Radar beam compensation method and device based on motion feedforward and detection tracking system

Abstract

The application discloses a radar beam compensation method and device based on motion feedforward and a detection tracking system. The method introduces a real-time beam phase compensation mechanism based on the feedforward of turntable motion information, takes the azimuth rotation of the turntable as a known and measurable input disturbance, actively and feedforwardly compensates the radar beam in reverse, and thus ensures the stable pointing of the radar beam to the target in the inertial space in the whole process of the motion of the turntable, and finally ensures that the target track information is not lost when the radar guides the optical camera to search for the target.

Description

Technical Field

[0001] This application relates to the field of target search and tracking technology, and in particular to a radar beam compensation method, device and detection and tracking system based on motion feedforward. Background Technology

[0002] With the increasing demands for target detection and identification capabilities in modern defense systems and security monitoring, single sensors are no longer sufficient to meet the mission requirements in complex scenarios. Radar has the advantages of long range and all-weather, all-time operation, but it has limitations in the identification and imaging of fine target features. Optical cameras (including infrared and visible light) have extremely high angular resolution and intuitive image information, but their performance degrades under adverse weather conditions, and their relatively short range makes them unsuitable for wide-area target search and early warning missions. Therefore, integrating radar and optical sensors onto the same platform to form a complementary and collaborative detection system has become the mainstream direction of current technological development.

[0003] In such collaborative systems, a "radar coarse guidance, electro-optical fine tracking" working mode is typically adopted. That is, the radar first conducts a wide-area search to find potential threat targets, then performs preliminary tracking and transmits the obtained rough target azimuth, elevation, and distance information to the optical camera. Based on this information, the optical camera directs its field of view toward the target's airspace, and uses image processing technology to perform a fine search and capture of the target within a smaller field of view, before switching to a high-precision image tracking mode.

[0004] However, the effectiveness of this cooperative mode heavily relies on the radar's ability to provide continuous, stable, and high-precision target indication during the guidance and switching process. When a two-dimensional phased-array radar is mounted on a turntable capable of azimuth rotation (the turntable's two-dimensional rotation only drives the radar's azimuth rotation, while its elevation rotation is only provided to the optical camera), a key technical challenge arises: during the process of the two-dimensional phased-array radar guiding the optical camera to acquire the target and the optical camera maintaining tracking after target acquisition, the turntable needs to continuously perform azimuth movement to adjust the optical camera's pointing to keep the target within the optical camera's narrow field of view. For a two-dimensional phased-array radar rigidly connected to the turntable, this movement of the turntable is essentially an imposed "disturbance." Without compensation, the radar beam's pointing in inertial space will change rapidly with the turntable's rotation, causing the target to quickly deviate from the radar beam's main lobe, resulting in echo signal attenuation, deterioration of measurement accuracy, and ultimately, loss of target track. Once the radar track is lost, the optical camera loses guidance information, making it extremely difficult to re-search for a small, distant target in a vast airspace, and the entire cooperative tracking chain breaks down.

[0005] Therefore, how to maintain stable target tracking by a two-dimensional phase-scanning radar under such dynamic platform conditions and ensure seamless transmission of guidance information has become a technical bottleneck that must be overcome to improve the reliability and performance of such radar-electro-optical cooperative systems. Summary of the Invention

[0006] The main objective of this application is to introduce a real-time beam phase compensation mechanism based on turntable motion information feedforward. The azimuth rotation of the turntable is treated as a known and measurable input disturbance. The radar beam is actively and feedforward electronically to perform reverse compensation, thereby ensuring the stable pointing of the radar beam to the target in inertial space throughout the entire turntable motion process. Ultimately, this ensures that the target trajectory information is not lost when the radar guides the optical camera to search for the target.

[0007] To achieve the above objectives, this application proposes a radar beam compensation method based on motion feedforward, applied to a detection and tracking system in which a two-dimensional phase-scanning radar and an optoelectronic imaging device are mounted on the same turntable and work together, including the following steps:

[0008] Real-time acquisition of the target turntable's motion parameters;

[0009] Based on a preset unified spatiotemporal reference, the first measurement data from the target two-dimensional phase-scanning radar and the turntable motion parameters are spatiotemporally synchronized.

[0010] Based on the first measurement data after spatiotemporal synchronization, the first state estimation of the tracked target is performed to obtain the target's predicted position at the target time.

[0011] Based on the predicted target position and the motion parameters after spatiotemporal synchronization, the radar beam pointing of the target's two-dimensional phase-scanning radar is compensated to obtain a beam pointing command.

[0012] According to the beam pointing command, the required phase offset of each radiating element of the phased array antenna corresponding to the target two-dimensional phase-scanned radar is calculated and sent down to complete the radar beam compensation at the target time.

