JP7165392B2 - plotter - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plotter mounted on a ship for displaying the position and orientation of the own ship.

2. Description of the Related Art There is a plotter that is installed on a ship and uses GPS (Global Positioning System) to display the position of the own ship on the sea. This plotter displays the position of the own ship on the sea based on the radio waves received by the GPS antenna.

A plotter using a magnetic compass in addition to GPS is also known (for example, Patent Document 1). By setting the reference position of the magnetic compass to match the direction of the bow, the plotter displays the direction of the bow based on the direction indicated by the magnetic compass.

Japanese Patent Application Laid-Open No. 2001-183160

However, it was difficult to accurately set the reference position of the magnetic compass to match the direction of the bow of the ship, which could have caused an error between the compass direction indicated by the magnetic compass and the actual direction of the bow. In addition, the magnetic compass can cause errors due to the installation location, magnetic substances around the magnetic compass, individual differences in the magnetic compass, etc., so it is necessary to correct the error each time, which is troublesome for the user. I had a problem.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a plotter that saves the user the trouble of correcting errors in the magnetic compass.

In order to achieve this object, the plotter according to claim 1 comprises position information acquisition means for acquiring position information based on radio waves from a satellite, and a magnetic compass mounted on a ship for outputting a compass azimuth determined based on geomagnetism. compass azimuth acquisition means for acquiring the compass azimuth angle transmitted by; and displaying the position of the ship based on the position information acquired by the position information acquisition means and acquired by the compass azimuth acquisition means. display means for displaying the orientation of the ship based on the compass azimuth angle, the movement azimuth acquisition means for acquiring the movement azimuth angle obtained from the temporal change of the position information; When a period in which the movement speed of the ship is equal to or higher than a predetermined speed continues for a predetermined period, the moving azimuth obtained by the moving azimuth obtaining means and the compass azimuth obtaining means during the predetermined period. a coefficient obtaining means for obtaining a correction coefficient used for correcting the compass azimuth angle based on the compass azimuth angle; a storage means for storing the coefficient obtained by the coefficient obtaining means; correction means for correcting the compass azimuth based on the coefficient stored by the coefficient acquisition means, if the moving speed of the ship is equal to or higher than the predetermined speed even after acquiring the coefficient, Acquisition of the new coefficients is set to non-execution .

The plotter according to claim 2 comprises position information acquisition means for acquiring position information based on radio waves from satellites, and said compass direction transmitted by a magnetic compass mounted on a ship for outputting a compass direction angle determined based on geomagnetism. a compass azimuth obtaining means for obtaining an angle; displaying the position of the ship based on the position information obtained by the position information obtaining means; display means for displaying the direction of the ship by means of a moving azimuth angle obtaining means for obtaining a moving azimuth angle obtained from the temporal change of the position information; based on the moving azimuth obtained by the moving azimuth obtaining means and the compass azimuth obtained by the compass azimuth obtaining means during the predetermined period when the above period continues for a predetermined period a coefficient acquiring means for acquiring a coefficient for correction used for compensating the compass azimuth, a storage means for storing the coefficient acquired by the coefficient acquiring means, and the coefficient stored by the storage means; correction means for correcting the compass azimuth angle according to the compass azimuth angle based on the compass azimuth angle, and the coefficient acquisition means acquires the coefficient when the difference between the maximum value and the minimum value of the compass azimuth angle is within a predetermined range for a specific period or longer. do.

The plotter according to claim 3 comprises position information acquisition means for acquiring position information based on radio waves from satellites, and said compass direction transmitted by a magnetic compass mounted on a ship and outputting a compass direction angle determined based on geomagnetism. a compass azimuth obtaining means for obtaining an angle; displaying the position of the ship based on the position information obtained by the position information obtaining means; and display means for displaying the direction of the ship, wherein all directions centered on the hull of the ship are divided into a plurality of areas, and the compass azimuth obtained by the compass azimuth acquisition means is displayed. moving azimuth obtaining means for obtaining a moving azimuth obtained from the temporal change of the position information; movement of the ship When a period in which the velocity is equal to or higher than a predetermined speed continues for a predetermined period, the moving azimuth obtained by the moving azimuth obtaining means and the compass azimuth obtained by the compass azimuth obtaining means during the predetermined period. a coefficient acquiring means for acquiring a correction coefficient used for correcting the compass azimuth angle in the area determined by the area determining means to be directed by the ship based on the angle and the coefficient acquiring means; storage means for storing the coefficient acquired by each region; correction means for correcting the compass azimuth angle based on the coefficient stored by the storage means; when the coefficient is newly acquired, comparing means for comparing the coefficient already stored in the area with the newly obtained coefficient; If the difference between the coefficient and the newly obtained coefficient is within a specific range, the already stored coefficient is deleted from the storage means, and the newly obtained coefficient is stored as the coefficient of the region. and when the difference between the coefficient already stored in the area and the newly obtained coefficient is not within a specific range, the coefficients of all the areas already stored from the storage means.

The plotter according to claim 4 comprises position information acquisition means for acquiring position information based on radio waves from satellites, and said compass direction transmitted by a magnetic compass mounted on a ship and outputting a compass direction angle determined based on geomagnetism. a compass azimuth obtaining means for obtaining an angle; displaying the position of the ship based on the position information obtained by the position information obtaining means; and display means for displaying the direction of the ship, wherein all directions centered on the hull of the ship are divided into a plurality of areas, and the compass azimuth obtained by the compass azimuth acquisition means is displayed. moving azimuth obtaining means for obtaining a moving azimuth obtained from the temporal change of the position information; movement of the ship When a period in which the velocity is equal to or higher than a predetermined speed continues for a predetermined period, the moving azimuth obtained by the moving azimuth obtaining means and the compass azimuth obtained by the compass azimuth obtaining means during the predetermined period. a coefficient acquiring means for acquiring a correction coefficient used for correcting the compass azimuth angle in the area determined by the area determining means to be directed by the ship based on the angle and the coefficient acquiring means; storage means for storing the coefficient obtained by each region; and correction means for correcting the compass azimuth based on the coefficient stored by the storage means, stored in the storage means The coefficient for each region is the coefficient obtained in one orientation included in the region, and the plotter stores the coefficient of the first region and the coefficient of the second region stored by the storage means. interpolation means for interpolating the coefficients and obtaining the coefficients in a direction sandwiched between the direction in which the coefficients of the first region are obtained and the direction in which the coefficients of the second region are obtained; interpolating storage means for storing, for each direction, the coefficients in directions interposed between the direction from which the coefficients of the first region and the direction from which the coefficients of the second region are obtained.
A plotter according to claim 5 is the plotter according to any one of claims 1 to 4, wherein the coefficient obtaining means calculates the moving azimuth angle at the same time during the predetermined period during which the ship moves at the predetermined speed or more. and the compass azimuth angle, and the coefficient is obtained by averaging the differences at each time during the predetermined period.
A plotter according to claim 6 is the plotter according to any one of claims 1 to 5, wherein the coefficient acquisition means is configured to obtain Get the coefficients.
A plotter according to claim 7 is the plotter according to any one of claims 1 to 6, wherein the coefficient acquisition means is configured to obtain the Get coefficients.

According to the plotter of the present invention , position information based on radio waves from satellites is obtained by the position information obtaining means. Compass azimuth angle acquisition means acquires a compass azimuth angle transmitted by a magnetic compass mounted on a ship and outputting a compass azimuth angle determined based on geomagnetism. The display means displays the position of the ship based on the position information acquired by the position information acquisition means, and displays the orientation of the ship based on the compass azimuth acquired by the compass azimuth acquisition means. Further, the moving azimuth obtained by the temporal change of the position information is obtained by the moving azimuth obtaining means. Then, when a period in which the moving speed of the ship is equal to or higher than a predetermined speed continues for a predetermined period, the moving azimuth obtained by the moving azimuth obtaining means and the compass azimuth obtained by the compass azimuth obtaining means during the predetermined period. A correction coefficient used for correcting the compass azimuth angle is obtained by the coefficient obtaining means. The coefficients acquired by the coefficient acquisition means are stored by the storage means, and the compass azimuth angle is corrected by the correction means based on the coefficients stored by the storage means.

