JP2014232004A - Signal detecting apparatus and signal detecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent wrong detection of a seabed-reflected signal, which results from reflection of a sound wave from the seabed, as if it were a signal reflected from an object.SOLUTION: A transmitter 100 transmits a sound wave WA into the water. A receiver 200 receives a reflected signal WS of the sound wave WA outputted by the transmitter 100. A first reflected signal processor 310 generates, on the basis of the reflected signal WS received by the receiver 200, first reflected signal information that indicates relations among distances between the sources of signal components WB, WC and WD contained in the reflected signal WS and the receiver 200, times elapsed after the transmission of the sound wave WA by the receiver 200, and signal intensities of the signal components WB, WC and WD contained in the reflected signal WS.

Description

  The present invention relates to a signal detection device and a signal detection method, and more particularly to a signal detection device and a signal detection method for detecting a target by transmitting a sound wave into water and receiving a reflected signal of the sound wave.

  2. Description of the Related Art In recent years, a technique for detecting a target such as an underwater vehicle using a reflected sound wave signal is known. In this technique, first, a wave transmitting unit provided in the hull transmits sound waves into the water. The sound wave transmitted underwater collides with the target and is reflected. A receiving unit provided on the hull receives a reflected signal after colliding with a target. Then, the signal processing unit analyzes the reflected signal received by the receiving unit and detects the location of the target.

  In connection with the present invention, Patent Document 1 discloses a technique for illustrating the scattering intensity of a school of fish based on a reflected signal derived from a reflector such as a school of fish.

Japanese Examined Patent Publication No. 63-22275

  However, when the water temperature is high, the sound ray indicating the trajectory of the sound wave tends to bend vertically downward. That is, when the water temperature is high, the sound wave transmitted from the wave transmitting unit does not propagate far along the water surface, but tends to propagate vertically downward from the water surface. In this case, the sound wave transmitted from the transmission unit collides with the seabed at a position close to the transmission unit in the water surface direction. For this reason, there is a case where a seabed reflected signal, which is a reflected signal generated after a sound wave collides with the seabed, is detected with a large signal intensity. In this way, when a seafloor reflected signal having a large signal strength is received by the wave receiving section, the signal processing section often mistakenly recognizes the seafloor reflected signal as a reflected signal from a target to be originally detected. There was a problem that occurred.

  In particular, when the ship is moving and the reflected signal of the sound wave transmitted by the transmission unit is to be detected on the ship, the signal processing unit receives the signal from the target moving in the same direction at the same speed as the ship. In some cases, it was not possible to distinguish between a reflected signal and a reflected signal from the seabed.

  The present invention has been made in view of such circumstances, and an object of the present invention is to erroneously detect a seabed reflected signal, which is a reflected signal of a sound wave from the seabed, as a reflected wave from a target. It is an object of the present invention to provide a signal detection device and a signal detection method that solve the problem of preventing.

  The signal detection device of the present invention includes a wave transmission unit that transmits sound waves into water, a wave reception unit that receives a reflection signal of the sound waves output by the wave transmission unit, and the reflection that is received by the wave reception unit. Based on the signal, the distance between the source of each signal component included in the reflected signal and the receiving unit, the elapsed time after the receiving unit transmits the sound wave, and the reflected signal A first reflected signal processing unit that generates first reflected signal information indicating a relationship between the signal intensity of each signal component.

  The signal detection method of the present invention includes a sound wave transmission step of transmitting a sound wave by a wave transmission unit, a reflection signal reception step of receiving a reflection signal of the sound wave by a wave reception unit, and the reflection received in the reflection signal reception step. Based on the signal, the distance between the source of each signal component included in the reflected signal and the receiving unit, the elapsed time after the receiving unit transmits the sound wave, and the reflected signal A first reflected signal information generating step for generating first reflected signal information indicating the relationship between the signal intensity of each signal component.

  According to the signal detection device and the signal detection method of the present invention, it is possible to prevent the seabed reflected signal, which is a reflected signal of the sound wave from the seabed, from being erroneously detected as the reflected signal from the target.

