Double-anti-terahertz compact range assembly error compensation method

Abstract

The invention relates to a double-anti-terahertz compact range assembly error compensation method, which comprises the following steps of: assembling a main support structure, and removing assembly stress through high-temperature aging; a main reflector is installed on the main supporting structure, and the main reflector is calibrated; the current position of the main reflector is calibrated to a reference mirror on the side edge of the main reflector, and a test coordinate system is established based on the reference mirror; an auxiliary reflector mounting bottom plate is mounted on the main supporting structure, an auxiliary reflector is mounted on the auxiliary reflector mounting bottom plate, and the auxiliary reflector is calibrated; calculating the offset of the final position of the feed source assembly relative to the theoretical position of the feed source assembly; and with the main reflector as a reference, the position of the feed source assembly is adjusted based on the offset by adopting a high-precision six-degree-of-freedom platform, so that the feed source assembly is located at a final position. According to the invention, the assembly and calibration difficulty of the sub-reflector is effectively reduced, and the final assembly and calibration precision of the terahertz compact range system is equivalent to the test precision of an optical test instrument, namely the highest precision can be achieved.

Description

Technical Field

[0001] This application relates to the field of electronics and communications. Specifically, it relates to a method for compensating assembly errors of a dual-reflector terahertz compact range. Background Art

[0002] The terahertz compact range is used for testing terahertz antennas. The terahertz compact range has a high working frequency band and also has high requirements for the accuracy of system installation and calibration. For a dual-reflector terahertz compact range, its electrical components include a main reflector, a sub-reflector, and a feed component. The final quiet zone performance of the compact range is very sensitive to the relative positional relationship among the three, so the accuracy requirements for the installation and calibration of the three are very high. In the prior art, in the process of compensating for assembly errors of a dual-reflector terahertz compact range, there are problems of relatively large engineering difficulties and insufficient calibration accuracy. Summary of the Invention

[0003] To overcome at least one deficiency in the prior art, this application provides a method for compensating assembly errors of a dual-reflector terahertz compact range.

[0004] In a first aspect, there is provided a method for compensating assembly errors of a dual-reflector terahertz compact range, including:

[0005] Assemble the main support structure and remove the assembly stress through high-temperature aging;

[0006] Install the main reflector on the main support structure and calibrate the main reflector, with the calibration accuracy reaching an angular rotation of 0.05° and a displacement of 1 mm;

[0007] Calibrate from the current position of the main reflector to a reference mirror on the side of the main reflector, and establish a test coordinate system based on the reference mirror;

[0008] Install the sub-reflector mounting base plate on the main support structure, install the sub-reflector on the sub-reflector mounting base plate, and calibrate the sub-reflector, with the calibration accuracy reaching an angular rotation of 0.05° and a displacement of 1 mm;

[0009] Calculate the offset of the final position of the feed component relative to the theoretical position of the feed component;

[0010] Taking the main reflector as a reference, use a high-precision six-degree-of-freedom platform to adjust the position of the feed component based on the offset so that the feed component is located at the final position.

[0011] In one embodiment, to calculate the offset of the final position of the feed component relative to the theoretical position of the feed component, the following formula is used:

[0012]

[0013]

[0014] dz = kz (dx s +2Lsin(dθ / 2) 2 )

[0015] Wherein, (dx, dy, dz) is the offset, and dx, dy, and dz are the offsets in the x, y, and z axis directions in the test coordinate system respectively, and k x , k y , k z are the displacement compensation coefficients in the x, y, and z axis directions in the test coordinate system respectively, dx s , dy s , dz s are the displacement deviation amounts of the sub-reflector in the x, y, and z axis directions in the test coordinate system, dθ is the angular deviation amount of the sub-reflector, is the angular deviation direction, and L is the distance from the fitting focus of the main reflector to the origin of the test coordinate system.

[0016] In one embodiment, calibration holes are provided on the feed assembly, and the calibration holes are arranged on the plane of the conical cylinder processed integrally with the square-round transition, and the calibration holes are used to characterize the position of the feed assembly.

[0017] In one embodiment, reference holes are provided at the edge of the main reflector for characterizing the position of the main reflector.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] 1. The position of the feed is adjusted by using a high-precision six-degree-of-freedom turntable, so that the adjustment accuracy of the feed rotation angle and displacement reaches 0.001° and 0.001 mm. It can be considered that the actual position of the feed assembly is consistent with the theoretical value. As a result, the adjustment accuracy of the rotation angle and displacement of the heavier sub-reflector is relaxed from the required 0.02° and 0.2 mm to 0.05° and 1 mm, and the installation error of the actual position of the sub-reflector is compensated by the new position theoretical value of the feed assembly. The present application effectively reduces the assembly and calibration difficulty of the sub-reflector, and makes the final assembly and calibration accuracy of the terahertz compact range system equivalent to the test accuracy of an optical test instrument, that is, the highest achievable accuracy.