[0013] After the phase offset is acquired, second measurement data from the target two-dimensional phase-scanning radar is obtained, and target measurement values ​​of the tracked target are obtained based on the second measurement data.

[0014] The tracking residual between the target measurement value and the target predicted position is calculated, and based on the tracking residual, a second state estimate of the tracked target is performed, the target predicted position at the next target time is updated, and radar beam compensation is performed at the next target time, until the tracking of the tracked target ends.

[0015] In one embodiment, the turntable motion parameters include azimuth angle, pitch angle, azimuth angular velocity, and pitch angular velocity. A method for real-time acquisition of the turntable motion parameters of the target turntable includes:

[0016] The azimuth and pitch angles are measured in real time by an angle encoder preset on the target turntable, and the azimuth and pitch angular velocities are measured in real time by angle difference calculation or by a gyroscope preset on the target turntable.

[0017] The azimuth, pitch, azimuth angular velocity, and pitch angular velocity obtained in real time are encapsulated together with a unified timestamp into a target platform motion information packet as the turntable motion parameters.

[0018] In one embodiment, the unified spatiotemporal reference includes three coordinate systems: an inertial coordinate system, a turntable coordinate system, and a two-dimensional phase-scanned radar antenna coordinate system, as well as a preset reference clock signal. Based on the preset unified spatiotemporal reference, a method for spatiotemporally synchronizing the first measurement data from the target two-dimensional phase-scanned radar and the turntable motion parameters includes:

[0019] Acquire three predefined coordinate systems and a preset reference clock signal;

[0020] Based on the reference clock signal, a unified time tag is applied to the first measurement data and the turntable motion parameters;

[0021] Interpolate or extrapolate the first measurement data and turntable motion parameters based on the time stamp to unify the first measurement data and turntable motion parameters to the same target time. .

[0022] In one embodiment, the inertial coordinate system uses the Northeast-Upper-High (ENU) or Northeast-East-Earth (NED) coordinate system as a reference.

[0023] The coordinate system of the turntable Origin t Located at the center of rotation of the turntable, The axis points towards the zero position of the turntable. The axis points upwards. The axis is determined by the right-hand rule;

[0024] The coordinate system of the two-dimensional phase-scanning radar antenna Origin O r Located at the radar phase center, X r Axis, Y r Axis and Z r The three axes are parallel to the coordinate system of the turntable.

[0025] In one embodiment, a method for obtaining the predicted target position at a given time by performing a first state estimation of the tracked target based on the first measurement data after spatiotemporal synchronization includes:

[0026] Get the previous target time At that time, the best estimated azimuth angle of the tracked target in the radar coordinate system and best estimated pitch angle ;

[0027] Based on the best estimated azimuth angle and best estimated pitch angle The previous target time The target is pointed at, and the coordinates are transformed from the radar coordinate system to the inertial coordinate system to obtain the previous target time. At the same time, track the target's true azimuth angle in the inertial coordinate system. and the true pitch angle The corresponding relationship is as follows:

[0028] ;

[0029] ;

[0030] in, The azimuth angle of the target turntable, acquired in real time at the previous target moment. The pitch angle of the target turntable, which is collected in real time at the previous target moment;

[0031] According to the true azimuth angle and the true pitch angle The tracking filtering algorithm is used to predict the target's position in the inertial coordinate system at the target time, including the predicted azimuth angle. and predicted pitch angle The target predicted location.

[0032] In one embodiment, a method for compensating the radar beam pointing of a two-dimensional phase-scanning radar of a target based on the predicted target position and the spatiotemporally synchronized motion parameters to obtain a beam pointing command includes:

[0033] Obtain the target time from the motion parameters after spatiotemporal synchronization. Real-time azimuth angle of the target turntable and real-time pitch angle ;

[0034] According to real-time azimuth angle and real-time pitch angle For predicted azimuth angle and predicted pitch angle Compensation is performed to obtain the command azimuth angle corresponding to the beam pointing command. and command pitch angle The compensation formula is as follows:

[0035] ;

[0036] .

[0037] In one embodiment, a method for calculating and transmitting the required phase offset for each radiating element of the phased array antenna corresponding to the target's two-dimensional phase-scanned radar according to the beam pointing command, thereby completing radar beam compensation at the target time, includes:

[0038] The operating wavelength of the target two-dimensional phase-scanning radar Number of rows m, number of columns n, row spacing dx, and column spacing dy;

[0039] According to the operating wavelength Number of rows m, number of columns n, row spacing dx and column spacing dy, command azimuth angle and command pitch angle Calculate the required phase offset for each radiating element of the phased array antenna corresponding to the target two-dimensional phased radar. The corresponding calculation formula is as follows:

[0040] ;

[0041] Based on phase offset The corresponding phase control command is generated and sent to the phase shifter of each radiation unit to complete the radar beam compensation at the target time.

