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Патент USA US2407169

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Patented Sept. 3, ‘1946 t
‘ 2,407,169
1 UNITED ‘STATES PATENT 0 FFICE
2,407,169
'“
SYSTEM, FOR noca'rmo were»
SIGNAL narnscrons ‘
Arthur V. Loughren, Great Neck, N. 'Y., assignor,
by mesne assignments, to Hazeltine Research,
Inc., Chicago, 111., a corporation of Illinois
>
Application May 26, 1941, ‘Serial No‘. 395,172
9 Claims.
(Cl. 250-1) ‘
.
This invention relates to radiated-signal ‘re
?ectcr locating systems and, particularly, to such
systems of‘the type in which a predetemiined
,2
-
'
Also in accordance with a feature of the in
vention, the last-mentioned system may include
a reproducing device including an indicating
space is scanned with a sharply-concentrated. ‘
area corresponding to the predetermined space
radiated beam in order to locate a radiated-sig 5 scanned by the radiated beam, means responsive
rial de?ector,‘ such ‘asan aircraft.
to the received energy for producing an indi
It has been proposed in‘aircraft locating ‘sys
cationthereof of restricted area on the indicat
tems to scan a predetermined space in two di
ing area, and means for scanning the reproducing
' rections with a sharply-concentrated radiated
device in synchronism with the radiated scanning
beam of wave ‘signals and to receive thesignal 10 beam. By this arrangement, the position of the
which‘is reflected from the aircraft to provide
indication on the indicating area is dependent
an indication of its direction‘ from the locating
upon the direction of said radiated-signal re
station. It has also been proposed to de?ect the
?ector.
.
I
radiated beam at a different‘ frequency in each
Also in accordance with a feature of the in
‘of two directions in order to scan ‘a. given space 15 vention, a system for locating a radiated-signal
and to utilize a cathode-ray tube at the receiv
re?ector comprises, a radiating system having
ing ‘station as‘ the‘ direction-indicating device,
a radiation characteristic effectively in the form
the electron beam of the cathode-ray tube being ,
of a sharply-concentrated beam, means for ap
de?ected synchronously with the de?ection of the
plying a carrier signal to said radiating system,
radiated beam. However, such systems of the 20 and means for ‘scanning a predetermined space
prior arthave had the disadvantage that ‘me
with the, beam. This system also comprises
chanical beam-de?ecting arrangements were
means for receiving energy from the radiated
necessary for causing the radiated beam to scan‘
beam re?ected from the‘ re?ector and for utiliz
the desired space.‘ The general disadvantages
» ing the received energy to indicate the approxi
‘ of mechanical scanning. arrangements ‘are well 25 mate direction of the re?ector, and means for
understood by those skilled in the television art
compensating the indication for the time required
and many‘of these disadvantages are also pres
for the received energy to travel from said radiat
ent in mechanical scanning arrangements of the‘
ing "system to, .said means for receiving the
type under consideration.
radiated beam re?ected from the re?ector.
.It is an‘ object of the present invention, there 30 For a better understanding of the‘invention,
‘ , fore, to provide an improved system for deter
together with other and further objects there
mining the direction from a locating station of ‘a
of, reference is had to the following description
radiated-signal re?ector, such as an aircraft,
taken in connection with the accompanying
‘ It is still another object of‘ the invention ‘to
drawings and its scope will be pointed out in
provide an improved system for determining the 35 the appended claims.
direction of, and the distance to, a radiated
Fig. 1, of the drawings is a circuit diagram, signal re?ector, such as an aircraft, from‘ a lo
partly schematic, of a system for scanning a pre-_
'
‘
determined space with a sharply-concentrated
In accordance with a feature of the invention,
radiated beam of wave signals; Fig. 1a comprises
a system forlocating a radiated-signal re?ector '40 a set of graphs which are used in explaining a
comprises a radiating system having-a radiation
.portion of the operation of the arrangement of
‘ characteristic'e?ectively in the form of a sharply
Fig. 1; Fig. 2 is a circuit diagram, partly sche
concentrated beam, means for applying a carrier
matic, of a system embodying the beam-radiating '
signal to the radiating system, and means for
system‘ of Fig. 1 for locating a radiated-signal
vvarying ‘the frequency of the carrier signal to 45 re?ector, such as an aircraft; while Fig. 3 is a
scan a predetermined space in at least one direc
circuit diagram, partly schematic, of a modi?
tion with the beam. The system also includes
cation of the radiated-signal re?ector locating
means for receiving energy from the radiated . .system of Fig.2.
cating station.
- beam reflected from the re?ector and for utiliz~
Refen'ing‘now more particularly to Fig. 1 of
ing the received energy to indicate the direction‘ 50 the drawings, the system there represented is
of the re?ector, and means responsive jointly to
disclosed and claimed in a divisional application
i. the aforesaid frequency-modulated signal and
the re?ected signal for determining the distance
, of the radiated-signal ‘re?ector from the locat
ing system.