It is a figure which shows the structure of the signal detection apparatus in the 1st Embodiment of this invention. It is a model perspective view which shows typically a mode that a target is detected using the signal detection apparatus in the 1st Embodiment of this invention. It is a figure which shows the operation | movement flow of the signal detection apparatus in the 1st Embodiment of this invention. It is a figure which shows the relationship between the sound speed in water and water depth. It is a figure which shows sound ray distribution by the relationship between water depth and distance. It is a figure which shows an example of 1st reflected signal information. It is a figure which shows an example of 2nd reflected signal information. It is a figure which shows the structure of the signal detection apparatus in the 2nd Embodiment of this invention. It is a figure which shows the operation | movement flow of the signal detection apparatus in the 2nd Embodiment of this invention. It is a figure which shows an example of 2nd reflected signal information.

<First Embodiment>
The configuration of the signal detection apparatus 1000 according to the first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of the signal detection apparatus 1000.

  As shown in FIG. 1, the signal detection apparatus 1000 includes a transmission unit 100, a reception unit 200, a signal processing unit 300, a first display unit 400, and a second display unit 500. Composed.

  The wave transmitting unit 100 is attached to, for example, a side surface of a hull, and transmits (emits) sound waves into water. The wave receiving unit 200 is attached to, for example, a side surface of the hull (the same side as the wave transmitting unit 100), and receives a reflected wave signal transmitted from the wave transmitting unit 100.

  The signal processing unit 300 performs predetermined signal processing on the reflected signal received by the wave receiving unit 200. The signal processing unit 300 includes a first reflected signal processing unit 310 and a second reflected signal processing unit 320.

  Based on the reflected signal received by the wave receiving unit 200, the first signal processing unit 310 determines the distance between the source of each signal component included in the reflected signal and the wave receiving unit 200, and the wave receiving unit 200 First reflection signal information indicating a relationship between an elapsed time after transmitting the sound wave and each signal component signal intensity included in the reflection signal is generated. As will be described later, the reflected signal includes a reflected signal component from the target, a seabed reflected signal component that is a reflected signal from the seabed, and a miscellaneous reflected signal component such as noise. The specific content of the first reflected signal information will be described in detail in the operation description described later.

  Based on the reflected signal received by the wave receiving unit 200, the second signal processing unit 320 determines the distance between the source of each signal component included in the reflected signal and the wave receiving unit 200, and the wave receiving unit 200. Second reflected signal information indicating the relationship between the direction of the source of each signal component included in the reflected signal when used as a reference and the signal intensity of each signal component included in the reflected signal is generated. As described above, the reflected signal includes a reflected signal component from the target, a seabed reflected signal component that is a reflected signal from the seabed, and a miscellaneous reflected signal component such as noise. The specific content of the second reflected signal information will be described in detail in the operation description described later.

  The first display unit 400 provides display of the first reflected signal information generated by the first signal processing unit 310. The first display unit 400 is also called a distance-time signal display unit.

  The second display unit 500 provides display of the second reflected signal information generated by the second signal processing unit 320. The second display unit 500 is also called a distance-azimuth signal display unit.

  The configuration of the signal detection apparatus 1000 has been described above.

  Next, the operation of the signal detection apparatus 1000 will be described.

  FIG. 2 is a schematic perspective view schematically showing how a target is detected using the signal detection apparatus 1000. FIG. 3 is a diagram illustrating an operation flow of the signal detection apparatus 1000. FIG. 4 is a diagram showing the relationship between the sound speed in water and the water depth. FIG. 5 is a diagram showing the sound ray distribution in relation to water depth and distance.

  As shown in FIG. 2, the signal detection device 1000 is attached to one side of the hull 2000 that is floating on the water surface. Here, it is assumed that the target 3000, which is the detection target of the signal detection device 1000, exists between the seabed 4000 and the water surface.

