DESC:SYSTEM, DEVICE AND METHODS FOR CONTINUOUS PLOTTING OF RELATIVE POSITIONS OF VESSELS AT SEA OR SUB-SEA LEVEL

FIELD OF THE INVENTION:

[0001] The present invention generally relates to the field of navigation for monitoring movement of vessels on a sea surface or underneath. More specifically, the present invention relates to a system for continuous plotting of relative positions of vessels at sea or sub-sea level, a device and methods thereof for general and tactical navigation functions.

BACKGROUND OF THE INVENTION:

[0002] With a planet as large as Earth, and the growing necessity of travel, it is essential to be able to effectively navigate routes in order to reach the appropriate destinations. Navigation is a field of study that focuses on the process of monitoring and controlling movement of a craft or vessel in sea, from one place to another. Accurately assessing a position of a vessel has been a problem which has been faced by travelers throughout the world.

[0003] During the ancient times, positions were derived from the location and angle of celestial bodies using telescopes and sextants. Ascertaining the location by way of the conventional methods requires one to have a thorough knowledge of the celestial bodies and methods of reading their positions. Subsequently, the same were cross-referenced in order to obtain the position of the platform. However, such methods rely heavily on the knowledge of the individual and are prone to a multitude of errors. At the same time, such methods offer no advantage in navigating the position of other neighbouring vessels.

[0004] The above issues were not only faced by land travelers but also seafarers who would often lose their way, due to unfavourable weather conditions at sea. After the invention of gyro-compass and speed measuring devices; it was possible to obtain the direction and speed of movement of a vessel, thereby deriving the latitude and longitude coordinates of the vessel on earth’s surface. Moreover, as time progressed, a better knowledge of Earth’s geography led to generation of paper-based tools of Earth, to assist mariner’s all over the world. One such tool is known as a nautical chart on which the position of the vessel could be manually plotted.

[0005] Gradually, with the advancement of technology and automation, the interest to undertake the plotting activity in automatic fashion gained importance, thereby leading to the design of plotting tables, which assisted people in navigating through the enormous water bodies. However, such plotting tables resulted in various new challenges, and more pertinently, the accuracy of geographical plotting. Although automated plotting has become reality, the challenge to improve the accuracy of plotting still remains. Further, the need to provide various tools for solving the relative velocity problems of two or more vessels at sea in near vicinity to avoid collision has also arisen.

[0006] Due to the underlying issues being faced with the traditional plotting tables, there is a need to indigenously conceptualize, design, fabricate, validate and develop devices like an auto-plotter to provide a reliable and efficient plotting tool which proves to be an effective import substitution for critical equipment to enhance fighting capability of warships and which would in turn address variety of issues including, but not limited to, improved accuracy of positioning for functional correctness and precise position marking and to solve the relative velocity problems of one or more vessels.

[0007] Thus, the above-described deficiencies of conventional approaches, screening procedures and methods thereof, are merely intended to provide an overview of some of the problems of conventional approaches and are not intended to be exhaustive. Other problems with conventional approaches, and methods and their corresponding benefits of the various non-limiting embodiments described herein may become further apparent upon review of the following description.

SUMMARY OF THE INVENTION:

[0008] The following presents a simplified summary of the invention to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

[0009] It is, therefore, an object of the present invention to provide an indigenous system for continuous plotting of relative positions of vessels, that is, own vessel and other vessels at sea or sub-sea level which performs without any operator intervention once configured at the beginning of a voyage. The system in view of the foregoing disadvantages inherent in the prior-art, the general purpose of the present invention is to provide a system for continuous plotting of relative positions of vessels at sea or sub-sea level that is capable of including all advantages of the prior art and also overcomes the drawbacks inherent in the prior art offering some added advantages.

[0010] It is another object of the present invention to provide a system which facilitates visual identification of neighbouring vessels in proximity.

[0011] It is another object of the present invention to provide a system which raises an error alarms upon sensor data error, communication error, drive motor error, or combinations thereof.

[0012] It is another object of the present invention to provide a system which is used to track replay and predict future position of own vessel and other vessels in proximity based on current course and speed of the vessel.

[0013] It is another object of the present invention to provide a system which operates in harsh conditions and capable of bearing shock and vibration experienced by the platform during the operation.

[0014] It is another object of the present invention to provide a device for accurate and continuous plotting of relative positions of vessels, that is, own vessel and other vessels at sea or sub-sea level during day and night and which is easy to operate.

[0015] It is yet another object of the present invention to provide a method for an accurate continuous plotting of relative positions of vessels, that is, own vessel and other vessels at sea or sub-sea levels on a nautical chart.

[0016] It is yet another object of the present invention to provide a method for chart referencing in order to automatically confirm the chart scale for accurate and continuous plotting of relative positions of vessels at sea or sub-sea levels.

[0017] It is yet another object of the present invention to provide a method for continuous plotting of positions of a specific vessel and relative position of a target vessel over a plain sheet.

[0018] It is yet another object of the present invention to provide a method of detection and correction of skew in a nautical chart placement, enabling an accurate continuous plotting of relative positions of vessels at sea or sub-sea levels on the nautical chart.

[0019] It is yet another object of the present invention to provide a method for activating anti-collision alarm based on relative positions of vessels, that is, own vessel and other vessels at sea or sub-sea level, being plotted on a nautical chart.

[0020] It is yet another object of the present invention to provide a method for determining a true motion of a target vessel at sea or sub-sea level.

[0021] It is still another object of the present invention to provide a method for classifying target vessels.

[0022] It is yet another object of the present invention to provide a method for determining a man overboard position and defining a course to reach said position.

[0023] Accordingly, in an aspect, the present invention provides a system for continuous plotting of relative positions of vessels, that is, own vessel and other vessels at sea or sub-sea level on a nautical chart, comprising of a device having an X-Y gantry, a control unit and a display unit. The device is configured with a nautical chart and has a carriage assembly configured to have cross arms and an illuminated crosshair mounted on the cross arms, a first stepper motor and a second stepper motor configured to drive the cross arms of the carriage assembly. The control unit is operationally coupled with the device and a display unit has an interactive user interface and is also configured electronically with the control unit and the device. The first stepper motor imparts one of the cross arms a linear motion in an X-axis and the second stepper motor imparts other cross arm a linear motion in Y-axis. The control unit resolves motion data received from a plurality of sensors of the vessels into motion vectors which thereby being converted into a signal for driving the cross arms in X axis and Y-axis. Further, the movement of the cross arms in X-axis and Y-axis enables movement of the illuminated cross hair mounted on the cross arms thereby allowing continuous plotting of relative positions of the vessels at sea or sub-sea level.

[0024] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, details the invention in different embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0025] While the specification concludes with claims that particularly point out and distinctly claim the invention, it is believed that the advantages and features of the present invention will become better understood with reference to the following more detailed description of expressly disclosed exemplary embodiments taken in conjunction with the accompanying drawings. The drawings and detailed description which follow are intended to be merely illustrative of the expressly disclosed exemplary embodiments and are not intended to limit the scope of the present invention as set forth in the appended claims. In the drawings:

[0026] FIG. 1 illustrates a system for continuous plotting of relative positions of vessels at sea or sub-sea level in accordance with an embodiment of the present invention;

[0027] FIG. 2 illustrates(a) a device of the system in closed form; and (b) a device of the system in open form, in accordance with an embodiment of the present invention;

[0028] FIG. 3 illustrates an exploded view of an X-Y gantry to the device of the system in accordance with an embodiment of the present invention;

[0029] FIG. 4 illustrates a control unit of the system in accordance with an embodiment of the present invention; and

[0030] FIG. 5 illustrates a display unit of the system in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION:

CALL OUT LIST
1000 System
100 device
110 X-Y gantry
112 carriage assembly
102a, 102b cross arms
104 illuminated crosshair
114 first stepper motor
116 second stepper motor
118 keyboard
119 trackball
120 nautical chart
130 housing
200 control unit
300 display unit

[0031] The exemplary embodiments described herein detail for illustrative purposes are subject to many variations in the structure and design. It should be emphasized, however, that the present invention is not limited to a particular system as shown and described herein. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

[0032] The use of terms “including,” “comprising,” or “having” and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

[0033] Further, the terms, “an” and “a” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

[0034] Referring to FIG. 1, the invention will now be described in more detail. A system (1000) for continuous plotting of relative positions of vessels at sea or sub-sea level, as shown in FIG. 1, comprises a device (100), a control unit(200) and a display unit (300).The system (1000) enables the continuous and real-time plotting of the current and relative positions of the vessels such as, own vessel or other vessels.

