U.S. patent application number 14/887109 was filed with the patent office on 2016-02-11 for systems and methods for tracking diver location.
This patent application is currently assigned to Pelagic Pressure Systems Corp.. The applicant listed for this patent is Pelagic Pressure Systems Corp.. Invention is credited to Robert R. Hollis, John E. Lewis.
Application Number | 20160041269 14/887109 |
Document ID | / |
Family ID | 30115796 |
Filed Date | 2016-02-11 |
United States Patent
Application |
20160041269 |
Kind Code |
A1 |
Lewis; John E. ; et
al. |
February 11, 2016 |
Systems and Methods for Tracking Diver Location
Abstract
Systems and methods for tracking diver location in accordance
with embodiments of the invention are disclosed. In one embodiment,
a dive computer includes a processor, a pressure transducer
connected to the processor, and clock circuitry connected to the
processor, wherein the processor obtains water speed information
using a flow measurement device that measures water speed when
below water, measures a first piece of position information using a
global position system receiver (GPS) that generates position
information, generates depth and time information using the
pressure transducer and the clock circuitry when the dive computer
is below water, combines the first piece of position information,
depth information, water speed information, and time information
into a dive log, stores the dive log using a memory, and estimates
a position of a diver using the first piece of position
information, time, depth, and water speed information from the dive
log when submerged.
Inventors: |
Lewis; John E.; (Rancho
Palos Verdes, CA) ; Hollis; Robert R.; (San Leandro,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Pelagic Pressure Systems Corp. |
San Leandro |
CA |
US |
|
|
Assignee: |
Pelagic Pressure Systems
Corp.
|
Family ID: |
30115796 |
Appl. No.: |
14/887109 |
Filed: |
October 19, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12170871 |
Jul 10, 2008 |
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14887109 |
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11264290 |
Oct 31, 2005 |
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12170871 |
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10615635 |
Jul 8, 2003 |
6972715 |
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11264290 |
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60394982 |
Jul 8, 2002 |
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Current U.S.
Class: |
342/357.52 |
Current CPC
Class: |
B63C 2011/021 20130101;
G01S 19/13 20130101; G01S 19/35 20130101; G01S 19/51 20130101; G06F
1/163 20130101; G01S 19/45 20130101; G01S 19/14 20130101; B63C
11/26 20130101; G01S 19/36 20130101; G01S 19/19 20130101 |
International
Class: |
G01S 19/51 20060101
G01S019/51; G01S 19/45 20060101 G01S019/45; G01S 19/13 20060101
G01S019/13; B63C 11/26 20060101 B63C011/26; G06F 1/16 20060101
G06F001/16 |
Claims
1. A dive computer, comprising: a processor; a pressure transducer
connected to the processor; and clock circuitry connected to the
processor; wherein the processor: obtains water speed information
using a flow measurement device that measures water speed when
below water; measures a first piece of position information using a
global position system receiver (GPS) that generates position
information; generates depth and time information using the
pressure transducer and the clock circuitry when the dive computer
is below water; combines the first piece of position information,
depth information, water speed information, and time information
into a dive log; stores the dive log using a memory; and estimates
a position of a diver using the first piece of position
information, time, depth, and water speed information from the dive
log when the dive computer is submerged.
2. The dive computer of claim 1, wherein the dive computer further
comprises the flow measurement device.
3. The dive computer of claim 1, wherein the flow measurement
device is located on the body of the diver and is connected to the
dive computer.
4. The dive computer of claim 3, wherein the flow measurement
device is connected to the dive computer using a wireless
connection.
5. The dive computer of claim 1, wherein the dive computer further
comprises the GPS receiver.
6. The dive computer of claim 1, wherein the GPS receiver is
located on the body of the diver and is connected to the dive
computer.
7. The dive computer of claim 1, wherein the GPS receiver obtains
the first piece of position information when the dive computer is
above water.
8. The dive computer of claim 1, wherein: the GPS receiver is
connected to a buoy above water; the buoy comprises an antenna; and
the GPS receiver obtains position information using the
antenna.
9. The dive computer of claim 8, wherein the GPS receiver obtains
position information when the dive computer is below water.
10. The dive computer of claim 1, wherein the processor calculates
the amount of time a diver can remain at a particular depth without
the need for decompression stops.
11. The dive computer of claim 1, wherein: the dive computer
further comprises a temperature sensor; and the processor
determines water temperature using the temperature sensor.
12. The dive computer of claim 1, wherein the processor calculates
when a diver can safely board an airplane based on the dive
log.
13. The dive computer of claim 1, wherein: the memory comprises a
plurality of memory units; and at least one of the plurality of
memory units is removable from the dive computer.
14. The dive computer of claim 1 wherein: the processor measures a
second piece of position information using the GPS receiver after
the dive computer is above water after being below water; and the
processor estimates a position of a diver using the combined time,
depth, and position information from the dive log using the second
piece of position information.
15. The dive computer of claim 14, wherein the second piece of
position information is included in the dive log.
16. The dive computer of claim 1, wherein the processor further:
determines a straight line distance between the start point of the
dive and the position of the diver; and calculates a speed of the
dive computer based on the time information in the dive log and the
determined straight line distance.
