An airborne phased array telemetry antenna simulation method

Abstract

The application relates to a kind of airborne phased array telemetry antenna simulation methods, from the measured unit level pattern stored in advance, the weighting coefficient of each antenna unit to each signal is loaded in real time, and the weighting coefficient of the whole array is synthesized;The signal of target, interference and multipath is the multi-channel radio frequency analog signal formed by electromagnetic propagation simulation system modulating baseband signal;The multi-channel radio frequency analog signal is collected and filtered by the radio frequency receiving unit of the application.Digitized multi-channel radio frequency signal is calculated by the pattern weighting coefficient in real time, and finally forms multi-target multi-beam output to telemetry baseband.The application realizes the amplitude and phase control of target, multipath and interference based on the measured unit level phased array antenna pattern, and completes the accurate control of the amplitude and phase of each channel signal;Highly restored digital IQ beam well supports equipment training and performance evaluation under complex geographical and electromagnetic environment, and research and verification of airborne telemetry system anti-interference means.

Description

Technical Field

[0001] This invention belongs to the field of airborne phased array telemetry technology, and relates to a simulation method for airborne phased array telemetry antennas. Background Technology

[0002] Airborne telemetry systems, due to the elevated installation platform, can effectively overcome the problems of short line-of-sight and easy obstruction of low-altitude and ultra-low-altitude flying targets caused by the curvature of the earth. In addition, the high maneuverability of the aircraft platform can serve as an important means of filling blind spots in large-scale, long-range tests. Therefore, they are widely used as an important measurement method in the telemetry tests of low-altitude aircraft both domestically and internationally.

[0003] Because the test objects for telemetry (hereinafter referred to as targets) fly at low / ultra-low altitudes, the receiving beam's ground-touching angle is too small when conducting long-distance telemetry above 300 kilometers, resulting in severe multipath propagation. This leads to large fluctuations in the received telemetry signal power, unstable telemetry links, and even the inability to demodulate. Furthermore, some existing ground-based electronic equipment radiates high-power signals in frequencies close to or even directly within the telemetry band, or its harmonics are located within the telemetry band. Therefore, unlike ground-based telemetry systems that can utilize terrain shielding for interference suppression, airborne telemetry systems, when elevated, are susceptible to interference from certain equipment, leading to performance degradation or even malfunction. Therefore, certain interference suppression methods must be employed to ensure the system's normal operation.

[0004] Airborne phased array telemetry antennas, constrained by the aircraft's aerodynamic shape, typically employ rectangular cut arrays with non-uniform radomes. Furthermore, wing reflections cause distortion in the radiation pattern, particularly in the sidelobe gain of the downward-looking portion, resulting in significant discrepancies from theoretical models. In certain situations, such as close-range, high-elevation angles, or when tracking targets with sidelobes, directly applying simple theoretical models can lead to substantial differences from real-world scenarios.

[0005] Constructing a simulation system to perform detailed simulation and analysis of the complex geographical and electromagnetic interference effects in the test environment can effectively support the formulation of mission plans: planning reasonable aircraft routes, telemetry frequencies, telemetry bandwidths, anti-interference methods, and the coordination methods and timing of multiple airborne telemetry systems. Summary of the Invention

[0006] Technical problems to be solved

[0007] To avoid the shortcomings of existing technologies, this invention proposes a method for simulating airborne phased array telemetry antennas. The technical problem to be solved is how to achieve a refined simulation of the phased array antenna of an airborne telemetry system, receive radio frequency analog signals from multiple channels, and output a synthesized digital telemetry IQ signal to the telemetry baseband.

[0008] Technical solution

[0009] A simulation method for an airborne phased array telemetry antenna, characterized in that the simulation system includes a guidance unit, a beam scheduling unit, a radiation pattern calculation unit, an RF receiving unit, and a beamforming unit, and the simulation steps are as follows:

[0010] Step 1: The directing unit sends basic operating parameters to the beam scheduling unit via the network. The beam scheduling unit sends the basic operating parameters to the pattern calculation unit in sequence. At the same time, it reads the pre-stored unit-level measured antenna pattern data for the operating frequency and sends it to the pattern calculation unit.

