Description:TECHNICAL FIELD
[0001] The present disclosure relates, in general, to the sub-surface warfare (SSW) mission, and more specifically, relates to an optimal and efficient aerial unit dipping sonar search pattern method for the sub-surface warfare (SSW) mission.

BACKGROUND
[0002] Sub-surface warfare comprises the detection, tracking, destruction, neutralization, and damage of enemy submarines. This can be accomplished in various ways by ships operating on the surface, aeroplanes/aerial units attached with dipping sonars, sensors, and friendly submarines. It is considered an important part of the larger discipline of underwater warfare and military operation.
[0003] A few examples known in the art describe the effective ways to operate an aerial unit, equipped with dipping sonar -a dipper- in SSW missions. It describes the optimal dipping pattern and the factors which will affect the dipping pattern. The existing known art aims at the calculation of optimal dipping patterns for the detection of the submarine in the SSW mission. But the difference exists in the way the parameters of the next dip are calculated depending on the previous dip parameters.
[0004] However, the existing system suffers from limitations that include as follows:
• There are more chances of submarine miss
• Search starts at zero courses so there are chances that a greater number of dips can be there and less probability of detection of a submarine
• Datum is not considered for the first dip calculation.
[0005] Therefore, it is desired to overcome the drawbacks, shortcomings, and limitations associated with existing solutions, and develop an effective search pattern which significantly reduces the chances of the submarine miss. The method significantly increases the overall probability of detection of the submarine. The calculated probability of detection may help the user to decide whether the search operation is to be carried on or not. There is a need for a method that calculates the search patterns till the endurance of the aerial unit so that the unusual calculations can be reduced. There is a need for a method that considers the last seen position of the submarine (datum) and the method starts processing calculations on the basis of the datum position. Altogether there is a need for a method of an effective search pattern, which will detect the submarine in one of its dips during the limited mission time of the aerial unit.

OBJECTS OF THE PRESENT DISCLOSURE
[0006] An object of the present disclosure relates, to the sub-surface warfare (SSW) mission, and more specifically, relates to an optimal and efficient aerial unit dipping sonar search pattern method for sub-surface warfare (SSW) mission.
[0007] Another object of the present disclosure is to provide a system and method that provides an efficient search pattern which reduces the chances of enemy submarines missing in the entire search pattern. It is achieved by taking into assumption the course of the submarine towards the platform for the first dip calculation.
[0008] Another object of the present disclosure is to provide a system and method that provides an efficient search pattern which increases the overall probability of detection of the submarine, which effectively calculates the next dip coverage angle.
[0009] Yet another object of the present disclosure is to provide a system and method that calculates the first search dip considering datum gap time, where the datum gap time is the interval of time between the detection of the submarine and the start of the search operation aerial unit take-off time.

SUMMARY
[0010] The present disclosure relates to the subsurface warfare (SSW) mission, and more specifically, relates to an optimal and efficient aerial unit dipping sonar search pattern method for subsurface warfare (SSW) missions. The main objective of the present disclosure is to overcome the drawback, limitations, and shortcomings of the existing system and solution, by providing a method for efficiently finding the search pattern for effective sub-surface warfare (SSW). The effective ways with the least chance of submarine miss by operating an aerial unit which is equipped with dipping sonar are to be provided to locate enemy submarines. In the SSW domain, a datum is the last known position of a submarine after contact has been lost. The platform is either a ground base or a surface ship from where the aerial unit takes off to start the search operation.
[0011] The present disclosure relates to a system for dipping sonar search patterns, the system includes the aerial unit equipped with dipping sonar defined as a dipper in sub-surface warfare (SSW) mission to detect, track, acquire and attack a target submarine. The aerial unit transfers a set of data to a submarine search system. The set of data pertaining to datum last position, time of detection of datum, aerial unit speed, and speed of submarine. The submarine search system includes a computation node configured to collect a set of attributes required for the calculation of the dipping position to determine a first dipping pattern. The set of attributes pertains to the area of uncertainty (AoU), speed of aerial unit, speed of submarine, dipping time and sonar detection range. The computation node can receive the set of data from the submarine search system and calculate the coverage angle of the next dipping pattern considering the attributes of the first dipping pattern. The computation node utilizes the datum detection gap time for the first dipping pattern assuming the submarine movement direction towards the platform and takes the coverage angle by lines drawn from the datum position to the intersection points of the dipping sonar detection circle and submarine probability area (SPA).
