An antenna device and a tracking and capturing method for tracking and capturing a drone

Abstract

The application provides an antenna device for tracking and capturing a UAV and a tracking and capturing method, and belongs to the technical field of antennas. The application provides a fast and effective recapturing technology after a target UAV is lost, greatly improves the survival ability of the UAV on the sea, avoids loss of the UAV, further increases the time length of information communication, and ensures long-time communication between the ship and the UAV.

Description

Technical Field

[0001] The present invention belongs to the field of antenna technology, and in particular relates to an antenna device and a tracking and capturing method for tracking and capturing a UAV. Background Art

[0002] With technological advancements and practical application needs, the use of drones is becoming increasingly widespread. The data link between drones and ships serves as the "nerve center" of the drone system, responsible for transmitting and receiving data. The drone system is a crucial component of drones, enabling remote control, telemetry, tracking and positioning, and information transmission.

[0003] With the continued increase in deep-sea operations, such as deep-sea fishing, drones will play a significant role in future deep-sea operations. The reliability of the communication link between ships and drones not only determines the smooth transmission of data, but also the safe landing of drones. Therefore, the research on stable and efficient methods suitable for offshore environments that enable drones to complete their assigned tasks safely and efficiently is of great significance. Summary of the Invention

[0004] In view of this, the present invention has the characteristics of simple structural design and high reliability, and focuses on proposing a technology for quickly and effectively recapture the target (UAV) after it is lost, which greatly improves the survivability of the UAV at sea and avoids the loss of the UAV. At the same time, it also further increases the duration of information communication and ensures long-term communication between the ship and the aircraft.

[0005] The present invention adopts the following technical solutions to achieve the above technical effects:

[0006] An antenna device for tracking and capturing a drone, comprising an antenna mount and an antenna surface mounted on the antenna mount, and also comprising a servo control system mounted on the antenna mount, wherein the servo control system includes in-cabin equipment and out-cabin equipment;

[0007] The equipment inside the cabin includes a host computer and a receiver. The host computer controls and monitors the status of the antenna device and can perform human-computer interaction. The receiver receives the intermediate frequency signal, demodulates the error voltage, and provides it to the antenna control unit to ensure stable pointing of the antenna towards the drone.

[0008] The extravehicular equipment includes a high-precision measurement unit, an antenna control unit, an azimuth axis zeroing switch, a gyroscope, and a radio frequency front end. The high-precision measurement unit is used to measure and output the ship's heading, roll, pitch, longitude, and latitude data. The antenna control unit is the central nervous system for antenna pointing tracking, integrating multiple data and calculating and outputting the pointing angles of each axis. The azimuth axis zeroing switch calibrates the azimuth axis angle after power-on. The gyroscope senses and outputs the spatial motion rate of the azimuth and pitch axes. The radio frequency front end down-converts the radio frequency signal.

[0009] The antenna device's default operating mode is program-guided. The host computer calculates the target drone's geographic angle based on the target drone's longitude, latitude, and altitude information, as well as the longitude and latitude of the antenna's location. This target geographic angle is then transmitted to the antenna control unit. The antenna control unit then combines the ship's heading, roll, and pitch information output by the high-precision measurement unit to ultimately calculate the target deck angle corresponding to the drone's location. This is then driven by the various axis drives and actuator motors to ensure the antenna is always pointed at the target drone.

[0010] When the antenna device is measuring the target position or the program guidance does not meet the pointing accuracy requirements, it switches to automatic tracking, so that the antenna azimuth axis works in a single-pulse tracking state according to the azimuth axis error voltage reported by the receiver, and the pitch axis works in a program-guided state according to the pitch axis target geographic angle calculated and output by the host computer. During the movement of the target UAV, the rate of change of its position in the pitch direction is much smaller than that in the azimuth direction. At the same time, since the antenna surface is a rectangular surface, its beam width in the pitch direction is wider than that in the azimuth direction. Taking all the above into consideration, the pitch axis can effectively track the target UAV by always maintaining the program-guided working mode. However, the beam width in the azimuth direction is narrow and the target UAV moves at a fast speed. In order to further improve the tracking accuracy in this direction, the azimuth axis working mode needs to introduce a single-pulse tracking mode. The single-pulse tracking mode is a fully closed-loop tracking mode, which can avoid the influence of the factors mentioned above. The ultimate goal is to point the antenna at the target UAV with high precision, and ultimately achieve precise pointing of the antenna to the target UAV.