[0035] In accordance with an embodiment of the present invention, the device (100), as shown in FIG. 1 and FIG. 2(a) and (b), has an X-Y gantry (110) which is configured with a nautical chart (120). The nautical chart (120) is a paper nautical chart. The X-Y gantry (110), as shown in FIG. 3, comprises of a carriage assembly (112), a first stepper motor (114) and a second stepper motor (116). The carriage assembly (112) has cross arms (102a, 102b), particularly two cross arms, and a crosshair (104) mounted on the cross arms (102a). The two cross arms (102a, 102b) move perpendicular to each other while maintaining absolute linearity. The cross arms (102a, 102b) of the X-Y gantry (110) are moved with the help of the first stepper motor (114) and the second stepper motor (116). Further, the first stepper motor (114) and the second stepper motor (116) are the high precision stepper motors. More specifically, the first stepper motor (114) imparts one of the cross arms (102a) a linear motion in an X-axis and the second stepper motor (116) imparts other cross arm (102b) a linear motion in Y-axis. The cross arms (102a, 102b) of the X-Y gantry (110) move at a distance proportional to X and Y motion vectors. Further, the crosshair (104), in particular, a lighted crosshair (104) mounted on the cross arms (102a), moves due to the resultant motion of the two cross arms (102a, 102b) in X-axis and Y-axis. Further, the crosshair (104) is multi-coloured and is configured for visual identification of a specific vessel and other vessels in proximity.

[0036] In accordance with an embodiment of the present invention, the X-Y gantry (110) further comprises a keyboard (118) with Fixed Function Keys (FFK) which are configured for user interaction.

[0037] In accordance with an embodiment of the present invention, the control unit (200) is operationally coupled with the device (100). The control unit (200) resolves motion data received from a plurality of sensors of the vessels into motion vectors which thereby being converted into a signal for driving the cross arms (102a, 102b) in X-axis and Y-axis. In particular, the signal is used to drive the first stepper motor (114) and the second stepper motor (116) which in turn drives the cross arms (102a, 102b) in X-axis and Y-axis. The plurality of sensors are navigational sensors selected from, but not limited to, a group consisting of motion sensors, rotation sensors, magnetic sensors, and tactical sensors. Further, the motion sensors are selected from, but not limited to, a group consisting of Gyro Compass, Log, Data Distribution Unit and global positioning system (GPS); and the tactical sensors are selected from, but not limited to, a group consisting of Radar, Sonar and Periscope.

[0038] In accordance with an embodiment of the present invention, the control unit (200), as shown in FIG. 4, comprises a processor, a power supply unit, and a module. The control unit (200) houses an inbuilt NMEA 0183 interface on RS 422 for receiving external sensor information namely Gyro, Log and GPS. Further, the operation of the control unit (200) and X-Y gantry (110) is controlled by the module. The control unit (200) receives motion data and tactical data from the plurality of sensors equipped on the vessels, and resolves the same into the motion vectors, which thereby is converted into the signal for the first stepper motor (114) and the second stepper motor (116). Further, the first stepper motor (114) and the second stepper motor (116) impart motion to the cross arms (102a, 102b) in X-axis and Y-axis, respectively. The movement of the cross arms (102a,102b) in X-axis and Y-axis enables the movement of the crosshair (104) mounted on the cross arms (102a), such that the crosshair (104) projects on to the nautical chart (120), enabling an accurate and continuous plotting of relative positions of the vessels at sea or sub-sea level on the nautical chart (120).

[0039] In accordance with an embodiment of the present invention, the control unit (200) of the system (1000) is configured to derive input data from the onboard navigational sensors such as logistics data derived from the vessel’s gyroscope and speedometer, or motion sensors fitted on the vessel or a global positioning system or the like.

[0040] In accordance with an embodiment of the present invention, the module is configured to receive motion sensor data from Gyro Compass, Log, Data Distribution Unit and GPS in serial format. Further, the motion sensor data may be received in serial Ethernet, MIL 1553 and Data Bus format. The module is configured to receive tactical sensor data from Radar, Sonar and Periscope.

[0041] In accordance with an embodiment of the present invention, the module of the control unit (200) is configured to automatically correct skew in placement of the nautical chart (120). The module is configured to automatically derive scale of the nautical chart (120) based on two point referencing or three point referencing technique. The module also operates when course and speed of the vessels are fed manually by a user or an operator. The module is also configured for route planning and creation of waypoints. Further, the module is configured to track replay and predict future position of a specific vessel and other vessels in proximity based on current course and speed of the specific vessel. The specific vessel includes the current vessel or current ship on which the system (1000) is installed and the other vessels in proximity include the neighbouring or target vessels. Furthermore, the vessel comprises watercrafts such as, but not limited to, ships or submarines.

[0042] In accordance with an embodiment of the present invention, the module is configured to raise error alarms upon sensor data error, communication error, drive motor error, or combinations thereof. Further, the module is configured to record a position of man overboard (MOB) and continuously display a course to steer to reach the position of the man overboard (MOB). The module is also configured to compute relative velocity and depict Closet Point of Approach (CPA) and Time to reach Closet Point of Approach (TCPA). The module is also configured to compute Target Motion Analysis (TMA) using Doppler-Bearing tracking method. This is a method to observe the dominant tonal frequency and observe its variation which is proportional to the closing or opening speed. Furthermore, the module is configured to compute Target Motion Analysis (TMA) using Range and Bearing received from sonar. The module is also configured to compute General Operating Plot (GOP).

[0043] In accordance with an embodiment of the present invention, the module comprise of various features for deriving the vector components of motion along the longitudinal and latitudinal axes from either the motion components (speed and heading) or the position (latitude and longitude). Further, the modules also include the relative velocity computation features, distance and time computation or the like, as per the requirement. Further, the module has been certified to IEEE 12207 Standard.

[0044] In accordance with an embodiment of the present invention, the system (1000) may be operated on various modes based on the sensors equipped and the mode selected on the display unit (300) including, but not limited to, GPS mode, Log or Gyro mode, DR more, Waypoint mode, Track mode, Man overboard mode, History or Future mode or Diagnostic Mode. The operation based on various modes are as follows:
(a) GPS Mode: In this mode, the crosshair (104) moves to the longitude and latitude coordinates provided by the GPS.
(b) Log/Gyro Mode: In this mode, the GPS data is ignored. The crosshair (104) moves proportional to the heading and speed indicated by the vessel’s gyro and Log, respectively.
(c) DR Mode: In this case, the course and speed are fed manually, and the crosshair (104) moves proportionally. Sensor data is either not available or not reliable.
(d) Waypoint Mode: This mode is used for route planning and creation of waypoints. Upto14 waypoints can be created.
(e) Track Mode: This mode is used for creation or manual contacts. Upto 50 contacts can be created.
(f) Man Overboard Mode: This mode is used to record the position of man overboard.
(g) History/Future Mode: This mode is used for track replay and predicted future position of own vessel and neighbouring vessels based on current course and speed.
(h) Diagnostic Mode: In this mode, error alarms for sensor data error, communication error and drive motor error can be raised.

[0045] In accordance with an embodiment of the present invention, the module of the system (1000) is configured to perform various Additional Special functions to assist the user as shown in error condition such as ‘Error! Reference source not found’ condition. These function keys are placed at the screen of the display unit (300). For example, the three additional special functions are provided. By default, the Special Function ‘Big Font’ (1) is always displayed. This is used to show the current input value by the user. The Special Function ‘TrkFn’ (2) stands for Track Functions such as “Posn TRK 1 using TrackBall”, “Delete TRK 1” and “Rename TRK 1”(where 1 is the Trk number). The Special Function ‘Marker’ (3) stands for Marker, which helps the user to find the range and bearing of any point on the chart with respect to current vessel or any track.

