Introduction to Monitoring Dynamic 

Environmental Phenomena of the 

World Using Satellite Data Collection 

Systems, 1978 

Introduction to Monitoring Dynamic 

Environmental Phenomena of the 

World Using Satellite Data Collection 

Systems, 1978 

By William D. Carter and Richard W. Pau1son 

G EO LOG I CAL SURVEY Cl RCU LAR 803 

1979 
United States Department of the Interior 

CECIL D. ANDRUS, Secretary 

Geological Survey 

H. William Menard, Director 

First Printing 1979 

Second Printing 1979 

Library of Congress Cataloging in Publication Data 

Carter, William Douglas, 1926-

Introduction to monitoring dynamic environmental phenomena of the world using 

satellite data collection systems, 1978. 

(Geological Survey circular; 803) 

Bibliography: p. 

1. Astronautics in earth sciences. 2. Earth sciences-Remote sensing. I. 

Paulson, Richard W. II. Series: United States. Geological Survey. Circular 803. 

QE75.C5 no. 803 [QE33.2.R4] 557.3'08s [550' .28] 79-4220 

Free on application to Branch of Distribution, U.S. Geological Survey 

1200 South Eads Street, Arlington, VA 22202 
CONTENTS 

Page 

Abstract ----------------------------------------------------------------- 1 

Introduction ------------------------------------------------------------- 1 Data collection systems _ _ __ _ __ _ __ _ __ _ _ _ _ _ _ _ __ _ _ _ __ _ _ _ __ __ __ _ __ _ __ __ _ __ _ _ _ _ 1 

Data collection platforms _ __ _ __ _ __ _ _ _ ___ _ __ _ _ _ __ _ _ _ __ ___ _ _ _ _ __ _ __ ___ _ _ _ _ _ _ 8 

Data collection sensors _ __ _ _ _ _ __ _ _ __ _ __ _ __ __ _ _ ____ __ __ ___ __ __ __ _ _ __ _ __ _ ___ _ 10 

Sensor data -------------------------------------------------------------- 13 

General ------------------------------------------------------------------ 15 

Selected references ------------------------------------------------------- 17 Appendix A _ __ _ ___ _ _ __ _ _ _ __ __ _ _ _ __ _ __ _ __ _ _ ___ _ __ _ _ _ __ _ _ _ _____ _ __ __ _ _ __ _ _ 20 

Appendix B -------------------------------------------------------------- 21 

ILLUSTRATIONS 

Page 

FIGURE 1. Diagram of Landsat Data Collection System __ --------------------------------------- 4 

2. Sketch of geometric relationships of platform and receiving station in relation to polar orbiting satellite ___________ ---------------- ___ ------------------------------------ 4 

3. Sketch of Landsat and its components ------------------------------------------------- 5 

4. Landsat data collection platform _ _____ _ _ _ _ __ _ _ __ _ __ _ __ _ __ _ _ _ _ __ ___ _ _ __ __ _ _ __ _ _ __ _ __ __ 5 

5. Landsat ground stations--coverage areas --------------------------------------------- 6 

6. Sketch of synchronous meteorological satellite-GOES ---------------------------------- 7 

7. Planned global synchronous satellite operating positions ------------------------------- 7 

8. COM SAT /General data collection platform antenna ------------------------------------ 8 

9. Convertible Landsat/GOES data collection platform radio and t,est set ------------------- 9 

10. Landsat snow monitoring installation in Arizona -------------------------------------- 10 

11. Volcanologist carrying portable Landsat data collection platform to site in Cascade 

Mountains _ ____ __ __ __ __ __ ___ _ _ _ _ _ __ __ __ __ __ _ __ _ __ _ __ _ _ __ __ _ __ _ _ __ __ _ _ __ _ _ _ _ _ __ __ 11 

12. Volcanologist holding bore-hole tiltmeter prior to installation ---------------------------- 11 

13. ERTS/Landsat volcano monitoring network showing seismic e,vents of Volcan Fuego 

eruption, Guatemala ___ ------------------- _________________ ---------------------- 12 

14. Seismic event counter recorder, sensor, and Landsat DCP ------------------------------ 13 

15. Landsat water level monitoring platform, Everglades National Park, Florida ____________ :._ 13 

16. Surface water management model, Shark River Slough, Everglades National Park, Florida 14 

17. Landsat DCP on stream gaging station in Verde River area of Arizona------------------ 15 

18. Landsat reception station at Waltham, Massachusetts ---------------------------------- 15 

19. GOES data collection platform monitoring water level in Florida ----------------------- 16 

III 
Any use of trade names and trademarks in this publication is for descriptive purposes only and 

does not constitute endorsement by the U.S. Geological Survey. 
INTRODUCTION TO MONITORING DYNAMIC 

ENVIRONMENTAL PHENOMENA OF THE WORLD 

USING SATELLITE DATA COLLECTION SYSTEMS, 1978 

By William D·. Carte·r and Richard W. Paulson 

ABSTRACT 

The rapid development of satellite technology, especially in the area of radio transmission and imaging 

systems, makes it possible to monitor dynamic surface 

phenomena of the Earth in considerable detail. The 

monitoring systems that have been developed are compatible with standard monitoring systems such as snow, 

stream, and rain gages; wind, temperature and humidity measuring instruments; tiltmeters and seismic 

event counters. Supported by appropriate power, radios 

and antennae, remote stations can be left unattended 

for at least 1 year and consistently relay local information via polar orbiting or geostationary satellites. These 

data, in conjunction with timely Landsat images, can 

provide a basis for more accurate estimates on snowfall, water runoff, reservoir level changes, flooding, 

drought effects, and vegetation trends and may be of 

help in forecasting volcanic eruptions. These types of 

information are critical for resource inventory and 

development, especially in developing countries where 

remote regions are commonly difficult to access. 

This paper introduces the reader to the systems available, describes their features and limitations, and provides suggestions on how to employ them. An extensive 

bibliography is provided for those who wish more 

information. 

INTRODUCTION 

The growing world population and concomitant demands being placed on renewable and 

nonrenewable resources have required resource 

specialists to acquire and analyze current information about environmental systems on a 

regional, continental, or even global basis. Recent advances in electronics and space technology have demonstrated that much of the 

needed information can be acquired repetitively 

and cost effectively. This circular describes, as 

simply as possible, satellite telemetry systems 

1 

that can collect and transmit environmental 

data from remote regions of the world to regional resource information centers. We have 

prepared this circular in a narrative manner in 

an attempt to answer the most common questions asked about the systems. While we have 

not at~temp.ted to provide an exhaustive treatment, we hope that ( 1) this method will serve 

as a basic introduction to this technology for 

general use and (2) the serious investigator 

will use it as a springboard to directly contact 

the authors or other specialists listed in the 

references. 

