An environmental simulation system for high-altitude UAV RF equipment testing

Abstract

The present application provides an environmental simulation system for testing radio frequency equipment of high-altitude unmanned aerial vehicles. The pressure control system is used to simulate the stratospheric pressure environment in a vacuum container. The heat sink temperature control system is used to control the cylindrical heat sink to simulate the stratospheric temperature environment in the vacuum container. The stratospheric airflow environment is simulated by arranging a fan in the air duct. The microwave signal generated by the radio frequency equipment is absorbed by the microwave absorption module. The infrared radiation heat flow generated by the heat flow simulation module is used to simulate the solar radiation heat flow to irradiate and heat the radio frequency equipment, thereby providing an in-situ test simulated stratospheric environment for testing the actual operating status of the radio frequency equipment of the unmanned aerial vehicle on the ground. The present application has a simple structure, occupies a small space, and can stably simulate the stratospheric temperature, pressure, airflow and equivalent solar radiation heat flow environment of the stratosphere, solving the problem in the prior art that the actual operating status of the radio frequency equipment of the unmanned aerial vehicle cannot be tested in the simulated stratospheric environment on the ground.

Description

Technical Field

[0001] The present invention relates to the field of ground special test technology, and in particular to an environmental simulation system for testing radio frequency equipment of high-altitude unmanned aerial vehicles, and specifically to an environmental simulation system for performing in-situ testing of radio frequency equipment by simulating a stratospheric environment. Background Art

[0002] The environmental parameters of the stratosphere are between the flight range of general aircraft and the orbital environment. Low-speed aircraft in the stratosphere include high-altitude drones, stratospheric airships, etc. They are important remote sensing and communication platforms. They generally operate at an altitude of 16km to 30km, with a pressure of 1.2kPa to 10.3kPa, a temperature range of -60℃ to -40℃, and a wind speed of about 20m / s. There is still a lack of basic data support for low-Reynolds number flows under low pressure, and a lack of empirical correlation support for convection and heat transfer. Simulation data often need to be corrected by experimental means. Therefore, in order to achieve the purposes of thermal model correction and thermal control system performance assessment, it is necessary to conduct thermal environment simulation tests on the key loads of high-altitude drones and stratospheric airships under a ground simulation environment. In order to form a stable, uniform and continuous wind field under low pressure, current technical solutions include recirculation and injection, among which the latter can only be used for short-term simulations and it is difficult to accurately evaluate the heat transfer characteristics.

[0003] In addition, the radar, communications and other RF payloads carried by high-altitude drones and stratospheric airships will generate a lot of heat during operation, which needs to be dissipated through structures such as openings in the fuselage. Due to their complex working profiles, they are often closed and opened many times during mission execution. RF equipment manufacturers often hope to conduct systematic testing in a real test environment and under actual working conditions.

[0004] Currently, thermal tests and RF load tests on UAV RF equipment are often conducted separately in multiple tests, and there is no system that can directly test the actual operating status of microwave RF equipment in a stratospheric environment.

[0005] Therefore, designing and inventing a UAV RF equipment testing system based on a space environment simulation container has positive practical significance. Summary of the invention

[0006] In view of the above problems, the present application aims to provide an environmental simulation system for testing high-altitude UAV RF equipment, which can stably simulate the stratospheric temperature, pressure, airflow and equivalent solar radiation heat flow environment, and provide an in-situ testing environment for testing the actual operating status of the aircraft's RF load on the ground.

[0007] The present application provides an environmental simulation system for testing radio frequency equipment of high-altitude unmanned aerial vehicles, the environmental simulation system comprising:

[0008] A vacuum container, wherein the vacuum container is connected to a pressure control system for simulating a stratospheric pressure environment;

[0009] A cylindrical heat sink is arranged inside the vacuum container and connected to a heat sink temperature control system for simulating a stratospheric temperature environment;

[0010] A cylindrical structure is arranged inside the cylindrical heat sink; an outer air duct is formed between the outer wall of the cylindrical structure and the inner wall of the cylindrical heat sink, an inner air duct is arranged inside the cylindrical structure, the outer air duct is connected with the inner air duct to form an annular recirculation air duct for simulating a stratospheric air flow environment; the inner air duct is provided with a power device for simulating a stratospheric air flow environment; a radio frequency device to be tested is installed inside the inner air duct;

[0011] A microwave absorption module, arranged in the cylindrical heat sink corresponding to the radio frequency device, and used for absorbing the microwave signal generated by the radio frequency device;

[0012] The heat flow simulation module is arranged on the cylindrical structure corresponding to the radio frequency device, and is used to generate infrared radiation heat flow to simulate solar radiation heat flow to radiate and heat the radio frequency device.