Here, when a period in which the movement speed of the ship is equal to or higher than a predetermined speed continues for a predetermined period of time, the hull sails in a stable attitude. At this time, the moving azimuth of the ship is the azimuth of the actual direction of the ship. The plotter according to claim 1 is used to correct the compass azimuth angle based on the movement azimuth angle and the compass azimuth angle when the period in which the moving speed of the ship is equal to or higher than a predetermined speed continues for a predetermined period of time. Therefore, the user can correct the compass azimuth simply by sailing the ship at a speed equal to or higher than a predetermined speed for a predetermined period of time. Therefore, there is an effect that the user can save the trouble of correcting the compass azimuth error.

And according to the plotter of Claim 1 , there exist the following effects. That is, if the moving speed of the ship is equal to or higher than the predetermined speed even after obtaining the coefficients, the coefficient obtaining means does not execute the obtaining of new coefficients. While the hull is sailing in a stable attitude at a speed equal to or higher than the predetermined speed, the difference between the movement azimuth angle and the compass azimuth angle does not change significantly. Therefore, it is unlikely that the coefficient will change while the hull is sailing in a stable attitude at a speed equal to or higher than the predetermined speed. As a result, it is possible to prevent the coefficients from being acquired many times even though the coefficients have not changed.

Moreover, according to the plotter of Claim 2 , there exist the following effects. That is, when the difference between the maximum value and the minimum value of the compass azimuth angle is within a predetermined range for a specific period or longer, the coefficient is obtained by the coefficient obtaining means. When the moving speed of the ship is equal to or higher than a predetermined speed and the difference between the maximum value and the minimum value of the compass azimuth angle is within a predetermined range, the hull travels straight in a stable attitude. By acquiring the coefficients in this state, it is possible to reduce correction errors due to variations in the compass azimuth angle. As a result, there is an effect that the accuracy of correction can be improved.

Moreover, according to the plotter of Claim 3 , there exist the following effects. That is, all directions centered on the hull of the ship are divided into a plurality of areas, and an area including the azimuth angle to which the ship is facing is determined by the area determining means based on the compass azimuth angle obtained by the compass azimuth obtaining means. be done. The coefficient acquisition means acquires the coefficient in the area determined by the area determination means that the ship is headed. The storage means stores the coefficients for each region. Thereby, correction can be performed using a different coefficient for each region. Therefore, even if the error differs due to the difference in orientation, there is an effect that the optimum coefficient can be set for each region.

In addition, when a coefficient is newly obtained in the area of 1 by the coefficient obtaining means, the coefficient already stored in the area and the newly obtained coefficient are compared by the comparing means. If the difference between the already stored coefficient and the newly obtained coefficient is within a specific range, the already stored coefficient is deleted from the storage means and the newly obtained coefficient is used for the area. It is stored in the storage means as a coefficient. If the difference between the already stored coefficients and the newly obtained coefficients is not within the specified range, the already stored coefficients of all regions are deleted from the storage means.

As a result, when new coefficients that are significantly different from the already stored coefficients are obtained due to a large change in the installation situation of the magnetic compass, etc., the coefficients of all regions can be deleted. Therefore, it is possible to prevent the use of coefficients with large errors. Therefore, there is an effect that it is possible to prevent erroneous information from being displayed to the user.

According to the plotter of claim 4 , the following effects can be obtained. That is, all directions centered on the hull of the ship are divided into a plurality of areas, and an area including the azimuth angle to which the ship is facing is determined by the area determining means based on the compass azimuth angle obtained by the compass azimuth obtaining means. be done. The coefficient acquisition means acquires the coefficient in the area determined by the area determination means that the ship is headed. The storage means stores the coefficients for each region. Thereby, correction can be performed using a different coefficient for each region. Therefore, even if the error differs due to the difference in orientation, there is an effect that the optimum coefficient can be set for each region. In addition, the coefficients for each region stored in the storage means are the coefficients obtained in one orientation included in the region. The coefficients of the first region and the coefficients of the second region stored by the storage means are interpolated by the interpolating means, and the direction from which the coefficients of the first region are obtained and the direction from which the coefficients of the second region are obtained are changed. Coefficients in the pinched orientation are obtained. Coefficients in directions interposed between the directions from which the coefficients of the first region obtained by the interpolating means are obtained and the directions from which the coefficients of the second region are obtained are stored by the interpolation storage means for each direction. As a result, even if the ship does not sail in all directions, it is possible to obtain coefficients suitable for the direction sandwiched between the direction from which the coefficients of the first region are obtained and the direction from which the coefficients of the second region are obtained. There is an effect that it can be corrected using
According to the plotter of claim 5, in addition to the effects of the plotter of any one of claims 1 to 4, the following effects are achieved. That is, the coefficient obtaining means obtains a plurality of differences between the moving azimuth angle and the compass azimuth angle at the same time during a predetermined period in which the ship moves at a predetermined speed or higher. A coefficient is obtained by the coefficient obtaining means by averaging the difference at each time during the predetermined period. Thus, a coefficient can be obtained based on a plurality of moving azimuth angles and compass azimuth angles during a predetermined period of time. Therefore, it is possible to reduce correction errors caused by variations in the moving azimuth angle and the compass azimuth angle at each time. Therefore, there is an effect that the accuracy of correction can be improved.
According to the plotter of claim 6, in addition to the effects of the plotter of any one of claims 1 to 5, the following effects are obtained. That is, the coefficient is obtained by the coefficient obtaining means when the moving speed of the ship changes from a state lower than a predetermined speed to a predetermined speed or higher. As a result, since it is during acceleration that the moving speed of the ship changes from a state lower than the predetermined speed to the predetermined speed or higher, there is an effect that it is possible to avoid obtaining a correction value during deceleration when the hull attitude is unstable.
According to the plotter of claim 7, in addition to the effects of the plotter of any one of claims 1 to 6, the following effects are obtained. That is, the coefficient is obtained by the coefficient obtaining means when the moving speed of the ship first reaches or exceeds the predetermined speed after the power is turned on. As a result, a new coefficient can be obtained each time the power is turned on. If the power is turned on, it is possible that the plotter has not been used for a while, and it is highly possible that the environment around the magnetic compass has changed. Since the plotter according to claim 6 can obtain new coefficients after the power is turned on, it has the effect of being able to cope with such a change in error before the power is turned on.

1 is a schematic diagram showing the configuration of a plotter according to a first embodiment of the present invention; FIG. FIG. 4 is a schematic side view showing a state in which position information and orientation information of the own ship are acquired by a ship equipped with a plotter. 3 is a block diagram showing the electrical configuration of the plotter; FIG. FIG. 4 is a schematic diagram showing timings for acquiring correction value data; 4 is a flow chart showing movement azimuth acquisition processing executed in the control device. 4 is a flowchart showing compass azimuth acquisition processing executed in the control device. 4 is a flowchart showing correction value calculation processing executed in the control device; 4 is a flowchart showing correction processing executed in the control device; FIG. 11 is a schematic diagram showing an outline of plotter correction according to the second embodiment; 3 is a block diagram showing the electrical configuration of the plotter; FIG. (a) is a schematic diagram of an area correction table stored in a flash memory, and (b) is a schematic diagram of an omnidirectional correction table stored in a RAM. 4 is a flow chart showing an area correction table generation process executed by the control device; 4 is a flowchart showing omnidirectional correction table generation processing executed by the control device; 4 is a flowchart showing omnidirectional correction processing executed by the control device;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. First, an outline of a plotter 12 according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing the configuration of the plotter 12. As shown in FIG. FIG. 2 is a schematic side view showing a state in which the ship 11 on which the plotter 12 is mounted acquires the position information and direction information of the own ship.

