Patent Publication Number: US-11392125-B2

Title: Docking support device of marine vessel

Description:
INCORPORATION BY REFERENCE 
     The disclosure of Japanese Patent Application No. 2018-144674 filed on Aug. 1, 2018 including its specification, claims and drawings, is incorporated herein by reference in its entirety. 
     BACKGROUND 
     The present disclosure relates to a docking support device of a marine vessel. 
     For example, the technology described in JP-A-2003-276677 has been already known. In the technology of JP-A-2003-276677, a millimeter wave radar was attached to a marine vessel, and the distance from the marine vessel to a docking object, like a landing pier, was measured, and the marine vessel was auto-docked at a landing pier, based on the measured distance. 
     SUMMARY 
     Even so, in the situation where auto docking is employed to dock a marine vessel at a landing pier, millimeter wave radars have several issues in accurately measuring a relative distance and a relative angle between the marine vessel and the landing pier, such as, (1) an issue that there is variation in the measured distance, because the intensity of the reflection varies depending on the shape of an object, (2) an issue that the measurement of distances cannot be performed beyond the resolution limit of a millimeter wave radar device, (3) an issue that it is probable that the measurement of distances cannot be achieved due to the specular reflection, and (4) an issue that the accuracy in the measurement of distances is decreased by the mixing of reflections from a non-object body in the surrounding area. 
     Meanwhile, reflections from a buoy floating between a marine vessel and a landing pier, a stake or a pole protruding from the water surface, a person floating on the water surface, and the like are low in intensity, even if the relative distance between a marine vessel and a landing pier can be measured accurately with the use of a millimeter wave radar. The measurement of distances may fail with high probability, and thus, it is likely that those bodies cannot be detected as an obstacle. 
     Hence, desired is a docking support device of a marine vessel which is capable of enhancing the accuracy in the distance measurement of a docking object, and can determine whether docking at the docking object is achievable or not, by detecting an obstacle which lies in the surroundings of an own marine vessel. 
     A docking support device of a marine vessel according to the present disclosure includes a LiDAR which detects a distance of a body lying in the surroundings of an own marine vessel, with the use of a laser; a short range body detection sensor which has a detectable distance of the body shorter than that of the LiDAR; a docking object detection unit which detects a docking object, which is an object at which the own marine vessel is to dock, based on an output signal of the LiDAR; an obstacle detection unit which detects an obstacle in the surroundings of the own marine vessel, based on an output signal of the short range body detection sensor; and a docking determination unit which determines whether docking at the docking object is achievable or not, based on a detection result of the docking object and a detection result of the obstacle, and outputs a determination result. 
     The LiDAR, which is a sensor using a laser, can improve the resolution and the accuracy in the detection of distance. Because docking objects are detected based on the detection result of the LiDAR, the accuracy in the distance measurement of a docking object can be increased. Furthermore, the LiDAR detects a body which lies on a laser irradiated straight line, and measures the distance to the body. Accordingly, illumination with the laser is easy to irradiate relatively large docking objects, such as a quay wall and a landing pier, and the detection of those docking objects is easy to achieve. However, illumination with the laser is hard to irradiate relatively small obstacles, such as a buoy and a stake, and the detection of those obstacles is hard to achieve. Even if the radiation direction of the laser is scanned, it is likely that some obstacles may fail to be detected, when scanning with high angular resolution is not employed. Furthermore, even if scanning with high angular resolution is employed, rolling of an own marine vessel during the scanning operation produces an area which becomes out of the scanning range, and it is likely that some obstacles may fail to be detected. Then, in addition to the LiDAR, a short range body detection sensor which is designed for short range use only is provided, and the certainty in the detection of an obstacle can be improved. Moreover, it can be determined with a sufficient degree of accuracy whether docking at the docking object is achievable or not, based on the detection result of a docking object by the LiDAR and the detection result of an obstacle by the short range body detection sensor. Then, according to the docking support device of a marine vessel pertinent to the present disclosure, the accuracy in the distance measurement of a docking object can be enhanced. In addition, the docking support device detects obstacles which lie in the surrounding area of the own marine vessel and can determine whether docking at the docking object is achievable or not. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram for explaining the body detection in the surroundings of an own marine vessel, in accordance with Embodiment 1; 
