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Description  |
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BACKGROUND OF THE INVENTION
The present invention relates, in general, to tracking and recovery systems
and systems for tracking and recovering humans. More particularly, it
discloses a system employing a self-powered, self-maintained transceiver,
small enough to be implanted in a human, for locating, tracking, and
recovering persons in distress, such as kidnap victims, people
encountering adverse circumstances while in the wilderness, victims of
heart attacks and the like.
BACKGROUND OF THE INVENTION
Various apparatus and techniques for tracking and locating animate and
inanimate objects are known in the art. Recently, international
legislation has established a satellite tracking system for locating
downed aircraft and distressed seagoing vessels. This system utilizes
user-activated transmitters operating at a frequency of 460 MHz, as
spelled out in the Code of Federal Regulations chapter 47 part 90. These
inexpensive transmitters are known as Emergency Position Indicating Radio
Beacons (EPIRB's). The associated satellite network is capable of locating
a transmitting EPIRB anywhere on the face of the globe. By international
agreement, this system is used only for distressed aircraft and seagoing
vessels, and all other potential uses are forbidden.
U.S. Pat. No. 4,818,998 describes a vehicle tracking and recovery system
employing a transceiver (to be hidden within a motor vehicle), and a
network of fixed and mobile ground transmitters and receivers to
facilitate tracing and recovery of stolen vehicles. This system is
presently in wide use by LoJack Corporation in the United States. The
system operates at a frequency of 173.075 MHz, permanently assigned as a
police radio service frequency in 1992. The unit, mounted in an
automobile, is continuously operated as a receiver until such time as it
is remotely activated, at which time it transmits a radio beacon
(similarly to the EPIRB system), facilitating tracking and recovery. The
tracking and recovery in the LoJack system is accomplished through a
network of ground based fixed and mobile receiver units, which utilize
field strength measurements and directional receivers to locate the
transmitter, as opposed to the timing and triangulation methods used by
the EPIRB system. The receiver in the automobile-mounted unit draws its
power from the vehicle battery, and utilizes a small local rechargeable
battery that powers the unit should the vehicle battery be disconnected.
U.S. Pat. No. 4,706,689, Issued to Daniel Man on Nov. 17th, 1987, describes
a device designed to be implantable behind the ear of a human. The device
transmits a coded signal intended to enable tracking of the person
outfitted with the implanted device. The device operates continuously, and
is designed to be recharged through external contacts. It is also designed
to incorporate a biological monitoring function, such as might facilitate
out-patient monitoring.
The above described devices all have limitations making them unsuitable as
systems for the widespread tracking and recovery of humans. The EPIRB
transmitter and Lojack transceiver are not miniaturized to the point where
implantation is practical. The techniques for manually activating the
EPIRB unit also make it unsuited for implantation. The LoJack unit
requires substantial power to be supplied continually from a vehicle
battery system, and unsuited for implantation from this point of view as
well.
Daniel Man's implantable device is designed for continuous operation, which
places severe constraints on its transmission range, even if it is only to
be operated for a day at a time between battery recharges. With a given
level of background radio frequency noise, communication theory can be
used to calculate the minimum power consumption needed for detection of an
event within a given time to within a given certainty, at a given distance
from an omni-directional transmitter. The resultant average transmission
power is independent of whether the transmitter is pulsed or continuous.
Further problems arise with Man's system when a number of units are in use
in the same area. The tracking problem becomes prohibitively expensive for
many simultaneous units, and the malfunction of any unit can mask the
detectability of other units, or require significantly increased
transmission power levels for all units. Such a system would require a
very expensive closely spaced network of permanent tracking receivers with
very costly hardware capable of tracking multiple units at one time. A
system where transmitters are active all the time requires n times more
bandwidth in the radio spectrum than minimal-bandwidth system with only
one transmitter transmitting at one time. The availability of bandwidth
could become quite a problem if the Man system were put into wide use.
In addition, the implanted unit would need to be recharged (probably daily)
through contacts brought out through the person's skin. Such an
arrangement presents a significant health hazard. In addition, the need
for regular recharging puts significant restraints on the person using the
device and also heightens the users awareness of the implanted device,
resulting in a less "free and natural" state of mind. The complexity of
the Man system could result in a significant level of false alarms, and/or
prohibitively high cost.
