A Calculation Method for the Penetration Expectation of Anti-Ship Missiles Based on Improved Graphical Analysis Method
By improving the graphical analysis method, combining the technical and tactical indicators of the various defense systems of anti-ship missiles and surface ships, the penetration expectations when the anti-ship missile attacks surface ships are calculated, which solves the problem that it is difficult to effectively calculate the anti-ship missile's penetration expectations in the existing technology, and provides a concise penetration decision-making auxiliary solution.
Patent Information
- Application Number
- CN202210747732.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-06-28
- Publication Date
- 2025-06-03
- Estimated Expiration
- 2042-06-28
AI Technical Summary
The existing technology is difficult to effectively calculate the penetration expectations when anti-ship missiles attack surface ships, and it is impossible to directly obtain the actual penetration expectations when anti-ship missiles attack surface ships.
Using an improved graphical analysis method, the target elements of the anti-ship missile and the technical and tactical indicators of the surface ship's defense system are determined, the time-distance coordinate system is established, and the offensive and defense situation chart is drawn. Combined with the killing probability and interference probability of ship-to-air missiles, ship-based artillery and electronic warfare systems, the penetration expectation of anti-ship missiles is calculated.
It provides a concise and intuitive penetration solution for anti-ship missile penetration decisions, assists the commander in making decisions on the air, and improves the probability calculation ability of anti-ship missile penetration.
Smart Images
Figure CN115080920B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of anti-ship missile penetration auxiliary decision-making, and particularly relates to a method for calculating the penetration expectation of an anti-ship missile based on an improved graphical analysis method. Background Art
[0002] For the firing command of an anti-ship missile, the commander needs to comprehensively evaluate various factors such as the dynamically changing battlefield situation and the defense capabilities of the target ship, and decide on the firing element parameters of the missile to complete the missile firing.
[0003] Whether the anti-ship missile can break through the defense system of the target ship at the end of the attack is the key directly affecting the completion of the combat mission. This requires the commander to have strong firing command capabilities, and achieve the firing command of the anti-ship missile through scientific and reasonable decision-making, so as to avoid failing to achieve the ideal firing result due to the complex combat environment and ad hoc experience-based command decisions.
[0004] The literature "Method for Evaluating the Firing Efficiency of Ship-to-Air Missiles Based on Graphical Analysis" proposes a method for determining the number of shots of a ship-to-air missile weapon system against a group of targets through graphical analysis. The graphical analysis method uses the motion characteristics of the aerial group targets and the relevant elements of the ship-to-air missile weapon system to determine the number of shots of the ship-to-air missile weapon system against the group of targets and the kill probability for a single target. The specific steps include: (1) determining the target elements and the elements of the ship-to-air missile weapon system; (2) establishing a distance-time coordinate system, with the horizontal axis representing time and the vertical axis representing the distance between the target and the ship-to-air missile; (3) drawing the kill zone of the ship-to-air missile; (4) drawing the motion trajectories of the group of targets; (5) drawing the motion trajectory of the ship-to-air missile; (6) determining the number of shots of the ship-to-air missile and the kill probability for a single target. This literature is mainly used to determine the number of shots of the ship-to-air missile weapon system against a group of targets. For an anti-ship missile to penetrate a surface ship, the anti-ship missile faces not only the ship-to-air missile weapon system, but also the electronic warfare system and the shipborne artillery weapon system. Using the graphical analysis method described in this reference, the actual penetration expectation of the anti-ship missile when attacking a surface ship cannot be directly obtained. Summary of the Invention
[0005] In view of the realistic combat problems faced by anti-ship missiles in attacking surface ships, the present invention proposes a method for calculating the penetration expectation of an anti-ship missile based on an improved graphical analysis method. The main technical solution is as follows:
[0006] A method for calculating the penetration expectation of an anti-ship missile based on an improved graphical analysis method includes the following steps:
[0007] Step S1: Determine the target elements of the anti-ship missile.
[0008] Step S2: Analyze the main factors affecting the defense effectiveness in the surface ship electronic warfare system, ship-to-air missile weapon system, and shipborne artillery weapon system, and determine the main technical and tactical indicators of each defense system of the surface ship.
[0009] Step S3: Establish a coordinate system with time as the horizontal axis and the distance between the anti-ship missile and the surface ship as the vertical axis, and draw the initial attack and defense situation diagram.
