U.S. patent application number 11/901496 was filed with the patent office on 2008-05-01 for personal sonar system.
Invention is credited to Matthew Pope.
Application Number | 20080101159 11/901496 |
Document ID | / |
Family ID | 35425038 |
Filed Date | 2008-05-01 |
United States Patent
Application |
20080101159 |
Kind Code |
A1 |
Pope; Matthew |
May 1, 2008 |
Personal sonar system
Abstract
The sonar device includes a sonar transducer, a noise filter, a
microprocessor and an output device. The system warns the user when
a hazardous objects is detected or when signals from companions
decrease. The portable sonar device can be built into various
watersport devices including scuba diving equipment, surfboards and
windsurfboards.
Inventors: |
Pope; Matthew; (Los Angeles,
CA) |
Correspondence
Address: |
DERGOSITS & NOAH LLP
FOUR EMBARCADERO CENTER, SUITE 1450
SAN FRANCISCO
CA
94111
US
|
Family ID: |
35425038 |
Appl. No.: |
11/901496 |
Filed: |
September 17, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11546160 |
Oct 10, 2006 |
7272075 |
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11901496 |
Sep 17, 2007 |
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11053789 |
Feb 9, 2005 |
7145835 |
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11546160 |
Oct 10, 2006 |
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60543579 |
Feb 10, 2004 |
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Current U.S.
Class: |
367/131 |
Current CPC
Class: |
Y10S 367/91 20130101;
G01S 15/96 20130101; G01S 7/521 20130101; G01S 7/539 20130101; B63C
11/26 20130101; G01S 7/56 20130101; G01S 7/64 20130101; B63C 11/48
20130101; G01S 15/86 20200101 |
Class at
Publication: |
367/131 |
International
Class: |
G01S 15/00 20060101
G01S015/00 |
Claims
1. A sonar device having: a transmitter that emits sonar signals; a
receiver that receives sonar signals and emits electrical signals;
a memory that stores ambient noise for a body of water; a database
of signals representing a plurality of identifiable types of fish;
an electronic filter that removes ambient noise from the electrical
signals; a GPS receiver that provides location data for the sonar
device; a microprocessor that interprets filtered electrical
signals and compares the filtered electrical signals to the
database of signals representing the plurality of identifiable
types of fish; and an output device that emits a signal that
includes the location data when the filtered electrical signal
corresponds to at least one of the signals representing the
identifiable types of fish.
2. The sonar device of claim 1, wherein the ambient noise for a
body of water stored in memory is replaced with a second ambient
noise for a second body of water.
3. The sonar device of claim 1 wherein the sonar device further
comprises: a solar panel for providing electrical power to the
sonar device.
4. The sonar device of claim 1 wherein a depth signal is an input
to the microprocessor.
5. The sonar device of claim 1 wherein the electronic filter
includes an ambient signal which is recorded by the user.
6. The sonar device of claim 1 wherein the electronic filter
includes a recording of ambient signals in a body of water.
7. The sonar device of claim 1 wherein some components of the sonar
device are mounted within a waterproof housing.
8. The sonar device of claim 1 wherein the transmitter and the
receiver are mounted on an external surface of a boat.
9. A sonar device having: a transmitter that emits sonar signals; a
receiver that receives sonar signals and emits electrical signals;
a memory that stores ambient noise for a body of water; a database
of signals representing a plurality of fish; an electronic filter
that removes ambient noise from the electrical signals; a GPS
receiver that provides location data for the sonar device; a
microprocessor that includes a neural network for interpreting the
electrical signals and comparing the filtered electrical signals to
the database of signals representing the plurality of fish; and an
output device that emits a signal that includes the location data
when the filtered electrical signal corresponds to at least one of
the signals representing the identifiable types of fish.
10. The sonar device of claim 9, wherein the ambient noise for a
body of water stored in memory is replaced with a second ambient
noise for a second body of water.
11. The sonar device of claim 9 wherein the sonar device further
comprises: a solar panel for providing electrical power to the
sonar device.
12. The sonar device of claim 9 wherein a depth signal is an input
to the microprocessor.
13. The sonar device of claim 9 wherein the electronic filter
includes an ambient signal which is recorded by the user.
14. The sonar device of claim 9 wherein the electronic filter
includes a computer program that records an ambient signal while
the sonar device is in a body of water.