Rainfall, snowfall, floods, hurricanes, volcanic eruptions and ashfalls, earthquakes, 

seismic sea waves (tsunami), and iceberg 

drifts are but a few of the active Earth processes that affect man's environment and his 

well-being. While satellites provide global imagery of many of these phenomena, there is 

a need for current in situ sensor data (i.e., 

data from environmental sensors on the Earth's 

surface). This current information is critical 

to the design of regional, national, or even 

global information systems that are timely and 

accurate to facilitate modeling and predicting 

for the future. 

DATA COLLECTION SYSTEMS 

What is a satellite Data Collection System? 

A satellite Data Collection System (DCS) is 

telemetric and uses an Earth-orbiting satellite 

to relay data from hundreds or thousands of 

widely distributed environmental sensors to 

one or more data receiving stations. There are 
three basic elements of any DCS. The first element is a field radio, usually called a Data Collection Platform (DCP), that is connected to 

environmental sensors such as precipitation or 

water-level recorders. The second element is a 

radio transponder (receiver/transmitter) on 

an Earth-orbiting satellite that is capable of 

receiving messages from a large number of 

DCP's. The third element is the data receiving 

station where data are retrieved from the 

satellites, processed, and disseminated to users. 

A satellite DCS can be configured in numerous 

ways that affect the cost, versatility, and ease 

of operation of the total system. 

How many satellite DCS's are in use or are planned? 

Three major U.S. Government satellite 

DCS's are presently available for use in North 

and South America, and a third commercialtype system was demonstrated in early 1978. 

The existing U.S. Government systems are 

aboard the Landsat, Nimbus F, and the Synchronous Meteorological Satellite/Geostationary Operational Environmental Satellite 

(SMS/GOES) series. The commercial-type system was jointly de·monstrated in late 1977 and 

early 1978 by the U.S. Geological Survey and 

the COM SAT General Corporation. In late 

1978, a joint United States-French Data Collection System will be available on the Tiros N 

satellite. 

What are the basic characteristics of satellite DCS's? 

Many characteristics of the DCS are governed by the satellite's orbit. If a satellite is 

placed in an orbit coincident with the Earth's 

equatorial plane at an altitude of about 36,000 

km, it is possible for the satellite's position to 

be constant relative to the surface of the Earth, 

i.e., the satellite orbits the Earth in 24 hours 

and appears to be motionless in the sky. Such 

orbits, :called geostationary or geosynchronous, 

provide a continuous opportunity to communicate through the satellite from positions on the 

Earth's surface that are in the satellite's field 

of view. Several DCS satellites are in geostationary orbit. 

Other DCS satellites generally are in nearpolar orbits and, at altitudes of approximately 

900 km, make one ·complete orbit of the E·arth 

every 100-110 minutes. The orbit periodically 

2 

carries the satelHte from the North Polar region down over U~e daylight side of the Earth 

to the South Polar region then up over the 

dark side of the Earth to the vicinity of the 

North Pole. When the next orbital transit is 

made, the Earth will have rotated on its axis 

about 25 o under the satellite's orbital plane; 

and the path of the satellite is displaced to the 

west (oi the previous orbit), cros1sing the 

Equator about 3,000 km to the west of the 

previous orbit. At higher latitudes the distance 

between orbital transits is smaller. The net result is that the satellite passes within radio 

range of all areas of the Earth several times 

each day. Ground platforms may be accessed 

by one of ·three poss;ible modes : ( 1) random 

access, (2) time-ordered acce:s~s, or (3) an interrogation mode. DCS's using the random 

access mode have one radio frequency channel, 

which means the time of a DCP's transmission 

is completely independent of the time of transmissions of other DCP's, and mutual interference from two or more DCP's is expected to 

occur at a random but predictable rate. In the 

event of mutual interference of the transmissions, no data are successfully relayed by the 

system. It is possible to predict the probability 

of successfully relaying data through a random-access system. The probability of successfully relaying a transmission through such a 

system is affected by the number of DCP's in 

the system, the radio frequency bandwidth, the 

data coding convention, the orbital characteristics of the satellite, and other system characteristics. The communications parameters 

and the mathematical models required to predict the performance of this type of system are 

well known to the communications engineering 

community. 

In summary, in a random-access system a 

brief data transmission, known as, a data burst, 

is emitted by each DCP once every several 

minutes continually round the clock, regardless 

of whether the satellite is within radio range. 

If the satellite is in a polar orbit, it will periodically pass within range of the DCP, receive 

one or more data bursts, and relay the data immediately to a receiving station if it is in range. 

For most locations in North A:merica, such 

satellites are within range !Of a DCP and a 

receiving station only about 2 to 3 percent of 
the 24-hour day. Some polar orbiting DCS systems use Doppler principles to track within a 

few kilometers the positions of DCP's on moving buoys and balloons from frequency shifts 

in the signal received by the satellite. Some 

provide data storage on the satellite to record 

data bursts from DCP's when a receive station 

is not in view. This capability enables collection of DCP data from any location worldwide. 

In contrast to the random-access DGS system is the time-ordered DGS, wherein a DCP 

is assigned a precisely defined time interval for · 

transmission. A ·precision timer .in the DCP is 

·set to initiate a transmission during a predetermined time interval ; for example, during a 

1-minute period once every 6 hours. If all 

DCP's in the system are well managed, no other 

DCP will transmit during that time on that 

channel, and communications can be established. The DCP precision timer, which generally is designed to be accurate to 1 part .in 

106 per y~ar, is designed to permit a drift of 

no more than approximately 30 seconds per year 

in the time of message initiation. Thus, if selftimed DCP's are assigned 1-minute reporting 

intervals and broadcast in the central :point of 

their time intervals, they should continue to 

operate without mutual interference for at 

le:ast 1 year. 

The last mode of operation used in DCS systems is the interrogate mode of operation, in 

which a DCP is commanded to transmit by a 

signal received from the data receiving station 

through the satellite. Under command from the 

receiving station, the satellite initiates a request for a DCP with the specified identification number (ID) to reply. Upon recognizing 

its ID, the DCP transmits its data. Under this 

mor!e of operation, the receiving station maintains control of the DCP's, causing them to 

adhere to the receiving station's schedule. In 

time of emergency, the ground receiving station 

can reschedule interrogations and attempt to 

initiate communications under a new schedule. 

What are the characteristics of the Landsat DCS? 

The Landsat DGS is a random-access system 

on a polar orbiting satellite. The U.S. Landsat · 

satellite, operated by the National Aeronautics 

and Space Administration (NASA), makes an 

orbit of the Earth every 103 minutes and can 

3 

receive data from up to 1000 DCP's in the instantaneous field of view (figs. 1, 2, 3, 4, and 5) . 

