A fixed angle tool for SAR radar antenna airborne testing

Abstract

The application provides a fixed-angle tool for SAR radar antenna on-board test, which comprises an airplane load cabin, a test tool assembly and a SAR radar antenna assembly, the SAR radar antenna assembly is installed to the test tool assembly, the test tool assembly is installed in the airplane load cabin, and the SAR radar antenna is kept at a fixed angle with the horizontal plane.The application has the beneficial effects that: the tool is suitable for SAR radar antenna subarray test, the tool can install the SAR radar antenna subarray to the airplane load cabin bearing support, has sufficient rigidity, strength and angle accuracy, and meets the imaging accuracy requirement; the tool keeps the SAR radar antenna at a fixed angle with the horizontal plane according to the design; the tool adopts a pure mechanical design, and has the advantages of low system complexity and low implementation difficulty.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of antenna airborne test, and particularly relates to a fixed angle tool for SAR radar antenna airborne test. BACKGROUND

[0002] The spaceborne SAR radar antenna is a SAR radar phased array antenna used for being carried on a synthetic aperture radar system (referred to as spaceborne SAR) on a small satellite platform. The spaceborne SAR mainly comprises a central electronic device (DCU), a SAR radar antenna and a connecting cable and the like. After the SAR satellite is launched into orbit, the SAR load software and hardware do not have the means and ability to debug and modify again, and there are certain uncertainties in the satellite launch process. Therefore, when the ground test is carried out, the various test indexes of the spaceborne SAR load system must be comprehensively evaluated.

[0003] For the ground test, the main means currently available are two kinds, one is to carry out the test by using a signal simulator, and the other is to carry out the uniform straight line motion by means of automobile carrying or airplane carrying, and to receive and transmit signals in the motion to simulate the satellite imaging on the ground in the process of on-orbit flight to carry out the test. The background of the present application is that the spaceborne SAR load is tested on the ground by means of airplane carrying to verify the performance indexes. Specifically, by means of building a test system, the imaging task parameters are designed according to the geometric relationship of the actual imaging ground objects on the ground, and the test of the functions involved in the imaging, such as signal transmission and reception, data packaging, storage and BAQ compression, is carried out on the ground. At the same time, according to the obtained image, the indexes such as target point resolution, peak sidelobe ratio, integrated sidelobe ratio and noise equivalent backscatter coefficient are calculated.

[0004] Since the project has a primary phased array antenna with an aperture of about 1m*1m, which is actually a subarray of the spaceborne phased array antenna, when the airborne imaging verification is carried out, the large-aperture SAR primary phased array antenna is used as the actual transmitting and receiving antenna. The actual directional diagram and other electrical performance indexes of the antenna have been tested in the near-field anechoic chamber and the far field. The existing airborne test tool has the problems of complex system, high construction difficulty and weak rigidity, strength and angle precision, which cannot meet the requirements of imaging precision. SUMMARY

[0005] Therefore, the present application aims to provide a fixed angle tool for SAR radar antenna airborne test to solve at least one problem in the prior art.

[0006] To achieve the above object, the technical scheme of the present application is as follows:

[0007] A fixed angle tool for SAR radar antenna airborne test, comprising an aircraft load cabin, a test tool assembly and a SAR radar antenna assembly, the SAR radar antenna assembly is installed to the test tool assembly, the test tool assembly is installed in the aircraft load cabin, and the SAR radar antenna is kept at a fixed angle with the horizontal plane.

[0008] Further, the aircraft load cabin comprises a radome and two mounting supports, the two mounting supports are arranged in parallel in the radome, a plurality of mounting hole interfaces are formed on each mounting support, and the test tool assembly is connected to the mounting support through the mounting hole interface.

[0009] Further, the SAR radar antenna assembly comprises a SAR radar antenna, an IMU unit and an APOS single machine, the SAR radar antenna is installed at the bottom of the test tool assembly, and the IMU unit and the APOS single machine are installed at the upper part of the test tool assembly.

