Microwave-laser hybrid link radio star calibration equipment and method applicable to deep space exploration

Abstract

The present invention discloses a radio star calibration device and method for a microwave-laser hybrid link applicable to deep space exploration, which relates to the field of aerospace deep space exploration. Radio star calibration is used to complete the pointing calibration of the microwave-laser hybrid link of a large-aperture antenna in deep space. First, the pointing calibration of the microwave link is performed. After the microwave link stably tracks, the laser link performs fine tracking and completes the pointing calibration of the laser link, forming respective pointing error correction coefficients to achieve real-time correction of the antenna pointing. The microwave-laser link hybrid radio star calibration is not restricted by distance and geographical conditions and can perform real-time calibration; the beam of the laser link is narrower than that of the microwave link, and the calibration accuracy is higher, which can improve the system pointing accuracy and the optoelectronic axis consistency accuracy. The design of the present invention is simple, has strong generalization, low implementation difficulty, and is convenient for implementation and popularization.

Description

Technical Field

[0001] The present invention relates to the field of aerospace deep space exploration, and particularly to a radio star calibration device and method for a microwave laser hybrid link applicable to deep space exploration, which can be applicable to the pointing calibration of a microwave laser hybrid link of a super-large aperture antenna in deep space. Background Art

[0002] In the field of aerospace deep space exploration, the microwave laser integrated measurement and control communication technology can solve the bottleneck problem of large-capacity data transmission and is an important research direction for future deep space exploration. The pointing calibration of a microwave laser composite antenna based on a large aperture antenna in deep space is one of the key technologies of the microwave laser integrated measurement and control communication technology, which affects the consistency of the electrical axis of the microwave link and the optical axis of the laser link, as well as the stability of the microwave link tracking and the laser link tracking. It is necessary to study the pointing calibration technology of the microwave laser composite antenna of the large aperture antenna in deep space. For large aperture antennas in deep space, the far-field distance in the Ka band is relatively large, and it is not suitable for the calibration method of fixed beacon; the calibration using an earth satellite is restricted by many factors such as resources and costs; generally, the radio star calibration method is adopted. Summary of the Invention

[0003] In view of this, the present invention provides a radio star calibration device and method for a microwave laser hybrid link applicable to deep space exploration. The technical problem to be solved is the calibration problem of the pointing of the microwave link and the laser link of a large aperture antenna in deep space, which can realize the accuracy of the pointing of the microwave link and the laser link and can perform measurement and control communication with the same target satellite. The present invention has the characteristics of high calibration accuracy and high stability.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A radio star calibration device for a microwave laser hybrid link applicable to deep space exploration includes a microwave link, a laser link, and a calibration computer; the microwave link includes a Ka microwave antenna, a Ka channel device, a power meter, and a servo device; the laser link includes a two-dimensional galvanometer of a laser antenna, a fine tracking detector, a spot centroid extraction and deviation calculation unit, a fine tracking controller, and a galvanometer driver;

[0006] The Ka microwave antenna is used to receive space microwave signals and convert them into electrical signals for transmission to the Ka channel device;

[0007] The Ka channel device is used to convert the received electrical signals into 300M intermediate frequency signals for transmission to the power meter;

[0008] The power meter is used to detect the energy of the 300M intermediate frequency signal and transmit the energy value to the calibration computer;

[0009] The two-dimensional galvanometer of the laser antenna is used to receive space laser signals and transmit the space laser signals to the fine tracking detector;

[0010] The fine tracking detector is used to collect optical images from the space laser signal and transmit them to the spot centroid extraction and deviation calculation unit;

[0011] The spot centroid extraction and deviation calculation unit is used to extract the spot centroid position and the deviation amount, and transmit them to the fine tracking controller and the calibration computer;

[0012] The fine tracking controller is used to convert the deviation information provided by the spot centroid extraction and deviation calculation unit into control information and transmit it to the galvanometer driver;

[0013] The galvanometer driver is used to control the two-dimensional galvanometer of the laser antenna to move according to the control information provided by the fine tracking controller and track the incident light;

[0014] The calibration computer is used to form microwave link pointing deviation information according to the energy value provided by the power meter; and perform coordinate transformation according to the spot centroid position and the deviation amount provided by the spot centroid extraction and deviation calculation unit to form laser link pointing deviation information;

[0015] The servo device is used to receive the microwave link pointing deviation information and the laser link pointing deviation information of the calibration computer, and control the Ka microwave antenna to rotate and point to the target.

