A method for biasing a secondary null of a rotating reflector antenna

Abstract

This invention provides a secondary null-position correction method for an offset rotating reflector antenna. First, a robotic arm is used to initially calibrate the null positions of the two axes, with the output shaft flange reference and the fixed shaft base mechanical reference as the calibration references. Second, in the component state, a cubic prism (prism accuracy not less than 5.5″) is attached to the antenna mechanism base and the Y-axis output shaft mechanical structure, respectively. A three-coordinate measuring machine is used to calibrate the error relationship between the coordinate systems of the two prisms and the mechanical reference coordinate system of the mechanism. Then, during the deployment test, a high-precision theodolite is used to measure the error relationship between the two prisms at the XY-axis (0, 0) position. The error between the Y-axis output shaft mechanical reference and the X-axis base mechanical reference is calculated using the aforementioned measurement errors, and the null-position correction value is updated. This eliminates the directional errors of the Y-axis output shaft mechanical reference and the X-axis base mechanical reference, thereby ensuring pointing accuracy.

Description

Technical Field

[0001] This invention relates to the field of measurement and testing technology, and specifically to a method for secondary null correction of a biased rotating reflector antenna. Background Technology

[0002] Against the backdrop of the rapid development of the satellite industry, various inter-satellite communication needs are becoming more diversified, lightweight, miniaturized, and requiring higher bandwidth and communication efficiency. In order to meet the requirements of high gain, small size and light weight for inter-satellite communication of a certain network of satellites, the original configuration of the commonly used satellite-borne Ka-band feed sub-anti-main anti-reflection integrated fixed antenna + XY type mechanism cannot meet the small size layout and weight requirements of this small and medium-sized satellite.

[0003] While the antenna with the novel offset rotating reflector structure can meet the layout and weight requirements, the original error correction method is no longer applicable. In order to ensure the on-orbit pointing accuracy of the two-dimensional mechanism of the novel offset antenna, a special pointing accuracy guarantee method for the novel antenna needs to be found. Summary of the Invention

[0004] This invention addresses the pointing accuracy problem of novel offset rotating reflector antennas by providing a secondary null-point correction method. First, a robotic arm is used to initially calibrate the null positions of the two axes, using the output shaft flange reference and the fixed shaft base mechanical reference as calibration benchmarks. Second, in the component state, a cubic prism (prism accuracy not less than 5.5″) is attached to the antenna mechanism base and the Y-axis output shaft mechanical structure, respectively. A three-coordinate measuring machine is used to calibrate the error relationship between the coordinate systems of the two prisms and the mechanical reference coordinate system of the respective mechanical structure. Then, during the deployment test, a high-precision theodolite is used to measure the error relationship between the two prisms at the XY-axis (0, 0) position. The error between the Y-axis output shaft mechanical reference and the X-axis base mechanical reference is calculated using the aforementioned measurement errors, and the null-point correction value is updated to eliminate the error between the Y-axis output shaft mechanical reference and the X-axis base mechanical reference, thereby ensuring pointing accuracy.

[0005] This invention provides a method for secondary null correction of a biased rotating reflector antenna, comprising the following steps:

[0006] S1. Calibrate the X and Y axes of the biased rotating reflector antenna to obtain the X-axis fixed-axis reference plane, X-axis moving-axis reference plane, Y-axis fixed-axis reference plane, Y-axis moving-axis reference plane, and X-axis null correction value a. x and Y-axis zero correction value a y ;

[0007] S2. Install a first cubic prism on the side of the X-axis fixed-axis reference plane. The mechanical reference coordinate system of the X-axis fixed axis is the X-axis fixed-axis coordinate system, which is (Xa, Ya, Za). The coordinate system of the first cubic prism is the first prism coordinate system, which is (X0, Y0, Z0).

[0008] The spatial angle between the X-axis fixed-axis coordinate system and the first prism coordinate system is measured in the part state to obtain the error Δax between the +Za axis and the +X0 axis, and the error Δay between the +Za axis and the +Y0 axis.

[0009] S3. Install a second cubic prism on the Y-axis fixed-axis reference plane. The mechanical reference coordinate system of the Y-axis fixed axis is the Y-axis fixed-axis coordinate system, which is (Xa2, Ya2, Za2). The second prism coordinate system of the second cubic prism is (X2, Y2, Z2).