-
Serial No. 418,712, ?led Nov. 12, 1941. _ The sys~
tem comprises an antenna or radiating system
l0, means for applying a wave signal'to the an
55 tenna system for directive, radiation effectively
2,407,169
in the form of a sharply-concentrated beam, and
dimension at a second predetermined frequency.
there is provided a ?eld-frequency generator 15,
means for cylically varying the frequency of the
~ wave signal and, by virtue of the antenna char
also adapted to be synchronized by timer [4 and
having an output circuit coupled across a voltage
divider resistor 9, the mid-tap- of which is
acteristics as described hereinafter, causing the
beam to scan a predetermined space in one di
rection. The antenna system H] includes a plu—~
grounded. A control voltage is derived from one
rality of directional signal radiators shown as
end of resistor 9 and utilized to control phase
dipoles Dl-D24, inclusive, geometrically spaced in
shifter [20, While a voltage of opposite polarity
two dimensions and electrically spaced in one
is derived from the other end of resistor 9 and
dimension. Speci?cally, the conductors of the 10 utilized to control phase shifter l2d. Control
dipoles are all disposed in the same horizontal
voltages for phase shifters lZb and I20 are derived
plane and are parallel to each other. Dipoles
from intermediate points on resistor ‘9 as illus
D1—Ds, inclusive, are spaced in a ?rst‘dimension
trated in the drawings. The phase shifters
in a longitudinal array, while the sets of dipoles
I'm-12d, inclusive, may be of any conventional
Dz-Diz, inclusive, Dis-Dis, inclusive, and Die-D24. 15 type and it is to be understood that the phase
inclusive, are similarly spaced in other horizon
shift of each of these units is dependent upon
- tal arrays and are arranged, in the order named,
.. the magnitude and polarity of the control voltage
to one side of the set of dipoles D1-Da, inclusive,
derived from the resistor 9 for the particular unit
under consideration.
‘ to form an array of dipole sets, each set includ- ’ '
ing an array of six dipole antennae and the sets 20
In order to suppress radiation downward from
being spaced in a'second dimension. The dipoles
of each of the above-mentioned sets of dipoles
are energized in parallel except that the above
the plane including the conductors of dipoles
Dl-D24, inclusive, a re?ecting conductor [1 is dis
posed below each of the dipoles. These reflectors
mentioned electrical spacing in the one dimen
increase the useful energy in the desired direc
sion between the individual dipoles of the sets is 25 tion of radiation and minimize minor spurious
provided by delay networks F interposed be
tween adjacent dipoles. The geometrical spac
ing of the dipoles in each set in the above-men
beams.
'
In considering the operation of the system of
Fig. l and neglecting for the moment the func
tioned‘ one dimension is preferably made ap-'
tions of generators l3 and IE, it willvbe seen
proximately one-half wave length of the mean 30 that the system comprises a plurality of direc
or nominal frequency of the wave signal to be
tional signal radiators geometrically spaced in’
applied to the system, while the electrical spacing
the above-mentioned ?rst dimension and in the
due to delay networks F, F is made to be an in
above-mentioned second dimension and that the
tegral number of wave lengths at the nominal
signal radiators which are geometrically spaced
or mean frequency of. the system. The sets of 35 in the first dimension are also electrically spaced
dipoles are also preferably spaced in the dimen
by a time-phase displacement due to time-delay
sion normal to the sets, or in' the above-men
tioned second dimension, by a, distance approxi
matelyv equal to one-half the wave length of the
‘ units F. Considering for the moment only the
set .of dipoles Dl-DB, inclusive, in the condition
where they are all excited in the same phase,
mean or nominal frequency of the wave signal 40 it is seen that this is a known form of antenna
-to be applied to the system.
The means for applying a wave signal to the
antenna system In for directive radiation effec
tively in the form of a sharply-concentrated beam
array by which the radiation is concentrated rela
tive to the radiation pattern of a single dipole.
The concentration of energy into the beam takes
place at the expense of the regions generally in
comprises a high-frequency oscillator ll of any 45 the direction of the ends of the row of dipoles.
suitable type adapted for frequency modulation
Furthermore, it is seen that the re?ectors I 1 limit
individually coupled to each of the sets of dipoles
or suppress a substantial part of the radiation in
through transformers Ta, Tb, To, and Ta having
the direction in which they are spaced from their
their primary windings connected in series and
associated dipole conductors. The resulting
coupled to. the high-frequency oscillator II and 50 radiation pattern has a fan-shaped con?guration
their respective secondary windings coupled to
with its major dimension vertically above the row
the above-mentioned sets of dipoles through phase
shifters (21a, l2b, I20, and [2d, respectively, which
of dipoles, its smallest dimension parallel to the
row,.and its intermediate dimension parallel to
have the same phase shift at the nominal or mean
value of the ?eld-frequency generator. -
'
the individual dipoles.
