Position limiting algorithm for dynamic directivity symbols based on relative offset

Abstract

The position limiting algorithm for the dynamic directional symbols based on the relative offset comprises the steps that the display range of the dynamic directional symbols on a display interface is determined, and the dynamic directional symbols comprise point type symbols and line type symbols; determining a first display position and a first relative offset after the position of the dynamic directivity point class symbol is limited; determining a second display position and a second relative offset after the position of the dynamic directional line symbol is limited; and according to the first display position and the display position of the first relative offset control point type symbol in the picture, and according to the second display position and the display position of the second relative offset control point type symbol in the picture, the problem that the dynamic directional symbol cannot be observed after exceeding the display range is effectively solved.

Description

Technical Field

[0001] The invention belongs to the field of aiming display technology and relates to a position limiting algorithm of a dynamic directional symbol based on relative offset. Background Art

[0002] The dynamic directional symbols used in the aiming display system are mostly navigation, target tracking, aiming or attack symbols. Their rotation angle is the roll angle of the carrier aircraft, and the reference symbol is the flight path marker (FPM), climb / dive marker (CDM) or the center point of the field of view.

[0003] For aiming display systems, there are two types of FOV, namely the instantaneous field of view (IFOV) and the total field of view (TFOV). The instantaneous field of view is the maximum field of view that the user can observe without moving the head when designing the eye position; the total field of view is the total convergence angle of the image light that can be observed when the eye position moves. Generally speaking, the instantaneous field of view is smaller than the total field of view.

[0004] Different dynamic directional symbols have different corresponding display ranges due to their different functions. For example, some symbols need to be displayed within the instantaneous field of view, some symbols need to be displayed within the field of view expanded 1 degree outside the instantaneous field of view, and some symbols need to be displayed within the total field of view. When the position of a dynamic directional symbol exceeds the corresponding display range, the user will not be able to observe the dynamic directional symbol, and thus will not be able to effectively guide airborne sensors and weapons to search, identify, track, aim or attack. Therefore, it is necessary to restrict the position of dynamic directional symbols that exceed the corresponding display range to facilitate user observation. Summary of the invention

[0005] In view of this, the position limitation algorithm of dynamic directional symbols based on relative offset provided by the present invention fully considers the position limitation requirements of point and line dynamic directional symbols, and provides corresponding position limitation algorithms respectively, which can effectively solve the problem that dynamic directional symbols cannot be observed after exceeding their display range.

[0006] A position limiting algorithm for a dynamic directional symbol based on relative offset, the position limiting algorithm comprising the following steps:

[0007] Step 1: Determine the display range of the dynamic directional symbols on the display interface, the dynamic directional symbols include point symbols and line symbols;

[0008] Step 2: Calculate the theoretical display position according to the characteristics of the point symbol, and use the first preset method and the second preset method for processing when it is a preset angle. When it is a non-preset angle, determine the first display position and the first relative offset of the dynamic directional point symbol after the position restriction by judging the slope range of the connecting line between the reference symbol and the point symbol;

[0009] Step 3: Calculate the vertical point from the reference symbol to the line symbol according to the characteristics of the line symbol. When the angle is preset, use the third preset method or the fourth preset method for processing. When the angle is not preset, determine the expressions of four straight lines that pass through the four vertices of the display range and are parallel to the line symbol. Determine the second display position and the second relative offset after the position of the dynamic directional line symbol is restricted by judging the positive or negative sign of the relative offset and using the distance from the reference symbol to the four straight lines.

[0010] Step 4: Control the display position of the point symbol in the picture according to the first display position and the first relative offset, and control the display position of the line symbol in the picture according to the second display position and the second relative offset.

[0011] The technical beneficial effects of the present invention are:

[0012] First, the definition and display range of dynamic directional symbols are clarified, and dynamic directional symbols are divided into two categories, point symbols and line symbols; secondly, according to the characteristics of point symbols, the theoretical display position is calculated first, and then the processing at the preset angle is considered. Finally, for non-preset angles, the first display position and the first relative offset of the dynamic directional point symbol after position restriction are determined by judging the slope range of the connecting line between the reference symbol and the point symbol; thirdly, according to the characteristics of line symbols, the vertical point from the reference symbol to the line symbol is calculated first, and then the processing at the preset angle is considered. Finally, for non-preset angles, the expressions of four straight lines passing through the four vertices of the display range and parallel to the line symbol are determined, and the second display position and the second relative offset of the dynamic directional line symbol after position restriction are determined by judging the positive and negative relative offset and using the distance from the reference symbol to the four straight lines; finally, the display position of the point symbol in the picture is controlled according to the first display position and the first relative offset, and the display position of the line symbol in the picture is controlled according to the second display position and the second relative offset. This method fully considers the position restriction requirements of point and line dynamic directional symbols, and gives corresponding position restriction algorithms respectively, which can effectively solve the problem that dynamic directional symbols cannot be observed after exceeding their display range. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0014] Figure 1 It is a schematic diagram of the restriction of the position of the point-type dynamic directional symbol;

[0015] Figure 2 It is a schematic diagram of the limitation of the point-type dynamic directional symbol at the preset angle position;

[0016] Figure 3 A schematic diagram showing the restrictions on the position of line-type dynamic directional symbols. DETAILED DESCRIPTION

[0017] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0018] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present disclosure.

[0019] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0020] Basic Concepts of Dynamic Directional Symbols

[0021] A dynamic directional symbol refers to a dynamic symbol that rotates around a reference symbol and has a certain position offset relative to the reference symbol. Depending on the factors that need to be considered when performing position restrictions, dynamic directional symbols are divided into point symbols and line symbols. Point symbols refer to symbols that only need to consider the symbol reference point when performing position restrictions, and do not need to consider the size of the symbol itself. Such symbols are generally small in size. Line symbols refer to symbols that not only need to consider the symbol reference point but also the size of the symbol itself when performing position restrictions. Such symbols are generally large in size and mostly linear. The display range corresponding to a certain dynamic directional symbol can be a variety of styles such as rectangles and circles. The present invention only uses two rectangular ranges of W degrees in azimuth and H degrees in pitch, and WB degrees in azimuth and HB degrees in pitch as examples for explanation, and the display range of the dynamic directional symbol must be greater than or equal to the display range of its reference symbol.

[0022] like Figures 1 to 3 The position limiting algorithm of the dynamic directional symbol based on relative offset shown in the figure comprises the following steps:

[0023] Step 1: Determine the display range of the dynamic directional symbols on the display interface, the dynamic directional symbols include point symbols and line symbols;

[0024] Step 2: Calculate the theoretical display position according to the characteristics of the point symbol, and use the first preset method and the second preset method to process when the angle is a preset angle (0 degree, ±90 degrees, ±180 degrees). When the angle is not a preset angle, determine the first display position and the first relative offset of the dynamic directional point symbol after the position is restricted by judging the slope range of the connecting line between the reference symbol and the point symbol.

[0025] Step 3: Calculate the vertical point from the reference symbol to the line symbol according to the characteristics of the line symbol. When the angle is preset, use the third preset method or the fourth preset method for processing. When the angle is not preset, determine the expressions of four straight lines that pass through the four vertices of the display range and are parallel to the line symbol. Determine the second display position and the second relative offset after the position of the dynamic directional line symbol is restricted by judging the positive or negative sign of the relative offset and using the distance from the reference symbol to the four straight lines.

[0026] Step 4: Control the display position of the point-type symbol in the screen according to the first display position and the first relative offset, and control the display position of the line-type symbol in the screen according to the second display position and the second relative offset. For example, draw a line-type dynamic directional symbol through OpenGL according to the second display position and the second relative offset position, and display it, thereby guiding the airborne sensor to search, identify and track.

[0027] Considering different dynamic directional symbols, due to the different functions of the symbols, the corresponding display ranges are different. When the position of a dynamic directional symbol exceeds the corresponding display range, the user will not be able to observe the dynamic directional symbol, so it is necessary to restrict the position of the dynamic directional symbol that exceeds the corresponding display range. Before applying the position restriction algorithm, it is necessary to first confirm which category of dynamic directional symbol it belongs to and determine its corresponding display range boundary, and then select the corresponding position restriction algorithm according to the symbol category, and process the display position after restriction and the relative offset after restriction to control the display position of the symbol in the picture.