17. The dive computer of claim 1, wherein the flow measurement
device is connected to an air tank.
18. The dive computer of claim 1, wherein: the dive computer
further comprises a compass that determines the direction that the
compass is moving; and the processor obtains direction information
from the compass.
19. The dive computer of claim 18, wherein the processor combines
the direction information into the dive log.
20. The dive computer of claim 1, wherein the dive computer can be
worn on the wrist of the diver.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 12/170,871, filed Jul. 10, 2008, which is a
divisional of U.S. patent application Ser. No. 11/264,290, filed
Oct. 31, 2005 and now abandoned, which is a continuation
application of U.S. patent application Ser. No. 10/615,635, filed
Jul. 8, 2003 and now U.S. Pat. No. 6,972,715, which claims priority
of U.S. Provisional Application No. 60/394,982, filed Jul. 8, 2002,
the disclosures of which are hereby incorporated by reference in
their entirety.
FIELD OF INVENTION
[0002] The present invention relates generally to underwater
exploration and more specifically to apparatus and techniques for
determining location during a dive.
BACKGROUND OF THE INVENTION
[0003] The development of self-contained breathing systems has
enabled humans to dive and remain underwater for several hours. The
ability to remain underwater for an extended period of time can
enable divers to reach considerable depths and cover expansive
distances in exploring underwater terrain.
[0004] A problem commonly encountered by divers is an inability to
accurately locate position underwater. Position is typically
expressed in terms of three co-ordinates. The position of a diver
underwater can be expressed in terms of a latitude, a longitude and
a depth co-ordinate. The latitude and the longitude co-ordinates
represent the latitude and the longitude of a point on the surface
of the water directly above the diver. The depth co-ordinate
represents the depth of the diver below the surface of the water. A
dive computer similar to a ProPlus 2 manufactured by Oceanic
Worldwide of San Leandro, Calif. can be used to track depth during
a dive. However, depth alone is insufficient to locate the position
of a diver during a dive.
SUMMARY OF THE INVENTION
[0005] Systems and methods for tracking diver location in
accordance with embodiments of the invention are disclosed. In one
embodiment, a dive computer includes a processor, a pressure
transducer connected to the processor, and clock circuitry
connected to the processor, wherein the processor obtains water
speed information using a flow measurement device that measures
water speed when below water, measures a first piece of position
information using a global position system receiver (GPS) that
generates position information, generates depth and time
information using the pressure transducer and the clock circuitry
when the dive computer is below water, combines the first piece of
position information, depth information, water speed information,
and time information into a dive log, stores the dive log using a
memory, and estimates a position of a diver using the first piece
of position information, time, depth, and water speed information
from the dive log when the dive computer is submerged.
[0006] In another embodiment of the invention, the dive computer
further includes the flow measurement device.
[0007] In additional embodiment of the invention, the flow
measurement device is located on the body of the diver and is
connected to the dive computer.
[0008] In yet another additional embodiment of the invention, the
flow measurement device is connected to the dive computer using a
wireless connection.
[0009] In still another additional embodiment of the invention the
dive computer further includes the GPS receiver.
[0010] In yet still another additional embodiment of the invention,
the GPS receiver is located on the body of the diver and is
connected to the dive computer.
[0011] In yet another embodiment of the invention the GPS receiver
obtains the first piece of position information when the dive
computer is above water.
[0012] In still another embodiment of the invention, the GPS
receiver is connected to a buoy above water, the buoy includes an
antenna, and the GPS receiver obtains position information using
the antenna.
[0013] In yet still another embodiment of the invention the GPS
receiver obtains position information when the dive computer is
below water.
[0014] In yet another additional embodiment of the invention the
processor calculates the amount of time a diver can remain at a
particular depth without the need for decompression stops.
[0015] In still another additional embodiment of the invention, the
dive computer further includes a temperature sensor and the
processor determines water temperature using the temperature
sensor.
[0016] In yet still another additional embodiment of the invention,
the processor calculates when a diver can safely board an airplane
based on the dive log.
[0017] In yet another embodiment of the invention, the memory
includes a plurality of memory units and at least one of the
plurality of memory units is removable from the dive computer.
[0018] In still another embodiment of the invention, the processor
measures a second piece of position information using the GPS
receiver after the dive computer is above water after being below
water and the processor estimates a position of a diver using the
combined time, depth, and position information from the dive log
using the second piece of position information.
[0019] In yet still another embodiment of the invention, the second
piece of position information is included in the dive log.
[0020] In yet another additional embodiment of the invention, the
processor further determines a straight line distance between the
start point of the dive and the position of the diver and
calculates a speed of the dive computer based on the time
information in the dive log and the determined straight line
distance.
[0021] In still another additional embodiment of the invention, the
flow measurement device is connected to an air tank.
[0022] In yet still another additional embodiment of the invention,
the dive computer further includes a compass that determines the
direction that the compass is moving and the processor obtains
direction information from the compass.
[0023] In yet another embodiment of the invention, the processor
combines the direction information into the dive log.