[0013] According to the technical solution provided in the embodiment of the present application, the microwave absorption module includes:

[0014] The wave-transparent plate is connected to the cylindrical structure in accordance with the radio frequency device, is integrated with the cylindrical structure, and has an inner wall flush with the inner wall of the cylindrical structure, so as to transmit the microwave signal generated by the radio frequency device to the outer air duct without affecting the air flow field, thereby preventing the microwave signal from being reflected in the inner air duct and affecting the stability of the air flow field;

[0015] The absorbing device is arranged in the external air duct, and includes a first absorbing plate coaxial with the cylindrical structure. A plurality of second absorbing plates parallel to each other are connected to the side of the first absorbing plate relatively close to the radio frequency device, and the other end of the second absorbing plate is close to the cylindrical structure, and is used to absorb the microwave signal generated by the radio frequency device to reduce the impact on the airflow field of the external air duct.

[0016] According to the technical solution provided in the embodiment of the present application, the thermal flow simulation module includes:

[0017] An infrared simulation board, corresponding to the radio frequency device, is connected to the cylindrical structure in a form, is integrated with the cylindrical structure, and has an inner wall flush with the inner wall of the cylindrical structure, and is used to generate infrared radiation heat flow to simulate solar radiation heat flow to heat the radio frequency device;

[0018] A heating rod is arranged in the infrared simulation board along the circumference of the cylindrical structure, and is used to provide a heat source to the infrared simulation board;

[0019] A heat insulation board, used to connect the infrared simulation board and the cylindrical structure to prevent the infrared simulation board from transferring heat to other parts of the cylindrical structure;

[0020] The infrared heating system is used to control the heating rod to adjust the temperature of the infrared simulation board to generate infrared radiation heat flux to simulate the solar radiation heat flux, and the infrared radiation heat flux density generated by the infrared simulation board can be adjusted by adjusting the heating temperature of the heating rod.

[0021] According to the technical solution provided in the embodiment of the present application, an equivalent heat flux simulation method is used to simulate the solar radiation heat flux.

[0022] According to the technical solution provided in the embodiment of the present application, the temperature calculation formula of the infrared simulation board required to simulate the solar radiation heat flow is:

[0023]

[0024] In the formula, Q solar is the solar radiation heat flux density, unit W / m 2 ; α is the solar absorption ratio of the radio frequency device; T heat is the temperature of the infrared simulation board, in K; T is the temperature of the surface of the RF device, in K; ε1 is the infrared emissivity of the RF device; A1 is the surface area of ​​the RF device heated by the infrared radiation heat flux, in m 2 ; X is the spatial angle coefficient between the RF device and the infrared simulation board; ε2 is the infrared emissivity of the infrared simulation board.

[0025] According to the technical solution provided in the embodiment of the present application, both the radio frequency device and the infrared simulation board are provided with temperature sensors.

[0026] According to the technical solution provided in the embodiment of the present application, the second absorbing plate is a flat plate structure and a surface with a relatively large surface area is parallel to the axis of the cylindrical structure.

[0027] According to the technical solution provided in the embodiment of the present application, the wave-transmitting plate is made of polyimide; the wave-absorbing device is made of silicon carbide or carbon foam, which has the characteristics of high hardness and low outgassing rate.

[0028] According to the technical solution provided in the embodiment of the present application, a rectifier and a turbulence reduction net for stabilizing the airflow field are sequentially arranged inside the inner air duct along the airflow direction; the rectifier includes a first honeycomb rectifier and a second honeycomb rectifier sequentially arranged along the airflow direction.

[0029] According to the technical solution provided in the embodiment of the present application, the cylindrical heat sink is a tube-fin type or honeycomb air expansion plate type heat exchange structure, and uses gas nitrogen for temperature control; the cylindrical heat sink is divided into a plurality of areas whose temperatures can be independently controlled along the direction of airflow, and are respectively connected to the cylindrical heat sink temperature control system to better realize temperature control of different areas in the air duct and ensure temperature balance of the environmental simulation system.

[0030] According to the technical solution provided in the embodiment of the present application, the radio frequency device is provided with a radiation heat flux meter for measuring the infrared radiation heat flux density generated by the infrared simulation board and reaching the surface of the radio frequency device.

