A Ka-band automatic tracking system applied to satellite communication systems

Abstract

The present invention discloses a Ka-band automatic tracking system applied to a satellite communication system, which includes a bracket. A servo turntable is installed on the bracket, and a monopulse tracking receiver is installed on the servo turntable. The servo turntable and the monopulse tracking receiver are connected by a radio frequency cable. A vertical rod is arranged on the servo turntable, and a connecting component is hinged to the top end of the vertical rod. A box body with openings at the top and both sides is detachably installed on the connecting component. A multimode feed module and an orthomode coupler are installed between the two side plates of the box body. A ring focus reflector antenna and a GPS antenna mechanism are installed on the outside of one side plate of the box body, and a radio frequency front end is installed on the outside of the other side plate. The present invention has the monopulse self-tracking ability, can realize real-time communication with a mobile satellite, and achieve the stability of communication signals.

Description

Technical Field

[0001] The present invention belongs to the field of satellite communication ground station equipment, and particularly relates to a Ka-band automatic tracking system applied to a satellite communication system. Background Art

[0002] Satellite communication has always been one of the important communication means in the communication field. Satellite communication ground station equipment integrates technologies such as antenna technology, communication technology, automatic control technology, signal processing technology, and structural design technology. Satellite communication ground station equipment can provide secure and reliable voice, fax, image, video, data communication, and IP services, and can be widely used in fields such as battlefield military communication, mobile command, emergency communication support, live broadcast of competition scenes, and listening to radio and television programs.

[0003] Currently, common Ka-band ground station equipment can only communicate with geostationary satellites and does not have the ability of self-tracking, making it difficult to achieve communication with medium and low-earth orbit mobile satellites. Summary of the Invention

[0004] The purpose of the present invention is to provide a Ka-band automatic tracking system applied to a satellite communication system, which has the ability of monopulse self-tracking, can achieve real-time communication with mobile satellites, and realize the stability of communication signals.

[0005] The present invention adopts the following technical solutions: A Ka-band automatic tracking system applied to a satellite communication system includes a bracket, on which a servo turntable is installed, and a monopulse tracking receiver is installed on the servo turntable. The servo turntable and the monopulse tracking receiver are connected by a radio frequency cable;

[0006] A vertical rod is provided on the servo turntable, and a connecting component is hinged at the top of the vertical rod. A box body with openings at the top and both sides is detachably installed on the connecting component;

[0007] A multimode feed module and an orthomode coupler are installed between the two side plates of the box body. A ring focus reflector antenna and a GPS antenna mechanism are installed outside one side plate of the box body, and a radio frequency front end is installed outside the other side plate;

[0008] The ring focus reflector antenna and the multimode feed module, and the multimode feed module and the orthomode coupler are both connected by waveguides. The multimode feed module and the radio frequency front end, and the radio frequency front end and the monopulse tracking receiver are both connected by radio frequency cables;

[0009] The servo turntable is used to adjust the orientation of the ring focus reflector antenna according to the azimuth error signal and elevation error signal output by the monopulse tracking receiver, so that the ring focus reflector antenna continuously tracks the satellite signal.

[0010] Preferably, the GPS antenna mechanism includes an antenna bracket. Two U-shaped openings are formed at the top of the antenna bracket. A folding tube is mounted on the U-shaped opening, and GPS antennas are mounted at both ends of the folding tube.

[0011] Preferably, the folding tube includes at least two hollow tubes, and adjacent hollow tubes are connected by a ferrule;

[0012] The ferrule includes a first snap ring and a second snap ring that are respectively sleeved on the ends of adjacent two hollow tubes. A pin shaft penetrates through one side of the first snap ring, and the second snap ring is sleeved on both ends of the pin shaft. The other sides of the first snap ring and the second snap ring are clamped.

[0013] Preferably, the connecting component includes two oppositely arranged ear plates. The two ear plates are respectively connected to both ends of the same rotating shaft, and the tops of the two ear plates are connected by a flat plate;

[0014] Convex edges extend upward on both sides of the flat plate, and sliding grooves are formed on the inner sides of the two convex edges;

[0015] Sliding blocks extend outward from both sides of the bottom plate of the box body. The sliding blocks have the same shape as the sliding grooves;

[0016] A fastening screw is mounted on each sliding groove.