         FIG. 2  is a block diagram of a docking support device of a marine vessel in accordance with Embodiment 1; 
         FIG. 3  is a hardware configuration diagram of the docking support device of the marine vessel in accordance with Embodiment 1; 
         FIG. 4  is a drawing for explaining a marine vessel coordinate system in accordance with Embodiment 1; 
         FIG. 5  is a drawing for explaining a LiDAR coordinate system in accordance with Embodiment 1; 
         FIG. 6  is a drawing for explaining a short range sensor coordinate system in accordance with Embodiment 1; 
         FIG. 7  is a drawing for explaining the informing of a determination result on the achievability of docking in accordance with Embodiment 1; and 
         FIG. 8  is a drawing for explaining the designation of a target docking point in accordance with Embodiment 1. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Embodiment 1 
     With reference to drawings, explanation will be made about a docking support device of a marine vessel  1  (hereinafter, referred to simply as a docking support device  1 ), in accordance with Embodiment 1. The docking support device  1  is provided with LiDARs  11  (Light Detection and Ranging) and short range body detection sensors  12 . In a top down view of the marine vessel,  FIG. 1  is a schematic diagram for explaining the body detection in the surroundings of the own marine vessel  13  by the LiDARs  11  and the short range body detection sensors  12 . In  FIG. 1 , body detection ranges of the respective sensors are shown with broken lines.  FIG. 2  is a schematic block diagram of the docking support device  1 , and  FIG. 3  is a hardware configuration diagram of the docking support device  1 . 
     1-1. LiDAR  11   
     The LiDAR  11  irradiates with a laser to measure the scattered light of the laser beam which illuminated a body, and detects a distance to the body. The LiDAR  11  outputs, toward the outside, information on the relative distance of a detected body from the LiDAR  11 , information on the relative angle of the detected body with regard to the LiDAR  11 , information on the detected intensity of the body, and others. The output signals of the LiDAR  11  are entered into the controller  30 . 
     In the present embodiment, a plurality of LiDARs  11  (eight sets in the present case,  11   a  to  11   h ) are provided. Each of the LiDARs  11  has a laser irradiation angular range of the horizontal direction (a detection angular range), which is a predetermined angular range. The LiDAR  11  is configured not to swing a laser in the horizontal direction. In the present embodiment, the LiDAR  11  is configured to swing a laser in the up and down direction just within a predetermined angular range (for example, 45 degrees), in order to improve the accuracy in the detection of a body against the rolling of the vessel and the locational shift of the body in the up and down direction. It is to be noted that the LiDAR  11  may be configured to swing reflected laser beams in the up and down direction, by rotating a mirror which reflects laser beams, or may be configured to swing laser beams in the up and down direction, by rotating a light emitter of the laser. 
     The LiDARs  11  are arranged so that each of them detects a body which exists in an angular range of the horizontal direction which is different from others in the surrounding area of the own marine vessel  13 . In the present embodiment, a plurality of LiDARs  11  are arranged around the own marine vessel  13  to provide a 360 degree field of view, keeping in-between an angle interval (an angle interval of about 45 degrees) in the horizontal direction, in order that the own marine vessel  13  can be covered with a 360 degree field of all around view. Because the LiDAR  11  provides a several degree of irradiation angular range (detection angular range) in the horizontal direction, a body which falls into the angular range between two adjoining LiDARs  11  cannot be detected. Accordingly, the detection angular ranges of a plurality of LiDARs  11  become discrete angles, which are arranged in the surrounding area of the own marine vessel  13 . 
     1-2. Short Range Body Detection Sensor  12   
     The short range body detection sensor  12  is a sensor which has a detectable distance of the body shorter than that of the LiDAR  11 , and detects the distance to a body lying in the surroundings of the own marine vessel  13 . In the present embodiment, the short range body detection sensor  12  employs a sonar sensor, which detects the distance of a body using ultrasonic waves. The short range body detection sensor  12  outputs, toward the outside, information on the relative distance of a detected body from the short range body detection sensor  12 , information on the relative angle of the detected body with regard to the short range body detection sensor  12 , information on the detected intensity of the body, and others. The output signals of the short range body detection sensor  12  are entered into the controller  30 . 