The present invention contemplates improving upon the features available in
the aforementioned devices and makes possible a widespread tracking and
recovery system for humans in distress. The present invention will benefit
from novel features allowing it to remain implanted and functional for
many years. The device will remain in a dormant state until activated,
either by the person in whom it is implanted, or by remote means. Novel
means for powering and triggering the device will make recharging and
battery replacement unnecessary. The device meets the growing demand for a
new level of safety and peace of mind.
Consequently, it is a general object of this invention to provide a new
means and method for locating, tracking, and recovering humans in
distress. Ideally, the device will bring peace of mind and an increased
quality of life for those who use it, and for their families, loved ones,
and associates who depend on them critically. Adults who are at risk due
to their economic or political status, as well as their children who may
be at risk of being kidnapped, will reap new freedoms in their every-day
lives by employing the device. Law enforcement agencies will be able to
more economically protect those at risk, those who would potentially
perpetrate acts of violence against individuals will be more effectively
deterred. Those who enjoy wilderness sports such as mountain climbing,
skiing, hang gliding, etc. will enjoy new freedom knowing that a rescue
mission can be dispatched to their exact location if they encounter
trouble.
A specific object of the invention is the rapid effective recovery of
individuals who have been kidnapped. A further object of this invention is
to afford peace of mind and increased quality of life to those utilizing
the invention, and to their loved ones and dependent associates. It is a
further object of the invention to make emergency aid readily available to
those at risk in remote or urban areas. It is a further object of the
invention to reduce the cost of rescue missions to remote areas. It is
further object of the invention to facilitate a highly reliable, minimal
cost, location and recovery system with flexible features. It is a further
object of the invention to facilitate rapid, automatic deployment of
medical personnel in the event of certain medical emergencies.
This implantable tracking and recovery device makes possible greatly
increased safety for people in a variety of situations. This increased
safety leads to peace of mind and associated increased quality of life not
only for those utilizing the device but for concerned loved ones as well.
Four areas where this device will be seen to have significant impacts are
(1) safeguarding against kidnapping, and rapid recovery of victims; (2)
safety in wilderness sporting activities, where risk is inherent and help
is often not readily available; (3) personal safety in urban environments,
where one might encounter car-jackings, muggings, and the like; (4)
medical emergencies, such as heart attack or seizure.
The lives of potential kidnap victims and their loved ones will be
significantly freed up by the peace of mind afforded by the tracking
device. Along with peace of mind, the homing device will offer the
possibility of a lifestyle that would otherwise be considered too risky.
In the event of a kidnapping, law enforcement officials could be
expediently dispatched for rapid recovery of the victim.
The tracking device will offer safety in such activities as hiking,
mountain climbing, skiing, and camping in remote areas. Costs of rescue
missions will be dramatically cut because searching will not be necessary.
Lives will be saved because the time from when the emergency occurs to
when help arrives will be dramatically cut.
The device will afford increased safety and peace of mind for those in
urban areas as well. The increase in gang violence, rapes, muggings, and
car jackings in recent years has generated significant increased concern
for personal safety. The use of the device will afford increased peace of
mind and will allow law enforcement to be more effective.
Many lives could be significantly prolonged if help were rapidly available
in the event of a heart attack. Unfortunately, the individual suffering
the heart attack may not recognize the symptoms of the heart attack (which
may occur in sleep), and even if the symptoms are recognized, the
individual may be unable to summon help. The use of the device with
incorporated body-function monitoring capability allows help to be rapidly
dispatched, potentially saving the life of the user.
SUMMARY OF THE INVENTION
The system employs triggerable radio beacon transmitter means designed to
be implanted beneath the skin of an individual. Biological monitoring in
the device will provide means for rapidly dispatching help in the event of
a detectable medical emergency, such as a heart attack. A unique
sensation-feedback feature allows the user to control and trigger the
device with certainty, resulting in a more reliable, easily maintained
system. The device is hermetically sealed in a biologically inert
container. The device operates normally in a dormant state, and can be
externally triggered to transmit the homing beacon. There are numerous
possible embodiments of the trigger mechanism. In some embodiments of the
trigger mechanism, the device is designed to be remotely triggered. Such a
feature is desirable if the device is implanted in a small child who
cannot be relied upon to trigger the device. Remote triggering may also be
desirable in instances when an individual may be unconscious.