The Landsat Data Collection Platform 

(DCP) transmits 64 bits of sensor data plus 

station identification. This transmis,sion is at a 

rate of 5,000 bits per seeond, lasts 38 milliseconds, and is emitted from the DCP antenna 

approximately every 180 seconds. The antenna 

emits the radio transmission to a 140-degree 

cone abo~e the antenna plane at a radio frequency of 401.55 MHz. At any instant the satellite is capable of receiving data from Landsat 

DCP's tha,t are within radio range, which is 

approximately 2,000 km from the point on the 

Earth's surface below the satellite. If any DCP 

within range of the satellite transmits a mess .. 

age, it is instantaneously relayed to the receiving station if a receiving station is in range. 

DCS experiments in North America have 

shown that the typical DCP relays data through 

the Landsat sat,ellite during two and occasionally three orbits every 12 hours. 

Al,though the data collection syst1em has functioned well with Landsat 1 and 2, there is no 

current plan to continue this capability beyond 

Landsat 3. Preference is being placed on geostationary relay satellites such as GOES, except where position location is required. In 

view of the development of Landsat receiving 

stations around the world, the decision ·to drop 

the data relay capability will result in the loss 

of a flexibile DCS that is able to, relay data in 

areas of adverse topography. A reversal of this 

decision might be accomplished by exp~ressions 

of interest to NASA from the scientific community that wishes to employ the system. 

What are the characteristics of the Nimbus F DCS? 

The Nimbus F DCS is a random-access system on a polar orbiting satellite. The U.S. 

Nimbus satellite, operated by NASA, makes an 

orbit of the Earth approximately every 108 

minutes and can receive data from. up to 200 

DCP's in the instantaneous field of view. 

The Nimbus DCP transmits 32 bits of sensor 

data plus station identifi·cation. The trans.mission rate is at 100 bits per second, and a message is transmitted every 180 seconds. The 

omnidirectional antenna emits. a transmission 

at a frequency of 401.2 MHz. As in the Landsat syst,em, data will be relayed t1o the data re~ 
401 55 MHZ 

5 KBPS 

LANDSAT SPACECRAFT 

REMOTE SITE 

(ALASKA} 

REMOTE SITE 

(GOLDSTONE, CALIF.} 

2287. S. MHZ 

DCS ON 1.024 MHZ 

SUBCARRIER} 

TYPICAL REMOTE SITE (NETWORK TEST AND TRAINING 

FACILITY, GREENBELT, MARYLAND} 

1200-BIT NASCOM BLOCKS 

1200-BIT NASCOM BLOCKS 

NOTE: INDICATES EQUIPMENT 

~ WHICH IS UNIQUE TO 

~ DATA COLLECTION SYSTEM 

GODDARD SPACE FLIGHT CENTER 

(GREENBELT, MARYLAND} 

FIGURE 1.-Diagram of the Landsat Data Collection System. (Courtesy of General Electric.) 

FIGURE 2.-Sketch of geometric relationships of platform and receiving station in relation to polar orbiting satellite (Landsat). (Courtesy of General 

Electric.) 

ceiving station if there is mutual visibility of 

the DCP and data rec·eiving station fl'lom the 

satellite. In addition, it is possible for the satellite to record data from a DCP when the satel4 

li:te is out of range of a receiving station for 

later trans.miss:ion to the da.ta receiving station. 

This provides for global coverage not immediately possible on Landsat. 

In contrast to the Landsat system, the Nimbus F system provides for position location of 

the DCP's. There is a slight shift in the radio 

frequency of the DCP signal as the position of 

the DCP changes relative to the satellite as the 

satellite moves through its orbit. This so-called 

Doppler shift can be used to compute the DCP's 

location to within 3-5 km. The Nimbus system 

has been used numerous times to track drifting 

buoys in the ocean and balloons in the 

atmosphere. 

What are the characteristics of the GOES DCS? 

In contrast to the experimental polar orbiting random-access Landsat and Nimbus F 

DCS's, the SMS/GOES-DCS (fig. 6) is operational and is in a ~eostationary orbit. It uses 

in excess of 150 radio frequency channels for 

communication, as opposed to the single chan-
SOLAR 

ARRAY 

ORBIT ADJUST 

TANK 

DATA COLLECTION 

ANTENNA RETURN B~ 

VIDICON CAMERAS 

(3 ON LANDSAT 1 AND 2, 

2 ON LANDSAT-C) 

FIGURE 3.-Sketch of Landsat and its components. 

(Courtesy of General Electric.) 

nel employed by Landsat or Nimbus F. The 

SMS/GOES-DGS operates in a time-ordered 

or interrogate mode, employs two operational 

satellites, and uses a radio frequency of about 

402 MHz. 

The U.S. National Environmental Satellite 

Service operates two GOES satellites in position ~a:bove the Equator at 75° W. and 135° W. 

longitude with an in-orbit spare loca:bed at 105° 

W. The Soviet Union, Japan, and the European 

Space Agency (ESA) are scheduled to orbit 

three GOES-type satellites in the 1977-1978 

period to provide international and global 

Earth coverage (fig. 7). 

The GOES DCP transmits a variable length 

message at a rate of 100 bits per second. The 

length of the message varies depending upon 

the amount of data that is to be transmitted 

from the DCP. The message length can be as 

short as about 9 seconds when minimal data 

amounts are sent and as long as several minutes when thousands of bits of data are to be 

sent. Normally, the message length is on the 

5 

BATTERY OR DC 

POWER SOURCE 

(USER PROVIDED) 

FIGURE 4.-Landsat data collection platform. (Courtesy 

of General Electric.) 

order of 10-20 seconds long and contains several hundred bits of data. 

Each GOES satellite can accommodate a 

large number of DCP's. Depending upon how 

the system is managed, it is possible to operate 

10,000-20,000 DCP's through each U.S. GOES 

satellite. 

What are the characteristics of the Tiros N Data Collection 

System? 

The Data Collection System aboard the Tiros 

N satellite is a random-access system on a polar 

orbiting satellite and has many of the characteristics of the Nimbus F system. 

Each DCP transmits a data burst at a regular interval, every 40 to 200 seconds, depending on the ,type of platform. The DCP's can 

transmit messages at 401.65 MHz that contain 

DCP identification numbers and .from 32 to 

256 bits of sensor data. As in Nimbus F, the 

systen1 will have a global capability because of 

an onboard recording capability for storing 

data received from DCP's throughout the world 
120W 

····PLANNED 

---EXISTING FOREIGN 

-EXISTING U.S. 

sow 

.. ·· 

0 60E 120E 180E 

----------~---------+----------~------~--r----------r----------j--60S 

FIGURE 5.-Landsat ground stations-coverage areas. 

for later retrieval at data receiving stations at 

Wallops Island in Virginia and Gilmore Creek 

in Alaska. The data then are forwarded to 

Toulouse, France, for dissemination to users. 