[0017] Preferably, the cross-sectional shape of the sliding groove is a trapezoid with a smaller upper part and a larger lower part.

[0018] Preferably, the bracket includes a support platform. At least three turntable legs are connected to the side surface of the support platform. The connecting end of each turntable leg is higher than the supporting end, and an adjusting foot cup is mounted at the supporting end of each turntable leg.

[0019] Preferably, a vertical groove with a trapezoidal cross-section is formed on the side surface of the support platform. The lower bottom edge of the trapezoid is inside the groove and the upper bottom edge is on the surface of the groove; a fixing bolt is mounted on the inclined side of the vertical groove;

[0020] The shape of the connecting end of each turntable leg is the same as the shape of the vertical groove;

[0021] Each fixing bolt is used to abut against the connecting end of the turntable leg through its end to realize the fixation between the turntable leg and the support platform.

[0022] The beneficial effects of the present invention are as follows: the sum signal and the difference signal of the incoming wave signal are extracted by the multi-mode feed module, and the signal is converted from the Ka frequency to the intermediate frequency signal through the RF front end. Then, the azimuth error signal and the elevation error signal of the servo turntable are obtained through the monopulse tracking receiver. The servo turntable adjusts the steering of the ring focus reflector antenna according to this signal, so as to realize the real-time and uninterrupted communication between the device and the mobile satellite and achieve the stability of the communication signal. Description of the Drawings

[0023] Figure 1 Schematic diagram of the structure of a Ka - band automatic tracking system according to an embodiment of the present invention for a satellite communication system;

[0024] Figure 2 is Figure 1 Partial enlarged view of part A in

[0025] Figure 3 Principle block diagram of the RF front - end in an embodiment of the present invention.

[0026] Wherein: 1. Cassegrain reflector antenna; 2. Multimode feed module; 3. Orthomode coupler; 4. RF front - end; 5. Monopulse tracking receiver; 6. Servo turntable; 7. Turntable leg; 8. Folding mechanism; 9. GPS antenna; 10. Bracket; 11. Vertical rod; 12. Antenna bracket; 13. Ear plate; 14. Flat plate; 15. Flange; 16. Base plate; 17. Fastening screw. Specific embodiments

[0027] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] An embodiment of the present invention discloses a Ka - band automatic tracking system for a satellite communication system. As Figure 1 shown, it includes a bracket 10, on which a servo turntable 6 is installed. A monopulse tracking receiver 5 is installed on the servo turntable 6, and the servo turntable 6 and the monopulse tracking receiver 5 are connected by a RF cable. A vertical rod 11 is provided on the servo turntable 6. The top end of the vertical rod 11 is hinged with a connection component, and a box body with openings at the top and on both sides is detachably installed on the connection component. A multimode feed module 2 and an orthomode coupler 3 are installed between the two side plates of the box body. A Cassegrain reflector antenna 1 and a GPS antenna mechanism are installed outside one side plate of the box body, and a RF front - end 4 is installed outside the other side plate. The Cassegrain reflector antenna 1 and the multimode feed module 2, and the multimode feed module 2 and the orthomode coupler 3 are connected by waveguides. The multimode feed module 2 and the RF front - end 4, and the RF front - end 4 and the monopulse tracking receiver 5 are connected by RF cables. The servo turntable 6 is used to adjust the orientation of the Cassegrain reflector antenna 1 according to the azimuth error signal and elevation error signal output by the monopulse tracking receiver 5, so that the Cassegrain reflector antenna 1 continuously tracks the satellite signal.

[0029] The sum signal and difference signal of the incoming wave signal are extracted by the multimode feed module 2, and the signal is converted from the K - band to the intermediate - frequency signal through the RF front - end 4. Then, the azimuth error signal and elevation error signal of the servo turntable are obtained through the monopulse tracking receiver 5. The servo turntable adjusts the turning direction of the Cassegrain reflector antenna according to this signal, which can realize real - time and uninterrupted communication between the device and the moving satellite and ensure the stability of the communication signal.