In one remote triggering instance, a radio transmitter may broadcast a
coded signal to a receiver within the device. The receiver is equipped
with circuitry for recognizing the coded radio signal. In one embodiment
where the device is locally triggered, the device may be equipped with an
acoustic receiver designed to detect certain sounds or a predetermined
sequence of sounds in time, such as a note progression. In this case the
device would likely be triggered by the person in whom it is implanted,
for instance by humming a given tune. Immunity to false alarms may be
provided by making the sequence long or requiring it to be repeated in a
certain amount of time.
In another embodiment, the device may be triggered by monitoring a body
function such as heart rate. If the victim were to experience a heart
attack, help would be automatically and expediently dispatched.
If the device is triggered either by an external coded radio signal or a
coded acoustic signal, or by monitoring a body function such as heart
rate, the device incorporates a micro-power analog electronic means such
as a radio or acoustic receiver or electrocardiogram monitoring circuitry,
which runs off energy collected either from body muscle by
electromechanical means, or from an external charger through
electromagnetic induction coupling.
Other local triggering means not requiring a micro-power receiver are also
contemplated. In such a case the device may be triggered by
electromechanical means with a binary output, such as a mechanical switch.
Possible embodiments of such a triggering mechanism range from a simple
subcutaneous switch or combination of switches that actuate the
transmitter when pressed, to an actuator coupled to internal body muscle,
combined with digital circuitry designed to trigger the transmitter in
response to a timed sequence of actuations.
It may be desirable in some implementations to include capabilities for
both local and remote triggering. The same individual may desire the
capability of local triggering in the event of an emergency such as a
car-jacking, mugging, or kidnapping, while desiring remote triggering
capability if for some reason the situation had rendered the individual
unconscious. It may also be desirable in some embodiments for the user to
be able to disable the remote-trigger feature.
The device contains a power source capable of supplying power for the
transmitter for ample time to afford recovery of the individual in
distress. Once triggered, the device may transmit only for a predetermined
interval, allowing re-triggering later if the distressed individual is not
located, or if help takes some time to dispatch.
The small size of the device makes it suitable for implantation in young
children as well as adults. The above and other features of the invention
including various and novel details of construction and combination of
parts will now be more particularly described with reference to the
accompanying drawings and pointed out in the claims. It will be understood
that the particular personal tracking and recovery system embodying the
invention is shown by way of illustration only and not as a limitation of
the invention. The principles and features of this invention may be
employed in varied and numerous embodiments without departing from the
scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts an overall schematic view of a system for the tracking,
locating, and recovery of humans embodying the features of the invention
and including an exemplary implantable triggerable transmitting device,
remote activation transmitter, several ground-based receiving antennae and
alternate satellite-based receiving antennae, mobile receiving unit, and
associated coordinating equipment, which combine to perform the locating
and tracking function.
FIG. 2 is a schematic block diagram of an illustrative implantable
triggerable transmitter unit, including sensation feedback feature, and
several trigger implementations, which are used separately or in
combination in a given embodiment of the implantable device.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, one of a plurality of persons, P.sub.1, is equipped
with an implanted transceiver device D.sub.1 from a plurality of devices
D. A plurality of triggerable transmitters T (only one of which is shown
in FIG. 1) transmit a coded trigger signal S.sub.1, which is picked up by
the receiver section of all implanted devices D (only device D.sub.1 being
shown in FIG. 1). The receiver circuits in all devices D receive the same
coded trigger signal. However, the code in signal S.sub.1 uniquely
identifies device D.sub.1, and D.sub.1 alone responds to coded signal
S.sub.1 by transmitting a locating-and-tracking signal S.sub.2. Signal
S.sub.2 is received by at least one ground-based receiver, A.sub.1,
A.sub.2, and A.sub.3, of a plurality of receivers A, or at least one
satellite receiver including SR.sub.1, SR.sub.2, and SR.sub.3 of a
plurality of receivers R.