[0010] Step S4: According to the main technical and tactical indicators of the surface ship ship-to-air missile weapon system and shipborne artillery weapon system, draw the defense trajectory diagrams of the ship-to-air missile weapon system and shipborne artillery weapon system against the hard anti-aircraft of the anti-ship missile in sequence.
[0011] Step S5: Analyze and determine the number of times of hard anti-aircraft of the ship-to-air missile weapon system and shipborne artillery weapon system against the anti-ship missile based on the graphics drawn in Step S4, and calculate the penetration expectation of the anti-ship missile by combining the kill probability of the ship-to-air missile and shipborne artillery and the interference probability of the electronic warfare system against the anti-ship missile.
[0012] Further, in Step S1, the target elements include the number of anti-ship missile targets, the time interval between two adjacent single targets in the anti-ship missile, and the velocity vector of the anti-ship missile.
[0013] Further, in Step S2, the technical and tactical indicators of the surface ship electronic warfare system include: the near interference boundary and far interference boundary of the electronic warfare system at the flight altitude of the anti-ship missile, the horizontal distance at which the early warning and detection system can reliably detect the target, and the interference success rate of the electronic warfare system for each target in the same wave of targets.
[0014] Further, in Step S2, the technical and tactical indicators of the ship-to-air missile weapon system include: the near kill zone boundary and far kill zone boundary at the flight altitude of the anti-ship missile, the velocity vector of the ship-to-air missile flight, the number of available target channels of the ship-to-air missile weapon system for air incoming targets, the combat reaction time of the ship-to-air missile weapon system, the transfer fire shooting time of the ship-to-air missile weapon system, the time interval between two shootings organized by two adjacent channels of the ship-to-air missile weapon system, the number of missiles launched each time by the ship-to-air missile weapon system, and the single-shot hit probability of the ship-to-air missile.
[0015] Further, in Step S2, the technical and tactical indicators of the shipborne artillery weapon system include: the near kill zone boundary and far kill zone boundary at the flight altitude of the anti-ship missile, the velocity vector of the shipborne artillery ammunition flight, the combat reaction time of the shipborne artillery weapon system, the time interval between two shootings of the shipborne artillery weapon system, and the single-shot anti-aircraft hit probability of the shipborne artillery weapon system.
[0016] Further, the specific steps of Step S3 are as follows:
[0017] S31: Draw the distance at which the detection and early warning system can reliably detect the target.
[0018] S32: Draw the near interference boundary and far interference boundary of the electronic warfare system at the flight altitude of the anti-ship missile.
[0019] S33: Draw the near kill zone boundary and far kill zone boundary of the ship-to-air missile weapon system at the flight altitude of the anti-ship missile.
[0020] S34: Draw the near kill zone boundary and far kill zone boundary of the shipborne artillery weapon system at the flight altitude of the anti-ship missile.
[0021] S35: Calculate the movement trajectories of each anti-ship missile according to the number, interval and velocity vector of the anti-ship missiles, and draw the flight trajectory diagram of the anti-ship missiles.
[0022] Further, the specific drawing method of the defense trajectory diagram of the ship-to-air missile weapon system against anti-ship missiles in step S4 is as follows:
[0023] S41: Allocate target channels to each anti-ship missile in turn according to the available target channel number of the ship-to-air missile weapon system (allocation rules: ① Among the anti-ship missiles in the same wave, those not resisted by the ship-to-air missiles are given priority; ② For those above the same, those with a closer distance between the anti-ship missile and the surface ship are given priority), calculate the movement trajectory of the ship-to-air missile at the first shot of the jth target channel, j = 1, 2,..., K m , combined with the interval time between two shots organized by two adjacent channels of the ship-to-air missile weapon system, draw the flight trajectory diagram of the ship-to-air missile.
[0024] S42: Draw the flight trajectory diagram of the ship-to-air missile at the next shot of the jth target channel according to the retargeting shooting time of the ship-to-air missile weapon system.
[0025] S43: Repeat step S42 until the movement trajectory of the ship-to-air missile cannot intersect with the anti-ship missile in the kill zone.
