Active array feed reflector multi-beam antenna pointing error calibration method

Abstract

The invention relates to an active array feed reflector multi-beam antenna pointing error calibration method, and belongs to the technical field of satellite-borne multi-beam antennas. Manufacturing an antenna according to requirements; a calibration unit is installed at the top of the reflector of the antenna; all feed source units on the Xf axis and the Yf axis in the feed source array coordinate system OfXfYf are selected as simulation units; acquiring a transmission phase # imgabs0 # of each feed source unit relative to the calibration unit in an initial state, acquiring a transmission phase # imgabs1 # of each feed source unit relative to the calibration unit on an Xf axis, acquiring a transmission phase # imgabs2 # of each feed source unit relative to the calibration unit on a Yf axis, and establishing a corresponding relation table of rotation angles and phases; according to the actually measured phase # imgabs3 # and the corresponding relation table of the rotation angle and the phase, a beam in-orbit pointing error is searched; according to the invention, on the premise of no ground calibration station, the on-orbit beam pointing error of the multi-beam antenna is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of satellite-borne multi-beam antennas and relates to a pointing error calibration method for an active array-fed reflector multi-beam antenna. Background Art

[0002] In the future, active array-fed reflector multi-beam antennas will develop in the direction of wide-area coverage, large-capacity communications, and flexible on-orbit applications. In order to increase communication capacity, it is hoped that beams with smaller beam widths will be used to cover the service area to obtain higher gain and frequency reuse times. Narrower beams bring faster gain roll-off, which places extremely high requirements on the pointing error of multi-beams.

[0003] The traditional multi-beam pointing error calibration system requires the establishment of a ground calibration station, forming sum and difference beams on the satellite, and realizing the calibration of the beam pointing error on-orbit through a single pulse calibration system. Its disadvantages are: the calibration station needs to be built at the center of the calibration beam, which places strict requirements on the site selection of the ground station, resulting in extremely high difficulty and cost in ground station construction. For fully flexible communication satellites that will occupy the main market of communication satellites in the future, the service objects and communication needs of satellite users are unknown, and it is impossible to build fixed ground calibration stations. Therefore, the traditional multi-beam pointing error calibration method cannot meet the needs of future communication satellites. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and propose a pointing error calibration method for an active array fed reflector multi-beam antenna, thereby achieving the acquisition of the on-orbit beam pointing error of the multi-beam antenna without a ground calibration station.

[0005] The solution of the present invention is:

[0006] A method for calibrating pointing errors of an active array-fed reflector multi-beam antenna, comprising:

[0007] Step 1: Make an antenna according to the requirements; install the calibration unit on the top of the antenna reflector;

[0008] Step 2: Establish the feed array coordinate system O on the antenna feed array f X f Y f ; Select X f Axis and Y f All feed units on the axis are used as simulation units;

[0009] Step 3: Obtain the transmission phase of each feed unit relative to the calibration unit in the initial state

[0010] Step 4: Establish antenna coordinate system O b X bY b ;Wrap the antenna reflector around X b Axis rotation, then around Y b Axis rotation; according to step three Get X f The transmission phase of each feed unit on the axis relative to the calibration unit Get Y f The transmission phase of each feed unit on the axis relative to the calibration unit

[0011] Step 5: Follow the X-circle method in step 4 b Axis rotation angle, around Y b Axis rotation angle, X f The transmission phase of each feed unit on the axis relative to the calibration unit Y f The transmission phase of each feed unit on the axis relative to the calibration unit Establishing a corresponding relationship table between rotation angle and phase;

[0012] Step 6: Measure the feed array X at the antenna when the antenna is in orbit. f Axis and Y f The measured phase of each feed unit on the axis According to the corresponding relationship table between the rotation angle and the phase in step 5, the on-orbit pointing error of the beam can be obtained.

[0013] In the above-mentioned method for calibrating the pointing error of an active array-fed reflector multi-beam antenna, in step one, the calibration unit is installed at the edge of the top of the reflector of the antenna.

