The efforts of researchers at Mississippi State University to utilize space-age technology in the development of a self-contained, portable data acquisition system for use in marine and ecological research are presented. The compact, lightweight data acquisition system is capable of recording 14 variables in its present configuration and is suitable for use in either a boat, pickup truck, or light aircraft. This system will provide the acquisition of reliable data on the structure of the environment and the effect of man-made and natural activities on the observed phenomenon. Utilizing both self-contained analog recording and a telemetry transmitter for real-time digital readout and recording, the prototype system has undergone extensive testing

Johnson, R. A.

English

NASA Technical Reports Server

A DATA ACQUISITION SYSTEM (DAS) FOR MARINE AND 
ECOLOGICAL RESEARCH FROM AEROSPACE TECHNOLOGY 
Ab st ract 
By Richard A. Johnson 
Manager, MSU-MTF Research Center 
Mississippi State University 
This paper represents the efforts of researchers 
a t  lississippi State University to utilize space-age 
technology in the development of a self-contained, 
portable data acquisition system for use in marine 
and ecological research. The compact, lightweight 
data acquisition system is capable of recording 14 
variables in its present configuration and is suitable 
for  use in either a boat, pickup truck, o r  light air- 
craft. This system will provide the acquisition of 
reliable data on the structure of the environment and 
the effect of man-made and natural activities on the 
observed phenomenon. Utilizing both self-contained 
analog recording and a telemetry transmitter 
for  real-time digital readout and recording, the pro- 
totype system has undergone extensive testing at  the 
Mississippi Test Facility (MTF) . Currently under- 
going component performance upgrading, the proto- 
type system has been utilized in several environ- 
mental science investigations associated with a i r  
pollution investigations and weather modification. 
It is currently being used on the EcoSystem Research 
Project for marine data acquisition. 
Acknow I edg ment 
The author gratefully acknowledges the contri- 
butions of Dr. Lewis R. Brown, Dr. Richard E. 
Forbes, Dr. Michael R. Smith, G. S. Pabst, and 
M. L. Jones to the development of this prototype 
system and the preparation of this paper. This work 
was accomplished under NASA Grant NGL 25-001-028, 
NGL 25-001-032 and NGL 25-001-040. 
Introduction 
The recent emphasis on environmental science 
research in the U. S. has provided substantial 
impetus to research programs in the general 
area of marine ecologies. Researchers a re  develop- 
ing numerous prediction methods for use in the con- 
trol of air pollution; prediction of ecological alterations 
caused by pollutants in fresh water ,  estuaries, 
and the marine environment; detection of contami- 
nants in aquatic and terrestrial ecological systems; 
and related phenomena. Airborne remote sensing has 
opened up almost unlimited horizons for the collec- 
tion of resource data from aircraft and satellite plat- 
forms; however, at this stage of development the 
methods require sufficient amounts of accurate 
ground-truth measurements to substantiate the over- 
all base line. 
This paper presents the results of efforts by 
researchers a t  Mississippi State University to utilize 
space-age technology in the development of a self- 
contained data acquisition system for use in marine, 
ecological, and environmental research. The system 
was originally developed a t  the NASA/MTF with the 
aid of personnel provided by the MTF contractor, the 
General Electric Company. The basic system was 
developed with off-shelf components and excess 
aerospace assemblies and was initially designed 
to be mounted in a light, single-engine aircraft to 
provide economical operation for small investigations 
in atmospheric diffusion and weather modification. 
In addition, the data acquisition and data processing 
facilities of the NASA/MTF were utilized to the max- 
imum in providing real-time processing and graphical 
and tabular presentations of the experimental data. 
The data acquisition system is capable of han- 
dling 18 independent measurements in i ts  present con- 
figuration; however, onboard recording capability 
exists for only 14. The experimental data may be 
telemetered directly to the data handling center a t  
the NASA/MTF or may be recorded onboard as the 
individual situation requires. Most of the equipment 
utilized in the development of the data acquisition 
was performing service in another capacity prior to 
its utilization in the present system. 
System Development 
Criteria. The development of the original A i r -  
borne Data Acquisition System ( ADAS) resulted from 
149 
https://ntrs.nasa.gov/search.jsp?R=19730005115 2020-03-17T07:54:24+00:00Z
a direct requirement for experimental data to sup- 
port results predicted by a computerized numerical 
simulation program. In addition, it was desired to 
use the data acquisition and data processing facilities 
a t  MTF and at the same time provide a system which 
could operate independently of these facilities in the 
data acquisition phase of an investigation. These 
considerations led to the development of an ADAS with 
both onboard recording and telemetry capabilities. 
In addition, it was desired to develop a self-contained 
system which did not depend upon the aircraft power 
and flight systems. This feature provides for a more 
flexible system in that it can be installed in an air- 
