JP2004245779A - System for determining position of submerging vessel and sonobuoy - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure in real time the position of a vessel cruising underwater such as a moving object which cruises underwater under the sea, without disposing a sensor on the bottom of the sea. <P>SOLUTION: An underwater cruising vessel 1 is equipped with a pinger 10 for emitting into the water an acoustic signal including information expressing the transmission time, in which the clock is set correct before the underwater cruising vessel 1 submerges. In the sea area for the operation, a plurality of sonobuoys 2 for receiving the acoustic signals from the pingers 10 and for measuring their own positions and the current time by a satellite positioning system such as GPS (Global Positioning System) satellites 5 are disposed. The position of the underwater cruising vessel 1 is calculated in real time, on the basis of the propagation time of the acoustic signal from the pinger 10 to the sonobuoy 2 received by each of the three or more sonobuoys 2 and the position of the sonobuoy 2. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a position determination system capable of measuring and tracking the position of an object (underwater vehicle) moving or navigating underwater in real time, and a sonobuoy used in such a position determination system.
[0002]
[Prior art]
For example, in order to measure the position of a self-propelled underwater vehicle in water, such as a self-propelled underwater vehicle for ocean research, in real time, or to track the underwater vehicle, many acoustic sensors have conventionally been installed on the sea floor over a wide sea area. The acoustic signals from the pinger mounted on the underwater vehicle are received by these acoustic sensors, and the position of the underwater vehicle is measured from the arrival time difference and the installation position of the acoustic sensor. Alternatively, a plurality of transponders are arranged on the sea floor, a responder is provided on the underwater vehicle, an acoustic response signal emitted by the responder is received by the transponder in response to the acoustic interrogation signal from the transponder, and the acoustic interrogation signal is transmitted. The position of the underwater vehicle is calculated from the time until the response signal is received and the laying position of each transponder. To obtain the current position on the underwater vehicle, a transponder is installed on the underwater vehicle, multiple responders are laid on the sea floor, and the responder responds to the acoustic interrogation signal emitted from the underwater vehicle. The emitted acoustic response signal is received by the underwater vehicle, and the position of the underwater vehicle is calculated based on the time difference between the acoustic response signals from each responder and the position of the responder.
[0003]
In any case, in the conventional position determination system, a plurality of sensors, transponders, responders, and the like are arranged on the water bottom of a test water area (such as an underwater vehicle) in such a manner that the respective laying positions can be accurately determined. In some cases, it is necessary to lay cables for transmitting and receiving power and signals to and from these sensors and transponders on the bottom of the water. For example, Patent Literatures 1 to 5 describe a position determination system in which a sensor, a transponder, and the like are arranged on a water bottom.
[0004]
In the present specification, terms such as underwater, water bottom, and water area are used without distinction between lakes, marshes, rivers, and the like and the ocean. Therefore, the underwater and the water bottom include the underwater, the seabed, and the sea area, respectively.
[0005]
[Patent Document 1]
JP-A-2002-257921
[Patent Document 2]
JP-A-8-136650
[Patent Document 3]
JP-A-6-118172
[Patent Document 4]
JP-A-5-302975
[Patent Document 5]
JP-A-5-302974
[0006]
[Problems to be solved by the invention]
However, in the above-described conventional position determination system, a large number of sensors, transponders, and the like are laid on the bottom of the vast test water so that their exact positions are clear, and in some cases, cables for connecting these are also laid. Therefore, there is a problem that it takes time and cost for installation. In addition, there are also problems that the installation location is restricted, such as difficulty in installation depending on the water bottom topography, and difficulty in coordinating with existing rights such as fishing rights.
[0007]
Accordingly, an object of the present invention is to provide a position determination system that can accurately measure and track the position of an underwater vehicle in real time without the need to lay a sensor or a transponder on the bottom of the water, and a position determination system such as this. Sonobuoy will be used.
