Method and device for measuring the radar cross section of a ship

Abstract

The application provides a ship radar cross section measurement method, device and system. The ship radar cross section measurement method comprises the following steps: reaching an i-th hovering position by a drone controlled by a remote operation platform, i is an element in [1, N), and N is a positive integer greater than 1; calibrating an i-th pitch angle between the drone at the i-th hovering position and a ship to be measured; measuring the ship to be measured by the drone at the i-th pitch angle and multiple azimuth angles to obtain multiple radar cross sections (RCS); and moving the drone from the i-th hovering position to an (i+1)-th hovering position controlled by the remote operation platform.

Description

Technical Field

[0001] This invention relates to the field of radar technology, and specifically to a method and apparatus for measuring the radar cross-section of a ship. Background Technology

[0002] Radar cross section (RCS) is a physical quantity that describes a target's electromagnetic scattering capability. It is related to factors such as the target's geometry, physical characteristics, and radar operating parameters. RCS information is widely used in radar target identification, stealth and anti-stealth technologies, and microwave remote sensing image recognition.

[0003] Currently, methods for measuring the RCS of ships typically employ scaled-down electromagnetic models of the target and simulations of the target's reflection characteristics based on electromagnetic theory. While these methods reduce the cost of acquiring RCS data, their accuracy is relatively low due to the idealized simulation environment. Alternatively, full-scale physical measurement can be used, based on actual objects. This method offers higher reliability but requires appropriate experimental facilities and equipment, resulting in higher costs and longer measurement cycles. Summary of the Invention

[0004] In view of the above problems, the present invention provides a method, apparatus and system for measuring the radar cross-section of ships.

[0005] According to a first aspect of the present invention, a method for measuring the radar cross section (RCS) of a ship is provided, comprising: controlling a UAV to reach an i-th hovering position, i∈[1,N), where N is a positive integer greater than 1, via a remote operating platform; calibrating the i-th pitch angle between the UAV and the ship to be measured at the i-th hovering position; measuring the ship to be measured by the UAV at the i-th pitch angle and multiple azimuth angles to obtain multiple radar cross sections (RCS); and controlling the UAV to move from the i-th hovering position to the (i+1)-th hovering position via a remote operating platform.

[0006] According to an embodiment of the present invention, the UAV includes a laser sensor, a radar, and a pitch controller. Calibrating the i-th pitch angle between the UAV and the ship to be measured at the i-th hovering position includes: when the current position of the UAV is determined to be the i-th hovering position, adjusting the attitude of the UAV according to feedback information from the laser sensor to align the radar with the ship to be measured; and calibrating the i-th pitch angle of the radar of the UAV at the attitude by means of the pitch controller.

[0007] According to an embodiment of the present invention, the pitch controller includes a servo motor and a gyroscope. The pitch controller calibrates the i-th pitch angle of the UAV's radar under the given attitude, including: adjusting the rotation angle of the servo motor so that the feedback parameter of the gyroscope is a preset parameter, the preset parameter corresponding to the i-th pitch angle.

[0008] According to an embodiment of the present invention, the ship to be measured is located on a ship rotation platform, and the unmanned aerial vehicle (UAV) is controlled to measure the ship at the i-th pitch angle and multiple azimuth angles to obtain multiple radar cross sections (RCS). This includes: controlling the rotation of the ship rotation platform through a remote operation platform to generate multiple azimuth angles between the UAV and the ship to be measured; and controlling the UAV to measure the ship at the i-th pitch angle and multiple azimuth angles to obtain multiple RCS.

[0009] According to an embodiment of the present invention, calibrating the pitch angle between a UAV and a ship to be measured in a hovering position includes: calibrating the hovering position of the UAV based on the relative position between the UAV and the ship to be measured; calibrating the nose direction of the UAV based on the communication information between the UAV and the ship's rotating platform; obtaining the measurement distance between the UAV and the ship to be measured and the flight altitude of the UAV after calibration; and calculating the pitch angle based on the measurement distance and flight altitude.

[0010] According to an embodiment of the present invention, before controlling the UAV to reach the i-th hovering position via the remote operation platform, the method further includes: initializing the remote control platform, which includes: clearing the PID parameters and loading the control commands.