craft with either 12-volt or  24-volt electrical sys- 
tems and also i t  is easier to satisfy Federal 
Aviation Regulations governing the installation of 
the ADAS in an aircraft. 
Hardware Description. Development of component 
hardware was initially divided into three main cate- 
gories: (1) equipment available directly usable or 
requiring only minor modifications, (2) equipment 
from outside procurements, ( 3) equipment requiring 
major modifications and/or new design. In order to 
satisfy the requirements delineated in the discussion 
on criteria, the main emphasis was on utilizing com- 
ponents which could be interfaced together with a 
minimum amount of design and fabrication require- 
ments. The telemetry equipment obtained was an 
excess, Saturn V ,  third-stage rocket unit. The 
seven-channel analog recorder, power supplies, sig- 
nal conditioners, resistance bridges, and the various 
sensing devices were procured separately. A l l  inter- 
face equipment, antenna hardware, sensor and 
transducer mounts, remote control and monitor panel, 
and the overall system configuration was designed 
especially for this application and fabricated at MTF. 
General Description of the  
Data Acquisition System 
The assembled DAS is set up for a bench checkout 
in Figure 1. In the upper foreground is the telemetry 
transmitter unit and mixer amplifier ( 1) ; in the lower 
foreground is the medium gain signal conditioner am- 
plifiers ( 2 )  ; and in the rear  is the analog seven-track 
recorder ( 3 )  ; the left panel mounts resistance bridges 
and calibration, control, and interface patching (4) ; 
the special power supplies a re  floor mounted to  the 
rear  of this assembly (5) : shown in the foreground is 
the remote power and control switches and the signal 
monitor display ( 6 )  mounted within close proximity 
to the operator, enabling the entire unit to  be con- 
trolled in the cab of the boat, truck, or  aircraft. The 
complete DAS is capable of being installed by two men 
in an 18-ft boat or  pickup truck, with sensors mounted 
in the water and calibration and ground check com- 
pleted within 1 hour. The overall dimension of the 
electronics package is 25 by 27 in. and 14 in. high. 
The total weight of the DAS, including all equipment 
and sensors, is slightly less than 250 lb. The dc 
batteries are mounted in spillproof canisters. 
Operational Mode 
Airborne Operations. Flight operations were 
conducted during 1970 at the NASA/MTF to test the 
operation of the DAS and the quality of telemetry data 
received and processed by the MTF Data Handling 
Center (DHC) . Numerous data runs were made at  
various times to flight check, calibrate and estab- 
lish operating characteristics of the individual meas- 
urements. Extensive data collection was performed 
on rocket exhaust plumes during the static firings of 
the Saturn V first- and second-stage booster rockets 
a t  MTF. Pre- and posttest calibrations were run 
between the aircraft and the DHC to establish relia- 
bility and accuracy of data acquired during static- 
firing measurements. 
Pr ior  to an airborne mission, the ADAS is bench 
checked and calibrated in the laboratory, and the 
calibrations and operational characteristics a re  
checked after installation of the ADAS in the aircraft. 
In most cases, i t  takes approximately I hour to 
warm up and ground check the unit. 
Marine Operations. From June 1971 until the 
present, utilization of this system has been devoted 
to ecological and marinc investigations. While this 
system can be utilized in a boat, truck, and aircraft, 
the initial phase has involved its use (mounted in a 
\. .-) in the EcoSyst  ;m Research Project area at  
7 ' 1  - ' ,  within the function of Mississippi State Univer- 
sity' s Environmental Science Laboratory at MTF. 
This laboratory is part of the MSU Research Center 
and is dedicated to the solution of pollution problems 
in the Central Gulf South area. The Eco-System Re- 
search Project is a ser ies  of ponds and artificial 
s t reams wherein simulated ecological-systems can 
be studied. In these ponds, special sensor packages 
will continually measure selected parameters, which 
are transferred to the instrumentation van via cables 
and connected to the data acquisition system for ana- 
log recording or  telemetry transmission to the DHC. 
Processing of Acquired Data 
Utilization of the MTF/DHC fo r  processing of the 
acquired data has proved to be significantly advantageous 
bath from the standpoint of accuracy of the results 
and the speed of data reduction. For  missions con- 
ducted within about 10 statute miles of the NASA/ 
MTF, the acquired data a r e  usually telemetered to 
the MTF/DHC for real-time processing and the ana- 
log recorder is used as a backup system. When 
missions a re  conducted farther away, they require 
the use of the analog recorder a s  the prime means 
of data acquisition, the analog tapes can be proc- 
essed a t  either the MTF/DHC or  other equivalent 
facilities. 
The MTF/DHC has the capability to receive, con- 
dition, and record the data from an FM telemetry 
system using an analog receiving station and a Sci- 
entific Data SDS-930 digital computer system, or 
to replay a prerecorded tape through a wideband 
recorder and into the cornpuler. 
The digital data a re  corrected using calibration 
tapes and other established methodology resulting 
in a digital Engineering Units tape ready for storage 
and later retrieval o r  to be stripped out a s  hard 
copy data . 
Application t o  the  DAS to  Environmental  
Science Investigations 
The DAS has been used to obtain data in several 