[0010] Further, the test tool assembly comprises a main connecting support, two antenna connecting supports, two reinforcing plates, a reinforcing support, an IMU mounting plate, an APOS mounting plate and a plurality of antenna adapter blocks, the two antenna connecting supports are arranged in parallel below the mounting support through the two main connecting supports, the two main connecting supports are symmetrically arranged, one reinforcing plate is installed on one side of each main connecting support, the two reinforcing plates are also symmetrically arranged above the two antenna connecting supports, the two reinforcing plates are connected through the IMU mounting plate, the two antenna connecting supports are further connected through the reinforcing support, the APOS mounting plate is installed on one of the antenna connecting supports, and an antenna adapter block is installed at the bottom of each antenna connecting support.

[0011] Further, the reinforcing support is in the shape of a rectangular long strip, a plurality of grooves are formed on the surface of the reinforcing support, seventh hole interfaces for connecting the antenna connecting supports are formed at the two ends of the reinforcing support, and a sixth threaded hole interface for connecting the IMU mounting plate is formed in the middle of the reinforcing support.

[0012] Further, the middle part of the IMU mounting plate is in the shape of a flat plate, a boss is integrally arranged at each corner of the flat plate structure, a seventh threaded hole interface for connecting the reinforcing plate is formed on each boss, two first countersunk holes for connecting the reinforcing support are formed in the middle of the flat plate structure, and four eighth threaded hole interfaces for installing the IMU unit are also formed in the middle of the flat plate structure.

[0013] Further, a plurality of second countersunk holes and ninth threaded hole interfaces are formed on the surface of the APOS mounting plate, the second countersunk holes are used for installing the antenna connecting supports, and the ninth threaded hole interfaces are used for installing the APOS single machine.

[0014] Further, a circular notch is formed in the middle of the antenna adapter block, which is used to connect with the SAR radar antenna, and a tenth threaded hole interface is formed around the antenna adapter block, which is used to connect with the antenna connecting support.

[0015] Compared with the prior art, the fixed angle tool for SAR radar antenna airborne test has the following advantages:

[0016] The fixed angle tool for SAR radar antenna airborne test can be used for SAR radar antenna subarray testing, and can install the SAR radar antenna subarray on the aircraft load cabin bearing support, has sufficient rigidity, strength and angle accuracy, and meets the imaging accuracy requirements. The tool keeps the SAR radar antenna at a fixed angle with the horizontal plane according to the design, and has the advantages of low system complexity and low implementation difficulty. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application, and are used to interpret the illustrative embodiments of the present application and their descriptions, and do not constitute improper limitations on the present application. In the drawings:

[0018] Figure 1 The overall structure schematic diagram of the embodiment of the present application is shown in the figure;

[0019] Figure 2 The aircraft load cabin schematic diagram of the embodiment of the present application is shown in the figure;

[0020] Figure 3 The test tool assembly and SAR radar antenna assembly connection explosion schematic diagram of the embodiment of the present application is shown in the figure;

[0021] Figure 4 The test tool assembly explosion schematic diagram of the embodiment of the present application is shown in the figure;

[0022] Figure 5 The main connecting support schematic diagram of the embodiment of the present application is shown in the figure;

[0023] Figure 6 The main connecting support schematic diagram of the embodiment of the present application is shown in the figure;

[0024] Figure 7 The antenna connecting support schematic diagram of the embodiment of the present application is shown in the figure;

[0025] Figure 8 The reinforcing plate schematic diagram of the embodiment of the present application is shown in the figure;

[0026] Figure 9 The reinforcing support schematic diagram of the embodiment of the present application is shown in the figure;

[0027] Figure 10 IMU mounting plate schematic diagram for embodiments of the present application;

[0028] Figure 11 APOS mounting plate schematic diagram for embodiments of the present application;

[0029] Figure 12 Antenna adapter block schematic diagram for embodiments of the present application;

[0030] Figure 13 Test tool assembly schematic diagram for embodiments of the present application.