[0011] According to an embodiment of the present invention, the pitch controller includes a feedback controller, which measures the ship under test at the i-th pitch angle and multiple azimuth angles using a UAV to obtain multiple radar cross sections (RCS). This includes: controlling the UAV to maintain the i-th pitch angle constant under the control of the feedback controller; controlling the UAV to transmit electromagnetic wave signals to the ship under test via radar at multiple azimuth angles; receiving reflected echo signals of the electromagnetic waves via radar; and transmitting the reflected echo signals to a remote operating platform via the UAV to obtain multiple RCS.

[0012] According to an embodiment of the present invention, the radar control interface includes operating control commands, mode setting commands, antenna operating parameter settings, antenna scanning parameter settings, processing parameter settings, and reporting status configuration.

[0013] A second aspect of the present invention provides a device for measuring the radar cross section (RCS) of a ship, comprising: a control module for controlling a UAV to reach an i-th hovering position via a remote operating platform, i ∈ [1, N), where N is a positive integer greater than 1; a calibration module for calibrating the i-th pitch angle between the UAV and the ship to be measured at the i-th hovering position; a measurement module for measuring the ship to be measured by the UAV at the i-th pitch angle and multiple azimuth angles to obtain multiple RCSs; and a movement module for controlling the UAV to move from the i-th hovering position to the (i+1)-th hovering position via a remote operating platform.

[0014] A third aspect of the present invention provides a system for measuring the radar cross-section of a ship, comprising: an unmanned aerial vehicle (UAV); a ship rotation platform; and a remote operation platform for controlling the UAV and the ship rotation platform to perform the aforementioned method for measuring the radar cross-section of a ship. Attached Figure Description

[0015] The above-described features, other objects, and advantages of the present invention will become clearer from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0016] Figure 1 A schematic diagram illustrating a method for measuring the radar cross-section of a ship according to an embodiment of the present invention is shown.

[0017] Figure 2 A flowchart illustrating a method for measuring the radar cross-section of a ship according to an embodiment of the present invention is shown schematically.

[0018] Figure 3 A flowchart illustrating the calibration of the pitch angle according to an embodiment of the present invention is shown schematically;

[0019] Figure 4 A flowchart illustrating the measurement of radar cross-section according to an embodiment of the present invention is shown schematically;

[0020] Figure 5 A flowchart illustrating the calibration of the pitch angle according to another embodiment of the present invention is shown schematically;

[0021] Figure 6 A schematic diagram of a device for measuring the radar cross-section of a ship according to an embodiment of the present invention is shown; and

[0022] Figure 7 A block diagram of an electronic device suitable for a method of measuring the radar cross-section of a ship according to an embodiment of the present invention is shown schematically. Detailed Implementation

[0023] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0024] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0025] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0026] When using expressions such as "at least one of A, B, and C", they should generally be interpreted in accordance with the meaning that is commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B, and C, etc.).

[0027] Figure 1 A schematic diagram illustrating the measurement of a ship's radar cross-section according to an embodiment of the present invention is shown.

[0028] like Figure 1 As shown, when measuring the RCS of a ship, the ship is the target to be measured, and the equipment involved in the measurement includes a remote operation platform 110, a drone 120, and a ship rotation platform 130. The remote operation platform 110 includes a communication module 111 and a data processing system. The remote operation platform 110 can serve as a control terminal, capable of sending commands to other devices, receiving data, and processing data. The drone 120 includes a radar, a pitch angle controller, and a laser sensor. The ship rotation platform 130 includes an alignment sensor 131. The ship is positioned on the ship rotation platform 130. When the ship rotation platform 130 receives a rotation command sent by the remote operation platform 110 through the communication module 111, the ship rotation platform 130 begins to rotate. At this time, the ship rotates along with the ship rotation platform 130. During the ship's rotation, the radar on the drone 120 measures the rotating ship while maintaining its pitch angle to obtain the RCS of the ship in multiple azimuths. After measuring the RCS of the ship in multiple azimuths at that pitch angle, the measured data is transmitted to the remote operation platform 110. The data transmitted back is processed through the data processing system of the remote operation platform 110.

[0029] After completing the measurement at that pitch angle and transmitting the measurement data to the remote operation platform 110, the pitch angle of the radar is changed via the pitch angle controller. The RCS of the ship is measured at the next pitch angle until the RCS of the ship at all pitch angles has been measured.

[0030] Before measurement, the equipment involved in the measurement needs to be initialized. The initialization process includes initializing the remote operation platform 110, the drone 120, and the ship rotation platform 130.