15. The sonar device of claim 9 wherein some components of the
sonar device are mounted within a waterproof housing.
16. A sonar device having: a transmitter that emits sonar signals;
a receiver that receives sonar signals and emits electrical
signals; a database of signals representing a plurality of
identifiable types of fish; an electronic filter that removes
ambient noise from the electrical signals; a GPS receiver that
provides location data for the sonar device; a microprocessor that
interprets filtered electrical signals and compares the filtered
electrical signals to the database of signals representing the
plurality of identifiable types of fish; and an output device that
emits a signal that includes the location data when the filtered
electrical signal corresponds to at least one of the signals
representing the identifiable types of fish.
17. The sonar device of claim 16 wherein the sonar device further
comprises: a solar panel for providing electrical power to the
sonar device.
18. The sonar device of claim 16 wherein a depth signal is an input
to the microprocessor.
19. The sonar device of claim 16 wherein the electronic filter
includes an ambient signal which is recorded by the user.
20. The sonar device of claim 16 wherein some components of the
sonar device are mounted within a waterproof housing.
Description
[0001] This is a continuation of U.S. patent application Ser. No.
11/546,160, filed Oct. 10, 2006, now U.S. Pat. No. 7,272,075 which
is a continuation of U.S. patent application Ser. No. 11/053,789,
filed Feb. 9, 2005, now U.S. Pat. No. 7,145,835 which claims
priority to U.S. Provisional Patent Application No. 60/543,579
filed Feb. 10, 2004.
BACKGROUND
[0002] Sonar (SOund NAvigation Ranging) technology is used to
detect objects under the water. A sonar device emits acoustic
pulses in water and receives an echo from any objects that the
acoustic pulse reflects back from. The distance between the sonar
device and the object can be determined by measuring the time
between the pulse transmission and reflected pulse reception.
Active sonar creates a pulse of sound, often called a "ping", and
then listens for reflections of the pulse. To measure the distance
to an object, one measures the time from emission of a pulse to
reception. The acoustic pulse travels at the speed of sound
underwater, thus the distance is determined by the (speed of
sound)/(time between sending and receiving the pulse/2).
[0003] The pulse may be at constant frequency or a chirp of
changing frequency. For a chirp, the receiver correlates the
frequency of the reflections to the known chirp. The resultant
processing gain allows the receiver to derive the same information
as if a much shorter pulse of the same total energy were
emitted.
SUMMARY OF THE INVENTION
[0004] The present invention is a personal sonar system that can be
used in most water sport applications and comprises a sonar
transducer, a processor and an output device. In a surfing
embodiment, the sonar device is integrated into the user's
surfboard. In a preferred embodiment, the sonar transducer is
mounted at the back end of the board and emits a wide angle sonar
signal which will detect large moving underwater animals including
predatory fish. Electrical signals from the transducer are filtered
to remove background noise which is caused by the movement of the
surfboard due to ocean swells and stationary underwater objects on
the sea floor. The electrical filter can be frequency based or may
be a software algorithm running on a microprocessor. The algorithm
may be a neural network or an adaptive system. The signal alerts
the user when a large underwater animal is detected. The alert
signal may be an optical light signal or an audio signal. The light
and/or speaker may be mounted on the upper front surface of the
surfboard which is easily noticeable to a surfer sitting on the
rear of the board waiting for a wave to ride.
[0005] In another embodiment, the sonar unit may be mounted in a
self contained housing for use by snorkelers and scuba divers. In
underwater embodiments, the system not only detects large animals
but also the separation from companions. The system detects the
normal presence of companions based upon the reflected sonar signal
or the detection of signals from the companions' sonar devices.
When a companion signal grows faint, the system emits a warning
signal to alert the user of separation. By knowing when a companion
has separated from the group it becomes much easier for the user to
start looking immediately for the companion. This can be
particularly useful in low visibility situations such as night or
cave diving.
[0006] In order to improve accuracy, the inventive system has an
ambient calibration mode that allows the user to calibrate the
system on site to the ambient underwater sounds. When a user enters
the water, the area can be visually scanned for large animals. The
close presence of large underwater animals is rare, thus the system
user is normally safe. Every body of water has unique acoustic
characteristics by tuning the unit to the specific location, the
accuracy of the detection is improved. During any safe period, the
unit can be set to calibration mode. The sonar unit transmits
signals and detects the ambient reflected signals. This ambient
signal is stored in the system's memory and used to calibrate the
sonar system. This calibration mode allows the inventive sonar
system to adapt to the location of the user and provides
substantially enhanced detection accuracy. After calibration, the
system is able to more easily detect unusual objects in the
vicinity such as sharks.