[0046] In accordance with an embodiment of the present invention, the display unit (300) is electronically configured with the control unit (200) and the device (100), as shown in FIG. 1 and FIG. 5. The display unit (300) has an interactive user interface displaying the chart properties including, but not limited to, scale, latitude and longitude, and mode selection. The interactive user interface has a plurality of user access options which are configured to provide an access to graphical content relating to a plurality of functions. The user interface coordinates with the device (100) by two means, namely, the keyboard (118) or trackball (119) installed on the X-Y gantry (110) and the remote monitor of the display unit (300). The display unit (300) may be mounted on a vertical surface in front of the X-Y gantry (110), at a distance such that the parameters are visible to the operator.

[0047] In accordance with an embodiment of the present invention, the trackball (119) is configured such that the trackball (119) can seamlessly be shifted from the analogue plotting table of the X-Y gantry (110) to the display unit (300). For example, in one instance, the trackball (119) could be pointing to a position on the horizontal transparent surface of the analogue plotting table and at the next instance the trackball (119) could be pointing to the menu selection on the display unit (300). In both the cases, there is an indication in the display unit (300) that informs where the trackball (119) is presently connected to either display unit or a LED assembly. The LED assembly is used to illuminate the crosshair (104) which is mounted on the cross arms (102a). The function selection in the X-Y gantry (110) is done using short cut keys in the keyboard (118) or using a tab selection on the screens in LCD display unit (300). All functions of the device (100) are invoked from the keyboard (118), using the trackball (119), the monitor provides ease of operation and viewing of data which is restricted while using the keyboard (118).

[0048] In accordance with an embodiment of the present invention, the interactive user interface of the display unit (300) is invoked using the trackball (119) and monitor to show various features of the screen of the display unit (300). In other words, various Multi Media Interface (MMI) screens are invoked using the trackball (119) and monitor. The MMI screen includes has six sections such as, but not limited to, (i) Current Vessel Details; (ii) System status; (iii) Alert window; (iv) Additional function window; (v) Main Screen; and (vi) Tab Selection or Function Selection. The various exemplary features displayed on the various MMI screens along with their functions are as follows:
(a) Initialize: Data integrity check. This page also facilitates ‘Auto’ and ‘Manual’ mode selection, the default being ‘Auto’;
(b) Chart Set: Chart alignment, referencing and scale computation;
(c) Tracks: Manual creation of upto50 tracks;
(d) Waypoint: Enter upto14 way points;
(e) Man Overboard: Mark man overboard position and provides course to steer;
(f) History/Future: Tabular display of for example, past 24 hrs or future 24 hrs of current vessel and tracks.

[0049] In accordance with an embodiment of the present invention, the various MMI screens facilitate interaction of the operator with the system (1000). For example, the Initialize Screen permits the user or the operator to carry out the activities, such as, but not limited to:
a) User has the facility to make the mode selection;
b) In case of sensor non-availability, user is allowed to alter the following fields: current vessel’s latitude, current vessel’s longitude, Greenwich Mean Time (GMT) offset, Heading, Speed, GYRO correction, LOG correction, Drift Direction, or Drift Speed;
c) User has the facility to modify the color scheme from day to night;
d) User is allowed to change the intensity of lighted crosshair (104).

[0050] The user is allowed to press or click on an ‘Initialize’ tab at any time during the operation. This page also facilitates ‘Auto’ and ‘Manual’ mode selection, and the default being ‘Auto’ mode. The total distance is incrementally updated by the system (1000) in this page. The latitude and longitude fields are also updated by the system (1000) based on the data received from GPS. The Heading and Speed are updated from the respective sensor output values. However, these fields may also be updated by the user when in ‘Manual mode’ and the changes take place accordingly. When all the sensor data are available, the system (1000) defaults to ‘Auto’ mode. Whenever the user visits the Initialize screen page, all current parameters are updated once in their respective fields by the system (1000). Thereafter, the parameters are changed automatically, for example, every 1 minute, whereas the data are updated in a current vessel window, for example, every 4 second.

[0051] When the data from any/all of the sensors is not received, the respective sensor is shown in, for example, RED colour after an elapse of pre-defined time. Also, an alert message is displayed on an alert window. In case of GPS failure, the system (1000) carries out Dead Reckoning (DRing) and updates the position parameters based on the speed and heading values. In case of failure of Log or/and Gyro, the system (1000) continues to hold the last received/updated values. From any function, the user is allowed to visit the Initialize screen and update the course and speed values, which will be used in all functionalities after applying necessary Log and Gyro corrections. Even when all sensors are down, the system (1000) thus, continues to be in the ‘Auto’ mode, generating relevant values as described above.

[0052] In manual mode, when the sensors are not available the user is allowed to select ‘Manual’ mode and the system (1000) picks up the respective values from the Initialize Screen page. Also, in harbor, this mode can be used to train the crew, without the requirement to ‘switch on’ the sensors. Further, in the manual mode, the system (1000) picks up the latitude and longitude values from the Initialize page and starts DRing, with the Speed and Course values, after applying the necessary corrections. In addition to this, the system (1000) applies Drift correction from the Drift Speed and Drift direction values. The time is updated regularly, and the total distance is cumulatively updated.

[0053] The user can also control the intensity of crosshair (104) by choosing the either of the values ‘Low’, ‘Med’, ‘High’ and the selected intensity will be applied to crosshair (104) for all the MMI screens. Further, the user can change the color scheme by moving the slider between ‘Day’ and ‘Night’ and the selected color scheme will be applied to all the MMI screens.

[0054] For example, the another screen, that is, the Chart Set Screen permits the user or the operator to carry out the activities, such as, but not limited to:
a) User has the facility to align the chart vertically;
b) User has the facility to align the chart horizontally;
c) User can do three point referencing if the chart type is Mercator;
d) User can do single point referencing if the chart type is GOP;
e) User can verify the entered reference points by pressing ‘Show Ref 1’, ‘Show Ref 2’ and ‘Show Ref 3’.

[0055] In the Chart Set Screen, the user can set the required chart and make the system (1000) indicate the correct position of the current vessel and the tracks on the chart through the LED assembly. Only if a chart is set, the user will be taken to other functionalities, even though the system (1000) in the background continues to receive, process and display the sensor values in the respective window. Further, the user can select ‘Mercator’ or ‘GOP Sheet’ under chart selection. Further, the user is expected to choose between “Ref” and “Align” functionalities. Under “Ref” functionality, the user can reference the chart as explained below. Under “Align”, the user can align the chart parallel to the X-Y gantry axes to avoid or minimize skew.

[0056] For example, the another screen, that is, the Tracks Screen permits the user or the operator to carry out the activities, such as, but not limited to:
a) Manual track can be created by entering latitude and longitude of a selected track;
b) Manual track can be created by entering bearing and range of the selected track;
c) Manual track can be created by moving the lighted crosshair (104) on chart using trackball (119);
d) Stand Off Radius (SOR) of any track or current vessel can be entered;
e) User can specify the type and class of the selected track;
f) User can move the lighted or illuminated crosshair (104) either to current vessel position or track position at Closest Point of Approach (CPA);
g) To find the intercept time, course and position, user should enter current vessel speed followed by click on ‘Find X’;
h) To switch between intercept position and track position user should click on ‘Show X’;
i) Use can change the unit of range from Nm to KYds;
j) User has the facility to rename and delete the valid track.

[0057] The user is allowed to visit the Tracks screen only if the chart referencing is completed at least once. In this screen, the user is allowed to create up to 50 manual tracks. The user cannot modify current vessels parameters such as position, course or speed from this screen page. However, the user can enter SOR in NM or K Yards. As a default, whenever the user comes to the Tracks screen page, the LED assembly is moved to a position in the chart corresponding to the current vessel’s position, with, for example, yellow colour illuminated. The system (1000) moves the LED assembly, for example, every 4 sec proportionate to the current vessel’s movement indicating the position on the nautical chart (120).

