JP5769119B2 - Underwater acoustic positioning system - Google Patents

Description

  The present invention relates to an underwater acoustic positioning system that observes crustal movements and the like of the seabed using acoustic signals. The present invention measures the crustal deformation of the sea floor by accurately measuring the distance between the shipboard station and the seafloor station, and computes the observed data at the shipboard station or on land, thereby calculating the crustal deformation of the seabed. The present invention relates to an underwater acoustic positioning system that can know the degree. In addition, the underwater acoustic positioning system of the present invention can obtain a lot of more accurate data in a short time, and improves the acquisition density of position data for the submarine station without changing the ID code of the existing submarine station. It can be made to.

  Since GPS radio waves or light does not reach the seabed accurately, it has been difficult to observe the extent of crustal movement on the seabed. The crustal movement on the sea floor can be measured by determining the position of the shipboard station using GPS and receiving a response signal of an acoustic signal emitted from the shipboard station toward the seabed station. However, since the speed of sound of the acoustic signal in the sea changes from time to time depending on seawater temperature, salinity concentration, etc., it has been difficult to accurately grasp in time and space. On the other hand, the observation device installed in the shipboard station accurately determines the position of the acoustic transducer of the shipboard station that emits an acoustic signal because the ship itself moves in at least three directions of rolling, pitching, and yawing. It was difficult.

  In addition, many surveys of the sea floor have been conducted for many years to predict earthquakes caused by crustal deformation. The submarine station set up by the Japan Coast Guard sends back a ranging signal using its called ID code. The number of maritime stations established by the Japan Coast Guard has already reached a considerable number. The underwater acoustic positioning system has the merit that an off-the-shelf system can be used, but instead of transmitting an ID code and a ranging signal from the shipboard station, it is received at the submarine station, and the same ID code is used for all the ranging signals. I was supposed to reply with it. Since the data transmission / reception time takes a long time, changes in seawater temperature and salinity concentration are often not constant, and accurate data cannot be obtained.

  Therefore, in the invention according to Japanese Patent Application No. 2013-102097 (filed on May 14, 2013) proposed by the present applicant, the shipboard station sends the same ID code and the same ranging signal to each maritime station. The ID code and the same distance measurement signal were sent back from the maritime station to the ship station. Since the underwater acoustic positioning system performs transmission and reception at the same time, the time required for measurement can be shortened and a large amount of accurate data can be obtained. However, the underwater acoustic positioning system has a problem that an ID code attached to a submarine station installed by the Japan Coast Guard cannot be used as it is.

JP-A-8-189969

  In the invention described in the above publication (JP-A-8-189969), the shipboard station transmits the ID code S1 and the ranging signal M to one of the submarine stations. The submarine station transmits an ID code S6 (predetermined by the Japan Coast Guard) and a ranging signal M as response signals to the shipboard station. Similarly, the shipboard station sequentially transmits and receives to other submarine stations. The ID code S6 and the ranging signal M are transmitted from each submarine station to the shipboard station with a time difference of 10 seconds, for example. Such data transmission / reception between the shipboard station and the submarine station is not only time consuming, but the data obtained at the first submarine station and the data obtained at the last submarine station are the seawater temperature and salinity, However, there is a drawback in that it is inaccurate.

  6 and 7 show another conventional example (Japanese Patent Application No. 2013-102097, filed on May 14, 2013), which is an underwater acoustic positioning system for removing the above-mentioned drawbacks. 6 and 7, in the underwater acoustic positioning system, a transducer 611 is provided on the bottom of an onboard station 61 equipped with GPS, and a plurality of submarine stations 62 (m1, m2, m3, m4,.・) Is laid. The shipboard station 61 includes at least a GPS for accurately knowing the position of the ship and a transducer 611 that transmits and receives signals to the submarine station 62 (m1, m2, m3, m4,...). The shipboard station 61 is a system in which the shipboard station 61 receives the sound signal returned from the submarine station 62 after transmitting the sound signal oscillated from the transducer 611 to the seabed station 62.