[0031] In summary, the present application discloses an environmental simulation system for testing radio frequency equipment of high-altitude unmanned aerial vehicles. The beneficial effects produced by the above scheme are as follows: by arranging a cylindrical heat sink in a vacuum container, and arranging a cylindrical structure in the cylindrical heat sink, an inner air duct and an outer air duct are formed. After the inner air duct and the outer air duct are connected, an annular recirculation air duct that can circulate the airflow is formed, which greatly simplifies the structure of the environmental simulation system and reduces the space occupied by the environmental simulation system; by designing a power device for generating airflow in the inner air duct, the simulation of the stratospheric airflow environment is achieved; by simulating the stratospheric pressure environment in the vacuum container through the pressure control system, and by controlling the cylindrical heat sink through the heat sink temperature control system to simulate the stratospheric temperature environment in the vacuum container; by A microwave absorption module is designed in the cylindrical heat sink to absorb microwave signals generated by the radio frequency equipment. A heat flow simulation module is connected to the cylindrical structure to generate infrared radiation heat flux to simulate solar radiation heat flux for radiant heating of the radio frequency equipment. This ensures that the conditions for conducting thermal tests on the radio frequency equipment of the unmanned aerial vehicle are met without increasing the complexity of the environmental simulation system and without affecting the airflow field of the inner air duct. Ultimately, the stratospheric temperature, pressure, airflow and solar radiation heat flux environment can be stably simulated, providing a simulated stratospheric environment for in-situ testing of the actual operating status of the radio frequency equipment of the unmanned aerial vehicle on the ground, solving the problem in the prior art that the actual operating status of the radio frequency equipment of the unmanned aerial vehicle cannot be directly tested in the stratospheric environment.

[0032] In a certain scheme of the present application, the heat flow simulation module includes an infrared simulation plate connected to the cylindrical structure through an insulation plate and a heating rod arranged inside the infrared simulation plate along the circumference of the cylindrical structure, and the inner wall of the infrared heating plate is flush with the inner wall of the cylindrical structure, thereby realizing the integration of the heat flow simulation module and the cylindrical structure, generating infrared radiation heat flux without affecting the airflow field in the inner duct, and simulating the solar radiation heat flux to radiate and heat the radio frequency equipment, thereby solving the problem in the prior art that the stability of the airflow field is affected by setting a heating structure of the radio frequency equipment in the air duct, and ensuring the effectiveness and accuracy of thermal tests simulating solar radiation heat flux on the UAV radio frequency equipment without affecting the airflow field in the air duct and the actual operating state of the UAV radio frequency equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features, objects and advantages of the present application will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings.

[0034] Figure 1 This is a schematic diagram of an environmental simulation system for testing high-altitude UAV radio frequency equipment according to an embodiment of the present application.

[0035] Figure 2 This is a cross-sectional schematic diagram of a test area of ​​an environmental simulation system for testing high-altitude unmanned aerial vehicle radio frequency equipment in an embodiment of the present application.

[0036] In the figure, 101, cylindrical heat sink; 102, vacuum container; 103, pressure control system; 103-1, exhaust pipeline; 103-2, air supply pipeline; 201, inlet connector; 202, rectifier area; 202-1, first honeycomb rectifier; 202-2, second honeycomb rectifier; 202-3, turbulence reduction net; 203, test area; 203-1, infrared simulation board; 203-2, wave-transmitting board; 203 -3, wave absorbing device; 203-4, heat shield; 203-5, radiation heat flux meter; 203-6, heating rod; 203-7, cylindrical structure; 204, gradual expansion zone; 205, power zone; 205-1, head cover; 205-2, support frame; 205-3, fan blades; 205-4, tail cover; 205-5, motor; 205-6, anti-torsion guide vane; 206, outlet connector; 301, radio frequency equipment. DETAILED DESCRIPTION

[0037] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant inventions, rather than to limit the inventions. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings. The present application is described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0038] like Figures 1-2 An environmental simulation system for testing radio frequency equipment of high-altitude unmanned aerial vehicles is shown, and the environmental simulation system includes:

[0039] A vacuum container 102, wherein the vacuum container 102 is connected to a pressure control system for simulating a stratospheric pressure environment;

[0040] The cylindrical heat sink 101 is arranged inside the vacuum container 102 and is connected to a heat sink temperature control system for simulating the stratospheric temperature environment;

[0041] The cylindrical structure 203-7 is arranged inside the cylindrical heat sink 101; an outer air duct is formed between the outer wall of the cylindrical structure 203-7 and the inner wall of the cylindrical heat sink 101, and an inner air duct is arranged inside the cylindrical structure 203-7, and the outer air duct is connected with the inner air duct to form an annular recirculation air duct for simulating the stratospheric air flow environment; the inner air duct is provided with a power device for simulating the stratospheric air flow environment; the radio frequency device 301 to be tested is installed inside the inner air duct;

[0042] A microwave absorption module, which is arranged in the cylindrical heat sink 101 corresponding to the radio frequency device 301 and is used to absorb the microwave signal generated by the radio frequency device 301;

[0043] The heat flow simulation module is arranged on the cylindrical structure 203 - 7 corresponding to the radio frequency device 301 , and is used to generate infrared radiation heat flow to simulate solar radiation heat flow to radiate and heat the radio frequency device 301 .

