Airborne Data Acquisition Quality Control and Analysis System
Senior Project: 1994-1995
Marc Anderson, Alexandra Bokinsky, Kent Larson and Edward Stautler
NCAR operates four aircraft, ranging from a small glider to a C-130 cargo
plane. These aircraft are used around the world in support of NCAR's efforts.
The aircraft have a "home-built" data acquisition system and a network of Sun
workstations. All the instruments onboard are plugged directly into the data
acquisition system, which then samples the data, records it to tape, and then
passes the data off to data processing and real-time display software.
Instruments range from simple temperature and pressure sensors to particle
measuring, fast-response temperature, holographic cameras, inertial systems, UV
hygrometers, ozone and CO2 instruments, and wind measuring devices (vertical
and horizontal, speed and direction). There are typically 200 variables on a
given flight.
For various reasons during a flight, the data being gathered may not be valid.
In a simple case, an instrument may not be turned on, causing the recorded
samples to be some constant stream of meaningless data. Another example might
be a value going out of range periodically due to noise introduced into the
data stream. With such a large number of data variables being sampled, it can
be difficult to determine the validity of the data in real time. Due to the
cost of the flights, it is not cost-effective to wait to determine the data
validity after the flight is over, e.g. to discover that a particle-count
sensor reported all zero values because it was never turned on.
The goal of this project was to develop an airborne quality control and
analysis system. This system analyzes each variable for defects and alerts the
operator on board the aircraft of any suspicious conditions. There are two
parts to the project. The first is a library that performs the analysis for
given variable(s). The analysis includes detecting shifts, spikes, drift, range
checks, or whether the instrument is even on or working. The second part is an
X Windows/Motif graphical user interface which alerts the users onboard when
something has gone wrong with a given instrument or variable. The project was
developed in C++ to run on Sun hardware running Solaris 2.3 (UNIX SVR4).

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