  The acoustic signal sent back from the submarine station 62 (m1, m2, m3, m4,...) Is received by the acoustic transducer 611, and then received by the GPS provided in the shipboard station 61. The position of the station 62 is calculated. The GPS is based on GPS observation data on land. The observation can be performed every several months, for example, to determine how the position of the submarine station 62 has changed.

  The underwater acoustic positioning system transmits an acoustic signal (ID) from the acoustic transducer 611 toward the plurality of submarine stations 62 (m1, m2, m3, m4,...) Installed on the seabed from the shipboard station 61. The code S0 and the ranging signal M) are transmitted. Thereafter, the submarine station 62 that has received the acoustic signal from the transducer 611 sends response data to the shipboard station 61 almost simultaneously. The acoustic signals (S1, S2, S3, S4,..., And M) of the respective submarine stations 62 (m1, m2, m3, m4,...) Received by the shipboard station 61 are the respective positions (distances). Are collected with slightly different time differences. Each piece of data is processed by a data processing device (not shown), so that position information of the submarine station 62 can be obtained. In the conventional underwater acoustic positioning system, the measurement results return almost simultaneously from each submarine station 62 (m1, m2, m3, m4,...) In one call from the shipboard station 61. It is possible to efficiently obtain data before conditions such as seawater temperature and salinity change from moment to moment.

  Since the underwater acoustic positioning system sends ID codes and ranging signals all at once and simultaneously receives them at the shipboard station, a large amount of data can be acquired in a short time and efficiency can be improved. However, when the submarine station 62 sends back data, different ID codes (S1, S2, S3, S4,...) Are attached. In the underwater acoustic positioning system, a submarine station with a different ID code (S1, S2, S3, S4,...) Cannot use facilities currently installed on the seabed. It was necessary to install submarine stations with different ID codes. Installation of the new submarine station requires enormous costs and labor, and has a very difficult problem of choosing between data accuracy and cost.

  In recent years (after the Great Tohoku Earthquake), the probability of a large earthquake occurring has increased. It is possible to predict the earthquake in the near future by accurately observing the crustal deformation of the seabed. The crustal movement of the sea floor cannot be observed by radio waves or light, so there was no means other than using acoustic signals. However, as described above, the speed of the acoustic signal not only changes depending on the seawater temperature, the salinity concentration, the state of the shipboard station, etc., but it is easy to pick up various noises that are derived temporally and spatially.

  In order to solve the problems as described above, the present invention transmits different ID codes and ranging signals from the shipboard station to the respective submarine stations with a certain time difference, and the same ID code from the maritime station and the different ones. It is an object of the present invention to provide an underwater acoustic positioning system capable of examining crustal movements with less error by analyzing after receiving each signal at the shipboard station by transmitting a return signal in the order in which the ranging signals arrive. To do. In addition, the present invention can transmit and receive an ID code and a distance measurement signal to and from the submarine station with a certain time difference between the shipboard station and the submarine station, and then analyze these signals so that the crustal deformation with less errors can be obtained. It is an object of the present invention to provide an underwater acoustic positioning system capable of examining

(First invention)
The underwater acoustic positioning system of the first invention receives acoustic signals transmitted from a shipboard station equipped with GPS based on GPS observation data on land at each of a plurality of submarine stations installed on the seabed, and each submarine station By transmitting the acoustic signal from the shipboard station to the shipboard station, it is possible to improve the acquisition density of the position data of the seabed station, and an ID code assigned to each shipboard station individually from the shipboard station and a board station transmitting unit that transmits the time difference of the lowest with a not interference with each other an acoustic signal consisting of ranging signals for each of said submarine station, which receives the respective acoustic signals from the ship station transmitting unit, the received only when the ID code in the audio signal is the one assigned to the own station, the predetermined same ID code above to all seafloor Immediately return the M-sequence code used in the existing submarine station, subjected to the ranging signal in the acoustic signal received, in the order in which the acoustic signal transmitted from the onboard station arrives that was in Japan Coast Guard has established the In the submarine station transmitting and receiving unit for transmitting signals, one onboard station receiving unit that simultaneously receives each reply signal returned immediately in the order received from the respective submarine station transmitting and receiving unit, and the one onboard station receiving unit, And a data processing device capable of immediately performing a calculation for determining the position of the submarine station transmitting / receiving unit on the basis of each return signal and a position signal from the GPS.