[0014] In the above-mentioned method for calibrating the pointing error of an active array feed reflector multi-beam antenna, in step 2, the method for establishing the feed array coordinate system is:

[0015] The feed unit at the center of the feed array is taken as the coordinate origin O f ; Over O f The horizontal line is X f axis, and the right is the positive direction; f The vertical line is Y f axis, with upward being the positive direction.

[0016] In the above-mentioned method for calibrating the pointing error of an active array-fed reflector multi-beam antenna, in step 3, the transmission phase of all feed units relative to the calibration unit The method to obtain is:

[0017] S31, the reflector position of the antenna remains unchanged, and is located at the origin of the coordinate O f The feed unit is used as the reference feed;

[0018] S32, numbering the feed source units except the reference feed source as 1, 2, ..., i, ..., N;

[0019] S33, performing transmission phase simulation analysis on all feed units and calibration units; and normalizing the phases of other feed units numbered 1 to N obtained by simulation with the phase of the reference feed to obtain the transmission phase of each feed unit relative to the calibration unit in the initial state.

[0020] In the above-mentioned method for calibrating the pointing error of an active array-fed reflector multi-beam antenna, in step 4, the antenna coordinate system O b X b Y b The establishment method is:

[0021] The center point of the antenna reflector is taken as the coordinate origin O b ; Over O b The horizontal center line of the reflector is X b axis, and the right is the positive direction; b The vertical center line of the reflector is Y b axis, with upward being the positive direction.

[0022] In the above-mentioned method for calibrating the pointing error of an active array-fed reflector multi-beam antenna, the reflector of the antenna is rotated around X b Axis and Y b When the shaft rotates, it is a step rotation, and the step rotation angle is 0.01°.

[0023] In the above-mentioned active array feed reflector multi-beam antenna pointing error calibration method, X f Transmission phase of all feed units on the axis relative to the calibration unit The acquisition method is:

[0024] S41, antenna reflector around X b Axis rotation, record X f The phase of each feed unit on the axis at each step rotation angle X f Phase of all feed units on the axis at each rotation angle Normalized with respect to the reference feed phase, the normalized X f Phase of all feed units on the axis at each rotation angle

[0025]

[0026] In the formula, is the reference feed phase;

[0027] S42, after normalization, Xf Phase of all feed units on the axis at each rotation angle The transmission phase of each feed unit relative to the calibration unit in the initial state in step 3 is As the reference standard, normalization is performed to obtain X f The transmission phase of each feed unit on the axis relative to the calibration unit

[0028]

[0029] In the above-mentioned active array feed reflector multi-beam antenna pointing error calibration method, Y f Transmission phase of all feed units on the axis relative to the calibration unit The acquisition method is:

[0030] S51, antenna reflector around Y b Axis rotation, record Y f The phase of each feed unit on the axis at each step rotation angle Y f Phase of all feed units on the axis at each rotation angle Normalized relative to the reference feed phase to obtain the normalized Y f Phase of all feed units on the axis at each rotation angle

[0031]

[0032] In the formula, is the reference feed phase;

[0033] S52, after normalization, Y f Phase of all feed units on the axis at each rotation angle The transmission phase of each feed unit relative to the calibration unit in the initial state in step 3 is As the reference standard, normalization is performed to obtain Y f The transmission phase of each feed unit on the axis relative to the calibration unit

[0034]

[0035] In the above-mentioned method for calibrating the pointing error of an active array-fed reflector multi-beam antenna, in step 5, the method for establishing the corresponding relationship table between the rotation angle and the phase is:

[0036] The vertical header of the relationship table includes the b Axis rotation angle θ x and around Y b Axis rotation angle θy ;

[0037] The horizontal header of the relationship table includes X f The transmission phase and Y of each feed unit on the axis relative to the calibration unit f The transmission phase of each feed unit on the axis relative to the calibration unit.

[0038] In the above-mentioned method for calibrating the pointing error of an active array-fed reflector multi-beam antenna, in step 6, the method for obtaining the on-orbit pointing error of the beam is:

[0039] The measured phase of each feed unit Bring it into the relationship table in step 5 or Find the corresponding θ x or θ y , which is the on-orbit beam pointing error.