[0008]
[Means for Solving the Problems]
The position determination system of the present invention is a position determination system that determines the position of the underwater vehicle, a sound emitting means that is mounted on the underwater vehicle and emits an acoustic signal into the water, and a plurality of sound generators are provided in the operating water area, A sonobuoy that receives an acoustic signal from the sounding body and measures its own position by a satellite positioning system, and a position of the underwater vehicle based on the reception timing of the acoustic signals at three or more sonobuoys and the position of the sonobuoy. And position calculation means for calculating
[0009]
In the present invention, the sounding means provided on the underwater vehicle includes, for example, a pinger that emits an acoustic signal including information indicating a transmission time underwater, or a response request signal (first acoustic signal) from a sound source buoy. A responder or the like that emits a response signal (second acoustic signal) into the water in response to the above may be used. In the case of using a pinger, the clock of the pinger is adjusted prior to the underwater traveling of the underwater vehicle, and the position calculation means receives the sound signal received from each of the three or more sonobuoys from the sonobuoy. The position of the underwater vehicle is calculated based on the propagation time (or propagation distance) up to and the position of the sonobuoy. When a responder is used, a sound source buoy that emits the first acoustic signal into the water and measures its own position by the satellite positioning system is further provided in the operating water area, and the position calculation means includes three or more sonobuoys. The position of the underwater vehicle is calculated based on the reception timing of the second acoustic signal received in the above, the position of the sonobuoy, and the position of the acoustic buoy. In order to secure the three-dimensional position limitation, it is preferable to use a sonobuoy having a plurality of receivers corresponding to different depths.
[0010]
In the present invention, for example, a global positioning system (GPS) is used as a satellite positioning system. If a pinger is used, the time information from the GPS may be used to set the time of the pinger. Preferably, the sonobuoy and the position calculating means are connected by a wireless line. In this case, the computer system that generally configures the position calculation means is to be installed on an experimental ship or the like deployed in the operating water area, and an aircraft such as a helicopter is flown over the operating water area, and a radio signal from the sonobuoy is transmitted. What is necessary is just to transmit to an experimental ship etc. via this aircraft.
[0011]
The sonobuoy of the present invention is a receiver that receives an acoustic signal that propagates in water and includes information about a transmission time, a positioning unit that receives radio waves from a satellite positioning system and outputs time information and position information, A distance calculation unit that calculates the distance over which the acoustic signal has propagated from a difference between the transmission time included in the signal and the current time output from the positioning unit; and a transmission unit that transmits the distance and the position information as a wireless signal. .
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, a preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of a position determination system according to an embodiment of the present invention.
[0013]
The operating water area of this position determination system is a test water area for performing a test of the underwater vehicle 1 and the like. In the test water area, a plurality of sonobuoys 2 are provided as buoys. In the illustrated example, it is assumed that a substantially square lattice is formed on the water surface, and the sonobuoys 2 are arranged corresponding to the lattice points. The sonobuoy 2 includes a main body 20 that gives buoyancy and stores an antenna and other circuit parts, and a receiver 21 suspended from the main body 20 at a predetermined depth in water. Here, three receivers 21 are provided for one sonobuoy 2 corresponding to positions at different depths. In this embodiment, it is not assumed that the sonobuoy 2 is collected after the test of the underwater vehicle 1 is completed. Therefore, there is no need to perform the withdrawal operation of the SONOBUY 2.
[0014]
A test boat 3 serving as a mother ship for testing the underwater vehicle 1 is navigating (or anchored) in the test water area, and a radio signal is transmitted from the sonobuoy 2 to the test boat 3 above the test water area. Helicopter 4 is flying to relay. On the aircraft of the helicopter 4, equipment for relaying wireless signals is provided. The test boat 3 is provided with an arithmetic unit (computer) for calculating the position of the underwater vehicle 1 in real time based on a radio signal from each sonobuoy 2. Of course, when all the sonobuoys 2 are located within the line of sight from the test ship 3, the test ship 3 receives the radio signals from the sonobuoy 2 directly without relaying by a helicopter. Is also good. Instead of dispatching the test boat 3, a computing device or the like may be arranged on land.
[0015]
Next, the underwater vehicle 1 to be a target of position determination will be described. The underwater vehicle 1 is equipped with a pinger 10 that periodically emits an acoustic signal toward the water. The sound signal emitted by the pinger 10 includes information indicating the transmission time of the sound signal and information indicating the identification (ID) number of the pinger 10 (substantially the identification number of the underwater vehicle 1). In order to transmit such information, the acoustic signal is modulated by PSK (phase shift keying) or FSK (frequency shift keying). Further, it is preferable to provide a depth measurement sensor such as a water pressure sensor on the pinger 10 so that information indicating the current depth of the underwater vehicle 1 is also included in the acoustic signal.