The plotter 12 is a device that displays the sea position and orientation (bow orientation) of the ship 11 on the display device 16 . The configuration will be described below. As shown in FIG. 1, the plotter 12 has a body 13 . The main body 13 is configured to be electrically connectable to the magnetic compass 14 and the GPS antenna 15 respectively by cables. The magnetic compass 14 and the GPS antenna 15 may be configured inseparably from the main body 13 from the beginning, or may be configured to be connected to the main body 13 later.

The magnetic compass 14 is a device that is fixed to the ship 11 and measures a compass azimuth angle C that is an azimuth angle determined based on geomagnetism. By aligning the reference position of the magnetic compass 14 with the bow direction of the ship 11, the azimuth angle to which the bow of the ship 11 is directed can be recognized from the compass azimuth angle C. However, the compass azimuth angle C includes an error E due to a deviation when the magnetic compass 14 is installed with the reference position aligned with the bow direction, installation location, surrounding magnetic materials, individual differences in the compass itself, geomagnetism, and the like. Therefore, the true azimuth angle T, which is the azimuth angle of the true azimuth, is given by the following equation (1).

T=CE (1)
That is, by subtracting the error E from the compass azimuth C, the true azimuth T can be obtained. In other words, the error E can be obtained by subtracting the true azimuth angle T from the compass azimuth angle C.

Azimuth angles are measured from 0° to 360° eastward with true north at 0°. For example, when the ship 11 faces due south of the compass direction, the compass direction angle C is 180°. On the other hand, when an error E of 2° is included, the true azimuth angle T is 178° according to the following equation (2).

T=180°-2° (2)

The GPS antenna 15 is an antenna that receives signals transmitted from a plurality of GPS satellites S and transmits position information (latitude, longitude, speed, etc.) and moving direction of the ship 11 to the main body 13 based on the received signals. The direction of movement is determined by the GPS antenna 15 based on temporal changes in latitude and longitude.

The main body 13 has a display device 16 and operation buttons 17 . The display device 16 is a device for displaying a map 16b of the sea and a vessel mark 16a indicating the position and direction of the vessel 11. FIG. The ship mark 16a is a figure that imitates the ship 11 . The ship mark 16a is displayed at the current position (latitude and longitude) of the ship 11 on the marine map 16b. Also, the vessel mark 16 a is displayed on the display device 16 so that the direction of the bow changes depending on the direction of the vessel 11 .

The display device 16 also displays an orientation mark 16c and a latitude/longitude display 16d. The azimuth mark 16c is a figure for displaying the azimuth of the sea map 16b. The latitude and longitude display 16d displays the latitude and longitude of the ship 11's current location. The user can recognize the direction in which the ship 11 is facing by looking at the direction mark 16c and the direction of the ship mark 16a on the display device 16. FIG.

The operation button 17 is a button for receiving input from the user.

Next, the electrical configuration of plotter 12 will be described with reference to FIG. FIG. 3 is a block diagram showing the electrical configuration of the plotter 12. As shown in FIG. The plotter 12 has a control device 20 inside the main body 13 . The control device 20 controls the operation of the plotter 12, for example, acquires information on the compass azimuth angle C based on the signal from the magnetic compass 14, and determines the position of the ship 11 based on the signal from the GPS antenna 15. Information (latitude, longitude, speed, etc.) and moving direction are acquired, and control is performed to display the position and orientation (bow direction) of the ship 11 on the display device 16 using the ship mark 16a on the sea map 16b. The control device 20 includes a CPU (Central Processing Unit) 21, a flash memory 22, a RAM (Random Access Memory) 23, a display controller 24, a VRAM (Video RAM) 25, and a GPS interface circuit (hereinafter "GPS I/ F”) 26 and an input port 27 .

A flash memory 22, a RAM 23, a display controller 24, a GPS I/F 26, and an input port 27 are connected to the CPU 21, and an operation button 17 (see FIG. 1) is connected from the outside of the control device 20. FIG. The display controller 24 is connected to the VRAM 25 and the display device 16 (see FIG. 1), the GPS I/F 26 is connected to the GPS antenna 15 (see FIG. 1), and the input port 27 is connected to the magnetic compass 14. be done.

The CPU 21 is an arithmetic device that executes various calculations for controlling the operation of the plotter 12 according to program data 22 a stored in the flash memory 22 .

The flash memory 22 is a rewritable non-volatile memory for storing fixed value data, etc., in addition to storing program data 22a. A non-rewritable non-volatile memory (for example, mask ROM) may be used instead of the flash memory 22 . The flash memory 22 stores at least image data 22b as fixed value data.

The image data 22b is data necessary for drawing an image to be displayed on the display device 16. FIG. For example, the flash memory 22 stores data necessary for drawing a ship mark 16a and a sea map 16b to be displayed on the display device 16 as image data 22b.

The RAM 23 is a rewritable volatile memory, and temporarily stores various data when the CPU 21 executes the program. The RAM 23 stores at least velocity data 23a, movement azimuth data 23b, compass azimuth angle data 23c, error data 23d, and correction value data 23e.

The speed data 23a is data indicating information on the moving speed of the vessel 11 obtained by the GPS antenna 15 receiving radio waves from the GPS satellites S. FIG. The speed data 23a is transmitted from the GPS antenna 15 to the main body 13 using the NMEA format RMC sentence, VTG sentence, etc., which is a protocol used for communication of marine electronic equipment standardized by the National Marine Electronics Association (NMEA). . The speed data 23a is obtained once per second.

The movement azimuth angle data 23 b is data indicating the movement azimuth angle M of the ship 11 . The moving azimuth angle M is an azimuth angle indicating the moving direction of the vessel 11 obtained from the difference in temporal changes in position information (latitude and longitude) when the vessel 11 sails. The moving azimuth angle M is obtained as the true azimuth angle T because it is obtained without being affected by magnetism. Therefore, the difference between the compass azimuth angle C and the moving azimuth angle M is the error E of the magnetic compass 14 .

The moving azimuth angle M is acquired once per second by a moving azimuth angle acquisition process described later using an NMEA format RMC sentence, a VTG sentence, or the like transmitted from the GPS antenna 15 to the main body 13 .

The compass azimuth angle data 23 c is data indicating the compass azimuth angle C measured by the magnetic compass 14 . The compass azimuth angle C is acquired once per second by a compass azimuth angle acquisition process described later using an NMEA format HDG sentence, HDM sentence, or the like transmitted from the magnetic compass 14 to the main body 13 .

The error data 23d is data indicating the error E included in the compass azimuth angle C at a certain time. The error E is obtained from the compass azimuth angle C and the moving azimuth angle M by the following equation (3) in the correction value calculation process described later. The error data 23d is used when calculating the correction value data 23e in the correction value calculation process described later.

E=CM (3)

The correction value data 23e is a coefficient used when correcting the compass azimuth angle C. FIG. The correction value data 23e is an arithmetic average value of five (5 seconds) error data 23d when the compass azimuth C and the movement azimuth M are acquired every second, and is calculated as a correction value to be described later. Required by processing.

The display controller 24 controls display of the display device 16 based on control from the CPU 21 . The VRAM 25 is a memory provided with a frame buffer for storing one frame of image to be displayed on the display device 16 .

When receiving an image drawing instruction from the CPU 21, the display controller 24 reads the necessary image data 22b from the flash memory 22, and draws the instructed image at the position instructed by the CPU 21 in the frame buffer of the VRAM 25. . The display controller 24 then reads out the image drawn in the frame buffer and causes the display device 16 to display it.

The GPS I/F 26 inputs the signal from the GPS satellite S received by the GPS antenna 15 to the CPU 21 . The input port 27 inputs a signal from the magnetic compass 14 to the CPU 21 .

Next, the timing at which the plotter 12 acquires the correction value data 23e will be described with reference to FIG. FIG. 4 is a schematic diagram showing the timing of acquiring the correction value data 23e. As shown in FIG. 4, the vertical axis represents the speed of the ship 11 and the horizontal axis represents time. Moving azimuth angle data 23b obtained during the first 5 seconds when the ship 11 sailed straight ahead at a speed of 10 knots (18.52 km/h) or more continuously for 5 seconds. , the correction value data 23e is obtained based on the compass azimuth angle data 23c.