[0024] In still another embodiment of the invention, the dive
computer can be worn on the wrist of the diver.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a schematic illustration of an embodiment of a
dive computer in accordance with practice of the present
invention;
[0026] FIG. 2 is a flow chart illustrating a method of recording
latitude, longitude, depth and time during a dive in accordance
with practice of the present invention;
[0027] FIG. 3 is a flow chart illustrating a method of locating a
point of interest using data recorded in accordance with practice
of the present invention;
[0028] FIG. 4 is a schematic illustration of a dive computer
including a buoy having a GPS receiver antenna that is connected to
the dive computer via a spool of communication cable;
[0029] FIG. 5 is a side view of a submerged diver equipped with a
dive computer in accordance with the present invention including a
buoy that is deployed at the surface;
[0030] FIG. 6 is a flow chart illustrating a method of recording
latitude, longitude, depth and time during a dive in accordance
with practice of the present invention that ensures that an
automatic measurement of latitude, longitude and time is made as a
dive is commenced;
[0031] FIG. 7 is a flow chart illustrating a method of recording
locations that a diver considers important;
[0032] FIG. 8 is a flow chart illustrating a method of detecting
speech commands in accordance with practice of the present
invention;
[0033] FIG. 9 is a schematic illustration of an embodiment of a
dive computer in accordance with practice of the present invention
that includes an impeller and a compass;
[0034] FIG. 10A is a side view of a diver equipped with an air tank
including a regulator and using a dive computer that includes an
impeller and a compass mounted on the first stage of the regulator
in accordance with practice of the present invention;
[0035] FIG. 10B is a side view of diver using a dive computer that
includes an impeller and a compass that is hose mounted;
[0036] FIG. 10C is a side view of diver using a dive computer that
includes an impeller and a compass that is wrist mountable;
[0037] FIG. 11 is a flow chart illustrating a method of recording
latitude, longitude, depth, time, bearing and water speed during a
dive in accordance with practice of the present invention;
[0038] FIG. 11A is a flow chart illustrating a method of estimating
the course taken by a diver based on GPS measurements and water
speed, depth and bearing measurements recorded during the dive;
[0039] FIG. 12 is a schematic illustration of an embodiment of a
dive computer in accordance with practice of the present invention
that includes a pressure transducer for measuring air pressure in
an air tank; and
[0040] FIG. 13 is a flow chart illustrating a process for
estimating the range of a diver using information concerning air
time remaining and water speed.
DETAILED DESCRIPTION OF THE INVENTION
[0041] Referring now to the drawings, dive computers in accordance
with practice of the present invention are illustrated. The dive
computers make and record at least three significant sets of
measurements, which enable the estimation of the location of points
of interest underwater and the path traveled by a diver during a
dive. The first set of measurements typically includes measurements
of latitude, longitude and time immediately prior to the
commencement of a dive. The second set of measurements can be
generated by periodically measuring depth and time during a dive.
The third set of measurements can be compiled by measuring
latitude, longitude and time immediately upon resurfacing from a
dive. Following a dive, an estimation of location at a specified
time during the dive using these three sets of measurements can be
made by using a number of techniques in accordance with practice of
the present invention. In several embodiments, the accuracy of the
estimation can be increased by including measurements of speed and
bearing in the second set of measurements.
[0042] Turning now to FIG. 1, a dive computer in accordance with
practice of the present invention is illustrated. The dive computer
10 includes a processor 12 that is connected to memory 14, a global
positioning system (GPS) receiver 16, clock circuitry 18 and an
input/output interface 20. The input/output interface 20 is
connected to a number of devices that can be used to communicate
with a user or other devices. In one embodiment, these devices
include a pressure transducer 22, a keypad 24, a display 26, a
communications port 28 and a microphone 30. A digital camera 32 is
also provided as an input device, however, the digital camera
bypasses the microprocessor and is connected directly to the memory
14.
[0043] The processor 12 receives information from the GPS receiver
16, the clock circuitry 18 and the input/output interface 20 and
selectively stores the information in memory 14. In one embodiment,
the processor is implemented using a MSP430F149 manufactured by
Texas Instruments Incorporated of Dallas, Tex. However, the
processor could be implemented using discrete logic components or
several separate processing elements that share information.
[0044] The memory 14 can be used to store data logged by the dive
computer 10, to temporarily store information during the
performance of calculations and to store software used to control
the operation of the processor 12. The memory 14 need not be a
single integrated circuit and can be constructed from a number of
integrated circuits having distinct properties. In the illustrated
embodiment, the memory 14 includes non-volatile memory circuits 34
to store software for controlling the processor 12, manufacturer
settings, user settings and calibration data. In addition, the
memory 14 also includes a removable memory device 36 that is used
to store data logged during a dive such as images, a dive profile,
dive logs, GPS logs and/or audio recordings. One aspect of using a
removable memory device is that individual dives can be logged on
separate removable memory devices and the removable memory devices
used as a method of storing the logged data remote from the dive
computer. In embodiments that use a MSP430F149 processor or
equivalent processor device, the non-volatile memory included on
the processor chip can be used to implement the non-volatile memory
circuits 34 and the removable memory device can be implemented
using a SDMB-128-768 128 MB MultiMedia Card manufactured by SanDisk
of Sunnyvale, Calif. In other embodiments, memory devices of
various sizes, volatility and portability can be used depending on
the software requirements of the system and the data logging
requirements of the user. For example, the removable memory device
can be replaced by a similar sized fixed memory device such as an
AT2508N-1051-1.8 manufactured by Atmel Corporation of San Jose,
Calif. or an equivalent memory device.