[0016]
FIG. 2 is a block diagram showing a configuration of such a pinger 10. As shown in FIG. The pinger 10 generally includes a time generator 11 configured as a clock circuit, a depth detector 12 that detects the depth of the pinger 10, and time information output from the time generator 11 and output from the depth detector 12. A signal generator 13 for periodically generating a signal including information on the own pinger's ID, transmission time and depth based on the depth information to be transmitted, and PSK or FSK based on the signal generated by the signal generator 13. A modulating unit 14 for performing modulation, a power amplifying unit 15 for amplifying an output of the modulating unit 14, a transmitter 16 provided on an output side of the power amplifying unit 15, and supplying power required by the pinger 10. And a battery 17. The wave transmitter 16 is an electroacoustic transducer, and is driven by the power amplifier 15 to transmit a Pinger transmitted wave signal which is an acoustic signal into water.
[0017]
As will be described later, in the position determination system of the present embodiment, the transmission time information included in the Pinger transmission signal transmitted by the Pinger 10 is based on the difference between the time when each sonobuoy 2 receives the Pinger transmission signal. Then, the distance between the pinger 10 and the sonobuoy 2 is calculated. Therefore, the time generation unit 11 of the pinger 10 needs to generate and output highly accurate time information. Therefore, a clock that maintains sufficient time accuracy at least during the test period of the underwater vehicle 1 is used as the time generation unit 11, and the time of the time generation unit 11 is set before the test of the underwater vehicle 1 starts. Alignment, that is, time alignment is performed. This time alignment is performed, for example, on the deck of the test boat 3. In order to obtain an accurate time, for example, the GPS receiver 19 that receives radio waves from a plurality of GPS satellites 5 may be used, and the time of the time generator 11 may be adjusted based on time information included in the GPS signal. In the present embodiment, since the time is acquired using the GPS in the sonobuoy 2, the time is synchronized between the pinger 10 and the sonobuoy 2 by performing the time alignment of the pinger 10 using the GPS. Time can be matched by order. The GPS receiving unit 19 is connected to the time generating unit 11 only when performing time matching.
[0018]
Next, the configuration of the sonobuoy 2 will be described with reference to FIG. The sonobuoy 2 receives the acoustic signal (pinger transmission signal) from the pinger 10, measures its own position and the current time by GPS, and based on the difference between the transmission time and the current time of the pinger transmission signal, the pinger A distance up to 10 is calculated, and the calculated distance, the ID and the depth of the target pinger 10, and its own position are transmitted to the test boat 3 via the helicopter 4. Such a sonobuoy 2 analyzes a plurality of receivers 21 that receive the Pinger transmission signal, the Pinger transmission signal received by the receiver 21, and the ID of the Pinger that has issued the Pinger transmission signal, A signal detection unit 22 for detecting the transmission time and depth, a GPS reception / positioning unit 23 for performing positioning by GPS and acquiring the current time, and up to the Pinger 10 based on the difference between the transmission time of the Pinger transmission signal and the current time , A distance calculation unit 24 that calculates the distance of the pinger 10, a distance to the pinger 10, and a positioning result (current position (latitude and longitude) of the sonobuoy 2) by the GPS reception / positioning unit. 25 that generates a modulated signal, a power amplifier 26 that amplifies the modulated signal output from modulator 25, and transmits a radio signal driven by power amplifier 26. And antenna 27, and a battery 28 for supplying power required across the sonobuoy 2.
[0019]
Next, the operation of determining and tracking the position of the underwater vehicle 1 by this position determination system will be described. FIG. 4 is a flowchart illustrating an operation method of the position determination system of the present embodiment.
[0020]
First, as shown in step 91, a water area (sea area) where the underwater vehicle 1 is to be tested is investigated. Here, as a marine environment survey, the water temperature distribution, tidal current, ambient noise, sea condition, and sonobuoy adjustment depth are determined. Next, in step 92, the drop position of the sonobuoy 2 is determined. The test ship 3 is dispatched, and in step 93, the time of the pinger 10 is adjusted on the test ship 3. Substantially in parallel with this, in step 94, the sonobuoy 2 is dropped into a predetermined position using an aircraft. Thereafter, in step 95, a system such as the on-board equipment of the helicopter 4 and the arithmetic unit of the test ship 3 is started up, and a system check and a wireless data link from the sonobuoy 2 to the test ship 3 via the helicopter 4 are established. Then, in step 96, the underwater navigation test of the underwater vehicle 1 is started, various tests are performed, and the position display and the position measurement data of the underwater vehicle 1 are recorded.
