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Description  |
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FIELD OF THE INVENTION
The present invention relates to data distribution, and more particularly
to a distribution system for securely distributing data within an aircraft
between an external source and an aircraft data system.
BACKGROUND OF THE INVENTION
In the daily preparation of military aircraft, it is often necessary to
store regularly updated security codes, known as crypto-variables or keys
into weapon control and other communication systems such as friend or foe
identification systems (IFF). This task is currently performed by a
portable code storage box which is connected to an aircraft code memory
device by means of conventional pin connectors. In the naval fleet this
transfer of security codes to an aircraft is done during pre-dawn hours in
all types of weather and sea conditions. On an aircraft carrier, this is
manually performed by a cryptocustodian to aircraft that rests on the
flight and hanger decks.
Although the procedure is generally satisfactory, it is a time-consuming
one requiring proper connector hook-up between aircraft and the
custodian's portable security code box. Due to the harsh environment,
connectors often deteriorate and the reliability of the connectors is
limited. Typically, such connectors are called upon to transfer digital
security codes to an internal code memory of the aircraft. When the
connectors between the portable code box and the aircraft evidence
physical or electrical deterioration, errors in code transfer are
possible.
In my co-pending patent application Ser. No. 224,605, a coupling device was
disclosed which preferably magnetically transfers data and circuit power
to an aircraft security code storage circuit without the inclusion of
mechanical pin connectors. In the environment of an aircraft, the
conventional custodian's security code portable transfer box is equipped
with a sending unit which is magnetically attached to the exterior of an
aircraft skin At an aligned position along the interior surface of the
skin is a receiving pick-up unit which magnetically picks up the digital
code and low voltage power being transferred by the sending unit. The
sending unit is easily removed after signal and power transfer have taken
place by simply detaching it from the aircraft. As will be appreciated,
such a simple and elegant technique avoids the problems of pin-type
connectors which have been employed heretofore.
In actual utilization of the coupler described, it is impossible to
completely eliminate electromagnetic radiation which might be detected by
a nearby intruder, such as an enemy submarine. Accordingly, it would be
highly desirable if the coupled data could be encrypted in a manner that
would avoid useful decoding of the coupled data.
In my co-pending patent application Ser. No. 258,349, a random number
generator, located within an aircraft, generates a random number which is
coupled to the sending unit of the coupler, and from there to a data
generator. This random number serves to encode the data which is
ultimately transmitted, as encrypted data, to the pick-up unit, via the
sending unit. Once the encrypted data is received by circuitry within the
aircraft, it is decoded in the same sequence as it was encoded during
encryption.
Accordingly, if the random number alone or the encoded encrypted data is
detected by enemy surveillance equipment, the true data itself cannot be
decoded since the decoding sequence is only properly performed by
compatible encoding and decoding equipment of the present invention.
Thus far, my co-pending applications have been described in terms of
providing secure data. However, it is possible for unfriendly parties to
employ available sensitive detection devices to detect radiated data
signals emanating from internal aircraft cables connecting the data memory
to the various data utilization devices within the aircraft Accordingly,
it is highly desirable to effect a method for masking the internal data
signals in such a manner that would prevent useful radiation detection.
BRIEF DESCRIPTION OF THE PRESENT INVENTION
Modern fighter aircraft have the data provided in various subsets for a
plurality of utilization devices on board the aircraft In prior art
systems, the various subsets are serially read into the various
utilization devices from a data storage memory. The primary concept of the
present invention is to provide the utilization devices with data subsets
which are loaded in parallel so that any radiated data of each subset is
masked by the other radiated superimposed subsets. More particularly, the
masking occurs because each of the parallel subset paths generates a
radiated signal which becomes superimposed with the other subset data
which produces a resultant scrambled signal which is extremely difficult
to process for retrieval of the individual data subsets.
BRIEF DESCRIPTION OF THE FIGURES
The above-mentioned objects and advantages of the present invention will be
more clearly understood when considered in conjunction with the
accompanying drawings, in which:
FIG. 1 is a diagrammatic illustration of the installation of a data coupler
on an aircraft skin;
FIG. 2 is a cut-away diagrammatic view of a magnetic induction sending and
pick-up pair, constituting a coupler, for which the present invention is
intended;
FIG. 3 is a diagrammatic elevational view of a section of an aircraft skin
to which a sending unit, such as shown in FIG. 2, is attached;
FIG. 4 is a block diagram of the random number system of my co-pending
application; and
FIG. 5 is a block diagram of the parallel data distribution system in
accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Prior to a discussion of the present parallel data distribution as depicted
in FIG. 5, a detailed description of the signal coupling system of my,
mentioned co-pending patent application Ser. No. 258,349 will be
discussed.