[0031] Legend of reference signs:

[0032] 1, aircraft payload cabin; 11, antenna cover; 12, mounting bracket; 2, test tool assembly; 21, main connecting bracket; 211, first through-hole interface; 212, second through-hole interface; 213, first threaded hole interface; 22, antenna connecting bracket; 221, second threaded hole interface; 222, mounting interface; 223, third threaded hole interface; 224, fourth threaded hole interface; 225, fifth threaded hole interface; 23, reinforcing plate; 231, third through-hole interface; 232, fourth through-hole interface; 233, fifth through-hole interface; 234, sixth through-hole interface; 24, reinforcing bracket; 241, seventh through-hole interface; 242, sixth threaded hole interface; 25, IMU mounting plate; 251, seventh threaded hole interface; 252, first countersunk hole; 253, eighth threaded hole interface; 26, APOS mounting plate; 27, antenna adapter block; 3, SAR radar antenna assembly; 31, SAR radar antenna; 32, IMU unit; 33, APOS unit. DETAILED DESCRIPTION

[0033] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0034] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] like Figure 1 As shown, a fixed-angle fixture for airborne testing of SAR radar antennas includes an aircraft payload compartment 1, a test fixture assembly 2, and a SAR radar antenna assembly 3. The SAR radar antenna assembly 3 is mounted on the test fixture assembly 2, and the test fixture assembly 2 is installed inside the aircraft payload compartment 1, so that the SAR radar antenna 3 maintains a certain angle with the ground.

[0038] Figure 2 The image shows the aircraft payload bay 1, which is a Cessna 208 manned aircraft. It mainly consists of an antenna radome 11 and a mounting bracket 12. The mounting bracket 12 is composed of two parallel load-bearing beams, each containing multiple sets of mounting through-hole interfaces. The test fixture assembly 2 is connected to the load-bearing beams through these mounting through-hole interfaces.

[0039] like Figure 3 As shown, the SAR radar antenna assembly 3 includes a SAR radar antenna 31, an IMU unit 32, and an APOS unit 33. The SAR radar antenna 31 is mounted on the lower mating surface of the test fixture assembly 2 at a fixed angle; the IMU unit 32 and the APOS unit 33 are mounted on the upper support of the test fixture assembly 2.

[0040] As shown in Figure 4 The test tool assembly 2 is made of 7075-T6 aluminum alloy, and is connected by screws. The antenna support is universal, with multiple external interfaces such as through holes and threaded holes. The test tool assembly 2 is mainly composed of a main connecting support 21, two antenna connecting supports 22, two reinforcing plates 23, a reinforcing support 24, an IMU mounting plate 25, an APOS mounting plate 26, and multiple antenna adapter blocks 27. All components are connected by screws. The test tool assembly 2 is connected to the mounting support 12 through the main connecting support 21, connected to the SAR radar antenna 31 through the two antenna connecting supports 22 and the antenna adapter blocks 27, and the reinforcing plate 23, the reinforcing support 24, and the IMU mounting plate 25 are internal connecting parts that can greatly increase the stiffness of the entire test tool assembly 2. The test tool assembly 2 has high strength, stiffness, and precision.

[0041] Figures 5-6 The main connecting support 21 is shown. It contains the following main interfaces: three groups of first through hole interfaces 211 for connecting with the mounting support 12, each group containing four through holes; two ends are second through hole interfaces 212 for connecting with the antenna connecting support 22; a group of first threaded hole interfaces 213 is left in the middle for screwing with the reinforcing plate 23.

[0042] Figure 7 The antenna connecting support 22 is shown. The antenna connecting support 22 is in a triangular shape, with the long straight angle side connected to the main connecting support 21 and the hypotenuse connected to the SAR radar antenna 31, which can maintain a certain angle between the SAR radar antenna 31 and the horizontal plane. It contains the following main interfaces: the long straight angle side has two groups of bosses with two groups of second threaded hole interfaces 221 for connecting with the main connecting support 21; the bottom surface has multiple mounting interfaces 222 for connecting with the antenna adapter blocks 27; the long straight angle side has a group of third threaded hole interfaces 223 for connecting with the APOS mounting plate 26; the long straight angle side has two groups of fourth threaded hole interfaces 224 for connecting with the reinforcing plate 23; and the fifth threaded hole interface 225 is for connecting with the reinforcing support 24. In addition to the above features, the antenna connecting support 22 adopts a hollow and reinforcing rib form to reduce weight.