  Here, as shown in FIG. 4, the underwater sound velocity distribution assumes an environment in which the sound velocity decreases as the water depth increases toward the seabed. In this case, as shown in FIG. 5, the sound ray indicating the moving trajectory of the sound wave draws a trajectory that is bent sharply toward the seabed and propagates away from the sound source. In the example of FIG. 5, the movement trajectory of a sound wave when a sound wave of a predetermined output is transmitted and output underwater at three types of output angles is shown. As shown in FIG. 5, when sound waves are transmitted into water, it can be seen that the sound waves do not propagate in a straight line in water. That is, the sound wave propagates rapidly toward the sea bottom at a certain distance (horizontal distance along the water surface) from the sound wave generation source. Therefore, it can be said that the sound wave reaches only a certain distance from the sound wave at a horizontal distance. In such a case, it is known that in the region between each sound ray and the depth axis in FIG. 5, the sound wave is reflected on the sea bottom, so that a reflected signal having a strong signal intensity is detected. A case where the transmission sound wave WA is transmitted and output from the transmission unit 100 under such an environment will be specifically described.

  As shown in FIG. 2 and FIG. 3, first, the wave transmission unit 100 transmits and outputs the transmission sound wave WA from the side of the hull 2000 toward the water (S301). As shown in FIG. 2, the transmission sound wave WA propagates radially around the transmission unit 100 that is the transmission source. The transmitted sound wave WA is reflected after colliding with the target 3000 and the sea bottom 4000. As shown in FIG. 2, the reflected signal WB generated after colliding with the target 3000 propagates radially around the portion of the target 3000 where the transmission sound wave WA collides. The reflected signal WB is also referred to as a reflected signal generated from the target 3000 or a reflected signal from the target. Similarly, as shown in FIG. 2, the reflected signal WC generated after colliding with the seabed 4000 propagates radially around the portion of the seabed 4000 where the transmitted sound wave WA collided. Note that the reflected signal WC is also referred to as a reflected signal generated from the seabed 4000 or a seabed reflected signal.

  Next, the wave receiving unit 200 receives the reflected signal WS including the two reflected signals WB and WC (S303). Specifically, the wave receiving unit 200 is a reflection signal component WB having the target 300 as a generation source, a reflection signal component WC having the sea bottom 4000 as a generation source, and other than these reflection signal components WB and WC. The miscellaneous reflection signal component WD that causes noise is received. The wave receiving unit 200 outputs a reflected signal WS including the three reflected signal components WB, WC, and WD to the signal processing unit 300.

  Next, the first reflected signal processing unit 310 of the signal processing unit 300 performs beam phasing on the reflected signal WS received by the wave receiving unit 200, and generates first reflected signal information (S305). The first reflected signal processing unit 310 outputs the first reflected signal information to the first display unit 400.

  Next, the second reflected signal processing unit 320 of the signal processing unit 300 performs beam phasing on the reflected signal WS received by the wave receiving unit 200, and generates second reflected signal information (S307). Further, the second reflected signal processing unit 320 outputs the second reflected signal information to the second display unit 500.

  Here, it has been described that the process of S307 is performed after the process of S305. However, the process of S305 may be performed after the process of S307, or the processes of S305 and S307 may be performed simultaneously.

  Then, the first display unit 400 displays and provides the first reflected signal information, and the second display unit 500 displays and provides the second reflected signal information (S309).

  Here, as described above, the first reflected signal information is the distance D between the source of the signal components WB, WC, and WD included in the reflected signal WS and the receiving unit 200, and the receiving unit 200. This is information indicating the relationship between the elapsed time T after the transmission sound wave WA is transmitted and the signal strengths of the signal components WB, WC, and WD included in the reflected signal WS. Note that the distance D between the signal source WB, WC, WD generation source and the receiving unit 200 included in the reflected signal WS is the distance along the vertical direction with respect to the vertical direction in the normal transverse direction of the hull 2000. It is.

  FIG. 6 is a diagram illustrating an example of the first reflected signal information. In FIG. 6, the vertical axis indicates the elapsed time T after the wave receiving unit 200 transmits the transmission sound wave WA, and the horizontal axis indicates the generation of each signal component WB, WC, WD included in the reflected signal WS. A distance D between the source and the receiving unit 200 is set.