FIG. 1 is a diagrammatic view showing the coupler of my co-pending
application, shown installed on an aircraft skin. The portable code box
discussed in the Background of the Invention is indicated as an external
data/power generator 10 in FIG. 1. Such an external storing generator has
long been used in the prior art. In addition to being able to read out
stored data, the generator 10 is supplied with a switch (Power Inverter)
that initially powers an internal aircraft memory circuit when the
aircraft's own power is off, thereby enabling a memory to start its data
storage operation and send confirmation control signals back to the
generator 10. This is a great advantage as loading can take place at any
time prior to launch even without aircraft power or ground power on.
The coupling of power and data from the generator 10 includes a cable 13
connected at a first end to generator 10 and at an opposite end to a
sending unit 14. For example, such a unit may be an inductive primary unit
as shown in FIG. 2 and discussed hereinafter.
The sending unit 14 is equipped with a circular magnetic ring 24, which may
be of the gasket type used in home refrigerators. A mating magnetic ring
18 is appropriately cemented to the internal surface of an aircraft skin
16. The sending unit 14 is detachable from the aircraft skin by simply
exerting sufficient tension. Of course, other types of temporary
attachment may be employed such as suction, velcro, etc.
A complementary inductive pick-up unit 19 may be permanently cemented to
the interior surface of the aircraft skin 16 or it may be temporarily
mounted by utilizing ring magnets or the like, as just discussed in
connection with the sending unit 14. Signals sent from generator 10
through the sending unit 14 are inductively picked-up by the pick-up unit
19 and transferred to an internal data memory 12 by means of a cable 20.
In operation of the device illustrated in FIG. 1, power may be supplied
from the external data/power generator 10 to the internal data memory 12
in order to power the memory circuits if the aircraft power supply is
turned off. The data memory circuits 12 are of the type that already exist
aboard military aircraft After the memory circuits have been sufficiently
energized, the generator 10 may be switched to a data transmission mode so
that the sending unit and pick-up units 14 and 19, respectively, may
couple the data to the data memory 12.
The particular structure of the inductive coupling units 14 and 19 are
illustrated in greater detail in FIG. 2. However, it is to be emphasized
that other types of sending and pick-up units, other than the particular
inductive units illustrated in FIG. 2, may be employed. For example, other
types of magnetic, capacitive, sonic or vibratory transducers are
technically feasible
The particular magnetic inductance units shown in FIG. 2 include a sending
unit 14 having a ferromagnetic housing 22 with a ring magnet, preferably a
rubber gasket type ring magnet 24 cemented around the bottom periphery
thereof. The magnet is for detachable connection to the aircraft skin by
means of the magnets internally cemented thereto, as previously mentioned
A cylindrical ferromagnetic coil form is axially disposed within the
housing 22 and serves as a core for windings 28 also located within the
housing The winding 28 serves as a primary winding and cooperates with a
secondary winding, located within the pick-up unit 19, as will be
discussed hereinafter. An electromagnetic field is created between the
primary winding 28, core 26 and the housing 22.
The pick-up unit 19 includes a similar structure, namely, a central
ferromagnetic core 32 with a secondary winding 38 secured thereto and a
ferromagnetic housing 30 which may be opened on the illustrated top end 34
to allow the sending structure to be cemented, at this end, to the
interior surface of an aircraft skin. Alternately, this end may be
enclosed and detachably mounted to the interior surface of an aircraft
skin by means of ring magnets, as discussed in connection with FIG. 1. The
opposite end 36 of the pick-up unit 19 is closed. An electromagnetic field
is created between the cores 26 and 32 via housings 22 and 30. When the
sending and pick-up units are positioned on opposite sides of an aircraft
skin, the two units are inductively coupled and magnetic flux lines link
the two, as indicated by reference numeral 40.