[0012] Further, the computation node can determine a sequence of dipping positions. The graphical user interface (GUI) is deployed on a screen to display the sequence of dipping positions computed by the computation node, wherein the sequence of dipping positions calculated by the submarine search system is sent to the aerial unit to search the submarine. Therefore, the system and method provide an efficient search pattern which reduces the chances of enemy submarines missing in the entire search pattern. It is achieved by taking into assumption the course of the submarine towards the platform for the first dip calculation and provides an efficient search pattern which increases the overall probability of detection of the submarine, which effectively calculates the next dip coverage angle. Further, the system calculates the first search dip considering the datum gap time, where the datum gap time is the interval of time between the detection of the submarine and the start of the search operation aerial unit take-off time.
[0013] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The following drawings form part of the present specification and are included to further illustrate aspects of the present disclosure. The disclosure may be better understood by reference to the drawings in combination with the detailed description of the specific embodiments presented herein.
[0015] FIG. 1 illustrates an exemplary block diagram of the dipping sonar search pattern system, in accordance with an embodiment of the present disclosure.
[0016] FIG. 2 illustrates an exemplary deployment diagram of the search pattern method in the submarine search system, in accordance with an embodiment of the present disclosure.
[0017] FIG. 3 illustrates an exemplary flow diagram of the SSW computation node, in accordance with an embodiment of the present disclosure.
[0018] FIG. 4 illustrates an exemplary view of the coverage angle calculation tangential from the centre of the circumference of datum, in accordance with an embodiment of the present disclosure.
[0019] FIG. 5 illustrates an exemplary view of the coverage angle calculation as per intersection points of circumference of datum and detection, in accordance with an embodiment of the present disclosure.
[0020] FIG. 6 illustrates an exemplary view of the two different approaches to search the first dip, in accordance with an embodiment of the present disclosure.
[0021] FIG. 7 illustrates an exemplary view of the two different practical approaches to search the first dip, in accordance with an embodiment of the present disclosure.
[0022] FIG. 8 illustrates an exemplary view of the series of consecutive dipping points for the dipper, in accordance with an embodiment of the present disclosure.
[0023] FIG. 9 illustrates an exemplary graphical view of the effect of sonar detection range on probability of detection, in accordance with an embodiment of the present disclosure.
[0024] FIG. 10 illustrates an exemplary graphical view of the effect of aerial unit speed on probability of detection, in accordance with an embodiment of the present disclosure.
[0025] FIG. 11 illustrates an exemplary graphical view of the effect of average submarine speed on probability of detection, in accordance with an embodiment of the present disclosure.
[0026] FIG. 12 illustrates an exemplary flow chart of method for dipping sonar search pattern, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0027] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[0028] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0029] The present disclosure relates, in general, to sub-surface warfare (SSW) mission, and more specifically, relates to an optimal and efficient aerial unit dipping sonar search pattern method for sub surface warfare (SSW) mission.
[0030] The proposed system disclosed in the present disclosure overcomes the drawbacks, shortcomings, and limitations associated with the conventional system by providing an optimal and efficient search pattern for sub-surface warfare. The present disclosure generally relates to the designing of an efficient dipping sonar search pattern method which efficiently detects the submarine in one of its dips during the limited mission time of the aerial unit using the dipping sonar – a dipper – in SSW missions. It particularly relates to the development of a method to find the series of consecutive dipping points for the dipper and the next dip is calculated as per the parameters of the previous dip. It particularly relates to the development of an optimal and efficient method so that for a given number of dipping points, it maximizes the probability of detection of submarine or minimizes the expected time of detection. It describes the modifications done in the prior art and how it surpasses the conventional method of dipping sonar search patterns in certain ways. The present disclosure can be described in enabling detail in the following examples, which may represent more than one embodiment of the present disclosure.
[0031] The advantages achieved by system 100 of the present disclosure can be clear from the embodiments provided herein. The system can optimize the operation of the aerial unit, and develop an effective way to deploy the dipping sonar. The system can develop an effective dipping pattern to maximize the probability of detection of the submarine in the SSW mission. Further, the system develops the effective coverage angle of the next dipping pattern of sonar to maximize the coverage of submarines. The description of terms and features related to the present disclosure shall be clear from the embodiments that are illustrated and described; however, the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents of the embodiments are possible within the scope of the present disclosure. Additionally, the invention can include other embodiments that are within the scope of the claims but are not described in detail with respect to the following description.