     In the present embodiment, a plurality of short range body detection sensors  12  (eight sets in the present case,  12   a  to  12   h ) are provided. Each of the short range body detection sensors  12  has a detection angular range of the horizontal direction, which is a predetermined angular range. The short range body detection sensor  12  (sonar sensor) is capable of detecting a body which exists within a range of conical shape, where ultrasonic waves are irradiated. The short range body detection sensor  12  (sonar sensor) has a detection angular range of the horizontal direction which is broader than that of the LiDAR  11 . 
     The short range body detection sensors  12  are arranged so that each of them detects a body which exists in an angular range of the horizontal direction which is different from others in the surrounding area of the own marine vessel  13 . In the present embodiment, a plurality of short range body detection sensors  12  are arranged around the own marine vessel  13  to provide a 360 degree field of view, keeping in-between an angle interval (an angle interval of about 45 degrees) in the horizontal direction, in order that the own marine vessel  13  can be covered with a 360 degree field of all around view. The short range body detection sensors  12  are arranged so that the detection angular ranges of two adjoining sensors overlap each other, and the detection angular ranges of a plurality of short range body detection sensors  12  build up a 360 degree field of view around the own marine vessel  13 . 
     1-3. Controller  30   
     The docking support device  1  is provided with a controller  30 . As shown in  FIG. 2 , the controller  30  is provided with control units, which include a docking object detection unit  31 , an obstacle detection unit  32 , a docking determination unit  33 , an automatic docking control unit  34 , a target docking point designation unit  35  and the like. Each function in the controller  30  is achieved by processing circuits which are provided in the controller  30 . To be more precise, as shown in  FIG. 3 , the controller  30  includes, as the processing circuits, an arithmetic processing unit  90  (computer) like a CPU (Central Processing Unit), storage devices  91  which exchange data with the arithmetic processing unit  90 , an input circuit  92  which inputs external signals to the arithmetic processing unit  90 , an output circuit  93  which outputs signals from the arithmetic processing unit  90  to the outside, and the like. 
     As the storage devices  91 , there are provided with a RAM (Random Access Memory) which is configured to be capable of reading out data from and writing them in the arithmetic processing unit  90 , a ROM (Read Only Memory) which is configured to be capable of reading out data from the arithmetic processing unit  90 , and the like. The input circuit  92  is connected to the LiDARs  11 , the short range body detection sensors  12 , a user input device  21 , etc., and is equipped with input ports which input these output signals into the arithmetic processing unit  90 , and the like. The output circuit  93  is connected to a display device  22 , a loudspeaker  23 , a steering device  24 , etc., and is equipped with output ports which output control signals from the arithmetic processing unit  90  to those devices, and others. 
     In addition, each function in each of the control units  31  to  35  and others, which are provided in the controller  30 , is achieved by the arithmetic processing unit  90 , which executes instructions from software (programs) stored in the storage devices  91 , like a ROM and others, and collaborates with other hardware devices of the controller  30 , such as the storage devices  91 , the input circuit  92 , the output circuit  93 , and the like. It is to be noted that setting data, including parameters of the coordinate conversion, which are used in each of the control units  31  to  35  and others, are stored, as a part of software (programs), in the storage devices  91 , like a ROM and others. Hereafter, each function in the controller  30  will be explained in detail. 
     The docking object detection unit  31  detects a docking object  15 , which is an object at which the own marine vessel  13  is to dock, based on the output signals of the LiDAR  11 . The obstacle detection unit  32  detects an obstacle  16  in the surroundings of the own marine vessel  13 , based on output signals of the short range body detection sensor  12 . Then, the docking determination unit  33  determines whether docking at the docking object  15  is achievable or not, based on the detection result of the docking object  15  and the detection result of the obstacle  16 , and outputs a determination result. 