Information from the ground-based receivers A or the satellite receivers S
are coordinated at a tracking and locating center TLC. Equipment within
the tracking and locating center TLC uses information (for example phase,
timing, field strength, etc.) of the received signals to derive positional
information about implanted device D.sub.1. Additional positional
information may be provided by a mobile receiver MR, which may employ
directional receiving means DR, and one or more antenna MA. The mobile
receiver MR may be used, for instance, to locate implantable unit D.sub.1
within a building, a neighborhood, or a small area of wilderness,
facilitating cost effective recovery without having to map the face of the
globe precisely.
Upon being triggered by signal S.sub.1, implanted device D.sub.1 preferably
transmits only for a brief interval long enough to get a rough positional
fix. When the mobile receiver MR has been dispatched, or other rescue
means have been readied, transmitter T would then re-activate implanted
device D.sub.1 for the second stage of the recovery.
FIG. 2 is a mechanical and electrical schematic block diagram of an
exemplary implantable triggerable transceiver unit D.sub.1. The entire
unit D.sub.1 is housed within a sealed case and designated 39. The case is
preferably made from or covered with a biologically inert material such as
Teflon or Titanium. Several possible mechanisms are shown. Remote radio
receiving means comprise a receiving antenna 2 and micro-power radio
receiver/demodulator means 4. The triggering signal S.sub.1 is received by
antenna 2, and the resultant electrical signal is fed to the micro-power
radio receiver/demodulator means 4, which outputs a binary signal S.sub.3
to signal decoder means 6. The signal decoder means 6 monitors signal
S.sub.3 over time, and upon detecting a certain pre-determined pattern,
sends a trigger signal S.sub.5 to timing circuit means 8. Timing circuit
means 8 then applies a control signal S.sub.6 to a power switching means
7, causing power switching means 7 to apply power from power source 14 to
a beacon transmitter 10, which may broadcast at different power levels,
controlled by signal decoder means 6.
The beacon transmitter 10 operates in response to being actuated by power
source 14, and transmits the locating and tracking signal S.sub.2 via
transmitting antenna 12. Through the incorporation of proper input
protection circuitry on the micro-power receiver 4, it is possible for
receiving antenna 2 and transmitting antenna 12 to be one and the same.
These antennae are shown as being separate in FIG. 2 for functional
clarity. The micro-power receiver means 4 is powered by energy storage
means 36. Micro-power generating means 26 may derive power from some
energy source external to the implanted device.
In the preferred embodiment, micro-power generating means 26 derives power
from physical work done by muscle fibers in the body. Body muscle 30 is
connected (for instance, via suturing) to linkage 28. Linkage 28 connects
muscle 30 through a seal in case 39 to micro-power transducing means 26.
Case 39 is mechanically anchored to another body structure (for instance
muscle, tendon, bone, etc.) to afford an opposing force to that exerted by
muscle 30. Power transducing means 26 converts the work of muscle 30 to
useful electrical energy, which is fed to energy conversion circuitry 32.
Energy conversion circuitry 32 is provided to most efficiently store the
electrical energy derived from power transducing means 26 in energy
storage means 36. Energy storage means 36 serves as an energy reservoir
for micro-power circuitry 34. Micro-power receiver 4 may be implemented
similarly to receiver sections used in miniature commercial pagers. Power
transducing means 26 may be a piezoelectric device (the preferred
embodiment), electromagnetic induction device (such as a moving magnet
generator), or the like. Linkage 28 is preferably sealed to case 40 with a
flexible membrane.
Energy storage means 36 holds enough energy to sustain micro-power
circuitry in an operational state with enough regularity to insure proper
triggering of beacon transmitter 10 in response to trigger signal S.sub.1.
The duty cycle requirements of the availability of power from energy
storage means 36 may be traded off against the length of time the
activation signal S.sub.1 is sent out. In the preferred embodiment, there
is enough power available from energy reservoir 36 to power micro-power
receiver/demodulator means 4 100% of the time.
Power-switching means 7 is shown as a field-effect transistor, chosen in
the preferred embodiment because it takes no static power to keep turned
on, yielding easy interface with micro-power circuitry, and also allowing
a high degree of integration onto a single chip. Signal decoding circuitry
6 and timing circuitry 8 are preferably CMOS logic, in order to draw
minimal power. Timing circuitry 8 is preferably powered from power source
14, in order that brief lapses in the availability of power from energy
storage reservoir 36 will not affect the timing of beacon transmitter 10.