[0028] As a specific implementation method provided in this case, a dynamic directional symbol is a dynamic symbol that rotates around a reference symbol and has a position offset relative to the reference symbol, and a point symbol is a symbol that only needs to consider the symbol reference point when performing position restrictions, and does not need to consider the size of the symbol itself; this type of symbol is generally small in size. A line symbol is a symbol that needs to consider the symbol reference point and the size of the symbol itself when performing position restrictions. This type of symbol is generally large in size and is mostly linear.

[0029] As a specific implementation method provided in this case, the first display position and the first relative offset after the position restriction of the dynamic directional point symbol are determined; the second display position and the second relative offset after the position restriction of the dynamic directional line symbol are determined. Because the first relative offset and the second relative offset are directional, they are positive and negative, and the positive and negative of the relative offset after the position restriction are the same as the positive and negative of the relative offset in the initial state.

[0030] As a specific implementation method provided in this case, when the angle is not preset, the slope range of the connecting line between the reference symbol and the point symbol is determined by judging that the connecting line of the point-type dynamic directional symbol is a connecting line between the reference point of the reference symbol and the reference point of the point-type dynamic directional symbol, and the slope of the connecting line of the non-preset angle is determined, wherein,

[0031] The slope of the connecting line without preset angle is recorded as slope FD0slope. Assuming that the rotation angle is 0 degrees at 12 o'clock and increases counterclockwise, we can get:

[0032] FD0slope=tan(roll+90), where roll is a non-preset angle.

[0033] Furthermore, when a certain point-type dynamic directional symbol exceeds its corresponding display range, after the position restriction, the intersection of the connecting line of the point-type dynamic directional symbol and the boundary of its corresponding display range is used as the first display position of the point-type dynamic directional symbol after the position restriction, and then the first relative offset is obtained, including,

[0034] Determination of the first display position and the first relative offset

[0035] Get the reference point F of the reference symbol with coordinates (fx, fy), get the display range corresponding to the dynamic directional symbol as a rectangular range of W degrees in azimuth and H degrees in elevation, get the relative offset of the point-type dynamic directional symbol as Originalshift, the relative offset is a non-zero value, and in the following processing, assume that the relative offset is positive at the top and negative at the bottom. First calculate the theoretical display position D0 (D0x, D0y) of the point-type dynamic directional symbol, and then determine whether D0 exceeds the display range. If so, limit the position of D0 to obtain the first display position D1 (D1x, D1y) of the point-type symbol after the limit and its corresponding first relative offset Limitshift after the position limit, where:

[0036] Calculate the theoretical display position D0, D0x = fx – Originalshift*sin(roll);

[0037] D0y=fy+Originalshift*cos(roll);

[0038] Determine whether D0 exceeds the display range. If the azimuth direction is within the range of [-W / 2, W / 2], and the elevation direction is within the range of [-H / 2, H / 2], it does not exceed the display range, and D0 is the first display position D1 of the point symbol, and Originalshift is the first relative offset Limitshift. Otherwise, position restriction is performed.

[0039] Since the slope of the straight line FD0 is required in the position limitation process, the preset angle is processed as follows:

[0040] When roll is ±90 degrees, the straight line FD0 is parallel to the X axis. Since the display range of the dynamic directivity symbol must be greater than or equal to the display range of its reference symbol, fy does not exceed the limit, and then D0y does not exceed the limit, so D0x exceeds the limit. The first preset method (according to the following three formulas) is used to calculate the first display position D1 and the first relative offset Limitshift after the position limit, where sign(X) is -1 when X is negative, otherwise it is 1, where,

[0041] D1x=W / 2*sign(D0x);

[0042] D1y=fy;

[0043] Limitshift=(W / 2–sign(D0x)*fx)*sign(Originalshift);

[0044] When roll is 0 degrees and ±180 degrees, the straight line FD0 is parallel to the Y axis. Since fx does not exceed the limit, D0x does not exceed the limit, so D0y exceeds the limit. The second preset method (according to the following three formulas) is used to calculate the first display position D1 and the first relative offset Limitshift after the position limit, where:

[0045] D1x=fx;

[0046] D1y=H / 2*sign(D0y);

[0047] Limitshift=(H / 2–sign(D0y)*fy)*sign(Originalshift)

[0048] If roll is not a preset angle, the process is as follows:

[0049] Obtain the constant FD0b in the expression Y=FD0slope*X+FD0b for the straight line FD0.