[0030] Specifically, the ring focus reflector antenna 1 is used to receive high-frequency radio electromagnetic wave signals in the range of 17 - 20.2 GHz and transmit signals in the range of 27 - 32 GHz. The multimode feed module 2 is used to excite sum and difference signals. The orthomode coupler 3 is used to separate mutually orthogonal receiving signals in the range of 17 - 20.2 GHz and transmitting signals in the range of 27 - 32 GHz in the waveguide transmission line. The RF front-end 4 is used to amplify, frequency-convert, control, and filter the received 17 - 20.2 GHz signals and output two 70 MHz intermediate-frequency signals. The monopulse tracking receiver 5 is used to perform monopulse tracking on the 70 MHz signals. The servo turntable 6 is used to adjust the orientation of the ring focus reflector antenna 1 according to the azimuth error signal and elevation error signal output by the monopulse tracking receiver 5, so that the ring focus reflector antenna 1 continuously tracks satellite signals.

[0031] The main material of the ring focus reflector antenna 1 is carbon fiber. The antenna is composed of 8 antenna surfaces, and specific sorting is installed between the antenna surfaces. The antenna surfaces are spliced using buckles, latches, and locking devices. The antenna surfaces have the characteristics of light weight and high strength.

[0032] As Figure 2 shown, the connecting component includes two oppositely arranged ear plates 13. The two ear plates 13 are respectively connected to both ends of the same rotating shaft. The tops of the two ear plates 13 are connected by a flat plate 14; convex edges 15 extend upward (on the side opposite to the ear plates) on both sides of the flat plate 14, and sliding grooves are opened on the inner sides of the two convex edges 15; sliders extend outward from both sides of the bottom plate 16 of the box body, and the shapes of the sliders are the same as those of the sliding grooves; fastening screws 17 are installed on each sliding groove, and the cross-sectional shape of the sliding groove is a trapezoid with a smaller upper part and a larger lower part.

[0033] More specifically, after combining the flat plate 14, the convex edges 15, and the sliding grooves, a dovetail-shaped groove body is formed. This shape of the groove body has the characteristics of convenient disassembly and reliable installation combination, which can ensure a firm connection between the antenna and the turntable and ensure the strength and accuracy of the system.

[0034] The multimode feed module 2 uses a TE21 mode differential mode coupler. When the target deviates from the antenna electrical axis, the incoming wave of the target in the waveguide transmission line will not only excite the main mode but also excite higher-order modes. The main mode signal is used as the sum signal, part of which is used for normal communication and part is sent to the monopulse tracking system; the higher-order mode signal forms the difference signal, which is also sent to the monopulse tracking receiver 5. The sum signal and difference signal entering the monopulse tracking receiver 5 participate in the monopulse tracking of the entire system.

[0035] The orthomode coupler 3 can separate mutually orthogonal receiving RF signals in the range of 17 - 20.2 GHz and transmitting RF signals in the range of 27 - 32 GHz. The output interface of the receiving path is a standard BJ220 flange interface, and the output interface of the transmitting path is a standard BJ260 flange interface.

[0036] The ring focus reflector antenna 1, the multimode feed module 2, and the orthomode transducer 3 are all connected by waveguides, and the three together form an antenna assembly. After the external transmission signal is input, it is directly connected to the transmitting BJ260 waveguide interface of the orthomode transducer, and the high-frequency electromagnetic wave signal is radiated through this antenna assembly. The high-frequency electromagnetic wave signal in space is received by the antenna and then transmitted to the user through the receiving BJ220 waveguide interface of the orthomode transducer.

[0037] The RF front-end 4 includes three waveguide input ports in the K band. The waveguide ports all adopt standard BJ220 waveguide ports. The first waveguide port inputs the sum signal, and the second and third waveguide ports input the difference signals. The two difference signals respectively transmit the left-handed circularly polarized signal and the right-handed circularly polarized signal. An RF switch is arranged therein to realize the selection of the two circularly polarized signals.

[0038] As Figure 3 shown, an amplifier and a filter are arranged in the RF front-end 4 to realize the amplification and filtering of the available signal, and the system amplification gain is 60 dB. Two-stage frequency converters are arranged in the RF front-end 4. The first-stage frequency converter completes the conversion of the signal from the K band to the L band, and the second-stage frequency converter completes the conversion of the signal from the L band to 70 MHz. A frequency source is also arranged in the RF front-end 4 to provide local oscillator signals for the two-stage frequency converters. The external interfaces of the RF front-end 4 include 2 waveguide ports, 1 power port, 1 control port, 1 intermediate-frequency port, and 2 low-frequency ports.