[0010] The spatial angle relationship between the second cubic prism and the second prism coordinate system is measured in the part state to obtain the error Δa2x between the +Za2 axis and the +X2 axis, and the error Δa2y between the +Za2 axis and the +Y2 axis.

[0011] S4. When the offset rotating reflector antenna is deployed, the spatial angle relationship between the second prism coordinate system and the first prism coordinate system is measured to obtain the error Δ2x between the +Z2 axis and the +X0 axis, and the error Δ2y between the +Z2 axis and the +Y0 axis.

[0012] S5. Based on the error between the +Za axis and the +Xa2 axis, we obtain the error Δaa2x. Based on the error between the +Za axis and the +Ya2 axis, we obtain the error Δaa2y. Where, Δaa2x = Δax + Δa2x + Δ2x, Δaa2y = Δay + Δa2y + Δ2y.

[0013] S6. Obtain the new zero-position correction value a of the X-axis. x 'and the new zero-position correction value a of the Y-axis y ', where a x '=a x+ Δaa2x, a y '=a y+ Δaa2y;

[0014] S7. The new null correction value is injected into the mechanism drive control software of the bias rotating reflector antenna. The coordinate system of the bias rotating reflector antenna is (X, Y, Z). When pointing on the track, the error in the ZX plane and ZY plane of the bias rotating reflector antenna is corrected by the mechanism drive control software. A secondary null correction method for the bias rotating reflector antenna is completed.

[0015] The present invention discloses a secondary null correction method for a biased rotating reflector antenna. In a preferred embodiment, in step S1, the biased rotating reflector antenna includes a feed source, a sub-reflector, a connecting rod, and a main reflector connected sequentially to one side of the feed source, a first bracket connected to the feed source, an X-axis connected to the sub-reflector, a second bracket connected to the X-axis, an X-axis base connecting the first bracket and the second bracket, and a Y-axis connected to the main reflector. The X-axis base is the fixed axis of the X-axis, the feed source is coaxial with the X-axis base, and the X-axis is perpendicular to the Y-axis.

[0016] The secondary reflector, primary reflector, and Y-axis rotate together with the X-axis, and the beam follows the X-axis rotation. The primary reflector rotates alone with the Y-axis, and the beam follows the rotation of the Y-axis.

[0017] The X-axis fixed-axis reference plane is the plane where the X-axis base is located, and the Y-axis fixed-axis reference plane is the reference plane where the Y-axis base is located.

[0018] The secondary null correction method for an offset rotating reflector antenna described in this invention, as a preferred embodiment, has the sub-reflector having an angle of 45° with the feed axis, the mirror reflection direction being directly opposite the center of the main reflector, and the beam direction coinciding with the Y-axis.

[0019] The present invention discloses a secondary null correction method for a biased rotating reflector antenna. In a preferred embodiment, the main reflector is a parabolic structure, the center of the main reflector coincides with the Y-axis, and the angle between the mounting surface of the main reflector and the Y-axis is 45° so that the direction of the reflected beam is 90° with the incident direction of the secondary reflector.

[0020] In the preferred embodiment of the secondary null correction method for a biased rotating reflector antenna described in this invention, in step S2, the first cubic prism is mounted on the side of the second support.

[0021] In the preferred embodiment of the secondary null correction method for the biased rotating reflector antenna described in this invention, the prism accuracy of both the first cubic prism and the second cubic prism is not less than 5.5″.

[0022] The present invention provides a secondary null correction method for a biased rotating reflector antenna. In a preferred embodiment, in step S7, the new null correction value corrects the errors of the biased rotating reflector antenna, excluding random errors and satellite installation errors.

[0023] The secondary null-position correction method for an offset rotating reflector antenna described in this invention, as a preferred embodiment, involves the installation error between the offset rotating reflector antenna and the satellite being the error between the X-axis fixed-axis coordinate system and the satellite coordinate system.

[0024] This invention is proposed to solve the problem of on-orbit pointing accuracy of a novel offset-fed antenna two-dimensional mechanism when the original error correction method for the antenna with a novel offset rotating reflector structure is not applicable.