[0044] Among them, the cylindrical structure 203-7 and the cylindrical heat sink 101 are both cylindrical and coaxially arranged; the inner air duct includes a rectifying area 202, a test area 203, a gradual expansion area 204 and a power area 205 arranged in sequence along the air flow direction, the inner diameter of the test area 203 is smaller than the inner diameter of the power area 205, and the test area 203 and the power area 205 are connected through the gradual expansion area 204; the radio frequency device 301 is provided with a radio frequency load capable of emitting microwaves; the two ends of the inner air duct and the outer air duct are connected respectively through an inlet connector 201 and an outlet connector 206, and the airflow will make a 180° turn at the inlet connector 201 and the outlet connector 206, thereby forming an annular recirculation air duct, which has a simple structure and greatly reduces the occupied space of the environmental simulation system; the microwave absorption module is located above the radio frequency load of the radio frequency device 301, and the heat flow simulation module is arranged below the radio frequency device 301 corresponding to the microwave absorption module.

[0045] The power device is installed in the inner air duct power area 205, which can drive the gas flow in the vacuum container 102 and simulate the stratospheric airflow environment in the air duct; the rectifier area 202 is provided with rectifiers and turbulence reduction nets 202-3 in sequence along the airflow direction; the rectifier includes a first honeycomb rectifier 202-1 and a second honeycomb rectifier 202-2 arranged in sequence along the airflow direction, which can adjust the airflow passing through the inlet connector 201 into a stable airflow with consistent direction and speed.

[0046] The vacuum container 102 is a cylindrical stainless steel tank container, which can withstand a negative pressure of 1 standard atmospheric pressure, and simulate the pressure environment of the stratosphere through the pressure control system 103; the cylindrical heat sink 101 is a tube-fin type or honeycomb air expansion plate type heat exchange structure, which is installed inside the vacuum container 102 and coaxial with the vacuum container 102, and uses nitrogen for temperature control; the cylindrical heat sink 101 is divided into at least 10 areas with independently adjustable temperatures along the air flow direction, and is respectively connected to the heat sink temperature control system, and the heat sink temperature control system is provided with an automatic control module, which can automatically adjust the temperature of each area through the temperature sensor in the vacuum container 102 during the actual operation test of the radio frequency device 301, so as to better adjust the temperature of different areas in the air duct, simulate the stratospheric temperature environment, and ensure that the temperature of the stratospheric environment simulation system remains balanced during the test.

[0047] The environmental simulation system can simulate the pressure environment (i.e., vacuum environment), low temperature environment, gas flow environment, and solar radiation environment of the stratosphere to meet the requirements of testing the UAV RF device 301 in an actual working state on the ground, so as to obtain the actual state data of the UAV RF device 301 when working in the stratosphere, thereby providing more reliable data support for optimizing the design of the UAV RF device 301.

[0048] In some embodiments, the microwave absorption module includes,

[0049] The wave-transparent plate 203-2 is located in the test area 203 of the inner wind duct, and is connected to the cylindrical structure 203-7 corresponding to the radio frequency device 301, and the inner wall is flush with the inner wall of the cylindrical structure 203-7;

[0050] The absorbing device 203-3 is arranged in the external air duct and includes a first absorbing plate coaxial with the cylindrical structure 203-7. A side of the first absorbing plate relatively close to the radio frequency device 301 is connected to a plurality of second absorbing plates parallel to each other, and the other end of the second absorbing plate is close to the cylindrical structure 203-7.

[0051] The cylindrical structure 203-7 is provided with a wave-transmitting hole matching the wave-transmitting plate 203-2. The wave-transmitting plate 203-2 is connected to the cylindrical structure 203-7 through the wave-transmitting hole to form an integrated structure with the cylindrical structure 203-7. After the connection, a smooth inner wind duct is formed inside to ensure the stability of the airflow field in the test area 203. The wave-transmitting plate 203-2 is made of polyimide, which can transmit the microwave signal generated by the radio frequency load of the radio frequency device 301 to the outer wind duct to prevent it from being reflected in the inner wind duct and affecting the stability of the airflow. The wave absorbing device 203-3 is made of carbon. It is made of silicon or carbon foam, has the characteristics of high hardness and low degassing rate, and can absorb microwave signals passing through the wave-transparent plate 203-2 to prevent it from being reflected in the external wind duct and affecting the stability of the airflow, so as to reduce the impact on the airflow in the external wind duct; the first absorbing plate is an arc-shaped plate coaxial with the cylindrical structure 203-7, and a plurality of second absorbing plates parallel to each other are connected to the side of the arc-shaped plate relatively close to the radio frequency device 301, and the other end of the second absorbing plate is close to the wave-transparent plate 203-2, so that the microwave signal can be absorbed and the impact of the absorbing device 203-3 on the airflow can be minimized.