     When an obstacle  16 , such as a buoy floating on the water surface, a stake or a pole protruding from the ocean surface, a person floating on the water surface, etc., lies between a docking object  15  and the own marine vessel  13 , docking at the docking object  15  cannot be achieved. The LiDAR  11  detects a body which lies on a laser irradiated straight line, and measures the distance to the body. For this reason, illumination with the laser is easy to irradiate relatively large docking objects  15 , such as a quay wall and a landing pier, and the detection of those docking objects  15  is easy to achieve. However, illumination with the laser is hard to irradiate relatively small obstacles  16 , such as a buoy and a stake, and the detection of those obstacles  16  is hard to achieve. Even if two dimensional or three dimensional scanning, in which radiation directions of the laser are scanned, is used, it is likely that failures may occur in the detection of obstacles  16 , when scanning with high angular resolution is not employed. Moreover, even if scanning with high angular resolution is employed, rolling of the own marine vessel during the scanning operation produces an area which is out of the scanning range, and it is likely that failures may occur in the detection of obstacles  16 . Then, in addition to the LiDAR  11 , the short range body detection sensor  12  which is designed for short range use only, is provided, and the certainty in the detection of an obstacle  16  can be enhanced. So, it becomes possible to determine with a sufficient degree of accuracy whether docking at the docking object  15  is achievable or not, based on the detection result of the docking object  15  by the LiDAR  11  and the detection result of the obstacle  16  by the short range body detection sensor  12 . 
     In the present embodiment, a sonar sensor is used as the short range body detection sensor  12 , and the sonar sensor detects a body which lies in the range of conical shape, where ultrasonic waves are irradiated, and measures the distance to the body. Accordingly, even if the own marine vessel  13  rolls, ultrasonic waves can be applied to relatively small obstacles  16 , such as a buoy and a stake, and thus, occurrence of failures in the detection of obstacles  16  can be reduced. 
     The docking object detection unit  31  informs a user of a determination result on the achievability of the docking, by way of an informing device, such as the display device  22 , the loudspeaker  23  and the like, and what is more, outputs the determination result to the automatic docking control unit  34 , which will be described below. For example, as shown in  FIG. 7 , in a top down view of the marine vessel, the docking object detection unit  31  displays on the display device  22  the own marine vessel  13 , detection ranges of the respective LiDARs  11  and the respective short range body detection sensors  12 , detected docking objects  15  and an obstacle  16 , and also displays a determination result on the achievability of the docking. When it is determined that docking is not achievable, the docking object detection unit  31  displays the obstacle  16 , which is recognized as the contributing factor, on the display device  22  in a highlighted manner. 
     The docking object detection unit  31  determines, from among the bodies which are detected by the LiDARs  11 , a body other than docking objects  15  (water surface, a structural object in the background of the docking object  15 , and the like), based on information including the relative distance and the relative angle of the body, the reflection intensity of the laser beam, and the like, and extracts a docking object  15 , and outputs information on the relative distance of the docking object  15  and the like. For example, the docking object detection unit  31  calculates, from among the bodies which are detected by the LiDARs  11 , a gravity center value or an average value of the relative distances of bodies, from which bodies other than the docking object  15  are excluded, as a relative distance of the docking object  15 . Or, the docking object detection unit  31  selects (implements filtering) a body with high reflection intensity from among the bodies, from which bodies other than the docking object  15  are excluded, and calculates as a relative distance of the docking object  15 . 
     The obstacle detection unit  32  determines, from among the bodies which are detected by the short range body detection sensor  12 , a body other than obstacles  16  (water surface and the like), based on information including the relative distance and the relative angle of the body, the reflection intensity of ultrasonic waves, and others, and extracts an obstacle  16 , and then, outputs information on the relative distance of the obstacle  16  and the like. 
     It is to be noted that docking objects  15 , which are detected by the LiDAR  11  and the docking object detection unit  31 , also contain an obstacle  16 , such as a buoy and a stake, and obstacles  16 , which are detected by the short range body detection sensor  12  and the obstacle detection unit  32 , also contain a docking object  15 . By the enhanced performance of a sensor or detection processing, the docking object detection unit  31  may exclude also an obstacle  16  from among the detected bodies to extract a docking object  15 , and the obstacle detection unit  32  may exclude also a docking object  15  from among the detected bodies to extract an obstacle  16 . 