The reason why the correction value data 23e is acquired when the moving speed of the ship 11 continues for 5 seconds at 10 knots or more is that the hull is sailing in a stable attitude without being affected by tidal currents.

Even if the ship 11 continues to sail at a speed of 10 knots or more for more than 5 seconds, once the correction value data 23e is acquired, even if the speed is maintained at 10 knots or more, the correction value data 23e will not be acquired after the first 5 seconds. don't get This is because the correction value data 23e are unlikely to change during navigation at a speed of 10 knots or more.

Further, even if the speed of the ship 11 changes from 10 knots or more to 10 knots or less and then sails again at a speed of 10 knots or more for 5 seconds or more, no new correction value data 23e is acquired. Since the magnetic environment around the magnetic compass 14 is less likely to change while the plotter 12 is powered on, the error E is less likely to change. Therefore, in order to avoid acquiring the correction value data 23e multiple times, new correction value data 23e is not acquired.

Next, the movement azimuth acquisition process will be described with reference to FIG. The moving azimuth angle acquisition process is a process for acquiring the moving azimuth angle M. FIG. FIG. 5 is a flow chart showing the moving azimuth acquisition process.

This moving azimuth acquisition process is executed when the CPU 21 receives an NMEA format sentence (for example, an RMC sentence or a VTG sentence) transmitted from the GPS antenna 15 . A program for executing the moving azimuth acquisition process is included in the program data 22a (see FIG. 3) of the flash memory 22. FIG.

First, when the moving azimuth angle acquisition process is started by the CPU 21, information on the moving azimuth (moving azimuth) of the ship 11 included in the NMEA format sentence is acquired (S101). Next, the movement direction acquired in the process of S101 is smoothed (S102). In this smoothing, filtering is performed using a plurality of previously obtained moving directions to remove noise.

Next, phase adjustment is performed (S103). Phase adjustment is a process for eliminating the difference between the reception timing of the NMEA format sentence transmitted from the GPS antenna 15 and the NMEA format sentence transmitted from the magnetic compass 14 acquired at the same time. be. In this embodiment, since the NMEA format sentence transmitted from the magnetic compass 14 is received two seconds earlier, the compass azimuth angle C is acquired in the process of S123 of the compass azimuth acquisition process described later. Delay the timing by 2 seconds. Therefore, no substantial processing is executed in the processing of S103.

Next, the movement azimuth smoothed in the process of S102 and phase-adjusted in the process of S103 is stored as the movement azimuth M in the movement azimuth angle data 23b of the RAM 23 (S104), and the movement azimuth acquisition process ends.

Next, the compass azimuth acquisition process will be described with reference to FIG. The compass azimuth angle acquisition process is a process for acquiring the compass azimuth angle C. FIG. FIG. 6 is a flow chart showing compass azimuth angle acquisition processing.

This compass azimuth acquisition process is executed when the CPU 21 receives an NMEA format sentence (for example, HDG sentence, HDM sentence, etc.) transmitted from the magnetic compass 14 . The program for executing the compass azimuth acquisition process is included in the program data 22a (see FIG. 3) of the flash memory 22. FIG.

First, when the compass azimuth angle acquisition process is started by the CPU 21, the magnetic azimuth information included in the NMEA format sentence is acquired (S121). The magnetic orientation obtained in the process of S121 is smoothed (S122), and the phase is adjusted (S123). In the NMEA format sentence transmitted from the GPS antenna 15 and the NMEA format sentence transmitted from the magnetic compass 14 acquired at the same time, the CPU 21 receives the NMEA format sentence transmitted from the magnetic compass 14 at the same time. is two seconds earlier, the timing of acquiring the magnetic orientation is delayed by two seconds in the process of S123. The reason why the phase is adjusted here is to obtain the error E using the compass azimuth angle C and the moving azimuth angle M at the same time. Then, since correction value data e obtained based on this error E is used to correct the compass azimuth angle C thereafter, there is no need to adjust the phase during correction.

Next, the magnetic direction smoothed in the process of S122 and phase-adjusted in the process of S123 is stored as the compass direction C in the compass direction data 23c of the RAM 23 (S124), and the compass direction angle acquisition process ends.

Next, the correction value calculation process will be described with reference to FIG. The correction value calculation process is a process for acquiring the correction value data 23e. FIG. 7 is a flow chart showing correction value calculation processing.

This correction value calculation process is a process executed by the CPU 21 from when the power of the plotter 12 is turned on until the first correction value data 23e is obtained. A program for executing the correction value calculation process is included in the program data 22a (see FIG. 3) of the flash memory 22. FIG.

First, when the correction value calculation process is started by the CPU 21, it is determined whether the speed of the ship 11 is 10 knots or more and 5 seconds have passed (S1). The speed of the ship 11 is determined based on the speed information contained in the speed data 23a. If it is determined that the speed is 10 knots or more and five seconds have not elapsed (S1: No), the ship 11 is not sailing in a stable attitude and the variation in the moving azimuth angle M increases. The processing of S1 is repeated without acquiring. If it is determined that the speed is 10 knots or more and 5 seconds have passed (S1: Yes), the ship 11 is sailing in a stable attitude, so the process proceeds to S2.

Next, the moving azimuth angles M (five) for the first 5 seconds when the speed became 10 knots or more are read from the moving azimuth angle data 23b (S2), and the compass headings for the first 5 seconds when the speed became 10 knots or more are read. The angles C (five) are read from the compass azimuth angle data 23c (S3).

Next, it is determined whether or not the difference between the maximum value and the minimum value of the compass azimuth angle C acquired after the speed reaches 10 knots or more is within a predetermined range (for example, 3°) (S4). If it is not within the predetermined range (S4: No), it is determined that the ship 11 is not proceeding straight, and the process returns to S1. On the other hand, if it is within the predetermined range (S4: Yes), it is determined that the ship 11 is traveling straight ahead, and the process proceeds to S5.

Next, the moving azimuth M read in the process of S2 at the same time as the compass azimuth C read in the process of S3 is subtracted from the compass azimuth C read in the process of S3, and the error E contained in each of the five compass azimuths C is calculated. , is calculated using the above equation (3) (S5). The result is stored in RAM 23 as error data 23d (S6).

Next, the five error data 23d stored in the process of S6 are read (S7), and the arithmetic mean of these error data 23d is obtained (S8). Then, the calculation result of the process of S10 is stored in the RAM 23 as the correction value data 23e (S9), and the correction value calculation process ends.

Next, correction processing will be described with reference to FIG. The correction processing is processing for correcting the error E included in the compass azimuth angle C. FIG. FIG. 8 is a flowchart showing correction processing.

This correction process is a process executed by the CPU 21 each time the compass azimuth angle C is acquired. The program for executing the correction process is included in the program data 22a (see FIG. 3) of the flash memory 22. FIG.

First, when the correction process is started by the CPU 21, the CPU 21 determines whether or not the correction value data 23e is stored in the RAM 23 (S30). If it is determined that there is no correction value data 23e (S30: No), the latest compass azimuth angle C is read from the compass azimuth angle data 23c stored in the RAM 23 (S35), This is output to the display controller 24 as the azimuth direction (S34). If it is determined that there is the correction value data 23e (S30: Yes), since there is a coefficient for correcting the compass azimuth angle C, the process proceeds to S31.

In the processing of S31, the latest compass azimuth angle C is read from the compass azimuth angle data 23c stored in the RAM 23 (S31), and the correction value data 23e stored in the RAM 23 is read (S32). Thereafter, the correction value data 23e read in the process of S32 is subtracted from the compass azimuth angle C read in the process of S31 (S33). As a result, the error E included in the compass azimuth angle C is removed, and the true azimuth angle T can be obtained. Then, this true azimuth angle T is output to the display controller 24 as the azimuth to which the ship 11 is heading (S34), and the correction process is terminated.