[0043] Figure 8 The reinforcing plate 23 is shown. The reinforcing plate 23 is in the form of a hollow trapezoidal plate, and contains the following main interfaces: a group of third through hole interfaces 231 for connecting with the main connecting support 21, located on the short side of the trapezoid; two groups of fourth through hole interfaces 232 for connecting with the antenna connecting support 22; two fifth through hole interfaces 233 for connecting with the IMU mounting plate 25; and two sixth through hole interfaces 234 for hoisting. The fourth through hole interfaces 232, the fifth through hole interfaces 233, and the sixth through hole interfaces 234 are symmetrically distributed on the long side of the trapezoid.

[0044] Figure 9 The reinforcing bracket 24 is shown as a rectangular long strip, with a groove and reinforcing treatment in the middle to reduce weight. It includes the following main interfaces: two ends are connected to the seventh through-hole interface 241 of the fifth threaded hole interface 225 of the antenna connecting bracket 22; the middle is connected to the sixth threaded hole interface 242 of the IMU mounting plate 25.

[0045] Figure 10 The IMU mounting plate 25 is shown as a flat plate with a boss configuration, and the boss is used to increase the docking accuracy. It includes the following main interfaces: four corner high bosses are provided with the seventh threaded hole interface 251 connected to the reinforcing plate 23; two middle first countersunk holes 252 are provided for connecting the reinforcing bracket 24; four middle low bosses are provided with the eighth threaded hole interface 253 for mounting the IMU unit 32.

[0046] Figures 11-12 The APOS mounting plate 26 and the antenna adapter block 27 are shown. The APOS mounting plate 26 is connected to the antenna connecting bracket 22 through the countersunk hole, and the APOS single machine 33 is installed through the boss with threaded hole (ninth threaded hole interface). The antenna adapter block 27 is characterized by a circular notch, which facilitates external tool operation. The peripheral four tenth threaded hole interfaces are connected to the antenna connecting bracket 22, and the middle circular notch is connected to the SAR radar antenna 31.

[0047] As shown in Figure 13 The test tool assembly 2 is shown in the assembled state. The three groups of first through-hole interfaces 211 of the main connecting bracket 21 are connected to the mounting bracket 12; the second through-hole interfaces 212 of the main connecting bracket 21 are connected to the second threaded hole interfaces 221 of the antenna connecting bracket 22; the first threaded hole interfaces 213 of the main connecting bracket 21 are used to be screwed with the third through-hole interfaces 231 of the reinforcing plate 23. The fourth through-hole interfaces 232 of the reinforcing plate 23 are connected to the fourth threaded hole interfaces 224 of the antenna connecting bracket 22; the fifth through-hole interfaces 233 of the reinforcing plate 23 are connected to the seventh threaded hole interfaces 251 of the IMU mounting plate 25. The seventh through-hole interfaces 241 of the reinforcing bracket 24 at both ends are connected to the fifth threaded hole interfaces 225 of the antenna connecting bracket 22; the sixth threaded hole interfaces 242 of the reinforcing bracket 24 in the middle are connected to the first countersunk holes 252 of the IMU mounting plate. The APOS mounting plate 26 is installed on the third threaded hole interface 223 of the antenna connecting bracket 22. The antenna adapter block 27 is installed on the mounting interface 222 of the antenna connecting bracket 22. The entire test tool assembly 2 has high strength, stiffness, and holding accuracy.

[0048] The tooling is suitable for SAR radar antenna subarray testing, the tooling can install the SAR radar antenna subarray to the aircraft payload cabin bearing support, has enough rigidity, strength and angle accuracy, meets the imaging accuracy requirement; the tooling keeps the SAR radar antenna and the horizontal plane fixed angle according to the design; the tooling adopts pure mechanical design, has the advantages of low system complexity and low implementation difficulty.

[0049] Working principle of a fixed angle tooling for SAR radar antenna airborne testing:

[0050] Firstly, the main connecting support 21, two antenna connecting supports 22, two reinforcing plates 23, a reinforcing support 24, an IMU mounting plate 25 and an APOS mounting plate 26 are assembled; secondly, the IMU unit 32 and the APOS unit 33 are installed to the corresponding interface positions of the test tooling assembly 2; thirdly, the antenna adapter block 27 is installed to the SAR radar antenna 31 by using a tool; fourthly, the SAR radar antenna 31 with the antenna adapter block 27 is installed to the antenna connecting support 22 of the test tooling assembly 2; fifthly, the test tooling assembly 2 with the SAR radar antenna assembly 3 is installed to the mounting support 12 in the aircraft payload cabin 1, and then the antenna cover 11 is closed; and finally, the subsequent flight test can be carried out.