65
,
_
I The effect of adding the other sets of dipoles is
In order to vary the relative phase of the sig
to concentrate the radiated signal to the form of
nals as applied to the signal radiators of antenna
a sharply-concentrated beam. In the case where
system In which are spaced in the above-men
all rows are excited with a common phase the
tioned one dimension at a U?rst predetermined
direction of this beamwill be at right angles to
frequency, there is provided means for varying in 60 the plane of the complete array. The reason for
a’ predetermined cyclic manner the frequency of
this is that the signals radiated from any pair of ,
the signal developed by the high-frequency os- ‘
antennae are in phase only in the direction
cillator II at‘the above-mentioned ?rst prede-'
normal to the plane containing the dipoles.
,termined frequency. Speci?cally, there is pro
Considering now the function of line-frequency
vided a line-frequency generator l3 which is 65 generator 13, it is seen that it is effective to
adapted to be synchronized from a timer H, the
vary the frequency of the output of oscillator ll
output circuit of the line-frequency generator l3
' cyclically and directly in accordance with its
being coupled to high-frequency generator II in
wave form, which is preferably a linear saw-tooth
order to vary the output frequency of this unit
wave form. Due to the fact that the dipoles of
in accordance with the wave form of the signal 70 each of the above-mentioned sets are electrically
developed by line—frequency generator IS, in any . spaced by the time-delay networks F, the effect
'
of this frequency variation is to vary the rela
In order to vary the relative phase of the signals
tive phase of the excitation of the dipoles of each
as applied to the signal radiators of antenna In
set. Thus, for a frequency somewhat different
which are spaced in the above-mentioned second .75 than the nominal or mean frequency of the sys
conventional manner.
5
2,407,189
' tern, the signals radiated by each of a pair of
, scanned by the beam which is radiated from. afi
adjacent dipoles of a set are not in phase in the
' vertical direction but are in phase in a direc
tion displaced therefrom byan amount dependent
-
upon the relative phase‘ of antenna excitation.
Thus, the line-frequency generator i3 comprises
means for varying the phase of the signal as ap
plied to‘ the signal radiators of each of the above
tenna system It. This reproducing ‘device com~
prises cathode-ray tube 24 of a conventional type
having a ?uorescent screen 25 which is the indi
cating area. The signal output of receiver 2|
is applied to the input circuit of cathode-ray tube
24 to provide an indication of a received signal
of ‘ restricted area on the indicating area 25.
mentioned sets at the frequency of the signal
Cathode-ray tube 24 is so biased by a source l9
generated by line-frequency generator l3 as a 10 that it is cut off in the absence of a received sig
result of the frequency‘ variation of the output
nal. Suitable operating potentials are provided
of oscillator‘ II by line-frequency generator l3
for cathode-ray ‘tube 24 in a manner well under
and for effecting spaceescanning by the concen
stood in the art. ‘ There are also provided means
trated radiated beam in lines in the above-men
for scanning the reproducing device 24 in syn
tioned one dimension.
‘
15 chronism with the radiated scanning beam from
If the effect of ?eld-frequency generator I5 . antenna system I0 sothat the position of an in
is now considered, it is seen that the voltageout
dicating spot on ?uorescent screen 25 is depend
put of this generator, which is also preferably of v ent upon the direction of the plane 20 from the
a linear saw-tooth wave form, is effective to vary
antenna system l0. ‘The scanning means com
the relative phase of the dipoles‘which are spaced 20 prises line-scanning plates 26, 21 and ?eld-scan
in the above-mentioned second dimension at the
ning plates 2&29 to‘which are applied, respec
frequency of this generator. Reference is made
tively, scann
to Fig. In for an-explanation of the operation of
this generator. Thus, curves I 1a, "b, He, and
_|‘|d represent the control voltages applied to phase
shifters |2a, i2b, He, and l2d, respectively. It
25
is thus seen that. at the beginning of the ?eld
. and that the signals applied to sets of dipoles
D13—Dll, inclusive,,and Die-D24, inclusive, are cor
respondingly shifted in phase in the opposite sense
:ge being applied to plate 21 through a resistor
The system of Fig. 2 also includes means re
sponsive to the frequency variation of oscillator
II for utilizing the received energy which is re
‘ trace period, ‘the signals applied to sets of dipoles
D1-Da, inclusive, and Dr-Du, inclusive are shifted
in phase in one‘sense and by different amounts
I voltages of the wave forms and
frequencies of the signals generated by generators
l3 and I5, respectively. the line-scanning volt
airplane 20 for selectively determin
39 ?ected'from
ing the distance of the airplane 20 from the locat
ing system. This means comprises a heterodyne
modulator "to one input circuit of which'is ap
‘ and by different ‘amounts. The result of this ex
plied a signal output of high-frequency generator
citation is to tilt the transmitted beam in the
|| through a limiter 34 and to another input cir
above-mentioned second dimension because it is 35 cult of which is applied a signal output from
only in such a direction that the signals radiated
receiver 2| through a limiter 38. The arrange
by two adjacent dipoles which are spaced in the
ment for indicating distance also comprises, cou
second dimension, for ‘ example, dipoles Da and
pled in cascade to the output circuit of modulator
Du, ‘are exactly in phase. ‘Furthermore, it is seen 40 32, a frequency-responsive network and detector
that the amount of this tilt in the second dimen
35, responsive to beat notes representing the dif
sion changes during the ?eld-scanning period due
ference frequency of the signal inputs to modu
to the change of ‘relative excitation phase of the
lator 32 and preferably having a linear charac
sets of dipoles effected by field-scanning generator ' teristlc over the range of beat-note frequencies
i5. Speci?cally, the amount of tilt in the second 45 encountered in operation, and a distance indi
dimension decreases to‘zero, at which time the
cator 38.