     1-3-1. First Determination Method Based on Relative Distance 
     Next, explanation will be made about a first determination method for determining based on the relative distance between a docking object  15  and an obstacle  16 . The docking object detection unit  31  detects the relative distance of the docking object  15  to the own marine vessel  13 , based on the output signals of the LiDAR  11 . The obstacle detection unit  32  detects the relative distance of the obstacle  16  to the own marine vessel  13 , based on the output signals of the short range body detection sensor  12 . The docking determination unit  33  determines whether the obstacle  16  is present or not between the own marine vessel  13  and the docking object  15 , based on the relative distance of the docking object  15  and the relative distance of the obstacle  16 ; and determines that docking is not achievable, when the obstacle  16  is determined to be present there; and determines that docking is achievable, when the obstacle  16  is determined not to be present there. 
     According to the present configurations, it is possible to determine the difference between the docking object  15  and the obstacle  16  with a sufficient degree of accuracy based on information of the relative distance, and to determine whether docking at the docking object  15  is achievable or not with a sufficient degree of accuracy. For example, when the relative distance of an obstacle  16  by the short range body detection sensor  12  is shorter than the relative distance of a docking object  15  by the LiDAR  11 , the docking determination unit  33  determines that the obstacle  16  is present between the own marine vessel  13  and the docking object  15 , and further determines that docking is not achievable. In contrast, when the difference between the relative distance of an obstacle  16  by the short range body detection sensor  12  and the relative distance of a docking object  15  by the LiDAR  11  is within the range of a predetermined judgment distance, the docking determination unit  33  determines that the obstacle  16  which is detected by the short range body detection sensor  12  is a body identical with the docking object  15 , and further determines that docking is achievable. 
     In the case where a plurality of LiDARs  11  and a plurality of short range body detection sensors  12  are provided, like in the present embodiment, the docking determination unit  33  determines whether the obstacle  16  is present or not between the own marine vessel  13  and the docking object  15 , based on the relative distance of the docking object  15  and the relative distance of the obstacle  16 , by the LiDAR  11  and the short range body detection sensor  12 , whose detection angular ranges in the surrounding area of the own marine vessel  13  are associated with each other. For example, as shown in  FIG. 1 , because a first LiDAR  11   a  is associated with (is close to each other) the angular detection ranges of a first short range body detection sensor  12   a  and a second short range body detection sensor  12   b , the docking determination unit  33  determines whether the obstacle  16  is present or not between the own marine vessel  13  and the docking object  15 , based on the relative distance of the docking object  15  detected by the first LiDAR  11   a  and the relative distance of the obstacle  16  detected by the first short range body detection sensor  12   a  or the second short range body detection sensor  12   b . In the case where the obstacle  16  is determined to be present in any of associated relations, the docking determination unit  33  determines that docking is not achievable. 
     It is to be noted that the second LiDAR  11   b  is associated with the second short range body detection sensor  12   b  and the third short range body detection sensor  12   c , in the angular detection range. The eighth LiDAR  11   h  is associated with the eighth short range body detection sensor  12   h  and the first short range body detection sensor  12   a , in the angular detection range. With regard to other sensors, a LiDAR  11  and short range body detection sensors  12 , which have close angular detection ranges with each other, are in the associated relation. 
     1-3-2. Second Determination Method Based on Relative Distance and Relative Angle 
     Next, explanation will be made about a second determination method for determining based on the relative distances and the relative angles of a docking object  15  and an obstacle  16 . The docking object detection unit  31  calculates the relative distance and the relative angle of a docking object  15  to the own marine vessel  13 , based on the output signals of the LiDAR  11  and information on the body detection range of the LiDAR  11  to the own marine vessel  13 . The obstacle detection unit  32  calculates the relative distance and the relative angle of an obstacle  16  to the own marine vessel  13 , based on the output signals of the short range body detection sensor  12  and information on the body detection range of the short range body detection sensor  12  to the own marine vessel  13 . Then, the docking determination unit  33  determines whether the obstacle  16  is present or not between the own marine vessel  13  and the docking object  15 , based on the relative distance and the relative angle of the docking object  15  and the relative distance and the relative angle of the obstacle  16 . When the obstacle  16  is determined to be present there, the docking determination unit  33  determines that docking is not achievable, and when the obstacle  16  is determined not to be present there, the docking determination unit  33  determines that docking is achievable. 