[0031] After the remote operation platform 110 is powered on, it is initialized. The initialization process includes clearing the PID (proportional-integral-derivative) parameters, ensuring that the enable signal of the remote operation platform 110 is turned off by default when it is powered on, and ensuring that the enable signal is turned off by default after each power-on.

[0032] During the initialization phase, the remote operation platform 110 also needs to send measurement commands to the UAV 120. Upon receiving the measurement commands, the UAV 120 begins initialization. After starting, the UAV 120 determines its own position and its relative position with the ship's rotating platform 130. For example, the UAV can locate itself using a Global Navigation Satellite System (GNSS). If the initial position of the UAV 120 is at a designated position, it moves to the designated initial position based on its relative position with the ship's rotating platform 130. The initial designated position is the initial position for the UAV 120 to measure the ship's RCS, and the UAV 120 begins measuring the ship from this initial position. Simultaneously, it communicates with the ship's rotating platform 130 via a laser sensor mounted on its nose to adjust the UAV's nose direction towards the ship's rotating platform 130. After reaching the initial designated position, the UAV 120 calculates its radar pointing angle based on its own position and its relative position with the ship's rotating platform 130, and then sends an initialization command to the pitch controller to ensure correct initial radar pointing. After the radar system is powered on, it also needs to initialize and synchronize the clock system, and then wait for the start command. Once all the above tasks are completed, the UAV 120 sends a signal to the remote operation platform 110 to instruct the UAV 120 to complete the initialization.

[0033] The radar is mounted on the fuselage of the UAV 120, for example, by a gimbal mounted under the belly of the UAV 120. The UAV 120 needs to meet the installation requirements of the radar system equipment, such as weight, size, and power consumption, and the UAV, after being equipped with the radar, needs to meet experimental requirements such as flight altitude and endurance. For example, the maximum takeoff weight of the UAV 120 in this embodiment of the invention is 90 kg.

[0034] During the initialization phase, the remote operation platform 110 also needs to send control commands to the ship rotation platform 130. Upon receiving the control commands, the ship rotation platform 130 begins initialization. After powering on, the remote operation platform 110 loads the control commands and then sets the motor control mode, the gear ratio of the encoder signal output, and the proportional relationship between the control signal and the motor speed of the ship rotation platform 130. For example, the motor control mode is set to external control.

[0035] Since the ship rotation platform 130 is a closed-loop control system, zero drift needs to be suppressed to optimize control accuracy. Therefore, the ship rotation platform 130 can be tested and adjusted individually before each use. After the parameters are loaded and the encoder's initial position is recorded, the ship rotation platform 130 sends a signal to the remote operation platform 110 to instruct the ship rotation platform 130 to complete initialization.

[0036] After the remote operation platform 110, the drone 120 and the ship rotation platform 130 are fully initialized, they await the start command to perform RCS measurement.

[0037] Figure 2 A flowchart illustrating a method for measuring the radar cross-section of a ship according to an embodiment of the present invention is shown schematically. Figure 2 As shown, the method for measuring the radar cross-section of a ship in this embodiment includes operations S210 to S240.

[0038] In operation S210, the UAV is controlled by a remote operation platform to reach the i-th hovering position, where i ∈ [1, N), and N is a positive integer greater than 1. This invention constructs an RCS measurement model of a sea surface target by measuring the RCS data of the ship. The UAV needs to sequentially measure the ship at multiple hovering positions to obtain measurement data corresponding to each hovering position in order to construct the measurement model. The hovering position is a pre-set designated position that the UAV needs to reach.

[0039] In operation S220, the i-th pitch angle between the UAV and the ship to be measured at the i-th hovering position is calibrated.

[0040] During RCS measurement, the drone's hovering position and pitch angle need to be calibrated. After controlling the drone to fly to the designated hovering position, it is necessary to re-verify the drone's current position via GNSS to confirm whether it is indeed the designated hovering position. After confirming that the drone has reached the designated hovering position, the pitch angle is then calibrated.

[0041] When the UAV reaches any hovering position, it will form a pitch angle with the vessel being measured. Each hovering position corresponds to a pitch angle. In actual measurement, the UAV's entire fuselage cannot remain completely stationary. Therefore, the actual pitch angle formed between the UAV and the vessel after reaching a designated hovering position may not be the specified pitch angle. The attitude of the UAV at the i-th hovering position is adjusted to calibrate the i-th pitch angle at that moment.