[0026] Further, the specific drawing method of the defense trajectory diagram of the shipborne artillery weapon system against anti-ship missiles in step S4 is as follows:
[0027] S44: According to the combat reaction time P of the shipborne artillery weapon system t and the flight speed V of the shipborne artillery ammunition p (t), determine the shipborne artillery resistance situation (allocation rules: ① Among the anti-ship missiles in the same wave, those not resisted by the shipborne artillery are given priority; ② For those above the same, those with a closer distance between the anti-ship missile and the surface ship are given priority), draw the flight trajectory diagram of the shipborne artillery ammunition (if the time from zero moment to the time when the anti-ship missile reaches the far kill zone boundary of the shipborne artillery weapon system is greater than the sum of the combat reaction time P of the shipborne artillery weapon system t and the flight time of the shipborne artillery ammunition, then the shipborne artillery ammunition encounters the anti-ship missile at the far kill zone boundary).
[0028] S45: Determine whether the naval gun ammunition for the next engagement will intersect with the anti-ship missile within the kill zone based on the time interval between two shots of the naval gun, the flight speed of the naval gun ammunition, and the speed of the anti-ship missile. If there is an intersection, draw a flight trajectory diagram of the naval gun ammunition for the next engagement.
[0029] S46: Repeat step S45 until the movement trajectory of the naval gun ammunition cannot intersect with the anti-ship missile within the kill zone.
[0030] Further, the specific steps in step S5 are as follows:
[0031] S51: Calculate the penetration probability of each anti-ship missile according to the technical and tactical indicators of the electronic warfare system.
[0032] S52: Calculate the penetration probability of each anti-ship missile according to the technical and tactical indicators of the ship-to-air missile weapon system and the actual engagement situation.
[0033] S53: Calculate the penetration probability of each anti-ship missile according to the technical and tactical indicators of the naval gun weapon system and the actual engagement situation.
[0034] S54: Calculate the penetration expectation of the anti-ship missile stream.
[0035] The beneficial effects of the present invention are as follows: The application scenario of the traditional graphical analysis method in the present invention is extended from the design effectiveness evaluation of the ship-to-air missile weapon system to the calculation of the penetration probability of anti-ship missiles against surface ships, providing a simple and intuitive penetration plan for anti-ship missile penetration decision-making and assisting the commander in making on-the-spot decisions. BRIEF DESCRIPTION OF THE DRAWINGS
[0036] Figure 1 is the basic flowchart.
[0037] Figure 2 is the offensive and defensive situation diagram at the initial moment.
[0038] Figure 3 is the offensive and defensive situation diagram of the first shot of the ship-to-air missile.
[0039] Figure 4 is the offensive and defensive situation diagram of the second shot of the ship-to-air missile.
[0040] Figure 5 is the offensive and defensive situation diagram of the fourth shot of the ship-to-air missile.
[0041] Figure 6 is the offensive and defensive situation diagram of the first engagement of the naval gun weapon system. DETAILED DESCRIPTION OF THE INVENTION
[0042] The following further elaborates on the embodiments of the present invention in conjunction with the accompanying drawings and technical solutions. It should be noted that the exemplary embodiments can be implemented in various forms and should not be construed as being limited to the embodiments described herein; the exemplary embodiments can more comprehensively convey the concept of the present invention to those skilled in the art of engineering and technology.
[0043] Referring to Figures 1-6 , the present invention proposes a method for calculating the penetration expectation of an anti-ship missile based on an improved graphic analysis method. The actual penetration expectation process of the anti-ship missile against a surface ship using this method is as follows:
[0044] Step 1: Determine the target elements of the anti-ship missile and the technical and tactical indicators of the surface ship's electronic warfare system, ship-to-air missile weapon system, and shipborne artillery weapon system, specifically:
[0045] (1) Determine the target elements of the anti-ship missile: The number of anti-ship missile targets M t = 9; The time interval T between two adjacent single targets in the anti-ship missile t = 2 s; The speed V of the anti-ship missile t (t) = 280 m / s, and the speed direction is directly towards the surface ship.
[0046] (2) Determine the technical and tactical indicators of the surface ship's electronic warfare system: At the flight altitude of the anti-ship missile, the interference near boundary D of the electronic warfare system min = 0 km, the interference far boundary D max = 23 km; The horizontal distance D at which the early warning detection system can reliably detect the target f = 25 km; The interference success rate D of the electronic warfare system for the i-th target in the same wave of targets pi = max(0.8 - 0.2i, 0).
