An apparatus is described for monitoring the electric fields of cloud formations within a particular area. It utilizes capacitor plates that are alternately shielded from the clouds for generating an alternating signal corresponding to the intensity of the electric field of the clouds. A synchronizing signal is produced for controlling sampling of the alternating signal. Such samplings are fed through a filter and converted by an analogue to digital converter into digital form and subsequently fed to a transmitter for transmission to the control station for recording

Lovall, D. D.

Wojtasinski, R. J.

English

NASA Technical Reports Server

REPLY TO
ATTN OF: GP
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
WASHINGTON, D.C. 20546
JUL 3 1974
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TO: KSI/Scientific & Technical Information Division
Attn: Miss Winnie M. Morgan
FROM: GP/Office of Assistant General
Counsel for Patent Matters
SUBJECT: Announcement of NASA-Owned U.S. Patents in STAR
In accordance with the procedures agreed upon by Code GP
and Code KSI, the attached NASA-owned U.S. Patent is being
forwarded for abstracting and announcement in NASA STAR.
The following information is provided:
U.S. Patent No. :
^
Government or
Corporate Employee
Supplementary Corporate
Source (if applicable)
NASA Patent Case No.
NOTE - If this patent covers an invention made by a corporette
employee of a NASA Contractor, the following is applicable:
YES /—7
Pursuant to Section 305(a) of the National Aeronautics and
Space Act, the name of the Administrator of NASA appears on
the first page of the patent; however, the name of the actual
inventor (author) appears at the heading of column No. 1 of
the Specification, following the words "...with respect to
an invention of ..."
Bonnie L. Woerner
Enclosure
https://ntrs.nasa.gov/search.jsp?R=19740019749 2020-03-17T15:01:44+00:00Z
United States Patent
Wojtasinski et al.
tin 3,820,095
[45] June 25, 1974
[54] ELECTRIC HELD MEASURING AND
DISPLAY SYSTEM
[75] Inventors: Ronald J. Wojtasinski, Cocoa
'Beach; Donald D. Lovall,
Rockledge, both of Fla.
[73] Assignee: The United States of America as
represented by the Administrator of
the National Aeronautics and Space
Administration, Washington, D.C.
[22] Filed: Sept. 13, 1972
[21] Appl. No.: 288,847
[52] U.S. Cl 340/200, 73/170 R, 340/182,
340/151,324/72
[51] Int. Cl G08c 19/10
[58] Field of Search.: 340/200, 182, 184, 151;
73/170; 324/32, 72
[56] References Cited
UNITED STATES PATENTS
2,820,947 1/1958 Gunn 324/32
2,993,165 7/1961 Jauch 324/32
3,253,260 5/1966 Hawley 340/182
3,344,344 9/1967 Wales, Jr 324/72
Primary Examiner—Thomas B. Habecker
Attorney, Agent', or Firm—James O. Harrell; John R.
Manning
[57] ABSTRACT
An apparatus for monitoring the electric fields of
cloud formations within a' particular area which uti-
lizes capacitor plates that are alternately shielded from
the clouds for generating an alternating signal corre-
sponding to the intensity of the electric field of the
clouds. A synchronizing signal is produced for control-
ling sampling of the alternating signal. Such samplings
are fed through a filter and converted by an analogue
to digital converter into digital form and subsequently
fed to a transmitter for transmission to the control sta-
tion for recording.
4 Claims, 1 Drawing Figure
,36
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TRANSMITTER
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BUFFER
VIDEO
PRINTER
62
60
66
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3,820,095
1 2
ELECTRIC FIELD MEASURING AND DISPLAY Accordingly, it is an important object of the present
SYSTEM invention to provide an apparatus for monitoring elec-
tric fields of cloud formations over a particular area.
This invention described herein was made by em- Another important object of the present invention is
ployees of the United States Government, and may be 5 to provide a system which monitors the electric fields
manufactured and used by or for the Government for of cloud formations and prints the data collected onto
Governmental purposes without the payment of any a simulated map of the area being monitored,
royalties thereon or therefor. Still another important object of the present inven-
This invention relates to an apparatus for monitoring tion is to provide a system for monitoring the electric
electric fields, and more particularly to an apparatus 10 fields at various strategic locations within an area so as
for plotting the electric fields possessed by cloud for- to create a printed record or chart simulating the over-
mations over a given area. all electric field.
In recent years the space industry, in particular, has Other objects and advantages of this invention will
become extremely concerned with the hazards of elec- become more apparent from a reading of the following
trie fields generated by cloud formations in the area of 15 detailed description and appended claims taken in con-
missile launch sites. If the electric field intensity of a junction with the accompanying drawing wherein:
particular cloud formation is above a predetermined Tne FIGURE illustrates in block form an apparatus
value, there is a possibility that-a space vehicle being for monitoring the electric field of cloud formations
launched through the cloud may cause the cloud for- within a &™n area-
mation to discharge causing lightning to 'strike the 20 In order to record the electnc field of cloud forma-
space vehicle. This occured in the Apollo XII moon tions over a &ven ****il» necessary to strategically lo-