[0011] The basic operating parameters include the position of each target, the direction of each interference, and the direction of each multipath signal (all in the body coordinate system), which generate beam control words including the direction of each beam, operating frequency, operating bandwidth, interference intensity and direction (in the array coordinate system).

[0012] Step 2: The pattern calculation unit calculates the gain of targets and interference in each beam in real time online, and sends the weighting coefficients of each beam to the beamforming unit.

[0013] The horizontal polarization beam weighting coefficients:

[0014]

[0015] The vertical polarization beam weighting coefficients:

[0016]

[0017] In the formula: N is the number of horizontally polarized / vertically polarized elements in the antenna array, n = 1, ..., D is the target / multipath signal / interference designation, and m = 1, 2, 3 represent the sum, difference, and difference beams. The gain of the horizontal and vertical cell oscillators for all classes of cell patterns stored in DDR; For beam weighting, both values ​​are set to 1 for sum beams, and half of the array is set to 1 and the other half to -1 for difference beams, satisfying the sum and difference angle measurement requirements; d k,x d represents the azimuth distance of the k-th unit from the center of the array; k,y The elevation distance of the k-th unit from the center of the array; The beam control pointing azimuth and elevation angle (in the array coordinate system) transmitted by the telemetry baseband; ρ represents the true azimuth and elevation angle (in array coordinate system) of the nth target / multipath signal / interference transmitted by the guidance unit; ρ is the polarization angle between the horizontal antenna element and the target's projection onto the antenna array plane.

[0018] Step 3: The beamforming unit calculates the simulated horizontal and vertical polarization composite signal based on the beam weighting coefficients.

[0019]

[0020]

[0021] In the formula: s n (t i ) is the radio frequency receiving unit at t i The IQ signal after digitization of the nth target / multipath signal / interference at any given time.

[0022] The acquisition of the unit-level measured antenna pattern data is as follows: the antenna is tested for receiving beamwidth in a microwave anechoic chamber to obtain the pattern data of each unit, and then the antenna pattern data is divided into a certain number of categories according to the similarity of the pattern data of each antenna unit, and the pattern data of each type of antenna unit is stored in the hard disk of the beam scheduling unit.

[0023] The beam scheduling module reads complete radiation pattern data for all frequencies and categories involved in the simulation and loads it into its DDR at once. Before each beam control word is sent, it selects the unit gain values ​​for all categories, corresponding frequencies, and corresponding target / interference / multipath signal azimuth and elevation angles from the radiation pattern data and sends them to the radiation pattern calculation unit.

[0024] The radiation pattern calculation unit, according to the radiation pattern category distribution matrix, restores the gain values ​​of all received class units to the gain values ​​of all units on the entire array, thereby calculating the overall array composite gain.

[0025] The radio frequency receiving unit includes 16 configurable channels and can output 16 IQ signals to the back-end beamforming unit. By configuring and adjusting different digital weighting coefficients through the beamforming unit, different ratios of the number of target, multipath, and interference signals can be obtained, thereby simulating task scenarios with different numbers of single / multi-target, single / multi-interference, and multipath signals.

[0026] Beneficial effects

[0027] This invention proposes a simulation method for airborne phased array telemetry antennas, belonging to the field of airborne phased array telemetry technology. The method includes, based on the operating frequency issued by the guidance system, target, multipath, interference, and inertial navigation data of the carrier platform, loading the weighting coefficients of each antenna element for each signal in real time from a pre-stored measured unit-level radiation pattern, and finally synthesizing the weighting coefficients of the entire array. The target, interference, and multipath signals are multi-channel radio frequency (RF) simulated signals formed by modulating the baseband signal using an electromagnetic propagation simulation system. These multi-channel RF simulated signals are acquired, digitized, and filtered by the RF receiving unit of this invention. The digitized multi-channel RF signals are then processed by real-time calculated radiation pattern weighting coefficients to ultimately form a multi-target, multi-beam output to the telemetry baseband. This invention achieves signal amplitude and phase control of targets, multipath, and interference based on real-time online calculation of the array radiation pattern using measured unit-level phased array antenna radiation patterns, completing precise amplitude and phase control of each signal. Based on highly realistic digital IQ beams, it can effectively support equipment training and performance evaluation in complex geographical and electromagnetic environments, as well as the research and verification of anti-interference measures for airborne telemetry systems.