[0045] The GPS receiver 16 utilizes signals broadcast from
satellites to make calculations of latitude and longitude. The GPS
receiver provides the latitude and longitude information to the
processor, which is responsible for the processing and storage of
the information. In one embodiment, the GPS receiver is implemented
using a GeoHelix-H GPS antenna manufactured by Sarantel Ltd. of
Wellingborough, United Kingdom. In other embodiments, other GPS
receiver technologies, such as an Embedded 3.3V GPS Antenna in
conjunction with an M-LocJ MPM module both manufactured by Trimble
Navigation Limited of Sunnyvale, Calif., can be used that are
capable of providing information to the processor that can be used
to generate latitude and longitude co-ordinates.
[0046] The clock circuitry 18 can be used to measure the passage of
time. Typically the clock circuitry 18 will incorporate a quartz
crystal that is used to generate a periodic signal that can be
observed in order to measure the passage of time. The clock
circuitry 18 can also be synchronized with an external clock to
enable time to be expressed in absolute terms using a time, a day,
a month and a year. In one embodiment the clock circuitry is part
of the MSP430F149 microcontroller described above. In other
embodiments, the absolute time can be obtained using the GPS
receiver 16.
[0047] The input/output interface 20 can be constructed from any
variety of wires, antennas, transmitters, receivers, connectors and
buffers. The configuration of the input/output interface 20 is
dependent on the input/output devices that are connected to the
dive computer. In the embodiment shown in FIG. 1, the input/output
devices include a pressure transducer, a keypad, a display, a
communications port and a microphone. In other embodiments, any
other combination of input/output devices can be connected to the
dive computer via the input/output interface. In one embodiment,
the portion of the input/output interface connected to the pressure
transducer includes a standard analog to digital converter. In
addition, the input/output interface uses a display driver such as
an S6B33A1 manufactured by Samsung of Seoul, South Korea to connect
to segment display 26 and a CS53L32A High Speed Analog to Digital
converter manufactured by Cirrus Logic, Inc. of Austin, Tex. to
connect to the microphone 30.
[0048] The pressure transducer 22 can be used to measure the
pressure of the water in which the dive computer is immersed. In
one embodiment a 17887.A Low Pressure Transducer manufactured by
Pelagic Pressure Systems of San Leandro, Calif. can be used to
construct the pressure transducer 22. In other embodiments, other
circuits capable of generating an electrical signal indicative of
the water pressure in which the dive computer is immersed can be
used.
[0049] A keypad 24 is typically provided to enable the user to
enter information concerning the dive or to direct the processor 12
to provide the user with information. In one embodiment, the keypad
24 includes one or more buttons that can be used to tag the
location of the user as a point of interest. As will be explained
in greater detail below, the tagged location can be subsequently
retrieved from the memory 14 of the dive computer 10. In other
embodiments, the keypad 24 can include one or more buttons,
toggles, joysticks or equivalent devices with which the user can
provide instructions to the processor 12.
[0050] A display 26 is typically provided to present information in
a graphical manner to the user. Information that can be provided to
the user includes a recent GPS reading, depth and/or time. If the
dive computer 10 performs other functions, information relating to
these functions can also be communicated using the display 26.
[0051] One skilled in the art will appreciate that the connection
of keypads 24 and displays 26 to dive computers 10 is well known
and any number of possible configurations, devices and circuitry
could be used to establish a connection between these devices and
the processor 12.
[0052] The communications port 28 is provided to enable the
transfer of information between the dive computer 10 and other
devices. In one embodiment, the communications port 28 is an
Integrated Low Profile Transceiver Module IrDA standard such as the
TFDU4100 manufactured by Vishay Semiconductor, Inc. of Malvern, Pa.
In other embodiments, other wired or wireless connections and
protocols can be used to communicate with external devices. The
transfer of information via the communications port 28 enables the
movement of data and new software between the dive computer 10 and
other devices. In one embodiment, dive information stored in the
dive computer memory 14 can be loaded onto a personal computer and
stored, graphed or manipulated. In addition, information from a
previous dive stored on an external device can be loaded into the
memory 14 of the dive computer for reference during a subsequent
dive or information stored within the dive computer can be
manipulated by external devices.
