KR100535377B1 - Apparatus of image displaying used for ship having function of simultaneously displaying ship location information in two coordinate system - Google Patents

Abstract

The present invention relates to an image display apparatus for ships capable of simultaneously displaying the ship position by two coordinate systems. According to an aspect of the present invention, there is provided a ship image display apparatus comprising: a GPS signal receiver configured to receive a GPS signal from a GPS satellite and output a first position coordinate of a ship according to a first coordinate system set by a user; A coordinate system converter that receives the first position coordinates output from the GPS signal receiver, calculates a second position coordinate of a ship according to a second coordinate system set by a user, and outputs a first position coordinate and a second position coordinate; After reading the chart from the memory in which the chart is stored, the video controller is controlled to display a chart of a predetermined range on the image display centered on a point corresponding to the first position coordinate or the second position coordinate, and the predetermined area of the image display unit. And a main microprocessor for controlling the process such that the first position coordinates and the second position coordinates are simultaneously output.

Description

Apparatus of image displaying used for ship having function of simultaneously displaying ship location information in two coordinate system}

The present invention relates to a ship navigation image display device that digitally outputs the sea chart of a ship navigation area by using a GPS (Global Positioning System), and more specifically, the position of the ship anticipation point in two different coordinate systems. The present invention relates to a ship navigation video display device equipped with a display function.

In general, a GPS navigation plotter is a GPS plotter that acquires GPS coordinates of a sailing vessel in real time and displays the position of the vessel in real time on a chart of a sailing region stored in a memory. Since the GPS plotter displays the GPS reception coordinates on the chart of the ship navigation area stored in the memory, the ship navigator can identify the ship's position in real time and is considered to be an essential equipment when sailing the ship.

On the other hand, the ship image display apparatus according to the prior art displays only the position information according to one coordinate system when displaying the current position of the vessel on the chart. Currently, the number of major standard coordinate systems that can be used for ship video display device is about 85, and almost all countries apply World Geodetic System (WGS) -84 coordinate system to ship video display device.

The WGS-84 coordinate system is an earth-based global fixed coordinate system created in 1984 based on the earth's gravitational field and the shape of the earth, which has been measured worldwide using GPS and other measuring instruments. The Z axis of the WGS-84 coordinates is parallel to the direction of the Earth's rotation axis as defined by Bureau International Le L'herue in 1984, and the X axis is the intersection of the reference meridion plane and the equator plane of the WGS-84. It is parallel to the zero meridian defined by the International Times Board with respect to the longitude coordinates adopted by the International Times Stations. The Y axis is defined as a direction perpendicular to the east of the plane formed by the X axis and the Y axis.

By the way, there is a country that uses the WGS-84 coordinate system and other standard coordinate system as described above for the video display device for ships, which causes problems in territorial sea invasion of other countries or departure of fishery area during voyage or operation at sea. It is occurring.

For example, since April 2002, Japan has used the WGS-84 coordinate system as the standard coordinate system for ship video display devices, but before that, the Tokyo coordinate system has been used as the standard coordinate system for ship video display devices. Most ships still use image display devices for ships with Tokyo coordinate system. As a result, ships sailing and operating in offshore waters have concerns about the invasion of territorial seas and exclusive economic zones due to the application of position (latitude and longitude) values by different coordinate systems between neighboring countries. Accordingly, in the case of South Korea, as in Japan, the coordinate system applied to the video display device for ships is changing from the Tokyo coordinate system to the WGS-84 coordinate system.

However, it would be costly and time-consuming to replace the device with a ship video display device using the WGS-84 coordinate system, especially in the case of Korea, so far, the ship video display device and the WGS-84 coordinate system according to the Tokyo coordinate system are still present. According to the ship video display device is bound to be mixed. In this case, the position (latitude and longitude) value error between the ship image display device using the WGS-84 coordinate system and the ship image display device using the existing Tokyo coordinate system may be changed. Errors may occur, which may cause problems such as the infringement of the territorial sea and the exclusive economic zone of the neighboring countries described above.

The present invention has been conceived to overcome the above-mentioned problems of the prior art, and at the same time, an error occurs when exchanging position information between ships by simultaneously providing ship position information according to two different coordinate systems to a ship navigator in a ship video display device. To solve problems such as territorial waters in neighboring countries or invasion of exclusive economic zones.

