Method for realizing straight rhombic pyramid scanning by mobile satellite antenna

Abstract

A method for implementing right-angled rhombus scanning with a moving-channel antenna includes: determining the number of scanning position points. N The value of is used to determine the desired azimuth angle of the current antenna. α 0 and desired pitch angle β The value of 0; setting the scan counter. i Determine the maximum scanning offset angle in the azimuth direction. δ A Maximum scan offset angle in the pitch direction δ E The value of is taken, and the parameter is calculated. φ 1 and φ The value of 2; when i <4 N When calculating parameters θ i Calculate the scan offset angle δ i Calculate the scanning trajectory for pitch angle. β i Calculate the scanning trajectory of the azimuth angle α i Adjust antenna pointing: Control the antenna's elevation angle to rotate to a new position. β i Control the azimuth angle of the antenna to rotate to a new position. α i Update the scan counter i , i =mod(i+1,4 N Return to execution. This method is suitable for on-the-move antennas with a convex cross-section and a beam main lobe pattern, offering a wider range of applications than elliptical cone scanning and achieving a higher average received level.

Description

Technical Field

[0001] This application belongs to the field of satellite communication technology and relates to the pointing control technology of mobile antennas, specifically to a method for mobile antennas to achieve straight rhombus cone scanning. Background Technology

[0002] In a mobile communication system, slow antenna pointing deviations can be compensated for using a closed-loop pointing tracking system. During this process, the antenna scans the vicinity of the desired pointing direction in a specific manner. The closed-loop pointing tracking system acquires the received signal level during the scan and uses the signal level difference at symmetrical positions near the desired pointing direction to detect and correct the antenna pointing deviation.

[0003] For mechanical scanning systems with on-the-go communication, the commonly used scanning method is conical scanning, such as... Figure 1 As shown. Conical scanning is suitable for antennas with a circular cross-section in the main lobe pattern. For antennas with an elliptical cross-section, conical scanning will lead to a decrease in the average received signal level, such as... Figure 2 As shown. In Figure 2 In (a), the ellipse represents the isoelectric lines of the received signal when an antenna with an elliptical cross-section of the main lobe pattern scans around the desired direction. A larger ellipse indicates a larger scanning offset angle, resulting in a lower received signal level on these scanning tracks; conversely, a smaller ellipse indicates a smaller scanning offset angle, resulting in a higher received signal level on these scanning tracks. The center dot represents the received signal level when the antenna is aligned with the desired direction; the received signal level is highest at this position. The thick solid circle represents the trajectory of this antenna performing a conical scan around the desired direction. Figure 2 In (b), L ( t This indicates the change in received signal level over time during the conical scanning process of this antenna. From... Figure 2 As can be seen in (a), the ellipses (thin solid line ellipses) corresponding to points B and D in the conical scanning trajectory are the smallest, so the received level at these two points is the largest. The ellipses corresponding to other positions are all larger than the thin solid line ellipses, so the received level at these positions is lower than the received level at points B and D, resulting in a decrease in the average received level.

[0004] To address the aforementioned issues, the applicant previously submitted application number 202511674536.6, which describes a method for implementing elliptical cone scanning using a mobile antenna. Figure 3 As shown. This is a desired direction (vector) along the antenna. Looking at the direction (see), the elliptical cone scan is performed counterclockwise (hereinafter referred to as counterclockwise elliptical cone scan). A similar elliptical cone scan method is clockwise elliptical cone scan. Since the design principles of both are the same, this application will only discuss the counterclockwise elliptical cone scan as an example.

[0005] like Figure 3 As shown, the origin of the coordinate system is the centroid of the carrier. O Establish a carrier rectangular coordinate system (point) OXYZ ,in, Y The roll shaft (roll axis) points in the direction the carrier is moving. X The axis (pitch axis) is perpendicular to the vertical. The axis points to the right side of the carrier. Z The axis (azimuth axis) is perpendicular to a straight plane. OXY And pointing upwards. The antenna's pointing parameters—azimuth and elevation—are both in the coordinate system. OXYZ Characterization in: 1) with Y The axis is the 0° reference line for the azimuth angle, and the positive direction of the azimuth angle is defined according to the coordinate system. OXYZ The right-hand rule in the middle; 2) with the plane OXY The 0° reference plane is used for the elevation angle, and the antenna is pointed in the plane. OXY When pointing upwards, the pitch angle is positive.