[0042] In one embodiment, it further includes:

[0043] Based on the motion characteristics of the target turntable and the tracking residual, determine the current motion state of the target turntable;

[0044] When the target turntable is currently in a highly maneuverable state, compensation is made for the state estimation parameters or radar beam compensation.

[0045] Furthermore, to achieve the above objectives, this application also proposes a radar beam compensation device based on motion feedforward, comprising:

[0046] The turntable motion parameter sensing module is used to collect the turntable motion parameters of the target turntable in real time.

[0047] The spatiotemporal synchronization and coordinate transformation module is used to perform spatiotemporal synchronization of the first measurement data from the target two-dimensional phase-scanning radar and the turntable motion parameters based on a preset unified spatiotemporal reference.

[0048] The target state prediction and filtering module is used to perform first state estimation of the tracked target based on the first measurement data after spatiotemporal synchronization, and to obtain the target prediction position at the target time.

[0049] The beam phase compensation calculation module is used to compensate the radar beam pointing of the target's two-dimensional phase-scanning radar based on the target's predicted position and the motion parameters after spatiotemporal synchronization, and to obtain the beam pointing command.

[0050] The radar digital beamforming module is used to calculate and transmit the required phase offset of each radiating element of the phased array antenna corresponding to the target two-dimensional phase-scanned radar according to the beam pointing command, so as to complete the radar beam compensation at the target time.

[0051] The closed-loop control module is used to acquire second measurement data from the target two-dimensional phase-scanning radar after the phase offset is executed, and to obtain the target measurement value of the tracked target based on the second measurement data.

[0052] In addition, the target state prediction and filtering module is also used to calculate the tracking residual between the target measurement value and the target prediction position, and to perform a second state estimation of the tracked target based on the tracking residual, and update the target prediction position at the next target time.

[0053] The beam phase compensation calculation module and the radar digital beamforming module are also used to perform radar beam compensation for the next target moment until the tracking of the target ends.

[0054] In addition, to achieve the above objectives, this application also proposes a tracking system, including a two-dimensional phase-scanning radar, an optoelectronic imaging device, and a turntable. The two-dimensional phase-scanning radar and the optoelectronic imaging device are mounted on the turntable and work together, and the system also includes the device described above.

[0055] The radar beam compensation method based on motion feedforward provided in this application adopts the method of direct measurement of turntable motion parameters and feedforward compensation of platform motion. Therefore, it can almost real-time (only limited by data acquisition and calculation delay) offset the influence of turntable motion on radar beam pointing, making the compensation response speed much faster than the traditional pure feedback target tracking filter, and can effectively cope with highly maneuverable turntable motion.

[0056] It adopts a purely electronic and algorithmic solution, which eliminates the need for complex mechanical stabilization mechanisms. Therefore, while achieving high performance, it has the advantages of simplified system structure, reduced size and weight, improved reliability and reduced manufacturing costs.

[0057] By unifying coordinates and performing closed-loop correction, platform motion, target motion, and radar beam control are processed under a precise mathematical model, thus ensuring the accuracy of radar beam compensation and the continuity of target trajectory. Attached Figure Description

[0058] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0059] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0060] Figure 1 This is a flowchart illustrating an embodiment of the radar beam compensation method based on motion feedforward in this application.

[0061] Figure 2 This is a schematic diagram of a structure provided for an embodiment of the radar beam compensation device based on motion feedforward in this application.

[0062] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0063] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0064] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0065] While existing radar beam compensation methods can improve radar performance, they have fundamental limitations in this collaborative scenario. These methods can be broadly categorized into two types: one focuses on improving radar data quality, such as motion compensation for Doppler beam sharpening and synthetic aperture radar imaging, which improves image resolution and focus by compensating for aircraft motion errors, or addresses echo cross-cell migration issues caused by high-speed platforms; the other uses mechanical methods to isolate disturbances, such as antenna stabilization platforms based on inertial elements, which use servo systems to control the platform's reverse movement to maintain stable antenna beam pointing.

[0066] However, these traditional methods were designed to optimize the radar's independent detection, imaging performance, or mechanical stability, without prioritizing "maintaining seamless guidance of another optical sensor." Therefore, they lack a closed-loop control mechanism for the dynamic coordination between radar beam pointing and the field of view of the photoelectric sensor during continuous turntable maneuvers. Specifically, imaging compensation methods based on posterior data processing have inherent delays, failing to meet the real-time requirements for guidance switching; while mechanically stabilized platform solutions are structurally complex, have limited response, and fail to fully utilize the beam agility of electronically scanned radar. Essentially, existing technologies solve the single problem of radar "seeing clearly" or "pointing steadily," but fail to guarantee sufficient continuity and stability of the pointing information output by the radar as a guidance source on dynamic platforms to ensure that the photoelectric sensor can reliably acquire and lock onto the target, thus making the entire cooperative tracking link process prone to interruption.

