Electroluminescent (EL) remotely-controlled landing zone marker light system

A remotely-controlled lighting system for austere landing zone lighting includes a plurality of light units each having dual electroluminescent light panels, a plurality of remote controllers each having an electrical receiver, and a separate electrical transmitter. The light panel units and remote controllers, attached electrically, may also be attached physically and placed along the sides of a landing zone, while the separate transmitter is located at a remote, covert place, such as a foxhole. The transmitter and receivers of the remote controllers are capable of being preset to respectively transmit and receive a first sequence of coded pulses for turning "on" the light panel units and a second sequence of coded pulses different from the first sequence for turning "off" the light units. Also, the transmitter may be operated to repeatedly transmit one of the first or second sequence without transmitting the other sequence between the one sequence to ensure that all of the light units are either turned "on" or turned "off."

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention broadly relates to aircraft landing zone lighting 
and, more particularly, is concerned with an apparatus for illuminating 
and remotely operating the same. 
2. Description of the Prior Art 
The Air Force has requirements for a rapidly deployable, portable and 
remotely operable, austere aircraft landing zone marker light system. Such 
a system is needed to aid pilots in making successful night landings at 
unimproved austere landing sites for rapid deployment of troops or 
equipment. The ideal landing zone light system would use little power, be 
lightweight and portable, have sufficient visable range to be seen from 
several miles away, and be capable of reliable operation from a remote 
location. 
SUMMARY OF THE INVENTION 
The present invention relates to a landing zone marker light system which 
satisfies the aforementioned specifications. Particulary, the system uses 
electroluminescent (EL) lighting integrated with a remote control 
apparatus which provides personnel in charge of the landing zone with the 
capability to turn the light units of the system on or off in a reliable 
manner from a secure, remote location, such as a foxhole. This capability 
combined with the flat lighted area characteristics of the EL light units, 
being the preferred type of lighting, increases the survivability of the 
landing zone and landing aircraft by reducing the amount of time an enemy 
force has to acquire and target the landing zone and aircraft. 
Unique features of the present invention are the dual EL lamps used in each 
light unit and the ability of the remotely-controlled light apparatus to 
transmit and receive two separate codes, one for turning the light units 
"on" and the other for turning the light units "off." The dual EL lamps 
spaced approximately one inch apart in the light unit present a visual 
image to the aircraft crew member of an EL lamp several times larger than 
the two lamps or a brighter incandescent light source. This unique visual 
illusion allows the fabrication of a lighting system that minimizes size, 
weight and power consumption while maintaining the visible range of a 
larger, higher energy-consuming landing system. The separate on/off code 
feature of the remotely-controlled apparatus overcomes a major problem 
experienced with existing Air Force remote control lighting systems where 
only a single signal is used for alternately turning the lights on and 
off. If all of the lights do not turn on with the first transmission of 
the signal, the second transmission will cause some of the light units 
that are on to turn off. By utilizing a different coded pulse sequence for 
each function if all of the light units do not come on with the first 
transmission, second and subsequent transmissions will not turn the "on" 
lights "off" and vice versa. The remote control apparatus also has the 
capability to be preset to multiple sets of on/off codes to allow several 
lighting systems to be operated in the same area by one operator. 
Accordingly, the present invention is broadly directed to 
remotely-controlled lighting system, which includes: (a) a plurality of EL 
light units; (b) electrical signal receiving means being electrically 
connected to the light units; and (c) electrical signal transmitting means 
separate from the receiving means and light units. The transmitting means 
and receiving means are capable of being preset to respectively transmit 
and receive a first electrical signal for turning "on" the light units and 
a second electrical signal different from the first electrical signal for 
turning "off" the light units. More particularly, the receiving means is 
comprised by a plurality of remote controllers each being electrically 
connected, and in some embodiments of the lighting system physically 
attached, to one of the light units. Each of the first and second 
electrical signals is comprised of a different sequence of coded pulses.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now to the drawings, and more particularly to FIG. 1, there is 
shown several embodiments of a landing zone marker lighting system 
incorporating the features of the present invention. In each of the 
embodiments, the system is disposed for illuminating opposite sides of a 
landing zone 12 and for providing lead-in direction to the zone which may 
be located in an austere, possibly hostile, environment. The lighting 
system includes a plurality of EL light units 14 and a plurality of remote 
controllers 15 which each includes an electrical signal receiver 16 (FIG. 