  As shown in FIG. 6, the first reflected signal information includes, for each component of the reflected signal WB from the target, the seafloor reflected signal WC, and the miscellaneous reflected signal WD, and the source of each signal component WB, WC, WD, and The relationship between the distance D between the wave receiving units 200, the elapsed time T after the wave receiving unit 200 transmits the transmission sound wave WA, and the signal strength of each signal component WB, WC, WD is included. In FIG. 6, the display is darker as the signal strength of the reflected signal WB, the seafloor reflected signal WC, and the miscellaneous reflected signal WD is stronger.

  As shown in FIG. 6, it can be seen that the miscellaneous reflection signal component WD and the seafloor reflection signal component WB are continuously present at a substantially constant distance. In contrast, the reflected signal component WB from the target exists at a specific time, and it can be seen that the distance D from the receiving unit 200 changes with time.

  Thus, by analyzing the first reflected signal information from the relationship between the distance D and the time T, each of the reflected signal component WB, the seafloor reflected signal component WC, and the miscellaneous reflected signal component WD from the target is obtained. Existence can be known in relation to the distance D from the receiving unit 200.

  Further, as described above, the second reflected signal information is the distance between the source of the signal components WB, WC, and WD included in the reflected signal WS and the receiving unit 200, and the receiving unit 200 as a reference. This is information indicating the relationship between the azimuth of the source of each signal component WB, WC included in the reflected signal WS and the signal intensity of each signal component WB, WC, WD included in the reflected signal WS.

  FIG. 7 is a diagram illustrating an example of the second reflected signal information. In FIG. 7, the vertical axis indicates the distance D between the source of the signal components WB, WC, and WD included in the reflected signal WS and the wave receiving unit 200, and the horizontal axis indicates the wave receiving unit 200. The direction S of the generation source of each signal component WB, WC, WD included in the reflected signal WS when used as a reference is set.

  As shown in FIG. 7, the second reflected signal information includes the distance D from the receiving unit 200 and the reflected signal component WB from the target, the seafloor reflected signal component WC, and the miscellaneous reflected signal component WD. The relationship between the direction S of the source of each signal component WB, WC, WD and the signal intensity of each signal component WB, WC, WD when using the wave receiving unit 200 as a reference is included. In FIG. 7, the display is darker as the signal intensity of the reflected signal component WB, the seafloor reflected signal component WC, and the miscellaneous reflected signal component WD is stronger.

  FIG. 7 shows the signal components WB, WC, and WD according to the signal strength. However, if no identifier is displayed, it is identified whether each reflected signal component displayed is a component of the reflected signal WB from the target, a component of the seafloor reflected signal WC, or a component of the miscellaneous reflected signal WD. I can't do it.

  On the other hand, when the second reflected signal information shown in FIG. 7 is illuminated with the first reflected signal information shown in FIG. 6, the sources and receivers of the signal components WB, WC, WD in the second reflected signal information are received. Each distance D between the wave parts 200 corresponds to each distance D between the source of each signal component WB, WC, WD obtained from the first reflected signal information shown in FIG. .

  Therefore, among the first reflected signal information shown in FIG. 6, the distance D where the reflected signal component WB from the target exists is correlated in FIGS. 6 and 7, and the second information shown in FIG. If the reflected signal component WB included in the reflected signal information is extracted, the orientation of the reflected signal component WB from the target can be detected.

  In this way, by using the information on the distance D of the reflected signal WB included in the first reflected signal information, the second reflected signal information is analyzed from the relationship between the distance D and the direction S, thereby receiving the wave. The direction S of the generation source of the reflected signal component WB from the target when the unit 200 is used as a reference can be detected.