[0067] To address the aforementioned issues, this application acquires platform motion parameters such as azimuth, elevation, angular velocity, and angular acceleration reported by the turntable in real time. Combined with the radar's own measurement data of the target, under a unified spatiotemporal reference, it accurately calculates and predicts the change in the target's relative position caused by platform motion. Subsequently, this change is converted into beam control phase codes required by the two-dimensional phase-scanning radar. The radar's digital beamforming network dynamically compensates for the pointing of the transmitted and received beams, thereby offsetting the influence of platform motion and ensuring that the radar beam is always stably pointing at the target in space, providing reliable data guidance for the optical camera to successfully acquire the target.

[0068] Based on this, embodiments of this application provide a radar beam compensation method based on motion feedforward, applied to a detection and tracking system in which a two-dimensional phase-scanning radar and an optoelectronic imaging device are mounted on the same turntable and work together, referring to... Figure 1 This includes the following steps:

[0069] Step S1: Real-time acquisition of the turntable motion parameters of the target turntable;

[0070] Step S2: Based on a preset unified spatiotemporal reference, the first measurement data from the target two-dimensional phase-scanning radar and the turntable motion parameters are spatiotemporally synchronized.

[0071] Step S3: Based on the first measurement data after spatiotemporal synchronization, perform the first state estimation of the tracking target to obtain the target's predicted position at the target time.

[0072] Step S4: Based on the predicted target position and the motion parameters after spatiotemporal synchronization, compensate the radar beam pointing of the target's two-dimensional phase-scanning radar to obtain a beam pointing command.

[0073] Step S5: According to the beam pointing command, calculate the required phase offset of each radiating element of the phased array antenna corresponding to the target two-dimensional phase-scanned radar and send it down to complete the radar beam compensation at the target time.

[0074] Step S6: After the phase offset is executed, obtain the second measurement data from the target two-dimensional phase-scanning radar, and obtain the target measurement value of the tracked target based on the second measurement data;

[0075] Step S7: Calculate the tracking residual between the target measurement value and the target predicted position, and based on the tracking residual, perform a second state estimation of the tracked target, update the target predicted position at the next target time, and perform radar beam compensation at the next target time until the tracking of the tracked target ends.

[0076] In this embodiment, a two-dimensional phase-scanning radar refers to a phased array radar that can perform beam scanning in both azimuth and elevation dimensions electronically. Its core is an array composed of multiple antenna elements. By controlling the phase of the transmitted or received signals of each element, the beam can be scanned rapidly in space without inertia. The target two-dimensional phase-scanning radar is a two-dimensional phase-scanning radar that requires radar beam compensation.

[0077] Radar track information refers to a time-series data set that describes the target's motion state (including position, velocity, acceleration, etc.) formed by radar through multiple measurements. The track line of the target's motion is generated on the software interface. The continuity of the track is the basis for stable tracking. Both the first and second measurement data come from radar track information.

[0078] Beam phase compensation is a technique in phased array radar that corrects or cancels beam pointing errors caused by external factors (such as platform motion, atmospheric refraction, etc.) by adjusting the phase offset of each antenna element in real time.

[0079] Digital beamforming (DBF) is a signal processing technique that forms a flexible, adaptive receive beam by weighting (including amplitude and phase) the signals received by each antenna channel in the digital domain.

[0080] The turntable motion parameters, including azimuth, pitch, azimuth rate, and pitch rate, will be used as known feedforward quantities and directly participate in the calculation of the radar beam pointing angle. The phase of the beam control will be dynamically corrected in real time, thereby physically offsetting the influence of the platform motion, so as to ultimately ensure that the target track information is not lost when the radar guides the optical camera to search for the target.

[0081] A unified spatiotemporal reference includes a unified coordinate system and a unified time label. The first measurement data and turntable motion parameters of spatiotemporal synchronization will be strictly aligned to the same point in time to ensure data validity.

[0082] After completing the radar beam compensation at the target time, steps S1 to S5 are only an open-loop feedforward control. To further improve robustness, a closed loop is constructed through steps S6 to S7. The tracking residual includes the target maneuver model error, platform motion measurement error, calculation delay error, etc. By feeding this residual back to step S3 to update the target state estimate, the target prediction position at the next target time is more accurate, thus forming a closed loop of "prediction-compensation-measurement-correction".

[0083] In one optional implementation, the turntable motion parameters include azimuth angle, pitch angle, azimuth angular velocity, and pitch angular velocity. Step S1, a method for real-time acquisition of the turntable motion parameters of the target turntable, includes:

[0084] Step S101: Measure the azimuth and pitch angles in real time using an angle encoder preset on the target turntable, and measure the azimuth and pitch angular velocities in real time using angle difference calculation or a gyroscope preset on the target turntable.