4). The system further includes an electrical signal transmitter 18 and a 
strobe unit 19. 
Each light unit 14 is an EL light panel which will be described later in 
reference to FIG. 5. Each remote controller 15 is electrically connected 
and can be physically attached to one of the light units 14, or one remote 
controller 15 is electrically connected to the strobe unit 19. Thus, each 
light unit and/or remote controller combination and strobe are placed in 
such a manner to mark the landing zone 12. However, as seen in FIG. 1A, 
the transmitter 18 is physically separate from the light units 14 and 
remote controllers 15. It is located remote from the landing zone 
generally in a secure place, such as a foxhole. The transmitter 18, when 
operated by an operator stationed at the location of the transmitter, 
communicates with all of the remote controllers simultaneously. If 
desired, the remote controllers 15 with light units 14 and strobe 19 can 
be electrically connected directly to an external a.c. power source, as 
seen in FIG. 1B, or the light units 14 and strobe 19 can be electrically 
powered directly from an a.c. power source, as seen in FIG. 1C. 
In one important feature of the present invention, the transmitter 18 and 
receivers 16 are capable of being preset to respectively transmit and 
receive a first sequence of coded pulses P1, such as depicted in FIG. 3, 
for turning "on" the light units 14 and a second sequence of coded pulses 
P2, such as also depicted in FIG. 3, for turning "off" the light units. To 
ensure that all of the light units are turned "on" or "off", whichever 
condition is desired, the transmitter is operable to repeatably transmit 
the corresponding one of the first or second pulse sequence without 
transmitting the other sequence between the one. 
The transmitter 18, as seen in block diagram form in FIG. 2 and in detailed 
circuit form in FIG. 7, includes in a serially-connected arrangement a 
code generator 20, a modulator 22, an r.f. power amplifier 24 and an 
antenna 26. The transmitter 18 also includes an oscillator 28 connected to 
the amplifier 24. Further, a power switch 30 and code select switch 32 
(being shown only in FIG. 7) are provided which through coordinated 
actuation cause the transmitter 18 to transmit either the first sequence 
of coded pulses P1 or the second sequence of coded pulses P2. 
Specifically, the code generator 20 includes a code/decode module 33 and a 
module of preset dip switches 34 connected to some of the terminals of the 
module 33 such that when code select switch 32 connected to a terminal of 
the module 33 is in open condition, closing of power switch 30 causes the 
first sequence of coded pulses P1 to be generated by module 33 on output 
line 36. On the other hand, when code select switch 32 is in closed 
condition, closing of power switch 30 causes the second sequences of coded 
pulses P2 to be generated on output line 36. 
Each of the pulse sequences P1 and P2 are outputted on line 36 to modulator 
22. The modulator 22 is turned on and off in a sequence which corresponds 
to the coded pulses of respective sequence P1 or P2. As the modulator is 
turned on or off, the r.f. power amplifier 24 connected thereto by line 38 
is correspondingly turned on or off. Such operation of amplifier 24 causes 
a r.f. carrier signal sent to the amplifier 24 on line 40 from oscillator 
28 to be modulated into a pulsed format and transmitted from antenna 26 in 
a corresponding sequence. The antenna 26 is connected to the amplifier 24 
via line 42. 