[0040] The beneficial effects of the present invention compared with the prior art are:

[0041] (1) The present invention realizes the calibration of multi-beam on-orbit pointing errors through the self-closed loop link of the satellite communication payload, directly solving the bottleneck problem of engineering implementation caused by the need to build ground calibration stations for traditional multi-beam satellites, and meeting the needs of satellite operators who do not want to build ground calibration stations;

[0042] (2) The present invention places a calibration unit on the structure of the reflector, combines the specific design parameters of the antenna, analyzes the transmission phase between the calibration unit and each radiating unit in the feed array, and then rotates the reflector around the antenna coordinate system to obtain the corresponding relationship between the rotation angle and the phase change value of each radiating unit, laying the foundation for the subsequent error calibration;

[0043] (3) When the antenna is in orbit, the present invention tests the transmission phase between the calibration unit and each radiating unit, and compares the corresponding relationship between the reflector rotation angle obtained by ground simulation and the phase change value of each radiating unit to obtain the rotation angle of the reflector around the X-axis and Y-axis of the antenna coordinate system relative to the theoretical design position, thereby obtaining the on-orbit pointing error of the beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a flow chart of multi-beam antenna pointing error calibration of the present invention;

[0045] Figure 2 This is a schematic diagram of the installation position of the calibration unit of the present invention;

[0046] Figure 3 is the feed array coordinate system O of the present invention f X f Y f Schematic diagram of upper feed source unit selection. DETAILED DESCRIPTION

[0047] The present invention will be further described below in conjunction with the embodiments.

[0048] The present invention adopts a method for calibrating the pointing error of an active array-fed reflector multi-beam antenna, and realizes the calibration of the on-orbit pointing error of the multi-beam through a self-closed-loop link of a satellite communication payload, directly solving the bottleneck problem of engineering implementation caused by the necessity of building a calibration station on the ground for traditional multi-beam satellites, and meeting the needs of satellite operators who do not want to build a ground calibration station.

[0049] The pointing error calibration method of active array fed reflector multi-beam antenna, such as Figure 1 As shown, the specific steps include:

[0050] Step 1: Make an antenna according to your needs; install the calibration unit on the top of the antenna reflector. Figure 2 As shown, the calibration unit is mounted at the edge of the reflector top of the antenna.

[0051] Step 2: Establish the feed array coordinate system O on the antenna feed array f X f Y f ; The method for establishing the feed array coordinate system is:

[0052] The feed unit at the center of the feed array is taken as the coordinate origin O f ; Over O f The horizontal line is X f axis, and the right is the positive direction; f The vertical line is Y f axis, with upward being the positive direction.

[0053] Select X f Axis and Y f All feed units on the axis are used as simulation units, such as Figure 3 shown.

[0054] Step 3: Obtain the transmission phase of each feed unit relative to the calibration unit in the initial state Transmission phase of all feed units relative to the calibration unit The method to obtain is:

[0055] S31, the reflector position of the antenna remains unchanged, and is located at the origin of the coordinate O f The feed unit is used as the reference feed;

[0056] S32, numbering the feed source units except the reference feed source as 1, 2, ..., i, ..., N;

[0057] S33, performing transmission phase simulation analysis on all feed units and calibration units; and normalizing the phases of other feed units numbered 1 to N obtained by simulation with the phase of the reference feed to obtain the transmission phase of each feed unit relative to the calibration unit in the initial state.

[0058] Step 4: Establish antenna coordinate system O b X b Y b . Antenna coordinate system O b X b Y b The establishment method is:

[0059] The center point of the antenna reflector is taken as the coordinate origin O b ; Over O b The horizontal center line of the reflector is X b axis, and the right is the positive direction; b The vertical center line of the reflector is Y b axis, with upward being the positive direction.

[0060] Wrap the antenna reflector around X b Rotate around the Y axis b The antenna's reflector rotates about the X axis. b Axis and Y b When the shaft rotates, it is a step rotation, and the step rotation angle is 0.01°.