[0020] 2. A reference mirror is installed on the side of the main reflector where the optical measurement field of view is good and the radio frequency signal is not blocked, which is used to characterize the actual position of the main reflector after installation and represents the calibration coordinate system; using the reference mirror on the side of the main reflector as the calibration reference can minimize the installation and calibration difficulty of the main reflector to the greatest extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present application can be better understood by referring to the description given in the following text in combination with the accompanying drawings. The accompanying drawings, together with the following detailed description, are included in this specification and form a part of this specification. In the drawings:

[0022] Figure 1 The flowchart of the assembly error compensation method for a dual-reflector terahertz compact range is shown. Specific implementation manners

[0023] In the following, exemplary embodiments of the present application will be described with reference to the accompanying drawings. For clarity and conciseness, not all features of the actual embodiments are described in the specification. However, it should be understood that many embodiment-specific decisions may be made during the development of any such actual embodiment to achieve the specific goals of the developer, and these decisions may vary with different embodiments.

[0024] Here, it should also be noted that, in order to avoid obscuring the present application with unnecessary details, only the device structures closely related to the solution of the present application are shown in the drawings, while other details less related to the present application are omitted.

[0025] It should be understood that the present application is not limited to the described embodiments due to the following description with reference to the drawings. In this document, where feasible, embodiments can be combined with each other, features can be replaced or borrowed between different embodiments, and one or more features can be omitted in one embodiment.

[0026] An embodiment of the present application provides a method for compensating assembly errors of a dual-reflector terahertz compact range. Figure 1 The flowchart of the assembly error compensation method for a dual-reflector terahertz compact range is shown. Refer to Figure 1 , the method includes:

[0027] Step S1, assembling the main support structure and removing the assembly stress through high-temperature aging.

[0028] Before formally assembling the main support structure in step 1, pre-assembly and formal installation calibration can be carried out.

[0029] The pre-assembly includes:

[0030] Installing the main reflector, sub-reflector, feed component and its six-degree-of-freedom turntable on the main support structure, testing whether the relative position accuracy can meet the calibration accuracy requirements. If the adjustment links reserved for all components cannot meet the calibration dimension requirements, the installation interfaces need to be repaired. If the requirements are met, the pre-assembly work of the RF components can be carried out.

[0031] Verify the stability of the double-reflective shaping compact field under gravity conditions, complete the pre-assembly and calibration of the main reflector, sub-reflector and feed assembly, use anchors to fix the main support structure after assembly, and use an optical measuring device to test the relative position relationship of the main reflector, sub-reflector and feed assembly at least 3 times. Then, the entire compact field system is stationary for 3 to 5 days, and the optical measuring device is continued to be used to remeasure the relative position of the main reflector, sub-reflector and feed assembly, and test at least 3 times. If the overall structure remains stable and the rotation angle and displacement errors of each component are within the allowable range, it means that the main support structure has good stability under full load conditions.

[0032] A formal installation calibration includes:

[0033] The pointing coordinate system of the shaped double-reflector terahertz compact field is consistent with the coordinate system of the main reflector. Considering the high rigidity and high stability of the main reflector, a reference mirror is provided on the side of the main reflector to characterize the pointing direction of the main reflector and the compact field.

[0034] The sub-reflector and feed assembly are installed and calibrated with the main reflector as the reference. At the same time, a six-degree-of-freedom high-precision turntable is installed under the feed assembly. The angle adjustment accuracy is mdeg and the displacement adjustment accuracy is on the order of μm, and the adjustment error is almost negligible. At this time, the pointing and displacement deviations of the sub-reflector can be compensated by precisely adjusting the installation position of the feed. Therefore, the requirements for the sub-reflector's 0.02° angle accuracy and 0.2mm displacement accuracy can be relaxed.

[0035] Step S2: Install the main reflector on the main support structure and calibrate the main reflector with a calibration accuracy of 0.05° in rotation angle and 1mm in displacement.

[0036] The main reflector is large in size and heavy in weight, making it the most difficult to operate and requiring hoisting. However, considering that the main reflector itself is the calibration reference for the test, the calibration accuracy requirement does not need to be too high. After calibrating the main reflector with an accuracy of 0.05° for rotation and 1mm for displacement, pin positioning can be used to ensure the pointing position.

[0037] Step S3: calibrate the current position of the main reflector to the reference mirror on the side of the main reflector, and establish a test coordinate system based on the reference mirror. The calibration accuracy is the test accuracy of the test instrument.

[0038] Specifically, a reference hole is provided on the edge of the main reflector for indicating the position of the main reflector.

[0039] Step S4: Install the sub-reflector mounting base plate on the main support structure, install the sub-reflector on the sub-reflector mounting base plate, and calibrate the sub-reflector with a calibration accuracy of 0.05° in rotation angle and 1mm in displacement.

[0040] Since the mounting base plate holes and the sub-reflector mounting holes are both processed by CNC machine tools and have high positional accuracy relative to each other, first ensuring the positional accuracy of the mounting base plate will be of great help in the subsequent calibration and adjustment of the sub-reflector.

