Spherical coordinate-based solar ray incidence seeker field-of-view discrimination method

Abstract

The invention relates to the field of military affairs, in particular to a method for discriminating the field of view of a solar ray incidence seeker based on spherical coordinates. According to the method for judging the field of view of the sunlight incident seeker based on the spherical coordinates, the receiving state of the seeker at each position on the trajectory to the sunlight is calculated in a theoretical modeling mode, a theoretical basis and guidance are provided for scheme design of a laser guided weapon combat environment test, and the method is suitable for popularization and application. The method is used for judging whether direct solar light and reflected solar light can enter the seeker of the laser guided weapon or not in a marine environment by judging that the solar light enters the seeker field of view.

Description

Technical Field

[0001] The present invention relates to the military field, and particularly to a method for discriminating the field of view of a seeker into which sunlight enters based on spherical coordinates. Background Art

[0002] A laser-guided bomb is a weapon that uses laser guidance technology to guide the flight trajectory of the bomb, thereby achieving precise target strikes. The high-precision strike ability of laser-guided bombs makes them play an important role in modern warfare.

[0003] It emits a laser beam through a laser target indicator to irradiate the target. The seeker on the bomb captures the laser reflected light, and then calculates and adjusts the flight trajectory according to the deviation of the laser reflected light until the target is hit. Laser-guided bombs have the characteristics of high precision, high efficiency, and low collateral damage rate, and can effectively strike moving, hidden, and fortified targets. However, environmental factors have a greater impact on laser-guided bombs, especially the meteorological environment. Weather conditions such as rain, fog, and snow will interfere with the propagation of the laser, reducing the guidance accuracy of laser-guided bombs. The interference of the weather may even generate false targets, causing the laser-guided bomb to be deflected, seriously affecting the normal use of laser-guided bombs.

[0004] In addition, the seeker is highly sensitive to sunlight. For weapons equipped with optical seekers, it has been taken into account in the design stage in terms of ballistic and weapon attitude changes, so as to avoid the "malfunction" of the seeker caused by direct sunlight during use. However, in the marine environment, in addition to direct sunlight, there is also reflection on the sea surface, i.e., fish-scale light, in the way sunlight enters the seeker. After the reflected light enters the seeker, it will cause the same effect as direct sunlight. Therefore, judging whether sunlight can be reflected into the seeker in the marine environment during the use of laser-guided weapons is an important prerequisite for ensuring the delivery accuracy of laser-guided weapons. Summary of the Invention

[0005] The present invention discloses a method for discriminating the field of view of a seeker into which sunlight enters based on spherical coordinates. By means of theoretical modeling, the reception state of the seeker for sunlight at each position on the ballistic trajectory is calculated, providing a theoretical basis and guidance for the design of the combat environment test plan of laser-guided weapons.

[0006] The present invention provides a method for discriminating the field of view of a seeker into which sunlight enters based on spherical coordinates, including the following steps:

[0007] Step 1: Obtain the ballistic data of the laser-guided bomb;

[0008] Step 2: Solve the field-of-view attitude of the seeker of the laser-guided bomb;

[0009] Step 3: Establish the relative relationship between the seeker of the laser-guided bomb and the sun's rays;

[0010] Step 4: Obtain the conditions for determining that the sun's rays enter the seeker's field of view.

[0011] According to the discrimination method for the sun's rays entering the seeker's field of view based on spherical coordinates provided by the present invention, the ballistic data of the laser-guided bomb in Step 1 includes the attitude angle of the laser-guided bomb, the position coordinates of the laser-guided bomb, the elevation angle of the seeker frame, and the pitch angle of the seeker frame.

[0012] According to the discrimination method for the sun's rays entering the seeker's field of view based on spherical coordinates provided by the present invention, the seeker field-of-view attitude of the laser-guided bomb in Step 2 includes the elevation angle ρ g of the seeker and the azimuth angle ρ f of the seeker.

[0013] According to the discrimination method for the sun's rays entering the seeker's field of view based on spherical coordinates provided by the present invention, the method for establishing the relative relationship between the seeker of the laser-guided bomb and the sun's rays in Step 3 is to establish a spherical coordinate system at the head of the laser-guided bomb, and calculate the angle between the central axis of the laser-guided bomb and the direct sunlight line and the angle between the central axis of the laser-guided bomb and the direct reflected sunlight line.