[0047] (3) Technical and tactical indicators of the ship-to-air missile weapon system: At the flight altitude of the anti-ship missile, the kill zone near boundary K of the ship-to-air missile weapon system min = 3.5 km, the kill zone far boundary K max = 20 km; The flight speed V of the ship-to-air missile K (t) = 750 m / s, and the speed direction is directly towards the incoming anti-ship missile; The available target channels K of the ship-to-air missile weapon system for incoming air targets m = 2; The operational reaction time K of the ship-to-air missile weapon system t = 16 s; The transfer fire shooting time K of the ship-to-air missile weapon system z = 21 s; The interval time K between two shootings organized by two adjacent channels of the ship-to-air missile weapon system τ = 2 s; The number of missiles launched each time by the ship-to-air missile weapon system K n = 2; The single-shot hit probability K of the ship-to-air missile p= 0.5.
[0048] (4) Technical and tactical indicators of shipborne gun weapon system: The near boundary P of the kill zone of the shipborne gun weapon system at the flight altitude of the anti-ship missile min = 0 km, the far boundary P of the kill zone max = 1.5 km; The flight speed V of the shipborne gun ammunition p (t) = 600 m / s; The combat reaction time P of the shipborne gun weapon system t = 3 s; The interval time P between two shootings of the shipborne gun weapon system z = 8 s; The single-shot hit probability P of the shipborne gun weapon system p = 0.5.
[0049] Step 2: Establish a distance-time coordinate system, with the horizontal axis representing time and the vertical axis representing the distance between the target and the surface ship. The zero moment on the horizontal axis corresponds to the moment when the early warning detection system reliably discovers the target.
[0050] Step 3: Draw the horizontal distance D at which the detection and early warning system reliably discovers the target f .
[0051] Step 4: Draw the interference near boundary D of the electronic warfare system at the flight altitude of the anti-ship missile min , the interference far boundary D max .
[0052] Step 5: Draw the near boundary K of the kill zone of the ship-to-air missile weapon system at the flight altitude of the anti-ship missile min , the far boundary K of the kill zone max .
[0053] Step 6: Draw the near boundary P of the kill zone of the shipborne gun weapon system at the flight altitude of the anti-ship missile min , the far boundary P of the kill zone max .
[0054] Step 7: According to the number M of anti-ship missiles t , the interval T t and the velocity vector V t (t), calculate the movement trajectories of each anti-ship missile and draw the anti-ship missile flight trajectory diagram; If the magnitude and direction of V t (t) remain unchanged, the initial moment attack and defense situation diagram is as Figure 2 shown.
[0055] Step 8: According to the available target channel number K of the ship-to-air missile weapon system m successively allocate target channels to each anti-ship missile, calculate the movement trajectory of the ship-to-air missile when the jth target channel fires for the first time and draw the flight trajectory diagram of the ship-to-air missile; In this example, Vk (t) remains unchanged in size and direction. The offense-defense situation during the first firing of the ship-to-air missile is as Figure 3 shown.
[0056] Step 9: Draw the flight trajectory diagram of the ship-to-air missile during the next firing of the j-th target channel. The offense-defense situation during the second firing of the ship-to-air missile is as Figure 4 shown.
[0057] Step 10: Repeat Step 9 until the movement trajectory of the ship-to-air missile cannot intersect with the anti-ship missile in the kill zone. In this example, the ship-to-air missile can fire four times in both firing channels. At this time, the offense-defense situation diagram is as Figure 5 shown.
[0058] Step 11: Determine the engagement situation of the shipborne gun based on the combat response time P t of the shipborne gun weapon system and the flight speed V p (t) of the shipborne gun ammunition, and draw the flight trajectory diagram of the shipborne gun ammunition; in this example, V p (t) remains unchanged in size and direction, then the flight trajectory diagram of the shipborne gun ammunition is as Figure 6 shown (if the time from the zero moment to the time when the anti-ship missile reaches the far boundary of the kill zone of the shipborne gun weapon system is greater than the sum of the combat response time P t of the shipborne gun weapon system and the flight time of the shipborne gun ammunition, then the shipborne gun ammunition will encounter the anti-ship missile at the far boundary of the kill zone).