[0058] In this screen, the user is allowed to create manual track and for creating a track, the user has following options to indicate the track’s position, such as, but not limited to:
a) User can give bearing and range from the current vessel. The system (1000) calculates the latitude and longitude values and positions the track;
b) User can enter the latitude and longitude values and the system (1000) calculates the bearing and range information;
c) The user can select the option ‘Position using Mouse’. The crosshair (104) turns, for example, green colour indicating that the crosshair (104) is ready to move. The LED assembly is under the control of trackball (119). The user can move the trackball (119) and position the LED assembly to the desired position. All the while, the system (1000) displays the intermittent resultant bearing or range, and latitude or longitude values in this screen. Once the desired position is reached, the user presses a specific key to stop further movement of the LED assembly. Thereafter, the crosshair (104), for example, turns red, indicating the crosshair (104) is no longer under trackball’s (119) control.

[0059] After fixing the position of the track, the user can enter the course, speed, SOR, classification and type of the neighbouring vessel. When the actual course and speed are not known, the user can enter the fix by giving only the position, either range, bearing or latitude, longitude combination, and later update the position of the track. The system (1000) calculates the relative velocity and hence, the resultant course and speed of the track. Once the course and speed are known, thereafter the system (1000) carries out DR on the tracks position and updates the tracks table regularly.

[0060] When the track’s position, speed and course are known, the user instructs the system (1000) to calculate the range and bearing at CPA and Time to Closest Point of Approach (TCPA) to the nearest one minute. If the CPA has already elapsed, the system (1000) indicates the TCPA in negative. Thereafter, the user has the option to ask the system (1000) to show the current vessel’s position or track’s position at the CPA. When the track’s position, speed and course are known, the user may provide the intercept speed (or Maximum current vessel speed) and ask the system (1000) to calculate the course to intercept. The system (1000) calculates the course to intercept, time to intercept and the intercept position. The user may select ‘Show X’ and take the crosshair (104) to the intercept position. Once the intercept point is noted, the user may click on ‘Show Track’ and the crosshair indicates the track’s current position.

[0061] While entering the track’s data, the user may enter the Stand Off Radius (SOR) for that track. During Dead Reckoning (DRing), if any of the tracks enter the SOR of any other tracks, the system (1000) issues alert in the alert window on the screen of the display unit (300). Also, if any of the track has entered into the SOR of current vessel, the system (1000) issues relevant warning. The track’s row whose SOR is breached is shown, for example, blinking. During the operation of the system (1000), if the user desires to delete a track, then the user selects a track by clicking on the track’s name on the table and select “Delete Track” function from Additional Special Function of the module on the screen of the display unit (300). The system (1000) prompts for confirmation and when confirmed by the user, the track is deleted from the database.

[0062] This screen also facilitates the naming of tracks which is achieved by a virtual keyboard. The keyboard (118) on the device (100) has only numeric keys. Quite often the user wants to refer a track, for example, as ‘RVJ’ or ‘RNJ’ instead of Trk1, Trk2 or the like. This is achieved by providing the virtual keyboard. For example, on the tracks screen, after the user selects a track, the user selects “Rename Track” under Additional Special Function. The virtual keyboard containing alphanumerical keys pops up. The user may enter up to 4 letters and click OK on the virtual keyboard or press Enter from the device’s keyboard (118). Therefore, the selected track is shown and referred with the new name assigned by the user.

[0063] Further, in this screen by default, the user can view the range and distance in Nm. However, the user can view them in K Yards, if the user so desires, by selecting between the Nm and K Yards buttons.

[0064] For example, the another screen, that is, the Way Point Screen permits the user or the operator to carry out the activities, such as, but not limited to:
a) Waypoint can be created by entering latitude and longitude values or coordinates;
b) Waypoint can be created by moving the lighted crosshair (104) on chart using the trackball (119);
c) User has the facility to rename and delete the valid waypoint;
d) User can enter the current vessel’s speed to calculate the time taken to complete the leg or vice versa.

[0065] The user can select a row from the waypoint table and enter the position. Alternatively, the user can use “Posn WP 1 using TrackBall” function under Additional Special Function ‘TrkFn’ (2). Once the waypoint is created, the LED assembly moves to the waypoint position, if that is within the chart area; else the system (1000) issues an alert message that the ‘Waypoint is outside the chart area’. Further, the user can enter current vessel’s speed to cross from one waypoint to another and the system (1000) gives the Estimated Time of Arrival (ETA) to complete the leg. The system (1000) also displays the distance to the next waypoint and the course to steer (CTS) from one waypoint to the other.

[0066] The user can also ‘Clear’ the waypoint which means the waypoint is not ‘included’ by selecting the value of ‘Incl’ to No for the calculations; however, the data remains on the table. Further, the user can however, totally delete a waypoint by selecting ‘Delete WP 1’ option from the Additional Special Function TrkFn (2). By using the virtual keyboard, the user can name the waypoint and use them as Lettered Positions (LPs).

[0067] For example, the another screen, that is, the Man Over Board Screen permits the user or the operator to carry out the activities, such as, but not limited to:
a) User can switch between MOB Position and current vessel’s position by clicking on ‘Show MOB posn’;
b) Find course to steer.

[0068] For example, the another screen, that is, the History/Future Screen permits the user or the operator to carry out the activities, such as, but not limited to:
a) User can store the history of current vessel as well as valid tracks by clicking ‘Store Hist’;
b) User can either select the duration or move the slider to see the history data of all tracks as well as current vessel;
c) User can either select the duration or move the slider to see the future data of all tracks as well as current vessel.

[0069] In this screen, all tracks, whose course and speed are available are shown. The current positions of all tracks are shown in a table in frozen condition. The user can observe all tracks, their range and bearing with respect to current vessel. A total of 24 hours of history or 24 hours of future positions can be seen on this page. There are buttons to move back into history or into future. This can be observed from the time indicated. If there are no data for a track in the history (for example, the track was not created then), that row will be empty. At all times the range and bearing with respect to current vessel will be shown. This assists the user to analyze an old situation or predict the future formation. In case, a track has been renamed in Tracks screen, that track will appear with that new name assigned. The selection of time can be entered using a slider also.

[0070] In accordance with an embodiment of the present invention, the device (100) for continuous plotting of relative positions of vessels at sea or sub-sea level is shown in FIG. 2(a) and (b). The device (100), as shown in FIG. 3 and FIG. 2(b), comprises of a housing (130), the X-Y gantry (110), the carriage assembly (112) and the first stepper motor (114) and a second stepper motor (116). The X-Y gantry (110) is removably coupled with the housing (130) and configured electronically with the control unit (200). Further, the X-Y gantry (110) has the nautical chart (120) which placed on a top transparent surface of the X-Y gantry (110) such as, but not limited to, flat glass or acrylic polymer transparent surface, as shown in FIG. 1 and Fig. 2(b). The carriage assembly (112) has the cross arms (102a,102b) and the crosshair (104) mounted on the cross arms (102a).The cross arms (102a,102b) are placed orthogonally with respect to each other. Moreover, the carriage assembly (112) moves on two parallel guides installed in X-direction along the length of the housing (130).The carriage assembly (112) is mounted on a chassis with a heavy base plate. The base plate has holes for mounting the X-Y gantry (110) on foundation. Further, a contraption holding the crosshair (104) moves in Y-direction (along the breadth of the housing).

[0071] In accordance with an embodiment of the present invention, the first stepper motor (114) and the second stepper motor (116) is configured to drive the cross arms (102a, 102b) of the carriage assembly (112). In particular, the first stepper motor (114) imparts one of the cross arms (102a) a linear motion in an X-axis and the second stepper motor (116) imparts other cross arm (102b) a linear motion in Y-axis. Further, the first stepper motor (114) and the second stepper motor (116) are coupled to the X and Y drives by a gear box and a coupling unit. For example, the first stepper motor (114) and the second stepper motor (116) which are high torque precision motors has 102400 steps to cover 360-degree rotation. Thus, the least count of each step works out to 0.2 for 1 step. This translates to position accuracy of 1 mm which is far better than normal CNC machines. Such positioning accuracy is essential for small scale charts where 1” could represent 0.01 nautical miles. Further, such accurate positioning is important for the functional correctness and precise position marking.

[0072] In accordance with an embodiment of the present invention, the X-Y gantry (110) is equipped with a keyboard (118) with Fixed Function Keys (FFK) and a Trackball (119) for enabling a user to key-in user defined data. The keyboard (118) further comprises of twenty one alpha numeric keys and 12 Fixed Function Keys. The user defined data fed using the keyboard (118) is monitored using the display unit (300).