[0007] The inventive unit can also be used to detect the presence
of companions who need to stay in the proximity of the user. This
function is important to avoid separation or be notified of
separation from a group. The system may also have a companion
calibration mode that allow the user to calibrate the sonar unit to
detect companions on site. The companion detection mode is similar
to the calibration mode. When the user is in the water, the user
can actuate the companion calibration mode. The system detects the
normal reflected signals produced by all companions or signals
emitted by each companion and learns to recognize the companion
signals. The companion system detects when any companion signal
gets faint and warns the user of a companion's separation from the
group while in the water.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is an illustration of the basic components of the
inventive sonar device;
[0009] FIG. 2 is an illustration of a scuba diver using the
inventive handheld sonar device;
[0010] FIG. 3 is a top view of the handheld sonar device;
[0011] FIG. 4 is a side view of the handheld sonar device; and
[0012] FIG. 5 is an illustration of a surfboard that incorporates
the inventive sonar device.
DETAILED DESCRIPTION
[0013] The present invention is a waterproof sonar device for use
while surfing, scuba diving or other water sports. The inventive
sonar device is used to locate sharks and other large animals. With
reference to FIG. 1, the basic components of the sonar device
include a transmitter 103, a transducer 105, a receiver 107, a
display/user interface 109 and microprocessor 115. The
microprocessor 115 instructs the transmitter 103 to emit sound
waves 111 that are sent through the water 113. When the sound wave
111 strikes an object 117, it rebounds and returns to the
transducer 105, after which it is converted back to an electrical
signal that is amplified by the receiver 107 and the detected
signals are processed by the microprocessor 115. The display/user
interface 109 keeps the user apprised of the current operating
conditions and warns the user of large objects in the area as well
as the separation of divers.
[0014] The distance to an object can be determined based upon the
time it takes for the signal to travel to an object and to return
to the source. Since the speed of sound in water is relatively
constant at approximately 4,800 feet per second, there is a direct
relationship between time and distance. This process is repeated
many times per second. In an embodiment, the microprocessor may
include electronic memory such as a flash memory card or dynamic
random access memory (RAM). These components are powered by
electrical power which is normally supplied through a rechargeable
battery. In an alternative embodiment, solar cells may be used as
the primary power source or as a means of recharging the battery.
The battery may also have a water proof connector which allows the
batter to be recharged through household electrical power when the
device is not in use. The battery may also be magnetically coupled
to the recharger so that a direct electrical contact is not
required. The battery may also be attached to the weight belt.
Because the batteries are heavy, they can replace many of the lead
weight typically used in a weight belt for neutral buoyancy.
[0015] In an embodiment, the present fish detection invention uses
a portable sonar (an acronym for "SOund, NAvigation and Ranging")
device to detect objects such as large fish or sharks in proximity
to the user. The devices are suitable for the sonar device include,
surfboards, scuba equipment, windsurfers, boats and handheld
underwater devices. The invention allows the individual to detect
or be alerted to the presence of a large fish so that evasive
action can be taken. By detecting the presence of sharks, severe
personal injury may be avoided. Sonar transducers come in many
forms and are mounted on a surface that is submerged in the water.
Each transducer is rated by the degree of cone angle. In general, a
wide cone angle gives better results in shallow to medium depths
while the narrow cone angle penetrates better to deeper depths but
doesn't show as many fish or as much structure due to its narrow
beam. Thus, for surfboards which are used primarily in shallow
water a wide angle transducer may be more suitable than a narrow
beam transducer. However in an embodiment, the device may have both
narrow and wide angle transducers or more that the user can switch
between or operate simultaneously. A single beam may cover a 16-24
degree range. A concentric dual beam system uses a first narrow
center beam can be used within a second beam of 53 degrees that
surrounds the first beam expanding the coverage. A three beam
system uses three sonar beams to form a 90 degree detection range.
The transducer may even be configured in an array with columns of
multiple transducers.