     According to the present configurations, it is possible to determine relative positional relationships to the own marine vessel  13 , regarding the docking object  15  and the obstacle  16 , with a more sufficient degree of accuracy, and to determine whether docking at the docking object  15  is achievable or not, with a sufficient degree of accuracy. 
     Hereinafter, explanation will be made in detail about the relative distance and the relative angle to the own marine vessel  13 .  FIG. 4  shows a marine vessel coordinate system, which represents a coordinate system to the own marine vessel  13 . Assuming that Zb axis is a going straight direction of the own marine vessel  13 , Xb axis of a right and left direction and Yb axis of an up and down direction can be defined using the left handed system. A part of the coordinate of a docking object  15  at a certain time T=t in the marine vessel coordinate system can be represented as (xbp (t), ybp (t), zbp (t)). 
     A LiDAR coordinate system, which represents a coordinate system to each of the LiDARs  11 , is shown in  FIG. 5 . Assuming that Zr axis is a direction of scanning center angle, Xr axis and Yr axis can be defined using the left handed system. A part of the coordinate of a docking object  15  at a certain time T=t in the LiDAR coordinate system can be represented as (xrp (t), yrp (t), zrp (t)). 
     A short range sensor coordinate system, which represents a coordinate system to each of the short range body detection sensors  12 , is shown in  FIG. 6 . Assuming that the Zo axis is a direction of the center angle in the detection range, the Xo axis and the Yo axis can be defined using the left handed system. A part of the coordinate of an obstacle  16  at a certain time T=t in the short range sensor coordinate system can be represented as (xop (t), yop (t), zop (t)). 
     The docking object detection unit  31  calculates a coordinate (xbp (t), ybp (t), zbp (t)) of the docking object  15  in the LiDAR coordinate system, based on the output signals of the LiDAR  11 . 
     Furthermore, by applying rotation and parallel translation to a coordinate in the LiDAR coordinate system with the use of predetermined parameters (r11r, r12r . . . , t1r, t2r, t3r) of the coordinate conversion, the docking object detection unit  31  converts the coordinate (xrp (t), yrp (t), zrp (t)) of an docking object  15  in the LiDAR coordinate system into the coordinate (xbp (t), ybp (t), zbp (t)) of the docking object  15  in the marine vessel coordinate system, as shown in the next equation. The parameters of the coordinate conversion are each predetermined from the relative relations between the LiDAR coordinate system and the marine vessel coordinate system, based on information including mounting locations and angles of the LiDARs  11  in the own marine vessel  13 . It is to be noted that, for the sake of simplicity in the explanation, Equation (1) denotes, as a representative case, the coordinate conversion in which coordinates of one LiDAR  11  and one docking object  15  are dealt with. However, the coordinates of a plurality of LiDARs  11  and a plurality of docking objects  15  are each subjected to the processing of the coordinate conversion, and the respective parameters of the coordinate conversion are set in each of the plurality of LiDARs  11 . 
     
       
         
           
             
               
                 
                   
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     The obstacle detection unit  32  calculates a coordinate (xop (t), yop (t), zop (t)) of the obstacle  16  in the short range sensor coordinate system, based on the output signals of the short range body detection sensor  12 . 