[0073] In accordance with an embodiment of the present invention, the control unit (200), as shown in FIG. 4, comprises a module configured to manage operations of the X-Y gantry (110) and the control unit (200).The control unit (200) resolves motion data received from the plurality of sensors of the vessels into motion vectors by using the module of the control unit (200) which thereby converts into a signal for driving the cross arms (102a, 102b) in X-axis and Y-axis. Further, the movement of the cross arms (102a, 102b) in X-axis and Y-axis enables movement of the crosshair (104) such that the crosshair (104) which is mounted on the cross arm (102a) projects on the nautical chart (120) thereby allowing continuous plotting of relative positions of the vessels at sea or sub-sea level on the nautical chart (120).

[0074] In other words, the device (100) depicts the current position of the vessel at sea by the crosshair (104) projected from beneath the nautical paper chart (120) placed on top of the transparent surface of the X-Y gantry (110). Further, the position of the specific vessel is updated regularly based on the feed from onboard motion sensors of the vessel, namely, gyro compass for heading, Log for speed or geographical position (latitude and longitude coordinates) received from GPS.

[0075] In accordance with an embodiment of the present invention, a method for continuous plotting of relative positions of vessels at sea or sub-sea level is provided. At first step of the method, the control unit (200) and the device (100) having an X-Y gantry (110) configured with the nautical chart (120) are integrated. The control unit (200) is configured electronically with the device (100) such that the control unit (200) resolves motion data received from the onboard plurality of sensors of the vessels into the motion vectors.

[0076] In accordance with an embodiment of the present invention, at second step of the method, the display unit (300) having the interactive user interface is electronically configured with the control unit (200) and the device (100). At third step of the method, at least one mode is selected from, but not limited to, a group consisting of GPS mode, or Log or gyro mode, or DR mode, or Waypoint mode, or Track mode, or Man overboard mode, or History or Future mode, or Diagnostic mode displayed on the interactive user interface of the display unit (300).

[0077] In accordance with an embodiment of the present invention, at fourth step of the method, the motion vectors received from the control unit (200) are resolved into the signal along the lines of longitude and latitude based on the motion vectors and mode selected on the display unit (300) for driving cross arms (102a,102b) of the carriage assembly (112) of the X-Y gantry (110) in X-axis and Y-axis. Further, the movement of the crosshair (104) mounted on the cross arm (102a) is enabled due to the movement of the cross arms (102a,102b) in X-axis and Y-axis thereby allowing continuous plotting of relative positions of the vessels at sea or sub-sea level on the nautical chart (120), at fifth step of the method.

[0078] In accordance with an embodiment of the present invention, a method of chart referencing is provided whenever a new chart is placed on the X-Y gantry (110) of the device (100). At first of the method, the control unit (200) and the device (100) having the X-Y gantry (110) which is configured with the nautical chart (120) are integrated. Further, the control unit (200) is configured electronically with the device (100) and converts geographical position of a selected point on the nautical chart (120) comprising of latitude and longitude coordinates into reference position for stepper motors (114, 116) which moves the X-Y gantry (110).The control unit (200) further resolves motion data received from the onboard plurality of sensors of the vessels into the motion vectors. Furthermore, the nautical chart (120) is the paper nautical chart. The paper nautical chart includes such as, but not limited to, Mercator chart, General Operating Plot (GOP), or Line of Position (LOP).

[0079] In accordance with an embodiment of the present invention, at second step of the method, the control unit (200) is electronically configuring to automatically derive a chart scale from at least two geographical positions and confirm the chart scale by referencing with a third geographical position.

[0080] In accordance with an embodiment of the present invention, at third step of the method, the at least one mode is selected from, but not limited to, a group consisting of GPS mode, or Log or gyro mode, or DR mode, or Waypoint mode, or Track mode, or Man overboard mode, or History or Future mode, or Diagnostic mode displayed on the interactive user interface of the display unit (300). Further, the display unit (300) is electronically configured with the control unit (200) and the device (100).

[0081] In accordance with an embodiment of the present invention, at fourth step of the method, the motion vectors are resolved into the signal along the lines of latitude and longitude based on acquired motion data and mode selected over the display unit (300) for driving cross arms (102a, 102b) of the carriage assembly (112) of the X-Y gantry (110) in X-axis and Y-axis. At fifth step of the method, computation of the signal for movement of the stepper motors (114, 116) by the control unit (200) is enabled and consequently movement of the crosshair (104) mounted on the cross arm (102a) due to the movement of the cross arms (102a, 102b) in X-axis and Y-axis thereby allowing continuous plotting of relative positions of the vessels at sea or sub-sea level on the nautical chart (120) to accurately depict the current geographical position on the nautical chart (120).

[0082] In accordance with an embodiment of the present invention, a method for continuous plotting of positions of a specific vessel and relative positions of a target vessel over a plain sheet is provided. This method is referred as General Operating Plot (GOP). Further, the plain sheet may be a plain drawing sheet. The specific vessel includes the current vessel. At first step of the method, the control unit (200) and the device (100) having the X-Y gantry (110) configured with a plain sheet are integrated. Further, the control unit (200) is electronically configured for receipt of user defined geographical positions of latitude and longitude.

[0083] In accordance with an embodiment of the present invention, at second step of the method, a scale defined by the user for per unit movement corresponding to nautical miles is evaluated for driving cross arms (102a, 102b) of the X-Y gantry (110) of the device (100). At third step of the method, the at least one mode is selected from, but not limited to, a group consisting of GPS mode, or Log or gyro mode, or DR mode, or Waypoint mode, or Track mode, or Man overboard mode, or History or Future mode, or Diagnostic mode displayed on the interactive user interface of the display unit (300). Further, the display unit (300) is electronically configured with the control unit (200) and the device (100). At fifth step of the method, the motion data of the user defined geographical positions of latitude and longitude are resolved into the motion vectors which thereby convert into the signal along the lines of longitude and latitude based on the motion data and mode selected on the display unit (300) for driving the cross arms (102a,102b) of the carriage assembly (112) of the X-Y gantry (110) in X-axis and Y-axis thereby allowing continuous plotting of positions of the specific vessel and relative positions of the target vessel on the plain sheet.

[0084] In accordance with an embodiment of the present invention, the user is enabled to perform three-point referencing if the chart is of Mercator type. Using the Mercator chart, the user reference the chart at two points - preferably at extreme corners (bottom left and top right) – by entering the corresponding positional values and then by taking an LED assembly to the respective point on the chart. The LED assembly changes the colour, for example, to Green indicating that the assembly is ready to move. The user can then move the LED assembly using the trackball (119) to the required point on the chart and when positioned correctly completes with a specific button. The system acknowledges the entry by changing the colour of the LED assembly, for example, to Red and the LED assembly stops moving when the trackball (119) is moved. Similarly, the user enters the second reference point at the top right corner. The system displays ‘Reference Completed’ and calculates the chart ratio. Additionally, for example, the user can select the datum between WGS 84 (default) and Everest 69.

[0085] In accordance with an embodiment of the present invention, the user is enabled to perform single point referencing if the chart is of GOP type. The user may use GOP sheet as the same is required for most of the watercrafts such as, anti-submarine warfare. In this case, the user is expected to enter the scale (1 inch = xx NM) followed by single point referencing. Once the chart referencing is done, the user is allowed to select any of the other functionalities. During the course of operation, it is possible that the chart might have moved unintentionally due to poor handling. Hence in a prolonged duration, the user may want to confirm whether the reference points are indicated correctly. This is achieved by the buttons, for example, ‘Show Ref1’ and ‘Show Ref 2’ buttons.

[0086] While referencing, there is a possibility of skew due to non-parallel alignment of charts with respect to the sides of the X-Y gantry (110). To avoid that, the system provides the facility ‘Show Ref 3’, whereby it shows the third point of the triangle and corresponding latitude and longitude values as calculated by the system for internal calculations. The user can take the LED assembly to this third Ref point and completes the referencing as shown below.