[0085] Step S102: Encapsulate the azimuth angle, pitch angle, azimuth angular velocity and pitch angular velocity obtained in real time with a unified timestamp into a target platform motion information packet as the turntable motion parameters.

[0086] In this embodiment, the target platform motion information packets are transmitted via high-speed buses, such as Ethernet and PCIe.

[0087] Further, the unified spatiotemporal reference includes three coordinate systems: an inertial coordinate system, a turntable coordinate system, and a two-dimensional phase-scanned radar antenna coordinate system, as well as a preset reference clock signal. Step S2, a method for spatiotemporally synchronizing the first measurement data from the target two-dimensional phase-scanned radar and the turntable motion parameters based on the preset unified spatiotemporal reference, includes:

[0088] Step S201: Obtain three predefined coordinate systems and a preset reference clock signal;

[0089] Step S202: Based on the reference clock signal, assign a unified time tag to the first measurement data and the turntable motion parameters;

[0090] Step S203: Interpolate or extrapolate the first measurement data and turntable motion parameters according to the time tag, and unify the first measurement data and turntable motion parameters to the same target time. .

[0091] Furthermore, the inertial coordinate system uses the Northeast-Upper-High (ENU) or Northeast-East-Earth (NED) coordinate system as a reference.

[0092] The coordinate system of the turntable Origin t Located at the center of rotation of the turntable, The axis points towards the zero position of the turntable. The axis points upwards. The axis is determined by the right-hand rule;

[0093] The coordinate system of the two-dimensional phase-scanning radar antenna Origin O r Located at the radar phase center, its X r Axis, Y r Axis and Z r The three axes are parallel to the coordinate system of the turntable.

[0094] In this embodiment, spatiotemporal synchronization is crucial to ensuring data validity. Turntable motion parameters and radar measurement data must be strictly aligned to the same point in time. This embodiment uses a unified clock signal to assign a uniform time tag to all input data. During processing, this time tag is used to interpolate or extrapolate the data, unifying it to the same processing time. That is, the target time.

[0095] In an optional implementation, step S3, the method for performing a first state estimation of the tracking target based on the first measurement data after spatiotemporal synchronization to obtain the target's predicted position at the target time, includes:

[0096] Step S301: Obtain the previous target time. At that time, the best estimated azimuth angle of the tracked target in the radar coordinate system and best estimated pitch angle ;

[0097] Step S302: Based on the best estimated azimuth angle and best estimated pitch angle The previous target time The target is pointed at, and the coordinates are transformed from the radar coordinate system to the inertial coordinate system to obtain the previous target time. At the same time, track the target's true azimuth angle in the inertial coordinate system. and the true pitch angle The corresponding relationship is as follows:

[0098] ;

[0099] ;

[0100] in, The azimuth angle of the target turntable, acquired in real time at the previous target moment. The pitch angle of the target turntable, which is collected in real time at the previous target moment;

[0101] Step S303: Based on the true azimuth angle and the true pitch angle The tracking filtering algorithm is used to predict the target's position in the inertial coordinate system at the target time, including the predicted azimuth angle. and predicted pitch angle The target predicted location.

[0102] In this implementation method, firstly, the previous target time is... The target orientation is transformed from the radar coordinate system to the inertial coordinate system. This transformation is performed by the turntable at the previous target time. The attitude is determined by the target's orientation. Specifically, the transformation of a pointing vector in three-dimensional space between the inertial frame and the turntable frame can be achieved using a rotation matrix. The true azimuth angle of the target in the inertial coordinate system can be obtained by directly synthesizing the azimuth and pitch angles. and the true pitch angle ;

[0103] In this embodiment, the tracking filtering algorithm is the Extended Kalman Filter (EKF), which predicts the target's azimuth angle in the inertial coordinate system at the target time. and predicted pitch angle The target's predicted position is used to compensate for the target's maneuvering.

[0104] Further, step S4, the method for compensating the radar beam pointing of the target's two-dimensional phase-scanning radar based on the predicted target position and the spatiotemporally synchronized motion parameters to obtain beam pointing commands, includes:

[0105] Step S401: Obtain the target time from the motion parameters after spatiotemporal synchronization. Real-time azimuth angle of the target turntable and real-time pitch angle ;

[0106] Step S402: Based on the real-time azimuth angle and real-time pitch angle For predicted azimuth angle and predicted pitch angle Compensation is performed to obtain the command azimuth angle corresponding to the beam pointing command. and command pitch angle The compensation formula is as follows:

[0107]

[0108] .

[0109] In this embodiment, since the turntable from arrive The amount of exercise is and ,in Therefore, in order to maintain the same target in inertial space, the direction of the radar beam in the radar coordinate system must be reversed to cancel out this part of the platform's motion.