     In addition, by applying rotation and parallel translation to a coordinate in the short range sensor coordinate system with the use of predetermined parameters (r11o, r12o . . . , t1o, t2o, t3o) of the coordinate conversion, the obstacle detection unit  32  converts the coordinate (xop (t), yop (t), zop (t)) of an obstacle  16  in the short range sensor coordinate system into the coordinate (xbp (t), ybp (t), zbp (t)) of the obstacle  16  in the marine vessel coordinate system. The parameters of the coordinate conversion are each predetermined from the relative relations between the short range sensor coordinate system and the marine vessel coordinate system, based on information including mounting locations and angles of the short range body detection sensors  12  in the own marine vessel  13 . It is to be noted that, for the sake of simplicity in the explanation, Equation (2) denotes, as a representative case, the coordinate conversion in which coordinates of one short range body detection sensor  12  and one obstacle  16  are dealt with. However, the coordinates of a plurality of short range body detection sensors  12  and a plurality of obstacles  16  are each subjected to the processing of the coordinate conversion, and the respective parameters of the coordinate conversion are set in each of the plurality of short range body detection sensors  12 . 
     
       
         
           
             
               
                 
                   
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     As shown in  FIG. 1 ,  FIG. 7 , and  FIG. 8 , the docking determination unit  33  calculates a boundary line  17  of the docking objects  15  in the marine vessel coordinate system, by connecting the coordinates of two docking objects  15  which are closely located each other. In the present embodiment, the docking determination unit  33  calculates a boundary line  17  of the docking objects  15  at the own marine vessel  13  side, by connecting the coordinates, in the marine vessel coordinate system, of two docking objects  15 , which are detected by two neighboring LiDARs  11  arranged in the surrounding area of the own marine vessel  13 . The docking determination unit  33  may not only create the connection between the two coordinates at the end points of the boundary line  17 , but also extend a straight line toward an outer side of the two coordinates. Further, the docking determination unit  33  may calculate a relative angle between the travelling direction (Zb axis) of the own marine vessel  13  and the boundary line  17  connecting the two docking objects  15 . 
     Then, in the marine vessel coordinate system, the docking determination unit  33  determines that docking is not achievable, when the coordinate of the obstacle  16  is present in a region between the boundary line  17  of the docking objects  15  and the own marine vessel  13 , and determines that docking is achievable, when the coordinate of the obstacle  16  is not present there. 
     It is to be noted that the own marine vessel  13  is located near the original point of the marine vessel coordinate system. The docking determination unit  33  may determine whether the coordinate of the obstacle  16  is present or not in a region between the boundary line  17  of the docking objects  15  and the outline of the own marine vessel  13 , using predetermined coordinate information on the outline of the own marine vessel  13 . For example, the docking determination unit  33  determines whether the coordinate of the obstacle  16  is present or not in a region sandwiched between the boundary line  17  of the docking objects  15  and the outline of the own marine vessel  13 , when viewed in the Yb axis direction of the marine vessel coordinate system (the up and down direction of the marine vessel). 
     1-3-3. Target Docking Point Designation Unit  35   
     The target docking point designation unit  35  accepts, from a user, the designation to designate a target docking point at which docking is actually to be performed, from among docking objects  15  which are detected by the docking object detection unit  31 . The target docking point designation unit  35  displays the detected docking objects  15  on the display device  22 , and sets, as a target docking point, a point or an area which is designated by the user via the user input device  21 , from among the docking objects  15  which are shown by a point or a line. For example, as shown in  FIG. 8 , the target docking point designation unit  35  displays, in a top down view of the marine vessel, on the display device  22 , the own marine vessel  13 , the detected positions of each docking object  15 , and the boundary line  17  connecting the two docking objects  15 , and accepts the selection from the user. 
     The docking determination unit  33  determines whether the obstacle  16  is present or not between the own marine vessel  13  and the target docking point, and determines whether docking is achievable or not, depending on the presence or absence of the obstacle  16 . According to the present configurations, it becomes possible to determine whether the obstacle  16  is present or not between the target docking point and the own marine vessel  13 , even in a case where the surroundings of the own marine vessel  13  is enclosed by quay walls, and obstacles  16  which lie between docking objects  15  other than the target docking point and the own marine vessel  13  can be excluded from the determination in the achievability of docking. Accordingly, determination fitting for the user&#39;s purpose can be performed. 