[0052] In some embodiments, the second absorbing plate is a flat plate structure and a surface with a relatively large surface area is parallel to the axis of the cylindrical structure 203-7. Figure 2 shown.

[0053] Among them, the coverage range of the absorbing device 203-3 is larger than the radiation range of the microwave signal after passing through the wave-transparent plate 203-2, so that it can completely capture and absorb the microwave signal, and the second wave-transparent plate with a flat plate structure can also pre-rectify the airflow passing through here, and cooperate with the rectifier and turbulence reduction net 202-3 to further improve the stability of the airflow field.

[0054] In some embodiments, the thermal flow simulation module includes,

[0055] The infrared simulation board 203-1 is located in the test area 203, and is connected to the cylindrical structure 203-7 corresponding to the radio frequency device 301, and the inner wall is flush with the inner wall of the cylindrical structure 203-7, and is structurally integrated with the cylindrical structure 203-7, and is used to generate infrared radiation heat flow to simulate solar radiation heat flow to heat the radio frequency device 301;

[0056] A heating rod 203-6 is disposed in the infrared simulation board 203-1 along the circumference of the cylindrical structure 203-7, and is used to provide a heat source for the infrared simulation board 203-1;

[0057] The heat insulation board 203-4 is used to connect the infrared simulation board 203-1 and the cylindrical structure 203-7 to prevent the infrared simulation board 203-1 from transferring heat to other parts of the cylindrical structure 203-7;

[0058] The infrared heating system is used to control the heating rod 203-6 to adjust the infrared simulation board 203-1 to generate infrared radiation heat flux to simulate the solar radiation heat flux.

[0059] The cylindrical structure 203-7 is provided with an infrared hole matching the infrared simulation board 203-1, and the infrared simulation board 203-1 is installed on the infrared hole of the cylindrical structure 203-7 through the heat insulation board 203-4, specifically located below the radio frequency device 301, as shown in FIG. Figure 1 As shown, it forms an integrated structure with the cylindrical structure 203-7, and after the connection, a smooth internal wind duct is formed inside, which ensures the stability of the airflow field in the test area 203; the cylindrical structure 203-7 is connected with the wave-transmitting plate 203-2 and the infrared simulation plate 203-1 to form a circumferentially closed test area 203.

[0060] In the infrared simulation board 203-1, 7 heating rods 203-6 are evenly distributed along the circumference of the cylindrical structure 203-7. Figure 2 As shown, the infrared heating system controls the heating rod 203-6 to heat the infrared simulation board 203-1, and the infrared simulation board 203-1 generates infrared radiation heat flow, and the infrared radiation heat exchange between the infrared simulation board 203-1 and the radio frequency device 301 can be adjusted by controlling the temperature of the infrared simulation board 203-1, so that the radio frequency device 301 can keep absorbing the infrared radiation heat flow generated by the infrared simulation board 203-1 during the entire test period, thereby realizing the equivalent heat flow simulation of the solar radiation heat flow. At the same time, by adjusting the temperature of each area of ​​the cylindrical heat sink 101 with gas nitrogen, the flow field temperature rise brought by the heating rod 203-6 can also be balanced and adjusted.

[0061] The principle of equivalent heat flux simulating solar radiation heat flux:

[0062] The solar radiation heat flux absorbed by the radio frequency device 301 in the stratosphere is,

[0063] Q in =α*Q solar (1)

[0064] In the formula, Q solar is the solar radiation heat flux density, unit W / m 2 ; α is the solar absorption ratio of the radio frequency device 301; Q in is the solar radiation heat flux absorbed per unit area of ​​the radio frequency device 301, in W / m 2 .

[0065] The radiant heat flux of the infrared simulation board 203-1 absorbed by the radio frequency device 301 in the environmental simulation system is,

[0066]

[0067] Wherein, Q is the radiant heat flux of the infrared simulation board 203 - 1 absorbed by the radio frequency device 301 in the environmental simulation system.

[0068] According to the equivalent heat flow simulation method, the solar radiation heat flow absorbed by the radio frequency device 301 in the stratosphere is equal to the radiation heat flow absorbed by the infrared simulation board 203-1 in the environmental simulation system, that is,

[0069]

[0070] In the formula, Q solar is the solar radiation heat flux density, unit W / m 2 ; α is the solar absorption ratio of the radio frequency device 301; T heat is the temperature of the infrared simulation board 203-1, in K; T is the surface temperature of the RF device 301, in K; ε1 is the infrared emissivity of the RF device 301; A1 is the surface area of ​​the RF device 301 heated by the infrared radiation heat flow, in m 2 ; X is the spatial angle coefficient between the radio frequency device and the infrared simulation board 203-1; ε2 is the infrared emissivity of the infrared simulation board 203-1.