[0087] In accordance with an embodiment of the present invention, the user is enabled to align the chart vertically. In accordance with another embodiment of the present invention, the user is enabled to align the chart horizontally. In order to assist the user to position the chart parallel to the electrical axes of the X-Y gantry (110), the system provides ‘Align Chart’ button. Upon clicking this button, the LED assembly is ready to move with the trackball (119) and the user can position the LED assembly on any of the horizontal line. The user presses a specific key and the LED changes to, for example, White colour. Now, when the user presses left or right arrow keys on the keyboard (118), the LED assembly moves in a horizontal line parallel to the X-axis of the X-Y gantry. The user may try two or three times and notice if there is any skew and avoid the skew by correctly adjusting the chart. Similarly, the user can use ‘Up’ and ‘Down’ arrow keys to move the LED assembly to go parallel to the Y-axis and totally eliminate the skew. Further, the user presses ‘Finish’ to come out of ‘Align Chart’ facility provided on the screen of the display unit (300). Thereafter, the LED changes to, for example, Red colour to indicate that the Align Chart functionality is over.

[0088] In accordance with an embodiment of the present invention, a method of detection of skew in a nautical chart (120) placement on the transparent top of the X-Y gantry (110) is provided. The nautical chart (120) is the paper nautical chart. At first step of the method, the control unit (200) is configured to operate a module to check orthogonality of latitude and longitude axes of the nautical chart (120) and parallelism of the latitude and longitude axes with the orthogonal X-axis and Y-axis of the device (100) having the X-Y gantry (110). At second step of the method, the module is enabled to measure an angle of skew based on the difference in the orthogonality of latitude and longitude axes of the nautical chart (120) and difference between the parallelism of the latitude and longitude axes with the orthogonal X-axis and Y-axis of the device (100).

[0089] In accordance with an embodiment of the present invention, at third step of the method, the data of the angle of skew is resolved into the motion vectors for a specific vessel movement to compute the compensation to be provided based on the resolved motion vectors to drive the cross arms (102a, 102b) and the crosshair (104) for continuous plotting of accurate geographical position of the specific vessel. In particular, the compensation to be provided based on the resolved motion vectors is computed to drive the stepper motors (114, 116) which in turn drives the cross arms (102a, 102b) and the crosshair (104). Further, the specific vessel includes the current vessel or current ship on which the system (1000) is installed.

[0090] In accordance with an embodiment of the present invention, a method of activating anti-collision alarm based on relative positions of vessels at sea or sub-sea level is provided, in case the current vessel and target vessel’s motion vectors converge. At first step of the method, the control unit (200) is configured to receive current geographical position of the specific vessel by selecting at least one mode from, but not limited to, a group consisting of GPS mode, or Log or gyro mode, or DR mode, or Waypoint mode, or Track mode, or Man overboard mode, or History or Future mode, or Diagnostic mode displayed on the interactive user interface of the display unit (300). Further, the display unit (300) is electronically configured with the control unit (200) and the device (100) having the X-Y gantry (110) configured with the nautical chart (120).

[0091] In accordance with an embodiment of the present invention, the motion data of the target vessel and the specific vessel from onboard plurality of sensors of the vessels is received such as the target coordinates (latitude and longitude) or range and bearing from the specific vessel, at second step of the method. In other words, the motion data of the target vessel comprises latitude and longitude coordinates, and motion data of the specific vessel comprises range and bearing of the specific vessel. At third step of the method, the motion data of the target vessel and the specific vessel is resolved into the motion vectors by the control unit (200) to compute relative motion such as, speed and course of the target vessel with reference to the specific vessel. Further, the specific vessel includes the current vessel on which the system (1000) is installed.

[0092] In accordance with an embodiment of the present invention, at fourth step of the method, the control unit (200) is configured to compute Closest Point of Approach (CPA) at which the specific vessel and the target vessel converges with each other, and to compute Time to Closest Point of Approach (TCPA) for the specific vessel and the target vessel to be at a closest point with respect to each other. Further, the control unit (200) is configured to pre-empt a possibility of collision when CPA approaches to zero thereby activating the audio-visual alarm which draws attention of the operator to avoid a collision at sea or sub-sea level, at fifth step of the method.

[0093] In accordance with an embodiment of the present invention, a method of determining a target true motion or “Target Motion Analysis (TMA)” of the target vessel in the absence of range information from the current vessel at sea or sub-sea level is provided. At first step of the method, the control unit (200) is configured to continuously receive only bearing information of the target vessel with reference to the specific vessel. At second step of the method, the control unit (200) is enabled to accept an estimate of range information of the target vessel from the operator or passive sensors. Further, the control unit is allowed to operate the module for iterative regression features to estimate target true motion with respect to course, speed and range of the target vessel and refine the estimate of range information of the target vessel by repetitive operation of the module, at third step of the method.

[0094] In accordance with an embodiment of the present invention, at fourth step of the method, bearing information derived of the target vessel and bearing information actually obtained from the passive sensors is compared to generate final target true motion in absence of the range information from the specific vessel.

[0095] In accordance with an embodiment of the present invention, a method of classifying target vessels is provided. The method comprises user selectable intensity of the crosshair (104) and colour of the crosshair (104) light automatically based on the classification of the target vessel. At first step of the method, the control unit (200) is configured to automatically receive a target classification input from a predetermined database provided by the operator. At second of the method, an electronic card is enabled to automatically control colour of the light of the illuminated crosshair (104) based on the target classification input. The control unit (200) is configured to automatically receive intensity setting input for the illuminated crosshair (104) from a predetermined database provided by the operator based on the target classification input, at third step of the method. Accordingly, the target vessels are classified based on the intensity and colour of light of the illuminated crosshair (104).

[0096] In accordance with an embodiment of the present invention, the system (1000) makes possible to shift the crosshair (104) from the current vessel to indicate selected track position. Further, provision has been made in the system (1000) to have multi-coloured light projection to facilitate visual identification of the current vessel or the neighbouring vessels. There are many different colours possible which indicate the classification of vessels. The colour classification may include, but not limited to, as under:
Yellow: To indicate current vessel
Green: To indicate Friendly neighbouring vessel
Red: To indicate Hostile neighbouring vessel
White: To indicate Neutral neighbouring vessel
Magenta: To indicate Unknown neighbouring vessel

[0097] In accordance with an embodiment of the present invention, the target classification input for example, friend, foe or neutral is automatically received by the control unit (200) and based on the target classification received, the colour of the light of the crosshair (104), for example, green, red or white is automatically controlled by the electronic card. Further, the electronic card is configured to compute the current required to drive the LED based crosshair (104) brilliance on the basis of the setting made by the operator.

[0098] In accordance with an embodiment of the present invention, a method of determining the man overboard (MOB) position and course to reach the position is provided. This method allows marking of the geographical position on the paper nautical chart (120) in case of a “Man falling Over Board (MOB)” and guide the current vessel to move in a predefined route so as to pick up or rescue that man quickly. At first step of the method, the control unit (200) is configured to receive a man overboard input from the operator and to mark the geographical position on the nautical chart (120). Further, the nautical chart (120) is the paper nautical chart.

[0099] In accordance with an embodiment of the present invention, at second step of the method, a course to steer to reach the geographical position of the man overboard is automatically computed by the control unit (200). Further, at the third step of the method, the interactive user interface of the display unit (300) is configured to continuously depict the course to steer as guidance to the operator for immediate rescue of the man overboard. The display unit (300) is electronically configured with the control unit (200) and the device (100) having the X-Y gantry (110) which is configured with the nautical chart (120).

[00100] In accordance with an embodiment of the present invention, when MOB button is pressed or selected on the screen of the display unit (300), the module marks the MOB position and thereafter, continuously gives the range and bearing to the MOB position. Further, the module assists the operator to come back to the MOB position. In particular, when the MOB option is shown on the screen, the user presses or clicks on the ‘MOB’ tab and the system (1000) takes the user to the MOB screen page. In this screen the user may carry out activities, for example:
a) The user can switch between MOB position and current vessel’s position by clicking on ‘Show MOB position’; and
b) Find course to steer.