[0039] The monopulse tracking receiver 5 receives the 70 MHz signal output by the RF front-end 4 through an RF cable, and outputs the two required azimuth error signals and elevation error signals through modules and processes such as band-pass filtering, digital control attenuator, signal amplifier, analog-to-digital converter, phase-locked carrier recovery module, AGC calculation, azimuth error calculation, and elevation error calculation.

[0040] Three serial interfaces are arranged inside the monopulse tracking receiver 5, which communicate with the monitoring computer, the servo turntable, and the monitoring and processing unit respectively to obtain information such as azimuth error voltage, elevation error voltage, AGC voltage, and locking indication, and send them to the corresponding ports.

[0041] The servo turntable 6 is a portable and detachable turntable. Among them, the antenna part, the turntable main body part, and the turntable legs can be detached independently. The detachable parts all adopt the structure form of dovetail grooves. Inside the servo turntable 6, there is a servo controller. The servo controller is the automatic control core unit of the system, which realizes the antenna servo motion control, completes the arithmetic processing of the antenna target pointing, realizes the antenna tracking algorithm, and realizes the automatic tracking of the system. An inclination sensor is installed inside the servo turntable 6, which is responsible for providing the system reference inclination information. A dual GPS receiver module is installed inside the servo turntable 6, which is responsible for receiving the system reference true north information, the system local longitude, latitude and altitude information, and the time reference provided by the GPS antenna 9.

[0042] There are three turntable legs 7 in total. They are processed by carbon fiber air inflation method through mold opening, and are mainly composed of carbon fiber and aluminum alloy materials. Each leg is also provided with a disassembly, locking and adjustment mechanism. The legs and the turntable main body are connected by dovetail groove buckles, and the legs and the external ground are fixed by leg adjustment cups. The leveling of the turntable can be completed through the adjustment and locking mechanism at the end of the legs.

[0043] A vertical groove with a trapezoidal cross-section is opened on the side of the support platform. The lower bottom edge of the trapezoid is located inside the groove, and the upper bottom edge is located on the surface of the groove; fixing bolts are installed on the inclined side of the vertical groove; the shape of the connecting end of each turntable leg 7 is the same as the shape of the vertical groove; each fixing bolt is used to abut against the connecting end of the turntable leg 7 through its end to realize the fixation between the turntable leg 7 and the support platform.

[0044] The GPS antenna mechanism includes an antenna bracket 12. Two U-shaped openings are opened at the top of the antenna bracket 12. A folding tube 8 is installed on the U-shaped openings. GPS antennas 9 are installed at both ends of the folding tube 8. The folding tube 8 includes at least two sections of hollow tubes, and the adjacent hollow tubes are connected by a ferrule; the ferrule includes a first snap ring and a second snap ring respectively sleeved on the ends of adjacent two hollow tubes. A pin shaft is penetrated through one side of the first snap ring, the second snap ring is sleeved on both ends of the pin shaft, and the other sides of the first snap ring and the second snap ring are clamped. The folding tube 8 is made of carbon fiber round tube, which is composed of a folding joint and a quick-release component, and the design form is quick-release, which is convenient for disassembly. The GPS antenna 9 is installed at both ends of the dual GPS mechanism and fixed by bolts and nuts. A total of two GPS antennas are installed in the system, which can provide positioning and orientation functions.

[0045] The bracket 10 includes a support platform. At least three turntable legs 7 are connected to the side of the support platform. The connecting end of each turntable leg is higher than the supporting end, and an adjusting foot cup is installed at the supporting end of each turntable leg 7.

[0046] A Ka-band automatic tracking system applied to a satellite communication system according to the present invention can achieve real-time communication with a mobile satellite. The system has the ability of monopulse self-tracking, with fast tracking speed and high tracking accuracy. Signals are transmitted and received through a ring focus reflector antenna, the sum and difference signals are separated and the transmitted and received signals are separated through a differential-mode coupler multimode feed module and a quadrature-mode coupler, signal filtering, amplification, frequency conversion, etc. are achieved through a radio frequency front end, and the monopulse tracking of the system can be achieved through a monopulse tracking receiver and a servo tracking turntable. The system can ultimately achieve high-speed and high-precision tracking capabilities.