As described above, according to the plotter 12 according to the first embodiment, when the period in which the speed of the ship 11 is 10 knots or more continues for 5 seconds, the difference between the compass azimuth C and the moving azimuth M Then, correction value data 23e is obtained. If the period in which the speed of the ship 11 is 10 knots or more continues for 5 seconds, the hull is sailing in a stable attitude during that period without being affected by the tidal current. At this time, the moving azimuth angle M of the ship 11 is the azimuth angle to which the ship 11 is facing. The user can acquire the correction value data 23e only by sailing the ship at a speed of 10 knots or more for 5 seconds, so that the error E between the compass azimuth C and the moving azimuth M can be corrected. Therefore, there is an effect that the user can save the trouble of correcting the compass azimuth angle C error.

Further, five error data 23d, which are differences obtained by subtracting the moving azimuth angle M from the compass azimuth angle C at the same time during the five seconds in which the ship 11 moves at 10 knots or more, are obtained, and these are averaged to obtain correction value data 23e. is obtained. As a result, the correction value data 23e can be obtained based on the five moving azimuth angles M and the compass azimuth angles C during five seconds of movement at 10 knots or more. Therefore, it is possible to reduce correction errors caused by variations in the movement azimuth M and the compass azimuth C at each time. Therefore, there is an effect that the accuracy of correction can be improved.

Further, the correction value calculation process is executed by the CPU 21 from when the power of the plotter 12 is turned on until the correction value data 23e is acquired for the first time. That is, if the ship 11 continues to sail at 10 knots or more even after acquiring the correction value data 23e, acquisition of new correction value data 23e is not executed. While the hull is sailing in a stable attitude at a speed of 10 knots or more, the difference between the moving azimuth M and the compass azimuth C does not change significantly. Therefore, it is unlikely that the error E will change while the hull is sailing in a stable attitude at 10 knots or more. As a result, it is possible to prevent the correction value data 23e from being repeatedly acquired even though the error E has not changed.

Further, the correction value data 23e is acquired when the difference between the maximum value and the minimum value of the compass azimuth angle C is within a predetermined range (for example, 3°) during 5 seconds during which the ship 11 moves at 10 knots or more. . When the speed of the ship is 10 knots or more and the difference between the maximum value and the minimum value of the compass azimuth angle C is within a predetermined range, the hull proceeds straight in a stable attitude. By acquiring the correction value data 23e in this state where the bow is stable, it is possible to reduce correction errors due to the compass azimuth angle C being unstable. As a result, there is an effect that the accuracy of correction can be improved.

The correction value calculation process is executed by the CPU 21 from when the power of the plotter 12 is turned on until the first correction value data 23e is obtained. That is, when the speed of the ship 11 continues at 10 knots or more for five seconds after the power is turned on, the correction value data 23e is obtained. As a result, new correction value data 23e can be obtained each time the power is turned on. When the power is turned on, it is possible that the plotter 12 has not been used for some time. During such periods of non-use, the user is likely to place magnetic objects (e.g., spanners, fishing tackle, etc.) that affect the magnetic compass 14 in the vicinity of the magnetic compass 14, causing the error to change. sell. Since the plotter 12 according to the first embodiment can obtain new correction value data 23e after the power is turned on, it has the effect of being able to cope with such a change in error before the power is turned on.

Next, a plotter 12 according to a second embodiment will be described with reference to FIGS. 9 to 14. FIG. The plotter 12 in the first embodiment acquires the correction value data 23e based on the error data 23d, which is the difference between the compass azimuth C and the movement azimuth M. On the other hand, the plotter 12 in the second embodiment obtains the moving azimuth angle M corresponding to each compass azimuth angle C when the compass azimuth angle C changes. Then, the plotter 12 in the second embodiment performs correction by converting the compass azimuth angle C into the movement azimuth angle M corresponding to the compass azimuth angle. Since other configurations of the plotter 12 are the same as those of the first embodiment, description thereof will be omitted. Hereinafter, the same reference numerals as those in the first embodiment are given to the same configurations, and the description thereof will be omitted.

First, an outline of the plotter 12 according to the second embodiment will be described with reference to FIG. FIG. 9 is a schematic diagram showing an outline of correction. As shown in FIG. 9, the plotter 12 divides all directions (0° to 360°) around the ship 11 into eight regions (regions 1 to 8) in 45° increments. Then, the plotter 12 stores a representative value of the compass azimuth angle C and the movement azimuth angle M corresponding to the compass azimuth angle C for each area. The compass azimuth angle C and the moving azimuth angle M corresponding to the compass azimuth angle C are actually measured values when the ship 11 continues to go straight in that area at 10 knots or more for 5 seconds.

For example, if the compass azimuth C and the movement azimuth M corresponding to the compass azimuth C are not acquired in the area 6, the user steers the ship 11 toward the azimuth of the area 6 at 10 knots or more for 5 seconds or more. By traveling straight, a new compass azimuth C and a movement azimuth M corresponding to the new compass azimuth C are obtained.

Next, the electrical configuration of plotter 12 will be described with reference to FIG. FIG. 10 is a block diagram showing the electrical configuration of the plotter 12. As shown in FIG. The flash memory 22 stores area data 22c and an area correction table 22d in addition to the program data 22a and image data 22b stored in the flash memory 22 in the first embodiment. The region data 22c is data for determining which compass azimuth angle C is included in which region. The area correction table 22d is a table that stores the compass azimuth angle C and the movement azimuth angle M corresponding to the compass azimuth angle C for each area. The area correction table 22d is generated by area correction table generation processing, which will be described later, and is used when generating an omnidirectional correction table 23f, which will be described later.

The RAM 23 stores an omnidirectional correction table 23f instead of the error data 23d and correction value data 23e stored in the first embodiment. The omnidirectional correction table 23f is a table that stores compass azimuth angles C in all azimuths and movement azimuth angles M corresponding to the compass azimuth angles C in increments of 1°. The omnidirectional correction table 23f converts the compass azimuth angle C for each area stored in the area correction table 22d and the movement azimuth angle M corresponding to the compass azimuth angle C between areas in an omnidirectional correction table generation process described later. Obtained by interpolation. Further, the omnidirectional correction table 23f is used when compass azimuth angle C is corrected.

Since the omnidirectional correction table 23f has a large capacity, it is stored in the RAM 23, which is a large-capacity, inexpensive memory. Therefore, the area correction table 22d is erased when the power is turned off, but since the area correction table 22d is stored in the nonvolatile flash memory 22, the area correction table 22d can be used when the power is turned on again after the power is turned off. Then, the omnidirectional correction table 23f is obtained.

Next, the area correction table 22d and the omnidirectional correction table 23f will be described with reference to FIG. FIG. 11A is a schematic diagram of the area correction table 22d, and FIG. 11B is a schematic diagram of the omnidirectional correction table 23f. As shown in FIG. 11A, the area correction table 22d stores one compass azimuth angle C and one movement azimuth angle M for each of the areas 1 to 8. FIG. For example, in area 1, it is stored that the moving azimuth angle M is 22 degrees when the compass azimuth angle C is measured as 18 degrees. Note that the compass azimuth angle C and the moving azimuth angle M are -1 in the area 6, which means that the compass azimuth angle C and the moving azimuth angle M are not measured in the area 6. FIG.

As shown in FIG. 11(b), the omnidirectional correction table 23f stores compass azimuth angles C from 0° to 359° in increments of 1°. Then, the moving azimuth M corresponding to each compass azimuth C is stored. For example, the movement azimuth M is 2 degrees when the compass azimuth C is 3 degrees. That is, the orientation (true azimuth angle T) of the ship 11 is 2 degrees when the compass azimuth angle C is measured to be 3 degrees. Therefore, when the ship 11 is sailing and the compass azimuth angle C is corrected when the compass azimuth angle C is 3°, the corrected compass azimuth angle C (true azimuth angle T) becomes 2°.

Next, referring to FIG. 12, the region correction table generation processing will be described. The area correction table generation process is a process for generating the area correction table 22d. FIG. 12 is a flowchart showing area correction table generation processing.