[0006] exist Figure 3 An ellipse in space was constructed. O 2 ABCD This ellipse is obtained by intersecting an imaginary plane perpendicular to the desired direction of the antenna with the elliptical cone scanned by the antenna. A The point is that the antenna's elevation angle is increased by a scanning offset angle based on the desired pointing direction. δ E The location reached, B The point is that the antenna's azimuth angle is increased by a scanning offset angle based on the desired pointing direction. δ A The location reached, Using this ellipse, the elliptical cone scanning motion of the antenna can be mapped one-to-one. P Point on the circumference of the ellipse ABCD Motion and vectors Around the center of the ellipse O 2. The case of rotation. For example, the desired direction of the antenna—the vector. The direction corresponds to an ellipse O 2 ABCD center O 2 points; the actual pointing direction of the antenna during elliptical cone scanning—vector The direction corresponds to the ellipse circumference ABCD On P Point; the actual pointing of the antenna along the elliptical cone scanning trajectory from the vector The direction of movement to the vector direction ( ) corresponds to P Point from AStarting from point along the ellipse Exercise B point( A → B ); the antenna performing an elliptic conical scan corresponds to the vector Around the center of the ellipse O 2. Rotate.

[0007] This application will adopt the above correspondence. P Point on the circumference of the ellipse ABCD Motion and vectors Around the center of the ellipse O 2. The rotational motion is used to concisely describe the antenna's movement during an elliptical conical scan. The starting position for the antenna to perform a counter-clockwise elliptical conical scan is... A Point. Starting from this location, P Point along the circumference of the ellipse A → B→C → D → A → B… With this trajectory pattern, the antenna can achieve a continuous counterclockwise elliptical cone scan.

[0008] In practical applications, P The point does not need to move continuously, but only needs to move at equal intervals along the ellipse and cover the positions where the received level needs to be measured. Let the vector... Around the center of the ellipse O 2. Rotation angle at each step λ =360 / 4 N ( N (where the integer is positive). For the first... i ( i =0,1,…,4 N -1) Step scan, first calculate the angle θ i The value of . For example Figure 4 As shown, angle θ i It is a vector With line segment The acute angle between the two angles is calculated as follows: ; Then calculate the variable scan offset angle. δ i (That is, the angle between the actual pointing direction and the desired pointing direction when the antenna performs an elliptical cone scan): ; Next, the scan trajectory with the pitch angle is calculated. β i : ; Then calculate the increment ∆ of the azimuth scanning trajectory relative to the desired azimuth angle. α i : ; And calculate the scanning trajectory of the azimuth angle. α i , α i = α 0+ ∆ α i Finally, control the antenna's elevation angle to rotate to the new position. β i Control the azimuth angle of the antenna to rotate to a new position. α i In the above steps, α 0 is the desired azimuth angle of the antenna. β 0 is the desired elevation angle of the antenna, a variable. i The correspondence between the values ​​of and the scanning trajectory is as follows: .

[0009] This is the method for achieving counterclockwise elliptical cone scanning with an antenna. Although this method can flexibly achieve both conical and elliptical cone scanning by configuring parameters, it is still not the most appropriate choice outside the applicable scope of these two cases. Therefore, whether it is possible to design a scanning method with a wider range of applications and satisfactory performance has become a new research direction in this technological environment. Summary of the Invention

[0010] To address the shortcomings of the aforementioned existing technologies, this application provides a method for implementing a straight rhomboid scanning method for a mobile antenna. This method is applicable to mobile antennas with a convex cross-section of the main lobe pattern (i.e., the shape of the boundary of a certain two-dimensional convex set). It has a wider range of applications than elliptical cone scanning and can also achieve a higher average received level.