[0028] The advantages of this invention are:

[0029] 1. High simulation fidelity and good real-time performance. Based on the measured unit-level phased array antenna pattern, this invention uses a high-performance computing platform to calculate the array pattern in real time under the drive of the real-time scenario provided by the guidance unit. This achieves amplitude control of the target, interference, and multipath signals, completing the precise amplitude and phase control of the target, interference, and multipath signal simulation. Compared with traditional modeling and simulation methods, this invention fully considers the non-uniformity and symmetry of the airborne antenna pattern, resulting in higher fidelity and better adaptability to the complexity of airborne platforms.

[0030] 2. Excellent external interface versatility. This invention employs both analog radio frequency (RF) interfaces and gigabit network (GNR) interfaces. Scene parameters, beam control commands, and status data are all transmitted using GNR and UDP protocols. Signals containing complex modulation information, such as target signals, multipath signals, and interference signals, are transmitted using general-purpose analog RF signals, avoiding the extensive testing work required by highly customized methods such as protocol formats and fiber optic rates in digital signal transmission.

[0031] 3. High scenario adaptability. This invention employs a 16-channel RF receiving unit, capable of outputting 16 IQ signals to the back-end beamforming unit. The beamforming unit can adjust the digital weighting to correspond to the quantity ratio of target, multipath, and interference signals, thereby adapting to task scenarios with varying numbers of single / multiple targets, single / multiple interference signals, and multipath signals. Furthermore, the RF receiving unit can adapt to different operating frequencies by controlling and adjusting its digital filters, possessing the capability to adapt to broadband RF.

[0032] 4. Excellent scalability and upgradeability. Since the beam control unit involved in external docking and the pattern calculation unit for complex algorithm models adopt the general-purpose and easily developable X86 and PowerPC platforms, and the parts involving high-speed communication and computation adopt mature and modular FPGAs, the simulation system described in this invention has the advantages of fast development speed, strong platform performance, and excellent scalability and upgradeability.

[0033] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the interface between the airborne phased array telemetry antenna simulation system proposed in this invention and other subsystems;

[0035] Figure 2 This is a connection diagram of the various components of the airborne phased array telemetry antenna simulation system proposed in this invention;

[0036] Figure 3 This is a simulation flowchart of the airborne phased array telemetry antenna simulation system proposed in this invention. Detailed Implementation

[0037] The present invention will now be further described in conjunction with the embodiments and accompanying drawings:

[0038] The present invention solves the above-mentioned technical problems through the following technical means:

[0039] This invention proposes a method for simulating an airborne phased array telemetry antenna, the method comprising:

[0040] The simulation system's tuning unit sends out basic operating parameters, including the operating frequency, via the network. The beam scheduling unit reads the unit-level measured antenna pattern at the corresponding frequency. The pattern data is pre-stored on a local high-capacity hard drive.

[0041] The beam scheduling unit will send the cell-level radiation pattern it reads to the radiation pattern calculation unit;

[0042] The beam scheduling unit receives beam pointing control parameters from the telemetry baseband system, combines them with the interference pointing parameters from the guidance unit, generates beam control words including beam pointing, operating frequency, operating bandwidth, interference, etc., and then sends them to the pattern calculation unit in sequence.