,
'
beam is vertical and then increases in the opposite
Due to the fact that more than one airplane
sense. ‘The arrangement of Fig. 1 is thus effective
may be in the space scanned by'the beam from
to vary, the direction of transmission of the
antenna system In at the same time, several in- _
‘ sharply-concentrated beam in two directions to 50 dications, as indicated by. the dots on ?uorescent
scan a predetermined space with the beam.
screen 25, may be produced simultaneously and
The system of Fig. 2 is one for locating a ra
the distance indicator 38 will, in general, indi
diated-signal re?ector, such as an airplane 2|),
cate a distance for each of these airplanes. In
and comprises a system for‘ scanning a predeter
order to provide means to facilitate the deter
mined space, including the airplane with a‘ 55 mination of which of the positions indicated on
‘sharply-concentratedbeam, such as .was ‘de
?uorescent screen 25 corresponds to a particular
scribed in detail in connection with Fig.1. Cir
‘ distance indication of distance indicator 2!, the
unit 38 is provided. The unit 38 comprises an
‘ cult elements of ‘Fig. 2 which correspond to those
of Fig. 1 have identical reference numerals.~ In
unlocking device for distance indicator 38 such
addition to the elements of the system of Fig. 1, 80 that, inthe absence of a signal input to the un
the locating system of Fig. 2 comprises means
lockingdevice, a distance indication is not de
for receiving energy from the beam radiated by
veloped by indicator 36. In order to energize
the antenna system l0 and reflected from the
the unit 38 in accordance with‘ any desired re
ceived direction indication on ?uorescent screen
' radiatedqsignal reflector ‘20. This means com
prises a ‘wave-signal receiver 2| having a sub
stantially nondirectional antenna system provided
by two dipole antennae 22, 23,. antenna 22 pref
65 25, there is provided a photocell 40, around which *
erably being parallel to the dipoles of antenna l0
and antenna "being at right anglesthereto to
there is a shield 4| having a relatively narrow
aperture 42. The output circuit of photocell 40
is connected in cascade through an ampli?er 43 v
and a differentiating circuit 44 to distance in
.‘ provide a response to re?ected waves having the 70 dicator 36.
polarization with‘which they were originally ra
diated or ‘a polarizationQO degrees displaced from
that radiated by antenna Ill. The system includes
a signal-reproducing device having an indicating
. area corresponding to, the predetermined space 75
Due to the fact that some time is required for
a transmitted signal to travel from the antenna
system Ill to the airplane 20 and back to the an
tenna system 22, 23, cathode-ray tube 24 tends
to become excited by receiver 2| with a time delay
2,407,169
1-
I
.
_
8
tance indication only for the particular signal a‘
which may be‘ sufficient, to’ give an inaccurate '
indication in ‘the line-scanning direction al
which is, at the moment supplying. energy'to pho- '
though ‘it will ordinarily be negligible in the rel
atively low-frequency ?eld-scanning operation;
toelectric cell 46.‘ The diiferentiating circuit 44
is provided so that the distance indicator is re
Therefore, in order to compensate, the direction
sponsive only to relatively rapid changes in the
indication on ?uorescent screen 25 for this time
signal input to photocell 40. Such a rapid
change in signal input to photocell. 40 will be .
developed each time the scanning beam of tube
vdelay, an output circuit of detector...“ is. coupled
across resistor 30.
I
>
.