(Second invention)
In the underwater acoustic positioning system according to the second aspect of the invention, the time n from the start of transmission of the ID code to the end of transmission of the ranging signal is 0.4 seconds or more. The time until the ID code transmission is started is 2.6 seconds or less.

  According to the present invention, the ID code (S1, S2,...) And the ranging signal (M1, M2,...) Are transmitted from the shipboard station to the submarine station with a certain time difference, and then each submarine. Attaching the same ID code S6 from the station and returning the ranging signals (M1, M2,...) To each submarine station in order to know the crustal movement from many observation points in a short time Accurate data can be obtained.

  According to the present invention, since the ID code and ranging signal from the shipboard station are transmitted to the submarine station with a certain time difference, they are all returned from the submarine station with the same ID code S6. Submarine stations can be used, and not only can the time required for transmitting and receiving acoustic signals be reduced, but also inexpensive and accurate data can be collected in a short time.

  According to the present invention, by defining the time from the start of transmission of the ID code to the end of transmission of the ranging signal, the overall time taken for transmission and reception is shortened, and the seawater temperature and salinity concentration, The influence of the position and tilt (pitching etc.) could be reduced.

  According to the present invention, the time required for all measurements is shortened by providing the minimum time in consideration of distortion of the acoustic signal between the ID code and the distance measurement signal.

FIG. 1 is a schematic diagram for explaining an example in which an ID code and a distance measurement signal are transmitted to a submarine station with a predetermined time difference according to an embodiment of the present invention. FIG. 2 is an embodiment of the present invention, and is a schematic diagram for explaining an example in which each ranging signal with the same ID code is sent back to the shipboard station in each submarine station. FIG. 3 is a diagram for explaining an example in which an ID code and a distance measurement signal are transmitted from the shipboard station and a reply signal in response to the order of arrival of the signals is received by the shipboard station according to the embodiment of the present invention. FIG. 4 is a block diagram for explaining an aquarium test regarding M-sequence overlapping signal data when signals are transmitted in the same manner as in the present invention. FIG. 5 is a diagram for explaining that a good correlation processing result was obtained even with the overlapping distance measurement signals actually obtained by the present embodiment. FIG. 6 is a diagram illustrating a conventional example in which an ID code and a ranging signal are transmitted from a shipboard station to a submarine station, and the submarine station responds and is received by the shipboard station. FIG. 7 is a diagram for explaining an example in which replies are sent from the submarine station to the shipboard station all at once.

(First invention)
The underwater acoustic positioning system of the present invention is a submarine station having an ID code transmitted from an acoustic transducer of a shipboard station to each submarine station and a ranging signal with a certain time difference and each ID code installed on the seabed. Receive at. The certain time difference is a certain time that does not cause mutual interference from the shipboard station, and is the minimum time that does not cause mutual interference. Thereafter, the respective acoustic signals (ID code and ranging signal) are immediately returned to the shipboard station in the order of arrival at the respective submarine stations. On the other hand, the correct position of the shipboard station is calculated by the GPS provided in the shipboard station. The returned ranging signal is combined with the GPS position to calculate the correct position of the submarine station. The GPS is based on GPS observation data on land. The calculated result can be used to determine how the position of the submarine station has moved or changed on the ground, and is used as data for predicting an earthquake.