As in Nimbus F, the DCS in Tiros N (which is 

also called Argos) has a position location capability and can locate a DCP to within 3 km. 

The system is a joint United States-French 

system that is operational and has a 1978-86 

service life. The French participant is Centre 

N ationale d'Etudes Spatiales ( CNES), and the 

United States participants are NASA and the 

National Environmental Satellite Service 

(NESS). 

What are the characteristics of the commercial Data 

Collection System demonstrated by the U.S. Geological 

Survey and COMSAT General? 

The·· COlVISAT General Corporation, Telesat 

of Canada, and the U.S. Geological Survey 

6 

demonstrated a satellite Data Collection System service (fig. 8) in late 1977 and early 1978 

using Anik, an existing Telesat of Canada geostationary ·Communication satellite. The commercial-type demonstration system used a small 

portion of one transponder on a commercial 

communication satellite, which normally has 12 

or 24 communications transponders, each of 

which can relay data from several hundred 

thousand DCP's. The other channels can continue to carry high volume commercial telecommunications traffic from and to major population centers. The demonstration verified that 

existing commercial satellites, operating at the 

4,000 and 6,000 MHz bands, can be used for environmental data collection and share the use 

of Anik on a noninterference basis with other 

commercial users. 
FIGURE 6.-Sketch of the synchronous meteorological 

satellite-GOES. 

The characteristics of the commercial-type 

DCS system include some of the characteristics 

of both the Landsat and SMS/ GOES systems. 

All of the DCP's on the commercial-type system 

were operated in random-access mode analogous to the Landsat. However, use is made of 

a geostationary satellite, which maintains 

mutual visibility for a large geographic area. 

The DCP's were programmed to transmit as 

frequently as every 15 minutes, although some 

operated at transmit intervals o.f 30 to 60 

minutes. The DCP's transmitted at a frequency 

between 5,925 and 6,425 MHz, and the duration 

of message transmission was 250 milliseconds. 

Each DCP message contained 64 bits of sensor 

data, although the expansion to a larger data 

message is possible. In the demonstration, 

which included the field testing of only 11 

DCP's in Virginia, Oregon, and Pennsylvania, 

and 2 DCP's in Canada, the probability of 

mutual interference is small and each DCP 

transmitted its message twice at its assigned 

time. In an operational system, each message 

would be transmitted two or more times to decrease the probability of unsuccessful relay of 

the data because of mutual interference. The 

DCP capacity of one transponder on a commercial communications satellite is forecast by 

COMSAT General to be approximately 300,000, 

depending on the temporal reporting schedule 

of the DCP's. 

FIGURE 7.-Planned global synchronous satellite operation positions. 

7 
FIGURE 8.-COMSAT/General data collection platform antenna. (Courtesy of COMSAT General.) 

DATA COLLECTION PLATFORMS 

What are the general characteristics of Data Collection 

Platforms? 

Generally, DCP's are small, occupying a 

volume of 20,000-50,000 cm3 and are designed 

to operate unattended in remote locations for 

long periods of time and operate from low 

power supplies, such as disposable batteries or 

solar charged batteries. They normally can interface with a variety of sensors that provide 

either digital or analog · input. Generally, a 

DCP is designed to operate with only one DGS, 

although DCP's can be bought that can operate 

with either the Landsat or the GOES-DCS. (A 

list of known DCP manufacturers in Canada, 

France, and the United States is. found in Appendix A.) Platforms often have rugged cases 

that shield their electrionics from weather although most, when fi,eld instaUed, are housed in 

a shelter of some sort. They normally can ope8 

rate in a -30° to + 50°C temperature range. A 

platform usually is connected only to sensors, a 

power supply, and an antenna. DCP manufacturers also may provide DCP test sets that are 

used to test the performance characteristics of 

the platform. 

What are the characteristics of Landsat DCP's? 

A Landsat DCP ,coMists of a self-timed radio 

transmitter and an antenna. It is normally connected to (1) a d.c. power supply that provides 

24 volts and (2) an interface between monitoring devices such as stream gages or seismic 

event counters that convert measurement information to digital information. The omnidirectional antenna of the Landsat DCP, aimed skyward, maximizes the possibility that the satellite will communicate with the DCP each time 

it passes within mutual view of the DCP and 

the Landsat receiving station. The 14-15 daily 
orbits of Landsat and range of radio telemetry 

system provide relay of data several times 

daily. The Landsat DCP's operate on a frequency of 401.55 MHz. The signals are currently received and relayed to Landsat reception stations only in the United States, Canada, 

and Chile. Other Landsat stations can receive 

such data but have not yet done so because the 

demand for such information has not yet 

developed. 

What is a Convertible Data Collection Platform ( CDCP) ? 

This is a platform that was developed for the 

USGS that is compatible with either the Landsat or GOES satellite system (fig. 9). It can 

operate as either a random-access DCP in the 

Landsat system or an ordered self-timed DCP 

in the GOES system. The mode of operation 

can be switched from Landsat to GOES by an 

electronics technician in a few minutes. It does 

use two distinct antennas, one omnidirectional 

for Landsat, and one directional for GOES. 

How does the CDCP operate? 

The CDCP collects, stores, encodes, and 

transmits environmental sensor data to either 

the Landsat or GOES satellites. It can accept 

serial-digital, analog, or parallel-digital input 

data, as well as a combination of the latter two. 

Up to eight analog inputs and (or) 64 bits of 

parallel digital input can be simultaneously interfaced with the CDCP. The 64 bits are 

sampled in 16-bit groups in sequence during a 

90-.second data acquisition cycle. 

The CDCP can store up to 832 bits of sensor 

data. N o·rmally data are acquired from sensors 

every 15, 30, or 60 minutes and are stored in 

the CDCP memory for later transmission. 

When operated in the GOES mode, the contents 

of the entire memory are transmitted thl'ough 

FIGURE 9.-Convertible Landsat/ GOES data collection platform radio and test set. 

(Courtesy of LaBarge, Inc.) 

9 
FIGURE 10.-Landsat snow monitoring installation in Arizona. Note omnidirectional antenna on shed (right) 

and snow pillow (left). (Courtesy of H. H. Schumann.) 

the satellite every several hours. When operated 

in the Landsat mode, 64 bits of the memory 

are transmitted with each message, and partitions of the CDCP memory are transmitted 

sequentially. 

Where can Platforms be installed? 

The platforms can be installed almost anywhere in a fixed geographic position or on 

moving buoys and balloons (figs. 10 and 11). 

Mountain tops, volcanoes, stream valleys, 

rivers, dam sites, lakes, seaports, and drilling 

platforms have been tested. There is no tracking capability on the Landsat or GOES satellites, as there is with Nimbus F and Tiros N, 

so drifting sea buoys or icebergs require communication through the latter two systems. 