[0071] It can be known from formula (3) that when the structure, installation position, material, solar radiation heat flux density and other parameters of the infrared simulation board 203-1 and the radio frequency device 301 are determined, only T heat , T is a variable, so as the temperature T of the surface of the RF device 301 changes, the temperature T of the infrared simulation board 203-1 is adjusted by the heating rod 203-6. heat The equivalent simulation of solar radiation heat flow can be achieved.

[0072] In some embodiments, both the radio frequency device 301 and the infrared simulation board 203 - 1 are provided with temperature sensors.

[0073] Among them, in the initial stage of the test, as the RF load in the RF device 301 runs for a long time, the internal temperature of the RF device 301 gradually increases, that is, the temperature on the surface of the RF device 301 increases, and the heat flow exchange between the RF device 301 and the infrared simulation board 203-1 changes, and it can no longer equivalently simulate the solar radiation heat flow. Therefore, at this time, it is necessary to adjust the temperature of the infrared simulation board 203-1 according to the temperature of the RF device 301 to maintain the ability to equivalently simulate the solar radiation heat flow. Specifically, the infrared heating system is provided with an automatic temperature control module, which collects the temperature data of the radio frequency device 301 in real time through a temperature sensor, calculates the temperature of the corresponding infrared simulation board 203-1 according to formula (3), and then controls the heating rod 203-6 to adjust the infrared simulation board 203-1 to the temperature required for equivalent simulation of solar radiation heat flow according to the temperature data of the infrared heating board 203-1 collected in real time by the temperature sensor, and then maintains the temperature of the heating rod 203-6, so that the infrared simulation board 203-1 can always generate infrared radiation heat flow that is equivalent to simulating solar radiation heat flow, thereby always maintaining the equivalent solar radiation heat flow required for the test of the radio frequency device 301.

[0074] In some embodiments, the radio frequency device 301 is provided with a radiation heat flux meter 203-5 for measuring the infrared radiation heat flux density generated by the infrared simulation board 203-1 and reaching the surface of the radio frequency device 301, as a measure to assist in monitoring whether the infrared simulation board 203-1 has an equivalent effect of simulating the solar radiation heat flux. Once the infrared radiation heat flux density data is found to be abnormal, the test can be stopped to check and eliminate the problem.

[0075] In certain embodiments, such as Figure 1 As shown, the power device is a fan; in the inner air duct power area 205, the fan is provided with an anti-twist guide plate 205-6 for reducing the airflow rotation speed on the side relatively far away from the radio frequency device 301, so that the airflow flow direction is parallel to the inner air duct direction, thereby optimizing the airflow field; the fan is provided with a head cover 205-1 and a tail cover 205-4 for airflow guidance, thereby optimizing the airflow field.

[0076] The fan shown is installed in the middle of the power zone 205 through a support frame 205-2, and the front and rear ends of the fan are respectively provided with a head cover 205-1 and a tail cover 205-4 for airflow diversion; the motor 205-5 is installed inside the tail cover 205-4, which is used to drive the fan blades 205-3 to rotate and generate airflow; since the initial airflow has a high circumferential rotation speed, it is a rotating airflow, which is not conducive to forming a stable airflow flow field and simulating the stratospheric environment, so an anti-twist guide plate 205-6 for reducing the airflow rotation speed is set at the tail end of the power zone 205, that is, downwind of the fan, so that the airflow flow direction is parallel to the air duct direction, the airflow flow field is optimized, and the stratospheric airflow is simulated. Through the fan, a continuous circulating airflow can be formed in the annular recirculation air duct.

[0077] A wind speed sensor is provided on the cylindrical structure 203 - 7 between the rectifying area 202 and the radio frequency device 301 for detecting the speed of the airflow and controlling the fan to generate the airflow environment required for the test according to the speed of the airflow.

[0078] In some embodiments, the vacuum container 102 is connected to an air extraction pipeline 103 - 1 and an air supply pipeline 103 - 2 ; the air extraction pipeline 103 - 1 and the air supply pipeline 103 - 2 are respectively connected to the pressure control system 103 .