According to an aspect of the present invention, there is provided a ship image display apparatus comprising: a GPS signal receiver configured to receive a GPS signal from a GPS satellite and output a first position coordinate of a ship according to a first coordinate system set by a user; A coordinate system converter that receives the first position coordinates output from the GPS signal receiver, calculates a second position coordinate of a ship according to a second coordinate system set by a user, and outputs a first position coordinate and a second position coordinate; And after reading the chart from the memory in which the chart is stored, controlling the video controller so that a chart of a predetermined range is displayed on an image display centering on a point corresponding to the first position coordinate or the second position coordinate. And a main microprocessor for controlling the process such that the first position coordinates and the second position coordinates are simultaneously output to a region.

In the present invention, the coordinate system converter, the first interface for interfacing the data input and output with the GPS signal receiver; A second interface for interfacing data input / output with the main microprocessor; Datum of the ellipsoid adopted by a plurality of coordinate systems, an algorithm for converting the upper and the longitude coordinates to the center coordinates in each ellipsoid, the necessary parameter values, the necessary parameter values for the transformation of the center coordinates between the ellipsoids, and the center coordinates in each ellipsoid, A memory unit for storing arithmetic algorithm and necessary parameter values for converting into longitude coordinates; And a coordinate system conversion processor for converting the first position coordinates according to the first coordinate system of the ship into the second position coordinates according to the second coordinate system with reference to the memory unit.

In the present invention, it is preferable that the main microprocessor provides a video display with a coordinate system selection interface for selecting and receiving type information of the first coordinate system and the second coordinate system from the user in response to a user's request.

The video display device for ships according to the present invention is provided with a button for selecting a predetermined coordinate system as a first coordinate system or a second coordinate system on the coordinate system selection interface, and a keypad for transmitting a coordinate system selection signal by a user to the main microprocessor. It is preferable to further include. In this case, when the first coordinate system selection signal is received from the keypad, the main microprocessor transmits the selected first coordinate system type information to the processor of the GPS signal receiver and the coordinate system converter. The type information of the first coordinate system may be stored and stored in the memory. When the second coordinate system selection signal is received from the keypad, the microprocessor transmits the selected second coordinate system type information to the processor of the coordinate system converter, and the processor of the coordinate system converter transmits the second coordinate system type information to its own memory. Can be stored.

In the present invention, the first coordinate system and the second coordinate system may be a WGS-84 coordinate system and a Tokyo coordinate system, respectively, and on the contrary, the first coordinate system and the second coordinate system may be a Tokyo coordinate system and a WGS-84 coordinate system, respectively.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

1 is a device configuration diagram showing the configuration of a ship video display device according to an embodiment of the present invention.

Referring to FIG. 1, a ship video display device according to the present invention includes a GPS signal receiver 10, a video controller 20, an image display device 30, a coordinate system converter 40, a main microprocessor 50, and a keypad 60. And a memory for storing charts 70.

The GPS signal receiver 10 receives a GPS signal from a satellite and converts the GPS signal into first position coordinates (latitude and longitude) of a first coordinate system set by a user in advance. The first coordinate system is set by the user through the keypad 60, and is preferably set as a coordinate system of a ship video display apparatus. To this end, the main microprocessor 50 displays a first coordinate system selection interface through which the user selects the type information of the first coordinate system through the image display device 30 in response to the user's request. When the first coordinate system is selected (for example, the WGS-84 coordinate system), the main microprocessor 50 receives the type information of the selected coordinate system and transmits the information to the GPS signal receiver 10 and the coordinate system converter 40. Then, the processor (not shown) of the GPS signal receiver 10 and the coordinate system converter 40 stores the type information of the first coordinate system in a separately provided memory. The GPS signal receiver 10 comprises a GPS antenna for receiving a signal and a processor for processing the signal and converting the signal into first position coordinates according to a first coordinate system determined by a user. ) Is now commercially available.

Position information of the ship output from the GSP signal receiver 10 according to the first coordinate system is input to the coordinate system converter 40, and the coordinate system converter 40 is a first position which is position information of the ship according to the inputted first coordinate system. After converting the coordinates into second position coordinates (latitude and longitude) which are position information according to the user-defined second coordinate system, two different vessel position information according to the first coordinate system and the second coordinate system are transferred to the main micro process 50. Output Here, a specific process of converting the first position coordinates according to the first coordinate system into the second position coordinates according to the second coordinate system will be described later.