  The underwater acoustic positioning system of the present invention can not only use the ID code of the already installed submarine station in the submarine station, but also improve the transmission / reception density of the ID code and the distance measurement signal, thereby It is possible to improve the acquisition density of the position data of the submarine station and collect it. In addition, the underwater acoustic positioning system of the present invention does not require a new submarine station and can use an existing one installed by the Japan Coast Guard, so that enormous costs and labor are not required. The present invention not only shortens the overall measurement time by using the same ID code for already installed submarine stations and different ranging signals, but also provides accurate and inexpensive measurement data. It became possible to get.

  The underwater acoustic positioning system of the present invention comprises an ID code (S1, S2,..., For example, 256 bits) from the acoustic transducer toward a plurality of submarine stations installed on the seabed from the shipboard station equipped with the GPS. M-sequence codes) and ranging signals (M1, M2,..., For example, 512-bit M-sequence codes) are immediately transmitted to each of the submarine stations with a certain time difference. The acoustic signal from the shipboard station transmitter is received by the submarine station having the determined ID code. Each of the submarine stations is attached with the same predetermined ID code S6, and returns a ranging signal with a different code transmitted from the shipboard station in the order of arrival. The shipboard stations can be easily identified because the ranging signals are different codes even if the ID codes are the same.

  The fact that all the submarine stations attach the same ID code S6 has an advantage that the submarine station system already installed on the seabed can be used as it is. The underwater acoustic positioning system of the present invention not only shortens the time between each ID code and the ranging signal, but also can use an ID code attached to an existing submarine station. The data obtained is accurate and the data collection efficiency is high.

  The submarine station transmission / reception unit receives the acoustic signals from the shipboard station transmission unit and transmits the same ID code S6 determined in advance. And save time and effort. Further, since the shipboard station receiver returns immediately in the order of arrival at each of the submarine stations, the entire measurement time can be shortened.

  At the shipboard station, the received data is brought back on the ship or on the ground, and the data processor performs an operation to determine the position of the submarine station. The underwater acoustic positioning system of the present invention sends each acoustic signal with a constant time difference and with a minimum time difference, and immediately sends it back in the order in which the data arrived, so that the total time from transmission to reception of the acoustic signal is received. Therefore, a large amount of data can be collected efficiently in a short time with little influence of changes in seawater temperature and salinity. In general, the onboard station transmitting unit and the onboard station receiving unit are integrated transmission / reception devices provided in the onboard station, and are described separately for convenience of explanation.

  Since the ID code (M sequence code -256 bits) and ranging signal (M sequence code -512 bits) of the present invention are composed of different numbers of bits determined in advance, the ID code and ranging signal received by the shipboard station Many accurate data can be obtained without signal interference. In addition, the underwater acoustic positioning system of the present invention can reduce noise from signal transmission to reception even though the propagation speed of the acoustic signal is slow (1500 m / sec in the sea).

(Second invention)
The underwater acoustic positioning system of the second invention defines the time of the ID code and ranging signal. The time obtained by adding the ID code and the distance measurement signal is 0.1 second because the ID code is an M-sequence code having 256 bits. Further, since the distance measurement signal is an M-sequence code consisting of 512 bits, 0.2 second is required. Since these signals are mechanical between the ID code and the distance measurement signal, 0.1 second is required. Therefore, the time n obtained by adding the ID code and the distance measurement signal is at least 0.4 seconds. Further, since the signal is mechanical, it is necessary to provide some time between the time when the first ranging signal is finished and the next ID code, and after the first ranging signal is finished. In the present invention, it was found that the time until the start of transmission of the next ID code is preferably 2.6 seconds or less.

  The said time of the underwater acoustic positioning system of this invention is a standard time, and is a time when an ID code and a ranging signal do not interfere with noise etc. These times should be as small as possible. However, since the acoustic signal uses mechanical distortion, the time is provided to cope with vibration stabilization and delay such as AGC (gain control).