[0043] The radiation pattern calculation unit calculates the gain of targets and interference in each beam in real time online, and sends the beam weighting coefficients of each beam to the beamforming unit. Based on the beam control word, it further forms the receiving control parameters required by the RF receiving unit, which are then packaged by the beamforming unit and sent to the RF receiving unit via optical fiber.

[0044] The radio frequency receiving unit performs frequency conversion, filtering, amplification, and digitization on each input radio frequency signal according to the receiving control parameters, and then packages them and sends them to the beamforming unit through optical fiber.

[0045] The beamforming unit multiplies the IQ data of the radio frequency receiving unit according to the beam weighting coefficient to obtain the synthesized dual-polarized digital beam sent to the telemetry baseband subsystem.

[0046] This invention calculates the antenna gain of the target and interference in real time online based on the measured unit-level phased array antenna radiation pattern, achieving precise control of the signal amplitude of the target and interference. Compared with traditional modeling and simulation methods, it fully considers the special characteristics of airborne antennas and achieves higher fidelity. This invention adopts a universal RF analog input interface, interfacing with mature electromagnetic propagation simulation systems and electromagnetic environment construction systems, offering good versatility. This invention employs a method of digitizing RF analog signal units and using back-end digital multi-beamforming, allowing for flexible combinations of different target and interference numbers by adjusting the digital weighting system in real time.

[0047] Furthermore, the reading and transmission of the unit-level radiation pattern is performed by dividing the antennas of the entire array into different categories, including:

[0048] In a microwave anechoic chamber, the receiving beam pattern of the antenna is tested to obtain the radiation pattern of each element. Based on the difference in radiation pattern, they are divided into appropriate categories. For example, an airborne antenna with 2000 elements can typically be divided into 50 categories. Antenna elements with similar positions on the array surface often exhibit similar coupled radiation characteristics.

[0049] The beam scheduling module reads all frequency points and all categories of radiation pattern data based on all frequencies involved in the simulation;

[0050] The radiation pattern calculation unit receives the radiation patterns of all types of units and stores them in the DDR, so as to quickly look up the unit gain of the corresponding azimuth and elevation beams.

[0051] Furthermore, the antenna simulation system is part of a larger airborne telemetry simulation system, which also includes:

[0052] The telemetry baseband system is responsible for demodulation, decoding, and frame de-framing of the telemetry digital beam, target angle measurement and tracking, and generation of telemetry analog coded signals.

[0053] The electromagnetic propagation simulation system is responsible for simulating multipath propagation and fading of the telemetry simulation encoded signal given by the telemetry baseband system, and outputting the modulated composite signal (when the angle difference between the multipath signal and the target is small) or the target's main channel and multipath signal (when the angle difference is large) to the antenna simulation system described in this invention.

[0054] The electromagnetic environment simulation system is responsible for generating electromagnetic signals such as meteorological and interference signals based on the scenarios issued by the command and control.

[0055] The scenario generation and control system is responsible for constructing and distributing simulation scenarios, real-time intervention and control of scenarios, and data access from other systems to complete the comprehensive display of the situation.

[0056] Furthermore, the parameters received by the antenna simulation system from the telemetry baseband system via network or serial port are mainly the beam pointing of the test object. The beam pointing is obtained by the telemetry baseband system through sum and difference angle tracking calculation, and the sum and difference beams required for angle measurement are simulated and generated by the antenna simulation system.

[0057] Furthermore, the method by which the beam scheduling unit generates the beam control word includes:

[0058] After receiving the beam pointing of the telemetry baseband system, update it in the next frame beam control word. The frame time is 20ms or 50ms.

[0059] Upon receiving the multipath / interference pointer sent by the guidance unit in the scene generation and guidance system, update it in the beam control word of the next frame; the multipath / interference pointer is updated in real time.

[0060] The number of targets, the number of interferences, the target operating frequency, the interference frequency, and the target operating bandwidth sent by the guidance unit in the scenario generation and guidance system are sent once as initialization parameters during the simulation initialization phase. Among them, a certain interference frequency must be the same as a certain target operating frequency.