[0032] FIG. 1 illustrates an exemplary block diagram of the dipping sonar search pattern system, in accordance with an embodiment of the present disclosure.
[0033] Referring to FIG. 1, the optimal and efficient aerial unit dipping sonar search pattern method for sub surface warfare (SSW) mission is disclosed. The system 100 can include discovery of enemy submarine detection devices 102, dipper in SSW mission 104, SSW computation mode 106 and graphical user interface (GUI) 108. The present disclosure provides a method for efficiently finding the search pattern for effective SSW.
[0034] The discovery of enemy submarine detection devices 102 such as fixed-wing aircraft or towed arrays from surface ships, radars, and the like is disclosed. The point of detection of the possible submarine target which is known as the datum of the suspected target and the time of detection is recorded. However, the course is unpredictable as the enemy submarine submerges into underwater subsequently. The data is fed to the dipping sonar from the external source. Following the datum given by the external source indicating the presence of a possible submarine target, an aerial unit which is equipped with dipping sonar which is referred red as a dipper in SSW mission 104 is sent to detect, track, acquire and attack the submarine (also referred to as target submarine). The dipping sonar has a sonar detection range which is used to search a submarine within a defined detection range. The dipping sonar is active sonar, which generates sound signals once lowered into position. The signal processing algorithms process the echoes that return to the sonar to locate enemy submarines.
[0035] The SSW computation mode 106 uses the optimal method to find a sequence of dipping patterns. The dipping pattern is a series of consecutive dipping points for the dipper. A dipping pattern is optimal and efficient if for a given number of dipping points, it maximizes the probability of detection of the submarine or for an infinite number of available dipping points it minimizes the expected time of detection. The GUI 108 framework is deployed on a screen which may display the dipping pattern computed by SSW computation mode 106.
[0036] The sub-surface warfare comprises the detection, tracking, destruction, neutralization, and damage of enemy submarines. This can be accomplished in various ways by ships operating on the surface, airplanes/aerial units attached with dipping sonars, sensors, and friendly submarines. It is considered an important part of the larger discipline of underwater warfare and military operation.
[0037] Hostile submarines are considered a major threat to friendly naval ships and therefore submarines become a serious military targets during naval operations. Submarines can perform a wide range of missions, including attacking other submarines, attacking surface vessels, etc. SSW is a key to obtaining sea control. The sub-surface search is an important military combat mission for submarines.
[0038] Since submarines are hard to detect, finding ways to optimize the search for and attack enemy submarines is very important. This can be achieved by sending out the aerial unit which is equipped with dipping sonar. The dipping sonar is lowered into the position which generates the sound signals and allows the aerial unit crew to listen for underwater signals. Some surveillance sources such as fixed-wing aircraft or towed arrays from surface ships provide the location which is known as the datum of the suspected target and the time of detection. After the datum is known the optimal dipping pattern for the aerial unit which is sent for the SSW mission is calculated. A dipping pattern is a series of consecutive dips for the dipper. The dipping sonar is recovered after the search is complete.
[0039] The dipping pattern is effective in way that the next dip is calculated to maximize the probability of detection of the submarine in the next dip.
[0040] The factors which affect the probability are as follows:
• Distance from aerial unit takes off to the datum
• Aerial unit velocity
• Aerial unit endurance
• Submarine velocity
[0041] Thus, the present invention overcomes the drawbacks, shortcomings, and limitations associated with existing solutions, and provides a system that can optimize the operation of the aerial unit, and develop an effective way to deploy the dipping sonar. The system can develop an effective dipping pattern to maximize the probability of detection of the submarine in SSW missions. Further, the system develops the effective coverage angle of the next dipping pattern of sonar to maximize the coverage of submarines.
[0042] FIG. 2 illustrates an exemplary deployment diagram of the search pattern method in the submarine search system, in accordance with an embodiment of the present disclosure.
[0043] FIG. 2 depicts aerial unit 202 which is used to carry the dipping sonar 204 for the purpose of submarine search after datum detection. The dipping sonar 204 is a type of active sonar which can be carried on a movable platform like aerial unit 202. A platform 206 is like marine vessel or a ground station which carries aerial unit 202 e.g., a ship which carries a helicopter. A hardware node 216 (also referred to as computation node 216, herein) hosts the submarine search application. A hardware node 218 (also referred to as user interface node 218, herein) hosts the user interface for the execution of the submarine search. A database 210 is a hardware node which contains persistent information of the submarine search system 208 and is non-volatile in nature. The submarine search system 208 consists of multiple hardware nodes 210 like computation node 216, user interface node 218 and database 210 and runs the software application like submarine search method application and the user interface for invocation of the submarine search.