[0042] By operating the S230, the UAV is used to measure the ship under test at the i-th pitch angle and multiple azimuth angles, and multiple radar cross sections (RCS) are obtained.

[0043] The process of measuring the RCS of a vessel requires considering changes to the horizontal azimuth angle (relative to sea level) and the vertical pitch angle (perpendicular to sea level) to obtain the RCS of the vessel from multiple observation angles. For example, the observation pitch angle of the UAV can be changed by altering its hovering position. Alternatively, by keeping the UAV's observation position fixed and controlling the vessel to rotate 360° in place, the UAV can be positioned at multiple horizontal azimuth angles to measure the vessel's RCS. Yet another example is that by keeping the vessel fixed and controlling the UAV to fly horizontally around it, the UAV can be positioned at multiple horizontal azimuth angles to measure the vessel's RCS.

[0044] In operation S240, the drone is controlled by the remote operation platform to move from the i-th hovering position to the i+1-th hovering position.

[0045] After completing the RCS measurement at the current pitch angle from the current hovering position, the UAV is controlled by the remote operation platform to move to the next hovering position to perform the RCS measurement at the next pitch angle. Operations S210 to S240 are repeated until the RCS measurement of the vessel under test is completed at all pitch angles.

[0046] Through the embodiments of this invention, multiple hovering positions are set to form multiple pitch angles with the target vessel, thereby completing the field measurement of electromagnetic scattering characteristics of the target vessel at sea. This allows for the construction of a complete physical model of the target, facilitating subsequent simulation of the target's reflection characteristics based on electromagnetic theory. Furthermore, the measurement process is simple to operate and highly practical for engineering applications.

[0047] Figure 3 A flowchart illustrating the calibration of the pitch angle according to an embodiment of the present invention is shown schematically. Figure 3 As shown, the UAV includes a laser sensor, radar, and pitch controller. The step of calibrating the i-th pitch angle between the UAV and the ship to be measured at the i-th hovering position in operation S220 includes operations S310 to S320.

[0048] When operating S310, after determining that the current position of the UAV is the i-th hovering position, the attitude of the UAV is adjusted according to the feedback information of the laser sensor so that the radar is aligned with the ship to be measured.

[0049] The drone uses its onboard laser sensor to communicate with the location of the vessel being measured, calibrates its position, and adjusts its nose to point towards the vessel. Adjusting the drone's hovering position and attitude aligns it with the radar. Based on the calibrated positioning information, the drone transmits its current position data to the remote operating platform.

[0050] When operating the S320, the i-th pitch angle of the UAV's radar is calibrated using the pitch controller at this attitude.

[0051] In this embodiment of the invention, the pitch controller includes a servo motor and a gyroscope. Calibrating the i-th pitch angle of the UAV's radar in this attitude using the pitch controller includes adjusting the rotation angle of the servo motor so that the feedback parameter of the gyroscope is a preset parameter. The preset parameter corresponds to the i-th pitch angle. When the pointing angle of the radar on the UAV reaches the preset pitch angle, the preset parameter characterizes the attitude information of the UAV at this moment.

[0052] In this embodiment of the invention, in order to improve the anti-interference capability of the UAV, the pitch controller also includes a feedback control program.

[0053] The steps of operating S230 to measure the ship under test using a UAV at the i-th pitch angle and multiple azimuth angles to obtain multiple radar cross sections (RCS) include: controlling the UAV to maintain the i-th pitch angle by controlling the UAV to emit electromagnetic wave signals to the ship under test through radar at multiple azimuth angles of the ship under test by the feedback controller; receiving the reflected echo signals of the electromagnetic waves through the radar; and sending the reflected echo signals to the remote operation platform through the UAV to obtain multiple RCS.

[0054] After the drone's attitude is determined, the feedback control program fine-tunes the angle of the servo motors based on the signals transmitted and received by the radar to ensure that the drone can maintain its flight attitude and improve the stability of the radar.

[0055] The radar receives various commands through multiple control interfaces to configure various measurement parameters during RCS measurement. These control interfaces include operational control commands, mode setting commands, antenna operating parameter settings, antenna scanning parameter settings, processing parameter settings, and reporting status configurations.