  In the underwater acoustic positioning system of the present invention, the total time required for one transmission / reception performed between the shipboard station and the submarine station is preferably between 7 seconds and 10 seconds. For example, when the submarine station is located at a distance of 5000 m, the distance between the shipboard station, the submarine station and the shipboard station is a maximum of about 10,000 m for a round trip, and when the data storage time is added, it is 7 seconds + 3 seconds = 10 seconds. It is desirable to be. If the time is too long, it takes too much time to collect all the data. Since the underwater acoustic positioning system is performed based on severe working conditions at sea, 10 seconds is the optimum time.

  FIG. 1 is a schematic diagram for explaining an example in which an ID code and a distance measurement signal are transmitted to a submarine station with a predetermined time difference according to an embodiment of the present invention. FIG. 2 is an embodiment of the present invention, and is a schematic diagram for explaining an example in which each ranging signal with the same ID code is sent back to the shipboard station in each submarine station. 1 and 2, the underwater acoustic positioning system is provided with a transducer 111 on the bottom of an onboard station 11 equipped with GPS, and a plurality of submarine stations 12 (m1, m2, m3, m4,.・) Is laid. The shipboard station 11 includes at least a GPS for accurately knowing the position of the ship and a transducer 111 capable of transmitting and receiving toward the submarine station 12 (m1, m2, m3, m4,...).

  The shipboard station 11 transmits the acoustic signal (ID code and ranging signal) oscillated from the transducer 111 toward the submarine station 12 with a certain time difference. Different ID codes S1, S2,... Are assigned to the submarine stations 12. Further, the ranging signal is given M1, M2,... Different depending on each submarine station 12. After receiving the acoustic signal transmitted from the shipboard station 11, the submarine station 12 returns the same ID code S6 and different ranging signals (M1, M2,...) To the shipboard station 11 in the order of arrival. To do.

  The returned acoustic signal from the submarine station 12 (m1, m2, m3, m4,...) Is received by the acoustic transducer 111, and then transmitted to the submarine by the GPS provided in the shipboard station 11. The position of the station 12 is calculated. The GPS is based on GPS observation data on land. For example, the observation can be performed every several months to determine how the position of the submarine station 12 has changed.

  FIG. 3 is a diagram for explaining an example in which an ID code and a distance measurement signal are transmitted from the shipboard station and a reply signal in response to the order of arrival of the signals is received by the shipboard station according to the embodiment of the present invention. In FIG. 3, the acoustic signal transmitted to the submarine station m1 is composed of an ID code S1 and a ranging signal M1, and is transmitted from the shipboard station 11 to the submarine station 12. The ID code S1 is an M-sequence code (256 bits), and the ranging signal M1 is an M-sequence code (512 bits). The ID code S1 is composed of different bits with the same sequence. A lot of accurate data can be obtained without interference between the code and the distance measurement signal. In addition, the underwater acoustic positioning system of the present embodiment can reduce noise entering from signal transmission to reception despite the low propagation speed of the acoustic signal in the sea (1500 m / sec in the sea). .

  The M-sequence code is a pseudo-random signal generated based on an artificial rule. These signals have the property that the autocorrelation value shows a sharp peak and at the same time the correlation value with other than itself is extremely low. Therefore, the signal has an advantage that the propagation time can be correctly determined by the correlation processing even when the received signal is unclear due to ambient noise or the like.

  The underwater acoustic positioning system according to the present embodiment has an acoustic signal (ID code S1, ID code S1,...) With a certain time difference from the acoustic transducer 111 toward the plurality of submarine stations 12 installed on the seabed from the shipboard station 11 equipped with the GPS. S2, S3,... And ranging signals M1, M2, M3,. Thereafter, the submarine station 12 that has received the acoustic signal from the transducer 111 sends response data toward the shipboard station 11 in the order in which the acoustic signal has arrived. The acoustic signal from the submarine station 12 is different from the common ID code S6 attached to the submarine station, and ranging signals (M1, M2, M3,...) Sent from the shipboard station 11 are different. ) And reply. The shipboard station 11 collects the acoustic signals (S6 and M1, M2, M3,...) With a slightly different time difference depending on their positions (distances).