Coming 'now to" the operationjofthe locating
.24 becomes incident upon the particular spot on r
system of Fig.2,‘ it will first be assumed that 10 the fluorescent screen 25 which is being utilized
to supply energy to photocell 46. , The ?uorescent
distance indicator 36 is not locked so that it is
material on the end of tube 24 will, in general,
continuously in a condition’. for operation and
have'a considerable time of luminescent decay
temporarily the functions of the unlocking device
which is disregarded by the differentiating cir
38 and the scanning compensating circuit includ
ing resistor 30 will be neglected. The operation 15 cuit 44.;
.
‘
,
.
'. ..
' Coming now to the arrangement of ‘Fig.2 for
of the beam-scanning arrangement including an
compensating the direction indications ‘on ?uo
tenna‘ system 10 being exactly the same as that
rescent screen'25 for the time required for'the
described in connection with the description of
the‘ operation of Fig. ~1,.a further description
radiated beam totravelfrom antenna ill to the
airplane 20 and backtoantenna system 22, 23, it
thereof is unnecessary herein.‘ [In considering
will be seen that each time the signal input to
the operation ofy-the remainder of the system of
Fig- 2 under the conditionsassumed, it will be
tube 24 causes the tube to be operated above its
above its cuto? point for received signals from .
correspond with the corresponding line-scanning >
cutoff point, the signal output from frequency
seen that the cathode-ray. beam of tube 24 is
detector 35 is also effective on the s'canningplates
caused to’scanthe. ?uorescent screen 25 syn-7
chronously with the‘ scanning of the predeter 25 26, 21 oi’tube 24. The circuit is so adjusted that.
the amplitude and polarity of this signal output is
mined‘sky space by the beam'radiated from an
effective momentarily to "back up” or retard the
>tenna7system l0‘. Since tube,v 24 is normally
line-scanning potential of tube 24‘to cause it to
biased beyond its cutoff point but is operated
receiver 2i, a spot indication .is provided on the 30 potential of generator l3 at the time the signal
being received left the antenna l0.~ The com
?uorescent screen 25 for each airplane in the ?eld '
pensating arrangement including resistor 30 may
scanned. Also, since the signal received by re’
ceiver- 2|, is delayed in time with reference to , be subject to an error. for airplanes'which are
near the line-scanning boundaries of ?uorescent
the signal output of. high-frequency oscillator I l
by the time interval. required ‘for the signal to 35 screen.25._ However, in practice, the antenna sys
travel from antenna [6 out to airplane 20 and
tem It! can be mounted upon a movable platform.
bach'to the-antenna 23', and since the frequency
so that, in general, the indication for any airplane
can be brought well within the indicating area
25. On the other hand, to prevent false indica
of oscillatorvli‘ has been altered during this time
by theiaction 9i’ line-frequency generator l3, the.
difference frequency. ofthese two signals is a
measure of the, distance. which the radiated beam
travelled between antenna l0, airplane 20, and
antenna system 22, .23. This difference fre
quency is,therefore, developed in the output cir
cuit of heterodyne modulator 32 and an indica
tions of the type just mentioned, a mask‘ can be -
disposed around the fluorescent screen‘ 25 to mask
the indication of any plane which may give such
a false reading.
~ .
'
>
‘
Y.
The arrangement of Fig.3 illustrates 'a modi- '
45 flcation of the system of Fig. 2 forindicating the
tion ‘of. distance is provided by means of the ac
tion- ofyfrequencyw-responsenetwork 35 which acts
component of direction corresponding to one of
the scanning dimensions of antenna vsystem ID
to convert the frequency‘value to an amplitude
for all received signals.
value, and distance indicator 36, which elements
Fig. 2 maybe included in the system of Fig. 3,
All of the portions of _ -
35 and 36 together may be simply a conventional .50 although for‘simplicity some of the portions of
Fig. 2 are not included, and elements which are
similar in the preceding ?gures have identical
form of frequency indicator. In the preferred
case, the frequency of the transmitted signal
varies at a uniform; rate with time and, there?v
forepany predetermined beat-frequency compo
reference numerals. The system of Fig. 3 com-, '
_ prises a cathode-ray tube-56 of conventional de-'
nent derived from modulator 32 represents the 55 sign having a ?uorescent screen 5| and having
its ‘input circuit coupled to the wave-signal re
same time delay-or distance regardless of the di
rection in which the signal from antenna I0 was
ceiver 2| in the same manner as was described
above‘inrconnection with the cathode-ray tube 24
radiated.
-
,
_
v
.
_.
‘
of Fig; 2. .However, one'set of scanning plates '
‘ Every airplane in the ?eld scanned by the beam
» radiated from antenna 10, therefore, is effective 60 54, 55 of cathode-ray tube 50 is-couple‘d' directly
across anoutput circuit of detector 35, while the
to provide a direction indication‘on fluorescent
other set of scanning plates 52, 53 is connected
screen 25 and a distance indication on distance
indicator 36.