[0025] This invention relates to a method for correcting the cumulative installation error of the mechanical reference and the output mechanical reference of a two-dimensional mechanism by using a zero-position correction value. Since the zero-position correction value is given twice, it is called a method of double zero-position correction.

[0026] Specifically, the process involves: First, using a robotic arm to initially calibrate the zero positions of the two axes, with the output shaft flange reference and the fixed shaft base mechanical reference as the calibration benchmarks. Second, in the component state, a cubic prism (prism accuracy not less than 5.5″) is attached to the antenna mechanism base and the Y-axis output shaft mechanical structure, respectively. The error relationship between the coordinate systems of the two prisms and the mechanical reference coordinate system of the mechanism is then calibrated using a three-coordinate measuring instrument. During the deployment test, a high-precision theodolite is used to measure the error relationship between the two prisms at the XY axis (0, 0) position. The error between the Y-axis output shaft mechanical reference and the X-axis base mechanical reference is calculated using the aforementioned measurement errors, and the zero-position correction value is updated to eliminate the error between the Y-axis output shaft mechanical reference and the X-axis base mechanical reference, thereby ensuring pointing accuracy.

[0027] This method has a wider range of applicability, applicable to both conventional two-dimensional reflector antennas and single-axis one-dimensional scanning phased array antennas, as well as ensuring pointing error accuracy of offset rotating reflectors. Moreover, it simplifies data processing when applied.

[0028] The present invention has the following advantages:

[0029] (1) The antenna involved in this invention is a biased rotating reflector, which is different from the traditional antenna. The main reflector, the secondary reflector, and the feed source of this antenna are separated on both sides of the mechanism. Specifically, the feed source is fixed on the mounting base of the mechanism, the main and secondary reflectors and the Y-axis rotate with the X-axis, and the main reflector rotates with the Y-axis. In contrast, the main and secondary feedback sources of traditional antennas are all on a fixed overall structure. Therefore, the original antenna error measurement and correction method is no longer applicable. This invention cleverly solves this problem.

[0030] (2) In this invention, due to the long distance between the two rotating shafts, the theoretical error between the single rotating shaft and the mechanical reference under non-gravity unloading conditions is relatively large. In addition, the product is protected from rotation without gravity unloading. However, this invention successfully bypasses these two problems. It directly measures the deviation between the X-axis base and the Y-axis moving shaft mechanical reference under gravity unloading conditions during the unfolding test. The measurement results are corrected with zero-position correction value, thereby eliminating this error and achieving the purpose of correcting the installation error.

[0031] (3) In order to correct the cumulative installation error of the X-axis and Y-axis in this invention, the error measurement of the theoretical value and actual angle value of the X-axis and Y-axis under the gravity unloading environment under the original zero-position correction value was carried out, and this error was added to the zero-position correction value to obtain a new zero-position correction value and then the injection mechanism drive control software was corrected. This method is the first of its kind in actual system engineering applications.

[0032] (4) In this invention, the pointing accuracy of the photoelectric axis relative to the mechanical reference coordinate system in the dark room is <0.1° by correction, which is better than the accuracy of <0.15° of the existing conventional correction method. Attached Figure Description

[0033] Figure 1 A flowchart of a secondary null correction method for a biased rotating reflector antenna;

[0034] Figure 2 This is a schematic diagram of a biased rotating reflector antenna structure, illustrating a secondary null correction method for such an antenna.

[0035] Figure 3 This is a schematic diagram of the rotating axis X-axis structure of a secondary null correction method for a biased rotating reflector antenna.

[0036] Figure 4 This is a schematic diagram of the rotating Y-axis structure of a secondary null correction method for a biased rotating reflector antenna.

[0037] Figure 5 This is a schematic diagram of the initial zero-position calibration reference position on the X-axis for a secondary null correction method of an offset rotating reflector antenna.

[0038] Figure 6 A schematic diagram of the initial zero-position calibration reference position on the Y-axis for a secondary null correction method of an offset rotating reflector antenna;

[0039] Figure 7 An experimental side view is shown for a secondary null correction method for a biased rotating reflector antenna.