shot endangering the lives of the astronauts aboard the cate electric field measuring devices throughout the
space vehicle, as well as jeopardizing the function of a*ea to •* mapped and accumulating the readings from
many of the sensitive instruments carried thereon. If ,. these electnc field measuring devices and plotting such
the electric field of the cloud formations over a launch 25 on a simulated map of the area being monitored. In one
area is known, skilled technicians can anticipate to a Particular device constructed in accordance with the
certain degree the potential hazard of the cloud dis- Present m™Uo"' the/ield measuring dev'ces generally
charging. Therefore, by strategically locating a plural- tTA'^ l * ^ charactf. ">•'ncl"d« a
ity of electric field measuring devices geographically
 30
 sh
f
aft l?^ ?,?*£? ^  * If™ l^ *"%? T
throughout the area to be monitored it is possible to re- 3° J metallic leaf-like blades 16 earned on the top
cord fnd map the electric field of the cloud formations theref Positioned directly^low the blades 16 are a
.,
 K
, , . . . pair of capacitor plates 18. When the shaft 12 is rotated
over the area for subsequent study. the capacitor plates 18 alternate from a shielded to an
In accordance with the present invention ,t has been
 unsh Jded co^dition When the lates 18 are in the „„.
found that such can be accomplished ty providing an 35
 shielded condition ^ ^ th
K
e electric field of the
apparatus for monitoring the electrical fields of cloud
 douds direct, thereabove ^ signals received b the
formations over a predetermined area with the follow-
 itor la/es 18 m in tunij fed th h an H.
ing basic components: (1) A plurality of sensing sta- ^
 2Q wh£h ates an aiternating A.C. signal 22 on
tions positioned at predetermined locations within the
 its Qut ^ dtmaAiag A.c signal 22 is, in turn, fed
area being monitored, (2) each of the sensing stations 40
 into a sample and hold circuit 24.
including, at least a pair of capacitor plates located in
 Mso carried on the rotating shaft 12 are magnets 26
the area facing the cloud formation, means coupling
 which ^  provided for generating a synchronizing sig-
the capacitor plates to an amplifier, means alternately
 na] -Therc is one magnet 26 ^ blade for generating a
shielding the capacitor plates from the cloud formation p^
 each time a blade 16 passes over a capacitor plate
for generating an alternating signal on the output of an 45
 18 A magnetic pjc]c-Up 28 is provided closely adjacent
amplifier corresponding to the intensity of the electric
 tne magnets 26 for producing a pulse each time the
field of the cloud formations above the capacitor magnet is rotated thereby. These pulses are fed through
plates, means generating a synchronizing signal having amplifier 30 for amplification to generate the synchro-
a frequency corresponding to the rate that the capaci-
 njzing pulses 32 which are fed to the sample and hold
tor plates are alternately shielded, means activated by 50
 circuit 24. Such causes the sample and hold circuit to
the synchronizing signal for sampling the peaks of the sample the peaks of each of the half-cycles of the alter-
alternating signal for generating a D.C. signal which
 natjng A.C. signal 22. The sample and hold circuit 24,
varies according to the electric field sensed by the ca- in turn, produces an output signal which takes the form
pacitor plates, means for converting the varying D.C. of a varying D.C. signal. This varying D.C. signal is fed
signal to a digital signal, and a transmitter for transmit- " through filter circuit 34 which smoothes out the signal,
ting the digital signal responsive to receiving a com-
mand signal, a receiver located at the central command The output of the filter circuit 34 is, in turn, coupled
station, means for generating command signals for se- to an analogue to digital converter 36 which converts
lectively activating the transmitters at the sensing sta-
 6Q the analogue signals into a ten bit parallel signal. The
tions for transmitting the digital signals to the receiver, analog to digital converter may be any suitable conven-
and a computer provided for receiving the digital sig- tional analog to digital converter. One such converter
nals for feeding such to a map printer along with signals is manufactured by Burr-Brown Research Corporation
received from a digital map generator for superimpos- of Tucson, Arizona, and has a Model No. ADC 20-10-
ing the digital signals onto a simulated map of the area. „ N-BTC. The 10 bit parallel signal is fed in parallel form
Other recording devices such as video display equip- into any suitable conventional transmitter 38.
ment and printers which print data collected on the The transmitter has coupled thereto a control re-
electric fields in engineering units are utilized. ceiver 40 which generates a command signal for caus-
3,820,095
ing the transmitter 38 to transmit the digital signals pro-
vided therein. In order to activate the control receiver
40 a control transmitter 42, which may be located at
the master control station, is provided for generating a
600 cycle per second coded signal which provides a sig-
nal for the control receiver 40 to produce a command
signal. The command signal produced by the receiver
40 causes the transmitter 38 to transmit the 10 bits of
information coming therein out in serial form. Such are
at a carrier frequency of 1,600 hertz. For each sensing
station 10 there is a transmitter 38 which transmits a