[0014] According to the discrimination method for the sun's rays entering the seeker's field of view based on spherical coordinates provided by the present invention, the angle between the central axis of the laser-guided bomb and the direct sunlight line is:

[0015]

[0016] In the formula, θ s is the solar altitude angle, θ t is the elevation angle ρ g of the seeker, is the solar azimuth, is the geographic azimuth angle of the seeker of the laser-guided bomb.

[0017] According to the discrimination method for the sun's rays entering the seeker's field of view based on spherical coordinates provided by the present invention, the angle between the central axis of the laser-guided bomb and the direct reflected sunlight line is:

[0018]

[0019] According to the discrimination method for the sun's rays entering the seeker's field of view based on spherical coordinates provided by the present invention, the condition for determining that the sun's rays enter the seeker's field of view in Step 4 is: ɑ > ∠tos1 ∨ ɑ > ∠tos2,

[0020] In the formula, α is the field of view angle of the seeker of the laser-guided bomb, ∠tos1 is the angle between the central axis of the laser-guided bomb and the direct sunlight irradiation line, and ∠tos2 is the angle between the central axis of the laser-guided bomb and the direct sunlight reflection line.

[0021] The present invention has the following advantages compared with the prior art:

[0022] The discrimination method of the incident sunlight field of view of the seeker based on spherical coordinates provided by the present invention calculates the reception state of the sunlight by the seeker at each position on the ballistic through theoretical modeling, provides a theoretical basis and guidance for the scheme design of the combat environment test of laser-guided weapons, and discriminates whether the direct sunlight and the reflected sunlight can enter the seeker of the laser-guided weapon by discriminating the incident sunlight field of view of the seeker. Description of the Drawings

[0023] Figure 1 It is the relative relationship between the seeker and the projectile body;

[0024] Figure 2 It is the situation diagram of the laser-guided bomb during flight and sunlight;

[0025] Figure 3 It is a schematic diagram of the spherical coordinate system of the head of the laser-guided bomb;

[0026] Figure 4 It is a schematic diagram of the ballistic entry direction;

[0027] Figure 5 It is a schematic diagram of the auxiliary line of the spherical coordinate system. Detailed Embodiment

[0028] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention.

[0029] The following combines Figures 1 - 5 The embodiments shown to describe the technical solutions of the present invention:

[0030] The present invention provides a discrimination method for the incident sunlight field of view of the seeker based on spherical coordinates. The specific steps of the method are as follows;

[0031] Step 1: Obtain the ballistic data of the laser-guided bomb;

[0032] The acquisition of ballistic data can be achieved by means of the simulation program corresponding to the missile type or the data information obtained through telemetry. The types of data should include the attitude angles (pitch angle, yaw angle, and roll angle) of the laser-guided bomb, the position coordinates of the laser-guided bomb, and for the seeker missile type with a frame, the elevation angle of the seeker frame and the pitch angle of the seeker frame also need to be obtained.

[0033] Step 2: Solve the attitude of the seeker field of view of the laser-guided bomb;

[0034] The seeker of the laser-guided bomb and the missile body are mechanically connected to jointly form the laser-guided bomb. During the combat use of the laser-guided bomb, the seeker determines the relative relationship between the missile and the target by capturing the position of the spot illuminated by the optoelectronic pod, so as to guide the laser-guided bomb to attack the target. Therefore, from a mechanical perspective, a two-rigid-body system is formed between the seeker and the missile body. The problem of the seeker pointing needs to establish a translation coordinate system based on the current position of the laser-guided bomb, and determine its pointing according to the characteristics of different types of seekers. Let the ground coordinate system where the seeker of the laser-guided bomb is located be denoted as O xyz , where O x is the due north direction, O z is the due east direction, O y is the sky direction, and L is the unit vector of the seeker pointing.