The type information of the second coordinate system is directly selected by the user. To this end, the main microprocessor 50 displays the second coordinate system selection interface for allowing the user to directly select the type of the second coordinate system to the user through the image display device 30. Then, the user selects a predetermined second coordinate system from the displayed second coordinate system selection interface using the cap 60. The main microprocessor 50 receives the type information of the selected second coordinate system and transmits it to the coordinate system converter 40. In response, the processor (not shown) of the coordinate system converter 40 receives the type information of the inputted second coordinate system. Store in a separate memory.

The video controller 20 displays the sea chart read from the sea island storage memory 70 according to an output signal of the main microprocessor 50 on a video display (eg, LCD) 30 in a graphic interface. GPS coordinates indicating the position are centered on the screen, and the chart of the predetermined range is displayed as an image based on the center. This process is of course controlled by the main microprocessor 50. In addition, when the main microprocessor 50 outputs the position information of the ship according to the first coordinate system and the second coordinate system, the video controller 20 may display the first position coordinates in a predetermined screen area provided on the image display device 30. Simultaneously output the second position coordinates to the graphical interface. The first position coordinates and the second position coordinates, which are position information of the ship according to the first coordinate system and the second coordinate system, are latitude and longitude according to the corresponding coordinate system.

The keypad 60 is provided with a plurality of buttons, for example, a numeric key, a direction movement key, a selection confirmation key, a selection cancel key, and the like, which can give a control command to the image display apparatus for ships according to the present invention. In the present invention, the user selects the type of the first coordinate system and the second coordinate system using the keypad 60 and inputs the selected coordinate system information to the main microprocessor 50. Type information of the first coordinate system and the second coordinate system input to the main microprocessor 50 is transmitted to the GPS signal receiver 10 or the coordinate system converter 40 as described above.

2 is a block diagram showing in more detail the configuration of the coordinate system transducer 40 provided in the ship image display apparatus according to the present invention.

Referring to FIG. 2, the coordinate system converter 40 includes a system operation processor 80, a coordinate system conversion processor 90, a first interface 100 forming a data input / output interface with the GPS signal receiver 10, and a main microcomputer. A second interface 110 forming a data input / output interface with the processor 50 is included.

In addition, the coordinate system converter 40 includes: a first memory 120a in which a system operating program of the coordinate system converter 40 is stored; For each of the plurality of coordinate systems, the calculation algorithm and necessary parameter values for transforming the centroid coordinates between two ellipsoids employed by each coordinate system, and the coordinates of the ellipsoids employed by each coordinate system, and the coordinate system is adopted for each coordinate system. A second memory (120b) for storing a calculation algorithm and necessary parameter values for conversion between latitude and longitude coordinates and geocentric coordinates in an ellipsoid; The memory unit 120 includes a third memory 120c that stores information stored in the first coordinate system and the second coordinate system type information selected and input from the main microprocessor 50.

The system operation processor 80 loads the system operation program stored in the first memory 120a when the power is applied to the ship image display apparatus according to the present invention, initializes the coordinate system converter 40, and executes the third memory 120c. Read the type information of the first coordinate system and the second coordinate system recorded in the) and transmits the information to the coordinate system conversion processor (90). Then, the coordinate system conversion processor 90 needs a computational algorithm capable of converting the position information of the ship from the first coordinate system to the second coordinate system in the second memory 120b (first position coordinate-> second position coordinate). The factor value is read and loaded into the working memory (not shown), and upon request from the main microprocessor 50, the first position coordinates of the ship according to the first coordinate system input from the GPS signal receiver 10 are converted into the second coordinate system. And converts the first position coordinates and the second position coordinates to the main microprocessor 50.

Then, the main microprocessor 50 controls the video controller 20 to display the first position coordinates and the second position coordinates, which are position information of the ship according to the first coordinate system and the second coordinate system, on the image display device 30. Allows display in real time on the screen area.