[0061] Furthermore, the radiation pattern calculation unit calculates the target signal gain weighting based on the real-time beam control pointing direction transmitted by the telemetry baseband and the real-time target angle transmitted by the tuning unit, thereby achieving amplitude control of the target signal; and calculates the gain weighting of the multipath / interference signal in real time according to the beam control pointing direction and the angle of the multipath / interference transmitted by the tuning unit. Specific calculation formulas include:

[0062] Horizontal polarization beam weighting coefficients:

[0063]

[0064] Vertical polarization beam weighting coefficients:

[0065]

[0066] In the formula: N is the number of horizontally polarized / vertically polarized elements in the antenna array, n = 1, ..., D is the target / multipath signal / interference designation, and m = 1, 2, 3 represent the sum, difference, and difference beams. The gain of the horizontal and vertical unit oscillators is obtained by querying the DDR for the radiation pattern calculation unit. For beam weighting, both values ​​are set to 1 for sum beams, and half of the array is set to 1 and the other half to -1 for difference beams, satisfying the sum and difference angle measurement requirements; d k,x d represents the azimuth distance of the k-th unit from the center of the array; k,y The elevation distance of the k-th unit from the center of the array; The beam control pointing azimuth and elevation angle transmitted by the telemetry baseband; ρ represents the true azimuth and elevation angle of the nth target / multipath signal / interference transmitted by the guidance unit; ρ is the polarization angle between the horizontal antenna element and the target's projection onto the antenna array plane. It should be noted that the telemetry horizontal and vertical polarized antenna elements appear in pairs with fixed relative positions.

[0067] Furthermore, the radiation pattern calculation unit sends the calculated beam weighting coefficients to the beamforming unit, whereby the horizontal and vertical polarizations are combined and calculated using the following formula:

[0068]

[0069]

[0070] In the formula: s n (t i ) is the radio frequency receiving unit at t i The IQ signal after digitization of the nth target / multipath signal / interference at any given time.

[0071] Furthermore, this invention also proposes an airborne phased array telemetry antenna simulation device, the device comprising:

[0072] The beam scheduling unit, using a general-purpose x86 architecture computer board, is responsible for parsing information such as target position, interference direction, and multipath direction sent by the beam direction adjustment unit, as well as beam pointing control parameters sent by the telemetry baseband system. It ultimately forms beam control words and sends them to the pattern calculation unit and beamforming unit. In addition, it provides large-capacity storage to save various system data, including unit-level pattern data.

[0073] The radiation pattern calculation unit uses a PowerPC computer board with fast calculation speed and strong real-time response. It is responsible for calculating the amplitude weighting coefficients of all targets, interference and multipath signals in multiple beams. It communicates with the beamforming unit through a high-speed serial RapidIO interface.

[0074] The beamforming unit employs a high-performance, real-time computing FPGA chip. Firstly, after receiving the receive control word generated by the beam control word parsed by the pattern calculation unit, it packages and transmits the data via optical fiber to the RF receiving unit according to the generation sequence. Secondly, after receiving the IQ digital signal packet from the RF receiving unit, it first splits it into IQ signals for each channel, and then performs a complex multiplication operation on the IQ signals for each channel according to the amplitude weighting coefficients sent by the pattern calculation unit, forming a horizontal polarization, vertical polarization sum, azimuth difference, and elevation difference beam that is sent to the telemetry baseband subsystem.

[0075] The radio frequency (RF) receiving unit comprises 16 RF analog channels and 1 digital receiving board. The RF analog channels perform low-noise amplification, down-conversion, and intermediate frequency (IF) filtering on the input RF signal. The digital receiving board performs digital sampling and filtering on the IF signal output from the RF analog channels to form unit-level IQ signals. Finally, the multi-channel IQ signals are packaged and sent to the beamforming unit via optical fiber.