How long will the Platforms work? 

With solar charged batteries, the DCP's can 

be left unattended indefinitely. Normally, sensors require cleaning, repairing, or calibrating 

10 

one or more times a year, and visits to remote 

sites for DCP repair should be few. Normal 

precautions should be taken to protect the DCP 

from weather extremes and vandalism. 

How much do the Platforms cost? 

The first Landsat DCP's cost approximately 

$2,500 each in the United States in 1972. The 

newer DCP's cost approximately $2,000-$3,500 

in the United States in 1977 for self-timed 

units, and $5,500 for interrogatable DCP's. 

Argos Beacon transmitters manufactured in 

France cost approximately $1,600. These prices 

do not include the cost of sensors or any increases that may occur due to inflation. 

DATA COLLECTION SENSORS 

What types of sensors can be attached to the Platforms? 

The platforms will accept data from almost 

any type of simple monitoring device that pro-
FIGURE 11.-Volcanologist carrying portable Landsat 

data collection platform to site in Cascade Mountains. 

(Courtesy of P. L. Ward.) 

vides a variable analog voltage output or two 

state digital output. Below is a list of devices 

that have been tested on DCP's (figs. 12, 13, 14, 

15, 16, 17, and 18): 

• Water-level gauges 

• Streamflow indicators 

• Water or air temperature 

• Air humidity 

• Water quality (pH, specific conductance, dissolved oxygen, and temperature) 

•· Snow Pillows (fig. 10) 

• Seismic event counters-at present it will 

not accept the more complex continuously 

recording seismograph data because the 

amount of information exceeds the transmission capacity (figs. 13 and 14) 

• Bore hole tiltmeters (fig. 12) 

• Wind speed and direction 

• Precipitation recorders 

11 

FIGURE 12.-Volcanologist holding bore-hole tilt meter 

prior to installation. Instrument interface on ground. 

(Courtesy of P. L. Ward.) 

How many sensors can be operated simultaneously? 

Up to 12 sensors usually can be operated 

simultaneously on DCP's. 

How much do the sensors cost? 

Most of the simple water monitoring sensors 

cost from $100 to $1,000 in the United States. 

The more complex devices may cost up to 

$10,000. A volcano monitoring Platform consisting of a multichannel seismic event counter 

and a tiltmeter costs about $6,400. 

Where can such sensors be obtained? 

A variety of companies around the world 

manufacture sensor devices that could be made 

compatible with the DCP's described herein. 

Our experience, however, has been limited to 

those available in the United States and 
ERTS IOIITORS 16 VOLCAIOES ... daily 

I 

I 

I 

to 311 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

FIGURE 13.-ERTS/Landsat Volcano Monitoring Network showing seismic events of Volcan Fuego eruption, 

Guatemala. (Courtesy of P. L. Ward.) 

12 
0 

,., 

-. 

• l i " l ~ I 

.. . ' ~ 

~!I~ Yit ['ll"T CQtN!(R f • p l..... u kw: •Ufl:!fik<A 

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d"M:l 

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FIGURE 14.-Seismic Event Counter recorder (right), sensor (left), and Landsat DCP (upper left). (Courtesy 

of P. L. Ward.) 

FIGURE 15.-Landsat water level monitoring platform, 

Everglades National Park, Florida. (Courtesy of 

A. Higer.) 

Canada. A sample listing is found in Appendix 

B. The authors would appreciate receiving information about other sources and other sensors that may be available. 

13 

SENSOR DATA 

Where are the satellite· relayed sensor data received? 

DCP data are currently received at NASA 

Landsat reception stations in the United States 

and Canada, and at the NASA/Chile Satellite 

Tracking and Data Acquisition Network 

(STADAN) station at Colinas, Chile. The 

GOES relayed data are collected at the NESS 

reception station in Wallops Island, Va. The 

U.S. Army Corps of Engineers operates a 

Landsat reception station in Waltham, Mass., 

(fig. 18) and a GOES reception station in 

Vicksburg, Miss. Eventually the Waltham station will become a GOES station similar to the 

one shown in figure 19. 
---.: .. -· -- ---------·-- -------- -:··-··- ---·---.: --

SHARK RIVER SLOUGH, EVERGLADES NATIONAL PARK 

ERTS·liiACES 

fOI •ASIIUIC CIABS II 

.TEl .. + 

ERTS DATA 

COLLECTION PLATFORM 

TO RELAY WATER LEVEL -- CURRENT 

VOLUME Of 

WATER IN 

STORACE 

NECESSARY DATA FOR WILDLIFE MANAGEMENT 

FIGURE 16.-Surface water management model, Shark. River Slough, Everglades National Park, Florida. 

(Courtesy of A. Higer.) 

How are the data transmitted to the user? 

Landsat DCS and Nimbus F /DCS data are 

available to users from the NASA Goddard 

Space Flight Center in Greenbelt, Md., and 

GOES/DCS data are availahle at the NESS 

Data Processing System in Suitland, Md. Tiros 

N (Argos) data will be available from CNES 

in Toulouse, France. Normally, it is the responsibility of the DCP operator to retrieve data 

from the reception or data processing systems 

that are maintained by the operator of the DCS 

system. For example, the U.S. Geological Survey has established automatic computer links 

with the NASA and NESS data processing facilities. DCS data are automatically entered 

several times each day into a USGS computer 

in Reston, Va., for processing and dissemination to USGS field offices. 

14 

How are the data processed? 

Because of the volume of information provided by the satellite DCS's, computers must 

be used to store and manipulate the data if a 

user operates more than a few DCP's. Normally the data must be converted to engineering 

units using sensor calibration data. 

How are the data converted to engineering units? 

The operator of a DCP must know the types 

of sensors that are interfaced with a DCP, as 

well as the order in which they are connected. 

He must also know how sensors electronically 

represent the physical condition they monitor. 

The sensor may output a voltage level to represent a physical condition. The DCP may represent the voltage by 8 to 16 bits of binary 

data, which are transmitted via the satellite. 
FIGURE 17.-Landsat DCP on stream gaging station in 

Verde River area of Arizona. (Courtesy of H. H. 

Schumann.) 

The data then must be converted back to represent the physical condition when processed 

at the user's data processing facility. 

GENERAL 

Are DCS's cost effective? 