Signal decoder means 6 may be made capable of detecting multiple codes to
perform different functions, for instance to activate beacon transmitter
means 10 for different periods of time. A short-time actuation might be
desirable for an initial positional fix, and a long-time actuation might
be desirable for a final local recovery by a mobile receiver. It is
desirable to have different activation codes result in beacon transmitter
10 being energized at different power levels, for instance a high power
level for the initial positional fix, where the receiving antennae may be
far away, and a lower power level during the final positional
determination by a mobile receiver.
Binary conversion means 38 converts the analog signal derived from power
transducing means 26 to a digital signal. In the preferred embodiment,
this enables body muscle 30 to be used to control the implanted device as
well as provide power to the device. Contractions of body muscle 30 cause
alternating voltage signal S.sub.5 to be generated and applied to energy
conversion circuitry 32 and binary conversion means 38. For the
piezoelectric power transducing means of the preferred embodiment, binary
conversion means 38 may be implemented as a voltage divider means 24
followed by Schmitt trigger means 22. Binary conversion means 38 is
powered by energy storage reservoir 36, in order to avoid draining the
standby power source 14. The output of binary conversion means 38 feeds an
input on signal decoder means 6 with a digital signal, allowing signal
decoder means 6 to be entirely digital CMOS circuitry such as common in
wristwatches, which can be made to draw so little power that the drain on
power source 14 would be inconsequential, even over a number of years.
Signal decoder 6 may provide different decoding functions for data streams
from different sources. For instance, signal S.sub.4, derived locally, may
be decoded to provide functions not accessible remotely, such as shutting
down micro-power receiving means 4. This may be desirable if the user is
worried about being locatable by an adverse party under certain
circumstances. Partial completion of the trigger code in data stream
S.sub.4 may be programmed to provide a perceivable sensation to the user,
for instance through vibrator means 20. This would provide means for
"practicing" triggering the device without actually sending out a signal
indicating an emergency. It is also possible to configure the device to
provide the same or different perceivable sensation through vibrator means
20 upon activation of Beacon transmitter 10. This feedback would provide
peace of mind to the user, knowing that help was on the way. Various
self-test functions may be implemented through special codes recognized in
signal stream S.sub.4.
Voltage monitor means 16 is provided to detect a low-energy state of power
source 14. Voltage monitor means 16 is preferentially powered off energy
reservoir 36, ensuring that the critical standby power source 16 is not
drained by providing the voltage monitoring function. Voltage monitor
means 16 may also activate vibrator means 20 in such a way as to provide a
sensation uniquely indicating low power.
It is contemplated that in one embodiment, energy reservoir 36 and power
source 14 would be one and the same. This has not been done in the
preferred embodiment for three reasons: First, the most suitable
embodiment of power source 14 is deemed to be a chemical storage battery
with a long (perhaps 10 year) expected shelf life. This ensures that
adequate power for beacon transmitter 10 is available reliably, while
taking very little space. Second, regular "playing" with vibrator means 20
could, in such an instance, result in substantially draining power source
14 for some period of time. Third, implementing energy reservoir 36 with a
different type of energy storage device than 14 (for instance,
implementing 36 as a capacitor) can allow for increased charging
efficiency over the relatively low electrochemical charging efficiency of
many batteries.
For very long term applications or to reduce the shelf life requirements on
power source 14, voltage regulator means 18 may be provided to use surplus
energy collected from power transducing means 26 to keep power source 14
optimally charged.
It may be desirable to separate the receiving and/or transmitting antennae
2 and 12 from the rest of the unit, in order to allow the antennae to be
closer to the surface of the body for more efficient transmission and
reception. Such mechanical alterations to the containment of the device
are within the scope of the present invention.
It is also possible for the conversion circuitry 32 to receive power from a
source external to the body, such as an electromagnetic induction source
that might be placed close to the body on a regular basis for purposes of
recharging energy reservoir 36. In such an embodiment inductive pickup
means 40 receives electromagnetic energy from a source external to the
body. Such implementation is considered less desirable because it affords
the user less personal freedom, and results in a system which is less
robust overall.
The drawings referred to in the specification are presented in block
diagram form. Numerous possible implementations of any given block will be
apparent to one skilled in the art. Any specific details referred to are
strictly by way of example. It will be readily apparent to one skilled in
the art that various substitutions and modifications can be made without
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