[0011] The present invention proposes to adopt the following technical solution: A method for implementing right-angle cone scanning with a moving-channel antenna includes: S100, Initialization: Determine the number of scan position points. N The value of is used to determine the desired azimuth angle of the current antenna. α 0 and desired pitch angle β The value of 0; setting the scan counter. i Initialize it to 0; determine the maximum scan offset angle in the azimuth direction. δ A Maximum scan offset angle in the pitch direction δ EThe value of is taken, and the parameter is calculated according to the following formula. φ 1 and φ The value of 2: φ 1 = arctan(tan δ E / tan δ A ); φ 2 = arctan(tan δ A / tan δ E ); S200, when i <4 N At that time, perform the following steps: S210, Calculation Parameters θ i : ; in, λ =360 / 4 N ; S220, Calculate the scan offset angle δ i : ; S230, Calculate the scanning trajectory for the pitch angle. β i : ; S240. Calculate the scanning trajectory of the azimuth angle. α i : α i = α 0+ ∆ α i , ∆ α i This represents the increment of the azimuth scan trajectory relative to the desired azimuth angle. ; S250. Adjust antenna pointing: Control the antenna's elevation angle to a new position. β i Control the azimuth angle of the antenna to rotate to a new position. α i ; S300, Update Scan Counter: i =mod(i+1,4 N ), and return to S200.

[0012] The beneficial effects of this invention are as follows: This invention provides a scanning method for a moving-channel antenna with a convex cross-section (i.e., the shape of the boundary of a certain two-dimensional convex set) that is suitable for the main lobe pattern of the beam. It has a wider range of applications than elliptical cone scanning and can also obtain a higher average received level. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a counterclockwise conical scan.

[0014] Figure 2 This is a schematic diagram illustrating the qualitative limitations of conical scanning applications; Figure 2 In (a), the ellipse represents the equal level line of the received signal when the antenna with an elliptical cross-section of the main lobe pattern scans around the desired direction, and the thick solid circle represents the trajectory of such antenna performing a conical scan around the desired direction. Figure 2 In (b), L ( t This indicates how the received signal level changes over time during the conical scanning process of this type of antenna.

[0015] Figure 3 This is a schematic diagram of a counterclockwise elliptical cone scan.

[0016] Figure 4 This describes the parameters. θ i A diagram illustrating the meaning.

[0017] Figure 5 This is a schematic diagram of a counterclockwise right rhomboid cone scan.

[0018] Figure 6 It is a rhombus in the azimuth-pitch two-dimensional coordinate system. O 2 ABCD A schematic diagram of the quantitative description.

[0019] Figure 7 yes Figure 6 A graph showing the relationship between the diagonal length of the rhombus and the scanning offset angle; where... Figure 7 (a) is a semi-short diagonal Length and scan offset angle δ E Relationship, Figure 7 (b) is a half-long diagonal Length and scan offset angle δ A The relationship.

[0020] Figure 8 This explains the variable scan offset angle. δ i The calculation method.

[0021] Figure 9 This explains the advantages of the rhomboid cone scanning method; among them, Figure 9 In (a), the ellipse represents the equal level line of the received signal when the antenna with an elliptical cross section of the main lobe pattern scans around the desired direction, and the solid rhombus represents the trajectory of such an antenna performing a right rhombus cone scan around the desired direction. Figure 9 In (b), L ( t This indicates the change in received signal level over time during the straight rhomboid scanning process of this type of antenna. Detailed Implementation

[0022] The design principle of this invention is as follows: First, let me explain the naming basis of a term used in this application—the right rhomboid pyramid. In geometry, the naming of pyramids usually refers to the shape of their base. For example, if the base of a pyramid is circular, it is called a cone; if the base of a pyramid is elliptical, it is called an elliptical pyramid; if the base of a pyramid is pentagonal, it is called a pentagonal pyramid. Therefore, a pyramid with a rhomboid base is called a "rhomboid pyramid." If the projection of the vertex of a pyramid onto the base is exactly at the center of the base, then this special pyramid is called a right pyramid. Therefore, a pyramid with a rhomboid base and whose projection onto the base is exactly at the center of the rhomboid is named a right rhomboid pyramid.