[0110] Through the transformation method of this implementation, the inverse coordinate transformation from the inertial coordinate system to the radar coordinate system at the current moment is completed. It converts the predicted position of the target in the inertial system into the direction that the radar should be pointing at at the current moment.

[0111] Furthermore, step S5, calculating and transmitting the required phase offset for each radiating element of the phased array antenna corresponding to the target's two-dimensional phase-scanned radar according to the beam pointing command, to complete the radar beam compensation at the target moment, includes:

[0112] Step S501: Obtain the operating wavelength of the target's two-dimensional phase-scanning radar. Number of rows m, number of columns n, row spacing dx, and column spacing dy;

[0113] Step S502: According to the working wavelength Number of rows m, number of columns n, row spacing dx and column spacing dy, command azimuth angle and command pitch angle Calculate the required phase offset for each radiating element of the phased array antenna corresponding to the target two-dimensional phased radar. The corresponding calculation formula is as follows:

[0114] ;

[0115] Step S503: Based on the phase offset The corresponding phase control command is generated and sent to the phase shifter of each radiation unit to complete the radar beam compensation at the target time.

[0116] Using this implementation method, it is possible to calculate all phase offsets. This generates corresponding phase control commands, which are then loaded onto the phase shifters of each antenna element. Thus, in... The radar beam that is formed at any given time has its main lobe pointing precisely to the spatial location after platform motion compensation and target motion prediction.

[0117] In the above implementation, the formula for calculating the tracking residual is as follows:

[0118] ;

[0119] ;

[0120] in, For radar in The system continuously transmits signals in the compensated direction and receives echoes, then obtains new target measurement values ​​through signal processing.

[0121] In one alternative implementation, it further includes:

[0122] Based on the motion characteristics of the target turntable and the tracking residual, determine the current motion state of the target turntable;

[0123] When the target turntable is currently in a highly maneuverable state, compensation is made for the state estimation parameters or radar beam compensation.

[0124] In this embodiment, motion characteristics include the magnitude of angular acceleration, etc., and the setting can be made according to the actual working conditions when determining whether the current motion state of the target turntable is a high-mobility motion.

[0125] Compensating for radar beam compensation can be done by multiplying the radar beam compensation by a gain factor slightly greater than 1 to provide stronger compensation and prevent tracking lag due to model mismatch in high dynamic scenarios.

[0126] Through the above "prediction-compensation-measurement-correction" steps, this invention utilizes the real-time measured turntable azimuth angle and its first and second derivatives (angular velocity and angular acceleration) to directly calculate the radar beam pointing correction amount used to offset the platform motion, and feeds it forward to the beam control command generation stage, realizing accurate and stable tracking of the target by the two-dimensional phase-scanning radar beam under turntable motion conditions, and providing accurate guidance data for the optical camera to search for and capture the target;

[0127] The entire solution makes full use of the parameter information provided in real time by the turntable, and achieves the effect of an inertial stabilization platform in a purely electronic way, solving the problem of the stability of the target trajectory information of the two-dimensional phase-scanning radar during movement.

[0128] In addition, this application also provides an implementation method for a radar beam compensation device based on motion feedforward, such as... Figure 2 As shown, it includes:

[0129] The turntable motion parameter sensing module is used to collect the turntable motion parameters of the target turntable in real time.

[0130] The spatiotemporal synchronization and coordinate transformation module is used to perform spatiotemporal synchronization of the first measurement data from the target two-dimensional phase-scanning radar and the turntable motion parameters based on a preset unified spatiotemporal reference.

[0131] The target state prediction and filtering module is used to perform first state estimation of the tracked target based on the first measurement data after spatiotemporal synchronization, and to obtain the target prediction position at the target time.

[0132] The beam phase compensation calculation module is used to compensate the radar beam pointing of the target's two-dimensional phase-scanning radar based on the target's predicted position and the motion parameters after spatiotemporal synchronization, and to obtain the beam pointing command.

[0133] The radar digital beamforming module is used to calculate and transmit the required phase offset of each radiating element of the phased array antenna corresponding to the target two-dimensional phase-scanned radar according to the beam pointing command, so as to complete the radar beam compensation at the target time.

[0134] The closed-loop control module is used to acquire second measurement data from the target two-dimensional phase-scanning radar after the phase offset is executed, and to obtain the target measurement value of the tracked target based on the second measurement data.

[0135] In addition, the target state prediction and filtering module is also used to calculate the tracking residual between the target measurement value and the target prediction position, and to perform a second state estimation of the tracked target based on the tracking residual, and update the target prediction position at the next target time.

[0136] The beam phase compensation calculation module and the radar digital beamforming module are also used to perform radar beam compensation for the next target moment until the tracking of the target ends.