This area correction table generation process is executed while the power of the plotter 12 is on or after the user operates the operation button 17 to instruct the start of execution of the plotter function, and the end of the execution is instructed. This process is repeatedly executed by the CPU 21 until the time. A program for executing the area correction table generation process is included in the program data 22a (see FIG. 10) of the flash memory 22. FIG.

First, when the area correction table generation process is started by the CPU 21, it is determined whether or not five seconds have elapsed while the speed of the ship 11 is 10 knots or more (S51). If it is determined that the speed is 10 knots or more and five seconds have not elapsed (S51: No), the process of S51 is repeated because the ship 11 is not sailing in a stable attitude. If it is determined that the speed is 10 knots or more and five seconds have passed (S51: Yes), the ship 11 is sailing in a stable attitude, so the process proceeds to S52.

Next, the compass bearing angles C (five) for the first five seconds when the speed became 10 knots or more are read from the compass bearing angle data 23c of the RAM 23 (S52), and the first five seconds when the speed of the ship 11 became 10 knots or more It is determined whether or not the difference between the maximum value and the minimum value of the compass azimuth angle C for 5 seconds is within a predetermined range (eg, 3°) (S53). If it is determined that it is not within the predetermined range (S53: No), the ship 11 is not proceeding straight, so the process returns to S51. If it is determined that it is within the predetermined range (S53: Yes), the ship 11 is proceeding straight ahead, so the process proceeds to S54.

Next, the arithmetic mean value of the compass azimuth angles C (five) read in the process of S53 is obtained (S54). Then, an area including the average value of the compass azimuth angle C obtained in the process of S54 is selected from the area data 22c (S55).

Next, the moving azimuth angles M (five) obtained at the same time as the compass azimuth angles C read in the processing of S52 are read from the moving azimuth angle data 23b of the RAM 23 (S56), and their arithmetic mean values are obtained ( S57). Then, in the area correction table 22d of the flash memory 22, the arithmetic mean value of the compass azimuth angle C obtained in the process of S54 and the moving azimuth angle obtained in the process of S57 are entered in the column of the area selected in the process of S55. The arithmetic mean value of M is written (S58).

Next, the difference between the compass azimuth C written in the process of S58 and the movement azimuth M is compared with the difference between the compass azimuth C and the movement azimuth M before the process of S58 is performed, It is determined whether the result of subtracting the difference after writing from the difference before writing is within a predetermined range (eg -90° to +90°) (S59). If it is determined that it is within the predetermined range (S59: Yes), it is assumed that the error E has not changed significantly, and the process returns to S51. On the other hand, if it is determined that it is not within the predetermined range (S59: No), the error E between the previous time and this time has changed greatly, so it is highly likely that an error has occurred in all areas. The movement azimuth M and the compass azimuth C of all areas except the area written in the process are deleted from the area correction table 22d (S60), and the process returns to S51.

Next, omnidirectional correction table generation processing will be described with reference to FIG. The omnidirectional correction table generation process is a process for generating the omnidirectional correction table 23f. FIG. 13 is a flowchart showing omnidirectional correction table generation processing.

This omnidirectional correction table generation process is a process executed by the CPU 21 when the power of the plotter 12 is turned on or when the area correction table 22d is rewritten. A program for executing the omnidirectional correction table generation process is included in the program data 22a (see FIG. 10) of the flash memory 22. FIG.

First, when the omnidirectional correction table generation process is started by the CPU 21, a predetermined area is set as area a (S80), and a is set to 1 (S81). a is a variable for specifying the area.

Next, referring to the area correction table 22d, it is determined whether or not the compass azimuth angle C and the moving azimuth angle M are stored in the area a in the area correction table 22d (S82). If it is determined that the compass azimuth C and the movement azimuth M of the area a are stored (S82: Yes), the compass azimuth C and the movement azimuth M of the area a in the area correction table 22d are read. (S83), the process proceeds to S84. On the other hand, if it is determined that the compass azimuth C and movement azimuth M of the area a are not stored in the area correction table 22d (S82: No), the process proceeds to S84.

Next, 1 is added to a (S84), and it is determined whether or not a is 8 or less (S85). If it is determined that a is 8 or less (S85: Yes), it is determined whether or not the compass azimuth C and movement azimuth M are stored in the area correction table 22d for all areas (8). Since it is not finished, the process returns to S82. If it is determined that a is not 8 or less (S85: No), it is determined whether or not the compass azimuth C and movement azimuth M are stored in the area correction table 22d for all the areas (8). Since it is finished, the process proceeds to S86.

In the process of S86, the area correction table 22d is referenced to determine the number of areas in which the compass azimuth C and the movement azimuth M corresponding to the compass azimuth C are stored in the area correction table 22d. If the number of areas in which the compass azimuth C and the moving azimuth M corresponding to the compass azimuth C are stored is "0" (S86: "0"), interpolation cannot be performed, so the omni-azimuth correction table End the generation process.

When the number of areas storing the compass azimuth C and the movement azimuth M corresponding to the compass azimuth C is "1" (S86: "1"), the process proceeds to S87. Then, by subtracting the error E between the compass azimuth angle C and the moving azimuth angle M corresponding to the compass azimuth angle C from the compass azimuth angle C when the compass azimuth angle C changes in increments of 1°, the compass A moving azimuth angle M corresponding to a change in the azimuth angle C in increments of 1° is obtained (S87).

If the number of areas in which the compass azimuth C and the movement azimuth M corresponding to the compass azimuth C are stored is "2" to "8" (S86: "2" to "8"), Go to processing. Then, the compass azimuth angle C read in the process of S83 and the moving azimuth angle M are linearly interpolated between the regions, and the corresponding moving azimuth angle M is obtained when the compass azimuth angle C changes in increments of 1° (S88). . Then, the result of the process of S87 or the result of the process of S88 is stored in the omnidirectional correction table 23f of the RAM 23 (S89), and the omnidirectional correction table generation process ends.

Next, omnidirectional correction processing will be described with reference to FIG. The omnidirectional correction process is a process for correcting the compass azimuth angle C. FIG. FIG. 14 is a flowchart showing omnidirectional correction processing.

This omnidirectional correction process is a process executed by the CPU 21 each time the compass azimuth angle C is acquired. The program for executing the omnidirectional correction process is included in the program data 22a (see FIG. 10) of the flash memory 22. FIG.

First, when the omnidirectional correction process is started by the CPU 21, the latest compass azimuth angle C is read from the compass azimuth angle data 23c stored in the RAM 23 (S90), and the omnidirectional correction table 23f stored in the RAM 23 is read (S90). S91).

Next, it is determined whether or not the moving azimuth angle M corresponding to the compass azimuth angle C read in the process of S90 is stored in the omnidirectional correction table 23f (S92). If it is determined that the movement azimuth angle M corresponding to the compass azimuth angle C is not stored (S92: No), the compass azimuth angle C cannot be corrected, so the display controller sets the compass azimuth angle C as the azimuth to which the ship 11 is facing. 24 (S94), and the omnidirectional correction process ends. On the other hand, if it is determined that the moving azimuth angle M corresponding to the compass azimuth angle C is stored (S92: Yes), the moving azimuth angle M corresponding to the compass azimuth angle C read in the process of S90 is corrected in all directions. Search from the table 23f and convert the value of the compass azimuth angle C into the corresponding movement azimuth angle M (S93).

Then, the converted compass azimuth angle C is output to the display controller 24 as the azimuth to which the ship 11 is facing (S94), and the omnidirectional correction process is terminated.

As described above, according to the plotter 12 according to the second embodiment, the entire azimuth around the hull of the ship 11 is divided into eight regions, and the azimuth angle toward which the ship is facing is included based on the compass azimuth angle C. A compass bearing angle C in that area and a moving bearing angle M corresponding to the compass bearing angle C are obtained. A compass azimuth angle C and a movement azimuth angle M corresponding to the compass azimuth angle C are stored in the area correction table 22d for each area. Thereby, correction can be performed using a different coefficient for each region. Therefore, even if the geomagnetism is different due to the difference in the orientation and the error is different, there is an effect that the optimum coefficient can be set for each area.