[0061] According to step three Get X f The transmission phase of each feed unit on the axis relative to the calibration unit Get Y f The transmission phase of each feed unit on the axis relative to the calibration unit

[0062] X f Transmission phase of all feed units on the axis relative to the calibration unit The acquisition method is:

[0063] S41, antenna reflector around X b Axis rotation, record X f The phase of each feed unit on the axis at each step rotation angle X f Phase of all feed units on the axis at each rotation angle Normalized with respect to the reference feed phase, the normalized X f Phase of all feed units on the axis at each rotation angle

[0064]

[0065] In the formula, is the reference feed phase;

[0066] S42, after normalization, X f Phase of all feed units on the axis at each rotation angle The transmission phase of each feed unit relative to the calibration unit in the initial state in step 3 is As the reference standard, normalization is performed to obtain X f The transmission phase of each feed unit on the axis relative to the calibration unit

[0067]

[0068] Y f Transmission phase of all feed units on the axis relative to the calibration unit The acquisition method is:

[0069] S51, antenna reflector around Y b Axis rotation, record Y f The phase of each feed unit on the axis at each step rotation angle Y f Phase of all feed units on the axis at each rotation angle Normalized relative to the reference feed phase to obtain the normalized Y f Phase of all feed units on the axis at each rotation angle

[0070]

[0071] In the formula, is the reference feed phase;

[0072] S52, after normalization, Y f Phase of all feed units on the axis at each rotation angle The transmission phase of each feed unit relative to the calibration unit in the initial state in step 3 is As the reference standard, normalization is performed to obtain Y f The transmission phase of each feed unit on the axis relative to the calibration unit

[0073]

[0074] Step 5: Follow the X-circle method in step 4 b Axis rotation angle, around Y b Axis rotation angle, X f The transmission phase of each feed unit on the axis relative to the calibration unit Yf The transmission phase of each feed unit on the axis relative to the calibration unit Establish a corresponding relationship table between the rotation angle and the phase. The method for establishing the corresponding relationship table between the rotation angle and the phase is:

[0075] The vertical header of the relationship table includes the b Axis rotation angle θ x and around Y b Axis rotation angle θ y ;

[0076] The horizontal header of the relationship table includes X f The transmission phase and Y of each feed unit on the axis relative to the calibration unit f The transmission phase of each feed unit on the axis relative to the calibration unit. As shown in the figure below:

[0077]

[0078] Step 6: Measure the feed array X at the antenna when the antenna is in orbit. f Axis and Y f The measured phase of each feed unit on the axis According to the corresponding relationship table between the rotation angle and the phase in step 5, the on-orbit pointing error of the beam can be obtained.

[0079] The method to check the on-orbit pointing error of the beam is:

[0080] The measured phase of each feed unit Bring it into the relationship table in step 5 or Find the corresponding θ x or θ y , which is the on-orbit beam pointing error.

[0081] Example

[0082] The present invention is further described in detail below by taking a typical multi-beam antenna as an example:

[0083] (S1): The antenna parameters are as follows: aperture 2.6m, focal length 3.0m, number of feeds 127, antenna operating at 30GHz, calibration unit aperture 1 wavelength, calibration unit located at the top of the reflector, Figure 2 shown.

[0084] (S2): Select the feeds located on the X-axis and Y-axis on the feed array. Select the feeds such as Figure 3 As shown:

[0085] ① For feed sources No. 8, 14, 38, 50, 92, and 110 on the X-axis of the feed array, phase variation analysis is performed to obtain the relationship between the phase variation and the rotation angle of the antenna around the Y-axis;

[0086] ② For feed sources No. 11, 17, 44, 56, 101, and 119 on the Y axis of the feed array, phase variation analysis is performed to obtain the relationship between the phase variation and the rotation angle of the antenna around the X axis;

[0087] By applying the method provided by the present invention, the corresponding relationship between the rotation of the reflector around the antenna coordinate system and the phase transformation is obtained. From the actual simulation results, it can be seen that the example is consistent with the conclusion of the present invention, that is:

[0088] ① When the reflector rotates around the X-axis of the antenna coordinate system, it mainly affects the unit phase on the Y-axis of the feed array. The unit phase on the X-axis of the feed array changes slightly, but the change is very small and can be ignored;