[0035] When the seeker adopted by the laser-guided bomb is a vane seeker, its pointing is consistent with the missile body velocity direction. Therefore, the angles determining its azimuth are the ballistic inclination angle ψ v and the ballistic deflection angle θ 1b .

[0036] Considering the laser-guided bomb with precision guidance, its ballistic plane is basically in the vertical plane. The calculation formulas for its ballistic inclination angle and ballistic deflection angle can be obtained by using a simplified calculation method:

[0037] ψ v = ψ - β(1)

[0038]

[0039] where is the pitch angle of the bomb, ψ is the yaw angle of the bomb, α is the angle of attack of the bomb, and β is the sideslip angle of the bomb.

[0040] When the seeker adopted by the laser-guided bomb is not a vane seeker, for most laser-guided bombs, the seeker is located inside the frame connected to the missile body. There is a coordinate conversion relationship between the seeker and the missile body, which needs to be obtained according to the matrix relationship:

[0041]

[0042] where

[0043]

[0044] Among them, k jgd and k jfw respectively represent the elevation angle of the seeker frame of the GGG laser-guided bomb and the pitch angle of the seeker frame. γ is the roll angle of the laser-guided bomb. Then, according to the above matrix multiplication relationship, the elevation angle of the seeker and the azimuth angle of the seeker can be expressed as:

[0045]

[0046] Let the attitude angle of the seeker's field of view be ρ g and ρ f , where ρ g is the elevation angle of the seeker, and ρ f is the azimuth angle of the seeker. Then it can be expressed as:

[0047]

[0048] Step 3: Establish the relative relationship between the seeker of the laser-guided bomb and the sun rays;

[0049] The situation of the laser-guided bomb during flight with respect to the sun is as Figure 2 shown.

[0050] Among them:

[0051] The central axis of the laser-guided bomb is ot, and the projection of the central axis ot on the horizontal plane is ot'. The elevation angle ρ g of the seeker of the laser-guided bomb = ∠tot', that is, the field of view angle of the seeker of the laser-guided bomb is ∠tot1, denoted as α;

[0052] The sun ray s1o directly irradiates the inside of the seeker of the laser-guided bomb, and the reflected ray s2o of the sun ray s3s2 enters the inside of the seeker after being reflected by the water surface mirror. The solar altitude angle is ∠s'os1.

[0053] The included angle between the vertical plane where the central axis of the laser-guided bomb is located and the vertical plane where the sun ray entering the seeker is located is ∠t'os'.

[0054] When the sun ray s1o or the reflected ray s2o after reflection by the water surface enters the field of view of the seeker of the laser-guided bomb, that is, ∠tos1 < ∠tot1 or ∠tos2 < ∠tot1, the seeker of the laser-guided bomb will be blinded and malfunction. For the convenience of calculating ∠tos1 and ∠tos2, a spherical coordinate system is established at the head of the laser-guided bomb, as Figure 3 shown.

[0055] In the spherical coordinate system, for clarity: θ t = ρ g = ∠tot' is the elevation angle of the seeker of the laser-guided bomb, θs is the solar altitude angle, is the geographic azimuth of the laser-guided bomb seeker, and the relationship between it and the seeker azimuth can be expressed as Where π is the angle between the projection vector of the trajectory on the ground and the true north direction, which is called the trajectory entry azimuth, such as Figure 4 As shown, The sun position.

[0056] Therefore, the relationship between the laser-guided bomb posture and the sun's rays can be expressed using spherical coordinates: the direction of the central axis of the laser-guided bomb can be expressed as The direction of the direct sunlight ray os1 can be expressed as The direction of the sunlight reflected ray os2 can be expressed as

[0057] For the convenience of calculation, a line perpendicular to the equatorial plane intersecting the equatorial plane at t is made for point t on the central axis of the laser-guided bomb and point s2 on the sun's reflected light. o and o Two points, and then from point s2 to the straight line t o Draw a perpendicular line through t and intersect it at point t1.