[0040] Figure 8 An experimental stereoscopic view showing a secondary null correction method for a biased rotating reflector antenna;

[0041] Figure 9 A schematic diagram of a satellite coordinate system for a secondary null correction method for an offset rotating reflector antenna;

[0042] Figure 10 A satellite coordinate system side view of a secondary null correction method for an offset rotating reflector antenna;

[0043] Figure 11 A schematic diagram of the X-axis related reference for a secondary null correction method for a biased rotating reflector antenna;

[0044] Figure 12 This is a schematic diagram of the Y-axis related reference for a secondary null correction method for a biased rotating reflector antenna.

[0045] Figure label:

[0046] 1. X-axis fixed-axis reference plane; 2. X-axis moving-axis reference plane; 3. Y-axis fixed-axis reference plane; 4. Y-axis moving-axis reference plane; 5. First cubic prism; 6. X-axis fixed-axis coordinate system; 7. First prism coordinate system; 8. Second cubic prism; 9. Y-axis fixed-axis coordinate system; 10. Second prism coordinate system; 11. Satellite coordinate system; A. Offset rotating reflector antenna; A1. Feed source; A2. Secondary reflector; A3. Connecting rod; A4. Main reflector; A5. First support; A6. X-axis; A7. Second support; A8. X-axis base; A9. Y-axis; A10. Base; A11. Beam. Detailed Implementation

[0047] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Example 1

[0048] like Figure 1 As shown, a secondary null correction method for a biased rotating reflector antenna is provided. The biased rotating reflector antenna A includes a feed A1, a sub-reflector A2, a connecting rod A3, and a main reflector A4 connected sequentially to one side of the feed A1, a first bracket A5 connected to the feed A1, an X-axis A6 connected to the sub-reflector A2, a second bracket A7 connected to the X-axis A6, an X-axis base A8 connecting the first bracket A5 and the second bracket A7, and a Y-axis A9 connected to the main reflector A4. The X-axis base A8 is the fixed axis of the X-axis, the feed A1 is coaxial with the X-axis base A8, and the X-axis A6 is perpendicular to the Y-axis A9.

[0049] The secondary reflector A2, the main reflector A4, and the Y-axis A9 rotate together with the X-axis A6. The beam A11 rotates with the X-axis A6. The main reflector A4 rotates alone with the Y-axis A9. The beam A11 rotates with the Y-axis A9.

[0050] X-axis fixed-axis reference plane 1 is the plane where X-axis base A8 is located, and Y-axis fixed-axis reference plane 3 is the reference plane where Y-axis base A10 is located;

[0051] The angle between the axis of the secondary reflector A2 and the axis of the feed A1 is 45°, the direction of the mirror reflection is directly opposite the center of the main reflector A4, and the direction of the beam A11 coincides with the axis of the Y-axis A9.

[0052] The main reflector A4 has a parabolic structure, with its center coinciding with the axis of the Y-axis A9. The angle between the mounting surface of the main reflector A4 and the Y-axis A9 is 45° so that the direction of the reflected beam A11 is 90° to the incident direction of the secondary reflector A2.

[0053] The corresponding product of this invention is Figure 2The biased rotating reflector A shown in the diagram has the following characteristics: the feed A1 is biased and separated from the main reflector A4 and the secondary reflector A2. The feed A1 is on a two-dimensional mechanism base. The main reflector A4, the secondary reflector A2, and the Y-axis A9 as a whole rotate with the X-axis A6. The beam A11 rotates with the X-axis A6. The main reflector A4 rotates alone with the Y-axis A9, and the beam A11 rotates with the Y-axis A9. This type of antenna differs from conventional symmetrical reflector antenna structures, and conventional error measurement and correction methods are not applicable to this type of antenna. Therefore, a method is proposed to correct the cumulative installation error of the two-dimensional mechanism twice using a zero-position correction value.

