Graphics data conditioning program expedites engineering analysis of flight data and ensures timely correction of measurement errors. By adding interactive computer graphic displays to existing data conditioning programs, computational results are immediately visible, enabling on-line intervention and control of computer processing

Hagenau, K. H.

Mc Millen, G. C.

English

NASA Technical Reports Server

August 1968
	 .	 'Brief 68-10296 
NASA TECH BRIEF 
.	 -.	 ,.....	 -. 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Computer Graphics Data Conditioning 
A graphics data conditioning program has been de-
veloped as a computerized technique for rapid display, 
adjustment, and smoothing of flight data (obtained 
from tracking and telemetery instruments) to expedite 
engineering analysis and thus ensure timely correction 
of measurement errors. Conventional data condition-
ing programs operate in the batch-processing mode, 
with the attendant large quantity of keypunch cards, 
long turn-around time, and susceptibility to error. 
With these programs, results are often not visible for 
several days because of the number of operations and 
flow time required to obtain plots and listings of the 
conditioned data. The new technique, through the 
addition of interactive computer graphic displays to 
existing data conditioning programs, provides the en-
gineer with immediate visibility of computational re-
sults and permits on-line intervention and control of 
the computer processing. 
For the purpose of data conditioning, the errors of 
measurement are defined to consist of three com-
ponents: accidental error, systematic error, and noise 
error. Each of these components exhibits individual 
characteristics in the frequency domain and requires 
different methods of correction. 
The accidental error component is a sporadic, 
large-amplitude error such as would be caused by mal-
functions of the measuring system or large disturb-
ances external to the system. When the data are pre-
sented graphically, this error component is viewed as 
a "wild point" which is a significant distance away 
from the nominal trend of neighboring data points. 
The technique for correcting this error is detailed in 
the procedure. 
The noise error component consists of the higher 
frequencies (relative to the data frequencies) and is 
considered to have a zero mean. This error results in
the scattering of data points when they are viewed 
graphically. Two methods for the correction of this 
error are provided. 
The systematic error component has a form which 
is very similar to the data. Thus, specialized tech-
niques such as mathematical error models, calibration 
schemes, and least-squares adjustment of redundant 
measurements are required for correcting this type of 
error. A method of correcting a linearly time-varying 
bias is provided in a data-editing program. 
In addition to the correction of errors of measure-
ment, certain operations such as differentiation, inte-
gration, curve fitting, and selective frequency filtering 
may be accomplished to condition the data for engi-
neering analysis. Methods for performing these func-
tions are included. 
Notes: 
1. The technique for on-line graphical display and 
manipulation of data may be applicable in the 
fields of oceanography, meteorology, and trans-
portation. It may be extended to application in 
management information systems involving cost, 
schedule, and resources data. 
2. Complete details may be obtained from: 
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama 35812 
Reference: B68-10296 
Patent status: 
No patent action is contemplated by NASA. 
Source: G. C. McMillen and K. H. Hagenau 
of The Boeing Company 
under contract to 
Marshall Space Flight Center 
(MFS-14695) 
Category 06 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
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Computer graphics data conditioning

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