It is for the purpose of determin- '
between the movable blade of a‘ single-pole,
-ing which direction indication correspondswith
" double-throw ‘switch 56 and ground. Line-scan
a particular distance indication that the unit 38 65 ning generator I3 is connected to one contact 51
is provided.’ Thus, in-considering the operation
oi'this portion of the system, it will be seen that,
of switch 56 through a'resistor 3ll’,'the function of
which is similar to that of resistor 30 of Fig. 2,
by moving aperture 42 across ?uorescentscreen
25, radiated energy from any of the direction-in
and?eld-scanning generator I5 ‘is connected to
the other contact 58.
"
In consideringthe operation of‘rthe'circuit of, >
_ dicating spots on fluorescent screen 25 maybe 70
‘caused to energize photoelectric cell 40. The sig
Fig. 3, it will?rstbe assumed that the blade of
nal output of the cell 40 is ampli?ed in amplifier
switch. 56 is operated to itsv upper contact 51 so '
43, differentiatedin diiferentiating circuit 44, and
utilized to overcome the normal cutoff bias on
that scanning plates 52,53 are energized by line—
The operation of ele
, scanning generator I3.
I, ‘distance indicator 36‘ so that it develops a dis 75 ments, the reference numerals of which corre
2,407,169
spond to those of .Fig. 2, is exactly as described
in connection with the description of the opera
tion of the arrangement of Fig. 2. Under the
While there‘ have been described what are at
present considered to be the preferred embodi
ments of this invention, it will be obvious to those
skilled in the art that various changes and modi
?cations may be made therein without depart
ing from the invention. and it is, therefore, aimed
in the appended claims to cover all such changes
conditionsassumed, when radiated energy is re
celved by receiver 2 I, the tube 50 is operated above
its cutoff point and, simultaneously, the cathode
ray beam is de?ected in one direction in accord»
ance with the distance of the airplane from which
the re?ected energy is received and is de?ected in
the other direction in synchronism with the line
scanning of the radiated beam. Therefore, a
trace is developed on ?uorescent screen 5|, con
sisting of a narrow upswing representing the air
10
and modi?cations as fall within the true spirit
and scope of the invention.
>What is claimed is:
1. A system for locating a radiated-signal re
?ector comprising, a radiating system having a
radiation characteristic effectively in the form of
plane. -The amplitude of such upswing, which
a sharply-concentrated beam, means for apply
may be measured from a horizontal indicating 15 ing a carrier signal to said radiating system,
means for'varyingthe’frequency of said carrier "
line on the end of the tube,'represents the dis
tance of the airplane, and its position laterally
signal to scan a predetermined space in at least
across the screen represents the corresponding
one direction with said beam, means for receiv
line-scanning co-ordinate. Similarly, the blade
ing energy from said radiated beam re?ected
‘of switch 56 may be closed in its lower contact 20 from said re?ector and for utilizing said received
58 and the corresponding ?eld-scanning co
energy to indicate the direction of said re?ector,
ordinate may be obtained. Thus, the modification
and means responsive jointly to said frequency
of the invention illustrated in Fig. 3 is e?ective
modulated signal and said re?ected signal for
to providean indication both of direction and of
determining the distance of said radiated-signal
distance for any airplane in the ?eld scanned by
re?ector from said locating system. '
~ the beam from antenna I0. If two airplanes are
2. A system for locating a radiated-signal re
present at a given time in this ?eld, indications
?ector comprising, a radiating system having a
will be received for each airplane. However, in
radiation characteristic e?'ectively in the form of
‘general, these airplanes will not be at the same
a sharply-concentrated beam, means for apply
distance and, for this reason, the line-scanning
ing a carrier signal to said radiating system,
and field-scanning co.-ordinates corresponding
means for varying the frequency of said carrier
to each airplane can be readily determined. ‘It
signal to scan a predetermined space in one
will be fully understood that the indicator tube
direction with said beam, means for receiving
50 of Fig. 3 can be used in conjunction with the
energy from said radiated beam re?ected from
indicator tube 24 of Fig. 2, and it will be seen
said re?ector and for utilizing said received
that the indications provided by screens 25 and 5|
energy to indicate the direction of said re?ector,
together are analogous to the three projections ‘ of a set of points in space.
means for heterodyning the transmitted signal
and said received re?ected signal to derive beat
While applicant does not intend to limit the.
notes dependent upon the frequency di?erence
invention to any particular design constants, the 40 therebetween, anda requency detector responsive
following values are appropriate for an airplane
to said beat notes for indicating the distance of
locating system:
said radiated-signal re?ector from said locating
7 system.