[0044] The data 212 is fed to the submarine search system 208 e.g., the datum last position and the time of detection of the datum, aerial unit speed, and speed of the submarine. The dipping position 214 is calculated by the submarine search system 208 and is sent to the aerial unit 202 which follows the dipping position to search the submarine.
[0045] In an embodiment, the system 100 for dipping sonar search pattern includes the aerial unit 202 which is equipped with dipping sonar 204 defined as a dipper in sub-surface warfare (SSW) mission to detect, track, acquire and attack a target submarine. The aerial unit 202 transfers a set of data to the submarine search system 208. The set of data pertains to the datum last position, time of detection of the datum, aerial unit speed, and speed of the submarine.
[0046] The submarine search system 202 includes computation node 216 configured to determine a sequence of dipping positions. The computation node 216 collects a set of attributes required for the calculation of the dipping position to determine a first dipping pattern. The set of attributes pertains to the area of uncertainty (AoU), speed of aerial unit, speed of submarine, dipping time and sonar detection range. The computation node 216 is configured to receive the set of data from the submarine search system 208
[0047] The computation node 216 utilizes the datum detection gap time for the first dipping pattern assuming the submarine movement direction towards the platform and takes the coverage angle by lines drawn from the datum position to the intersection points of the dipping sonar detection circle and submarine probability area (SPA). The computing node 216 calculates the coverage angle of the next dipping pattern considering the attributes of the first dipping pattern. The computing node 216 can determine a sequence of dipping pattern, wherein the computation mode configured in the submarine search system.
[0048] The graphical user interface (GUI) 218 is deployed on a screen to display the sequence of dipping positions computed by the computation node 216, wherein the sequence of dipping positions calculated by the submarine search system 208 is sent to the aerial unit 202 to search the submarine.
[0049] The datum detection gap time for the calculation of the first dipping pattern coordinate improves the submarine detection probability. The datum is the last known position of the submarine which is under search operation in the form of latitude and longitude. The gap time is the time after reporting the submarine contact lost and the actual aerial unit take off time for the mission. The submarine is moving towards the platform which reduces the distance travelled by the aerial unit before the first dipping pattern which maximizes the probability of detection of the submarine in the SSW mission. The coverage angle is calculated by lines drawn from the datum position to the intersection points of the dipping sonar detection circle and the SPA, wherein the area for submarine search is covered between tangential to SPA and the intersection point with SPA The dipping sonar detection circle is created by the radius of the dipping sonar.
[0050] FIG. 3 illustrates an exemplary flow diagram of the SSW computation node, in accordance with an embodiment of the present disclosure.
[0051] The SSW computation mode 106 for submarine detection follows the steps mentioned in FIG. 3. FIG. 3 starts with the location (known as the datum) of the suspected target 302 and the time of the detection of the same received from the external source as defined in data 212. The SSW computation mode 106 collects the attributes 304 required for calculation. The attributes may be as follows:
• Area of Uncertainty (AoU) : Circumference of a circle growing bigger as time passes since the submarine is moving away from the datum
• Speed of aerial unit
• Speed of submarine (a) Minimum submarine submerged speed (u_min) (b) Maximum submarine submerged speed (u_max)
• Time delay in dipping sonar is referred as Dipping time (delta_t)
• Radius of sonar detection system referred as the Sonar detection range (r)
[0052] The attributes for calculation are provided by the hardware node mentioned in user interface 108. The SSW computation mode 106 starts with the execution 306 of aerial unit dipping sonar search pattern method considering all the attributes described above.
[0053] The SSW computation mode 106 indicates the first dipping pattern 308 found which is mentioned in calculated dipping position 214 in the implementation as mentioned in the execution 306. The first dipping pattern 308 found is stored in the hardware node (also referred to as database 210 in FIG. 2. The SSW computation mode 208 starts with the implementation of the method to calculate the coverage angle of the next dip considering the attributes of the first dip pattern 308 It considers the previous dip radius (R) for the calculation of the next dip for the next dip calculation.