[0051] The above only describes the preferred embodiments of the present application and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A fixed angle fixture for SAR radar antenna on-board testing, characterized in that: The application relates to an aircraft load cabin (1), a test tooling assembly (2) and a SAR radar antenna assembly (3), wherein the SAR radar antenna assembly (3) is installed to the test tooling assembly (2), the test tooling assembly (2) is installed in the aircraft load cabin (1), and the SAR radar antenna (31) of the SAR radar antenna assembly (3) is kept at a fixed angle with the horizontal plane. The aircraft load cabin (1) comprises a radome (11) and two installation supports (12) which are arranged in parallel in the radome (11), a plurality of installation through hole interfaces are formed in each installation support (12), and the test tooling assembly (2) is connected to the installation support (12) through the installation through hole interface. The SAR radar antenna assembly (3) comprises a SAR radar antenna (31), an IMU unit (32) and an APOS single machine (33), the SAR radar antenna (31) is installed to the bottom of the test tooling assembly (2), and the IMU unit (32) and the APOS single machine (33) are installed to the upper portion of the test tooling assembly (2). The test tooling assembly (2) comprises a main connecting support (21), two antenna connecting supports (22), two reinforcing plates (23), a reinforcing support (24), an IMU mounting plate (25), an APOS mounting plate (26) and a plurality of antenna adapter blocks (27), the top portions of the two antenna connecting supports (22) are arranged in parallel below the installation supports (12) through the two main connecting supports (21), the two main connecting supports (21) are symmetrically arranged, one reinforcing plate (23) is arranged on one side of each main connecting support (21), the two reinforcing plates (23) are also symmetrically arranged above the two antenna connecting supports (22), the two reinforcing plates (23) are connected through the IMU mounting plate (25), the middle portions of the two antenna connecting supports (22) are further connected through the reinforcing support (24), the APOS mounting plate (26) is further arranged on one of the antenna connecting supports (22), and one antenna adapter block (27) is further arranged at the bottom of each antenna connecting support (22), and the antenna connecting support (22) is connected to the SAR radar antenna (31) through the antenna adapter block (27).

2. The fixed angle fixture for SAR radar antenna on-board testing according to claim 1, characterized in that: The reinforcing support (24) is in a rectangular strip structure, a plurality of grooves are formed in the surface of the reinforcing support (24), seventh through hole interfaces (241) for connecting the antenna connecting supports (22) are formed at the two ends of the reinforcing support (24), and a sixth threaded hole interface (242) for connecting the IMU mounting plate (25) is formed in the middle of the reinforcing support (24).

3. The fixed angle fixture for SAR radar antenna on-board testing according to claim 1, characterized in that: The middle portion of the IMU mounting plate (25) is in a plate structure, four bosses which are integrally arranged are arranged at the four corners of the plate structure, seventh threaded hole interfaces (251) for connecting the reinforcing plates (23) are formed in the four bosses, first countersunk holes (252) for connecting the reinforcing support (24) are formed in the middle of the plate structure, and eight threaded hole interfaces (253) for mounting the IMU unit (32) are further formed in the middle of the plate structure.

4. The fixed angle fixture for SAR radar antenna on-board testing according to claim 1, characterized in that: The APOS mounting plate (26) is provided with a plurality of second countersunk holes and ninth threaded hole interfaces on the surface, the second countersunk holes are used for mounting the antenna connecting support (22), and the ninth threaded hole interfaces are used for mounting the APOS single machine (33).

5. The fixed angle fixture for SAR radar antenna on-board testing according to claim 1, characterized in that: The antenna adapter block (27) is provided with a circular notch in the middle, the circular notch is used for connecting with the SAR radar antenna (31), and the antenna adapter block (27) is provided with a tenth threaded hole interface around the periphery, and the tenth threaded hole interface is used for connecting with the antenna connecting support (22).

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