The DCS's ar,e oost effective in general, but 

their cost effectiveness varies from country to 

country. In countries such as the United States 

where labor costs are high and increasing, it 

may be po,ssible to reduce the number of vis1its 

to field sit,es if DCP's can monitor the status of 

sensors. In developing countries where the number of trained scientis,ts and ,technicians, is 

limit ed and access is often difficult, DCS's can 

acquire useful data on a continuing basis from 

remote areas where S'everal major expeditions 

15 

FIGURE 18.-Landsat Reception Station at Waltham, 

Mass., U.S.A. (Courtesy of Army Corps of Engineers.) 

would be required :to obtain 1such data by field 

methods more than once. A potential user should 

evaluate the wor,th of the data and evaluate the 

co's't of alternative data eollection sehemes. An 

example of cost effectiveness of data coHection 

platforms was provided by the Salt River 

Water Users Association, which controls the 

distribution of irrigation water in the Phoenix, 

Ariz.,area. Better estimates of snowpack water 

content and projected runoff permitted the 

association to lower their water reserve behind 

dams in anticipation of spring floods. Not only 

did they avoid potential flood damage, which 

cannot be estimated, but they also produced 

$1,000,000 worth of additional electrical energy 

during the draw-off period (Schumann, 1975). 

What is the current extent of the use of CDCP's? 

Approximately 100-150 DCP's were tested 

under the Landsat 1 experiment in the United 

States and parts of Central America. The number of platforms in the operational SMS/ GOES 

systems increased to approximately 300 by 

early 1978. As of 1977, Canada had 23 DCP's 
FIGURE 19.-GOES data collection platform monitoring water level in Florida. (Courtesy of A. Higer.) 

installed and functioning and planned to install 

six more during the year (Halliday, 1977). 

Bolivia has two platforms, a Landsat DCP and 

a Landsat/ GOES CDCP, on loan from the U.S. 

Geological Survey, and purchased its first convertible platform in 1977 (Brockmann, pre.rs. 

commun.). Chile has three Landsat/ GOES 

CDCP's under a loan arrangement with the 

U.S. Geological Survey and is also operating 

eight procured by the Government of Chile 

(Araya, pers. commun.). Argentina has bought 

and operated four Landsat/ GOES CDCP's and 

may procure more. 

What is the projected forecast of DCP use? 

Feasibility studies are being conducted by 

the U.S. National Weather Service, Corps of 

Engineers, and the U.S. Geological Survey for 

s·everal thousand DCP's to be installed at 

water monitoring stations throughout the 

United States. A network of meterological stations is being used by the U.S. Bureau of Reclamation in its weather modification program. 

16 

The U.S. Bureau of Land Management is developing a system to monitor fire warning indices in vast forest areas of Alaska. Commercial satellite companies (for example, COMSAT 

General) are evaluating the possibility of providing a worldwide service for users of remote 

monitoring stations (fig. 19). 

Expressions of interest in ·becoming involved 

in DCP experiments have been made by Argentina, Brazil, and Peru. Workshops were conduc,ted to extend the technology to these countries during 1977. 

How can one keep abreast of DCS developments? 

In the United States an Interagency Working 

Group of the Federal Government publishes a 

bimonthly newsletter that monitors current 

events of DCS technology. To be included on 

the mailing list of the newsletter, one should 

contact Dr. Enrico P. Mercanti, Code 952, 

NASA Goddard Space Flight Center, Greenbelt, Maryland 20771. 
SELECTED REFERENCES 

Araya, F., Mauricio, 1976, Programa de Empleo de 

Sistemas de Coleccion de Datos por Satellite en 

Chile: Division NASA, Universidad do Chile, Santiago, May 1976, 68 p. 

---1978, Automatic collection of environmental 

ground data in ChHe by employing Earth orbiting 

satellites: International Symposium on Remote 

Sensing of Environment, 12th, Manila, Philippines, 

v. 3, p. 2131-2140. 

---1978, Main aspects on Chilean project to establish meteorological data collection system in the 

Antarctic by employing Earth orbiting satellites: 

National Science Foundation, Antarctic Treaty 

Meeting on Telecommunications, 3rd, Washington, 

D.C., Sept. 11-16, 1978, Doc. no. 7, 26 p. 

Bakor, H., Oscar, 1977, Manual para el ajuste y manejo 

de las plataformas de coleccion de datos via satellite ( CDCP) : Servicio Geologicio de Bolivia, Pro--

grama ERTS-Bolivia Informe, 49 p. 

Ball Brothers Re·search Corporation. 197 4, Convertible 

data collection platform manual: Boulder, Colo., 

July 18, 1974, 37 p. 

Barnes, J. C., Bowley, C. J., and Simmes, D. A., 1974, 

The application of ERTS imagery to mapping 

snow cover in the Western United States: Concord, Mass., Environment Research and Technology, Inc., Final Report unde·r Cont~act NA 55-

21803, 77 p. 

Bristol Aerospace Ltd., 1975, Data processing platform 

design specification: Winnipeg, Manitoba, Canada, 

Bristol Aerospace Ltd., Rocket and Space Div., 10 

p. 

Brockmann, C. E., 1977, Experiencia Bolivia sobre la 

utilization del sistema de colleccion de datos: 

Servicio Geologico de Bolivia, La Paz, Bolivia, Informe-Julio 1977, 20 p. 

Campbell, P. 1., 1975, Data processing platform design 

sp·ecification: Ottawa, Ontario, Canada, Inland 

Waters Directorate, De·pt. of Environment, 10 p. 

Cooper, Saul, and Ryan, P. T., eds., 1973, Data collection system Earth Resources Technology Satellite-!: 

Workshop, NASA Wallops Flight Center, May 

30-31, 1973, NASA SP-364. 

Delmas, G., 1975, Presentation du projet ARGOS: 

Centre Nationale d'etudes spatiales, le 31 mai, 

1975, Toulouse, France. 

Department of the Environment, 1971 Namakan Lake 

at Kettle Falls, radio system for transmission of 

water level data: Internal report dated November 

1971, Water Survey of Canada, Winnipeg, Manitoba, Canada. 

Eggert, D., 1970, Multipath study for a low altitude 

satellite utilizing a data relay satellite, system: 

Hughes Aircraft Company, NASA No. CR-143718. 

Endo, E. T., Ward, P. L., Harlow, D. H., Allen, R. V., 

and Eaton, E. P., 1974, A prototyp~ global volcano 

surveillance system monitoring seismic activity and 

tilt: Bulletin Volc-anologique, v. 38, no. 2, p. 315-

344. 

Fischer, W. A., 1978, Volcano surveillance program for 

the Pacific Oce-an areas and margins : Session of 

CCOP /Kuala Lumpor, 13th, Malaysia, Proc., Nov. 

22-Dec. 6, 1976. [In press.] 

Flanders, A. F., and Schiesl, J. W., 1975, Satelliteinterrogated data platforms in riv:er and flood forecasting: International Symposium on Remote 

Sensing of the Environment, lOth, Ann Arbor, 

Mich., Oct. 1975, Proc., p. 131-135. 

Fong, H., 1973, Hydrometerological automatic recording and telemetering system, Prototype HARTS-1 

(ERTS): Atmospheric Environment Service, Depart. of the Environment, Toronto, Ontario, 

Canada. 