[0137] In addition, this application also provides embodiments of a detection and tracking system, including a two-dimensional phase-scanning radar, an optoelectronic imaging device, and a turntable. The two-dimensional phase-scanning radar and the optoelectronic imaging device are mounted on the turntable and work together. The system also includes the apparatus described in the above embodiments.

[0138] The above description is only a part of the embodiments of this application and does not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A radar beam compensation method based on motion feedforward, characterized in that, The detection and tracking system, which integrates a two-dimensional phase-scanning radar and an optoelectronic imaging device mounted on the same turntable and working collaboratively, includes the following steps: The turntable motion parameters of the target turntable are collected in real time, including azimuth angle, pitch angle, azimuth angular velocity and pitch angular velocity. Based on a preset unified spatiotemporal reference, the first measurement data from the target two-dimensional phase-scanning radar and the turntable motion parameters are spatiotemporally synchronized, unifying the first measurement data and the turntable motion parameters to the same target time. The unified spatiotemporal reference includes three coordinate systems: an inertial coordinate system, a turntable coordinate system, and a two-dimensional phase-scanned radar antenna coordinate system, as well as a preset reference clock signal. Based on the first measurement data after spatiotemporal synchronization, the first state estimation of the tracked target is performed to obtain the predicted position of the target at the target time, including: Get the previous target time At that time, the best estimated azimuth angle of the tracked target in the radar coordinate system and best estimated pitch angle ; Based on the best estimated azimuth angle and best estimated pitch angle The previous target time The target is pointed at, and the coordinates are transformed from the radar coordinate system to the inertial coordinate system to obtain the previous target time. At the same time, track the target's true azimuth angle in the inertial coordinate system. and the true pitch angle The corresponding relationship is as follows: ； ； in, The azimuth angle of the target turntable, acquired in real time at the previous target moment. The pitch angle of the target turntable, which is collected in real time at the previous target moment; According to the true azimuth angle and the true pitch angle The tracking filtering algorithm is used to predict the target's position in the inertial coordinate system at the target time, including the predicted azimuth angle. and predicted pitch angle The target predicted position, wherein the tracking filtering algorithm is the Extended Kalman Filter (EKF); Based on the predicted target position and the spatiotemporally synchronized motion parameters, the radar beam pointing of the target's two-dimensional phase-scanning radar is compensated to obtain a beam pointing command, including: Obtain the target time from the motion parameters after spatiotemporal synchronization. Real-time azimuth angle of the target turntable and real-time pitch angle ; According to real-time azimuth angle and real-time pitch angle For predicted azimuth angle and predicted pitch angle Compensation is performed to obtain the command azimuth angle corresponding to the beam pointing command. and command pitch angle The compensation formula is as follows: ； ； According to the beam pointing command, the required phase offset of each radiating element of the phased array antenna corresponding to the target two-dimensional phase-scanned radar is calculated and sent down to complete the radar beam compensation at the target time. After the phase offset is acquired, second measurement data from the target two-dimensional phase-scanning radar is obtained, and target measurement values ​​of the tracked target are obtained based on the second measurement data. The tracking residual between the target measurement value and the target predicted position is calculated, and based on the tracking residual, a second state estimate of the tracked target is performed, the target predicted position at the next target time is updated, and radar beam compensation is performed at the next target time, until the tracking of the tracked target ends.

2. The radar beam compensation method based on motion feedforward as described in claim 1, characterized in that, Methods for real-time acquisition of turntable motion parameters of the target turntable include: The azimuth and pitch angles are measured in real time by an angle encoder preset on the target turntable, and the azimuth and pitch angular velocities are measured in real time by angle difference calculation or by a gyroscope preset on the target turntable. The azimuth, pitch, azimuth angular velocity, and pitch angular velocity obtained in real time are encapsulated together with a unified timestamp into a target platform motion information packet as the turntable motion parameters.

3. The radar beam compensation method based on motion feedforward as described in claim 2, characterized in that, A method for spatiotemporally synchronizing first measurement data from a target two-dimensional phase-scanning radar and the turntable motion parameters based on a preset unified spatiotemporal reference includes: Acquire three predefined coordinate systems and a preset reference clock signal; Based on the reference clock signal, a unified time tag is applied to the first measurement data and the turntable motion parameters; Interpolate or extrapolate the first measurement data and turntable motion parameters based on the time stamp to unify the first measurement data and turntable motion parameters to the same target time. .

4. The radar beam compensation method based on motion feedforward as described in claim 3, characterized in that: The inertial coordinate system uses the Northeast-Upper-High (ENU) or Northeast-East-Earth (NED) coordinate system as the reference. The coordinate system of the turntable Origin t Located at the center of rotation of the turntable, The axis points towards the zero position of the turntable. The axis points upwards. The axis is determined by the right-hand rule; The coordinate system of the two-dimensional phase-scanning radar antenna Origin O r Located at the radar phase center, its X r Axis, Y r Axis and Z r The three axes are parallel to the coordinate system of the turntable.