[0053] The microphone 30 is provided to enable the audio annotation
of data logged by the dive computer 10. The annotations can be made
before, during or after a dive by making a digital recording of the
words spoken by the user and associating them with a particular
dive or with particular tagged locations. In other embodiments,
automatic speech recognition could be used to generate textual
annotations. The addition of automatic speech recognition
technology would also enable the dive computer to respond to
audible instructions from the user. In one embodiment, the
microphone 30 can be a MAB-06A-B manufactured by Star Micronics
Company, Ltd. of Edison, N.J. As described above, the input/output
interface 20 can include an analog-to-digital converter for
connection to the microphone. The analog-to-digital converter can
sample the analog signal generated by the microphone 30 and
generate a digital representation of the analog signal. In one
embodiment, the analog-to-digital converter samples the signal from
the microphone 30 at a rate of 8 kHz and uses 28 quantization
levels to represent the signal. In other embodiments, other
sampling rates and a different number of quantization levels can be
used as is appropriate.
[0054] In embodiments where automatic speech recognition is used,
the processor 12 or a discrete device in the input/output interface
20 can convert the digital representations of the signals from the
microphone 30 to text or commands using hidden Markov models,
neural networks, hybrid neural network/hidden Markov models or
other speech modeling or recognition techniques. In one embodiment,
speech recognition is performed using a RSC-4x Speech Recognition
Microcontroller manufactured by Sensory, Inc. of Santa Clara,
Calif.
[0055] The digital camera 32 is provided to enable the capture of
images during a dive and to enable the use of these images as part
of a dive log if desired by the user. The digital camera can be
implemented using a lens and an array of charge coupled devices
both of which are contained within the waterproof dive computer
housing. In one embodiment, the digital camera is implemented using
a MB86S02A CMOS sensor manufactured by Fujitsu Microelectronics
America, Inc. of Sunnyvale, Calif. to capture image information and
a MCF5307 Direct Memory Access Controller manufactured by Motorola,
Inc. of Schaumburg, Ill. to transfer the image information directly
to the memory 14. In other embodiments, any circuitry capable of
capturing a digital image can be used to obtain image information
and store it in memory either via direct memory access or using the
processor 12 in combination with the input/output interface 22.
[0056] Other input or output devices in addition to those described
above can be connected to a dive computer in accordance with the
present invention. In one embodiment speakers are connected to the
input/output interface to enable the playback of recorded speech or
to allow a diver to listen to music during a dive. In other
embodiments, other combinations of devices can be used to meet the
information requirements and data recording requirements of a diver
during a dive.
[0057] Turning now to FIG. 2, a method 40 of recording information
during a dive that enables estimation of position in accordance
with practice of the present invention is illustrated. The method
includes taking (42) a first GPS measurement, which is performed
prior to descending (44) below the surface. Once below the surface,
depth and time are periodically measured (46). After ascending (48)
to the surface, a second GPS measurement is taken (50).
[0058] If data is logged during a dive in accordance with the
method 40, then position during the dive can be estimated. If the
user tags a particular location during a dive as being of interest,
then the user can use the data logged in accordance with the method
40 shown in FIG. 2 to subsequently locate the point of
interest.
[0059] Turning now to FIG. 3, a method of locating a previously
identified point of interest using data logged in accordance with
practice of the present invention is illustrated. The method 60
includes calculating (62) the duration of the recorded dive,
calculating (64) the time that was taken to reach the identified
point of interest from the start point of the dive and determining
(66) a straight line `L` between the start point of the dive and
the end point of the dive. Once these functions have been
performed, a value `A` is then calculated (68), which is equal to
the length of the line `L` multiplied by the time taken to reach
the point of interest and divided by the duration of the dive. The
value `A` is then used to locate (70) a point `P` that is a
distance `A` from the start point of the dive along the line
`L`.
[0060] Once the point `P` has been identified, a diver can travel
(72) to the latitude and longitude of point `P` and commence a
dive. The diver can then enter the water and descend (74) to the
recorded depth of the point of interest. At this depth, the point
of interest can be located by searching (76) outwardly while
attempting to maintain the recorded depth of the point of interest.
The depth of a point of interest is particularly important in
relocating that point. The co-ordinates calculated as the latitude
and longitude of a point of interest using data collected by a dive
computer in accordance with the practice of the present invention
are simply estimates that place a diver in the vicinity of the
point of interest. The knowledge of the depth at which the point of
interest is located enables the diver to perform an expanding
search in the plane of that depth. Without this information, a
diver could be forced to search in three dimensions instead of two.
The advantages of knowing a depth co-ordinate are increased when
the point of interest forms part of the topography of the sea
floor. A diver can rapidly locate such a point of interest by
simply descending to the recorded depth of the point of interest
and then searching outwardly from the point of descent until a
portion of the sea bed is encountered at the recorded depth of the
point of interest. By following the topography of the sea bed at
the depth of the point of interest, the diver has a high likelihood
of rapidly relocating the point of interest.
[0061] The method 60 illustrated in FIG. 3 can use data recorded in
accordance with the method 40 shown in FIG. 2. The time recorded at
the beginning of the dive and the time recorded at the end of the
dive can be used to calculate (62) the duration of the dive.
Likewise, the time at the beginning of the dive and the time
recorded at the point of interest can be used to calculate (64) the
time taken to reach the point of interest. The latitude and
longitude co-ordinates at the beginning of the dive and the
latitude and longitude co-ordinates at the end of the dive can be
used to generate the line `L` (68) and the times calculated above
can be used to locate the estimated latitude and longitude of the
point of interest as described above.