  Each data is processed by a data processor (not shown), so that the position information can be obtained accurately and quickly using the offshore substation 12 already laid by the Japan Coast Guard. it can. Since the ID code is an M-sequence code (256 bits), it is 0.1 seconds, and the distance measurement signal is an M-sequence code (512 bits). It was. Further, since these signals use mechanical distortion between the ID code (S1, S2, S3,...) And the distance measurement signals (M1, M2, M3,...). It was found that 0.1 second was necessary. Therefore, the time n required for the acoustic signal sent from the shipboard station 11 to the submarine station is the total time of the ID code, the space, and the ranging signal, and is at least 0.4 seconds. Further, it was found that the time from the end of transmission of the ranging signal to the start of transmission of the next ID code is preferably 2.6 seconds or less in consideration of the space.

  In addition, the time provided between the ID code and the distance measurement signal is 0.1 seconds, but it is standard, and even if there is some noise, the ID code and the distance measurement signal It ’s time not to interfere. These times should be as small as possible. However, since the acoustic signal uses mechanical distortion, the time is provided to cope with vibration stabilization and delay such as AGC (gain control). Yes.

  Considering the case where the submarine station is located at a distance of 5000 m, the longest round trip is about 10,000 m, and the propagation time of the acoustic signal passes through the shipboard station-the submarine station-the shipboard station. And about 7 seconds + 3 seconds (storage time) = 10 seconds. If the time is too long, it takes too much time to collect all the data. Since the underwater acoustic positioning system is performed based on severe working conditions at sea, 10 seconds is the optimum time.

  The underwater acoustic positioning system of the present embodiment transmits a reply signal in the order in which the acoustic signals transmitted to each submarine station 12 (m1, m2, m3, m4,...) Arrive at a certain time difference from the shipboard station 11. Therefore, ranging signals can be collected in a short time, and accurate data can be efficiently obtained before conditions such as seawater temperature and salinity concentration change every moment. That is, the distance measurement signal can be returned not only by using the ID code provided in the existing submarine station as it is, but also in the order determined by the positional relationship of the submarine stations arranged, so that the time required for collection is shortened. can do. Further, even if an existing ID code is used for the ranging signal returned from the submarine station, the identification rate can be improved because a different ID code is attached to the ranging signal.

  The receiving unit (not shown) of the shipboard station 11 is a reply signal sent from the transmitting / receiving unit (not shown) of the submarine station 12 (m1, m2, m3, m4,...). (S6 and M1, M2, M3,...) Are received. The receiving unit of the shipboard station 11 stores the return signal (S6 and M1, M2, M3,...) And the position signal from the GPS as data. The data is brought back to the ground at the shipboard station 11 or as data, and a calculation process for determining the position of the submarine station 12 is performed by a data processing device (not shown).

  Since the underwater acoustic positioning system of the present invention sends an acoustic signal with a certain time difference and returns a reply signal in the order of arrival at the submarine station, changes in seawater temperature, salinity concentration, etc. occur during the data processing time. A small amount of accurate data can be collected efficiently in a short time. In general, the transmitting unit in the onboard station and the receiving unit in the onboard station of this embodiment are an integral transmitting / receiving device provided in the onboard station, and are described separately for convenience of explanation.

  Next, the results of the water tank experiment of the present invention will be described with reference to FIGS. 4 and 5. FIG. 4 is a block diagram for explaining an aquarium experiment for obtaining data. In FIG. 4, the test water tank 41 is 2650 mm long × 1750 × width deep 620 and artificial seawater 414 (which is prepared by dissolving sodium chloride as a main component in fresh water to a salt concentration of about 35%). .) Is filled. Inside the test water tank 41, a transmitting hydrophone 411 and a transmitting hydrophone 412 are placed at a depth of 200 mm in a state of being separated from each other by 300 mm. Is arranged.