[0076] Furthermore, the beam scheduling unit, radiation pattern calculation unit, and beamforming unit are all integrated into a single sub-unit using 6U standard plug-ins, referred to as the integrated processing sub-unit. Different plug-ins communicate with each other via the sub-unit backplane, SRIO switching board, and network switching board. The radio frequency receiving unit forms a separate sub-unit. The radio frequency receiving unit and the integrated processing sub-unit communicate via optical fiber, transmitting the receive control word and unit-level digital IQ signals.

[0077] like Figure 3 As shown, the first embodiment of the present invention proposes a real-time signal-level echo simulation method for airborne phased array radar, the method comprising the following steps:

[0078] S10: After receiving the initialization information, including the number of targets, operating frequency, number of interferences, operating frequency, number of multipaths, operating frequency, and the channel ID number of the corresponding radio frequency receiving unit, the beam scheduling computer searches for and loads the radiation patterns of all classification units at the corresponding frequencies into its DDR memory. It then extracts the gain values ​​of all signals involved in the initialization scenario, such as targets, interferences, and multipaths, at the corresponding azimuth and elevation angles and sends them to the radiation pattern computer via the network.

[0079] It should be noted that the system will group targets, multipath, and interference according to frequency, with the same frequency grouped together. The total number of all signals should not exceed 16. Interference and multipath are not necessarily required and can be flexibly configured. The gain value is extracted in the beam scheduling computer, and the pattern gain value corresponding to the azimuth and elevation angles of all signals relative to the antenna array is updated in real time for each frame. The measured element-level phased array antenna pattern is obtained by actual measurement in a microwave anechoic chamber or by offline fine simulation using professional software.

[0080] S20. After receiving the initialization beam control word converted from the initialization information by the beam scheduling computer, the pattern computer groups the signals according to the operating frequency and configures the group weights.

[0081] It should be noted that one target corresponds to one group, and one group corresponds to six digital beams ultimately generated to the telemetry baseband, namely, the horizontal and vertical polarized sum beam, the azimuth difference beam, and the elevation difference beam. The simulation system of this invention supports a maximum of four targets, i.e., four groups.

[0082] S30. After initialization and configuration are complete, the beam scheduling computer returns an initialization completion message to the training director, who can then begin subsequent simulations. The beam scheduling computer receives real-time updates from the training director regarding the target, interference, multipath angles, and aircraft attitude information. It transforms these information into the antenna array coordinate system and, combined with the beam pointing transmitted from the telemetry baseband, generates a beam control word, which is then sent to the pattern computer. Simultaneously, it transmits the corresponding azimuth and elevation angles in the array coordinate system for each signal (RF channel).

[0083] It should be noted that the beam pointing transmitted by the telemetry baseband is defined in the array coordinate system, while the position, velocity, and angle information of the target, interference, multipath, and carrier aircraft are defined in the geocentric coordinate system. All coordinate transformations involved in this invention are completed within the beam scheduling computer.

[0084] S40. The radiation pattern computer calculates the weighting coefficients of each signal based on the signal angles within each group, according to equations (1) and (2), and transmits them to the beamforming unit via SRIO.

[0085] It should be noted that the calculation process for the weighting coefficients of each signal is exactly the same when the radiation pattern computer calculates them. The difference lies in the angle between the actual angle of each signal and the beam pointing angle, which results in different coefficients.

[0086] S50. The beamforming unit, based on the grouping weights and weighting coefficients (corresponding to the weighting coefficients of each radio frequency channel), first multiplies the channels and then generates 24 beams (maximum) corresponding to 4 targets according to equations (3) and (4). The IQ data of the 24 beams are packaged and sent to the telemetry baseband through 4 optical fibers (each optical fiber corresponds to 6 beams of 1 target, and the data rate in this invention is 6.4Gbps).

[0087] It should be noted that the number of targets and beams can be expanded by simply increasing the number of RF receiving units, the number of RF receiving units' channels, and the number of beamforming units. The architecture of this invention has scalability and versatility in terms of quantity, because each target is relatively independent.