  As described above, the signal detection apparatus 1000 according to the first embodiment of the present invention includes the transmission unit 100, the reception unit 200, and the first reflected signal processing unit 310. The wave transmission unit 100 transmits the sound wave WA into the water. The wave receiving unit 200 receives the reflected signal WB of the sound wave WA output from the wave transmitting unit 100. The first reflected signal processing unit 310 is based on the reflected signal W received by the wave receiving unit 200, between the generation source of each signal component WB, WC, WD included in the reflected signal WS and the wave receiving unit 200. First reflected signal information indicating the relationship between the distance D, the elapsed time T after the wave receiving unit 200 transmits the sound wave WA, and the signal strengths of the signal components WB, WC, and WD included in the reflected signal WS. Generate.

  As described above, the first reflected signal information generated by the first reflected signal processing unit 310 includes the signal components WB, WC, and WD included in the reflected signal WS between the generation source and the receiving unit 200. The relationship between the distance D, the elapsed time T after the wave receiving unit 200 transmits the sound wave WA, and the signal strengths of the signal components WB, WC, and WD included in the reflected signal WS is included. Therefore, the signal detection apparatus 1000 determines the distance D from which the generation source of the signal components WB, WC, and WD is received from the wave receiving unit 200 for each of the signal components WB, WC, and WD included in the reflected signal WS. It can be recognized how long these signal components WB, WC, WD exist. Here, it is known that the miscellaneous reflection signal component WD and the seafloor reflection signal component WB are continuously present at a substantially constant distance. On the other hand, it is known that the reflected signal component WB from the target exists at a specific time, and the distance D between the generation source of the reflected signal WB and the receiving unit 200 changes with time. From this, by analyzing the first reflected signal information from the relationship between the distance D and the time T, the presence of the reflected signal component WB, the seafloor reflected signal component WC and the miscellaneous reflected signal component WD from the target It is possible to know the relationship with the distance D from the receiving unit 200. Therefore, the signal detection apparatus 1000 can recognize the reflected signal component WB from the target separately from the seafloor reflected signal component WC and the miscellaneous reflected signal component WD. Thereby, the signal detection apparatus 1000 can prevent erroneously detecting a seabed reflection signal, which is a reflection signal of a sound wave from the seabed, as a reflection signal from a target.

  Further, the signal detection apparatus 1000 according to the first embodiment of the present invention includes a second reflected signal processing unit 320. The second reflected signal processing unit 320 is based on the reflected signal WS received by the wave receiving unit 200, between the generation source of the signal components WB, WC, and WD included in the reflected signal WS and the wave receiving unit 200. The distance D, the azimuth S of the source of each signal component WB, WC, WD included in the reflected signal WS with respect to the wave receiving unit 200, and each signal component WB, WC, WD included in the reflected signal WS 2nd reflection signal information which shows the relationship with the signal strength of is produced | generated.

  As described above, the second reflected signal information generated by the second reflected signal processing unit 320 includes the signal components WB, WC, and WD included in the reflected signal WS between the generation source and the receiving unit 200. The distance D, the azimuth S of the source of each signal component WB, WC, WD included in the reflected signal WS with respect to the wave receiving unit 200, and each signal component WB, WC, WD included in the reflected signal WS The relationship with the signal strength is included. Therefore, each reflection signal component WB, WC, WD included in the second reflection signal information is extracted corresponding to the distance D where the reflection signal WB from the target exists in the first reflection signal information. Thus, the direction of each reflected signal component WB, WC, WD from the target can be detected. However, it is not possible to identify whether each signal component included in the reflected signal WS is a component of the reflected signal WB from the target, a component of the seafloor reflected signal WC, or a component of the miscellaneous reflected signal WD. At this time, the signal detection apparatus 1000 collates the first reflected signal information and the second reflected signal information for the distance D where the reflected signal WB from the target exists in the first reflected signal information. Thus, by extracting each signal component WB, WC, WD, it is possible to detect the orientation of each reflected signal component WB from the target. That is, as described above, in the first reflection signal information, the miscellaneous reflection signal component WD and the seafloor reflection signal component WB are continuously present at a substantially constant distance, whereas the reflection signal component WB from the target is present. Exists at a specific time, and it is known that the distance D to the receiving unit 200 changes with time. Based on this characteristic, the reflected signal component WB from the target can be extracted from the first reflected signal information. Thereby, the distance D between the reflected signal component WB from the target and the wave receiving unit 200 is also found. And the signal component located in the same distance as the distance D between the generation source of the reflected signal WB extracted from the first reflected signal information and the wave receiving unit 200 is extracted from the second reflected signal information. Thereby, the direction S of the reflected signal WB from the target can be detected.