[0011] The azimuth-axis motor and pitch-axis motor of the antenna mount are both equipped with encoders. The encoder provides the actual pointing position information of the antenna mount to the antenna control unit, and compares it with the theoretical pointing position information calculated by the antenna control unit itself or the theoretical pointing position information sent by the host computer, and sends an angular error signal to the drive component. The drive component drives the pitch motor and azimuth motor to rotate the antenna in the direction of reducing the error.

[0012] Furthermore, the antenna control unit realizes the pointing of the antenna to the drone as follows:

[0013] The position of the UAV in the geocentric coordinate system is calculated by coordinate transformation;

[0014] Furthermore, the high-precision measurement unit is an INS / GNSS combined navigation unit consisting of an inertial navigation system and dual GPS / BD receivers; the inertial navigation system is an attitude calculation unit using three fiber optic gyroscopes and three quartz flexible accelerometers as measurement devices and a DSP as the computing core.

[0015] A method for capturing a drone using an antenna is implemented by an antenna device for tracking and capturing a drone as described in the claims; the details are as follows:

[0016] During the communication establishment process between the drone and the antenna, the drone sends the antenna its real-time position information and flight time information. This ensures that if communication fails for a long time, both parties agree to move to the same area so that communication can be established.

[0017] After the communication is interrupted, the drone sends a single-carrier signal at the lowest frequency in the communication band to increase the beam width and facilitate successful antenna capture.

[0018] Furthermore, there are two situations in which communication is interrupted. One situation is when a drone passes directly over the antenna, and communication is interrupted due to the influence of the antenna's zenith blind spot. The drone is allowed to keep flying straight, and the antenna is pointed to a position where the drone may exit the blind spot in the future, and communication is re-established until the drone flies out of the antenna blind spot.

[0019] Another situation is when the communication is interrupted when the UAV is not passing directly over the antenna. After the communication is interrupted, let the UAV hover at the lost point, and the search order of the antenna should be from the center wave position of the search map to search outward step by step.

[0020] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0021] The structural design is simple and adopts a two-axis support form to improve the reliability of the system;

[0022] The antenna control unit has the function of autonomously calculating the azimuth angle of the target drone, thus ensuring that the antenna can still stably point to the target even if the host computer fails, thereby improving the safety redundancy of the system;

[0023] By introducing the technology of rapid recapture of target drones after they are lost, the maximum and longest communication between ships and aircraft can be guaranteed. More importantly, it can prevent accidents in which drones eventually fall into the sea, thus saving system costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 1 is a schematic structural diagram of the antenna system of the present invention;

[0025] Figure 2 It is a structural diagram of the mount of the antenna of the present invention;

[0026] Figure 3 It is a composition diagram of the antenna servo system of the present invention;

[0027] Figure 4 This is a diagram of the antenna control loop composition of the present invention;

[0028] Figure 5 This is a schematic diagram of the search range and path of the ship-borne antenna of the present invention.

[0029] In the figure: 1. Antenna surface, 2. Slip ring, 3. Inertial navigation, 4. Azimuth straight cylinder, 5. Counterweight, 6. Pitch box, 7. Left support arm, 8. Azimuth drive device, 9. Right support arm, 10. Pitch drive device. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] Reference Figures 1 to 5 ,This paper proposes a design idea for a shipborne UAV system, and discusses it from four aspects : ,structure design, servo design, pointing algorithm and loss recapture.

[0032] 1) Structural design

[0033] The antenna of the present invention consists of an antenna surface and an antenna base, wherein the antenna surface adopts a rectangular array antenna and the antenna base adopts an AE two-axis mount, wherein the A axis can rotate continuously 360 degrees and the E axis rotation angle range is -10 degrees to +90 degrees.

[0034] The antenna base consists of a pitch device and an azimuth device, with a total weight of approximately 80Kg.

[0035] The azimuth device consists of an azimuth straight cylinder, a slip ring, an inertial guide, etc.

[0036] The pitch device consists of a pitch box, left and right arms, an azimuth drive device, a pitch drive device, a counterweight, etc.

[0037] Because the antenna prioritizes program-guided tracking during use, large structural errors can affect tracking accuracy. When the antenna is used to measure target positions, large azimuth errors can affect target measurements. For these reasons, the antenna structural error needs to be calibrated.

[0038] Traditional error calibration methods require the use of more measuring instruments and take up a lot of manpower and time costs, and are not suitable for batches of small antennas.

[0039] The basic principle of dynamic pointing error calibration is to install the antenna on a swing stage to track the target when the target geographical angle is known, and measure the swing stage attitude through high-precision inertial navigation. By changing the swing stage attitude, multiple sets of AE axis angles are measured, and the system error is calculated using the least squares method.