[0062] Other techniques can be used to locate a point of interest
using data recorded in accordance with practice of the present
invention. In one embodiment, the logged data can be used to return
to a point of interest by commencing the second dive at the
latitude and longitude of whichever of the start and end points of
the earlier dive was closest to the point of interest. The diver
can then travel towards the other of the start and end points. The
point of interest can then be located by traveling in this
direction at the recorded depth of the point of interest for a time
approximating the time it took to travel to the point of interest
during the previous dive.
[0063] If a diver seeks to be able to return to a point of interest
with a high degree of accuracy on subsequent dives, then the diver
is advised to ascend to the surface at the point of interest. The
dive computer 10 can then make a GPS measurement and the diver can
be confident that returning to the recorded latitude and longitude
and descending to the recorded depth will enable rapid location of
the point of interest.
[0064] An alternative to ascending to the surface is to use the
dive computer 10' illustrated in FIG. 4 that includes a compass 70
and a GPS antenna 72 mounted on a buoy 74, which is connected to
the other components of the dive computer 75 via a spool 76 of
communication cable 78. In other embodiments, a wireless connection
is used between the spool and the other components of the dive
computer. When a diver wishes to take a measurement of latitude and
longitude at a point of interest, the buoy is released. At the
surface, the antenna can receive the satellite signals required to
measure latitude and longitude. These signals are then conveyed to
the GPS receiver via the communications cable. In other
embodiments, additional components such as the entire GPS receiver
can be included in the buoy. In one embodiment the spool is an
AR-05 manufactured by Saekodive of Taiwan.
[0065] Displacement of the buoy relative to the position of the
diver is illustrated in FIG. 5. The displacement of the buoy 74
relative to a position "P" directly above the diver can be
calculated using Pythagoras' theorem by measuring the length of
communication cable 78 released from the spool 76 and the depth of
the diver. The length of communication cable released can be
measured using markings on the cable 78 and entered in the dive
computer manually or via voice command. Alternatively an external
line counter could be used that communicates to the processor of
the dive computer via a wireless or wired link. The depth of the
diver can be measured using the dive computer in the manner
described above. The direction of the displacement can be
determined using a compass bearing of the cable relative to the
diver.
[0066] Embodiments of the dive computer in accordance with practice
of the present invention can enable automatic recording of latitude
and longitude immediately prior to the dive computer 10 descending
below the surface of the water and immediately upon returning to
the surface. Turning now to FIG. 6, a method in accordance with
practice of the present invention for automatically recording the
latitude, longitude and time prior to commencing a dive and upon
surfacing from a dive is illustrated. The method 90 includes making
(92) and storing (94) measurements of latitude, longitude and time
using a GPS receiver. The process of measuring latitude, longitude
and time with the GPS receiver and storing the values continues
until the diver descends below the surface and the answer to the
decision (96) of whether the diver has descended below the surface
becomes affirmative.
[0067] Once the diver is below the surface, measurements (98) of
depth and time are made and the measurements are recorded (100) in
the memory of the dive computer. The measurement and recording of
depth and time continues for as long as the diver remains below the
surface and until the answer to the decision (102) of whether the
diver has surfaced is affirmative. Once the diver has surfaced, a
measurement (104) of latitude, longitude and time is made and the
measurement is recorded.
[0068] The method 90 described in FIG. 6 can ensure that the
measurement stored at the commencement of the dive is the most
recent measurement of latitude, longitude and time that has been
made by the GPS receiver 16 and dive computer 10. In addition, the
method 90 enables periodic measurement of depth and time during the
dive and the rapid recording of latitude, longitude and time when
the diver resurfaces. In other embodiments, the logging of
latitude, longitude and time can be initiated in response to user
input.
[0069] The method 90 shown in FIG. 6 can be modified to enable the
diver to identify points of interest during the dive. Turning now
to FIG. 7, a method in accordance with the practice of the present
invention of identifying points of interest during a dive is
illustrated. The method 110 is performed while the diver is under
water. The method 110 can commence with the measurement (112) of
depth and time. Once a measurement of depth and time has been made,
the measurements are recorded (114). Prior to making another
measurement of depth and time, a check is made (116) for any user
input. If user input is detected, then the previous or next depth
and time measurements are identified (118) as a point of
interest.
[0070] In addition to identifying points of interest, it is
desirable to be able to associate information with a point of
interest. One advantageous method of providing inputs to a dive
computer 10 is through the use of a microphone, as is described
above. Speech commands can be used to control the function of the
dive computer and speech can be either recorded or converted to
text in order to provide description or annotation to a point of
interest. In embodiments where speech can be recorded, the
recording of speech can be initiated by the pressing of a button on
the keypad 24 or by a voice command recognizable by the dive
computer. In one embodiment, the microphone is contained within a
full face mask enabling speech to be recorded underwater. In other
embodiments, more than one microphone is included so that a diver
may record speech using a first microphone and underwater sounds or
environmental noise using a second microphone. In embodiments of
the dive computer 10 that include a digital camera 32, one or more
still images or a series of still images forming a video sequence
can be recorded and associated with a point of interest.