[0054] The SSW computation mode 208 indicates the next dipping pattern 310 found which is mentioned in FIG. 2 as per the calculated coverage angle mentioned in the next coverage angle calculation 312. The first dipping pattern 308 found is stored in hardware node 216 mentioned in for next dip calculation 312.
[0055] The steps are repeated periodically 314 till the endurance of the aerial unit i.e., the step may be repeated if the total time in the search pattern from the first dipping pattern 308 to the next dipping pattern 310 < endurance of the aerial unit.
[0056] FIG. 4 illustrates an exemplary view of the coverage angle calculation tangential from the centre of the circumference of the datum, in accordance with an embodiment of the present disclosure.
[0057] Referring to FIG. 4, the time taken 402 by the aerial unit to reach the first dip position from the platform position which is labelled as “T”. The sonar detection range 404 is labelled as “r”
[0058] R = * T is depicted in 406. The conventional coverage angle 408 is calculated as 2*sin-1(r/R).
[0059] The detection of the submarine (410, 412) in the search dip found as per the claimed coverage angle. The miss of the submarine (414, 416) in the search dip found as per the claimed coverage angle.
[0060] FIG. 5 illustrates an exemplary view of the coverage angle calculation as per intersection points of circumference of datum and detection, in accordance with an embodiment of the present disclosure. As shown in FIG. 5, the intersection points of the circumference of datum circle 502 and dip circle 504 are depicted.
[0061] The coverage angle 506 is calculated as 2*cos-1(1-(r*r)/(2*R*R)). The coverage angle is the angle subtended by intersection points of the sonar detection circle and FOC on the FOC centre. Where r is the same as defined in (FIG. 4, 404) and R is the same as defined in (FIG. 4, 406).
[0062] The submarines which were shown as missed in FIG. 4 may be detected in one of the dips if the calculation of coverage angle is as per FIG. 5.
[0063] FIG. 6 illustrates an exemplary view of the two different approaches to search the first dip, in accordance with an embodiment of the present disclosure.
[0064] FIG. 6 depicts two different approaches to start the search pattern. It calculates the first intersection point of the aerial unit and datum taking into consideration two different courses of movement of the datum.
[0065] Approach 1 is the conventional method of course calculation of datum which is depicted in the prior art and Approach 2 is the novel method of course calculation which is a modification of Approach 1.
[0066] The assumption of movement of datum 602 in the true north direction (course = 0) is depicted.
[0067] The movement of aerial unit 604 in the assumed direction of the course of the submarine. It calculates the time taken to reach the first intersection point to cover the distance which is labelled as “D1” from the Platform position to the first intersection point as follows:
Time for first dip, T1 = D1/Aerial_Unit_speed
[0068] The first intersection point of datum 606 and aerial unit is taken into consideration the datum moves in the true north direction (course = 0).
[0069] The movement of aerial unit 610 in the direction of the course of the submarine. It calculates the time taken to reach the first intersection point to cover a distance which is labelled as “D2” from the Platform position to the first intersection point as follows assumption of movement of datum 608 towards the platform is depicted.
Time for first dip, T2 = D2/ Aerial_Unit_speed
[0070] The first intersection point of datum 612 and the aerial unit is taken into consideration the datum moves towards the direction of the platform.
[0071] D1 is greater than D2 i.e., the distance travelled by the aerial unit in approach 1 is greater than the distance travelled by the aerial unit in approach 2. So, the time for the first dip in approach 1 is greater than the time for the first dip in approach 2.
[0072] Following parameters are taken for calculation in Approach 1 and Approach 2:
sub_speed = Average of minimum submarine submerged speed and maximum submarine submerged speed
datumGapSec = Gap time in seconds between datum creation date time and current date time
Platform_pos = (X,Y) coordinates of Platform
helo_speed = Speed of aerial unit
[0073] The conventional method approach is shown in FIG.6, Approach 1: Whereby it is assumed that the submarine is moving along the true north direction for the first dip calculation
[0074] I. Calculate the following parameters for the quadratic equation:
a = sub_speed*sub_speed - helo_speed*helo_speed;
b = 2*(sub_speed*sub_speed*datumGapSec-Platform_pos.y*sub_speed);
c=sub_speed*sub_speed*datumGapSec*datumGapSec-2*sub_speed*datumGapSec*Platform_pos.y+Platform_pos.y*Platform_pos.y + Platform_pos.x*Platform_pos.x.