  Therefore, the signal detection apparatus 1000 recognizes in which direction the signal component WB from the target exists and at what distance D from the wave receiving unit 200 based on the first and second reflected signal information. be able to. Thereby, the signal detection apparatus 1000 does not erroneously detect a seabed reflection signal, which is a reflection signal of a sound wave from the seabed, as a reflection signal from the target object, and the distance to the target object. Can be detected.

  In addition, the signal detection apparatus 1000 according to the first embodiment of the present invention includes a first display unit 400. The first display unit 400 displays the first reflected signal information. Thereby, various information included in the first reflected signal is displayed and provided on the first display unit 400. As a result, the operator visually observes the distance D between the source of the signal components WB, WC, and WD included in the reflected signal WS and the receiving unit 200, and after the receiving unit 200 transmits the sound wave WA. The relationship between the elapsed time T and the signal intensity of each signal component WB, WC, WD included in the reflected signal WS can be recognized.

Further, the signal detection apparatus 1000 according to the first embodiment of the present invention includes the second display unit 5.
00. The second display unit 500 displays the second reflected signal information. Thereby, various information included in the second reflected signal is displayed and provided on the second display unit 500. As a result, the operator visually observes the distance D between the source of the signal components WB, WC, and WD included in the reflected signal WS and the receiving unit 200, and the reflection when the receiving unit 200 is used as a reference. It is possible to recognize the relationship between the azimuth S of the source of each signal component WB, WC, and WD included in the signal WS and the signal intensity of the reflected signal WS.

  The signal detection method according to the first embodiment of the present invention includes a sound wave transmission step, a reflection signal reception step, and a first reflection signal information generation step. In the sound wave transmission step, the sound wave WA is transmitted by the wave transmission unit 100. In the reflected signal receiving step, the reflected signal WS of the sound wave WA is received by the wave receiving unit 200. In the first reflected signal information generating step, the reflected signal WS is changed to the reflected signal WS based on the reflected signal WS received in the reflected signal receiving step. The distance D between the generation source of each signal component included and the wave receiving unit, the elapsed time T after the wave receiving unit 200 transmits the sound wave WA, and the signal intensity of each signal component included in the reflected signal WS First reflection signal information indicating the relationship is generated.

  This signal detection method substantially corresponds to the signal detection device described above. Therefore, even with this signal detection method, the same effects as those of the signal detection apparatus described above can be obtained.

<Second Embodiment>
The configuration of electronic apparatus 1000A according to the second embodiment of the present invention will be described with reference to the drawings.

  FIG. 8 is a diagram illustrating the configuration of the signal detection apparatus 1000A. In FIG. 8, constituent elements equivalent to those shown in FIGS. 1 to 7 are denoted by the same reference numerals as those shown in FIGS. 1 to 7.

  As shown in FIG. 1, the signal detection apparatus 1000 </ b> A includes a transmission unit 100, a reception unit 200, a signal processing unit 300 </ b> A, a first display unit 400, and a second display unit 500. Composed.

  Here, FIG. 1 and FIG. 8 are compared. In FIG. 1, the signal processing unit 300 includes a first reflected signal processing unit 310 and a second reflected signal processing unit 320. In contrast, in FIG. 8, the signal processing unit 300 </ b> A includes a target reflection signal extraction unit 330 in addition to the first reflection signal processing unit 310 and the second reflection signal processing unit 320. In this respect, they are different from each other.

  As shown in FIG. 8, the target reflection signal extraction unit 330 is connected to both the first reflection signal processing unit 310 and the second reflection signal processing unit 320.