[00101] Further, the system (1000) stores the current position of the current vessel as MOB position and the current time as MOB time. The LED assembly is brought to the center irrespective of the chart selected. By default, a scale of, for example, 1 inch = 0.5 Nm is chosen. Then onwards the current vessel is continuously shown by the LED assembly. The system (1000) continuously shows the range to MOB position and the course to steer to reach the MOB position. Further, these tracks and history are updated on the background. At any time, if the user presses ‘Show MOB Position’, the LED assembly is taken to MOB position and the button text changes to ‘Show current vessel Position’ and clicking now makes the LED to go on the current position of the current vessel. When the user clicks on any other tab, the last set chart scale is automatically applied and the LED assembly goes to current vessel’s position.

[00102] In accordance with an embodiment of the present invention, the hardware of the system (1000) is configured to meet the certification and qualification standards of JSS 55555 guidelines. The design of the hardware ensures no electromagnetic interference to other equipment on board the platform; ensures no electromagnetic susceptibility of other equipment on board the platform; and ensures the capability to withstand shock and vibration as expected to be experience by the platform when moving at sea wherein special shock mounts based on computed shock expectation is selected, wherein appropriate electronic measures are implemented to shield the equipment to and from electromagnetic radiation to/from other equipment onboard and wherein the entire system is subjected to various kinds of measurement test in government laboratories to confirm compliance to the standard.

[00103] In accordance with an embodiment of the present invention, the hardware of the module of the system (1000) is configured to meet the certification and qualification standards of IEE 12207 guidelines.

[00104] In accordance with an embodiment of the present invention, the system (1000) may be potentially used in watercrafts such as, but not limited to, ships, submarines, or naval warships.

[00105] Apart from what is disclosed above, the present invention also includes some additional benefits and advantages. Few of the additional benefits are mentioned below:

• The present invention provides a system for navigation that can be used for general and strategic purposes.

• The present invention provides the system which operates in harsh conditions and capable of bearing shock and vibration during the operation.

• The present invention provides a device that is easy to configure with any existing source of navigation of vessel.

• The system involves a device for accurate and continuous plotting of relative positions of vessels at sea or sub-sea level during day and night.

• The system provides continuous and real-time plotting of a current position of a vessel in which the device is installed.

• The system provides the feature of anti-collision alarm and also raises the error alarms upon sensor data error, communication error, or drive motor error.

• The system also facilitates visual identification of own vessel or neighbouring vessels in proximity.

The foregoing descriptions of exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiment was chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions, substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but is intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.
,CLAIMS:We Claim:

1. A system (1000) for continuous plotting of relative positions of vessels at sea or sub-sea level, the system (1000) comprising:
a device (100) having an X-Y gantry (110) configured with a nautical chart (120), said X-Y gantry (110) having
a carriage assembly (112) configured to have cross arms (102a, 102b) and a crosshair (104) mounted on said cross arm (102a),
a first stepper motor (114) and a second stepper motor (116) configured to drive said cross arms (102a, 102b) of said carriage assembly (112);
a control unit (200) operationally coupled with said device (100);
a display unit (300) having an interactive user interface and configured electronically with said control unit (200) and said device (100),
wherein said first stepper motor (114) imparts one of said cross arms (102a) a linear motion in an X-axis and said second stepper motor (116) imparts other cross arm (102b) a linear motion in Y-axis;
wherein said control unit (200) resolves motion data received from a plurality of sensors of said vessels into motion vectors which thereby being converted into a signal for driving said cross arms (102a, 102b) in X-axis and Y-axis;
wherein said movement of said cross arms (102a, 102b) in X-axis and Y-axis enables movement of said crosshair (104) mounted on said cross arm (102a) thereby allowing continuous plotting of relative positions of said vessels at sea or sub-sea level on said nautical chart (120).

2. The system (1000) as claimed in claim 1, wherein said crosshair (104) is multi-coloured and configured for visual identification of a specific vessel and other vessels in proximity.

3. The system (1000) as claimed in claim 1, wherein said X-Y gantry (110) further comprises a keyboard (118) with Fixed Function Keys (FFK) configured for user interaction.

4. The system (1000) as claimed in claim 1, wherein said plurality of sensors are navigational sensors selected from a group consisting of motion sensors, rotation sensors, magnetic sensors, and tactical sensors.

5. The system (1000) as claimed in claim 5, wherein said motion sensors are selected from a group consisting of Gyro Compass, Log, Data Distribution Unit, and GPS; and said tactical sensors are selected from a group consisting of Radar, Sonar, and Periscope.

6. The system (1000) as claimed in claim 1, wherein said control unit (200) comprises a processor, a power supply unit, and a module.

7. The system (1000) as claimed in claim 6, wherein said module of said control unit (200) is configured to manage operations of said X-Y gantry (110) of said device (100).

8. The system (1000) as claimed in claim 7, wherein said module is configured to receive motion sensor data from Gyro Compass, Log, Data Distribution Unit, and GPS in serial format.

9. The system (1000) as claimed in claim 7, wherein said module is configured to receive motion sensor data in serial Ethernet, MIL 1553 and Data Bus format.

10. The system (1000) as claimed in claim 7, wherein said module is configured to receive tactical sensor data from Radar, Sonar and Periscope.

11. The system (1000) as claimed in claim 7, wherein said module is configured to automatically correct skew in placement of said nautical chart (120).

12. The system (1000) as claimed in claim 7, wherein said module is configured to automatically derive scale of said nautical chart (120) based on two point referencing or three point referencing technique.

13. The system (1000) as claimed in claim 7, wherein said module is configured to operate when course and speed of said vessels are fed manually by a user.

14. The system (1000) as claimed in claim 7, wherein said module is configured for route planning and creation of waypoints.

15. The system (1000) as claimed in claim 7, wherein said module is configured for track replay and predict future position of a specific vessel and other vessels in proximity based on current course and speed of said specific vessel.

16. The system (1000) as claimed in claim 7, wherein said module is configured to raise error alarms upon sensor data error, communication error, drive motor error, or combinations thereof.

17. The system (1000) as claimed in claim 7, wherein said module is configured to record a position of man overboard (MOB) and continuously display a course to steer to reach said position of said man overboard (MOB).

18. The system (1000) as claimed in claim 7, wherein said module is configured to compute relative velocity and depict Closet Point of Approach (CPA) and Time to reach Closet Point of Approach (TCPA).

19. The system (1000) as claimed in claim 7, wherein said module is configured to compute Target Motion Analysis (TMA) using Doppler-Bearing tracking method for observing dominant tonal frequency and its variation which is proportional to closing or opening speed.

20. The system (1000) as claimed in claim 7, wherein said module is configured to compute Target Motion Analysis (TMA) using Range and Bearing received from sonar.

21. The system (1000) as claimed in claim 7, wherein said module is configured to compute General Operating Plot (GOP).

22. The system (1000) as claimed in claim 1, wherein said interactive user interface has a plurality of user access options which are configured to provide an access to graphical content relating to a plurality of functions.

23. A device (100) for continuous plotting of relative positions of vessels at sea or sub-sea level, the device (100) comprising:
a housing (130); and
an X-Y gantry (110) removably coupled with said housing (130) and configured electronically with a control unit (200), said X-Y gantry (110) having
a nautical chart (120) placed on a top transparent surface of said X-Y gantry (110),
a carriage assembly (112) configured to have cross arms (102a, 102b)and a crosshair (104) mounted on said cross arm (102a), and
a first stepper motor (114) and a second stepper motor (116) configured to drive said cross arms (102a, 102b) of said carriage assembly (112);
wherein said first stepper motor (114) imparts one of said cross arms (102a) a linear motion in an X-axis and said second stepper motor (116) imparts other cross arm (102b) a linear motion in Y-axis;
wherein said control unit (200) resolves motion data received from a plurality of sensors of said vessels into motion vectors which thereby being converted into a signal for driving said cross arms (102a, 102b) in X-axis and Y-axis;
wherein said movement of said cross arms (102a, 102b) in X-axis and Y-axis enables movement of said crosshair (104) such that said crosshair (104) mounted on said cross arm(102a) projects on said nautical chart (120) thereby allowing continuous plotting of relative positions of said vessels at sea or sub-sea level on said nautical chart (120).

24. The device (100) as claimed in claim 23, wherein said cross arms (102a, 102b) are placed orthogonally with respect to each other.