Also, when the compass azimuth C and the movement azimuth M corresponding to the compass azimuth C are newly acquired in the area 1, the compass azimuth C already stored in that area and the compass azimuth C The difference between the newly acquired compass azimuth angle C and the moving azimuth angle M is subtracted from the difference from the moving azimuth angle M corresponding to . If the result of the subtraction is within the predetermined range, the already stored compass azimuth C and the movement azimuth M corresponding to the compass azimuth C are deleted from the area correction table 22d and newly calculated. The compass azimuth angle C and the movement azimuth angle M corresponding to the compass azimuth angle C are stored in the area correction table 22d. If the result of the subtraction is not within the predetermined range, the compass azimuth C of all areas excluding the newly stored area that has already been stored and the movement azimuth M corresponding to the compass azimuth C are stored in the storage means. removed from

As a result, an error in the compass azimuth angle C becomes large due to reasons such as a large change in the installation situation of the magnetic compass 14. is newly obtained compass azimuth angle C and moving azimuth angle M corresponding to the compass azimuth angle C, which is greatly different from the compass azimuth angle C and the moving azimuth angle corresponding to the compass azimuth angle C M can be deleted. Therefore, it is possible to prevent the compass azimuth angle C with a large error and the moving azimuth angle M corresponding to the compass azimuth angle C from being used. Therefore, there is an effect that it is possible to prevent erroneous information from being displayed to the user.

The compass azimuth angle C for each area stored in the area correction table 22d and the movement azimuth angle M corresponding to the compass azimuth angle C are the azimuth angles obtained in one azimuth included in the area. A compass bearing angle C and a moving bearing angle M corresponding to the compass bearing angle C are interpolated between the stored first and second areas. Then, the compass azimuth angle C of the first area and the moving azimuth angle M corresponding to the compass azimuth angle C are acquired, and the compass azimuth angle C of the second area and the moving azimuth angle corresponding to the compass azimuth angle C A compass azimuth angle C in the azimuth sandwiched between the acquired azimuth angle M and the moving azimuth angle M corresponding to the compass azimuth angle C are acquired and stored in the omnidirectional correction table 23f. As a result, even if the ship 11 does not navigate in all directions, the compass direction C of the first region and the movement direction M corresponding to the compass direction C can be obtained and the compass direction of the second region can be obtained. Using the compass azimuth C suitable for the azimuth between the angle C and the azimuth from which the moving azimuth M corresponding to the compass azimuth C was acquired and the moving azimuth M corresponding to the compass azimuth C There is an effect that it can be corrected by

In addition, the plotter 12 according to the second embodiment has the same effects as the first embodiment due to the same configuration.

The present invention has been described above based on the embodiments, but the present invention is not limited to the above-described embodiments, and it is easily understood that various modifications and improvements are possible without departing from the scope of the present invention. It can be inferred. For example, each embodiment can be implemented by adding a part or a plurality of parts of the configuration of each other embodiment to the embodiment or replacing it with a part or a plurality of parts of the configuration of the embodiment. You may make it comprise by changing a form. Further, the numerical values given in the above embodiment are only examples, and it is naturally possible to employ other numerical values.

In each of the above embodiments, when the ship 11 continues at a speed of 10 knots or more for 5 seconds, the correction value data 23e is generated in the correction value calculation process, or the area correction table 22d is generated in the area correction table generation process. , but not limited to. For example, when the speed of the ship 11 changes from less than 10 knots to 10 knots or more and the speed of 10 knots or more is continued for 5 seconds, the correction value data 23e is generated in the correction value calculation process, or the area correction table The area correction table 22d may be generated in the generation process. Since the speed of the ship 11 changes from below 10 knots to above 10 knots during acceleration, the hull is stabilized. Therefore, it is possible to avoid generating the correction value data 23e in the correction value calculation process or generating the area correction table 22d in the area correction table generation process during deceleration when the hull attitude is unstable.

In the second embodiment, the moving azimuth angle M corresponding to the compass azimuth angle C when the compass azimuth angle C changes in increments of 1° is obtained, and the compass azimuth angle C is converted into the corresponding moving azimuth angle M. Although the compass azimuth angle C is corrected, it is not limited to this. For example, an error E between the compass azimuth angle C and the moving azimuth angle M when the compass azimuth angle C changes in increments of 1° may be obtained and used for correction. At this time, an arithmetic mean of the errors E may be obtained from the errors E between a plurality of compass azimuth angles C and the movement azimuth angles M at the same time, and the arithmetic average error E may be used for correction.

In the second embodiment, the region correction table generation process updates the region correction table 22d every time the speed of 10 knots or more continues for 5 seconds, but it is not limited to this. For example, after acquiring the compass azimuth C and the movement azimuth M corresponding to the compass azimuth C in a certain area, while the power is ON, the compass azimuth C and the movement azimuth M are newly acquired in that area. and may be non-executed.

In each region, the compass azimuth C when the speed of the ship 11 continues for 5 seconds at 10 knots or more for the first time after the power is supplied and the movement azimuth M corresponding to the compass azimuth C are stored in the region correction table 22d. , the compass azimuth C and the moving azimuth M may be used until the power of the plotter 12 is turned off.

In each of the above embodiments, when the speed of the ship 11 is 10 knots or more, the correction value data 23e is generated in the correction value calculation process, or the area correction table 22d is generated in the area correction table generation process. It is not limited to this. The speed of the ship 11 may be any speed as long as the speed allows the hull to move in a stable attitude. Also, the speed may be changeable by the user, or may be changeable according to some conditions. For example, the ship 11 is provided with a tidal current meter for measuring the tidal current and a judgment means for judging the speed of the tidal current measured by the tidal current meter. 23e, or the area correction table 22d may be generated in the area correction table generation process. On the other hand, in a sea area where the tidal current is fast, the correction value data 23e may be generated in the correction value calculation process or the area correction table 22d may be generated in the area correction table generation process when the current is 12 knots or more.

In each of the above embodiments, when the speed of the ship 11 continues at 10 knots or more for 5 seconds, the correction value data 23e is generated in the correction value calculation process, or the area correction table 22d is generated in the area correction table generation process. , the time is not limited to this, and any time may be set. Also, the time may be changeable by the user, or may be changeable according to some conditions. For example, the ship 11 is provided with a tidal current meter for measuring the tidal current and a judgment means for judging the speed of the tidal current measured by the tidal current meter. If it continues, the correction value data 23e may be generated in the correction value calculation process, or the area correction table 22d may be generated in the area correction table generation process. On the other hand, if the hull attitude becomes unstable in a sea area with a fast tidal current, if the speed of 10 knots or more continues for 10 seconds, the correction value data 23e is generated in the correction value calculation process, or the area correction is performed in the area correction table generation process. A table 22d may be generated.

Also, the speed of the ship 11 may be used instead of the tidal current as the condition for setting the time. For example, when the speed of 10 knots or more and less than 15 knots continues for 5 seconds, the correction value data 23e may be generated in the correction value calculation process, or the area correction table 22d may be generated in the area correction table generation process. On the other hand, when the speed of the ship 11 is 15 knots or more, the hull attitude becomes more stable. The area correction table 22d may be generated in the table generation process.

In the second embodiment, the area correction table 22d is stored in the flash memory 22 and the omnidirectional correction table 23f is stored in the RAM 23, but the present invention is not limited to this. For example, both the area correction table 22d and the omnidirectional correction table 23f may be stored in the flash memory 22. FIG. Alternatively, both the area correction table 22d and the omnidirectional correction table 23f may be stored in the RAM 23. FIG. When the area correction table 22d is stored in the RAM 23 and the power is turned off and then turned on, the area correction table 22d contains no data and cannot be corrected. Therefore, if correction is not possible, the color of the ship mark 16a displayed on the display device 16 may be changed to inform the user that the direction of the ship mark 16a is not corrected. good.