[0050] FD0b = fy - FD0slope * fx;

[0051] Get the positions of the four vertices in the display range, and calculate the slopes of the lines connecting the reference symbol reference point F and the four vertices E, G, K, and H, which are expressed as FEslope, FGslope, FKslope, and FHslope respectively;

[0052] If D0x is greater than or equal to fx, that is, D0 is on the right side of F, and if FD0slope is within the range of [FHslope, FGslope], then the intersection of the straight line FD0 and the right boundary is calculated; if FD0slope is less than FHslope, then the intersection of the straight line FD0 and the lower boundary is calculated; if FD0slope is greater than FGslope, then the intersection of the straight line FD0 and the upper boundary is calculated;

[0053] If D0x is less than fx, that is, D0 is on the left side of F: if FD0slope is within the range of [FEslope, FKslope], then calculate the intersection of the straight line FD0 and the left boundary; if FD0slope is less than FEslope, then calculate the intersection of the straight line FD0 and the upper boundary; if FD0slope is greater than FKslope, then calculate the intersection of the straight line FD0 and the lower boundary;

[0054] The first display position D1 of the point symbol after position restriction is determined according to the intersection point. Since the position F is known, the distance FD1 can be obtained, and then the first relative offset Limitshift of the point symbol after restriction can also be calculated, which is expressed as Limitshift=FD1*sign(Originalshift).

[0055] Further, determining the second display position and the second relative offset of the dynamic directional line symbol after the position restriction includes: the vertical point from the reference symbol to the line dynamic directional symbol, which means drawing a vertical line from the reference point of the reference symbol to the line dynamic directional symbol, and the intersection of the vertical line and the line dynamic directional symbol is taken as the vertical point, and the vertical point is the reference point of the line dynamic directional symbol; specifically, in step three, the second display position of the line dynamic directional symbol after the position restriction will be located within the quadrilateral range surrounded by four straight lines passing through the four vertices of its display range and parallel to the line symbol, and the second relative offset after the position restriction will not be greater than the distance from the reference symbol to the four straight lines passing through the four vertices of the display range and parallel to the line symbol, wherein the second display position and the second relative offset are determined as follows:

[0056] Get the reference point F2 of the reference symbol and the coordinates are (f2x, f2y), get the display range corresponding to the line symbol as a rectangular range of WB degrees in the azimuth direction and HB degrees in the pitch direction, get the initial relative offset of the line dynamic directivity symbol as Originalshift2, the relative offset is a non-zero value (in the following processing, assume that the relative offset is positive on the right and negative on the left), get the rotation angle of the line symbol relative to the reference symbol as roll2, assume that the rotation angle is 0 degrees at 12 o'clock and increases counterclockwise, including,

[0057] Determine the display position F2 of the reference symbol to the vertical point position D of the line symbol;

[0058] Dx=f2x+Originalshift2*cos(roll2);

[0059] Dy=f2y+Originalshift2*sin(roll2);

[0060] Determine whether D exceeds the display range. If the azimuth direction is within the range of [-WB / 2, WB / 2] and the elevation direction is within the range of [-HB / 2, HB / 2], it does not exceed the display range, D is the second display position D2, and Originalshift2 is the second relative offset Limitshift2; otherwise, position restriction is required;

[0061] Since the slope of the line where the line symbol is located is required in the position restriction process, the preset angle is processed as follows:

[0062] If roll2 is ±90 degrees, the straight line F2D is parallel to the Y axis. Since the display range of the dynamic directional symbol must be greater than or equal to the display range of its reference symbol, f2x does not exceed the limit, so Dx does not exceed the limit, and therefore Dy exceeds the limit. The third preset method (the following three formulas) is used to calculate the second display position and the second relative offset after the position limit, where sign(X) is -1 when X is negative, otherwise it is 1.

[0063] D2x=f2x+Originalshift2*sign(Dx);

[0064] D2y=f2y;

[0065] Limitshift2=(HB / 2–sign(Dy)*f2y)*sign(Originalshift2);

[0066] If roll2 is 0 degrees or ±180 degrees, the straight line F2D is parallel to the X axis. Since f2y does not exceed the boundary, Dy does not exceed the boundary either, so Dx exceeds the boundary. The fourth preset method (the following three formulas) is used to calculate the second display position after position restriction and the second relative offset:

[0067] D2x=f2x;

[0068] D2y=f2y+Originalshift2*sign(Dy);

[0069] Limitshift2=(WB / 2-sign(Dx)*f2x)*sign(Originalshift2);

[0070] If roll is not a preset angle, the process is as follows:

[0071] Assuming that the line where the line symbol is located is line BD, then line BD is perpendicular to line F2D. Therefore, according to the rotation angle, the slope of line BD can be obtained as BDslope = tan(roll+90).