[0021]
When the underwater vehicle 1 is traveling in the water, the pingers 10 periodically transmit a pinger transmission signal (acoustic signal) including information on the transmission time, the pinger ID, and the depth into the water. And three or more sonobuoys 2 receive the Pinger transmission signal. The sonobuoy 2 that has received the Pinger transmission signal receives the difference between the transmission time of the received Pinger transmission signal and the current time acquired by the GPS reception / positioning unit 23 (that is, the reception time of the Pinger transmission signal) in water. By multiplying by the sound speed, the distance to the pinger 10 is calculated. A signal including the information indicating the distance and the information on the current position of the sonobuoy 2 is modulated, transmitted as a radio signal from the antenna 27, and transmitted to the test boat 3 via the helicopter 4. In FIG. 1, distances from the pinger 10 of the underwater vehicle 1 to the three sonobuoys 2 are indicated by R1, R2, and R3, respectively. In the test boat 3, the position of the pinger 10, that is, the position of the underwater vehicle 1 is calculated based on the current position of each sonobuoy 2 and the distances R1 to R3.
[0022]
During the test of the underwater vehicle 1, the sonic flow may cause the sonobuoy 2 to flow away from the test water area due to tides or the like. In such a case, in step 97, the Sonobuoy 2 is dropped into the test water area by the aircraft.
[0023]
After the test of the underwater vehicle 1 is completed, in step 98, the system such as the on-board device of the helicopter 4 and the arithmetic unit of the test boat 3 is terminated, and a series of operations is terminated.
[0024]
In the embodiment described above, the number of underwater vehicles to be position-determined is not limited to one. Since the ID is included in the Pinger transmission signal, the underwater vehicle can be identified by this ID. Therefore, even if two or more underwater vehicles exist in the test water area, It is possible to obtain the position of the underwater vehicle independently. In the present embodiment, since an acoustic signal modulated by PSK or FSK is used as the Pinger transmission signal, it is hardly affected by undersea noise or multipath. Further, since the position determination cycle of the underwater vehicle 1 depends on the transmission cycle of the Pinger transmitted signal irrespective of the arrangement interval of the sonobuoys, the position determination cycle is practically not limited, and The determination cycle can be determined appropriately. The acoustic frequency of the Pinger transmission signal may be appropriately determined according to the purpose of the test of the underwater vehicle 1 and the like. In the above-described embodiment, the distance from the sonobuoy 2 to the pinger 10 is calculated by the sonobuoy 2, but the speed of sound in water can change depending on the temperature, the tide, and the like, and these are accurately corrected. For this reason, the sonobuoy 2 calculates only the difference between the transmission time and the reception time of the pinger transmission signal and transmits the difference to the test boat 3, and performs a detailed correction of the sound speed on the test boat 3 while performing the distance from the sonobuoy 2 to the pinger 10. And the position of the underwater vehicle 1 may be obtained.
[0025]
In the present embodiment, it is possible to obtain the three-dimensional position of the underwater vehicle 1 in water by receiving the Pinger transmission signal in at least three sonobuoys 2. However, since the position determination accuracy in the depth direction is often worse than the position determination accuracy in the in-horizontal direction, the depth information obtained by the depth detection unit 12 of the pinger 10 is used, or the difference is different in the sonobuoy 2. The depth of the underwater vehicle 1 may be determined based on which of the plurality of receivers 21 provided at the depth has received the Pinger transmission signal most strongly.
[0026]
Further, in the present embodiment, each sonobuoy 2 receives a GPS radio wave from the GPS satellite 5 so that the sonobuoy 2 can measure its own position. In order to improve the accuracy of determining the position of the underwater vehicle, it is necessary to improve the accuracy of determining the position of the sonobuoy 2. In the sonobuoy 2, instead of determining its own position by a single GPS positioning, DGPS ( It is preferable that the position is determined by a differential GPS) method.