[0040] The AE antenna structure system error is shown in Table 1 below:

[0041] Table 1 AE antenna structure system error

[0042]

[0043] 2) Servo design

[0044] The servo system consists of in-cabin equipment and out-cabin equipment. The in-cabin equipment includes a distribution box, a host computer, a receiver, and a power supply unit; the out-cabin equipment includes a high-precision measurement unit, a slip ring, a CAN junction box, an ACU, an azimuth axis zero switch, an azimuth axis drive, an azimuth axis motor, a gyroscope, a pitch axis drive, a pitch axis motor, a RF front end, and a pitch axis upper limit switch and lower limit switch.

[0045] The distribution box realizes 220V AC output, which is the main power supply of the system;

[0046] The host computer realizes system status monitoring and equipment control, and is a human-computer interaction tool;

[0047] The receiver receives the intermediate frequency signal, demodulates the error voltage and provides it to the ACU, so that the antenna can be stably pointed at the drone.

[0048] The power supply unit converts AC 220V into DC 24V to provide power to related back-end equipment;

[0049] The high-precision measurement unit measures and outputs ship heading, roll, pitch, longitude, and latitude data;

[0050] The slip ring ensures that the RF link is not interrupted when the antenna azimuth axis rotates continuously 360 degrees;

[0051] The CAN junction box mainly plays an integrating role and can realize the effective mounting of multiple CAN node devices;

[0052] The ACU is the central nervous system of antenna pointing tracking, realizing the integrated processing of multiple data and calculating and outputting the pointing angle of each axis;

[0053] The azimuth axis zero switch realizes the angle calibration of the azimuth axis after power-on;

[0054] The azimuth axis drive and the azimuth axis motor realize the effective movement of the azimuth axis under the joint action of the drive and the motor;

[0055] The gyro sensor outputs the spatial motion rate of the azimuth axis and pitch axis;

[0056] The pitch axis drive and the pitch axis motor realize the effective movement of the pitch axis under the joint action of the drive and the motor;

[0057] The RF front end realizes down-conversion of RF signals, facilitating long-distance signal transmission;

[0058] In addition to limiting the over-limit movement of the pitch axis, the upper and lower limit switches of the pitch axis also have the function of calibrating the angle of the pitch axis after power is turned on.

[0059] The system working modes are designed as follows: manual control, command position, standby, automatic tracking, and program guidance.

[0060] Manual control: You can specify the azimuth axis (or pitch axis) to rotate uniformly in a specified direction and at a specified speed;

[0061] Command position: Controls the rotation of the two axes of the antenna to fix the antenna's geographic pointing direction at the azimuth and elevation angles given by the command;

[0062] Standby: The antenna azimuth and pitch axis motors are disabled;

[0063] Automatic tracking: The antenna azimuth axis works in a single pulse tracking state according to the azimuth axis error voltage, and the elevation axis works in a program guidance state according to the digital guidance angle;

[0064] Program guidance: Calculate the geographic angle of the target UAV based on the longitude, latitude, and altitude information of the target UAV, as well as the local longitude and latitude information of the ship, and use this as the target geographic angle to control the antenna to always point at the target UAV.

[0065] The default working mode of the antenna is program guidance. It switches to automatic tracking when measuring the target position or when program guidance does not meet the tracking accuracy requirements.

[0066] A servo control system is a feedback closed-loop control system that relies on position error. It requires fast response, high tracking accuracy, and a wide speed regulation range. Furthermore, the equipment must operate under dynamic conditions onboard a ship. Therefore, the servo control system consists of three feedback closed-loop control loops: current, speed, and position.

[0067] In a servo control system, the current and velocity loops are designed into the driver, while the position loop is controlled by the controller. The guide position is compared with the actual antenna position, generating an angular error signal that is sent to the driver. The driver then drives the motor to rotate the antenna in a direction that minimizes the error.

[0068] Because the antenna primarily operates via program guidance, its pointing accuracy in this mode is highly dependent on the precision and accuracy of the data output by the high-precision measurement unit. To improve the pointing accuracy of the antenna system, the servo system utilizes a high-precision measurement unit, an INS / GNSS integrated navigation system consisting of an inertial navigation system and dual GPS / BD receivers. The inertial navigation system (INS) utilizes three fiber optic gyroscopes and three quartz flexible accelerometers as measurement devices, with a high-precision attitude calculation unit powered by a DSP. By combining this with the positioning and orientation information from the dual GPS / BD receivers, it overcomes the heading attitude drift inherent in INS alone, achieving highly accurate angular output.