[0075] Solve the quadratic equation taking into consideration parameters a,b and c as calculated in step I to calculate the time of the first intersection which is taken as “t_i”
[0076] X position of first intersection point = 0 //As the calculation is done taken into consideration submarine moves in the true north axis.
[0077] Y position of first intersection point = sub_speed*t_i+sub_speed*datumGapSec.
[0078] The novel method approach (FIG.6, Approach 2): Whereby it is assumed that the submarine is moving towards the platform for the first dip calculation.
[0079] I. Calculate initial_angle = Angle made by Platform vector with X-axis.
[0080] X position of first intersection point = cosine(initial_angle)*sub_speed*datumGapSec+Platform_pos.x *(sub_speed/(sub_speed+helo_speed))
[0081] Y position of first intersection point = sine(initial_angle)*sub_speed*datumGapSec+Platform_pos.x *(sub_speed/(sub_speed+helo_speed))
[0082] FIG. 7 illustrates an exemplary view of the two different practical approaches to search the first dip, in accordance with an embodiment of the present disclosure. FIG. 7 depicts two different practical approaches to start the search pattern same as explained in FIG. 6. This diagram is taken from the simulation display for algorithm testing. Here big circles indicate dips of sonar and small circles indicate submarine position on all possible courses. The origin of the axis is the last known position of the submarine (datum). The position of the platform (702, 706) is exactly the same. The first intersection point of submarine 704 and aerial unit 708 same as explained in (FIG. 6, 606) and (FIG. 6, 612) respectively.
[0083] Continuous search patterns over an expanding circle make the spiral formation with a shape dictated by the velocity of the submarine which is shown in FIG. 7. As our search is discrete and complex, we must determine where on the spiral to the next dip which is explained in FIG. Following a dip, the aerial unit can travel a short distance and dip again, in which case the coverage of the second dip is relatively large. The coverage angle calculation in the current invention is explained in FIG. 5.
[0084] The Dipping Sonar Search Pattern method works as follows:
• Calculate the gap time in seconds (gapSec) between the datum creation date time and current date time.
• Calculate the first intersection point of the velocity of the aerial unit (consider the course of submarine) and the velocity of the datum (the assumption is submarine runs towards the platform and the speed is the average of the minimum speed of the submarine and a maximum speed of submarine).
• The intersection point may be considered as a center of the first dip. So, the first dip search starts at the line joining datum and submarine not at zero courses.
• Calculate the coverage angle of the next dip as per the first dip parameters found in step 3 and check for possibility. If the solution is not possible, then raise the error and exit otherwise save the next dip parameters. The coverage angle calculation is explained in the following sections.
• Repeat step 4 considering the previous dip parameters.
• Calculate the probability of detection in each dip and sum up the probability at the end of the search pattern implementation.
• Start moving the aerial unit after the search pattern implementation is completed
[0085] FIG. 8 illustrates an exemplary view of the series of consecutive dipping points for the dipper, in accordance with an embodiment of the present disclosure.
[0086] FIG. 8 indicates a dipping pattern which is a series of consecutive dipping points for the dipper. A continuous dipping search pattern over an expanding circle forms a spiral shape. Following a dip, the aerial unit travels a short distance and dip again as per the series of the search pattern.
Where, a previous dip radius 802 is labelled as “R1”.
a sonar detection range 804 which is labelled as “r”
a distance travelled by the aerial unit from the previous dip circle to the next consecutive dip circle 806 which is calculated as v*t where “v” is aerial unit speed and “t” is the time gap between consecutive dips.
a next dip radius 808 which is labelled as “R2” and calculated as R2 = R1 + u(t+dip_time) where “u” is submarine speed and “dip_time” is the time for which sonar has to be dipped for successful detection.
[0087] It is assumed that the submarine speed may be provided by the source of information of the datum. If submarine speed is unknown, then the algorithm may not be implemented. Submarine speed is basically taken as the average of the minimum speed of submarine and the maximum speed of the submarine.
[0088] The equation to calculate series of consecutive dipping points for the dipper which is defined in FIG.8.
ϴ = cos-1(1-(r*r)/(2*R1*R1)) (ϴ is displayed in FIG. 8)
α = cos-1(1-(r*r)/(2*R2*R2)) (α is displayed in FIG. 8)
R12+ R22– 2*R1*R2*cos(α+ ϴ)- v2 t2 = 0
It can be written as R12+ R22– 2*R1*R2*cos(cos-1(1-(r*r)/(2*R1*R1))+ cos-1(1-(r*r)/(2* R1 + u(t+dip_time) * R1 + u(t+dip_time))))- v2 t2 = 0
[0089] In the above equation, t is the only unknown variable. Solving this equation for t gives us time for the next dip. R2 (Radius of next dip) using the value of t is calculated.