[0079] Among them, during the test of the radio frequency device 301, due to the temperature rise of the environmental simulation system and the slow entry of external gas into the vacuum container 102, the pressure inside the vacuum container 102 will increase. At this time, it is necessary to operate the pressure control system 103 to extract the internal gas through the exhaust pipeline 103-1 to reduce the pressure inside the vacuum container 102 and maintain the pressure balance of the environmental simulation system; and due to the temperature drop of the environmental simulation system, the pressure inside the vacuum container 102 will decrease. At this time, it is necessary to operate the pressure control system 103 to inject gas into the vacuum container 102 through the gas replenishment pipeline 103-2 to increase the pressure inside the vacuum container 102 and maintain the pressure balance of the environmental simulation system; the gas is an oxygen-nitrogen mixed gas or pure nitrogen. The pressure control system 103 has an automatic control module, which can automatically exhaust or replenish gas according to the pressure change of the pressure sensor in the vacuum container 102, so as to achieve the pressure balance in the vacuum container 102 during the test of the radio frequency device 301 and maintain it at a predetermined stratospheric pressure, and its pressure control accuracy can reach ±5Pa.

[0080] When using this environment simulation system, the following steps are included:

[0081] Complete the preparatory work, including installing the radio frequency equipment 301, arranging the temperature sensor, connecting the measurement cable, etc.;

[0082] The pressure control system 103 is turned on, and the vacuum container 102 is evacuated to a vacuum for dehumidification, and the vacuum degree is preferably below 10Pa, and then the gas is introduced to a predetermined pressure, that is, the pressure environment of the stratosphere is simulated, and then the pressure control system 103 is set to enter the automatic control mode;

[0083] Turn on the heat sink temperature control system to reduce the temperature in the vacuum container 102 to a set temperature, that is, to simulate the temperature environment of the stratosphere, generally between -80 and -30°C, and then set the heat sink temperature control system to enter an automatic control mode;

[0084] Turn on the fan to drive the gas flow speed in the air duct to reach the set speed, that is, simulate the stratospheric airflow environment;

[0085] Turn on the infrared heating system, heat the infrared simulation board 203-1 through the heating rod 203-6 to reach a temperature corresponding to the preset solar radiation heat flux density in the stratosphere, and set the temperature of the infrared simulation board 203-1 to enter the automatic control mode;

[0086] Turn on the power of the radio frequency device 301, turn on the radio frequency load, keep the radio frequency load working continuously for a predetermined time, and regularly record the data of each temperature sensor in the radio frequency device 301 during the continuous working of the radio frequency load;

[0087] After the test is finished, the power of the RF load, the heating rod 203 - 6 and the RF device 301 is turned off, the fan is stopped, the environment in the vacuum container 102 is restored to the ground environment state, and the RF device 301 is taken out.

[0088] Furthermore, when testing the working status of the radio frequency device 301, the pressure environment, temperature environment, airflow environment, and infrared radiation heat flow of the simulation system can also be adjusted to simulate different stratospheric environments to continuously test the working status of the radio frequency device 301, and record the data of each temperature sensor in the radio frequency device 301.

[0089] By directly testing the actual working state of the radio frequency device 301 in the ground stratospheric environment simulation system, the temperature data of each part of the radio frequency device 301 during operation is obtained. By analyzing these temperature data, it is possible to analyze whether the design of the radio frequency device 301 meets the requirements, find design problems and make targeted optimization and improvements.

[0090] It can be seen from the above embodiments that the present application provides an environmental simulation system for testing radio frequency equipment of high-altitude unmanned aerial vehicles, by arranging a coaxial cylindrical heat sink 101 in a vacuum container 102, and arranging a coaxial cylindrical structure 203-7 in the cylindrical heat sink 101, to form an inner air duct and an outer air duct, and the inner air duct and the outer air duct are connected to form an annular recirculation air duct that allows airflow to circulate, thereby greatly reducing the occupied space of the environmental simulation system; by designing a fan for generating airflow and a rectifier and a flow field for adjusting the airflow in the inner air duct The turbulence reduction net 202-3 forms a stable and continuous airflow in the wind duct to simulate the stratospheric airflow environment; by designing a structurally integrated wave-transparent plate 203-2 on the cylindrical structure 203-7, and arranging a wave-absorbing device 203-3 in the outer wind duct corresponding to the wave-transparent plate 203-2, the influence of microwaves on the stability of the airflow field in the wind duct when the radio frequency device 301 is running is eliminated, so that the radio frequency device 301 can be kept running continuously during actual testing; by designing a wave-absorbing device 203-3 on the cylindrical structure 203-7 that is structurally integrated with the cylindrical structure 203-7 The infrared simulation board 203-1 is provided with a heating rod 203-6 in the infrared simulation board 203-1. The infrared heating control system can control the infrared simulation board 203-1 to generate infrared radiation heat flux, which is equivalent to simulating the solar radiation heat flux, so that when the actual operation of the radio frequency device 301 is maintained, the radio frequency device 301 can also be subjected to a thermal test of simulating the solar radiation heat flux equivalently without affecting the airflow field, thereby solving the problem in the prior art that the structure for heating the radio frequency device 301 affects the airflow field and the thermal test cannot be carried out. The pressure control system is used to simulate the stratospheric pressure environment in the vacuum container 102, and the heat sink temperature control system is used to control the cylindrical heat sink 101 to simulate the stratospheric temperature environment in the vacuum container 102, so that the stratospheric temperature, pressure, airflow and solar radiation environment can be stably simulated, thereby providing an in-situ test simulated stratospheric environment for testing the actual operation state of the UAV radio frequency device 301 on the ground, thereby solving the problem in the prior art that the actual operation state of the UAV radio frequency device 301 cannot be directly tested in the stratospheric environment.