[0058] Assume that the radius of the sphere is R, at a right angle △ott o and right angle △os2s o There are:

[0059]

[0060] In △ot o s o and △ots2 have:

[0061]

[0062] In the plane o s o In s2, there are:

[0063] s2t 2 =t1t 2 +t1s2 2 (15)

[0064] In the plane o s o In s2, there are:

[0065]

[0066] Combining the above formulas (13), (14), (15) and (16), we get:

[0067]

[0068] Therefore, the included angle between the central axis ot of the laser-guided bomb and the direct sunlight irradiation line os1 is:

[0069]

[0070] Similarly, it can be obtained that the included angle between the central axis ot of the laser-guided bomb and the reflected sunlight irradiation line os2 is:

[0071]

[0072] Step 4: Obtain the condition for determining that the sun ray enters the seeker's field of view;

[0073] When both direct and reflected sunlight will affect the laser-guided bomb, the seeker will be affected by the sun ray and should meet the following conditions:

[0074] ɑ > ∠tos1 ∨ ɑ > ∠tos2 (20)

[0075] The discrimination method for the sun ray incident on the seeker's field of view based on spherical coordinates provided by the present invention calculates the receiving state of the sun ray by the seeker at each position on the ballistic trajectory through theoretical modeling, provides a theoretical basis and guidance for the design of the laser-guided weapon combat environment test plan, and is used to determine whether the direct sunlight and the reflected sunlight can enter the inside of the laser-guided weapon seeker in the marine environment by discriminating the sun ray incident on the seeker's field of view.

[0076] The above is only a preferred embodiment of this example and does not impose any limitation on this example. Any simple modification, change, and equivalent change made to the above example according to the technical essence of the invention still fall within the protection scope of the technical solution of this example.

Claims

1. A discriminant method for the incident solar rays on the seeker field of view based on spherical coordinates, characterized in that, It includes the following steps: Step 1: Obtain the ballistic data of the laser-guided bomb; Step 2: Solve the attitude of the laser-guided bomb seeker's field of view; Step 3: Establish the relative relationship between the laser-guided bomb seeker and the sun's rays; Step 4: Obtain the conditions for determining that the sun's rays enter the seeker's field of view.

2. A discrimination method for the field of view of a solar ray incident seeker based on spherical coordinates as described in claim 1, characterized in that, The ballistic data of the laser-guided bomb described in Step 1 includes the attitude angle of the laser-guided bomb, the position coordinates of the laser-guided bomb, the elevation angle of the seeker frame, and the pitch angle of the seeker frame.

3. A discrimination method for the field of view of a solar ray incident seeker with spherical coordinates as described in claim 2, characterized in that, The field-of-view attitude of the laser-guided bomb seeker described in step 2 includes the elevation angle ρ of the seeker g and the azimuth angle ρ of the seeker f .

4. A discrimination method for the field of view of a solar ray incident seeker in spherical coordinates as described in claim 1, characterized in that, The method for establishing the relative relationship between the laser-guided bomb seeker and the sun's rays described in Step 3 is to establish a spherical coordinate system at the head of the laser-guided bomb, and calculate the angle between the central axis of the laser-guided bomb and the direct irradiation line of the sun's rays and the angle between the central axis of the laser-guided bomb and the direct reflection line of the sun's rays.

5. A discriminant method for the field of view of a solar ray incident seeker in spherical coordinates as described in claim 4, characterized in that, The angle between the central axis of the laser-guided bomb and the direct irradiation line of the sun's rays is: In the formula, θ s is the solar altitude angle, θ t is the elevation angle of the seeker, ρ g , is the solar azimuth, is the geographical azimuth angle of the seeker of the laser-guided bomb.

6. A discriminant method for the field of view of a solar ray incident seeker in spherical coordinates as described in claim 5, characterized in that, The angle between the central axis of the laser-guided bomb and the direct reflection line of the sun's rays is:

7. A discriminant method for the field of view of a solar ray incident seeker with spherical coordinates as described in claim 5, characterized in that, The conditions for determining that the sun's rays enter the seeker's field of view described in Step 4 are: α>∠tos1∨α>∠tos2, where α is the field of view angle of the laser-guided bomb seeker, ∠tos1 is the angle between the central axis of the laser-guided bomb and the direct irradiation line of the sun's rays, and ∠tos2 is the angle between the central axis of the laser-guided bomb and the direct reflection line of the sun's rays.

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