  The target reflection signal extraction unit 330 extracts the reflection signal component WB from the target from the reflection signal WS based on the first reflection signal information generated by the first reflection signal processing unit 310.

  The second reflected signal processing unit 320 also includes the signal components WC and WD other than the reflected signal component WB extracted by the target reflected signal extracting unit 330 among the reflected signals WS received by the wave receiving unit 200. The second reflected signal information is generated except for.

  The configuration of the signal detection device 1000A has been described above.

  Next, the operation of the signal detection apparatus 1000A will be described. The manner in which the target is detected using the signal detection device 1000A is the same as in FIG. Therefore, the operation of the signal detection apparatus 1000A will be described as appropriate using FIG.

  Here, S901, S903, S905, S907, and S909 in FIG. 9 correspond to S301, S303, S305, S307, and S309 in FIG. However, the process of S907 is different from the process of S307 in that the second reflected signal information is generated excluding the reflected signal from the target, as will be described in detail below.

  As shown in FIGS. 2 and 9, first, the wave transmission unit 100 transmits and outputs the transmission sound wave WA from the side of the hull 2000 toward the water (S901). As shown in FIG. 2, the transmission sound wave WA propagates radially around the transmission unit 100 that is the transmission source. The transmitted sound wave WA is reflected after colliding with the target 3000 and the sea bottom 4000. As shown in FIG. 2, the reflected signal WB generated after colliding with the target 3000 propagates radially around the portion of the target 3000 where the transmission sound wave WA collides. Similarly, as shown in FIG. 2, the reflected signal WC generated after colliding with the seabed 4000 propagates radially around the portion of the seabed 4000 where the transmitted sound wave WA collided.

  Next, the wave receiving unit 200 receives the reflected signal WS (S903). Specifically, the wave receiving unit 200 includes a reflected signal component WB having the target 300 as a source, a reflected signal component WC having the sea bottom 4000 as a source, and noise other than the reflected signals WB and WC. The miscellaneous reflection signal WD is received. The wave receiving unit 200 outputs the reflected signal WS to the signal processing unit 300.

  Next, the first reflected signal processing unit 310 of the signal processing unit 300 performs beam phasing on the reflected signal WS received by the wave receiving unit 200, and generates first reflected signal information (S905). The first reflected signal information is the same information as the content shown in FIG. The first reflected signal processing unit 310 outputs the first reflected signal information to the target reflected signal extracting unit 330.

  Next, the target reflection signal extraction unit 330 extracts the reflection signal WB from the target among the reflection signals WS based on the first reflection signal information generated by the first reflection signal processing unit 310. (S906). Here, as described in the first embodiment, the components of the miscellaneous reflection signal WD and the seafloor reflection signal WB are continuously present at a substantially constant distance, whereas the reflection signal component WB from the target is It can be seen that the distance D with respect to the receiver 200 exists at a specific time and changes with time. Using this characteristic, the target reflection signal extraction unit 330 extracts the reflection signal WB from the target in distinction from the seabed reflection signal WC and the miscellaneous reflection signal WD. Then, the target reflection signal extraction unit 330 outputs the extraction result to the second reflection signal processing unit 320.

  Next, the second reflected signal processing unit 320 of the signal processing unit 300 performs beam phasing on the reflected signal WS received by the wave receiving unit 200, and signal components WC and WD other than the reflected signal WB from the target. The second reflected signal information is generated except for (S907). Further, the second reflected signal processing unit 320 outputs the second reflected signal information to the second display unit 500.

  FIG. 10 shows an example of the second reflected signal information. As shown in FIG. 10, the second reflected signal information includes a reflected signal WB from the target (a signal component excluding signal components WC and WD other than the reflected signal WB from the target in the reflected signal WS). ) Between the source D and the receiving unit 200, the direction S of the source of the reflected signal component WB when the receiving unit 200 is used as a reference, and the signal intensity of these reflected signals WB. include.

  Then, the first display unit 400 displays and provides the first reflected signal information, and the second display unit 500 displays and provides the second reflected signal information (S909).