Friedman, J. D., Frank, D., Preble, D. M. and Jakobsson, S. P., 1975, Thermal surveillance of active 

volcanoes using the Landsat-1 data collection system, 

prefaee and part 1: The Surtsey, Iceland temperature data relay experiment via Landsat-1: NASA 

no. CR-156971, NTIS E78-10121, 89 p. 

Friedman, J. D., and Frank, David, 1977a, Thermal 

surveillance of active volcanoes using the Landsat-! data collection system, par:t 3: Heat discharge 

from Mount St. Helens, Wash.: NASA no. CR156972, NTIS E78-10121, 35 p. 

---1977b, Thermal surveillance of active volcanoes 

using the Landsa~l data collection system, part 4: 

Lassen volcanic region: NASA no. CR-156973, 

NTIS E78-10123, 68 p. 

---1978, Thermal surveillanc·e of active volcanoes 

using the Landsat-1 data collection system, part 4: 

Lassen volcanic region: U.S. Geological Survey, 

Type III Final Report to NASA, 46 p. 

General Electric Co., Space Division, 1972, ERTS data 

users handbook: Beltsville, Maryland, prepared under NASA Contract NAS 5-11, 320 p. 

Halliday, R. A., 1975-a, Data retransmission by satellite 

for operational purposes: International Seminar on 

Modern Development·s in Hydrometry, Padova, 

Italy, Sept 8-13, 1975, Proc., UNESCO/IAHS, 

Paris, France. [In press.] 

---1975b, Use of satellites in data retransmission: 

WMO casebook on hydrological network design 

practice: World. Meteorological Organization, 15 p. 

---1977, Hydrologic data relay by satellite from remote areas: Technical and scientific sessions on 

water resources: w.oorld Water Conference (UNESCO), Mar del Plata, Argentina, March 14-25, 

1977, Proc., 21 p. 

Halliday, R. A., and Reid, I. A., 1975 Some operational 

uses of sat,ellite retransmission in Canada: International Symposium on Remote Sensing of the Environment, lOth, Ann Arbor, Mich., Oct. 1975, 

Proc., p. 1361-1366. 

---1977, Hydrologic applications of the TIROS-N/ 

ARGOS data collection syst.em: Argos Users Working Group Meeting, 1st Washington, D.C., April 

21-22, 1977: Ottawa, Ontario, Canada, Dept. of 

Fisheries and the Environment, Water Resources 

Branch. 

17 
Halliday, R. A., Reid, I. A., and Terroux, A. C. D., 

1976, Retransmission of hydrometric data in 

Canada: Ottawa, Dept. of Environment, R.eport to 

NASA no. CR-149651, 25 p. NTIS E-77-10116. 

Hig.er, A. L., Coker, A. E., and Cordes, E. H., 1973, 

Water-management models in Florida from ERTS1 data: Earth Resources Technology Sa.tellite-1 

Sympos.ium, 3rd, Washington, D.C., Dec. 10-14, 

1973, v. 1, sec. B, p. 1071-1088. 

Kahan, A. M., 1974, Use of the ERTS-1 satellite data 

collection system in monitoring weather conditions 

for control of cloud seeding operations: Denver, 

Colorado, U.S. Bureau of Reclamation, Type III 

Final Report to NASA, July 1974, 112 p. 

---1976, Use of the Landsat-2 data collection system 

in the Colorado river basin weather modification 

program: Denver, Colorado, U.S. Bureau of Reclamation, Type III Final Report to NASA, Feb. 

1976, 103 p. 

Krus, Jan., 1973, A water resource monitoring platform: Ottawa, Ontario, Canada, Dept. of the Environment, Type II Report to NASA for Period 

January to Aug., 1973. 

LaBarge, Inc., Electronics Division, 1975, Instruction 

manual for the convertible data cellection platform (CDCP) and related equipment: Tulsa, Okla. 

Ludwig, H., 1974, The NOAA Operational Environmental Satellite System-Status and Plans: American Meteorological Society, Conference on Aerospace and Aeronautical Meteorology, 6th, El Paso, 

Tex., Nov. 12-15, 1974. 

The Magnavox Company, 1974, Interrogated data collection Platform radio set, operation and mainte• 

nance manual: Fort Wayne, Ind., Jan. 15, 1974. 

Maitre, J., and others, 1974, Les sources d'energie 

autonomE'S dans les telecommunications: Commutation et Electronique, no. 44, janvier 1974, France, 

p. 85-96. 

Mathematica, Inc., 1974, The potential market for satellite data collection and localization services in the 

Unit,ed States: Princeton, N. J., Sept. 27, 1974, 94 

p. 

McKim, H. L., Cooper, Saul, Merry, C. J., and Anderson, D. M., 1975, Applications of remote sensing 

for Corps of Engineers programs in New England: 

International Symposium on Remote Sensing of the 

Environment, lOth, Ann Arbor, Mich., Oct. 1975, 

Proc., p. 189-190. 

Moody, D. W., and Preble, D. M., 1975, The potential 

impact of satellite data relay systems on the operation of hydrologic data programs: World Congress 

on Water Resources, New Delhi, India, Dec. Proc., 

12-17, 1975. [In press.] 

National Aeronautics and Space Administration, 1971, 

Earth Resources Technology Satellite data users 

handbook: Goddard Space Flight Center, Greenbelt, Md., Doc. no. 71 SD4249. 

Nelson, M. L., 1975, Da.ta collection system geostationary operational environmental satellite-preliminary report: National Oceanic and Atmospheric Administration, National Environmental Satellite 

Service, NOAA Technical memo NESS67, 48 p. 

18 

Paulson, R. W., 1973, An evaluation of the ERTS data 

collection system as a potential operational tool: 

Earth Resources Technology Satellite-1 Symposium, 3rd, Washington, D.C., Dec. 10-14, 1973, 

Proc., v. 1, s~c. B, p. 1099-1111. 

---1975, Use of earth satellite technology for telemetering hydrometeorological station data: International Seminar on Modern Developments in Hydrometry, Sept. 8-13, 1975, Padova, Italy, Proc., 

UNESCO/IAHS, Paris, France. [In press.] 

---1976, Use of Earth satellites for automation. of 

hydrologic data collection: Inte·rnational Seminar 

on Organizations and Operation of Hydrologic 

Services, Ottawa, Canada. July 15-16, 1976, Proc. 

Penick, David, 1975, The use of ERTS DCS in re1servoir management and op.eration: International 

Symposium on Remote Sensing of the EnvironmEnt, lOth, Ann Arbor, Mich., Oct. 1975, Proc. p. 

191. 

P.ersoons, E., and others, 1974, Telemeasurement in 

hydrology: International Water Resources Association, International S.eminar on Water Resources 

Instrumentation, Chicago, June 4-6, 1974, Proc., 

v. 1, p. 243-253. 