[0023] Next, we define a concept used in this application—the scan offset angle. The scan offset angle is the angle between the actual pointing direction and the desired pointing direction when the antenna scans in a certain manner, denoted by the symbol... δ Indicated. For example, in Figure 3 The elliptic cone scan and Figure 5 In the right rhombus cone scan shown, the vector is used The direction represents the desired direction of the antenna (i.e., the optimal direction calculated by the antenna pointing to the tracking system in the previous iteration), and the vector... The direction indicates the actual pointing of the antenna, ∠ POO 2 is the scan offset angle.

[0024] Based on the above definition and in combination Figure 3 or Figure 5 We can obtain: .

[0025] Depend on Figure 3 and Figure 5 It can be seen that when the antenna performs an elliptical cone scan or a rhomboid cone scan, the vector... The length of the antenna varies with the scanning position. Therefore, the scanning offset angle when the antenna performs an elliptical cone scan or a rhomboid cone scan is a variable, called the variable scanning offset angle. In this application, it is represented by the symbol... δ i Indicates the variable scan offset angle.i It is a variable related to the scan position.

[0026] Comparative analysis Figure 3 and Figure 5 It can be observed that, apart from the shape of the scanning trajectory, the right-angled cone scanning and the elliptical cone scanning are completely identical. The difference in the shape of the scanning trajectory is caused by the difference in the variable scanning offset angle. Therefore, it can be deduced that the calculation formulas for the right-angled cone scanning trajectory and the elliptical cone scanning trajectory should be formally identical, with the only difference being the calculation method for the variable scanning offset angle. If the calculation formula for the variable scanning offset angle when the antenna performs right-angled cone scanning can be obtained, a method for designing an antenna to achieve right-angled cone scanning can be developed.

[0027] Using the same method as in the background art, in Figure 5 Construct a rhombus in space O 2 ABCD And by using this rhombus, the motion of the antenna during the right-hand rhombus cone scan can be mapped one-to-one. P Point on the perimeter of the rhombus ABCD Motion and vectors The case of rotation around the center of the rhombus. Below, we will consider the antenna along its trajectory. A → B (In this process, variables) i From 0 to N -1) Taking counterclockwise straight rhombus scanning as an example, derive the calculation formula for the variable scanning offset angle when the antenna performs straight rhombus scanning.

[0028] Assume the maximum scanning offset angles of the antenna in the azimuth and elevation directions are respectively δ A and δ E .according to Figure 7 Know , (1) (2) like Figure 6 As shown, ∆ AO 2 B It is a right triangle. According to the geometry of right triangles, the following geometric quantities can be obtained: ; (3) ; (4) (5) For ∆ PAO 2. Applying the Law of Cosines, we get ; Organized .

[0029] Solving the above equation yields (6) For ∆ PBO 2. Applying the Law of Cosines, we get ; Organized (7) Substituting equations (3) and (6) into equation (7), we get ; Organized ; Solving the above equation yields (8) Substituting equations (1) to (3) into equation (8), we get (9) And from Figure 8 Know ; (10) Substituting equation (9) into equation (10), we get .

[0030] Finding the inverse function of the above equation yields the antenna trajectory. A → B Variable scan offset angle for counterclockwise orthorhombic conical scanning: (11) in, θ i = i λ, i =0,1,…, N-1 ,∠ ABO 2 and ∠ BAO The value of 2 is determined by equations (4) and (5) respectively.

[0031] Using a similar derivation method as above, we can obtain the following in sequence: Antenna along the trajectory B → C Variable scan offset angle for counterclockwise orthorhombic conical scanning (12) In equation (12), θ i =π- iλ, i = N , N+ 1,…,2 N-1 ; Antenna along the trajectory C → D Variable scan offset angle for counterclockwise orthorhombic conical scanning: (13) In equation (13), θ i = i λ-π, i =2 N ,2 N+ 1,…,3 N-1 ; and antenna along the trajectory D → A Variable scan offset angle for counterclockwise orthorhombic conical scanning: (14) In equation (14), θ i =2π- i λ, i =3 N ,3 N+ 1,…,4 N-1 .