     1-3-4. Automatic Docking Control Unit  34   
     In order to achieve the docking at a docking object  15 , the automatic docking control unit  34  performs automatic docking control, which drives a marine vessel in an automatic steering mode. By carrying out the control of steering and driving force, the automatic docking control unit  34  drives the marine vessel to dock at a docking object  15 , with the designated side face of the marine vessel directing to the docking object (left hand side docking, right hand side docking, rear docking, front docking, and the like). The automatic docking control unit  34  transmits a steering command value and a driving force command value, to the steering device  24 , which makes adjustments in the steering and the driving force. The automatic docking control unit  34  receives positional information on the docking object  15  and the obstacle  16  from the docking determination unit  33 , and performs automatic steering of the marine vessel, using the positional information on the docking object  15  (relative distance, relative angle, and the like, between the docking object  15  and the own marine vessel  13 ). In the case where a target docking point is designated by the target docking point designation unit  35 , the automatic docking control unit  34  performs, in the automatic docking control, automatic steering of the marine vessel, in order to achieve the docking at the target docking point. 
     The automatic docking control unit  34  performs the automatic docking control, in the case where it is determined by the docking determination unit  33  that docking is achievable, and ceases the automatic docking control, in the case where it is determined by the docking determination unit  33  that docking is not achievable. Furthermore, the automatic docking control unit  34  may perform automatic steering of the marine vessel, in such a way that the marine vessel keeps away from the detected obstacle  16 , with a separation larger than a predetermined distance. 
     Other Embodiments 
     Lastly, other embodiments of the present disclosure will be explained. Each of the configurations of embodiments to be explained below is not limited to be separately utilized, but can be utilized in combination with the configurations of other embodiments, as long as no discrepancy occurs. 
     (1) In the above mentioned Embodiment 1, a case in which the short range body detection sensor  12  employs a sonar sensor has been explained as an example. However, embodiments of the present disclosure are not limited to the foregoing case. That is to say, the short range body detection sensor  12  can employ any other sensor than a sonar sensor, as long as the sensor has a detectable distance of the body which is shorter than that of the LiDAR  11 . For example, the short range body detection sensor may be a camera sensor which detects the distance to a body with the use of a picture image which is image pick-upped with a camera. 
     (2) In the above mentioned Embodiment 1, a case in which the target docking point designation unit  35  and the automatic docking control unit  34  are provided has been explained as an example. However, embodiments of the present disclosure are not limited to the foregoing case. That is to say, the automatic docking control unit  34  is not provided, and the docking determination unit  33  may only inform a user of a determination result on the achievability of docking, via an informing device. 
     (3) In the above mentioned Embodiment 1, a case in which the LiDAR  11  swings a laser in the up and down direction, and does not swing it in the horizontal direction has been explained as an example. However, embodiments of the present disclosure are not limited to the foregoing case. That is to say, the LiDAR  11  may be configured to swing a laser in the horizontal direction, or may be configured not to swing a laser at all. 
     (4) In the above mentioned Embodiment 1, a case in which the LiDARs  11  and the short range body detection sensors  12  are arranged around the own marine vessel  13  to provide a 360 degree field of view has been explained as an example. However, embodiments of the present disclosure are not limited to the foregoing case. That is to say, with regard to the arrangement of LiDARs  11  and short range body detection sensors  12 , the LiDARs  11  and the short range body detection sensors  12  may be provided only on a lateral side (for example, the port side only) of the own marine vessel which is to perform docking, in the case where the own marine vessel has a limited lateral face of the docking (for example, the port side face only). 
     (5) In the above mentioned Embodiment 1, a case in which the controller  30  is provided with the control units  31  to  35  and others has been explained, as an example. However, embodiments of the present disclosure are not limited to the foregoing case. That is to say, each of the control units  31  to  35  is distributed among a plurality of controllers, and the plurality of controllers may be configured to make communications with each other. For example, a case is allowed where the control units  31  to  33  and  35  are provided in one controller, and the automatic docking control unit  34  is provided in another controller. 
     Although the present disclosure is described above in terms of an exemplary embodiment, it should be understood that the various features, aspects and functionality described in the embodiment are not limited in their applicability to the particular embodiment with which they are described, but instead can be applied, alone or in various combinations to the embodiment. It is therefore understood that numerous modifications which have not been exemplified can be devised without departing from the scope of the present disclosure. For example, at least one of the constituent components may be modified, added, or eliminated.