The receiver 16, as seen in block diagram form in FIG. 4 and in detailed 
circuit form in FIG. 8, includes in a serially-connected arrangement an 
antenna 44, a super regenerative detector 46, an amplifier 48, a 
comparator 50 and a decoder 52. The antenna 44 receives the r.f. carrier 
signal modulated to the form of either the first or second sequence of 
coded pulses P1 or P2, depending upon which one is being transmitted, and 
outputs the same via line 54 to super regenerative detector 46. The latter 
outputs a signal on line 56 which has a waveform corresponding to the 
envelope of the input signal to the detector. This envelope signal is 
strengthened by amplifier 48 and then fed on line 58 to comparator 50. The 
comparator 50 senses the difference between the inputted signal and a 
fixed level d.c. voltage and outputs a pulse sequence which substantially 
replicates the respective one of the pulse sequences P1 or P2 being 
transmitted. The outputted pulse sequence is fed to decoder 52 via line 
59. Decoder 52 of the receiver 16 includes a code/decode module 60, a 
flip-flop 61 and a module of dip switches 62 which are preset identical to 
dip switches 34 of the transmitter's code generator 20. When the first 
sequence of pulses P1 on line 59 are inputted to decoder 52 its output on 
line 64 goes to a high state, while, on the other hand, when the second 
sequence of pulses P2 are inputted to decoder 52 its output on line 64 
switches to a low state. As will be seen shortly, when output line 64 of 
the receiver 16 is at a high state, light units 14 are turned on. In 
contrast, the light units 14 are turned off when the output of the 
receiver is in a low state. 
The manner in which the high and low states are produced on output line 64 
is as follows. Each time a negative-going clock pulse C is outputted on 
line 63 from module 60 and received at the CK input of the flip-flop 61, 
the Q output of the flip-flop connected to output line 64 changes states, 
going from either low to high, or high to low. Simultaneously, an input 
terminal (pin 11) of module 60, also connected to the Q output of the 
flip-flop 61 by line 65 correspondingly changes state. If such input 
terminal (pin 11) of module 60, for example, is at a high state, module 60 
will output a clock pulse on line 63 when the first sequence of pulses P1 
is received by the module 60 on line 59 at its input terminal (pin 16), 
but will not output a clock pulse on line 63 if the second sequence of 
pulses P2 is received. On the other hand, if input terminal (pin 11) of 
module 60 is at a low state, module 60 will output a clock pulse on line 
63 when the second sequence of pulses P2 is received by the module 60 on 
line 59 at its input terminal (pin 16), but will not output a clock pulse 
on line 63 if the first sequence of pulses P1 is received. In other words, 
once the decoder 52 has received one of an "on" signal (pulse sequence P1) 
or an "off" signal (pulse sequence P2), its output changes to a state 
which causes the light units 14 to be correspondingly turned "on" or 
"off". The decoder of each particular receiver 16 that reacted to the 
particular signal will not then react to the same signal again should the 
operator need to transmit it again in view that for some reason some of 
the receivers 16 failed to react to the initial transmission of the signal 
(i.e., their respective light units 14 failed to turn "on" or "off" as the 
case may be). Instead, the decoder 52 of each particular receiver 16 that 
reacted to the particular one signal P1 or P2 is now set to react to only 
the receipt of the other of the signals P1 or P2. 
Turning now to FIG. 5, there is shown an exemplary embodiment of one of the 
EL light units 14. In another important feature of the present invention, 
each light unit 14 includes a pair or dual light panels 66. Portions of 
one of the light panels 66 are broken away to expose its layered 
structure. The panel 66 includes a bottom conductor 68, which is usually 
aluminum foil, and a layer 70 which may be a mixture of Barium Titanate, a 
dielectric, a high dielectric binder and zinc sulfide phosphor or 
microencapsulated phosphors deposited on the bottom conductor. Next, a 
transparent conductor 72 usually of tin and indium oxide is applied. 
Finally, a layer 74 of Mylar.sup..TM. is applied and the entire assembly, 
only about one-thirty-second inch thick, is sealed or laminated in 
plastic. Two EL panels 66, for example, each 4 inches by 4 inches in size 
in an exemplary embodiment, are then enclosed in the light unit 14. Each 
panel 66 must have a capacitance of 0.05 microfarads or lower in the 
exemplary embodiment disclosed herein. The light unit can be mounted in 
either vertical or horizontal orientations. Also, a small EL light panel 
76 (FIG. 6) is mounted on the back of each light unit 14 and wired in 
parallel with the one panel 66 marked "EL #2" in FIG. 6. Its purpose is to 
provide a taxi-way marker for taxiing aircraft or to inform the operator 
who can be located behind the units 14, whether the light unit is turned 
"on". 