  At this time, as shown in FIG. 10, only the reflected signal component WB from the target is displayed and provided on the second display unit 500 as information from which the seafloor reflected signal component WC and the miscellaneous reflected signal component WD are removed. The The worker visually observes the distance D between the source of the reflected signal WB from the target and the receiving unit 200 and the receiving unit 200 in a state where the seafloor reflected signal WC and the miscellaneous reflected signal component WD are removed. The relationship between the azimuth S of the generation source of the reflected signal WB and the signal strengths of the reflected signals WB and WD can be confirmed.

  As described above, the signal processing apparatus 1000A according to the second embodiment of the present invention further includes the target object signal extraction unit 330. The target reflection signal extraction unit 330 is a component having a target as a generation source in the reflection signal WS based on the first reflection signal information generated by the first reflection signal processing unit 310. The reflected signal WB from is extracted. The second reflected signal processing unit 320 is a reflected signal other than the reflected signal WB from the target extracted by the target reflected signal extracting unit 330 among the reflected signals WS received by the wave receiving unit 200. The second reflected signal information is generated by removing the components WC and WD.

  Accordingly, the second reflected signal processing unit 320 uses the second reflected signal as information including only the reflected signal component WB from the target as information from which the seafloor reflected signal component WC and the miscellaneous reflected signal component WD are removed. It can be generated as information. Therefore, the signal detection apparatus 1000 can prevent the seabed reflected signal, which is the reflected signal of the sound wave from the seabed, from being erroneously detected as the reflected signal from the target.

  The present invention has been described above based on the embodiment. The embodiment is an exemplification, and various modifications, increases / decreases, and combinations may be added to the above-described embodiments without departing from the gist of the present invention. It will be understood by those skilled in the art that modifications to which these changes, increases / decreases, and combinations are also within the scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Transmission part 200 Reception part 300 Signal processing part 300A Signal processing part 310 1st reflected signal processing part 320 2nd reflected signal processing part 330 Target object reflected signal extraction part 400 1st display part 500 2nd display Part 1000 Signal detection device 1000A Signal detection device

Claims (6)

A wave transmitter that transmits sound waves to the water,
A wave receiving unit that receives a reflected signal of the sound wave output by the wave transmitting unit;
Based on the reflected signal received by the wave receiving unit, the distance between the source of each signal component included in the reflected signal and the wave receiving unit, and after the wave transmitting unit transmits the sound wave A signal detection apparatus comprising: a first reflection signal processing unit that generates first reflection signal information indicating a relationship between an elapsed time and a signal intensity of each signal component included in the reflection signal.   Based on the reflected signal received by the wave receiving unit, the distance between the source of each signal component included in the reflected signal and the wave receiving unit, and the reflection when the wave receiving unit is used as a reference A second reflected signal processing unit that generates second reflected signal information indicating the relationship between the direction of the source of each signal component included in the signal and the signal intensity of each signal component included in the reflected signal; The signal detection device according to claim 1. A target reflection signal extraction unit that extracts a reflection signal component from a target among the reflection signals based on the first reflection signal information generated by the first reflection signal processing unit;
The second reflected signal processing unit extracts a signal component other than the reflected signal component from the target, extracted by the target reflected signal extracting unit, from the reflected signal received by the receiving unit. The signal detection apparatus according to claim 2, wherein the second reflected signal information is generated except for the above.   The signal detection apparatus of any one of Claims 1-3 provided with the 1st display part which displays the said 1st reflected signal information.   The signal detection device according to claim 2, further comprising a second display unit that displays the second reflected signal information. A sound wave transmission step of transmitting sound waves by the wave transmission unit;
A reflected signal receiving step of receiving the reflected signal of the sound wave by a receiving unit;
Based on the reflected signal received in the reflected signal receiving step, the distance between the source of each signal component included in the reflected signal and the receiving unit, and after the receiving unit transmits the sound wave A first reflected signal information generating step of generating first reflected signal information indicating a relationship between an elapsed time of the first time and a signal intensity of each signal component included in the reflected signal.