Claims

1. A Ka-band automatic tracking system applied to a satellite communication system, characterized in that, it includes a bracket (10), a servo turntable (6) is installed on the bracket (10), a monopulse tracking receiver (5) is installed on the servo turntable (6), and the servo turntable (6) and the monopulse tracking receiver (5) are connected by a radio frequency cable; a vertical rod (11) is arranged on the servo turntable (6), a connecting component is hinged to the top end of the vertical rod (11), and a box body with openings at the top and both sides is detachably installed on the connecting component; a multimode feed module (2) and an orthomode coupler (3) are installed between the two side plates of the box body, a ring focus reflector antenna (1) and a GPS antenna mechanism are installed on the outside of one side plate of the box body, and a radio frequency front end (4) is installed on the outside of the other side plate; the multimode feed module (2) is used to excite sum and difference signals of the signal, the orthomode coupler (3) is used to separate mutually orthogonal received signals of 17 - 20.2 GHz and transmitted signals of 27 - 32 GHz in the waveguide transmission line; the ring focus reflector antenna (1) and the multimode feed module (2) are connected by a waveguide, the multimode feed module (2) and the orthomode coupler (3) are connected by a waveguide, the multimode feed module (2) and the radio frequency front end (4) are connected by a radio frequency cable, and the radio frequency front end (4) and the monopulse tracking receiver (5) are connected by a radio frequency cable; the servo turntable (6) is used to adjust the orientation of the ring focus reflector antenna (1) according to the azimuth error signal and elevation error signal output by the monopulse tracking receiver (5), so that the ring focus reflector antenna (1) continuously tracks the satellite signal.

2. A Ka-band automatic tracking system applied to a satellite communication system as claimed in claim 1, characterized in that, the GPS antenna mechanism includes an antenna bracket (12), two U-shaped openings are provided at the top end of the antenna bracket (12), a folding tube (8) is installed on the U-shaped openings, and GPS antennas (9) are installed at both ends of the folding tube (8).

3. A Ka-band automatic tracking system applied to a satellite communication system as claimed in claim 2, characterized in that, the folding tube (8) includes at least two sections of hollow tubes, and adjacent hollow tubes are connected by a ferrule; the ferrule includes a first snap ring and a second snap ring respectively sleeved on the ends of adjacent two hollow tubes, a pin shaft penetrates through one side of the first snap ring, the second snap ring is sleeved on both ends of the pin shaft, and the other sides of the first snap ring and the second snap ring are clamped.

4. A Ka-band automatic tracking system applied to a satellite communication system as claimed in claim 1, characterized in that, the connecting component includes two oppositely arranged ear plates (13), the two ear plates (13) are respectively connected to both ends of the same rotating shaft, and the tops of the two ear plates (13) are connected by a flat plate (14); convex edges (15) extend upward on both sides of the flat plate (14), and sliding grooves are provided on the inner sides of the two convex edges (15); Sliders are provided on both sides of the bottom plate (16) of the box body and extend outward. The shape of the sliders is the same as that of the sliding grooves. A fastening screw (17) is installed on each of the sliding grooves.

5. A Ka-band automatic tracking system applied to a satellite communication system according to claim 4, characterized in that the cross-sectional shape of the sliding groove is a trapezoid with a smaller upper part and a larger lower part.

6. A Ka-band automatic tracking system applied to a satellite communication system according to claim 1, characterized in that the bracket (10) includes a support platform. At least three turntable legs (7) are connected to the side surface of the support platform. The connection end of each turntable leg is higher than the support end. An adjusting foot cup is installed at the support end of each turntable leg (7).

7. A Ka-band automatic tracking system applied to a satellite communication system according to claim 6, characterized in that a vertical groove with a trapezoidal cross-section is formed on the side surface of the support platform. The lower bottom edge of the trapezoid is located inside the groove and the upper bottom edge is located on the surface of the groove. A fixing bolt is installed on the inclined side of the vertical groove; the shape of the connection end of each turntable leg (7) is the same as that of the vertical groove; each fixing bolt is used to abut against the connection end of the turntable leg (7) through its end to realize the fixation between the turntable leg (7) and the support platform.

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