[0016] A radio star calibration method for a microwave-laser hybrid link applicable to deep space exploration implemented based on the above device includes the following steps:

[0017] Step 1, perform radio star calibration on the microwave link: The space microwave signal passes through the Ka microwave antenna, the Ka channel device and the power meter in sequence to obtain the radio star energy. The calibration computer calculates the pointing deviation according to the radio star energy size, controls the servo device to adjust the pointing of the Ka microwave antenna to make the received radio star energy the largest, and records the actual pointing position of the Ka microwave antenna, including the azimuth angle and the elevation angle;

[0018] Step 2, the calibration computer calculates the theoretical position of the radio star according to the ephemeris file, compares it with the actual pointing position of the Ka microwave antenna, calculates the microwave antenna error correction parameter, and stores it in the microwave pointing error correction file;

[0019] Step 3, after the microwave link pointing is stable, perform fine tracking on the laser link: The space laser signal passes through the two-dimensional galvanometer of the laser antenna, the fine tracking detector and the spot centroid extraction and deviation calculation unit in sequence to obtain the spot position deviation. The fine tracking controller drives the two-dimensional galvanometer of the laser antenna to track the laser signal according to the spot position deviation through the galvanometer driver;

[0020] Step 4: The calibration computer calculates the deviation from the image center position based on the spot position, performs coordinate system conversion, and calculates the laser antenna error correction parameters according to the azimuth and elevation angle amounts corresponding to each pixel of the image, and stores them in the laser pointing error correction file.

[0021] Step 5: Repeat Steps 1 - 4 for radio stars at different positions to form omnidirectional microwave and laser pointing error correction parameters.

[0022] Step 6: During angle tracking, first use the microwave link to perform angle tracking on the satellite target. After the microwave link tracking is stable, guide the laser link to complete the tracking. When the laser link completes the tracking, switch to the laser link to track and guide the microwave link to track.

[0023] The present invention has the following advantages:

[0024] (1) The radio star calibration of the microwave - laser link hybrid is not restricted by distance and geographical conditions and can be calibrated in real time.

[0025] (2) The beam of the laser link is narrower than that of the microwave link, and the calibration accuracy is higher, which can improve the system pointing accuracy and the accuracy of the optoelectronic axis consistency.

[0026] (3) The design of the present invention is simple, with strong generalization, low implementation difficulty, and is convenient for implementation and promotion. Description of the Drawings

[0027] Figure 1 is the composition diagram of the microwave - laser hybrid link calibration device of the present invention.

[0028] Figure 2 is the working flow chart of the radio star calibration method for the microwave - laser hybrid link of the present invention. Detailed Embodiment

[0029] The following further describes the present invention in conjunction with the attached Figure 1-2 drawings and specific examples.

[0030] The composition of a microwave - laser hybrid link radio star calibration device applicable to deep - space exploration is referred to Figure 1 , and includes a microwave link, a laser link, and a calibration computer 9; the microwave link includes a Ka microwave antenna 1, a Ka channel device 2, a power meter 3, and a servo device 10; the laser link includes a two - dimensional galvanometer 4 for the laser antenna, a fine - tracking detector 5, a spot centroid extraction and deviation calculation unit 6, a fine - tracking controller 7, and a galvanometer driver 8.

[0031] The Ka microwave antenna 1 is used to receive space microwave signals and convert them into electrical signals for transmission to the Ka channel device 2.

[0032] The Ka channel device 2 is used to convert the received electrical signals into 300M intermediate - frequency signals for transmission to the power meter 3.

[0033] The power meter 3 is used to detect the energy of the 300M intermediate frequency signal and transmit the energy value to the calibration computer 9;

[0034] The two-dimensional galvanometer 4 of the laser antenna is used to receive the spatial laser signal and transmit the spatial laser signal to the fine tracking detector 5;

[0035] The fine tracking detector 5 is used to collect the optical image from the spatial laser signal and transmit it to the spot centroid extraction and deviation calculation unit 6;

[0036] The spot centroid extraction and deviation calculation unit 6 is used to extract the spot centroid position and the deviation amount and transmit them to the fine tracking controller 7 and the calibration computer 9; [[ID=I3]]

[0037] The fine tracking controller 7 is used to convert the deviation information provided by the spot centroid extraction and deviation calculation unit 6 into control information and transmit it to the galvanometer driver 8;

[0038] The galvanometer driver 8 is used to control the movement of the two-dimensional galvanometer 4 of the laser antenna to track the incident light according to the control information provided by the fine tracking controller 7;

[0039] The calibration computer 9 is used to form the pointing deviation information of the microwave link according to the magnitude of the energy value provided by the power meter 3; and perform coordinate transformation according to the spot centroid position and the deviation amount provided by the spot centroid extraction and deviation calculation unit 6 to form the pointing deviation information of the laser link;

[0040] The servo device 10 is used to receive the pointing deviation information of the microwave link and the laser link from the calibration computer 9 and control the Ka microwave antenna 1 to rotate and point to the target.