[0071] Turning now to FIG. 8, a method in accordance with practice
of the present invention is illustrated for responding to voice
commands. The method 130 includes listening (132) for sound. Once
sound is detected, a decision (134) is performed to determine if a
"voice spotting" sound has been detected. A "voice spotting" sound
is a spoken word such as "computer" that can indicate that a user
is preparing to speak a command to a dive computer 10.
[0072] If the "voice spotting" sound is detected, then the method
involves listening (136) for a command. A dive computer 10 in
accordance with practice of the present invention will typically
have a library of commands each requiring different responses from
the processor 12. If a sound is heard, then a decision (138) is
performed to determine whether the sound corresponds to one of the
commands recognized by the dive computer 10. If a command is
recognized, then a response is made (140) to the command. Once the
response is complete, the process 130 returns to listening (132)
for sound to await the next command.
[0073] The method 130 described above uses a "voice spotting"
technique. In other embodiments, "voice spotting" is not required.
The speech recognition performed in "voice spotting" and detecting
commands can be either discrete or continuous recognition. The
speech recognition can also be either speaker dependent or speaker
independent. In embodiments where annotation of points of interest
can be performed, a speech command can cause the processor to begin
digitally recording speech and to associate the recording with a
particular point of interest. In other embodiments, other forms of
user input can be used to identify a point of interest and to
commence the digital recording of speech. Alternatively, a command
can cause the processor to convert a passage of speech to text
using speech recognition techniques and to associate the text with
a point of interest that can be identified using speech commands or
using an alternative user input technique.
[0074] As was observed above, latitude, longitude and time
measurements made in accordance with practice of the present
invention can be used to estimate the latitude and longitude of a
point of interest. The accuracy of this estimate can be effected by
currents and the variation in the speed at which the diver traveled
during the dive. The accuracy of the estimated latitude and
longitude of a point of interest can be improved in accordance with
the practice of the present invention by taking measurements of
water speed and bearing as is discussed below.
[0075] A dive computer 10'' in accordance with the practice of the
present invention including an impeller and a compass is
illustrated in FIG. 9. The dive computer 10'' is similar to the
dive computer 10 illustrated in FIG. 1, but with the addition that
an impeller 150 and a compass 152 are connected to the processor
via the input/output interface. Impellers are devices that generate
signals that can be used to measure the flow rate of a liquid or
the water speed of the dive computer. By attaching an impeller
equipped dive computer to a diver, the output of the impeller can
be used to measure the speed at which the diver is moving through
water and the compass can be used to provide signals to the
processor indicative of the direction in which the diver is moving.
In one embodiment, a 3000 impeller manufactured by
Nielsen-Kellerman of Chester, Pa., in conjunction with a receiver
coil connected to a counter that can be used to implement the
impeller and a HMC 1055 3-axis magnetic sensor manufactured by
Honeywell International of Morristown, N.J., that can be used to
implement the compass. In other embodiments other types of flow
measurement devices can be used to measure water speed.
[0076] A diver equipped with a dive computer in accordance with the
present invention is illustrated in FIG. 10A. The dive computer 160
is implemented as two discrete components 162 and 164. The first
component 162 is worn around the wrist of the diver and includes
all of the components of the dive computer 10'' illustrated in FIG.
10A except for the impeller and the compass. The impeller and the
compass are located in a second component 164 that is fixed to an
air tank worn 166 by the diver. In the illustrated embodiment, the
two components communicate via a wireless communications link.
[0077] Typically, a diver is fully extended while swimming and
fixing the impeller in a direction parallel to the long axis 168 of
the diver as the diver swims provides an accurate measurement of
the speed of the diver. In addition, mounting the compass so that
the bearing measurement is made along a line parallel to the long
axis of the diver also enables an accurate measurement of bearing
to be made. In order to ensure that both the impeller and compass
are accurately aligned, it is desirable that the impeller and the
compass be fixed to maintain a position relative to the body of the
diver throughout the dive. Therefore, in the embodiment illustrated
in FIG. 10A the impeller and the compass are fixed to the air tank
166 and aligned to be approximately parallel to the long axis 168
of the body of the diver, when the diver is fully extended. In
other embodiments, the impeller and the compass can be fixed to
other locations on the body or equipment of a diver. In other
embodiments, the compass and impeller are included in a single unit
with the other components of the dive computer and the position of
the impeller and the compass can be controlled by the diver. A
diver can use such a dive computer in accordance with the present
invention to take instantaneous current readings, to use
instantaneous speed calculations to calculate range based on air
time remaining (see discussion below) or for any other application
where an instantaneous measurement of speed can be useful. An
example of a hose mounted dive computer 10'' including an impeller
and a compass is illustrated in FIG. 10B and an example of wrist
mountable dive computer 10'' including an impeller and a compass is
illustrated in FIG. 10C.