[0041] The sub-reflector was calibrated using a calibration fixture and the adjustment bolts on the back of the sub-reflector. The pins were positioned with an accuracy of 0.05° in rotation and 1mm in displacement, and the calibration accuracy of the system was re-measured.

[0042] Specifically, the sub-reflector calibration reference (calibration ball) is set on the mounting base plate, and a plurality of calibration balls are set, which not only ensures the test accuracy but also increases the observation range.

[0043] Step S5: Calculate the offset of the final position of the feed assembly relative to the theoretical position of the feed assembly.

[0044] Specifically, the offset of the final position of the feed assembly relative to the theoretical position of the feed assembly is calculated using the following formula:

[0045]

[0046]

[0047] dz=k z (dz s +2Lsin(dθ / 2) 2 )

[0048] Among them, (dx, dy, dz) is the offset, dx, dy, dz are the offsets of the x, y, and z axes in the test coordinate system respectively, k x 、k y 、k z They are the displacement compensation coefficients in the x, y, and z axis directions in the test coordinate system, obtained by numerical analysis method, dx s ,dy s 、dz s is the displacement deviation of the sub-reflector in the x, y, and z axis directions in the test coordinate system, obtained by measurement, dθ is the angular deviation of the sub-reflector, is the angular deviation direction, and L is the distance from the fitting focus of the main reflector to the origin of the test coordinate system.

[0049] Step S6: Using the main reflector as a reference, a high-precision six-degree-of-freedom platform is used to adjust the position of the feed assembly based on the offset so that the feed assembly is located at the final position.

[0050] Here, when the theoretical position of the feed assembly is known, the position of the feed assembly can be adjusted according to the offset so that the feed assembly is located at the final position.

[0051] Specifically, calibration holes are provided on the feed component. The calibration holes are arranged on the plane of the conical cylinder processed integrally with the square-round transition, and the calibration holes are used to characterize the position of the feed component.

[0052] In summary, the present application has the following technical effects:

[0053] 1. The position of the feed is adjusted by using a high-precision six-degree-of-freedom turntable, so that the adjustment accuracy of the feed rotation angle and displacement reaches 0.001° and 0.001 mm. It can be considered that the actual position of the feed component is consistent with the theoretical value. As a result, the adjustment accuracy of the rotation angle and displacement of the heavier sub-reflector is relaxed from the required 0.02° and 0.2 mm to 0.05° and 1 mm, and the actual position installation error of the sub-reflector is compensated by the new position theoretical value of the feed component. The present application effectively reduces the assembly and calibration difficulty of the sub-reflector, and makes the final assembly and calibration accuracy of the terahertz compact range system equivalent to the test accuracy of an optical test instrument, that is, the highest achievable accuracy.

[0054] 2. A reference mirror is installed on the side of the main reflector where the optical measurement field of view is good and the RF signal is not blocked, which is used to characterize the actual position of the main reflector after installation and represents the calibration coordinate system; using the reference mirror on the side of the main reflector as the calibration reference can minimize the installation and calibration difficulty of the main reflector to the greatest extent.

[0055] The above are only various embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for compensating assembly errors of a dual-reflector terahertz compact range, characterized in that, Including: Assemble the main support structure and remove the assembly stress by high-temperature aging; Install the main reflector on the main support structure and calibrate the main reflector with a calibration accuracy of 0.05° for rotation angle and 1 mm for displacement; Calibrate from the current position of the main reflector to the reference mirror on the side of the main reflector, and establish a test coordinate system based on the reference mirror; Install the sub-reflector mounting base plate on the main support structure, install the sub-reflector on the sub-reflector mounting base plate, and calibrate the sub-reflector with a calibration accuracy of 0.05° for rotation angle and 1 mm for displacement; Calculate the offset of the final position of the feed component relative to the theoretical position of the feed component; Taking the main reflector as the reference, use a high-precision six-degree-of-freedom platform to adjust the position of the feed component based on the offset so that the feed component is located at the final position.

2. The method according to claim 1, wherein Wherein, To calculate the offset of the final position of the feed component relative to the theoretical position of the feed component, the following formula is used: dz = k z (dz s + 2Lsin(dθ / 2) 2 ) Among them, (dx, dy, dz) is the offset, where dx, dy, and dz are the offsets in the x, y, and z axis directions of the test coordinate system, respectively, and k x , k y , k z are the displacement compensation coefficients in the x, y, and z axis directions of the test coordinate system, respectively. dx s , dy s , dz s are the displacement deviation amounts of the sub-reflector in the x, y, and z axis directions of the test coordinate system, dθ is the angular deviation amount of the sub-reflector, is the angular deviation direction, and L is the distance from the fitting focus of the main reflector to the origin of the test coordinate system.

3. The method according to claim 1, characterized in that, Calibration holes are provided on the feed component, and the calibration holes are arranged on the plane of a conical cylinder processed integrally with a square-round transition, and the calibration holes are used to characterize the position of the feed component.

4. The method according to claim 1, wherein Reference holes are provided at the edge of the main reflector for characterizing the position of the main reflector.

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