signal representing the electric field directly above the
sensing station and a code identifying the particular sta-
tion from which the signal was generated. The signals
being transmitted from the transmitter 38 is received
by one of the receivers 44, 46, or 48. Each of the re-
ceivers, in one particular embodiment, is provided for
receiving information from twenty different transmit-
ters 38, therefore, when there are sixty sensing stations,
there will be three receivers such as shown in the draw-
ing.
The output of the receivers 44,46, and 48 include 10
bits of parallel information representing the electric
field sensed, ten bits of address information represent-
ing the particular sensing station and a data ready bit
which is fed to a digital scanner SO whenever there is
information received at one of the receivers 44,46 and
48.
The digital scanner, in turn, scans the information
being supplied from the three receivers and feeds such
information in parallel form into a computer 52 and a
parallel to serial converter 54. Connected to the output
the computer 52 is a buffer unit 56 which also has con-
nected thereto a conventional digital map generator
58. The digital information from the computer 52 and
the digital map generator 58 is fed through the buffer
56 to a map printing device 60 and a video display de-
vice 62. The map printing device prints a map of the
particular area being sampled showing the electrical
field values superimposed thereon. These electrical
fields normally show up in the form of circular fields
with the strongest point being in the center of the field.
From analyzing these maps a skilled person can gener-
ally predict when a lightning storm is about to occur.
The parallel to serial converter 54 converts the digi-
tal information into serial form and feeds such to a sec-
ond computer 64 which has a printer 66 coupled to its
output for printing the information in engineering
units.
While the particular circuit shown and described for
sensing electric fields, it is to be understood that it
could be used for monitoring many other functions,
such as temperature, pressure, and air pollutants. Such
may be accomplished by merely changing the type
sensing units utilized.
While a preferred embodiment of the invention has
been described using specific terms, such description is
for illustrative purposes only, and it is to be understood
that changes and variations may be made without de-
parting from the spirit or scope of the following claims.
We claim:
1. An apparatus for monitoring the electric fields for
cloud formations within a particular area comprising:
A. a pair of capacitor plates located in said area fac-
ing said cloud formation being monitored,
B. means for coupling said capacitor plates to an am-
plifier,
5 C. means for alternately shielding said capacitor
plates from said cloud formations for generating an
alternating signal on the output of said amplifier
corresponding to the intensity of said electric field
of said cloud formation above said capacitor plates,
10
D. means for generating a synchronizing signal hav-
ing a frequency corresponding to the rate said ca-
pacitor plates are alternately shielded,
E. means activated by said synchronizing signal for
15 sampling the peaks of said alternating signal for
generating a D.C. signal which varies according to
the electric field sensed by said capacitor plates,
and
F. means for converting said varying D.C. signal to a
20 digital signal representing the intensity of said elec-
tric field of said cloud formation.
2. The apparatus as set forth in claim 1 wherein said
means for alternately shielding said capacitor plates in-
cludes:
25 A. a vertical shaft,
B. a pair of blades carried on said shaft extending
outwardly beyond and above said capacitor plates,
and
C. means for rotating said shaft so that said blades al-
30 ternately shield said capacitor plates from said
cloud formation.
1
 3. The apparatus as set forth in claim 2, wherein said
means for generating a synchronizing signal includes:
A. a magnet carried on said shaft in alignment with
35 each of said blades, and
B. a magnetic pick-up means carried adjacent the
path of said magnets on said rotating shaft for gen-
erating a signal each time one of said magnets
passes thereby.
40 4. A system for charting the electric field for cloud
formations within a given area comprising:
A. a plurality of sensing stations positioned at prede-
termined locations within said areas,
B. each of said sensing stations including,
45 1. a pair of capacitor plates located in said area fac-
ing skywards,
2. means coupling said capacitor plates to an am-
plifier,
3. means alternately shielding said capacitor plates
50 from said cloud formations for generating an al-
ternating signal on the output of said amplifier
corresponding to the intensity of said electric
field of said cloud formation above said capacitor
plates,
55 4. means generating a synchronizing signal having
a frequency corresponding to the rate said capac-
itor plates are alternately shielded,
5. means activated by said synchronizing signal for
sampling the peaks of said alternating signal for
60 generating a D.C. signal which varies according
to the electric field sensed by said capacitor
plates, and
6. means for converting said varying D.C. signal to
a digital signal (and) representing the intensity of
65 said electric field of said cloud formation.


Electric field measuring and display system

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