[0056] For example, operational control commands include operational, standby, self-test, maintenance, and reset control commands. Mode setting commands include settings for sea-to-surface, air-to-surface, and sea-to-air calibration modes. Antenna operational parameter settings include signal waveform, frequency, pulse width, instantaneous bandwidth, gate, gain, range range, and transmit power. Antenna scanning parameter settings include scanning mode, scanning speed, and scanning period. Scanning modes include horizontal omnidirectional scanning, sector scanning, and directional staring, as well as the antenna azimuth, such as elevation azimuth and horizontal azimuth. Processing parameter settings include signal processing parameters and data processing parameters, such as sea clutter threshold, constant false alarm rate (CFAR), detection window, guard window, scanning algorithm parameters, and tracking algorithm parameters. Status reporting configuration includes the ability to configure the status reporting period for each band.

[0057] Figure 4 A flowchart illustrating the measurement of radar cross-section according to an embodiment of the present invention is shown schematically. Figure 4 As shown, when the ship to be measured is located on the ship's rotating platform, the steps of operating S230 to control the UAV to measure the ship to be measured at the i-th pitch angle and multiple azimuth angles and obtain multiple radar cross sections (RCS) include operating S410 to operating S420.

[0058] When operating the S410, the ship's rotating platform is controlled to rotate via a remote operating platform to generate multiple azimuth angles between the UAV and the ship to be measured.

[0059] The remote operation platform sends a rotation command to the ship's rotation platform, controlling the platform to rotate 360°. While the UAV remains in its current hovering position, the ship's rotation platform causes the ship to be measured to rotate 360° together. This means that during the ship's rotation, the UAV is located in multiple positions relative to the ship, creating multiple azimuth angles between the UAV and the ship.

[0060] By operating the S420, the UAV is controlled to measure the ship under test at the i-th pitch angle and multiple azimuth angles, and multiple RCSs are obtained.

[0061] During the measurement process, the radar transmits electromagnetic waves towards the ship being measured and receives the reflected echoes. For the same ship attitude at the same pitch angle, the radar will complete at least 100 beam transmissions and receptions to reduce measurement errors. For each pitch angle, after the ship's rotating platform completes a 360° rotation, the UAV will move to the next hovering position, causing the radar on the UAV to rotate around the ship's rotating platform as the center, forming the next pitch angle.

[0062] Combination Figure 1 The initial hovering position of the UAV can be located to the side of the vessel being measured and at the same horizontal level as the vessel, or it can be considered to be on the sea surface to the side of the vessel. During the movement to the next hovering position, the UAV gradually moves upwards towards the vessel while maintaining a fixed distance, until it is directly above the vessel. When the UAV is directly above the vessel, the line connecting the UAV and the vessel is perpendicular to the sea surface. Ideally, the figure formed by connecting any two hovering points and the position point of the vessel in the UAV's movement trajectory is perpendicular to the sea surface.

[0063] As the UAV gradually moves from the sea level to directly above the vessel being measured, the UAV radar's pitch angle towards the vessel can be considered to gradually increase from 0° to 90°. Conversely, as the UAV gradually moves from directly above the vessel away from its initial hovering position, the pitch angle can be considered to gradually increase from 90° back to 0°. Therefore, the pitch angle produced during the process of the UAV gradually moving from the sea level to directly above the vessel is the same as the pitch angle produced during the process of the UAV gradually moving away from its initial hovering position. To reduce the number of measurement steps, the RCS measurement can be performed during the process of the UAV gradually moving from the sea level to directly above the vessel.

[0064] In this embodiment of the invention, the pitch angle range can be divided into multiple pitch angles. For example, the pitch angles include 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, and 90°, where N = 10. When N = 1, the first pitch angle is 0°. When N = 10, the tenth pitch angle is 90°. Exemplarily, while maintaining a fixed distance from the vessel to be measured, the UAV is controlled to change its pitch angle in 5° increments.

[0065] In this embodiment of the invention, after receiving radar echo data, the radar data is transmitted to a remote operation platform. The remote operation platform performs parameter calculations on the transmitted data to obtain the RCS result of a single-step measurement.

[0066] In this embodiment of the invention, the radar output data includes target data, channel waveform data, and target RCS data. For example, the target data includes target batch number, air-sea attributes, target radial length, longitude, latitude, altitude, heading, and speed.

[0067] Figure 5 A flowchart illustrating the calibration of the pitch angle according to another embodiment of the present invention is shown.