Accordingly, since the ship navigator can grasp the current ship position at the same time by different coordinate systems, there is an error in the position information when the position information is exchanged between ships using the ship video display device to which the different coordinate systems are applied as in the prior art. It can be prevented from occurring and further prevented the invasion of territorial waters or exclusive economic zones between neighboring countries.

Hereinafter, after the coordinate system converter 40 according to the present invention loads the calculation algorithm and necessary parameter values for the coordinate system conversion necessary in the second memory 120b into the working memory, the coordinates of the first position of the ship according to the first coordinate system are set. A process of converting the vessel into the second position coordinates according to the two coordinate system will be described in more detail. For convenience of explanation, assume that the first coordinate system is the WGS-84 coordinate system and the second coordinate system is the Tokyo coordinate system. The transformation of the coordinate system is performed by first converting the latitude and longitude coordinates according to one coordinate system into three-dimensional centroid coordinates of the earth ellipsoid employed by the coordinate system, and then again employing another ellipsoid adopted by another coordinate system to convert the centroid coordinates converted into the first order. Secondary transformation into centroid coordinates of, and second-order transformation of the centrifugal transformation of the centroid transformed into upper and longitude values of the earth ellipsoid are performed.

① Convert longitude and latitude coordinates of the first coordinate system to centroid coordinates

 The coordinate system conversion processor 90 of the coordinate system converter 40 converts the first position coordinates (longitude, latitude) according to the first coordinate system into centroid coordinates by applying Equation 1 below. Here, the first position coordinates are input from the GPS signal receiver 10 to the coordinate system converter 40 through the first interface 100.

X = (N + H) × cosΦ × cosθ

Y = (N + H) × cosΦ × cosθ

Z = {N × (1-e ² ) + H} × sinΦ

N = a / root {1-e ² × (sinΦ) ² }

In Equation 1, 'Φ' is the latitude according to the first coordinate system, 'θ' is the longitude according to the first coordinate system, 'a' is the long radius of the ellipsoid adopted by the first coordinate system, and 'e' is the The eccentricity of the ellipsoid adopted by the one coordinate system, H is the height of the ellipsoid adopted by the first coordinate system, and N is the radius of lateral curvature of the ellipsoid employed by the first coordinate system. As such, each parameter value defining the earth ellipsoid employed by the coordinate system may be collectively referred to as a datum of the ellipsoid, which is natural to those skilled in the art.

② Convert centroid coordinates according to the first coordinate system to centroid coordinates according to the second coordinate system

The coordinate system conversion processor 90 of the coordinate system converter 40 converts the centroid coordinates according to the first coordinate system into the centroid coordinates of the ellipsoid adopted by the second coordinate system by applying Equation 2 below. In this case, seven factors are required for the transformation of the centroid coordinates between ellipsoids adopted by each coordinate system, and each factor represents Tx, Ty, Tz, X, Y, It consists of ω (omega), Φ (phi), κ (kappa), which are rotational movements about the Z axis, and S, which is a scale factor between ellipsoids. These parameters are determined differently according to pairs of coordinate systems which are transformed with each other, which is well known to those skilled in the art to which the present invention belongs.

| Xb | = | Tx | | 1 κ -Φ | | Xw |

| Yb | = | Ty | + (1 + S) | -κ 1 ω | | Yw |

| Zb | = | Tz | | Φ -ω 1 | | Zw |

| | Determinant

In Equation 2, Xw, Yw, and Zw represent center coordinates according to the WGS-84 coordinate system, which is the first coordinate system, and Xb, Yb, and Zb represent center coordinates according to the Tokyo coordinate system, which is the second coordinate system, and the rotational movement amount is radians. (radian).

If the first coordinate system is the Tokyo coordinate system and the second coordinate system is the WGS-84 coordinate system, Equation 2 above is transformed to Equation 3 below.

| Xw | = | Tx | | 1 κ + Φ | | Xb |

| Yw | = | Ty | -(1-S) | + κ 1 ω | | Yb |

| Zw | = | Tz | | Φ + ω 1 | | Zb |

| | Determinant

In Equation 3, Xw, Yw, and Zw represent center coordinates according to the WGS-84 coordinate system, which is the second coordinate system, and Xb, Yb, Zb represent center coordinates according to the Tokyo coordinate system, which is the first coordinate system, and the rotational movement amount is radians. (radian).