[0054] Includes the following steps:

[0055] S1, such as Figure 3 , 4 As shown, the zero-position correction values ​​of the offset rotating reflector antenna A on the X and Y axes are calibrated according to the conventional zero-position correction value calibration method. Specifically, the calibration surfaces are: X-axis fixed-axis reference surface 1, moving-axis reference surface 2, Y-axis fixed-axis reference surface 3, and moving-axis reference surface 4. The calibration result is an X-axis zero-position correction value of a. x The Y-axis is a y ;

[0056] S2, such as Figure 5 As shown, the fixed axis of the X-axis is the X-axis base A8, whose mechanical reference coordinate system is the fixed axis coordinate system 6 (Xa, Ya, Za). The first cubic prism 5 is mounted on the X-axis base A8, and its coordinate system is the first prism coordinate system 7 (X0, Y0, Z0). The spatial angle relationship between the first prism coordinate system 7 and the fixed axis coordinate system 6 is measured in the part state to obtain the error Δax between +Za and +X0, and the error Δay between +Za and +Y0.

[0057] S3, such as Figure 6 As shown, the Y-axis fixed axis is the Y-axis A8 base, and its mechanical reference coordinate system is the Y-axis fixed axis coordinate system 9 (Xa2, Ya2, Za2). The second cubic prism 8 is mounted on the Y-axis fixed axis, and its coordinate system is the second prism coordinate system 10 (X2, Y2, Z2). The spatial angle relationship between the Y-axis fixed axis coordinate system 9 and the second prism coordinate system 10 is measured in the part state to obtain the error Δa2x between +Za2 and +X2, and the error Δa2y between +Za2 and +Y2.

[0058] S4, such as Figures 7-12 As shown, during the unfolding experiment, the spatial angular relationship between coordinate system 7 and coordinate system 10 was measured to obtain the error Δ2x between +Z2 and +X0, and the error Δ2y between +Z2 and +Y0.

[0059] S5, calculated from S1~S4:

[0060] The error between +Za and +Xa2 is Δaa2x = Δax + Δa2x + Δ2x.

[0061] The error between +Za and +Ya2 is Δaa2y = Δay + Δa2y + Δ2y;

[0062] S6, New zero-position correction value a for the X-axis x '=a x+ Δaa2x, a y '=a y+ Δaa2y;

[0063] S7. According to the new zero-position correction value (a) x ', a y The injection mechanism drive control software, the coordinate system of the offset rotating reflector antenna A is (X, Y, Z), and when pointing on the track, the installation errors in the ZX plane and ZY plane, except for random errors and satellite installation errors, are all corrected for the antenna part errors.

[0064] S8. The installation error between the mechanism and the satellite, i.e. the X-axis fixed coordinate system 6 and the satellite coordinate system 11, can be corrected according to other conventional error correction methods.

[0065] After steps S1 to S7, most of the installation errors affecting the pointing error correction are corrected. The result of the photoelectric axis calibration in the darkroom shows that the error of the electric axis relative to the X-axis fixed coordinate system 6 is <0.1°.