[0059] Step 12: Judge whether the shipborne gun ammunition for the next engagement will intersect with the anti-ship missile in the kill zone based on the interval time P z between two firings of the shipborne gun, the flight speed V p (t) of the shipborne gun ammunition, and the speed V t (t) of the anti-ship missile. If they intersect, then draw the flight trajectory diagram of the shipborne gun ammunition for the next engagement; in this example, the shipborne gun can only engage once.
[0060] Step 13: Repeat Step 12 until the movement trajectory of the shipborne gun ammunition cannot intersect with the anti-ship missile in the kill zone.
[0061] Step 14: Calculate the penetration probability of each anti-ship missile and the penetration expectation of the anti-ship missile stream according to the interference success rate D pi of the i-th target in the same wave of targets by the electronic warfare system, the single-shot hit probability K p of the ship-to-air missile, and the single-engagement hit probability P p of the shipborne gun weapon system. Specifically:
[0062] (1) According to the technical and tactical indicators of the electronic warfare system, in this example, the electronic warfare system can interfere with the first 3 anti-ship missiles. At this time, the penetration probability P of each anti-ship missilei dzz = 1 - D pi = 1 - max(0.8 - 0.2i, 0), which are: 0.4, 0.6, 0.8, 1, 1, 1, 1, 1, 1.
[0063] (2) According to the technical and tactical indicators of the ship-to-air missile weapon system and the actual combat situation, the penetration probability P of anti-ship missiles after the double-shot salvo of ship-to-air missiles in this example jk = 1 - (1 - K p 2 ) = 1 - (1 - 0.5 2 ) = 0.25. The first 8 anti-ship missiles are all subjected to the double-shot salvo of ship-to-air missiles. At this time, the penetration probabilities of each anti-ship missile are respectively: 0.1, 0.15, 0.2, 0.25, 0.25, 0.25, 0.25, 0.25, 1.
[0064] (3) According to the technical and tactical indicators of the shipborne gun weapon system and the actual combat situation, the shipborne gun conducts 1 strike on the 9th anti-ship missile in this example. At this time, the penetration probabilities of each anti-ship missile are respectively: 0.1, 0.15, 0.2, 0.25, 0.25, 0.25, 0.25, 0.25, 0.5.
[0065] (4) Calculate the penetration expectation of the anti-ship missile stream .
Claims
1. A method for calculating the penetration expectation of an anti-ship missile based on an improved graphic analysis method, characterized in that, the method comprises the following steps: Step S1: Determine the target elements of the anti-ship missile; Step S2: Analyze the factors affecting the defense effectiveness in the surface ship's electronic warfare system, ship-to-air missile weapon system, and shipborne artillery weapon system, and determine the technical and tactical indicators of each defense system of the surface ship; Step S3: Establish a coordinate system with time as the horizontal axis and the distance between the anti-ship missile and the surface ship as the vertical axis, and draw the initial attack and defense situation diagram; Step S4: According to the technical and tactical indicators of the surface ship's ship-to-air missile weapon system and shipborne artillery weapon system, draw the defense trajectory diagrams of the ship-to-air missile weapon system and the shipborne artillery weapon system against the hard anti-attack of the anti-ship missile in sequence; The specific drawing method is as follows: S41: Allocate target channels to each anti-ship missile in sequence according to the number of available target channels of the ship-to-air missile weapon system, and calculate the trajectory of the ship-to-air missile at the first shot of the j-th target channel, where j = 1, 2, …, K m , combine the interval time between two shots organized by two adjacent channels of the ship-to-air missile weapon system, and draw the flight trajectory diagram of the ship-to-air missile; S42: According to the transfer fire shooting time of the ship-to-air missile weapon system, draw the flight trajectory diagram of the ship-to-air missile for the next shooting in the jth target channel; S43: Repeat step S42 until the movement trajectory of the ship-to-air missile cannot intersect with the anti-ship missile in the kill zone; S44: Determine the engagement situation of shipborne guns based on the combat response time P of the shipborne gun weapon system t and the flight speed V of shipborne gun ammunition p (t), determine the engagement situation of shipborne guns, and draw the flight trajectory diagram of shipborne gun ammunition; if the time from the zero moment to the time when the anti-ship missile reaches the far boundary of the kill zone of the shipborne gun weapon system is greater than the sum of the combat response time P of the shipborne gun weapon system t and the flight time of shipborne gun ammunition, then the shipborne gun ammunition will encounter the anti-ship missile at the far boundary of the kill zone; S45: According to the interval time between two shootings of the shipborne artillery, the flight speed of the shipborne artillery ammunition, and the speed of the anti-ship missile, judge whether the next shipborne artillery ammunition for anti-attack intersects with the anti-ship missile in the kill zone. If it intersects, draw the flight trajectory diagram of the shipborne artillery ammunition for the next anti-attack; S46: Repeat step S45 until the movement trajectory of the shipborne artillery ammunition cannot intersect with the anti-ship missile in the kill zone; Step S5: Analyze and determine the number of times of hard anti-attack of the ship-to-air missile weapon system and the shipborne artillery weapon system against the anti-ship missile according to the graphics drawn in step S4, and calculate the penetration expectation of the anti-ship missile in combination with the kill probability of the ship-to-air missile and the shipborne artillery and the interference probability of the electronic warfare system against the anti-ship missile.