[0041] A radio star calibration method for a microwave-laser hybrid link applicable to deep space exploration implemented based on the above devices, refer to Figure 2 , including the following steps:

[0042] Step 1, radio star calibration of the microwave link: The spatial microwave signal passes through the Ka microwave antenna, the Ka channel device and the power meter in sequence to obtain the radio star energy. The calibration computer calculates the pointing deviation according to the magnitude of the radio star energy, controls the servo device to adjust the pointing of the Ka microwave antenna to make the received radio star energy maximum, and records the actual pointing position of the Ka microwave antenna, including the azimuth angle and the elevation angle;

[0043] Due to the influence of gravity, atmospheric refraction, temperature, etc., there is a certain error between the actual pointing of the microwave link and the target position, and generally calibration correction is required.

[0044] Step 2: The calibration computer calculates the theoretical position of the radio star based on the ephemeris file, compares it with the actual pointing position of the Ka microwave antenna, calculates the error correction parameters of the microwave antenna, and stores them in the microwave pointing error correction file.

[0045] The obtained microwave pointing error correction data is provided by the calibration computer to the servo device, and the servo device uses these error data to correct the antenna in real time.

[0046] Step 3: After the microwave link points stably, the laser link performs fine tracking: The spatial laser signal passes through the two-dimensional galvanometer of the laser antenna, the fine tracking detector, and the spot centroid extraction and deviation calculation unit in sequence to obtain the spot position deviation. The fine tracking controller drives the two-dimensional galvanometer of the laser antenna to track the laser signal through the galvanometer driver according to the spot position deviation.

[0047] When the antenna is installed, the electrical axis of the Ka microwave antenna and the optical axis of the two-dimensional galvanometer of the laser antenna are made to point in the same direction. When the Ka microwave antenna points at the radio star, theoretically, the radio star is within the fine tracking capture range of the two-dimensional galvanometer of the laser antenna. During installation, the pointing consistency between the Ka microwave antenna and the two-dimensional galvanometer of the laser antenna is required to be less than 0.002 degrees. After the Ka microwave antenna tracks stably, the two-dimensional galvanometer of the laser antenna can perform fine tracking. The fine tracking uses an orthogonal two-dimensional galvanometer as the optical device for controlling the beam pointing, and the fine tracking detector is a CMOS camera.

[0048] Step 4: The calibration computer calculates the deviation amount between the spot position and the image center position, performs coordinate transformation, and calculates the laser antenna error correction parameters according to the azimuth and elevation angle amounts corresponding to each pixel of the image, and stores them in the laser pointing error correction file.

[0049] The CMOS image data is transmitted to a signal processing chip, such as a DSP chip, to complete the extraction of the spot centroid and deviation information, and the spot centroid and deviation data are transmitted to the fine tracking controller through the peripheral interface circuit. The spot image data is transmitted to the calibration computer for real-time display. Since the beam of the laser link is narrower than that of the microwave link and the calibration accuracy is higher, after obtaining the pointing correction data of the laser beam, the optoelectronic axis consistency accuracy and the pointing calibration accuracy of the entire system can be improved.

[0050] Step 5: Repeat Steps 1 - 4 for radio stars at different positions to form omnidirectional microwave and laser pointing error correction parameters.

[0051] Step 6: During angle tracking, first use the microwave link to perform angle tracking on the satellite target. After the microwave link tracks stably, it guides the laser link to complete the tracking. When the laser link completes the tracking, switch to the laser link to track and guide the microwave link to track.

[0052] During the angle tracking process, on the basis of correcting the angle tracking pointing by using the calibration results of the microwave link, the calibration results of the laser link are further used to correct the angle tracking pointing. Finally, the optical center of the radio star is used as the calibrated pointing reference. Since the calibration accuracy of the laser link is higher than that of the microwave link, the tracking accuracy of the corrected system can reach 10 urad.