[0078] A method of recording data in accordance with practice of
the present invention is shown in FIG. 11. The method 40' is
similar to the method 40 illustrated in FIG. 2, with the difference
that the periodic measurements of depth and time are supplemented
with periodic measurements of bearing and water speed.
[0079] Assuming there is insignificant current, the measurements
obtained using the process illustrated in FIG. 11 provides a
complete map of the course taken by a diver. The starting latitude
and longitude locations provide the origin of the course and the
path followed by the diver can be determined using the water speed,
bearing, depth, and/or time information. Factors such as drift
current can be accounted for by scaling the course to ensure that
it terminates at the location where the diver surfaced, as measured
using the GPS receiver. This scaling can be performed by the dive
computer or by an external device that manipulates data provided by
the dive computer.
[0080] In one embodiment, the process illustrated in FIG. 11A is
used to adjust or scale the course obtained using recorded water
speed and bearing measurements in response to the latitude and
longitude measurements obtained at the origin and termination of a
dive. The process 170 includes defining (172) a planar co-ordinate
system at the origin of the dive using the co-ordinates x, y and z,
where z represents the depth dimension. Calculating (174) position
co-ordinates relative to the origin of the path taken during the
dive using the water speed, depth and bearing data. Determining
(176) position co-ordinates of the termination point of the dive
based on the water speed, depth and bearing data. Determining (178)
position co-ordinates of the termination point of the dive based on
the GPS receiver measurements of latitude and longitude.
Calculating (180) the scaling factors that the x and y co-ordinates
of the termination point determined using the water speed, depth
and bearing data must be multiplied by in order to obtain the x and
y co-ordinates of the termination point determined using the GPS
receiver measurements of latitude and longitude. An estimate of the
path taken during the dive is then obtained (182) by scaling the x
and y co-ordinates of the points in the path determined using the
recorded water speed, depth and bearing measurements by the
calculated scaling factors. The estimated path can then be output
(184) in terms of latitude, longitude and depth by mapping the
co-ordinates of the path from the planar co-ordinate system that
was defined relative to the origin of the dive to latitude,
longitude and depth co-ordinates.
[0081] An embodiment of a dive computer in accordance with the
present invention that incorporates pressure transducers in order
to measure air time remaining is illustrated in FIG. 12. The dive
computer 10'' includes a pressure transducer 200 that measures air
pressure inside an air tank. In one embodiment, the pressure
transducer 200 is implemented using a high pressure sensor such as
an 18519.A manufactured by Pelagic Pressure Systems of San Leandro,
Calif. Air pressure measurements can be converted into air time
remaining statistics in accordance with the methods described in
U.S. Pat. No. 4,586,136 to Lewis and U.S. Pat. No. 6,543,444 to
Lewis, both of which are incorporated herein by reference in its
entirety.
[0082] Knowledge of the water speed of the diver and the change in
air time remaining can be used to generate useful information for a
diver such as an estimation of the range that a diver can travel
with the air remaining in the tanks of the diver. A process for
calculating an estimation of range based on the air available to a
diver is illustrated in FIG. 13. The process 220 includes recording
speed over a predetermined period of time (222) and then
calculating the average speed during that period of time (224).
Once the average speed has been calculated, the air time remaining
is calculated (226). The air time remaining calculation can be used
in combination with the average speed calculation to predict the
range of the diver at current exertion levels. In other
embodiments, the air time remaining can be adjusted to reserve
sufficient air to allow the diver to return to the surface from the
depth at which the diver is located without significant risk of
decompression sickness.
[0083] Although the foregoing embodiments are disclosed as typical,
it will be understood that additional variations, substitutions and
modifications can be made to the system, as disclosed, without
departing from the scope of the invention. Thus the present
invention has been described by way of illustration and not
limitation. For example, embodiments of the invention can have GPS
receivers adapted to be submerged in water that are not connected
to the processor. These embodiments log latitude, longitude and
time information using the GPS receiver and separately log depth
and time information using a dive computer. The latitude, longitude
and time information from the GPS receiver and the depth and time
information from the dive computer can be downloaded to the dive
computer or another computer and the methods described above can be
used to determine position. In addition, dive computers in
accordance with the present invention can perform functions
performed by conventional dive computers such as providing divers
with information concerning decompression limits or the amount of
air remaining in a tank, however, it is not a limitation of the
invention that the dive computer perform these functions or other
functions typically associated with conventional dive computers.
Other functions can also be performed by the dive computer that are
not traditionally associated with dive computers such as functions
normally attributed to personal digital assistants (P.D.A.s) or
other more powerful computing devices. In addition, dive computers
in accordance with the present invention may consist of a
conventional dive computer and a microphone and/or a digital camera
and do not require the inclusion of a GPS receiver. Other
embodiments of dive computers in accordance with the present
invention may also combine several of the features described above
such as a buoy including a GPS antenna, a compass and an impeller.
It is therefore to be understood that the present invention can be
practiced otherwise than specifically described without departing
from the scope and spirit of the present invention. Thus,
embodiments of the present invention should be considered in all
respects as illustrative and not restrictive. Accordingly, the
scope of the invention should be determined not by the embodiments
illustrated, but by the appended claims and their equivalents.
* * * * *