[0068] like Figure 5 As shown, the ship to be measured is located on the ship's rotating platform. The steps of operating S220 to calibrate the pitch angle between the UAV and the ship to be measured in the hovering position include operating S510 to S540.

[0069] When operating the S510, the hovering position of the UAV is calibrated based on the relative position between the UAV and the vessel to be measured.

[0070] When operating the S520, the drone's nose direction is calibrated based on the communication information between the drone and the ship's rotating platform.

[0071] Alignment sensors are installed on the ship's rotating platform, and laser sensors are installed on the drone. Using the laser and alignment sensors, the drone's nose is adjusted to align with the ship to be measured.

[0072] Using the S530, the measured distance between the UAV and the vessel to be measured, as well as the UAV's flight altitude, are obtained after calibration.

[0073] When operating the S540, the pitch angle is calculated based on the measured distance and flight altitude.

[0074] In this embodiment of the invention, the pitch angle of the UAV relative to the ship being measured is determined by measuring the distance between the UAV and the ship being measured and the flight altitude of the UAV.

[0075] Combination Figure 1 The relationship between the measurement distance between the UAV and the vessel under test, the flight altitude of the UAV, and the pitch angle can be expressed by the following relationship: Where H is the flight altitude of the UAV, and R is the measurement distance between the UAV and the ship to be measured. The pitch angle to be measured is denoted as .

[0076] The measurement distance R between the UAV and the vessel under measurement can be preset and executed via a remote operation platform, ensuring a constant measurement distance R between the UAV and the vessel. After acquiring the real-time flight altitude of the calibrated UAV, the current pitch angle of the UAV relative to the vessel can be determined. To further refine the pitch angle, the pointing angle of the radar can be adjusted via the pitch angle controller onboard the UAV.

[0077] Based on the aforementioned method for measuring the RCS of ships, this invention also provides a device for measuring the radar cross-section of ships. The following will combine... Figure 6 The device is described in detail.

[0078] Figure 6 A schematic block diagram of a device for measuring the radar cross-section of a ship according to an embodiment of the present invention is shown.

[0079] like Figure 6 As shown, the ship radar cross-section measuring device 600 of this embodiment includes a control module 610, a calibration module 620, a measurement module 630, and a movement module 640.

[0080] The control module 610 is used to control the drone to reach the i-th hovering position via a remote operation platform, where i ∈ [1, N), and N is a positive integer greater than 1. In one embodiment, the control module 610 can be used to perform the operation S210 described above, which will not be repeated here.

[0081] The calibration module 620 is used to calibrate the i-th pitch angle between the UAV and the vessel to be measured at the i-th hovering position. In one embodiment, the calibration module 620 may be used to perform the operation S220 described above, which will not be repeated here.

[0082] The measurement module 630 is used to measure the ship under test using a UAV at the i-th pitch angle and multiple azimuth angles to obtain multiple radar cross sections (RCS). In one embodiment, the measurement module 630 can be used to perform the operation S230 described above, which will not be repeated here.

[0083] The mobility module 640 is used to control the drone to move from the i-th hovering position to the (i+1)-th hovering position via a remote operation platform. In one embodiment, the mobility module 640 can be used to perform the operation S240 described above, which will not be repeated here.

[0084] According to embodiments of the present invention, any plurality of modules among the control module 610, calibration module 620, measurement module 630, and movement module 640 may be combined into one module, or any one of these modules may be split into multiple modules. Alternatively, at least a portion of the functionality of one or more of these modules may be combined with at least a portion of the functionality of other modules and implemented in one module. According to embodiments of the present invention, at least one of the control module 610, calibration module 620, measurement module 630, and movement module 640 may be at least partially implemented as hardware circuitry, such as a field-programmable gate array (FPGA), a programmable logic array (PLA), a system-on-a-chip, a system-on-a-substrate, a system-on-package, an application-specific integrated circuit (ASIC), or any other reasonable means of integrating or packaging circuitry, or implemented in software, hardware, or firmware, or in any suitable combination of any of these three implementation methods. Alternatively, at least one of the control module 610, calibration module 620, measurement module 630, and movement module 640 may be at least partially implemented as a computer program module, which, when run, can perform corresponding functions. For example, the control module 610, calibration module 620, measurement module 630, and movement module 640 can all be installed in a remote operation platform.