2. The method according to claim 1, characterized in that, in step S1, the target elements include the number of anti-ship missile targets, the interval time between two adjacent single targets in the anti-ship missile, and the velocity vector of the anti-ship missile.
3. The method according to claim 1, characterized in that, in step S2, the technical and tactical indicators of the surface ship's electronic warfare system include: the interference near boundary and far boundary of the electronic warfare system at the flight altitude where the anti-ship missile is located, the horizontal distance at which the early warning and detection system can reliably detect the target, and the interference success rate of the electronic warfare system for each target in the same wave of targets.
4. The method according to claim 1, characterized in that, in step S2, the technical and tactical indicators of the ship-to-air missile weapon system include: the kill zone near boundary and far boundary at the flight altitude where the anti-ship missile is located, the flight velocity vector of the ship-to-air missile, the number of available target channels of the ship-to-air missile weapon system for air incoming targets, the combat reaction time of the ship-to-air missile weapon system, the transfer fire shooting time of the ship-to-air missile weapon system, the interval time between organizing two shootings in two adjacent channels of the ship-to-air missile weapon system, the number of missiles launched each time by the ship-to-air missile weapon system, and the single-shot hit probability of the ship-to-air missile.
5. The method according to claim 1, characterized in that, In step S2, the technical and tactical indicators of the shipborne gun weapon system include: the near boundary and far boundary of the kill zone at the flight altitude of the anti-ship missile, the flight speed vector of the shipborne gun ammunition, the combat reaction time of the shipborne gun weapon system, the interval time between two shots of the shipborne gun weapon system, and the single-shot hit probability of the shipborne gun weapon system.
6. According to the method described in any one of claims 1-5, characterized in that the specific steps of step S3 are: S31: Draw the reliable target detection distance of the detection and warning system; S32: Draw the interference near boundary and far boundary of the electronic warfare system at the flight altitude of the anti-ship missile; S33: Draw the near boundary and far boundary of the kill zone of the ship-to-air missile weapon system at the flight altitude of the anti-ship missile; S34: Draw the near boundary and far boundary of the kill zone of the shipborne gun weapon system at the flight altitude of the anti-ship missile; S35: Calculate the movement trajectories of each anti-ship missile according to the number, interval and speed vector of the anti-ship missiles, and draw the flight trajectory diagram of the anti-ship missiles.
7. According to the method described in any one of claims 1-5, characterized in that the specific steps of step S5 are: S51: Calculate the penetration probability of each anti-ship missile according to the technical and tactical indicators of the electronic warfare system; S52: Calculate the penetration probability of each anti-ship missile according to the technical and tactical indicators and actual combat situation of the ship-to-air missile weapon system; S53: Calculate the penetration probability of each anti-ship missile according to the technical and tactical indicators and actual combat situation of the shipborne gun weapon system; S54: Calculate the penetration expectation of the anti-ship missile stream.
8. According to the method described in claim 1, characterized in that in step S41, the target channel allocation rules are: ① Among the anti-ship missiles in the same wave, those not intercepted by the ship-to-air missile are given priority; ② For those meeting the above conditions, those with a shorter distance between the anti-ship missile and the surface ship are given priority.