[0072] Based on the coordinates of the four vertices E2, G2, K2, and H2 of the display range and BDslope, the expression of BDslope*X+b[i]=Y for the four straight lines (i.e., limit lines) passing through the four vertices and parallel to the straight line BD is obtained, which is expressed as follows:

[0073] Upper right vertex G2: b[0] = HB / 2-WB / 2*BDslope

[0074] Lower left vertex K2: b[1] = -HB / 2 + WB / 2 * BDslope

[0075] Upper left vertex E2: b[2] = HB / 2 + WB / 2 * BDslope

[0076] Lower right vertex H2: b[3] = -HB / 2-WB / 2*BDslope

[0077] Calculate the distance Len[i] from position F2 to the four limit lines, expressed as follows,

[0078]

[0079] If Originalshift2 is greater than 0, the second relative shift is limited according to roll2:

[0080] When roll2 is in the range of (0, 90), the line symbol can go as far as the position passing through the upper right vertex G2 (corresponding to Len[0]) (the slope is still BDslope);

[0081] When roll2 is within the range of (90, 180), the line symbol can reach as far as the position passing through the upper left vertex E2 (corresponding to Len[2]) (the slope is still BDslope);

[0082] When roll2 is within the range of (-90, 0), the line symbol can reach as far as the position passing through the lower right vertex H2 (corresponding to Len[3]) (the slope is still BDslope);

[0083] When roll2 is within the range of (-180, -90), the line symbol can reach as far as the position passing through the lower left vertex K2 (corresponding to Len[1]) (the slope is still BDslope);

[0084] Use the numerical limit operation Out = LIMIT (In, Min, Max), where the operation input is the data In, the limit lower boundary Min and the limit upper boundary Max, and the operation output is the data Out: when In is greater than Max, the operation output is Max; when In is less than Min, the operation output is Min; when In is within the range of [Min, Max], the operation output is In; according to the judgment result of roll2, combined with the numerical limit operation, the second relative offset Limitshift2 after position limitation is calculated, which is expressed as,

[0085] Second relative shift Limitshift2 = LIMIT (Originalshift2, 0, len[i]);

[0086] If the second relative shift Originalshift2 is less than 0, the relative shift is limited according to roll2:

[0087] When roll2 is in the range of (0, 90), the line symbol can reach as far as the position passing through the lower left vertex K2 (corresponding to Len[1]) (the slope is still BDslope);

[0088] When roll2 is within the range of (90, 180), the line symbol can reach as far as the position passing through the lower right vertex H2 (corresponding to Len[3]) (the slope is still BDslope);

[0089] When roll2 is within the range of (-90, 0), the line symbol can reach as far as the position passing through the upper left vertex E2 (corresponding to Len[2]) (the slope is still BDslope);

[0090] When roll2 is within the range of (-180, -90), the line symbol can reach as far as the position passing through the upper right vertex G2 (corresponding to Len[0]) (the slope is still BDslope);

[0091] According to the judgment result of roll2, combined with the numerical limit operation, the second relative offset after position limitation is calculated, which is expressed as Limitshift2=LIMIT(Originalshift2,-len[i],0);

[0092] According to the display position F2 of the reference symbol and the second relative offset Limitshift2, the second display position D2 of the restricted line symbol can be obtained.

[0093] D2x=f2x+Limitshift2*cos(roll2)

[0094] D2y=f2y+Limitshift2*sin(roll2).