environmental science investigations. Included in 
these investigations have been probings of the ex- 
haust plume generated during the static firing of 
rocket engines, delineation of the structure of 
natural clouds under various meteorological condi- 
tions, quantitative contamination of aquatic and 
terrestrial ecological systems in support of studies 
directed toward predicting the ecological alterations 
caused by pollutants in fresh water, estuaries, and 
the marine environment. 
The accepted data gathering procedure, prior to 
the introduction of this system to marine and eco- 
logical research, is best illustrated by Figure 2. 
Manual measurements require a t  least one individual, 
sometimes two, for  each parameter measured, if 
they a r e  to be performed simultaneously. Compro- 
mises must be worked out a s  the amount of person- 
nel required to make 6-12 discrete measurements, 
a t  the same time, would be unrealistic for most proj- 
ects conducted in the field. The application then of 
this system to the problem of recording ecological 
data allows all parameters to be recorded simulta- 
neously and utilizes only two individuals to operate 
the system. 
The DAS was designed originally to acquire data 
related to  the growth and dissipation of rocket ex- 
haust plumes, which a r e  generated during the static 
firing of the S-IC and S-11 rocket engines. The ex- 
haust cloud, o r  plume, generated during the static 
firing has many characteristics which resemble a 
natural cloud. Considerable interest has been ex- 
hibited toward the possibility of using this isolated 
cloud as a well-defined model for weather modifica- 
tion research. These interests a r e  directed at  both 
the modification precipitation and electrostatic dis- 
charge in natural clouds and thunderstorms. In addi- 
tion, the exhaust cloud could cause an a i r  pollution 
problem in the event that toxic additives a re  used in 
the propellants. It was desired to  determine the 
diffusion characteristics of the exhaust plume of 
various rocket engines under various meteorological 
conditions. 
The investigations on the effect of various mete- 
orological conditions on the structure of natural 
clouds were conducted in approximately the same 
manner as for the rocket exhaust clouds. The pri- 
mary difference in the nature of the operations was 
that the natural cloud missions often extended over 
3- to 5-hour periods and over geographical locations 
up to 100-500 miles apart. In these cases i t  w a s  
desirable to recalibrate for each particular cloud 
probe, which would typically require 5-10 pene- 
trations. The handling of such volumious calibra- 
tions would be very difficult if  manually recovered, 
but is expeditiously processed by computer and 
significantly increases the reliability of the output. 
Research concerning the prediction of ecological 
alterations caused by pollutants in fresh water, es- 
tuar ies ,  and the marine environment and by the con- 
tamination of aquatic and terrestrial ecological 
systems is greatly facilitated by accurate and timely 
data collection in the field through the use of Field 
Monitoring Systems (Fig. 3) utilizing the DAS. This 
would allow collection of data from field locations 
for  subsequent use in simulating field conditions 
in the laboratory and pilot plant ecological systems. 
In addition, the immediate review and analysis of 
data acquired from the local environment would 
be available for use by local, State, and Federal 
planning functions for application to existing environ- 
mental problems. 
Conclusion 
The DAS discussed herein represents a unique 
application of aerospace technology and excess hard- 
ware to  problems in the environmental sciences. 
The development of the DAS has provided an econom- 
ical means of obtaining ecological, marine, and 
meteorological data using this portable system in a 
boat, truck, or  aircraft. 
The utilization of the data processing facilities 
a t  the NASA/MTF, in conjunction with the airborne 
data acquisition missions, has provided a real-time 
data processing capability which is extremely valu- 
able for basic research investigations and programs 
which involve the evaluation and development of 
sensors and sampling techniques. 
The availability and accessibility of Government 
excess equipment, with the unique innovations of 
application engineering and aerospace technology, 
provide the low-budget researcher a level of capa- 
bility never before attained. Since most university- 
sponsored research is through State or  Federal 
funding, this gain in capability and knowledge, and 
a t  the same time minimizing overall project cost, 
provides continuing benefits from the aerospace 
program long after the need of the original applica- 
tion has expired. Any enhancement to  the trans- 
ference of environmental science research into use- 
able application toward solving the pollution and the 
ecological problems facing the South Gulf area in 
particular, and the U. S. in general, will be an im- 
mediate benefit to us all. 
References 
1. Phase Coherent Frequency Synthesizer Techni- 
cal Manual. NRL Contract N-00014-69-c-0117, 
1970. 
2. Report of Department of Transportation A i r  
Traffic Control Advisory Committee. Alexan- 
der Report, 1969. 
8 
I 
Figure 1. Marine Data Acquisition System (DAS) . 
152 
Figure 2. Former data gathering procedure (manual method). 
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A Data Acquisition System (DAS) for marine and ecological research from aerospace technology

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