written explanation can be downloaded
:download:`here </images/introduction/UHDAS_VMDAS2.pdf>`.


Acquisition
^^^^^^^^^^^

At present, there is one company that makes science-quality vessel-mounted
ADCPs.

There are two acquisition systems for these systems:

 - VmDAS: provided by the manufacturer with purchase
 - UHDAS: developed at University of Hawaii


Data acquisition systems should provide three different functionalities:

(1) Required: satisfy basic requirements for logging data:

    - Control ADCP settings
    - Acquire ADCP data
    - Acquire ancillary data

         + position
         + attitude (heading)

    - timestamp all

(2) Desireable: Processing

(3) Desireable: Monitoring



-----

|
|


Core acquisition: Overview
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

UHDAS and VmDAS have different goals and software style:

|
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.. image:: uhdas-vmdas-acquisition-overview.png
   :alt: uhdas-vmdas-acquisition-overview
   :scale: 40

-------

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Core acquisition: Serial Setup
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


UHDAS is more configurable than VmDAS, making it
easier to collect the right messages and collect data
from enough feeds to provide some insurance against
unexpected failures.



|
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.. image:: uhdas-vmdas-acquisition-serial-setup.png
   :alt: uhdas-vmdas-acquisition-serial-setup
   :scale: 40

-------

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Core acquisition: Data Logging
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Many of the decisions made in the data logging architecture were
related to the operating system (linux vs/ windows) and
and styles of running programs on those operating systems.


|
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.. image:: uhdas-vmdas-acquisition-data-logging.png
   :alt: uhdas-vmdas-acquisition-data-logging
   :scale: 40

-------

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Processing
^^^^^^^^^^^^

Components:
~~~~~~~~~~~~~~~~~~~~~~~

If all has gone well up to this stage, there might not be much
difference in the potential final data quality from UHDAS or VmDAS,
but there are many ways in which UHDAS will yield a better final
dataset.  Most of that comes down to the single-ping editing done in
CODAs processing.


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.. image:: uhdas-vmdas-processing-comparison.png
   :alt: uhdas-vmdas-processing-comparison
   :scale: 40

-------

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Accessing Data Products
~~~~~~~~~~~~~~~~~~~~~~~~

Differences betwen UHDAS and VMDAS are related to the scope and
audience: UHDAS is meant to be a useful at-sea system for
ocean-going scientists; VmDAS is meant to be turn-key for a
variety of users.



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.. image:: uhdas-vmdas-accessing-data-products.png
   :alt: uhdas-vmdas-accessing-data-products
   :scale: 40

-------

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Monitoring
^^^^^^^^^^^^^

Much of what keeps UHDAS ADCP data quality high at sea is the
monitoring, which provides the opportunity for feedback to the
operator at sea that there is a problem, usually in under 24 hours.
VmDAS was never designed for that extra boutique level of
interaction.


|
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.. image:: uhdas-vmdas-monitoring.png
   :alt: uhdas-vmdas-monitoring
   :scale: 40