'
Mean or normal frequency
3. A system for locating a radiated-signal re
.for oscillator 11 _______ __ 100-1000 megacycles
?ector comprisirfg, a' radiating system having a
Frequency of line-scan,
radiation
characteristic e?ectively in the form
ning generator 13 ____ __ 500-5000 cycles
_of a sharply-concentrated beam, means for ap
Frequency ‘of ?eld-scan'
ninggenerator 15 _____ __ 10-30 cycles
‘rime'deiay of‘networks F- 5 to 10 periods at
r
1
,
'
4
normal carrier fre
quency
While a nondirectional antenna has been
illustrated in connection with receiver 2 I, it will
be appreciated that there are particular advan
tages to be gained in utilizing an antenna struc
‘ ture for the receiver which is similar to antenna
I 0._ If such an antenna is used it has the prop
plyinga carrier ‘signal to said radiating system,
means for scanning a predetermined space with
said beam, means for receiving energy from said
radiated beam re?ected from said re?ector and
for utilizing sa'id received energy to indicate the
approximate direction of said re?ector, and
1 means for compensating said indication for the
time required for said received energy to travel
from said radiating system to said means for re;
ceiving the radiated beam re?ected from said
re?ector.
_
w
»
erty of beinghighly directional for only the sig
4. A system for locating a radiated-signal re
nals received due to re?ection as described above. to ‘?ector comprising, a radiating system having a
The reason for this is that its directive proper
radiation characteristic effectively in the form of
ties vary with frequency in a manner analogous ,
a sharply-concentrated beam, means for ap
to that described above in connection with the
plying a carrier signal to said radiating system.
description ofthe operation of antenna 10. If
means for scanning a predetermined space with
‘ an antenna similar to that of antenna I0 is used 65 said-beam, means for receiving energy from said
at the receiver, it is necessary to provide phase
shifters corresponding to I2a-l2d, inclusive, of
‘Fig. 1, the corresponding phase shifters at the
radiatedv beam re?ected from said re?ector, a
reproducing device including an indicating area
corresponding to said predetermined space,
means responsive to said received energy for
receiver being controlled in exactly the same
manner that those at the transmitter are con 70 producing an indication thereof of restricted
.trolled. In such a receiving system, the receiver
area on said indicating area, means for scan
' proper is analogous to high-frequency oscillator
H and it is unnecessary to provide the counter
part of line-frequency generator 13. in the receiv
‘
ing system.
"
ning said reproducing device in synchronism with '
said radiated scanning beam, and means for
correcting said indication to compensate for the
distance travelled by the transmitted signal be
‘2407369
_\
,
i
v
"171
said’re?ector.,_
£5‘. a
“mio‘r
12
cyclic manner'ie?ectively-to vary the relative'phase
radiating: system land said-means‘ for
receiving energy from said radiated beamjwhere;
by, the o'sition of ‘ said ‘ indication‘- on"_ said indi
cating‘ areajii's' depe dent upon "the '_‘direction 01
tween , said:
or the si'gfnalsias applied to said vraldia'tors'which ,
are spaced msampne dimension at a'?rst prede
termined'frequency»,-means for varying the‘ rela
tive phase of said'signal as > a'pplie‘dto said ' signal
\ating'fa
'
radiatedfsignal re,
radiators :lwhi’ch' areispaced“ in ~ the ‘other dimen
si'clnlatav second predetermined» frequency ‘thereby
vtoilv'a'ry-"theidirection'fof transmission ‘of saidsra
ldiated
‘in two dimensions to‘ scan ai-prede
in two dimensions, a sourc'efof wa ' ‘signals-means
termin'ed' space: meansafor receiving 'energyafro'm
for eindividuallyvapplylng We, , ,_ ,snels'iirom’s?d "10.
'said'radiated beam re?ected irom’s'aid re?ector;-I'a
?écibrt‘ebmpriéine aredieiiiiesysiém‘mthidiilg 1a
plurality of Z s'ignal‘iradiators 'geemetriw11yjspacea
source‘ to‘ saidfsignaliradiators tor directive radia
tion effectively jin'the' iforrn ‘hi '8.“ sharplyéconcen
trated' beam; means‘ror 'e?ectivelyf varying the
reproducing device ‘ including an- indicating‘ area
corresponding to said predetermined space, means
fresponsivei to: said received energy; for‘ producing
7 ‘relative 'ph'aise‘of semi 818mb‘ warmed to-i'aid .
of a=restricted1 area on‘said
signal radiators which are spaced in one of said ~ - ',anindicationfthereof
indicatings‘area; meansliorlscanning'isaid repro
st‘
predetermined
irequencjy;
dimensions“ fat '
‘ducing'devicein synchronism with said‘f'radiated
e irélative'f'phas'e of-said- {sig
méaIiS for v5
'scanningi-‘beam;r-w‘hereby 'the'position of said. indi
signal radiators’ ‘which are
nalsieaapplie
. _.