[0053] In summary, the present invention uses radio star calibration to complete the pointing calibration of the microwave-laser hybrid link. The microwave-laser link hybrid radio star calibration is not restricted by distance and geographical conditions and can be calibrated in real time; the beam of the laser link is narrower than that of the microwave link, and the calibration accuracy is higher, which can improve the system pointing accuracy and the accuracy of the electro-optical axis consistency. The design of the present invention is simple, has strong generalization, low implementation difficulty, and is convenient for implementation and popularization.

Claims

1. A radio star calibration device for microwave-laser hybrid links applicable to deep space exploration, characterized in that, It includes a microwave link, a laser link and a calibration computer (9); the microwave link includes a Ka microwave antenna (1), a Ka channel device (2), a power meter (3) and a servo device (10); the laser link includes a two-dimensional galvanometer of the laser antenna (4), a fine tracking detector (5), a spot centroid extraction and deviation calculation unit (6), a fine tracking controller (7) and a galvanometer driver (8); The Ka microwave antenna (1) is used to receive spatial microwave signals and convert them into electrical signals for transmission to the Ka channel device (2); The Ka channel device (2) is used to convert the received electrical signals into 300M intermediate frequency signals for transmission to the power meter (3); The power meter (3) is used to detect the energy of the 300M intermediate frequency signals and transmit the energy value to the calibration computer (9); The two-dimensional galvanometer of the laser antenna (4) is used to receive spatial laser signals and transmit the spatial laser signals to the fine tracking detector (5); The fine tracking detector (5) is used to collect optical images from the spatial laser signals and transmit them to the spot centroid extraction and deviation calculation unit (6); The spot centroid extraction and deviation calculation unit (6) is used to extract the spot centroid position and the deviation amount and transmit them to the fine tracking controller (7) and the calibration computer (9); The fine tracking controller (7) is used to convert the deviation information provided by the spot centroid extraction and deviation calculation unit (6) into control information for transmission to the galvanometer driver (8); The galvanometer driver (8) is used to control the movement of the two-dimensional galvanometer of the laser antenna (4) to track the incident light according to the control information provided by the fine tracking controller (7); The calibration computer (9) is used to form microwave link pointing deviation information based on the magnitude of the energy value provided by the power meter (3); and perform coordinate transformation based on the spot centroid position and the deviation amount provided by the spot centroid extraction and deviation calculation unit (6) to form laser link pointing deviation information; The servo device (10) is used to receive the microwave link pointing deviation information and the laser link pointing deviation information of the calibration computer (9) and control the rotation of the Ka microwave antenna (1) to point to the target.

2. A radio star calibration method for a microwave-laser hybrid link applicable to deep space exploration implemented based on the device described in claim 1, characterized in that, It includes the following steps: Step 1, the microwave link performs radio star calibration: the spatial microwave signals pass through the Ka microwave antenna, the Ka channel device and the power meter in sequence to obtain the radio star energy. The calibration computer calculates the pointing deviation based on the magnitude of the radio star energy, controls the servo device to adjust the pointing of the Ka microwave antenna to make the received radio star energy maximum, and records the actual pointing position of the Ka microwave antenna, including the azimuth angle and the elevation angle; Step 2, the calibration computer calculates the theoretical position of the radio star according to the ephemeris file, compares it with the actual pointing position of the Ka microwave antenna, calculates the microwave antenna error correction parameters, and stores them in the microwave pointing error correction file; Step 3, after the microwave link pointing is stable, the laser link performs fine tracking: the spatial laser signals pass through the two-dimensional galvanometer of the laser antenna, the fine tracking detector and the spot centroid extraction and deviation calculation unit in sequence to obtain the spot position deviation. The fine tracking controller drives the two-dimensional galvanometer of the laser antenna to track the laser signal through the galvanometer driver according to the spot position deviation; Step 4: The calibration computer calculates the deviation amount from the image center position based on the spot position, performs coordinate system conversion, and calculates the laser antenna error correction parameters according to the azimuth and elevation angle amounts corresponding to each pixel of the image, and stores them in the laser pointing error correction file. Step 5: Repeat Steps 1-4 for radio stars at different positions to form omnidirectional microwave and laser pointing error correction parameters. Step 6: During angle tracking, first use the microwave link to perform angle tracking on the satellite target. After the microwave link tracking is stable, guide the laser link to complete the tracking. When the laser link completes the tracking, switch to the laser link to track and guide the microwave link to track.

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