[0016] The transducers may be configured to the behavior patterns
of the fish to be detected. For example, sharks such as great
whites frequently swim below the fish that are at the surface of
the water that they are about to eat. They then swim upward when
attacking. This provides good contrast of light around the target
for the shark which has poor eyesight. Thus, if the invention is to
be used to detect sharks in an application such as a surfboard, the
transducers should be facing an area directly below the user.
[0017] In an embodiment, the sonar unit components include a
high-power transmitter, an efficient transducer, a sensitive
receiver and a high resolution/contrast display. The high
transmitter power results in a strong signal returned to the unit.
This is important in deep or poor murky water conditions.
Additionally, the increased power allows the detection of more
distinct object detail. The sonar units used and the housing (type
and material) can determine which type of transducers are used. The
transducer must be submerged in order to function. This is most
likely from the transom area of the boat or the rear areas or fins
of a surfboard or windsurfboard. The receiver dampens extremely
strong signals and amplifies small signals in order to get an
effective readout. It must also have the capability to separate
small targets that are close together into distinct, separate
impulses for the display as well as not interpreting non-mobile
objects as fish. The transducers can also be sequentially triggered
to conserve energy and scan a wide area around the user.
[0018] The sonar transducer draws electrical power from a battery
or solar cell and produces signals that are directed towards the
area of interest. These signals are reflected by the objects in the
path of the signals. The sonar transducer also receives the
reflected signals as well as other signals in the target frequency
range. The transducer converts the acoustic signals into electrical
signals that are forwarded to a signal processor. The signal
processor filters the transducer signals so that signals from
target objects are detected while the ambient non-target objects do
not produce false detection readings. This filtering device may be:
frequency/amplitude based, an adaptive algorithm, a adaptive neural
network which analyzes a number of input signals or any other
filter that can remove ambient signals. In a simple frequency based
filter mechanism, the system removes high frequency signals from
small fish and high amplitude signals from fixed large objects such
as the ocean floor while in low depth waters. An adaptive filter
detects changes in the input signals and adapts to these changes.
By adapting to changes in ambient sonar signals, the inventive
system will remain accurate as the diver travels from shallow to
deep water to wreckage areas. In the neural network embodiment, the
system may utilize additional input information such as
temperature, depth, GPS location, etc and use this information in
addition to the sonar signals to more accurately filter the
transducer signals. By filtering out these ambient and benign
signals, the system can leave a specific frequency range open to
detect potentially threatening fish or moving objects.
[0019] In another embodiment, the system uses a broadband sonar
transmission. Broadband echoes contain more information because
they encompass frequencies that provide greater backscatter within
one fish species relative to others. A broadband sonar transceiver
generates analog echoes, amplifies the echoes, tunes the echoes for
the frequency response of the transducer, and transmits the
resulting echo from the transducer. Each "ping" represents 100,000
data points. The system typically sends one ping per second. The
transducer collects the analog echo returns, applies amplification
with adjustable gain to the echoes, and bandpass filters the
echoes. The transducer must pass the echoes to an A/D converter
capable of sampling at thousands samples per second to satisfy the
sampling criteria and to achieve sufficient amplitude range and
resolution.
[0020] For these broadband sonar signals, a digital processor
filters the broadband echoes to produce frequency spectra. Spectral
processing provides a representation of fish not available to
existing fish finding sonar systems. Prior art sonar fish finding
devices use time-domain processing that counts and integrates
echoes. Using spectral decomposition, it is possible to determine
which frequencies are most strongly reflected by the fish targets.
The spectral information is presented to a neural network
classifier which is used to identify specific objects. In the sonar
sense, different size or species fish reflect a broadband
illumination at specific frequencies. Further sonar data has been
collected for various types of sea creatures. By using the proper
frequency and identifying the reflected signal pattern, the
inventive sonar device can be tuned to detect the bladder of
specific types of fish. Broadband sonar techniques are able to
identify frequency-dependent fish bladder resonance for several
species of fish. This can be particularly useful for identifying
hazardous fish such as great white sharks and filtering out all
other reflected signals.