[0085] This invention also provides a system for measuring the radar cross section (RCS) of a ship. The system comprises an unmanned aerial vehicle (UAV), a ship rotation platform, and a remote operation platform. The remote operation platform controls the UAV and the ship rotation platform to perform the ship RCS measurement method described in the above embodiments.

[0086] Figure 7 A block diagram of an electronic device suitable for implementing a method for measuring the radar cross-section of a ship according to an embodiment of the present invention is shown schematically.

[0087] like Figure 7 As shown, an electronic device 700 according to an embodiment of the present invention includes a processor 701, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 702 or a program loaded from a storage portion 708 into a random access memory (RAM) 703. The processor 701 may include, for example, a general-purpose microprocessor (e.g., a CPU), an instruction set processor and / or an associated chipset and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor 701 may also include onboard memory for caching purposes. The processor 701 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present invention.

[0088] RAM 703 stores various programs and data required for the operation of electronic device 700. Processor 701, ROM 702, and RAM 703 are interconnected via bus 704. Processor 701 executes various operations of the method flow according to embodiments of the present invention by executing programs in ROM 702 and / or RAM 703. It should be noted that the programs may also be stored in one or more memories other than ROM 702 and RAM 703. Processor 701 may also execute various operations of the method flow according to embodiments of the present invention by executing programs stored in said one or more memories.

[0089] According to an embodiment of the present invention, the electronic device 700 may further include an input / output (I / O) interface 705, which is also connected to a bus 704. The electronic device 700 may also include one or more of the following components connected to the I / O interface 705: an input section 706 including a keyboard, mouse, etc.; an output section 707 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 708 including a hard disk, etc.; and a communication section 709 including a network interface card such as a LAN card, modem, etc. The communication section 709 performs communication processing via a network such as the Internet. A drive 710 is also connected to the I / O interface 705 as needed. A removable medium 711, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on the drive 710 as needed so that computer programs read from it can be installed into the storage section 708 as needed.

[0090] The present invention also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments; or it may exist independently and not assembled into the device / apparatus / system. The computer-readable storage medium carries one or more programs, which, when executed, implement the method according to the embodiments of the present invention.

[0091] According to embodiments of the present invention, a computer-readable storage medium may be a non-volatile computer-readable storage medium, such as including, but not limited to: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In the present invention, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. For example, according to embodiments of the present invention, a computer-readable storage medium may include ROM 702 and / or RAM 703 and / or one or more memories other than ROM 702 and RAM 703 described above.

[0092] Embodiments of the present invention also include a computer program product comprising a computer program containing program code for performing the methods shown in the flowchart. When the computer program product is run on a computer system, the program code enables the computer system to implement the method for measuring the radar cross-section of a ship provided in the embodiments of the present invention.

[0093] When the computer program is executed by the processor 701, it performs the functions defined in the system / apparatus of this invention. According to embodiments of the invention, the systems, apparatuses, modules, units, etc., described above can be implemented by computer program modules.

[0094] In one embodiment, the computer program may rely on a tangible storage medium such as an optical storage device or a magnetic storage device. In another embodiment, the computer program may also be transmitted and distributed in the form of signals over a network medium, and may be downloaded and installed via the communication section 709, and / or installed from a removable medium 711. The program code contained in the computer program can be transmitted using any suitable network medium, including but not limited to: wireless, wired, etc., or any suitable combination thereof.

[0095] In such an embodiment, the computer program can be downloaded and installed from a network via the communication section 709, and / or installed from the removable medium 711. When the computer program is executed by the processor 701, it performs the functions defined in the system of this embodiment of the invention. According to embodiments of the invention, the systems, devices, apparatuses, modules, units, etc., described above can be implemented by computer program modules.

[0096] According to embodiments of the present invention, program code for executing the computer programs provided in the embodiments of the present invention can be written in any combination of one or more programming languages. Specifically, these computational programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, languages ​​such as Java, C++, Python, "C", or similar programming languages. The program code can be executed entirely on the user's computing device, partially on the user's device, partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0097] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0098] Those skilled in the art will understand that the features described in the various embodiments of the present invention can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention can be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.