[0089] ② When the reflector rotates around the Y-axis of the antenna coordinate system, it mainly affects the unit phase on the X-axis of the feed array. The unit phase on the Y-axis of the feed array also changes with the angle and cannot be ignored, so it needs to be corrected;

[0090] (S3) and (S4): Rotate the reflector by 0.433° (θ y | idea ), and then rotate -0.25° around the X axis (θ x | idea ), simulating the on-orbit beam pointing deviation. Under this condition, the phase analysis of the feed array is performed, and the equivalent The rotation angle θ of the reflector around the antenna coordinate system is inferred by the method in this paper (x,y) , the analytical value θ (x,y) With the theoretical rotation value θ (x,y) | idea A comparison is made to verify the calculation accuracy of this method, that is, to obtain the calibration accuracy of the on-orbit pointing error performed by this method.

[0091] ① Obtain the reflector's rotation angle θ around the Y axis of the antenna coordinate system y

[0092]

[0093] ② Obtain the reflector's rotation angle θ around the X-axis of the antenna coordinate system x

[0094] First, the angle θ of the antenna rotation around the Y axis is obtained. y "According to its influence on the Y-axis phase of the feed array, the phase on the Y-axis of the feed array is corrected, and finally the deflection angle of the antenna around the X-axis is calculated according to the corrected final phase, as shown in the following table:

[0095]

[0096]

[0097] It can be seen from the above table that the angle value of the reflector around the antenna coordinate system obtained by the method provided by the present invention is compared with the theoretical angle value. The estimated error is less than 0.003° , that is, the method is used to achieve the on-orbit pointing error of the beam Small calibration error At 0.003° , thereby ensuring high-precision on-orbit beam pointing calibration.

[0098] The present invention realizes the calibration of multi-beam on-orbit pointing errors through the self-closed-loop link of the satellite communication payload, directly solves the bottleneck problem of engineering implementation caused by the necessity of building ground calibration stations for traditional multi-beam satellites, and meets the needs of satellite operators who do not want to build ground calibration stations.

[0099] The present invention places a calibration unit on the structure of the reflector, combines the specific design parameters of the antenna, analyzes the transmission phase of the calibration unit and each radiating unit in the feed array, and then rotates the reflector around the antenna coordinate system to obtain the corresponding relationship between the rotation angle and the phase change value of each radiating unit, laying the foundation for subsequent error calibration.

[0100] When the antenna is in orbit, the present invention tests the transmission phase between the calibration unit and each radiating unit, and compares the corresponding relationship between the reflector rotation angle obtained by ground simulation and the phase change value of each radiating unit to obtain the rotation angle of the reflector around the X-axis and Y-axis of the antenna coordinate system relative to the theoretical design position, and then obtains the on-orbit pointing error of the beam.

[0101] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for calibrating pointing errors of an active array-fed reflector multi-beam antenna, characterized in that: include: Step 1: Make an antenna according to the requirements; install the calibration unit on the top of the antenna reflector; Step 2: Establish the feed array coordinate system O on the antenna feed array f X f Y f ; Select X f Axis and Y f All feed units on the axis are used as simulation units; Step 3: Obtain the transmission phase of each feed unit relative to the calibration unit in the initial state Step 4: Establish antenna coordinate system O b X b Y b ;Wrap the antenna reflector around X b Rotate around the Y axis b Axis rotation; according to step three Get X f The transmission phase of each feed unit on the axis relative to the calibration unit Get Y f The transmission phase of each feed unit on the axis relative to the calibration unit Step 5: Follow the X-circle method in step 4 b Axis rotation angle, around Y b Axis rotation angle, X f The transmission phase of each feed unit on the axis relative to the calibration unit Y f The transmission phase of each feed unit on the axis relative to the calibration unit Establishing a corresponding relationship table between rotation angle and phase; Step 6: Measure the feed array X at the antenna when the antenna is in orbit. f Axis and Y f The measured phase of each feed unit on the axis According to the corresponding relationship table between the rotation angle and the phase in step 5, the on-orbit pointing error of the beam can be obtained.

2. The method for calibrating pointing errors of an active array-fed reflector multi-beam antenna according to claim 1, characterized in that: In the step 1, the calibration unit is installed at the edge of the top of the reflector of the antenna.