[0066] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for secondary null-position correction of an offset rotating reflector antenna, characterized in that: Includes the following steps: S1. Calibrate the X-axis and Y-axis of the offset rotating reflector antenna (A) to obtain the X-axis fixed-axis reference plane (1), the X-axis moving-axis reference plane (2), the Y-axis fixed-axis reference plane (3) and the Y-axis moving-axis reference plane (4), and the X-axis null correction value a. x and Y-axis zero correction value a y ; The biased rotating reflector antenna (A) includes a feed (A1), a sub-reflector (A2), a connecting rod (A3), and a main reflector (A4) connected sequentially to one side of the feed (A1), a first bracket (A5) connected to the feed (A1), an X-axis (A6) connected to the sub-reflector (A2), a second bracket (A7) connected to the X-axis (A6), an X-axis base (A8) connecting the first bracket (A5) and the second bracket (A7), and a Y-axis (A9) connected to the main reflector (A4). The X-axis base (A8) is a fixed X-axis, the feed (A1) is coaxial with the X-axis base (A8), and the X-axis (A6) is perpendicular to the Y-axis (A9). The sub-reflector (A2), the main reflector (A4), and the Y-axis (A9) rotate together with the X-axis (A6), the beam (A11) rotates with the X-axis (A6), the main reflector (A4) rotates alone with the Y-axis (A9), and the beam (A11) rotates with the Y-axis (A9) as it rotates. The X-axis fixed axis reference plane (1) is the plane where the X-axis base (A8) is located, and the Y-axis fixed axis reference plane (3) is the reference plane where the base (A10) of the Y-axis (A9) is located; S2. Install a first cubic prism (5) on the side of the X-axis fixed-axis reference plane (1). The mechanical reference coordinate system of the X-axis fixed axis is the X-axis fixed-axis coordinate system (6), which is (Xa, Ya, Za). The coordinate system of the first cubic prism (5) is the first prism coordinate system (7), which is (X0, Y0, Z0). In the part state, the spatial angle relationship between the X-axis fixed axis coordinate system (6) and the first prism coordinate system (7) is measured to obtain the error Δax between the +Za axis and the +X0 axis, and the error Δay between the +Za axis and the +Y0 axis; S3. Install a second cubic prism (8) on the Y-axis fixed-axis reference plane (3). The mechanical reference coordinate system of the Y-axis fixed axis is the Y-axis fixed-axis coordinate system (9), which is (Xa2, Ya2, Za2). The second prism coordinate system (10) of the second cubic prism (8) is (X2, Y2, Z2). In the part state, the spatial angle relationship between the Y-axis fixed axis coordinate system (9) and the second prism coordinate system (10) is measured to obtain the error Δa2x between the +Za2 axis and the +X2 axis, and the error Δa2y between the +Za2 axis and the +Y2 axis; S4. When the offset rotating reflector antenna (A) is deployed, the spatial angle relationship between the second prism coordinate system (10) and the first prism coordinate system (7) is measured to obtain the error Δ2x between the +Z2 axis and the +X0 axis, and the error Δ2y between the +Z2 axis and the +Y0 axis. S5. Based on the error between the +Za axis and the +Xa2 axis, we obtain the error Δaa2x. Based on the error between the +Za axis and the +Ya2 axis, we obtain the error Δaa2y. Where, Δaa2x = Δax + Δa2x + Δ2x, Δaa2y = Δay + Δa2y + Δ2y. S6. Obtain the new zero-position correction value a of the X-axis. x 'and the new zero-position correction value a of the Y-axis y ', where a x '=a x+ Δaa2x, a y '=a y+ Δaa2y; S7. Adjust the new zero-position correction value (a) x ', a y The mechanism drive control software is injected into the bias rotating reflector antenna (A). The coordinate system of the bias rotating reflector antenna (A) is (X, Y, Z). When pointing on the track, the error in the ZX plane and ZY plane of the bias rotating reflector antenna (A) is corrected by the mechanism drive control software. A secondary null correction method for the bias rotating reflector antenna is completed.

2. The secondary null-position correction method for an offset rotating reflector antenna according to claim 1, characterized in that: The sub-reflector (A2) and the feed (A1) axis make an angle of 45°. The reflection direction of the sub-reflector (A2) is directly opposite the center of the main reflector (A4). The direction of the beam (A11) coincides with the axis of the Y-axis (A9).

3. The secondary null-position correction method for a biased rotating reflector antenna according to claim 2, characterized in that: The main reflector (A4) has a parabolic structure, and the center of the main reflector (A4) coincides with the axis of the Y-axis (A9). The angle between the mounting surface of the main reflector (A4) and the Y-axis (A9) is 45° so that the direction of the reflected beam (A11) is 90° with the incident direction of the secondary reflector (A2).

4. The secondary null-position correction method for an offset rotating reflector antenna according to claim 1, characterized in that: In step S2, the first cubic prism (5) is installed on the side of the second bracket (A7).

5. The secondary null-position correction method for an offset rotating reflector antenna according to claim 1, characterized in that: The prism precision of the first cubic prism (5) and the second cubic prism (8) is not less than 5.5″.

6. The secondary null-position correction method for an offset rotating reflector antenna according to claim 1, characterized in that: In step S7, the new zero-point correction value (a) x ', a y The error of the biased rotating reflector antenna (A) was corrected, except for random errors and satellite installation errors.

7. The secondary null-position correction method for an offset rotating reflector antenna according to claim 1, characterized in that: The installation error between the offset rotating reflector antenna (A) and the satellite is the error between the X-axis fixed coordinate system (6) and the satellite coordinate system (11).

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