α using the value of R2 is calculated. When knowing R2, ϴ and α, the location of next dip (as per FIG. 8) is known.
Where, r – Sonar detection Range
R1 – Previous dip radius
R2 - Next dip radius
v – Aerial unit speed
t – Time gap between consecutive dips
dip_time - The time for which sonar has to be dipped for successful detection
[0090] The equation to calculate the radius of the submarine probability area:
[0091] Radius Submarine Probability Area = sub_speed * time elapsed after reporting of the datum
[0092] FIG. 9 illustrates an exemplary graphical view of the effect of sonar detection range on the probability of detection, in accordance with an embodiment of the present disclosure. FIG. 9 depicts how the probability of detection grows with respect to the sonar detection range. It is clear from the figure that the probability of detection is comparatively less in the conventional method than in the novel method of calculation.
[0093] FIG. 10 illustrates an exemplary graphical view of the effect of aerial unit speed on the probability of detection, in accordance with an embodiment of the present disclosure. FIG. 10 depicts how the probability of detection grows with respect to the speed of the aerial unit. It is clear from the figure that the probability of detection is comparatively less in the conventional method than in the novel method of calculation.
[0094] FIG. 11 illustrates an exemplary graphical view of the effect of average submarine speed on the probability of detection, in accordance with an embodiment of the present disclosure. FIG. 11 depicts how the probability of detection shrinks with respect to the average speed of the submarine. It is clear from the figure that the probability of detection is comparatively less in the conventional method than the novel method of calculation. The submarine search operation is simulated to test the algorithm and the graphs mentioned in FIG. 9, 10 and 11 are obtained from the calculated values.
[0095] FIG. 12 illustrates an exemplary flow chart of the method for dipping sonar search pattern, in accordance with an embodiment of the present disclosure.
[0096] Referring to FIG. 12, method 1200 includes block 1202, the aerial unit is equipped with dipping sonar defined as a dipper in SSW mission to detect, track, acquire a target submarine, the aerial unit transfers a set of data to a submarine search system.
[0097] At block 1204, the SSW computation node collects a set of attributes required for the calculation of the dipping position to determine a first dipping pattern. At block 1206, the SSW computation node is configured to receive the set of data from the submarine search system. At block 1208, the SSW computation node utilizes the datum detection gap time for the first dipping pattern assuming the submarine movement direction towards the platform and takes the coverage angle by lines drawn from the datum position to the intersection points of the dipping sonar detection circle and submarine probability area (SPA).
[0098] At block 1210, the SSW computation node calculates the coverage angle of the next dipping pattern considering the attributes of the first dipping pattern. At block 1212, the SSW computation mode is configured in the submarine search system and configured to determine a sequence of dipping positions. At block 1214, the GUI is deployed on a screen to display the sequence of dipping positions computed by the computation node, wherein the sequence of dipping positions calculated by the submarine search system is sent to the aerial unit to search the submarine.
[0099] It will be apparent to those skilled in the art that the system 100 of the disclosure may be provided using some or all of the mentioned features and components without departing from the scope of the present disclosure. While various embodiments of the present disclosure have been illustrated and described herein, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the disclosure, as described in the claims.

ADVANTAGES OF THE PRESENT INVENTION
[00100] The present invention provides a system that optimizes the operation of the aerial unit.
[00101] The present invention provides a system that develops an effective way to deploy the dipping sonar.
[00102] The present invention provides a system that develops an effective dipping pattern to maximize the probability of detection of the submarine in SSW missions.
[00103] The present invention provides a system that develops the effective coverage angle of next dipping pattern of sonar to maximize coverage of submarines.