In each of the above-described embodiments, the GPS antenna 15 is used to acquire the sea position information of the ship 11, but the present invention is not limited to this. Any satellite positioning system that can acquire position information based on radio waves from satellites may be used. For example, a satellite positioning system such as Galileo may be used.

In each of the embodiments described above, the moving azimuth angle M is obtained from the GPS antenna 15, but the present invention is not limited to this. For example, latitude and longitude information may be acquired from the GPS antenna 15, and the moving direction may be obtained from the temporal change of the latitude and longitude information by the CPU 21. FIG.

A plotter according to the present invention includes a fish finder and a searchlight sonar (PPI sonar) device having a plotter function.

11 Vessel (Ship)
12 plotter 13 main body (position information acquisition means)
16 display device (display means)
22 Flash memory (part of storage means)
23 RAM (part of storage means, interpolation storage means)
S1 to S9, S51 to S58 (coefficient acquisition means)
S33, S34, S93, S94 (correction means)
S55 (area determination means)
S59 (comparison means)
S58, S60 (update means)
S88 (interpolating means)
S101 to S104 (moving azimuth acquisition means)
S121 to S124 (compass azimuth acquisition means)

Claims (7)

position information acquisition means for acquiring position information based on radio waves from satellites;
Compass azimuth acquisition means for acquiring the compass azimuth angle transmitted by a magnetic compass mounted on a ship and outputting a compass azimuth angle determined based on geomagnetism;
display means for displaying the position of the ship based on the position information obtained by the position information obtaining means, and displaying the direction of the ship based on the compass bearing angle obtained by the compass bearing angle obtaining means; A plotter comprising
A moving azimuth angle obtaining means for obtaining a moving azimuth angle obtained from the temporal change of the position information;
When a period in which the moving speed of the ship is equal to or higher than a predetermined speed continues for a predetermined period, the moving azimuth obtained by the moving azimuth obtaining means and the compass azimuth obtained by the compass azimuth obtaining means during the predetermined period. a coefficient acquiring means for acquiring a correction coefficient used for correcting the compass azimuth angle based on the compass azimuth angle;
storage means for storing the coefficients obtained by the coefficient obtaining means;
correction means for correcting the compass azimuth based on the coefficients stored by the storage means ;
The plotter according to claim 1 , wherein said coefficient acquiring means does not acquire new coefficients if the moving speed of said ship is equal to or higher than said predetermined speed even after acquiring said coefficients . position information acquisition means for acquiring position information based on radio waves from satellites;
Compass azimuth acquisition means for acquiring the compass azimuth angle transmitted by a magnetic compass mounted on a ship and outputting a compass azimuth angle determined based on geomagnetism;
display means for displaying the position of the ship based on the position information obtained by the position information obtaining means, and displaying the direction of the ship based on the compass bearing angle obtained by the compass bearing angle obtaining means; A plotter comprising
A moving azimuth angle obtaining means for obtaining a moving azimuth angle obtained from the temporal change of the position information;
When a period in which the moving speed of the ship is equal to or higher than a predetermined speed continues for a predetermined period, the moving azimuth obtained by the moving azimuth obtaining means and the compass azimuth obtained by the compass azimuth obtaining means during the predetermined period. a coefficient acquiring means for acquiring a correction coefficient used for correcting the compass azimuth angle based on the compass azimuth angle;
storage means for storing the coefficients obtained by the coefficient obtaining means;
correction means for correcting the compass azimuth based on the coefficients stored by the storage means;
The plotter, wherein the coefficient obtaining means obtains the coefficient when the difference between the maximum value and the minimum value of the compass azimuth angle is within a predetermined range for a specific period or longer. position information acquisition means for acquiring position information based on radio waves from satellites;
Compass azimuth acquisition means for acquiring the compass azimuth angle transmitted by a magnetic compass mounted on a ship and outputting a compass azimuth angle determined based on geomagnetism;
display means for displaying the position of the ship based on the position information obtained by the position information obtaining means, and displaying the orientation of the ship based on the compass bearing angle obtained by the compass bearing angle obtaining means; A plotter comprising
An area for determining the area including the azimuth of the direction of the ship based on the compass azimuth angle obtained by the compass azimuth acquisition means by dividing the entire azimuth around the hull of the ship into a plurality of areas. means of judgment;
A moving azimuth angle obtaining means for obtaining a moving azimuth angle obtained from the temporal change of the position information;
When a period in which the moving speed of the ship is equal to or higher than a predetermined speed continues for a predetermined period, the moving azimuth obtained by the moving azimuth obtaining means and the compass azimuth obtained by the compass azimuth obtaining means during the predetermined period of time. a coefficient acquiring means for acquiring a correction coefficient used for correcting the compass azimuth angle in the area determined by the area determining means to which the ship is directed, based on the compass azimuth angle and the compass azimuth angle;
storage means for storing the coefficients acquired by the coefficient acquisition means for each of the regions;
correction means for correcting the compass azimuth based on the coefficients stored by the storage means;
a comparing means for comparing the coefficient already stored in the region with the newly obtained coefficient when the coefficient is newly obtained in the region of 1 by the coefficient obtaining means;
if the difference between the already stored coefficient compared by the comparing means and the newly found coefficient is within a specific range, deleting the already stored coefficient from the storage means, The newly obtained coefficient is stored in the storage means as the coefficient of the area, and if the difference between the coefficient already stored in the area and the newly obtained coefficient is not within a specific range, and update means for deleting from said storage means the coefficients of all said regions that have already been stored. position information acquisition means for acquiring position information based on radio waves from satellites;
Compass azimuth acquisition means for acquiring the compass azimuth angle transmitted by a magnetic compass mounted on a ship and outputting a compass azimuth angle determined based on geomagnetism;
display means for displaying the position of the ship based on the position information obtained by the position information obtaining means, and displaying the direction of the ship based on the compass bearing angle obtained by the compass bearing angle obtaining means; A plotter comprising
An area for determining the area including the azimuth angle of the direction of the ship based on the compass azimuth angle obtained by the compass azimuth acquisition means by dividing the entire azimuth area centering on the hull of the ship into a plurality of areas. means of judgment;
A moving azimuth angle obtaining means for obtaining a moving azimuth angle obtained from the temporal change of the position information;
When a period in which the moving speed of the ship is equal to or higher than a predetermined speed continues for a predetermined period, the moving azimuth obtained by the moving azimuth obtaining means and the compass azimuth obtained by the compass azimuth obtaining means during the predetermined period of time. a coefficient acquiring means for acquiring a correction coefficient used for correcting the compass azimuth angle in the area determined by the area determining means to which the ship is directed, based on the compass azimuth angle and the compass azimuth angle;
storage means for storing the coefficients acquired by the coefficient acquisition means for each of the regions;
correction means for correcting the compass azimuth based on the coefficients stored by the storage means;
The coefficient for each region stored in the storage means is the coefficient obtained in one orientation included in the region,
The plotter is
interpolating between the coefficients of the first region and the coefficients of the second region stored by the storage means, and obtaining the direction from which the coefficients of the first region are obtained and the coefficients of the second region; an interpolating means for obtaining the coefficients in the azimuths sandwiched between the azimuths that
interpolation storage means for storing, for each direction, the coefficients in directions interposed between the direction from which the coefficients of the first region obtained by the interpolation means and the direction of obtaining the coefficients of the second region are obtained; A plotter comprising: The coefficient obtaining means obtains a plurality of differences between the moving azimuth angle and the compass azimuth angle at the same time during the predetermined period in which the ship moves at the predetermined speed or more, and calculates the difference at each time during the predetermined period. 5. The plotter according to claim 1, wherein the coefficient is obtained by averaging . 6. The plotter according to any one of claims 1 to 5, wherein said coefficient obtaining means obtains said coefficient when the moving speed of said ship changes from being lower than said predetermined speed to being equal to or higher than said predetermined speed. . 7. The plotter according to any one of claims 1 to 6, wherein said coefficient acquisition means acquires said coefficient when the moving speed of said ship first exceeds said predetermined speed after power is turned on.

Images