An outer vacuum acquisition and magnetic shield device for hydrogen atomic clock ground testing

Abstract

The application discloses an outer vacuum obtaining and magnetic shielding device for ground testing of a hydrogen atomic clock, comprising an outer vacuum preparation mechanism, wherein the outer vacuum preparation mechanism comprises a two-stage vacuum pump set, the two-stage vacuum pump set comprises a rotary vane molecular pump and a diaphragm oil-free mechanical pump, the two-stage vacuum pump set further comprises a vacuum gauge, a magnetic shielding cover, a pipeline, a vacuum valve one, a vacuum valve two and a magnetometer; the molecular pump and the mechanical pump are connected in series, and the mechanical pump serves as a front-stage pump. The application integrates zero magnetic treatment and environment control functions on the basis of a traditional vacuum pump set, is suitable for spacecraft assembly testing environment, meets severe testing conditions of the hydrogen atomic clock, is convenient to maintain, is suitable for transportation, can realize real-time measurement and control of vacuum degree and magnetic intensity, can realize rapid pressure relief testing of the hydrogen atomic clock in the device, verifies performance indexes of the hydrogen atomic clock under extreme environment, and is a necessary device for ground testing of next-generation spaceborne precise time and frequency instruments.

Description

Technical Field

[0001] This invention relates to the field of spacecraft testing technology, and in particular to an external vacuum acquisition and magnetic shielding device for ground testing of hydrogen atomic clocks. Background Technology

[0002] As a core component of navigation satellite payload systems, hydrogen atomic clocks have specific environmental requirements during on-orbit and ground operation. The main environmental indicators affecting their performance are: ambient vacuum level, temperature change rate, and magnetic field strength rate. A typical spaceborne hydrogen atomic clock is a passive hydrogen atomic clock (referred to as a hydrogen clock). The main body of the hydrogen clock consists of a circuit section and a physical section. The upper part is the physical section, and the lower part is the circuit system, connected by a frame structure. When the physical section achieves its design stability, its sensitivity to temperature changes is on the order of 10E-13℃, and its sensitivity to magnetic fields is on the order of 10E-14T. Such high environmental sensitivity must be achieved through multi-level isolation and shielding. Therefore, the physical section of the hydrogen clock needs to implement multi-level vacuum cavities, and the physical section and the circuit system as a whole require multi-level magnetic shielding measures.

[0003] The outermost layer of the multi-stage vacuum chamber surrounding the physical components of the hydrogen clock is referred to as the "outer vacuum." When operating in the Earth's surface environment, the outer vacuum provides a primary vacuum and insulation environment. The outer vacuum is equipped with vacuum valves, which are always closed. When operating in orbit, the hydrogen clock's outer vacuum must remain connected to the satellite's external environment. Vacuum pump units are required to provide the outer vacuum environment during satellite ground testing.

[0004] Furthermore, as a ground-based testing indicator, it is necessary to determine at what level of external vacuum the long-term time-frequency stability of the hydrogen clock begins to be affected, requiring the vacuum pump assembly to be equipped with a vacuum gauge. The magnetic field generated during the operation of the pump assembly and vacuum gauge also has an adverse effect on the testing; therefore, the testing process should ensure a near-background geomagnetic environment, necessitating magnetic measurements and magnetic shielding measures.

[0005] This invention patent uses a two-stage series vacuum pump group as the core, supplemented by necessary pipelines, valves, as well as vacuum measurement, magnetic measurement and magnetic shielding measures, to realize a device that can provide the vacuum and magnetic environment required for the operation of a hydrogen clock on the ground, and realize the simulated on-orbit performance test conditions of the hydrogen clock on the satellite. Summary of the Invention

[0006] The purpose of this invention is to provide an external vacuum acquisition and magnetic shielding device for ground testing of hydrogen atomic clocks in order to solve the above-mentioned problems.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An external vacuum acquisition and magnetic shielding device for ground testing of a hydrogen atomic clock includes an external vacuum preparation mechanism, which includes a two-stage vacuum pump group, which includes a rotary vane molecular pump and a diaphragm oil-free mechanical pump. The two-stage vacuum pump group also includes a vacuum gauge, a magnetic shield, a pipeline, a vacuum valve one, a vacuum valve two, and a magnetometer.

[0009] The molecular pump and the mechanical pump are connected in series, with the mechanical pump serving as a backing pump to provide a rough vacuum environment.

[0010] The molecular pump, acting as the main pump, provides a high-vacuum environment that meets the external vacuum requirements, based on the rough vacuum pumping of the backing pump.

[0011] Preferably, a hydrogen atomic clock is installed inside the magnetic shielding cover, the magnetic shielding cover covers the physical and circuit parts of the hydrogen atomic clock, and the inside of the hydrogen atomic clock is an external vacuum cavity.

[0012] Preferably, one end of the pipe is connected to the external vacuum chamber of the hydrogen atomic clock via vacuum valve one, and the other end of the pipe is connected to the inlet of the molecular pump via vacuum valve two.