25. The device (100) as claimed in claim 23, wherein said X-Y gantry (110) is equipped with a keyboard (118) with Fixed Function Keys (FFK).

26. The device (100) as claimed in claim 23, wherein said control unit (200) comprises a module configured to manage operations of said X-Y gantry (110) and said control unit (200).

27. The device (100) as claimed in claim 23, wherein said carriage assembly (112) moves on two parallel guides installed in X-direction along the length of said housing (130).

28. A method for continuous plotting of relative positions of vessels at sea or sub-sea level, the method comprising the steps of:
integrating a control unit (200) and a device (100) having an X-Y gantry (110) configured with a nautical chart (120), said control unit (200) being configured electronically with said device (100) such that said control unit (200) resolves motion data received from onboard plurality of sensors of said vessels into motion vectors;
electronically configuring a display unit (300) having an interactive user interface with said control unit (200) and said device (100);
selecting at least one mode from a group consisting of GPS mode, or Log or gyro mode, or DR mode, or Waypoint mode, or Track mode, or Man overboard mode, or History or Future mode, or Diagnostic mode displayed on said interactive user interface of said display unit (300);
resolving said motion vectors received from said control unit (200) into a signal along the lines of longitude and latitude based on said motion vectors and mode selected on said display unit (300) for driving cross arms (102a, 102b) of a carriage assembly (112) of said X-Y gantry (110) in X-axis and Y-axis; and
enabling movement of a crosshair (104) mounted on said cross arm (102a) due to said movement of said cross arms (102a, 102b) in X-axis and Y-axis thereby allowing continuous plotting of relative positions of said vessels at sea or sub-sea level on said nautical chart (120).

29. A method of chart referencing, the method comprising the steps of:
integrating a control unit (200) and a device (100) having an X-Y gantry (110) configured with a nautical chart (120), said control unit (200) configured electronically with said device (100) and converts geographical position of a selected point on said nautical chart (120) comprising of latitude and longitude into reference position for stepper motors (114, 116) which moves said X-Y gantry (110), said control unit (200) further resolves motion data received from onboard plurality of sensors of said vessels into motion vectors;
electronically configuring said control unit (200) to automatically derive a chart scale from at least two geographical positions and confirm said chart scale by referencing with a third geographical position;
selecting at least one mode from a group consisting of GPS mode, or Log or gyro mode, or DR mode, or Waypoint mode, or Track mode, or Man overboard mode, or History or Future mode, or Diagnostic mode displayed on an interactive user interface of a display unit (300), said display unit (300) being electronically configured with said control unit (200) and said device (100);
resolving said motion vectors into a signal along the lines of latitude and longitude based on acquired motion data and mode selected over said display unit (300) for driving cross arms (102a, 102b) of a carriage assembly (112) of said X-Y gantry (110) in X-axis and Y-axis; and
enabling computation of said signal for movement of said stepper motors (114, 116) by said control unit (200) and consequently movement of a crosshair (104) mounted on said cross arm (102a) due to movement of said cross arms (102a, 102b) in X-axis and Y-axis thereby allowing continuous plotting of relative positions of said vessels at sea or sub-sea level on said nautical chart (120) to accurately depict the current geographical position on said nautical chart (120).

30. A method for continuous plotting of positions of a specific vessel and relative positions of a target vessel over a plain sheet, the method comprising steps of:
integrating a control unit (200) and a device (100) having an X-Y gantry (110) configured with a plain sheet and electronically configuring said control unit (200) for receipt of user defined geographical positions of latitude and longitude;
evaluating a scale defined by said user for per unit movement corresponding to nautical miles for driving cross arms (102a, 102b) of said X-Y gantry (110) of said device (100);
selecting at least one mode from a group consisting of GPS mode, or Log or gyro mode, or DR mode, or Waypoint mode, or Track mode, or Man overboard mode, or History or Future mode, or Diagnostic mode displayed on an interactive user interface of a display unit (300), said display unit (300) being electronically configured with said control unit (200) and said device (100); and
resolving motion data of said user defined geographical positions of latitude and longitude into said motion vectors which thereby being converted into a signal along the lines of longitude and latitude based on said motion data and mode selected on said display unit (300) for driving said cross arms (102a, 102b) of a carriage assembly (112) of said X-Y gantry (112) in X-axis and Y-axis thereby allowing continuous plotting of positions of said specific vessel and relative positions of said target vessel on said plain sheet.
31. A method of detection of skew in a nautical chart (120), the method comprising the steps of:
configuring a control unit (200) to operate a module of said control unit (200) to check orthogonality of latitude and longitude axes of said nautical chart (120) and parallelism of said latitude and longitude axes with an orthogonal X-axis and Y-axis of a device (100) having an X-Y gantry (110);
enabling said module to measure an angle of skew based on the difference in the orthogonality of latitude and longitude axes of said nautical chart (120) and difference between the parallelism of said latitude and longitude axes with said orthogonal X-axis and Y-axis of said device (100); and
resolving data of said angle of skew into motion vectors for a specific vessel movement to compute the compensation to be provided based on said resolved motion vectors to drive cross arms (102a, 102b) and a crosshair (104) for continuous plotting of accurate geographical position of said specific vessel.

32. A method of activating anti-collision alarm based on relative positions of vessels at sea or sub-sea level, the method comprising the steps of:
configuring a control unit (200) to receive current geographical position of a specific vessel by selecting at least one mode from a group consisting of GPS mode, or Log or gyro mode, or DR mode, or Waypoint mode, or Track mode, or Man overboard mode, or History or Future mode, or Diagnostic mode displayed on an interactive user interface of a display unit (300), said display unit (300) being electronically configured with said control unit (200) and a device (100) having an X-Y gantry (110) configured with a nautical chart (120);
receiving motion data of a target vessel and a specific vessel from onboard plurality of sensors of said vessels;
resolving said motion data of said target vessel and said specific vessel into motion vectors by said control unit (200) to compute relative motion of said target vessel with reference to said specific vessel;
configuring said control unit (200) to compute Closest Point of Approach (CPA) at which said specific vessel and said target vessel converges with each other, and to compute Time to Closest Point of Approach (TCPA) for said specific vessel and said target vessel to be at a closest point with respect to each other; and
configuring said control unit (200) to pre-empt a possibility of collision when CPA approaches to zero thereby activating said audio-visual alarm to avoid a collision at sea or sub-sea level.

33. The method as claimed in claim 32, wherein said specific vessel is current vessel on which a system (1000) is installed.

34. The method as claimed in claim 32, wherein said motion data of said target vessel comprises latitude and longitude coordinates, and motion data of said specific vessel comprises range and bearing of said specific vessel.

35. A method of determining a target true motion of a target vessel at sea or sub-sea level, the method comprising the steps of:
configuring a control unit (200) to continuously receive only bearing information of said target vessel with reference to a specific vessel;
enabling said control unit (200) to accept an estimate of range information of said target vessel from an operator or passive sensors;
allowing said control unit (200) to operate a module to estimate target true motion with respect to course, speed and range of said target vessel and refining said estimate of range information of said target vessel by repetitive operation of said module; and
comparing said bearing information derived of said target vessel and bearing information actually obtained from said passive sensors to generate final target true motion in absence of a range information from a specific vessel.

36. A method of classifying target vessels, the method comprising the steps of:
configuring a control unit (200) to automatically receive a target classification input from a predetermined database provided by an operator;
enabling an electronic card to automatically control colour of light of an illuminated crosshair (104) based on said target classification input;
configuring said control unit (200) to automatically receive intensity setting input for said illuminated crosshair (104) from a predetermined database provided by said operator based on said target classification input; and
classifying said target vessels based on intensity and colour of light of said illuminated crosshair (104).

37. A method of determining a man overboard (MOB) position and course to reach said position, the method comprising the steps of:
configuring a control unit (200) to receive a man overboard input from an operator and mark a geographical position on a nautical chart (120);
automatically computing a course to steer to reach said geographical position of said man overboard by said control unit (200); and
configuring an interactive user interface of a display unit (300) to continuously depict said course to steer as guidance to said operator for immediate rescue of said man overboard, said display unit (300) being electronically configured with said control unit (200) and a device (100) having an X-Y gantry (110) configured with said nautical chart (120).