FIG. 6 illustrates the electrical components associated with each remote 
controller 15 for electrically connecting its respective receiver 16 
mounted therein to the two light panels 66 of the light unit 14. For 
powering the receiver and light panels, the remote controller has a d.c. 
battery 78 and a pair of d.c. power converters 80 mounted in the unit 14 
for converting the d.c. to a.c. power. For example, 15 volts of d.c. may 
be converted to 115 volts 400 Hz a.c. by using converters 80. The 
converters 80 are connected to output 64 of the receiver 16 through a 
relay transistor 82. The relay transistor 82 is turned on and off by 
corresponding high and low states on receiver output line 64. Each of the 
converters, also referred to as d.c. to a.c. inverters, is connected at 
its output by line 84 to one of the EL light panels 66 through a relay 86. 
In its position shown in FIG. 6, relay 86 connects lines 88 leading from 
the light panels 66 with output lines 84 from converters 80. When receiver 
output line 64 is at a high state and an on/off switch 90 is at its "on" 
position, the d.c. power source, battery 78, is used to activate the 
lights panels 66. When an auto/manual selection switch 92 is in a manual 
(closed circuit as seen in FIG. 6) mode, d.c. power is applied directly to 
the converters 80 through lines 94 and 96. This feature allows the light 
units 14 to be powered even if the receiver 16 or relay transistor 82 
fails. To protect the converters 80 in a no load condition a jumper line 
98 connects lines 94 and 96 in a plug 100. If plug 100 is removed from a 
receptacle 102 all power to the converters 80 will be interrupted. When it 
is desired to use strobe unit 19 in the light system, the strobe unit can 
be plugged into receptacle 102 in place of the plug 100 to obtain the 
power and remote control functions of the remote controller 15. The strobe 
unit 19 is, in turn, electrically connected to the light panels. 
As another important feature of the present invention, two pairs of on/off 
codes are incorporated by means of an A/B code selection switch 104. This 
feature can be used to add security to the system or to allow two systems 
to be operated in close proximity to each other. In view that the 
receivers and transmitter each utilize a 12-bit dip switch module, this 
feature (i.e., dual code selection) can be expanded in order to externally 
preselect more than two codes, if desired. As seen in FIG. 8, A/B switch 
104 is connected to one terminal (pin 10) of the receiver's code/decode 
module 60. The transmitter's code/decode module 33 also has an identical 
A/B switch 106. Both switches 104 and 106 must be in the same open (A) or 
closed (B) position in order for a set of pulse sequences P1 and P2 
transmitted and detected, respectively, by the transmitter 18 and 
receivers 16 to be the same. Thus, if the operator believes that an enemy 
knows a given set of first and second pulse sequences, such as when the 
switches 104 and 106 are in the A position, he may change the sequence 
pulse set by changing the switches from the A to B position. 
Alternately, as mentioned earlier in reference to FIGS. 1B and 1C, an 
external source of a.c. power may be used to power the light panels by 
connecting onto posts 108 and 110 on the remote controller 15 (see also 
FIG. 5), or by disconnecting the light panels 66 from the remote 
controller 15 and applying a.c. power directly to the light panels. Should 
one desire to use an a.c. power source to continuously power the light 
units and by-pass the remote operation feature of the present invention, 
it would merely be necessary to connect the source into the posts 108 and 
110. The relay 86 would then be actuated so as to connect a.c. lead lines 
112 with light panel input lines 88 while disconnecting converter output 
lines 84 from the same and disconnecting d.c. source 78 from providing 
power to receiver 16 and converters 80. In this mode all functions of 
remote controller 15 are by-passed. If a.c. power is interrupted, the 
remote controller relay 86 switches automatically back to d.c. power. 
It is thought that the aircraft landing zone marker system of the present 
invention and many of its attendant advantages will be understood from the 
foregoing description and it will be apparent that various changes may be 
made in the form, construction and arrangement of the parts thereof 
without departing from the spirit and scope of the invention or 
sacrificing all of its material advantages, the form hereinbefore 
described being merely a preferred or exemplary embodiment thereof.