③ Convert the centroid coordinates of the second coordinate system calculated by Equation 2 to upper and longitude coordinate values.

The coordinate system conversion processor 70 of the coordinate system converter 40 converts the centroid coordinates according to the second coordinate system into upper and longitude coordinate values of the second coordinate system by applying Equation 4 below.

Hardness (θ) = tan ^-1 (Y / X)

Ellipsoid height (H) = (P / cos Φ)-N

Where P = root (X ² + Y ² ),

_{N (i-1) = a} / (root (1-e 2 × sin (Φ (i-1)) 2) , and the constraints of φ _{is, φ (n) - ≤ 10} φ (n-1) - ¹² (radian) and Φ ₍₀₎ = tan ^-1 (Z / P), that is, the initial value of Φ is the value of Φ ₍₀₎ of the above constraints, and continues by substituting this value for latitude. If the difference between the latitude value (i-th) and the latitude value (i-1) previously obtained is less than or equal to 10 ^-12 rad, select the latitude value of the second coordinate system. .

When the coordinate system conversion processor 90 of the coordinate system converter 40 performs the series of calculations according to the above-described ① to ③, the first position coordinates (latitude and longitude) of the ship according to the first coordinate system are determined according to the second coordinate system. When the coordinates are converted to the second position coordinates (latitude and longitude) of the vessel, and the coordinate transformation process is completed, the coordinate system conversion processor 90 transmits the position coordinates of the vessel according to the first coordinate system and the second coordinate system to the main microprocessor 50. do. Then, as described above, the main microprocessor 50 reads the chart of the area corresponding to where the ship is currently located in the chart storage memory 70 at a predetermined coordinate range and transmits the chart to the video display device 20 through the video controller 20. 30 and display the first position coordinates and the second position coordinates of the ship according to the first coordinate system and the second coordinate system input from the coordinate system converter 40 on a predetermined screen area provided on the image display device 30. Done.

The coordinate conversion process as described above is repeated every time the position coordinates of the ship according to the first coordinate system set by the user from the GPS signal receiver 10 is input. The first position coordinates and the second position of the vessel according to the first coordinate system and the second coordinate system, which are output to the image display device 30 in response to a period in which the position coordinates of the vessel according to the first coordinate system are output by the GPS signal receiver 10. Coordinates are also updated in real time. Accordingly, the ship navigator is provided with the advantage of simultaneously grasping the sailing position of the current ship in two different coordinate systems, thereby solving the problems of the prior art described above.

In the above, an embodiment of the present invention has been described with reference to a process of converting ship position information between a WGS-84 coordinate system and a Tokyo coordinate system. However, the technical idea of the present invention is to convert ship position coordinates between various types of standard coordinate systems as shown in Table 1 below. Applicable to those skilled in the art is naturally applicable.

number Coordinate system name number Coordinate system name 0 WGS-84 43 CHATHAM One WGS-72 44 PAPAGUAY 2 TOKYO 45 BRAZIL 3 NAD-27 46 NEW GEORGIA 4 ALASKA / CANADA 47 EASTER 5 EUROPEAN 50 48 MALDIVE 6 AUSTRALIAN 84 49 GUAM 63 7 SOUTH ASIA 50 GUADAL CANAL 8 SOUTH AMERICA 51 HONG KONG 63 9 GREENLAND 52 DIEGO GARCIA 10 NAD-83 53 JOHNSTON 11 ICELAND 55 54 SRI LANKA 12 IRELAND 65 55 KELGUELEN 13 NEW ZEALAND 56 CAYMAN BRAC 14 EUROPEAN 79 57 LIBERIA 64 15 ROME 40 58 MAHA 71 16 SOUTH AFRICA 59 SALVAGE 17 SAUDI ARABIA 60 ERITREA 18 INDIAN / NEPAL 61 MOROCCO 19 PHILLIPPINES 62 MIDWAY 61 20 ENGLAND 63 NIGERIA 21 HAWAII 64 TRINDAD 22 DJAKARTA 65 CORVO / FLORES 23 MALAYSIA 66 EGYPT 24 JAPAN 67 OMAN 25 ETHIOPIA 68 CANARY 26 SOMALIA 69 PITCAIRN 27 BAHRAIN 70 SOUTH CHILE 28 COCOS 71 PUERTO RICO 29 ARC 50 72 QATAR 30 ARC 60 73 MASCARENE 31 ASCENSION 74 SANTO 32 IWO JIMA 75 SANTA MARIA 33 TERN 76 EAST FALKLAND 34 ST.HELENA 77 PORTO SANTO 35 MARCUS 78 FAIAL 36 EFATE 79 EAST MALAYSIA 37 BERMUDA 80 TRISTAN 38 COLOMBIA 81 FIJI 39 ARGENTINA 82 MARSHALL 40 PHOENIX 83 SURINAM 41 FLORIDA 84 FINLAND 42 TUNISIA 85 SWEDEN