[0069] 3) Pointing algorithm

[0070] Antenna pointing is to calculate the position of the UAV in the geographic coordinate system through coordinate transformation based on the position of the UAV in the geocentric coordinate system.

[0071] 4) Lost and recaptured

[0072] When a shipborne antenna is tracking a drone, if communication between the ship and the drone is lost, the antenna loses its spatial position. If the communication interruption persists for a long time, the drone may be completely lost, ultimately causing it to crash into the sea. This paper proposes a method for rapidly reacquiring a target after a shipborne antenna loses it.

[0073] In order to solve the above problems, during the process of establishing communication between the drone and the ship, in addition to sending the drone's real-time position information to the ship, the drone also sends the drone's flight time information to the ship, ensuring that if communication cannot be established for a long time, both parties agree to move to the same area so that communication can finally be established, thereby avoiding the drone falling into the sea.

[0074] Once communication is interrupted, cooperation between the ship and the drone is required to increase the probability of the drone being recaptured.

[0075] Once communication is interrupted, the drone antenna sends a single-carrier signal at the lowest frequency in the communication band to increase the beam width, making it easier for the ship-borne antenna to capture successfully.

[0076] Communication interruption occurs in two ways. One is when a drone passes directly overhead, due to the antenna's blind spot. To prevent this, the drone is directed to maintain direct flight, with the antenna pointed toward a location where the drone may exit the blind spot. The drone then waits until communication is reestablished. A timer is activated when the drone enters the blind spot. If the target drone remains unseen for 10 minutes, the target is considered lost, the antenna's blind wait is terminated, and a wide-area search mode is activated.

[0077] Another situation is when the communication is interrupted when the UAV is not passing directly over the antenna. After the communication is interrupted, let the UAV hover at the lost point, and the search order of the antenna should be from the center wave position of the search map to search outward step by step.

[0078] It is not the case that the larger the search range, the higher the capture probability. Blindly expanding the search range will often cause the search cycle to become longer, resulting in the inability to quickly achieve capture. Therefore, the search range should be designed based on the search cycle and the probability of discovery. The ripple center distance in the present invention is the half-power beam width. times.

[0079] During the communication establishment process between the drone and the antenna, the drone sends the antenna its real-time position information and flight time information. This ensures that if communication fails for a long time, both parties agree to move to the same area so that communication can be established.

[0080] If communication between the ship and the drone has not been established, when the drone's flight time is only half an hour, the ship and the drone will sail simultaneously towards the position of the ship before the communication was interrupted, in order to finally detect the drone and establish communication with the help of the ship's omnidirectional antenna.

[0081] After the communication is interrupted, the drone transmits a single-carrier signal at the lowest frequency within the communication band to increase the beam width and facilitate successful antenna capture;

[0082] The receiver adds a "pre-lock" status report. When the antenna is aligned with the drone signal sidelobe, the receiver reports the pre-lock status to the antenna control unit, thereby informing the antenna control unit that the antenna is now pointing close to the target drone.

[0083] The wide range search mode is to start with a certain elevation angle and a certain gradient (usually half power beam width) This operating mode conducts a wide-area search of the airspace in a decreasing manner (by multiples). For each pitch angle, the azimuth axis performs a rapid 360° circular motion. If the target drone is not found (the receiver does not report a "pre-lock" status), the pitch angle is reduced by a certain amount, causing the azimuth axis to perform a rapid 360° circular motion again. If the target drone is found (the receiver reports a "pre-lock" status), the system switches to a narrow-area search mode, fixing the pitch angle and conducting a precise search within 5° to the left and right of the azimuth's geographic pointing until the receiver reports a change from "pre-lock" to "lock," thereby accurately capturing the target drone.