[0021] The signal signatures of fish are created and stored as
fuzzy neural network coefficients in a database. These fuzzy neural
network coefficients may include: sharks, eels, sea snakes, whales,
sea elephants, motor boats, jet skis, submarines, etc. The signals
detected by the sonar transducer are compared to the database of
stored signals by the processing system. This comparison process
includes data analysis steps, including performing feature
extraction to measure specific characteristics of the echo. The
system produces digital echoes to determine whether the sonar pulse
has bounced off an object and returned. The system also uses
feature information in the fuzzy neural network to determine the
type object. In the object identification embodiment, the system
may include: a data acquisition processor (DAP), an
analog-to-digital (A/D) converter with an onboard microprocessor,
that permits the PC-based system to handle the massive amount of
data generated by sonar transmissions. If the system detects a
matching signal, a warning signal is sent to an output device.
[0022] The digital processor filters may also include a calibration
mode which allows the system to detect the ambient noise from the
user's location and more accurately determine true hazardous
objects. In order to use the calibration mode, the user must first
determine that the area of water is free of hazardous objects. This
is normally done by visually checking the surrounding area. The
system then transmits sonar test signals and records the reflected
signals. These reflected signals represent the ambient noise for
that area. After calibration, the system filters the signals by
removing the ambient noise. This allows the inventive sonar system
to adapt to the ambient conditions of any area of water and provide
more accurate detection results.
[0023] The output device can be any mechanism that will alerts the
user. Output devices include: a visual display, an acoustic device,
a vibration device or any other device which emits a signal that
the user can detect. The visual display may be a blinking high
visibility light, an LCD screen that shows proximity and movement
of the object relative to the user or any other optical signal that
can be detected by the user. An acoustic signal may also warn the
user of a close proximity object. The acoustic speaker may be
underwater or a normal air type speaker depending upon the
application. The signal must be in the frequency range of the human
ear. The signal can be a series of pulses or any other type of
alarm sound. The vibration output requires a motor that causes the
device to vibrate when actuated. The user senses the vibration when
the device is in direct or indirect contact with the user.
[0024] Power to the inventive system can be provided by
rechargeable batteries and/or solar cells depending upon the
application. In a surfboard embodiment, the board is exposed to sun
and solar cells can be used. Similarly, solar cells may also be
used by snorklers who are in shallow waters in sunny conditions.
The solar cells may be used to recharge the batteries so that the
device is still active when the solar cell is in a shaded area.
Solar cells may not be useful for many scuba divers because the
water depth reduces the light rays that can reach the divers.
Batteries are can be very heavy, however divers typically carry
weight belts. Thus, the weight of the batteries can be used instead
of weights on the weight belt to help submerge the diver.
[0025] In another embodiment, the system can also be used to detect
the presence of companions. This feature is particularly useful
when it is desirable to keep a group of people together. The
inventive system warns the user when a companion has strayed from
the group. The feature detects the presence of companion by their
reflected sonar signal or by a signal emitted by each of the
companions. The system can be set to calibration mode where the
system emits a test signal and records the reflected signals from
the companions or the system records sonar signals emitted by the
companions. After calibration, the user and companions can travel
underwater with the system monitoring the presence of the
companions by their sonar signals. If the system does not detect a
strong companion signal, it alerts the user. The user can then stop
and look for the companion to keep the group together.
[0026] In different embodiments, the inventive system can be
integrated into various water sport devices. For example with
reference to FIG. 2, the system can be used with surfboards 241 to
warn the surfer of sharks in the area. The sonar device is self
contained and would be installed in a hole or recess formed in the
surfboard 241. In this embodiment, the sonar transducer 245 is
integrated into the tail section on the bottom of the board 241
with sensor aimed straight down. The warning output device 247 is
mounted on the top front of the board 241 where the user can see
and hear the warnings while sitting or laying on the board 241. The
battery may be a solar cell 249 on the top of the board 241 and/or
a battery built into the board 241.
[0027] With reference to FIG. 3, the inventive device may be a hand
held device 361 contained in a waterproof and pressure proof
housing. In this embodiment, the device 361 can be held by a diver
365 to locate sharks and other large animals. With reference to
FIG. 4, the device 361 may have a high resolution LCD or a
fluorescent cold cathode backlit screen 471 that would show
proximity of animals to subject. The device 361 also has a hand
grip 431, a control panel 493 and control buttons 475 that are part
of the user interface and allow the user to control the operation
of the device 361. For example, a control button 475 may be used as
a gain adjustment to filter out "false" readings. There would be an
option to use a backlit screen 471 for use in limited light
situations such as night dives. Power would be supplied by
rechargeable DC batteries 479 that are carried in the weight belt
477 or disposable batteries. The battery pack 479 may be a separate
unit connected to the system 361 with a waterproof cable 451 or
integrated into the system. This device 361 would be directional
and would not be passively active. As optional features, a GPS
device and/or a radio may also be integrated into the device 361.