[0095] Before applying the position restriction algorithm, it is necessary to first clarify whether it is a dynamic directional symbol; if so, it is necessary to further clarify which category of dynamic directional symbols it belongs to, and determine its corresponding display range boundary; then select the corresponding position restriction algorithm according to the category, and process to obtain the Nth display position of the dynamic directional symbol after the position restriction and the Nth relative offset of the dynamic directional symbol after the position restriction (N is one or two). For an aiming display system that relies on the specific position of the symbol for drawing, the display position of the dynamic directional symbol in the picture can be determined according to the Nth display position of the dynamic directional symbol, and then drawn; for an aiming display system that relies on the relative relationship of the symbol for drawing, the display position of the dynamic directional symbol in the picture can be determined according to the position of the reference symbol, the rotation angle and the Nth relative offset of the dynamic directional symbol, and then drawn. The present invention fully considers the position restriction requirements of point-type and line-type dynamic directional symbols, and provides corresponding position restriction algorithms respectively, which can effectively solve the problem that the dynamic directional symbol cannot be observed after exceeding its display range.

[0096] The above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A position restriction algorithm for dynamic directional symbols based on relative offset, characterized in that: The position restriction algorithm comprises the following steps: Step 1: Determine the display range of the dynamic directional symbols on the display interface, the dynamic directional symbols include point symbols and line symbols; Step 2: Calculate the theoretical display position according to the characteristics of the point symbol, and use the first preset method and the second preset method to process when it is a preset angle, and determine the first display position and the first relative offset of the dynamic directional point symbol after the position restriction by judging the slope range of the connecting line between the reference symbol and the point symbol when it is a non-preset angle; Step three: Calculate the vertical point from the reference symbol to the line symbol according to the characteristics of the line symbol, and use the third preset method and the fourth preset method for processing when it is a preset angle, and determine the expressions of four straight lines passing through the four vertices of the display range and parallel to the line symbol when it is a non-preset angle, and determine the second display position and the second relative offset of the dynamic directional line symbol after the position restriction by judging the positive and negative nature of the relative offset and using the distance from the reference symbol to the four straight lines; Step 4: Control the display position of the point symbol in the picture according to the first display position and the first relative offset, and control the display position of the line symbol in the picture according to the second display position and the second relative offset.

2. The position restriction algorithm according to claim 1, characterized in that ,The dynamic directional symbol is a dynamic symbol that rotates around a reference symbol and has a position offset relative to the reference symbol.

3. The position restriction algorithm according to claim 2, characterized in that: The point symbol is a symbol that only needs to consider the symbol reference point when performing position restrictions, and does not need to consider the symbol's own size; the line symbol is a symbol that needs to consider the symbol reference point and the symbol's own size when performing position restrictions.

4. The position restriction algorithm according to claim 1, characterized in that , the preset angles are 0 degree, ±90 degrees, and ±180 degrees.

5. The position restriction algorithm according to claim 3 is characterized in that ,determine the first display position and the first relative offset of the dynamic directional point symbol after position restriction; Determine the second display position and the second relative offset after the dynamic directional line symbol position is limited. Since the first relative offset and the second relative offset are directional, they are positive and negative, and the positive and negative of the relative offset after the position limitation are the same as those of the relative offset in the initial state.

6. The position restriction algorithm according to claim 5, characterized in that When the angle is not set, the slope of the connecting line between the reference symbol and the point symbol is determined by judging that the connecting line of the point-type dynamic directional symbol is a connecting line between the reference point of the reference symbol and the reference point of the point-type dynamic directional symbol, and the slope of the connecting line of the non-set angle is determined, wherein, The slope of the connecting line without a preset angle is recorded as slope FD0slope, which can be obtained FD0slope=tan(roll+90), rol l is a non-preset angle.