[0027]
Next, another embodiment of the present invention will be described with reference to FIG. In the position determination system shown in FIG. 1, the underwater vehicle 1 is equipped with a pinger, and the time of the time generator 11 of the pinger is adjusted, for example, on a ship, before the position of the underwater vehicle is determined. However, depending on the type and use of the underwater vehicle, it may be difficult to perform time alignment on the ship. Therefore, in this embodiment, a position determination system that does not require time alignment work on the underwater vehicle will be described.
[0028]
The difference between the position determination system shown in FIG. 5 and that shown in FIG. 1 is that one or more sound source buoys 6 are provided in the test water area, and that the underwater vehicle 1 has a responder 7 instead of a pinger. In that it is equipped.
[0029]
The sound source buoy 6 transmits a response request signal as an acoustic signal underwater, and, like the sonobuoy 2, can acquire the current position and the current time by GPS. When transmitting the response request signal, the sound source buoy 6 is configured to transmit the transmission time and the current position to the test boat 3 via the helicopter 4 by radio signals. Such a sound source buoy 6 includes a main body unit 60 that provides buoyancy and stores an antenna, a GPS receiving circuit, and the like, and a transmitter 61 that is suspended from the main body unit 60 in the water and emits a response request signal into the water. I have.
[0030]
On the other hand, the responder 7 mounted on the underwater vehicle 1 emits a response signal as an acoustic signal into the water in response to a response request signal from the sound source buoy 6. This response signal is received by three or more sonobuoys 2 out of the plurality of sonobuoys 2 provided in the test water area. The sonobuoy 2 having received the response signal wirelessly transmits the information indicating the current position of the sonobuoy 2 to the test boat 3 via the helicopter 4 together with the information indicating the reception time. The arithmetic unit in the test boat 3 receives the reception time of the response signal at each sonobuoy 2, the current position of each sonobuoy 2, the time when the sound source buoy 6 sends the response request signal, and the sound source buoy at that time. The position of the underwater vehicle 1 is calculated based on the position 6. In FIG. 5, the distance from the sound source buoy 6 to the underwater vehicle 1 is indicated by R1, and the distance from the underwater vehicle 1 to each sonobuoy 2 is indicated by R2 to R4. Therefore, if the response delay time at the responder 7 is ignored, the time from when the response request signal is issued at the sound source buoy 1 to when the response signal is received at each sonobuoy 2 corresponds to R1 + R2, R1 + R3, and R1 + R4, respectively. It's time to do it.
[0031]
In this embodiment, a tone burst signal or a signal modulated by PSK or FSK can be used as the response request signal and response signal. If a tone burst signal is used for the response request signal and the response signal, a response request signal is provided for each of the sound source buoys 6 so that the sound source buoys 6 can be identified when a plurality of sound source buoys 6 are operated. Is preferably changed. The responder 7 also changes the frequency of the response signal for each underwater vehicle to enable identification of the underwater vehicle 1 and responds to the frequency of the response request signal from the sound source buoy 6. Preferably, the frequency of the signal is changed. When the tone burst signal is used for the response request signal and the response signal, the configurations of the sound source buoy 6 and the responder 7 are simplified, but are more susceptible to undersea noise and multipath.
[0032]
On the other hand, in the case of using PSK or FSK-modulated signals for the response request signal and the response signal, IDs are assigned to the sound source buoy 6 and the responder 7, respectively, so that the sound source buoy 6 and the underwater vehicle 1 are identified. I do. Specifically, the response request signal includes the ID of the sound source buoy 6 that has issued the response request signal, and the responder 7 that has received such a response request signal includes the response signal in the response request signal together with its own ID. (ID of the sound source buoy 6). By using a PSK or FSK modulated signal for the response request signal and the response signal, it is less susceptible to undersea noise and multipath.
[0033]
The configuration in which the sound source buoy 6 is used and the underwater vehicle 1 is equipped with the responder has been described above. However, in this configuration, since the response request signal and the response signal do not include time information, the response request signal When the repetition frequency of the transmission is high, it becomes impossible to determine whether the response signal received by the SONOBUY 2 corresponds to the current response request signal or the previous response request signal. 1 cannot be determined. Therefore, the cycle of determining the position of the underwater vehicle 1 is limited by the arrangement interval of the sonobuoys 2, and is not suitable for determining the position at a high frequency. In the configuration shown in FIG. 5 as well, it is effective to provide a plurality of receivers 21 having different depths in each sonobuoy 2 in order to improve the positional accuracy in the depth direction.