In order to minimize power dissipation of the coupled signal and power, it
would be preferable to have the area of the aircraft skin between the
sending and pick-up units fabricated from a non-conducting material This
is a preferable design consideration when high frequencies are employed or
otherwise, unwanted eddy currents may develop. In order to maximize the
structural connection of a non-conductive area to a conductive aircraft
skin, a slotted configuration as shown in FIG. 3 may be employed. In this
figure, an area of the aircraft skin 16 has a star-shaped slot 42 cut
therein. The void created is filled with a non-conductive material, such
as fiberglass, so as to completely fill the slot as indicated by reference
numeral 48. The slot itself is characterized by pointed projections 44
interconnected around a circular boundary 46. The utilization of the
pointed projections increases the electrical and electromagnetic
resistance of the aircraft skin in the vicinity of installation for
sending and pick-up units which results in a decrease of power dissipation
between the sending and pick-up units. In addition, the projections serve
to mechanically interlock the non-conductive material 48 to the aircraft
skin 16, this being an important consideration in the harsh environment
encountered along the outer skin of a military high-speed aircraft.
The center of the filled-in slot may have a central spot 50 painted thereon
so as to guide the center placement of the sending unit 14 when data and
power are to be inductively coupled.
Although a simplified inductive coupling is illustrated in connection with
the sending and pick-up units, it is also possible to use multiple coils
to separate the coupled signal and power so that two distinctive coupling
paths are created.
Security of the described system is increased by the random number system
of my co-pending patent application Ser. No. 258,349. In operation of that
system as illustrated in FIG. 4, the operational sequence generally begins
after power is coupled to the internal data memory 12 as previously
discussed. Afterwards, the data generator 10 couples a start command to
the control circuits of memory 12 in a conventional manner. A random
number generator 51 located within the aircraft generates a random number
and outputs it to the pick-up unit 19. Since the pick-up unit and sending
unit are symmetrical and inductively coupled devices, the pick-up unit
acts as a primary at this time, while the sending unit 14 acts as a
secondary. The random number becomes stored in buffer 52 which is located
in the data generator 10. The data stored in memory 55 and the random
number are encoded in an encoder 54 in accordance with a specific
sequence. The encoded data now represents an encryption of the basic data
by the random number. Wire 13 connects the output of encoder 54 to the
sending unit 14 so that the encoded data may be coupled to the pick-up
unit 19. The latter unit then outputs the encoded data to buffer 56 within
the aircraft. A decoder 58 has its inputs 60, 62 respectively connected to
the random number generator and the encoded data buffer so that the
encrypted data may be decoded in accordance with the same specific
sequence governing the encoder 54. The output 64 of the decoder then
delivers the decoded data to the internal data memory 12 for use by other
data or communication equipment on board the aircraft in a conventional
fashion. To further increase the security of communication, it is intended
that each aircraft generate a different random number when the data
generator 10 is coupled to succeeding aircraft.
The present invention is a further improvement of the systems disclosed in
my co-pending applications and provides parallel distribution of data
subsets to a plurality of utilization devices so that any radiated data
signals will be superimposed to produce a resultant jumbled signal which
effectively masks the data of each subset.
In order to better appreciate the concept of the present invention,
reference is made to FIG. 5. As will be seen from the figure, the memory
12 stores a plurality of data subsets in locations 66, 68 and 70, by way
of example. In a preferred embodiment of the present invention, memory 12
is a non-volatile RAM. The data subsets have been provided from the
originating data source, via the sending and pick-up units. Connecting
cables 72, 74 and 76 are connected from respective subset output ports of
memory 12 to corresponding input ports of local memories 78, 80 and 82.
Each of the latter-mentioned local memories serves to store one of the
data subsets for a corresponding utilization device. The indicated
utilization devices 84, 86 and 88 are respectively connected to their
local memories by the parallel connecting cables 90, 92 and 94; and data
will flow therebetween as the utilization devices require. With the
simultaneous parallel flow of data along cables 72, 74 and 76, any
resulting radiation outside the aircraft will be detected, by unfriendly
surveillance, as superimposed unintelligible signals representing the
parallel distributed data subsets. In addition, the noise present along
the various parallel data channels is superimposed to increase the
unintelligibility of the detected signal. Shielded cables 72, 74 and 76
are typically long "spider" cables which have a tendency to radiate
signals; and the present invention is directed to obviate this problem.
Further enhancements for increasing the security of the system are to load
the local memories with the various data subsets at different frequencies
and signal amplitudes. Also, it is possible to encrypt the data as it is
distributed from the memory 12 to the local memories.
As will be appreciated from an understanding of the present invention,
there is offered a parallel data distribution system which creates
electromagnetic radiation characterized as a superposition of the
radiation for corresponding data subsets. A resultant scrambled signal is
difficult, if not impossible to decipher by unfriendly surveillance
equipment. Accordingly, the present invention enhances the security of
data distribution within a military aircraft.
It should be understood that the invention is not limited to the exact
details of construction shown and described herein for obvious
modifications will occur to persons skilled in the art.
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