5. The radar beam compensation method based on motion feedforward as described in claim 1, characterized in that, The method for calculating and transmitting the required phase offset for each radiating element of the phased array antenna corresponding to the target's two-dimensional phase-scanned radar, based on the beam pointing command, to complete radar beam compensation at the target moment includes: The operating wavelength of the target two-dimensional phase-scanning radar Number of rows m, number of columns n, row spacing dx, and column spacing dy; According to the operating wavelength Number of rows m, number of columns n, row spacing dx and column spacing dy, command azimuth angle and command pitch angle Calculate the required phase offset for each radiating element of the phased array antenna corresponding to the target two-dimensional phased radar. The corresponding calculation formula is as follows: ； Based on phase offset The corresponding phase control command is generated and sent to the phase shifter of each radiation unit to complete the radar beam compensation at the target time.

6. The radar beam compensation method based on motion feedforward as described in claim 1, characterized in that, Also includes: Based on the motion characteristics of the target turntable and the tracking residual, determine the current motion state of the target turntable; When the target turntable is currently in a highly maneuverable state, compensation is made for the state estimation parameters or radar beam compensation.

7. A radar beam compensation device based on motion feedforward, characterized in that, include: The turntable motion parameter sensing module is used to collect the turntable motion parameters of the target turntable in real time, wherein the turntable motion parameters include azimuth angle, pitch angle, azimuth angular velocity and pitch angular velocity; The spatiotemporal synchronization and coordinate transformation module is used to perform spatiotemporal synchronization of the first measurement data from the target two-dimensional phase-scanning radar and the turntable motion parameters based on a preset unified spatiotemporal reference, unifying the first measurement data and the turntable motion parameters to the same target time. The unified spatiotemporal reference includes three coordinate systems: an inertial coordinate system, a turntable coordinate system, and a two-dimensional phase-scanned radar antenna coordinate system, as well as a preset reference clock signal. The target state prediction and filtering module is used to perform a first state estimation of the tracked target based on the first measurement data after spatiotemporal synchronization, and to obtain the predicted target position at the target time, including: Get the previous target time At that time, the best estimated azimuth angle of the tracked target in the radar coordinate system and best estimated pitch angle ; Based on the best estimated azimuth angle and best estimated pitch angle The previous target time The target is pointed at, and the coordinates are transformed from the radar coordinate system to the inertial coordinate system to obtain the previous target time. At the same time, track the target's true azimuth angle in the inertial coordinate system. and the true pitch angle The corresponding relationship is as follows: ； ； in, The azimuth angle of the target turntable, acquired in real time at the previous target moment. The pitch angle of the target turntable, which is collected in real time at the previous target moment; According to the true azimuth angle and the true pitch angle The tracking filtering algorithm is used to predict the target's position in the inertial coordinate system at the target time, including the predicted azimuth angle. and predicted pitch angle The target predicted position, wherein the tracking filtering algorithm is the Extended Kalman Filter (EKF); The beam phase compensation calculation module is used to compensate the radar beam pointing of the target's two-dimensional phase-scanning radar based on the target's predicted position and the motion parameters after spatiotemporal synchronization, and to obtain beam pointing instructions, including: Obtain the target time from the motion parameters after spatiotemporal synchronization. Real-time azimuth angle of the target turntable and real-time pitch angle ; According to real-time azimuth angle and real-time pitch angle For predicted azimuth angle and predicted pitch angle Compensation is performed to obtain the command azimuth angle corresponding to the beam pointing command. and command pitch angle The compensation formula is as follows: ； ； The radar digital beamforming module is used to calculate and transmit the required phase offset of each radiating element of the phased array antenna corresponding to the target two-dimensional phase-scanned radar according to the beam pointing command, so as to complete the radar beam compensation at the target time. The closed-loop control module is used to acquire second measurement data from the target two-dimensional phase-scanning radar after the phase offset is executed, and to obtain the target measurement value of the tracked target based on the second measurement data. In addition, the target state prediction and filtering module is also used to calculate the tracking residual between the target measurement value and the target prediction position, and to perform a second state estimation of the tracked target based on the tracking residual, and update the target prediction position at the next target time. The beam phase compensation calculation module and the radar digital beamforming module are also used to perform radar beam compensation for the next target moment until the tracking of the target ends.

8. A detection and tracking system, comprising a two-dimensional phase-scanning radar, an optoelectronic imaging device, and a turntable, wherein the two-dimensional phase-scanning radar and the optoelectronic imaging device are mounted on the turntable and work together, characterized in that, It also includes the apparatus as described in claim 7.

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