[0013] Preferably, the vacuum gauge is used to measure the vacuum level of the external vacuum cavity of the hydrogen atomic clock.

[0014] Preferably, the magnetometer is equipped with at least two magnetically sensitive probes to measure the magnetic field strength during the operation of the ground equipment and the remanent magnetic field strength of the satellite near the hydrogen atomic clock during satellite testing.

[0015] Preferably, the hydrogen atomic clock test preparation process includes the following steps:

[0016] S1. Connect the pipeline and set vacuum valve one and vacuum valve two to open;

[0017] S2. Power on the device and read the vacuum gauge display value;

[0018] S3. Start the mechanical pump and begin working. The vacuum value will drop to the threshold at which the molecular pump can be turned on.

[0019] S4. Start the molecular pump to operate, the vacuum value drops, and the test requirements are met;

[0020] S5. Keep the molecular pump running for the specified time to remove adsorbed gas in the chamber;

[0021] S6. Read the magnetometer display value; it meets the test requirements.

[0022] S7. Satellite payload time and frequency testing begins; hydrogen atomic clock stability index is determined.

[0023] S8. After closing vacuum valve one and vacuum valve two, turn off the molecular pump switch;

[0024] S9. After the molecular pump operation indicator light goes out, turn off the mechanical pump and disconnect the power to the equipment.

[0025] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0026] 1. This application integrates zero-magnetic processing and environmental control functions on the basis of traditional vacuum pump groups, adapting to the spacecraft assembly and testing environment and meeting the stringent testing conditions of hydrogen atomic clocks; the system is easy to maintain and transport, and can realize real-time measurement and control of vacuum degree and magnetic intensity. The equipment in this application can realize rapid decompression test of the external vacuum of hydrogen atomic clocks, verifying the performance indicators of hydrogen atomic clocks under extreme environments; this equipment is a necessary device for ground testing of next-generation spaceborne precision time and frequency instruments. Attached Figure Description

[0027] Figure 1 A schematic diagram of the main structure of the external vacuum preparation mechanism provided according to an embodiment of the present invention is shown.

[0028] Legend:

[0029] 1. Satellite; 2. Hydrogen atomic clock; 3. Magnetic shield; 4. Vacuum valve one; 5. Magnetometer; 6. Mechanical pump; 7. Molecular pump; 8. Vacuum gauge; 9. Vacuum valve two; 10. Pipeline. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Please see Figure 1 The present invention provides a technical solution:

[0032] An external vacuum acquisition and magnetic shielding device for ground testing of a hydrogen atomic clock includes an external vacuum preparation mechanism, which includes a two-stage vacuum pump group, which includes a rotary vane molecular pump 7 and a diaphragm oil-free mechanical pump 6. The two-stage vacuum pump group also includes a vacuum gauge 8, a magnetic shield 3, a pipeline 10, a vacuum valve 4, a vacuum valve 9, and a magnetometer 5.

[0033] The equipment frame connects all the above parts to form a whole (except for magnetometer 5 and magnetic shield 3). Magnetometer 5 is a relatively independent device.

[0034] The molecular pump 7 and the mechanical pump 6 are connected in series, with the mechanical pump 6 serving as a backing pump to provide a rough vacuum environment.

[0035] The back pump must be oil-free and free of foreign matter, and its noise level must meet the general testing environment requirements for spacecraft; a diaphragm mechanical pump is preferred.

[0036] The molecular pump 7 serves as the main pump, providing a high-vacuum environment that meets the external vacuum requirements based on the rough vacuuming of the backing pump.

[0037] To ensure that the external vacuum index of the hydrogen atomic clock 2 is maintained, the molecular pump 7 should run continuously for a specified time to remove the adsorption of gas in the cavity;

[0038] To ensure the safety of the equipment and the testing process, the mechanical pump 6 can only be turned off after the indicator light of the molecular pump 7 is turned off.

[0039] Specifically, such as Figure 1 As shown, a hydrogen atomic clock 2 is installed inside the magnetic shielding cover 3. The magnetic shielding cover 3 covers the physical and circuit parts of the hydrogen atomic clock 2, and the inside of the hydrogen atomic clock 2 is an external vacuum cavity.

[0040] One end of pipe 10 is connected to the external vacuum chamber of hydrogen atomic clock 2 through vacuum valve 14, and the other end of pipe 10 is connected to the inlet of molecular pump 7 through vacuum valve 29.

[0041] Vacuum valve 4 and vacuum valve 9 are responsible for switching pipeline 10 on and off; the length and volume of pipeline 10 affect the achievement of the target indicators of this scheme; pipeline 10 that is too short will cause magnetic interference, and pipeline 10 that is too long will affect the vacuum index during the test.

[0042] Vacuum valve 4 uses non-magnetic materials and parts;

[0043] Vacuum gauge 8 is used to measure the vacuum level of the external vacuum cavity of hydrogen atomic clock 2. The measurement accuracy of vacuum gauge 8 is better than 30% of the reading.