[0084] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An antenna device for tracking and capturing a UAV, comprising an antenna mount and an antenna surface mounted on the antenna mount, characterized in that: Also included is a servo control system carried on the antenna mount, the servo control system including in-cabin equipment and out-cabin equipment; The equipment inside the cabin includes a host computer and a receiver. The host computer controls and monitors the status of the antenna device and can perform human-computer interaction. The receiver receives the intermediate frequency signal, demodulates the error voltage, and provides it to the antenna control unit to ensure stable pointing of the antenna towards the drone. The extravehicular equipment includes a high-precision measurement unit, an antenna control unit, an azimuth axis zeroing switch, a gyroscope, and a radio frequency front end. The high-precision measurement unit is used to measure and output the ship's heading, roll, pitch, longitude, and latitude data. The antenna control unit is the central nervous system for antenna pointing tracking, integrating multiple data and calculating and outputting the pointing angles of each axis. The azimuth axis zeroing switch calibrates the azimuth axis angle after power-on. The gyroscope senses and outputs the spatial motion rate of the azimuth and pitch axes. The radio frequency front end down-converts the radio frequency signal. The default working mode of the antenna device is program-guided. The host computer calculates the geographic angle of the target drone based on the longitude, latitude, and altitude information of the target drone, as well as the longitude and latitude information of the antenna location, and sends this target geographic angle to the antenna control unit. The antenna control unit then combines the ship's heading, roll, and pitch information output by the high-precision measurement unit to finally calculate the target deck angle corresponding to the drone's location. This is used to drive each axis and the actuator motor to finally drive the antenna to keep it pointing at the target drone at all times. When the antenna device is measuring the target position or the program guidance does not meet the pointing accuracy requirements, it switches to automatic tracking, so that the antenna azimuth axis works in the single pulse tracking state according to the azimuth axis error voltage reported by the receiver, and the pitch axis works in the program guidance state according to the pitch axis target geographical angle calculated and output by the host computer; The azimuth-axis motor and pitch-axis motor of the antenna mount are both equipped with encoders. The encoder provides the actual pointing position information of the antenna mount to the antenna control unit, and compares it with the theoretical pointing position information calculated by the antenna control unit itself or the theoretical pointing position information sent by the host computer, and sends an angular error signal to the drive component. The drive component drives the pitch motor and azimuth motor to rotate the antenna in the direction of reducing the error.

2. The antenna device for tracking and capturing a drone according to claim 1, characterized in that: The antenna control unit realizes the pointing of the antenna to the drone as follows: The position of the UAV in the geocentric coordinate system is calculated through coordinate transformation.

3. The antenna device for tracking and capturing a drone according to claim 1, characterized in that: The high-precision measurement unit is an INS / GNSS combined navigation unit consisting of an inertial navigation system and dual GPS / BD receivers; the inertial navigation system uses three fiber optic gyroscopes and three quartz flexible accelerometers as measurement devices, and is an attitude calculation unit with a DSP as the computing core.

4. A method for capturing a drone using an antenna, characterized in that: The method is implemented by an antenna device for tracking and capturing a drone according to any one of claims 1 to 3; specifically as follows: During the communication establishment process between the drone and the antenna, the drone sends the antenna its real-time position information and flight time information. This ensures that if communication fails for a long time, both parties agree to move to the same area so that communication can be established. After the communication is interrupted, the drone transmits a single-carrier signal at the lowest frequency within the communication band to increase the beam width and facilitate successful antenna capture; The receiver adds a "pre-lock" status report. When the antenna aligns with the drone's signal sidelobe, the receiver reports the pre-lock status to the antenna control unit, thereby informing the antenna control unit that the antenna is now pointing close to the target drone.

5. The method for capturing a drone using an antenna according to claim 4, wherein: There are two situations in which communication is interrupted. One is when a drone passes directly above the antenna and communication is interrupted due to the antenna's zenith blind spot. The drone is instructed to maintain direct flight and the antenna is directed toward a location where the drone may exit the blind spot in the future, waiting until the drone flies out of the blind spot and communication is re-established. The timing function is activated when the drone enters the zenith blind spot and communication is interrupted. If the target drone cannot be captured within the specified time, the target is considered completely lost, the antenna's blind waiting is interrupted, and a wide-area search mode is entered. Another situation is the communication interruption that occurs when the drone does not pass directly above the antenna; After the communication is interrupted, let the UAV hover at the loss point, and the antenna search order should be based on the search pattern center wave position to gradually search outward; The large-scale search mode is a working mode in which the pitch angle starts at a certain elevation angle and conducts a large-scale search of the airspace in a specific gradient decreasing manner; for each pitch angle, the azimuth performs a 360° rapid circular motion; if the target drone is not found, the pitch angle is reduced by a certain amount and the azimuth performs a 360° rapid circular motion again; if the target drone is found, the pitch angle is fixed, and the azimuth axis performs a precise search within 5° to the left and right of the azimuth geographic pointing until the receiver reports that the status changes from "pre-lock" to "lock", thereby achieving accurate capture of the target drone.

6. The method for capturing a drone using an antenna according to claim 5, wherein: The specific gradient is the half-power beam width times.

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