[0088] During the simulation, when the operating frequency changes, the beam control needs to be switched to standby or paused, and the initialization information needs to be resent before the simulation training can continue. If the number or specific ratio of signals in each group changes, there is no need to pause and the simulation can continue directly. This is because the beam scheduling computer needs seconds to load a large amount of unit-level pattern data, while other changes are included in the beam control word in real time.

[0089] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0090] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0091] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0092] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0093] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A simulation method for an airborne phased array telemetry antenna, characterized in that... The simulation system includes a directing unit, a beam scheduling unit, a pattern calculation unit, an RF receiving unit, and a beamforming unit. The simulation steps are as follows: Step 1: The directing unit sends basic operating parameters to the beam scheduling unit via the network. The beam scheduling unit sends the basic operating parameters to the pattern calculation unit in sequence. At the same time, it reads the pre-stored unit-level measured antenna pattern data for the operating frequency and sends it to the pattern calculation unit. The basic operating parameters include the position of each target, the direction of each interference, and the direction of each multipath signal in the body coordinate system, and generate a beam control word that includes the direction of each beam, operating frequency, operating bandwidth, interference intensity, and direction in the array coordinate system. The acquisition of the unit-level measured antenna pattern data is as follows: the antenna is tested for receiving beamwidth in a microwave anechoic chamber, the pattern data of each unit is acquired, and then the antenna pattern data is divided into a certain number of categories according to the similarity of the pattern data of each antenna unit. The pattern data of each type of antenna unit is stored in the hard disk of the beam scheduling unit. Step 2: The pattern calculation unit calculates the gain of targets and interference in each beam in real time online, and sends the weighting coefficients of each beam to the beamforming unit. Horizontal polarization beam weighting coefficients: Vertical polarization beam weighting coefficients: In the formula: N This represents the number of horizontally polarized / vertically polarized elements in the antenna array. n= 1, … , D The target / multipath signal / interference is labeled, and m=1, 2, 3 represent the sum, difference, and difference beams. , The gain of the horizontal and vertical cell oscillators for all classes of cell patterns stored in DDR; For beam weighting, both values ​​are set to 1 for sum beams, and half of the array is set to 1 and the other half to -1 for difference beams, thus satisfying the sum and difference angle measurement requirements. For the first k The azimuth distance of each unit from the center of the array; For the first k The elevation distance of each unit from the center of the array; The waveguide pointing azimuth and elevation angle in the array coordinate system for telemetry baseband transmission; The array coordinate system sent to the guidance unit n True azimuth and elevation angle of individual targets / multipath signals / interference; The polarization angle between the horizontal antenna element and the target projected onto the antenna array plane; Step 3: The beamforming unit calculates the simulated horizontal and vertical polarization composite signal based on the beam weighting coefficients. In the formula: For the radio frequency receiving unit in Time for the first n The IQ signal is obtained by digitizing the target / multipath signal / interference.

2. The airborne phased array telemetry antenna simulation method according to claim 1, characterized in that: The beam scheduling module reads complete radiation pattern data for all frequencies and categories involved in the simulation and loads it into its DDR at once. Before each beam control word is sent, it selects the unit gain values ​​for all categories, corresponding frequencies, and corresponding target / interference / multipath signal azimuth and elevation angles from the radiation pattern data and sends them to the radiation pattern calculation unit.

3. The airborne phased array telemetry antenna simulation method according to claim 1, characterized in that: The radiation pattern calculation unit, according to the radiation pattern category distribution matrix, restores the gain values ​​of all received class units to the gain values ​​of all units on the entire array, thereby calculating the overall array composite gain.

4. The airborne phased array telemetry antenna simulation method according to claim 1, characterized in that: The radio frequency receiving unit includes 16 configurable channels and can output 16 IQ signals to the back-end beamforming unit. By configuring and adjusting different digital weighting coefficients through the beamforming unit, different ratios of the number of target, multipath, and interference signals can be obtained, thereby simulating task scenarios with different numbers of single / multi-target, single / multi-interference, and multipath signals.

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