[0032] Depend on Figure 6 It is easy to know: ∠ ABO 2=∠ CBO 2=∠ CDO 2=∠ ADO 2; ∠ BAO 2=∠ BCO 2=∠ DCO 2=∠ DAO 2; make φ 1=∠ ABO 2, φ 2=∠ BAO 2. By rearranging equations (11) to (14), a unified expression for the variable scanning offset angle when the antenna performs a counterclockwise right rhomboid scan can be obtained. (15) Among them, parameters θ i The possible values ​​are as follows: .

[0033] A method for implementing a right-angled cone scanning using a mobile antenna according to an embodiment of this application includes: S100, Initialization: Determine the number of scan position points. N The value of is used to determine the desired azimuth angle of the current antenna. α 0 and desired pitch angle β The value of 0; setting the scan counter. i Initialize it to 0; determine the maximum scan offset angle in the azimuth direction. δ A Maximum scan offset angle in the pitch direction δ E The value of is taken, and the parameter is calculated according to the following formula. φ 1 and φ The value of 2: φ 1 = arctan(tan δ E / tan δ A ); φ 2 = arctan(tan δ A / tan δ E ); S200, when i <4 N At that time, perform the following steps: S210, Calculation Parameters θ i : ; in, λ =360 / 4 N ; S220, Calculate the scan offset angle δ i : ; S230, Calculate the scanning trajectory for the pitch angle. β i : ; S240. Calculate the scanning trajectory of the azimuth angle. α i : α i = α 0+ ∆ α i , ∆ α i This represents the increment of the azimuth scan trajectory relative to the desired azimuth angle. ; S250. Adjust antenna pointing: Control the antenna's elevation angle to a new position. β i Control the azimuth angle of the antenna to rotate to a new position. α i ; S300, Update Scan Counter: i =mod(i+1,4 N ), and return to S200.

[0034] like Figure 9 The diagram shows the effect of applying a right-angled rhomboid scanning method to an antenna with an elliptical cross-section of the main lobe beam pattern. From... Figure 9 (b) It can be seen that, compared with conical scanning, straight rhomboid scanning can achieve a higher average received level.

[0035] The above description is only a preferred embodiment of this application and is not intended to limit this application. Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application.

Claims

1. A method for scanning a right rhombus cone using a moving-mode antenna, wherein the right rhombus cone is a pyramid with a rhomboid base and the projection of its vertex onto the base exactly at the center of the rhomboid, characterized in that... including: S100, Initialization: Determine the number of scan position points. N The value of is used to determine the desired azimuth angle of the current antenna. α 0 and desired pitch angle β The value of 0; setting the scan counter. i Initialize it to 0; determine the maximum scan offset angle in the azimuth direction. d A Maximum scan offset angle in the pitch direction d E The value of is taken, and the parameter is calculated according to the following formula. f 1 and f The value of 2: f 1=arctan(tan d E / tan d A ); f 2=arctan(tan d A / tan d E ); S200, when i <4 N At that time, perform the following steps: S210, Calculation Parameters i i : ； in, i i It is a vector With line segment The acute angle between them O 2 is a rhombus O 2 ABCD The center, line segment and line segments They are rhombuses O 2 ABCD The two diagonals, P It is a rhombus circumference ABCD The point of motion on the surface, l =360 / 4 N ; S220, Calculate the scan offset angle d i : ； S230, Calculate the scanning trajectory for the pitch angle. β i : ； S240. Calculate the scanning trajectory of the azimuth angle. α i : α i = α 0+ ∆ α i , ∆ α i This represents the increment of the azimuth scan trajectory relative to the desired azimuth angle. ； S250. Adjust antenna pointing: Control the antenna's elevation angle to a new position. β i Control the azimuth angle of the antenna to rotate to a new position. α i ; S300, Update Scan Counter: i =mod(i+1,4 N ), and return to S200.

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