, Claims:1. A system (100) for dipping sonar search patterns, the system comprising:
an aerial unit (202) equipped with dipping sonar (204) defined as a dipper in sub surface warfare (SSW) mission to detect, track, acquire and attack a target submarine, the aerial unit transfers a set of data to a submarine search system (208), the submarine search system comprising:
a computation node (216) configured to determine a sequence of dipping positions, the computation node configured to:
collect a set of attributes required for the calculation of the dipping position to determine a first dipping pattern;
receive the set of data from the submarine search system (208);
utilizes the datum detection gap time for the first dipping pattern assuming the submarine movement direction towards platform and takes the coverage angle by lines drawn from the datum position to the intersection points of the dipping sonar detection circle and submarine probability area (SPA);
calculate the coverage angle of the next dipping pattern considering the set of attributes of the first dipping pattern;
determine a sequence of dipping pattern, wherein the computation mode configured in the submarine search system; and
a graphical user interface (GUI) (218) is deployed on a screen to display the sequence of dipping positions computed by the computation node (216), wherein the sequence of dipping positions calculated by the submarine search system is sent to the aerial unit to search the target submarine.
2. The system as claimed in claim 1, wherein the set of data pertains to datum last position, time of detection of datum, aerial unit speed, and speed of submarine.
3. The system as claimed in claim 1, wherein the set of attributes pertain to area of uncertainty (AoU), speed of aerial unit, speed of submarine, dipping time and sonar detection range.
4. The system as claimed in claim 1, wherein the datum detection gap time for the calculation of the first dipping pattern coordinate improves the submarine detection probability.
5. The system as claimed in claim 1, wherein the datum is the last known position of the submarine which is under search operation in the form of latitude and longitude.
6. The system as claimed in claim 1, wherein the gap time is the time after reporting of the target submarine contact lost and actual aerial unit take off time for the mission, wherein the relation between co-ordinates of first dip and gap time is as follows:
Calculate initial_angle = Angle made by Platform vector with X-axis.
X position of first intersection point = cosine(initial_angle)*sub_speed*datumGapSec+Platform_pos.x *(sub_speed/(sub_speed+helo_speed))
Y position of first intersection point = sine(initial_angle)*sub_speed*datumGapSec+Platform_pos.x *(sub_speed/(sub_speed+helo_speed))
where,
sub_speed = Average of minimum submarine submerged speed and maximum submarine submerged speed
datumGapSec = Gap time in seconds between datum creation date time and current date time
Platform_pos = (X,Y) coordinates of Platform
helo_speed = Speed of aerial unit
7. The system as claimed in claim 1, wherein the target submarine is moving towards the platform which reduces the distance travelled by the aerial unit before the first dipping pattern which maximizes the probability of detection of the target submarine in the SSW mission.
8. The system as claimed in claim 1, wherein the coverage angle is calculated by lines drawn from the datum position to the intersection points of the dipping sonar detection circle and the SPA, wherein the area for the target submarine search is covered between tangential to SPA and intersection point with SPA, wherein the equation to calculate series of consecutive dipping points for the dipper which is as follows:
ϴ = cos-1(1-(r*r)/(2*R1*R1))
α = cos-1(1-(r*r)/(2*R2*R2))
R12+ R22 – 2*R1*R2*cos(α+ ϴ)-v2 t2 = 0
It can be written as
R12+ R22 – 2*R1*R2*cos(cos-1(1-(r*r)/(2*R1*R1))+ cos-1(1-(r*r)/(2* R1 + u(t+dip_time) * R1 + u(t+dip_time))))-v2 t2 = 0
Where,
r – Sonar detection Range
R1 – Previous dip radius
R2 - Next dip radius
v – Aerial unit speed
t – Time gap between consecutive dips
dip_time - Time for which sonar has to be dipped for successful detection
9. The system as claimed in claim 1, wherein the dipping sonar detection circle is created by the radius of the dipping sonar.
10. A method (1200) for dipping sonar search pattern, the method comprising:
equipping (1202) an aerial unit with dipping sonar defined as a dipper in SSW mission to detect, track, acquire target submarine, the aerial unit transfer a set of data to a submarine search system;
collecting (1204), by a computation node, a set of attributes required for calculation of the dipping position to determine a first dipping pattern;
receiving (1206), by the computation node, the set of data from the submarine search system;
utilizing (1208) the datum detection gap time for the first dipping pattern assuming the submarine movement direction towards platform and takes the coverage angle by lines drawn from the datum position to the intersection points of the sonar detection circle and submarine probability area (SPA);
calculating (1210), by the computation node, the coverage angle of the next dip considering the attributes of the first dipping pattern;
determining (1212), by the computation node, a sequence of dipping pattern, wherein the computation mode configured in the submarine search system;
deploying (1214) a graphical user interface (GUI) on a screen to display the dipping pattern computed by the computation mode, wherein the dipping position calculated by the submarine search system is send to the aerial unit which follows the dipping position to search the target submarine.