3. The method for calibrating pointing errors of an active array-fed reflector multi-beam antenna according to claim 1, characterized in that: In the step 2, the method for establishing the feed array coordinate system is: The feed unit at the center of the feed array is taken as the coordinate origin O f ; Over O f The horizontal line is X f axis, and the right is the positive direction; f The vertical line is Y f axis, with upward being the positive direction.

4. The method for calibrating pointing errors of an active array-fed reflector multi-beam antenna according to claim 3, characterized in that: In step 3, the transmission phase of all feed units relative to the calibration unit The method to obtain is: S31, the reflector position of the antenna remains unchanged, and is located at the origin of the coordinate O f The feed unit is used as the reference feed; S32, numbering the feed source units except the reference feed source as 1, 2, ..., i, ..., N; S33, performing transmission phase simulation analysis on all feed units and calibration units; and normalizing the phases of other feed units numbered 1 to N obtained by simulation with the phase of the reference feed to obtain the transmission phase of each feed unit relative to the calibration unit in the initial state.

5. The method for calibrating pointing errors of an active array-fed reflector multi-beam antenna according to claim 4, characterized in that: In step 4, the antenna coordinate system O b X b Y b The establishment method is: The center point of the antenna reflector is taken as the coordinate origin O b ; Over O b The horizontal center line of the reflector is X b axis, and the right is the positive direction; b The vertical center line of the reflector is Y b axis, with upward being the positive direction.

6. The method for calibrating pointing errors of an active array-fed reflector multi-beam antenna according to claim 5, characterized in that: The reflector of the antenna is around X b Axis and Y b When the shaft rotates, it is a step rotation, and the step rotation angle is 0.01°.

7. The method for calibrating pointing errors of an active array-fed reflector multi-beam antenna according to claim 6, characterized in that: X f Transmission phase of all feed units on the axis relative to the calibration unit The acquisition method is: S41, antenna reflector around X b Axis rotation, record X f The phase of each feed unit on the axis at each step rotation angle X f Phase of all feed units on the axis at each rotation angle Normalized with respect to the reference feed phase, the normalized X f Phase of all feed units on the axis at each rotation angle In the formula, is the reference feed phase; S42, after normalization, X f Phase of all feed units on the axis at each rotation angle The transmission phase of each feed unit relative to the calibration unit in the initial state in step 3 is As the reference standard, normalization is performed to obtain X f The transmission phase of each feed unit on the axis relative to the calibration unit 8. The method for calibrating pointing errors of an active array-fed reflector multi-beam antenna according to claim 6, characterized in that: Y f Transmission phase of all feed units on the axis relative to the calibration unit The acquisition method is: S51, antenna reflector around Y b Axis rotation, record Y f The phase of each feed unit on the axis at each step rotation angle Y f Phase of all feed units on the axis at each rotation angle Normalized relative to the reference feed phase to obtain the normalized Y f Phase of all feed units on the axis at each rotation angle In the formula, is the reference feed phase; S52, after normalization, Y f Phase of all feed units on the axis at each rotation angle The transmission phase of each feed unit relative to the calibration unit in the initial state in step 3 is As the reference standard, normalization is performed to obtain Y f The transmission phase of each feed unit on the axis relative to the calibration unit 9. The method for calibrating pointing errors of an active array-fed reflector multi-beam antenna according to claim 1, characterized in that: In step 5, the method for establishing the corresponding relationship table between the rotation angle and the phase is: The vertical header of the relationship table includes the b Axis rotation angle θ x and around Y b Axis rotation angle θ y ; The horizontal header of the relationship table includes X f The transmission phase and Y of each feed unit on the axis relative to the calibration unit f The transmission phase of each feed unit on the axis relative to the calibration unit.

10. The method for calibrating pointing errors of an active array-fed reflector multi-beam antenna according to claim 9, characterized in that: In step 6, the method for obtaining the on-orbit pointing error of the beam is: The measured phase of each feed unit Bring it into the relationship table in step 5 or Find the corresponding θ x or θ y , which is the on-orbit beam pointing error.

Images