rne'n‘sion at: a second pre
determined-frequency;‘merepyto'ivary the diree
aonb'rj 'tr'a'ris'missionpf "said radiated: beam two
spaced vin‘the othe
» cation‘- on said-‘indicating area is dependent upon
ii‘théfposltion or vsaid re?ectonand means. depend
a ‘ent
upon'the‘frequencyvariation of said carrier
"signal 'and'responsive tozthe frequency of said
dimensions‘ tqjsc'an'apredeterminedspace, 'means
v"received energy tori-indicating 1 the distance of
for receiving “energy ‘(ti-“om said vradiatedMani‘ Ire‘
?e‘c't'edi'from said'i-‘re?ectoni a'~reproducing"device
1 said re?ector " from"? ‘said *lo‘cating ' system; ~
‘i ll 8; Aysystem forfloca'ting'a' plurality of radiated
including an n'dicatirigi " area icorrespondi'ng 1 tov
saidf'predetermined; spacermeans'wesponsive to ,
“signal re?ectors comprising, a radiating system
j said received1 energy for producing? an ‘indication I ihaving’aradiationcharacteristicie?ectively in the
thereof of restricted'area'on saidindicatiri‘g- area, J w-formoot a'sharply-concentrated beam; means for
“applying a carrier signal tov saidradiating system,
and’ meansifonscanningsaidi reproducing device
insynchro'nism' with'saidi‘a‘diated scanning beam,~,
ienii'of, said'éindic'ation' one-said
whereby‘ lt'hei'p“ '
inuic‘atingvarea
30 means for ‘varying; the frequency of ; said carrier
' signal'toscan a predetermined-space in one direc
.; tion: with said beam,"v means ‘for. receiving ‘ energy
wiromis'aidfradiatedubeam reflected from said re
;v-?ectors and for: utilizing received energy “to indi
6. A system forlocatingalpluralityofjradiated
'- signal‘ "re?ectors comprising; a-raidiating “system? :35‘ cats witheldistance" and the component ,of ‘ direc
having = a radiation ‘characteristic? ‘effectively’ in
‘ ‘the f orni of- 'a' sharply-concentrated“beam; means
‘1 for applying a ‘ c'arrier‘j-‘signal~» to "fs'ai'd radiating
tion corresponding to ‘said scanningv direction for
s all of ‘said signal re?ectors;
;
.-
-
r
9. A system for locating a'pluralityoi radi
system; :‘means for varying-the frequency ot~"sa;id
,.;»a,tedi-signal re?ectors comprising-a radiating sys
~ carrier signal itol=scanrfa predetermined? space in’
1"
one direction with ‘said'beam‘, meanslfor’: receiving
energy froinfssaid radiated “beam re?ected from
said re?ectors and 'for utilizing said receiveden
ergy to indicates the directions'oi' » said- re?ectors.
andv means ' for selectively indicating :the distance i
of anyiof “said signal": re?ectors from‘ithe locating
systemp;
-
_
v,;
1
Yr
..:
..
7. Aisy'ste'mefor locating azradiated-signal re
?ector comprising‘, ~a=radiating system including
a plurality of signalv radiators geometrically spaced‘. ,
in two ‘‘ dimensions
:means 'for electrically
spacing :them ‘in one :' of the '‘ two dimensions; a
source of high-frequency wave signals, means for
individually applying wave. signals‘irom‘ said
source'to'v said signal radiators 'ior directive" radi-yv
ation eiiectively.inthe form of a sharply-concen
tern having a radiationcharacteristiceffectively
in \ ‘the : form-3 of 3a sharplygconcentrated, beam,
means for applying a carrier signal'tosaid radi
ating system, means for varying. the frequency of
said carrier, signal to scan>a"predetermined'space
‘in one direction with said beam, a cathode-ray
signal reproducing tube,'meansfor receiving en
ergy'from'said radiated beam re?ected from said
re?ectors and for, utilizing" received energy‘ to
control the beam ,of said'tube, means for de
riving from said received signalsand said fre
' quency-modulated carrier signal a signal indica
tive of distance'f'or each of said signal re?ectors,.
- ‘means for de?ecting the cathode-ray beam of said
1' tube in one. direction ,in accordance with said
last-mentioned signals,‘ and means for de?ecting
~ the cathode-ray beam of said tube in another
trated beamymeans comprising'said'i electrical
direction in synchronism, withsaid scanning‘ of
spacing means and means for varying the‘ fre
quency of‘ said-wave signals in a predetermined
said radiated beam.
i-
H
,
>
_
a
,
;
' _
ARTHURJV. LOUGHREN.
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