Although the present invention has been described above by means of limited embodiments and drawings, the present invention is not limited thereto and will be described below by the person skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of the claims.

According to the present invention, unlike the ship navigation image display device according to the prior art, it is possible to simultaneously display the ship position according to the two coordinate systems on one screen, between ships using a ship image display device employing different coordinate systems Even if the ship position information is exchanged, the error of the position information can be prevented from occurring, and further, the problem of territorial sea invasion or economic exclusive water invasion between neighboring countries using different coordinate systems can be solved.

The following drawings attached to this specification are illustrative of preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to

1 is a device configuration diagram showing the configuration of a ship video display device according to an embodiment of the present invention.

2 is a block diagram showing in more detail the configuration of a coordinate system transducer provided in the video display device for ships according to the present invention.

Claims (8)

A GPS signal receiver which receives a GPS signal from a GPS satellite and outputs first position coordinates of the ship according to a first coordinate system set by a user; A first operation algorithm for converting the datum of the ellipsoid employed by the first and second coordinate systems, the upper and longitude coordinates of the ellipsoids into the centroid coordinates, the necessary first factor values, and the second operation algorithm required for the centroid coordinate transformation A third operation algorithm for converting the center coordinates from the ellipsoid into upper and longitude coordinates, and a memory unit storing the necessary third argument values; and a memory according to the first coordinate system of the ship with reference to the memory unit. And a coordinate system conversion processor for converting one position coordinate into a second position coordinate according to a second coordinate system, and receiving first position coordinates (latitude and longitude) output from the GPS signal receiver under control of the coordinate system conversion processor. Reference to the first computational algorithm and the first argument value is converted to the geocentric coordinates according to the first coordinate system, and the second computational algorithm and the second argument value is referred to the reference coordinate system. Converting the coordinates into geocentric coordinates of the second coordinate system, and the third computation algorithm and a coordinate system converter for three-factor reference value and converts the geocentric coordinates of the second coordinate system to the second position coordinates (latitude and longitude); And After reading the chart from the memory in which the chart is stored, the video controller is controlled to display a chart of a predetermined range on the image display centered on a point corresponding to the first position coordinate or the second position coordinate, and the predetermined area of the image display unit. And a main microprocessor for controlling a process such that the first position coordinates and the second position coordinates are simultaneously output to the ship. delete The method of claim 1, The main microprocessor of the ship image display device, characterized in that to provide a coordinate system selection interface to the image display to receive the selection information of the type of the first coordinate system and the second coordinate system from the user in response to the user's request. The method of claim 3, A ship image comprising a keypad for selecting a predetermined coordinate system as a first coordinate system or a second coordinate system on the coordinate system selection interface and transmitting a coordinate system selection signal by a user to the main microprocessor. Display. The method of claim 4, wherein When the first coordinate system selection signal is received from the keypad, the main microprocessor transmits the selected first coordinate system type information to the GPS signal receiver and the processor of the coordinate system converter. And a processor of the GPS signal receiver and the coordinate system converter, storing the type information of the first coordinate system in a memory provided in the memory. The method of claim 4, wherein When the microprocessor receives the second coordinate system selection signal from the keypad, the microprocessor transmits the selected second coordinate system type information to the processor of the coordinate system converter. And a processor of the coordinate system converter, storing the second coordinate system type information in a memory provided in the memory. The method of claim 1, And wherein the first coordinate system and the second coordinate system are WGS-84 coordinate system and Tokyo coordinate system, respectively. The method of claim 1, And the first and second coordinate systems are Tokyo coordinate system and WGS-84 coordinate system, respectively.