7. The position restriction algorithm according to claim 6, characterized in that: When a point-type dynamic directional symbol exceeds its corresponding display range, after position restriction, the intersection of the connecting line of the point-type dynamic directional symbol and the boundary of its corresponding display range is used as the first display position of the point-type dynamic directional symbol after position restriction, and then the first relative offset is obtained, including: The reference point F of the reference symbol is obtained, and the coordinates are (fx, fy); the display range corresponding to the dynamic directional symbol is obtained as a rectangular range of W degrees in the azimuth direction and H degrees in the pitch direction; the relative offset of the point-type dynamic directional symbol is obtained as Originalshift, and the relative offset is a non-zero value; firstly, the theoretical display position D0 (D0x, D0y) of the point-type dynamic directional symbol is calculated, and then it is determined whether D0 exceeds the display range. If it exceeds, D0 is positionally restricted to obtain the first display position D1 (D1x, D1y) of the point-type symbol after restriction and its corresponding first relative offset Limitshift after position restriction, wherein, Calculate the theoretical display position D0, D0x = fx – Originalshift*sin(roll); D0y=fy+Originalshift*cos(roll); Determine whether D0 exceeds the display range. If the azimuth direction is within the range of [-W / 2, W / 2], and the elevation direction is within the range of [-H / 2, H / 2], it does not exceed the display range, and D0 is the first display position D1 of the point symbol, and Originalshift is the first relative offset Limitshift. Otherwise, position restriction is performed. When roll is ±90 degrees, the straight line FD0 is parallel to the X axis. Since the display range of the dynamic directivity symbol must be greater than or equal to the display range of its reference symbol, fy does not exceed the boundary, and then D0y does not exceed the boundary, so D0x exceeds the boundary. The first display position D1 and the first relative offset Limitshift after the position limit are calculated using the first preset method, where sign(X) is -1 when X is negative, otherwise it is 1, where, The first preset method is: D1 x=W / 2*sign(D0x), D1y=fy and Limitshift=(W / 2-sign(D0x)*fx)*sign(Originalshift); When rol l is 0 degrees and ±180 degrees, the straight line FD0 is parallel to the Y axis. Since fx does not exceed the limit, D0x does not exceed the limit, so D0y exceeds the limit. The second preset method is used to calculate the first display position D1 and the first relative offset Limitshift after the position limit, where: The second preset method is D1 x=fx, D1 y=H / 2*sign(D0y) and Limitshift=(H / 2–sign(D0y)*fy)*sign(Originalshift); If roll is not a preset angle, the process is as follows: Obtain the constant FD0b in the expression Y=FD0slope*X+FD0b for the straight line FD0, FD0b=fy-FD0slope*fx; Get the positions of the four vertices in the display range, and calculate the slopes of the lines connecting the reference symbol reference point F and the four vertices E, G, K, and H, which are expressed as FEslope, FGslope, FKslope, and FHslope respectively; If D0x is greater than or equal to fx, that is, D0 is on the right side of F, and if FD0slope is within the range of [FHslope, FGslope], then the intersection of the straight line FD0 and the right boundary is calculated; if FD0slope is less than FHslope, then the intersection of the straight line FD0 and the lower boundary is calculated; if FD0slope is greater than FGslope, then the intersection of the straight line FD0 and the upper boundary is calculated; If D0x is less than fx, that is, D0 is on the left side of F: if FD0slope is within the range of [FEslope, FKslope], then calculate the intersection of the straight line FD0 and the left boundary; if FD0slope is less than FEslope, then calculate the intersection of the straight line FD0 and the upper boundary; if FD0slope is greater than FKslope, then calculate the intersection of the straight line FD0 and the lower boundary; A first display position D1 of the point symbol after position restriction is determined according to the intersection point, and a first relative offset Limitshift of the point symbol after restriction is calculated, which is expressed as Limitshift=FD1*sign(Originalshift).

8. The position restriction algorithm according to claim 7, characterized in that: The second display position and the second relative offset after determining the position limit of the dynamic directional line symbol include: The vertical point from the reference symbol to the line-type dynamic directional symbol refers to drawing a vertical line from the reference point of the reference symbol to the line-type dynamic directional symbol, and the intersection of the vertical line and the line-type dynamic directional symbol is taken as the vertical point. The vertical point is the reference point of the line-type dynamic directional symbol.