[0099] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A method for measuring the radar cross-section of a ship, comprising: The drone is controlled by a remote operation platform to reach the i-th hovering position, where i∈[1,N), and N is a positive integer greater than 1; Calibrate the i-th pitch angle between the UAV and the ship to be measured at the i-th hovering position; The vessel to be measured is located on a rotating platform. The calibration of the i-th pitch angle between the UAV and the ship to be measured at the i-th hovering position includes: The hovering position of the UAV is calibrated based on the relative position between the UAV and the vessel to be measured. The nose direction of the UAV is calibrated based on the communication information between the UAV and the ship's rotating platform. Obtain the calibrated distance between the UAV and the vessel under test, and the flight altitude of the UAV; and The pitch angle is calculated based on the measured distance and the flight altitude; The UAV measures the vessel under test at the i-th pitch angle and multiple azimuth angles to obtain multiple radar cross sections (RCS), including: The remote operation platform controls the rotation of the ship's rotating platform to generate multiple azimuth angles between the UAV and the ship to be measured; and The UAV is controlled to measure the ship under the i-th pitch angle and the multiple azimuth angles to obtain multiple RCSs; The remote operation platform controls the drone to move from the i-th hovering position to the (i+1)-th hovering position.

2. The measurement method according to claim 1, wherein, The UAV includes a laser sensor, radar, and pitch controller. The calibration of the i-th pitch angle between the UAV and the vessel to be measured at the i-th hovering position includes: If the current position of the UAV is determined to be the i-th hovering position, the attitude of the UAV is adjusted according to the feedback information from the laser sensor to align the radar with the ship to be measured; and The pitch controller calibrates the i-th pitch angle of the radar of the UAV in the given attitude.

3. The measurement method according to claim 2, wherein, The pitch controller includes a servo motor and a gyroscope. The step of calibrating the i-th pitch angle of the radar of the UAV in the given attitude using the pitch controller includes: Adjust the rotation angle of the servo motor so that the feedback parameters of the gyroscope are preset parameters, which correspond to the i-th pitch angle.

4. The measurement method according to claim 1, wherein, Before controlling the drone to reach the i-th hovering position via the remote operation platform, the method further includes: initializing the remote operation platform. The initialization of the remote operation platform includes: clearing the PID parameters and loading control commands.

5. The measurement method according to claim 2, wherein, The pitch controller includes a feedback controller, which measures the vessel under test at the i-th pitch angle and multiple azimuth angles using the UAV to obtain multiple radar cross sections (RCS), including: While keeping the i-th pitch angle constant under the control of the UAV through the feedback controller, the UAV is controlled to transmit electromagnetic wave signals to the ship under test through the radar at multiple azimuths of the ship under test; The radar receives the reflected echo signal of the electromagnetic wave; and The reflected echo signal is sent to the remote operation platform by a drone, resulting in multiple RCSs.

6. The measurement method according to claim 5, wherein, The radar's control interface includes operating control commands, mode setting commands, antenna operating parameter settings, antenna scanning parameter settings, processing parameter settings, and reporting status configuration.

7. A device for measuring the radar cross-section of a ship, comprising: The control module is used to control the drone to reach the i-th hovering position through a remote operation platform, where i∈[1,N), and N is a positive integer greater than 1; A calibration module is used to calibrate the i-th pitch angle between the UAV and the vessel to be measured at the i-th hovering position; wherein the vessel to be measured is located on a ship rotation platform; calibrating the i-th pitch angle between the UAV and the vessel to be measured at the i-th hovering position includes: calibrating the hovering position of the UAV based on the relative position between the UAV and the vessel to be measured; calibrating the nose direction of the UAV based on communication information between the UAV and the ship rotation platform; obtaining the measurement distance between the UAV and the vessel to be measured and the flight altitude of the UAV after calibration; and calculating the pitch angle based on the measurement distance and the flight altitude; The measurement module is used to measure the vessel under test by the UAV at the i-th pitch angle and multiple azimuth angles to obtain multiple radar cross sections (RCS), including: controlling the rotation of the vessel rotation platform through the remote operation platform to generate multiple azimuth angles between the UAV and the vessel under test; and controlling the UAV to measure the vessel under test at the i-th pitch angle and the multiple azimuth angles to obtain multiple RCSs; A mobile module is used to control the drone to move from the i-th hovering position to the (i+1)-th hovering position via the remote operation platform.

8. A system for measuring the radar cross-section of a ship, comprising: Drones; Ship rotation platform; A remote operation platform for controlling the UAV and the ship rotation platform to perform the method for measuring the ship's radar cross-section according to any one of claims 1-6.

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