Preble, D. M., Friedman, J. D., and Frank D., 1976, 

Thermal surveillance of active volcanoes using the 

Landsat-1 data collection system, pt. 5: Electronic 

thermal ~sensor and data collection platform technology: NASA no. CR-156974, NTIS E78-10124, 

66 p. 

Pric·e, G. R., and Scheetz, V. R., 1977, Automatic environmental surface observation platforms (AESOP) for the high plains experiment (HIPLEX) : 

Bureau of Reclamation, Atmospheric and Water 

Resource Divis.ion, Contract no. 6-07-DR-20030, 

10 p. 

Rango, Albert, 1975, Operational applications of satellite snowcover observations project: International 

Symposium on Remote Sensing of the Environment, lOth, Ann Arbor, Mich., Oct. 1975, Proc., p. 

194-195. 

RCA Research Laboratories, 1975, Final report on a 

feasibility study of a data retransmis1sion platform: RCA Ltd., Ste Anne de Bellevue, Quebec, 

Canada, June 1973, 177 p. 

Robinove, C. J., 1969, Space technology in hydrologic 

applications: International Seminar for Hydrology 

Professors, 1st, Univ. of Illinois, Dept. of Civil 

Engineering, Urbana, Ill., July 13-15, 1969, v. 1, 

p. 88-107. 

Rattner, Donald, and Price, G. R., 1978, Testing of 

sateUite uplinked remote surface weather stations 

in the Sierra N e~vada: Ame·rican Mete·rological 

Society Conference on Sierra Nevada Meteorology, 

Lake Tahoe, California, June 19-21, 1978, Preprint, p. 19-22. 

Schumann, H. H., 1974, Hydrologic applications of 

ERTS-1 data coHection system in central Arizona: 

Earth Resources Technology Satellite Symposium, 

3rd, Washington, D.C., Dec. 10-14, 1973, Proc., v. 

1, sec. B., p. 1213-1223. 
Vannostrand, G. C., and Meyerson, G., 1973, Data collection platform/field test set program: Beltsville, 

Md., General Electric Co., NASA CR-133801, 

NTIS E 73-11008. 

Ward, P. L., 1974, A prototyp1e global volcano surveillance syst€m and Identification of a volcano-tectonic fault in Central America: Bulletin Volcanologique, v. 37, no. 3 p. 438-442. 

Ward, P. L., Endo, E. T., Harlow, D. H .. Allen, Rex, 

Marquez, Dan, and Eaton, J. P., 1974, Development and evaluation of a prototype global volcano 

19 

surveillance. system utilizing the ERTS-1 satellite 

data collection system: U.S. Geological Survey, 

open file rept., 154 p. See also NASA no. CR139222 and NTIS no. E74-10689. 

World Meteorological Organization, 197 4, Guide to hydrological practices: Geneva, Switzerland, WMO no. 

168, p. 4.5-4.9. 

---1975, Information of meteorological satellite programmes operated by members and organizations: 

Geneva, Switzerland, WMO no. 411. 
APPENDIX A-Representative Sources of Platform Information 1 

American Electronics Laboratories (AEL), P.O. Box 552, Lansdale, Pennsylvania 19446. 

Bristol Aerospace, P.O. Box 874, Winnipeg, Manitoba, R3C 2Z8, CANADA, (Landsat/GOES). 

COMSAT--General Corporation, 950 L'Enfant Plaza, S.W., Washington, D.C., 20024, USA 

(COMSAT). 

Electronique Marcel Das.sault, 55 Quai Carnot, 92214 St. Cloud, FRANCE, (Argos Beacons). 

LeBarge Incorporated, 6540 East Apache, Tulsa, Oklahoma 74115, USA (GOES/Landsat). 

MAGNA VOX Co., 2131 Coliseum Blvd., Fort Wayne, Indiana, 46804, USA (GOES/COMSA1.' 

General). 

Ball Bros. Research Corp., Boulder Industrial Park, Boulder, Colorado 80302 (Landsat/GOES). 

Handar Corp., 3327 Kifer Road, Santa Clara, California 95051 (GOES). 

The Sutron Corporation, 1925 N. Lynn St., Arlington, Virginia 22209. 

Metrix Systems Corporation, 736 North Beal St., Fort Walton Beach, Florida 32548, USA. 

Bendix Aerospace Corporation, 3621 South State Road, Ann Arbor, Michigan 48107, USA. 

1 This Ust is pmvided for information only. It is not considered complete nor does it imply or constitute an endorsement by the 

U.S. Geological Survey. 

20 
APPENDIX B-Representative Sources of Sensors Information 1 

CAE Aircraft, P.O. Box 1700, Winnipeg, Manitoba R3C 2Z8, CANADA, (Hydrologic senso·rs., 

e.g., water-level monitors). 

Electra-Physics Laboratories, Inc., Folsom, California 95630, USA, (Seismic event counters). 

Kinemetrics, Inc., San Gabriel, California 91778, USA, (Tiltmeters). 

Systron-Donnor Corporation, Inertial Division, Concord, California 94524, USA, (Seismic event 

counters). 

Bendix Aerospace Systems Division, 3621 South State Road, Ann Arbor, Michigan 48017, USA, 

(Seismic event counters) . 

Autonetics Division, Rockwell Corporation, P.O. Box 4192, 3320 Miraloma Ave., Anaheim, California 92803, USA, (bubble-level tiltmeter). 

General Eastern Corporation, 36 Maple Street, Watertown, Mass., 02172, USA, (relative humidity sensors). 

Hygrometrix, Inc., 285 5th Street, Oakland, California 94607, (relative humidity sensors). 

Phys-Chemical Research Corp., 36 East 20th St., New York, New York 10003, (Electro-humidity 

sensors). 

Thunder Scientific, 9720 Candelaria N.E., Suite C, Albuquerque, New Mexico, 87112 (Humidity 

sensors). 

Yellow Springs Instrument Company, Yellow Springs, Ohio 45387, (Evaporation rate and dewpoint, thermilinear thermistor network). 

Western .Scientific Services, Inc., Fort Collins, Colorado 80521, (ERTS Wind Averaging 

System). 

Belfort Instruments, 1600 South Quinten St., Baltimore, Maryland 21224, USA, (Remote Transmitting Precipitation Gage). 

Fischer-Por,ter, Warminster, Pennsylvania 18974, (Hydrostatic snow pillow, Water level recorder). 

Meteorology Research, Inc., P.O. Box 637, Altadena, California 91001 (Windvane, Windspeed 

anemometer) . 

1 This list is provided for information only. It is not considered complete nor does it i.mply or constitute an endorsement by the 

U.S. Geological Survey. 

1:! U.S. Government Printing Office: 1979-311-344/160 

21