[0044] The magnetometer 5 is equipped with at least two magnetically sensitive probes, which measure the magnetic field strength when the ground equipment is running and the remanent magnetic field strength of the satellite body 1 near the hydrogen atomic clock 2 during satellite testing.

[0045] The use of magnetometer 5 involves two steps:

[0046] The equipment is powered on and then subjected to on-board measurements before testing. The equipment placement and orientation are determined based on the on-board measurement results. The satellite payload time-frequency test is then initiated based on the on-board measurement results.

[0047] The preparation process for the hydrogen atom clock 2 test includes the following steps:

[0048] S1, pipe 10 connection, set vacuum valve 4 and vacuum valve 9 to be open;

[0049] S2. Power on the device and read the value displayed on vacuum gauge 8;

[0050] S3. Start mechanical pump 6 to work, and reduce the vacuum value to the threshold that allows molecular pump 7 to be turned on;

[0051] S4. Start the molecular pump 7 to operate, the vacuum value drops, and the test requirements are met;

[0052] S5. Keep the molecular pump 7 running for a specified time to remove adsorbed gas in the chamber.

[0053] S6. Read the value displayed on magnetometer 5, which meets the test requirements;

[0054] S7. Satellite payload time and frequency testing begins; stability index of hydrogen atomic clock 2 is determined.

[0055] S8. After closing vacuum valve 4 and vacuum valve 9, turn off the switch of molecular pump 7.

[0056] After the indicator light for S9 and molecular pump 7 goes out, turn off mechanical pump 6 and disconnect the power to the equipment.

[0057] The equipment in this application is portable and adaptable to use in different areas such as manufacturing, testing, and pre-launch. This application mainly includes the integration of zero magnetic treatment and pollution and noise environment control functions on the basis of traditional vacuum pump sets. It has the ability to prepare external vacuum chambers, achieving a vacuum index on the order of 1×10E-3Pa. The magnetic field strength of the equipment during operation and the remanent magnetic field strength of satellite 1 near hydrogen atomic clock 2 during satellite testing do not exceed 10% of the ambient background magnetic field.

[0058] The above description of the embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An external vacuum acquisition and magnetic shielding device for ground testing of a hydrogen atomic clock, comprising an external vacuum preparation mechanism, characterized in that, The external vacuum preparation mechanism includes a two-stage vacuum pump group, which includes a rotary vane molecular pump (7) and a diaphragm oil-free mechanical pump (6). The two-stage vacuum pump group also includes a vacuum gauge (8), a magnetic shield (3), a pipeline (10), a vacuum valve one (4), a vacuum valve two (9), and a magnetometer (5). The rotary vane molecular pump (7) and the diaphragm oilless mechanical pump (6) are connected in series, and the diaphragm oilless mechanical pump (6) serves as a backing pump to provide a rough vacuum environment. The rotary vane molecular pump (7) serves as the main pump, providing a high vacuum environment that meets the external vacuum requirements based on the rough vacuuming of the back pump. The magnetic shield (3) contains a hydrogen atomic clock (2), which covers the physical and circuit parts of the hydrogen atomic clock (2). The interior of the hydrogen atomic clock (2) is an external vacuum cavity. One end of the pipe (10) is connected to the external vacuum chamber of the hydrogen atomic clock (2) through vacuum valve one (4), and the other end of the pipe (10) is connected to the inlet of the rotary vane molecular pump (7) through vacuum valve two (9); The vacuum gauge (8) is used to measure the vacuum level of the external vacuum cavity of the hydrogen atomic clock (2); The magnetometer (5) is equipped with at least two magnetically sensitive probes, which measure the magnetic field strength when the ground equipment is running and the remanent magnetic field strength of the satellite body (1) near the hydrogen atomic clock (2) during satellite testing.

2. The external vacuum acquisition and magnetic shielding device for ground testing of a hydrogen atomic clock according to claim 1, characterized in that, The test preparation process for the hydrogen atomic clock (2) includes the following steps: S1, pipe (10) connection, set vacuum valve one (4) and vacuum valve two (9) to open; S2. Power on the device and read the value displayed on the vacuum gauge (8); S3. Start the diaphragm oilless mechanical pump (6) to start working, and reduce the vacuum value to the threshold that allows the rotary vane molecular pump (7) to be turned on; S4. Start the rotary vane molecular pump (7) to operate, the vacuum value drops, and the test requirements are met; S5. Keep the rotary vane molecular pump (7) running for a specified time to remove the adsorption of gas in the chamber; S6. Read the value displayed on the magnetometer (5) to ensure it meets the test requirements; S7. Satellite payload time and frequency test begins, hydrogen atomic clock (2) stability index is read; S8. After closing vacuum valve one (4) and vacuum valve two (9), turn off the rotary vane molecular pump (7) switch; S9. After the indicator light of the rotary vane molecular pump (7) goes out, shut down the diaphragm oilless mechanical pump (6) and disconnect the power to the equipment.

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