With reference to FIG. 4, the system 361 may have a cover 591 that
flips up to allow the user access to the screen 471, control panel
493 and control buttons 475 in the open position and protect these
components in the closed position.
[0028] In an embodiment, the system may also be modular in design.
The inventive sonar unit will send and receive signals and display
the results on a variety of output devices that are connected by a
wires or wireless communications. The output may be a display
(color or black and white) having a high resolution and good
contrast to show all the detail crisply and clearly. The sonar scan
may be displayed on a screen such as a liquid crystal display
(LCD). Increased resolution allows small targets like fish and
other fine detail to be accurately shown on the display. The screen
may illustrate all objects that are in the presence of the
transducer's cone angle. The user can look at the screen and
determine where the objects (fish) are in relation to the
individual as well as the size of the objects.
[0029] Alternatively, the display may be a simple light such as a
flashing light emitting diode (LED) which produces instantaneous
blips of light or an audible signal from a speaker or ear phone
which warns the user of a potential dangerous presence. In these
embodiments, the sonar device will include a filter which will only
transmit a warning signal if the reflected signal produced by the
detected object is sufficiently large to be a concern to the user.
In this embodiment, the signal reflected signal must be strong
enough to represent a large fish that can produce bodily harm. The
filter is required because the notification of the presence of any
small fish would only be a nuisance to the user. In an embodiment,
this filtering mechanism can be adjusted so that warning signal can
be tuned to a specific size of fish depending upon the application.
For example, windsurfers and surfers are only concerned about large
fish but scuba divers may be very interested in detecting specific
types of small fish.
[0030] In yet another embodiment, the system may be configured to
emit a shark repellant solution or actuate an electronic shark
repellant electrical field when a shark is detected in the area.
The shark repellant solution may be housed in a container which has
an electronically controlled valve which allows the repellant to be
released into the water. When a shark is detected, the
microprocessor may actuate the valve to release the repellant. The
container may be pressurized or have a supplemental gas pressure
chamber so that when the valve is actuated, the repellant is forced
into the surrounding waters immediately.
[0031] In order to be easily handled underwater the portable sonar
device should have a buoyancy that is similar to that of the
surrounding water. By matching the density of the portable sonar to
that of the water, the device will not rise or fall. The density of
water is 1,000 Kilograms per cubic meter and the density of salt
water is 1,027 kilograms per cubic meter. In order to produce a
device that has similar buoyancy the inventive portable sonar
device should have a weight to volume ratio that is about 1,000
kg/cubic meter. In order to avoid loosing the device if it is
dropped, the buoyancy should be slightly less than 1,027 kilograms
per cubic meter so that the device will float in pure water.
[0032] In yet another embodiment, a plurality of the inventive
shark detection device can be set up in fixed positions to surround
a specific area of water, for example a swimming beach area. When a
shark is detected, the warning signals are transmitted to a central
receiver which emits a warning signal to alert the people in the
area that a shark has been detected. The warning signal can be an
audible or visual signal. Communications between the detectors and
the receiver can be through a wire, optical fiber, wireless
communication or any other suitable means of communications.
Because sea water strongly absorbs electromagnetic radio wave
communications with submerged detectors are limited to just a few
hertz. Alternatively, the detectors may float at the surface with
solar panels and radio antenna exposed to the air and the sonar
transmitter and receiver submerged below the surface of the water.
These components may be integrated into a single unit or configured
in separate units. With the antenna exposed, the can device can
emit normal radio frequency signals. By tuning the detection to
specific types of hazardous sharks, the public beaches can be made
safer without resorting to nets which can trap sea life.
[0033] While the invention has been shown or described in only some
of its forms, it should be apparent to those skilled in the art
that it is not so limited, but is susceptible to various changes
without departing from the scope of the invention. For example, the
dampening materials may be formed from a thin film, sheet, molded
or a combination thereof, and may be placed at a variety of
interfaces to further reduce vibration and shock.
* * * * *