  The transmission hydrophones 411 and 412 are connected to the transmission channel 1 and the transmission channel 2 of the transmission device 43, respectively. The receiving hydrophone 413 is connected to a receiving device 42. The receiving device 42 and the transmitting device 43 can send necessary signals to the hydrophones of the test water tank 41 and obtain necessary data by the A / D conversion board and the D / A conversion board. The receiving device 42 and the transmitting device 43 are connected to a data processing device 44. The transmission device 43 and the reception device 42 are set to 200 k · / ch. The data processing device 44 performs M-sequence signal transmission processing, reception signal recording processing, and correlation processing. The data storage device 45 stores and saves the received waveform data obtained by the data processing device 44 and includes a database of acoustic codes.

  FIG. 5 is a diagram for explaining that a good correlation processing result was obtained even with the overlapping distance measurement signals actually obtained by the present embodiment. 5A and 5B show waveforms when the same ID code S6 is attached to the distance measurement signal M1 and the distance measurement signal M2 in the test water tank 41 of FIG. 4 and delayed by a certain time, for example, 50 mm second. Data is shown. FIG. 5 (c) shows waveform data when (a) and (b) are received in duplicate. FIG. 5 (d) is the same as the duplicate signal of FIG. 5 (c), but is displayed with the amplitude direction (vertical axis) reduced. That is, in FIG. 5C, the vertical axis is enlarged in order to clarify the shape of the signal.

  The waveform data shown in FIG. 5 (e) shows that the correlation between the duplicated received signals can be identified in the portion surrounded by the round dotted line. The data processing device 44 uses the known response means, for example, Fourier expansion, as shown in FIG. 5 (c), using the response signal from the submarine station shown in FIGS. 5 (a) and 5 (b). Waveform data is generated. The experimental results as described above mean that the processing can be performed accurately on the actual sea as it is.

  As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example. The present invention can be modified in various ways without departing from the scope of the claims. The shipboard and submarine stations, transmission / reception apparatus, data processing apparatus, etc. of the present invention are composed of known communication engineering and acoustic engineering techniques, and can be modified without departing from the scope of the claims. .

11 ... Shipboard station 111 ... Transducer 12 (m1, m2, m3, ...) ... Submarine stations S1, S2, S3, ... ID codes M1, M2, M3, ... Distance signal

Claims (2)

Acoustic signals transmitted from a shipboard station equipped with GPS based on GPS observation data on land are received by a plurality of submarine stations installed on the seabed, and the acoustic signals are transmitted from the respective seabed stations to the shipboard station. In the underwater acoustic positioning system that can improve and collect the acquisition density of the position data of the submarine station,
An onboard station transmitter for transmitting an acoustic signal composed of an ID code and a ranging signal individually assigned to each submarine station from the onboard station with a minimum time difference that does not interfere with each other,
The same predetermined signal for all the submarine stations is received only when each of the acoustic signals from the shipboard station transmitter is received and the ID code in the received acoustic signals is assigned to the own station. An M-sequence code that is an ID code and used in an existing submarine station set up by the Japan Coast Guard is attached to a ranging signal in the received acoustic signal, and the acoustic signals transmitted from the shipboard station are received in the order of arrival. A submarine station transceiver that immediately sends a reply signal;
One shipboard station receiving unit that simultaneously receives the reply signals that are immediately returned in the order received from the respective submarine station transceiver units ;
In the one shipboard station reception unit, a data processing device capable of immediately performing an operation for determining the position of the submarine station transmission / reception unit on the basis of each return signal and the position signal from the GPS;
An underwater acoustic positioning system characterized by comprising at least.   The time n from the start of transmission of the ID code to the end of transmission of the ranging signal is 0.4 seconds or more, and the time from the end of transmission of the ranging signal to the start of transmission of the next ID code is It is 2.6 seconds or less, The underwater acoustic positioning system described in Claim 1 characterized by the above-mentioned.