9. The position restriction algorithm according to claim 8, characterized in that: In the step 3, the second display position of the line-type dynamic directional symbol after position restriction will be located within a quadrilateral range surrounded by four straight lines passing through the four vertices of the display range and parallel to the line-type symbol, and the second relative offset after position restriction is no greater than the distance from the reference symbol to the four straight lines passing through the four vertices of the display range and parallel to the line-type symbol, wherein, Get the reference point F2 of the reference symbol with coordinates (f2x, f2y), get the display range corresponding to the line symbol as a rectangular range of WB degrees in the azimuth direction and HB degrees in the pitch direction, get the initial relative shift of the line dynamic directivity symbol as Originalshift2, the relative shift is a non-zero value, get the rotation angle of the line symbol relative to the reference symbol as roll 2, including, Determine the display position F2 of the reference symbol to the vertical point position D (Dx, Dy) of the line symbol; Dx=f2x+Originalshift2*cos(rol l 2); Dy=f2y+Originalshift2*sin(rol 1 2); Determine whether D exceeds the display range. If the azimuth direction is within the range of [-WB / 2, WB / 2] and the elevation direction is within the range of [-HB / 2, HB / 2], it does not exceed the display range, D is the second display position D2, and Originalshift2 is the second relative offset Limitshift2; otherwise, position restriction is required; Since the slope of the line where the line symbol is located is required in the position restriction process, the preset angle is processed as follows: If roll 2 is ±90 degrees, the straight line F2D is parallel to the Y axis. Since the display range of the dynamic directivity symbol must be greater than or equal to the display range of its reference symbol, f2x does not exceed the bounds, so Dx does not exceed the bounds either. Therefore, Dy exceeds the bounds. The second display position and the second relative offset after the position limit are calculated using the third preset method, where sign(X) is -1 when X is negative, otherwise it is 1. The third preset method is D2x=f2x+Originalshift2*sign(Dx), D2y=f2y and Limitshift2= (HB / 2–sign(Dy)*f2y)*sign(Originalshift2); If roll 2 is 0 degrees or ±180 degrees, the straight line F2D is parallel to the X axis, and since f2y is within the bounds, Dy is also within the bounds, so Dx is within the bounds, and the second display position and the second relative offset after position restriction are calculated using the fourth preset method, where: The fourth preset method is D2x=f2x, D2y=f2y+Originalshift2*sign(Dy) and Limitshift2= (WB / 2-sign(Dx)*f2x)*sign(Originalshift2); If roll is not a preset angle, the process is as follows: Assuming that the line where the line symbol is located is line BD, then line BD is perpendicular to line F2D, so the slope BDslope of line BD can be obtained according to the rotation angle, expressed as BDslope = tan(rol l + 90); Based on the coordinates of the four vertices E2, G2, K2, and H2 in the display range and BDslope, the expression BDslope*X+b[i]=Y of the four straight lines passing through the four vertices and parallel to the straight line BD is obtained, which is expressed as follows: Upper right vertex G2: b[0] = HB / 2-WB / 2*BDslope Lower left vertex K2: b[1] = -HB / 2 + WB / 2 * BDslope Upper left vertex E2: b[2] = HB / 2 + WB / 2 * BDslope Lower right vertex H2: b[3] = -HB / 2-WB / 2*BDslope Calculate the distance Len[i] from position F2 to the four limit lines, expressed as follows, If Originalshift2 is greater than 0, the second relative shift is limited according to rol 2: When roll 2 is within the range of (0, 90), the line symbol can reach as far as the position passing through the upper right vertex G2; When roll 2 is within the range of (90, 180), the line symbol can reach as far as the position passing through the upper left vertex E2; When roll 2 is within the range of (-90, 0), the line symbol can reach as far as the position passing through the lower right vertex H2; When roll 2 is within the range of (-180, -90), the line symbol can reach as far as the position passing through the lower left vertex K2; Use the numerical limit operation Out = LIMIT (In, Min, Max), where the operation input is the data In, the limit lower boundary Min and the limit upper boundary Max, and the operation output is the data Out: when In is greater than Max, the operation output is Max; when In is less than Min, the operation output is Min; when In is within the range of [Min, Max], the operation output is In; according to the judgment result of roll 2, calculate the second relative offset Limitshift2 after position limitation, expressed as, Second relative shift Limitshift2 = LIMIT (Originalshift2, 0, len[i]); If the second relative shift Originalshift2 is less than 0, the relative shift is limited according to roll 2: When roll 2 is within the range of (0, 90), the line symbol can reach as far as the position passing through the lower left vertex K2; When roll 2 is within the range of (90, 180), the line symbol can reach as far as the position passing through the lower right vertex H2; When roll 2 is within the range of (-90, 0), the line symbol can reach as far as the position passing through the upper left vertex E2; When roll 2 is within the range of (-180, -90), the line symbol can reach as far as the position passing through the upper right vertex G2; According to the judgment result of roll 2, combined with the numerical limit operation, the second relative offset after position limitation is calculated, which is expressed as Limitshift2=LIMIT(Originalshift2,-len[i],0); According to the display position F2 of the reference symbol and the second relative offset Limitshift2, the second display position D2 of the restricted line symbol can be obtained. D2x=f2x+Limitshift2*cos(roll 2), D2y=f2y+Limitshift2*sin(roll 2).

Images