[0034]
【The invention's effect】
As described above, the present invention deploys a sonobuoy that can measure its own position by a satellite positioning system in the operating sea area, thereby eliminating the need to lay sensors or transponders on the bottom of the water, thereby enabling the position of the underwater vehicle to be adjusted. This has the effect of enabling accurate measurement in real time.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a position determination system according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of a pinger.
FIG. 3 is a block diagram showing a configuration of a sonobuoy.
FIG. 4 is a flowchart showing an operation method.
FIG. 5 is a diagram showing a configuration of a position determination system according to another embodiment of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 underwater vehicle 2 sonobuoy 3 test ship 4 helicopter 5 GPS satellite 6 sound source buoy 7 responder 10 pinger 11 time generator 12 depth detector 13 signal generator 14, 25 modulator 15, 26 power amplifier 16, 61 Devices 17, 28 battery 19 GPS receiver 20, 60 body 21 receiver 22 signal detector 23 GPS receiver / positioner 24 distance calculator 27 antennas 91 to 98 Step

Claims (11)

A position determination system for determining a position of an underwater vehicle,
Sound generating means provided on the underwater vehicle to emit an acoustic signal into the water,
Sonobui which is provided in a plurality of operational waters, receives the acoustic signal from the sounding body, and measures its own position by a satellite positioning system,
Position calculation means for calculating the position of the underwater vehicle based on the reception timing of the acoustic signal at three or more of the sonobuoys and the position of the sonobuoy;
A positioning system comprising: A position determination system for determining a position of an underwater vehicle,
A pinger that is mounted on the underwater vehicle, performs clock adjustment prior to underwater navigation of the underwater vehicle, and emits an acoustic signal containing information indicating a transmission time into water.
A plurality of sonobuoys arranged in the operational water area, receiving the acoustic signal from the pinger, and measuring the current position and the current position by a satellite positioning system,
Position calculation means for calculating the position of the underwater vehicle based on the propagation time of the sound signal received from each of the three or more sonobuoys from the pinger to the sonobuoy and the position of the sonobuoy. ,
A positioning system comprising: The position determination system according to claim 2, wherein the acoustic signal is modulated by PSK or FSK and includes information on the identification number of the pinger. The sonobuoy has a distance calculating unit that calculates a propagation distance of the acoustic signal from a propagation time of the received acoustic signal from the pinger to the sonobuoy, and the position calculation unit performs the propagation corresponding to the propagation time. The position determination system according to claim 2, wherein the position of the underwater vehicle is calculated using time. The position determination system according to any one of claims 2 to 4, wherein the clock of the pinger is adjusted using the satellite positioning system. A position determination system for determining a position of an underwater vehicle,
A sound source buoy that is located in the operational waters, emits a first acoustic signal into water, and measures its own position by a satellite positioning system;
A responder mounted on the underwater vehicle and emitting a second acoustic signal underwater in response to the first acoustic signal;
A plurality of sonobuoys arranged in the operation water area, receiving the second acoustic signal from the responder, and measuring the own position by a satellite positioning system,
Position calculation means for calculating the position of the underwater vehicle based on the reception timing of the second sound signal received at each of the three or more sonobuoys, the position of the sonobuoy, and the position of the sound buoy When,
A positioning system comprising: The position determination system according to any one of claims 1 to 6, wherein the satellite positioning system is a global positioning system (GPS). 8. The device according to claim 1, wherein the sonobuoy has a plurality of receivers corresponding to different depths, and three-dimensional position localization is performed based on signals obtained by the plurality of receivers. 9. Positioning system as described. The position determination system according to any one of claims 1 to 8, wherein the sonobuoy and the position calculation unit are connected by a wireless line. A receiver that receives an acoustic signal that propagates in the water and includes information about a transmission time,
A positioning unit that receives radio waves from the satellite positioning system and outputs time information and position information,
A distance calculation unit that calculates the distance that the audio signal has propagated from the difference between the transmission time included in the audio signal and the current time output from the positioning unit,
A transmitting unit that transmits the distance and the position information as a wireless signal,
, Sonobuoy. The sonobuoy according to claim 10, wherein the satellite positioning system is a global positioning system (GPS).

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