[0091] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. An environmental simulation system for testing radio frequency equipment of high-altitude unmanned aerial vehicles, characterized in that: The environmental simulation system comprises: A vacuum container, wherein the vacuum container is connected to a pressure control system for simulating a stratospheric pressure environment; A cylindrical heat sink is arranged inside the vacuum container and connected to a heat sink temperature control system for simulating a stratospheric temperature environment; A cylindrical structure is arranged inside the cylindrical heat sink; an outer air duct is formed between the outer wall of the cylindrical structure and the inner wall of the cylindrical heat sink, an inner air duct is arranged inside the cylindrical structure, the outer air duct is connected with the inner air duct to form an annular recirculation air duct for simulating a stratospheric air flow environment; the inner air duct is provided with a power device for simulating a stratospheric air flow environment; a radio frequency device to be tested is installed inside the inner air duct; A microwave absorption module, arranged in the cylindrical heat sink corresponding to the radio frequency device, and used for absorbing the microwave signal generated by the radio frequency device; The heat flow simulation module is arranged on the cylindrical structure corresponding to the radio frequency device, and is used to generate infrared radiation heat flow to simulate solar radiation heat flow to radiate and heat the radio frequency device.

2. The environmental simulation system for high-altitude unmanned aerial vehicle radio frequency equipment testing according to claim 1 is characterized in that: The microwave absorption module comprises: A wave-transparent plate, corresponding to the radio frequency device, is connected to the cylindrical structure in a form with its inner wall flush with the inner wall of the cylindrical structure, and can transmit the microwave signal generated by the radio frequency device to the external air duct without affecting the air flow field; The absorbing device is arranged in the external wind duct and includes a first absorbing plate coaxial with the cylindrical structure. A side of the first absorbing plate relatively close to the radio frequency device is connected to a plurality of second absorbing plates parallel to each other, and the other end of the second absorbing plate is close to the cylindrical structure.

3. The environmental simulation system for high-altitude UAV radio frequency equipment testing according to claim 1 is characterized in that: The thermal flow simulation module includes: An infrared simulation board, corresponding to the radio frequency device, is connected to the cylindrical structure, and its inner wall is flush with the inner wall of the cylindrical structure; A heating rod is arranged in the infrared simulation board along the circumference of the cylindrical structure; A heat insulation board, used to connect the infrared simulation board and the cylindrical structure; The infrared heating system is used to control the heating rod to adjust the temperature of the infrared simulation board to generate infrared radiation heat flux to simulate the solar radiation heat flux.

4. The environmental simulation system for high-altitude unmanned aerial vehicle radio frequency equipment testing according to claim 3 is characterized in that: The equivalent heat flux simulation method is used to simulate the solar radiation heat flux.

5. The environmental simulation system for high-altitude unmanned aerial vehicle radio frequency equipment testing according to claim 2 is characterized in that: The second wave absorbing plate is a flat plate structure, and the flat plate surface is parallel to the axis of the cylindrical structure.

6. The environmental simulation system for high-altitude unmanned aerial vehicle radio frequency equipment testing according to claim 2 is characterized in that: The wave-transmitting plate is made of polyimide; and the wave-absorbing device is made of silicon carbide or carbon foam.

7. The environmental simulation system for high-altitude unmanned aerial vehicle radio frequency equipment testing according to claim 1 is characterized in that: A rectifier and a turbulence reduction net for stabilizing the airflow field are sequentially arranged inside the inner air duct along the airflow direction; the rectifier includes a first honeycomb rectifier and a second honeycomb rectifier sequentially arranged along the airflow direction.

8. The environmental simulation system for high-altitude unmanned aerial vehicle radio frequency equipment testing according to claim 1 is characterized in that: The cylindrical heat sink is a tube-fin type or honeycomb air expansion plate type heat exchange structure, which is divided into a plurality of independently temperature-controllable areas along the airflow direction and respectively connected to the cylindrical heat sink temperature control system.

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