Calibration system and calibration method based on active radar cross section
Through the active radar scattering cross-section calibration system based on the DRFM system, the UAV mounting platform and RCS simulator are used to solve the problems of unstable accuracy, strong environmental dependence and complex operation of the traditional RCS calibration method, and efficient and accurate RCS calibration is achieved.
Patent Information
- Application Number
- CN202510534668.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-27
- Publication Date
- 2025-08-08
AI Technical Summary
The traditional RCS calibration method relies on passive calibration bodies, is complex in production and high in cost, the scattering characteristics are easily affected by environmental factors, and the test environment is strict, making it difficult to apply in complex electromagnetic environments or space-constrained scenarios. The operation process is cumbersome and inefficient.
The active radar scattering cross-section calibration system based on the DRFM system is adopted, and the UAV mounting platform and RCS simulator are used, including the aerial RCS simulator host, speaker transceiver antenna and gimbal. Through the DRFM simulation channel, radio frequency unit and command transceiver and control unit, precise control of transmission and reception signals is achieved, environmental errors are reduced, and operational processes are simplified.
It improves the accuracy and efficiency of RCS calibration, broadens the application range, and can calibrate under complex electromagnetic environments and space-constrained conditions, reduces operational difficulty and manual measurement complexity, and is versatile and versatile.
Smart Images
Figure CN120446885A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of radar target characteristic measurement, and in particular to a calibration system and a calibration method based on active radar cross section. Background Art
[0002] As is well known, Radar Cross Section (RCS) is an important indicator for measuring the intensity of the scattered signal of a target under radar wave illumination. RCS has key applications in many fields such as radar target recognition, stealth technology research, and remote sensing detection. Accurately obtaining the RCS value of a target is crucial for evaluating the target's detectability, optimizing radar system performance, and conducting research in related fields.
[0003] Traditional RCS calibration methods mainly rely on passive calibration objects such as metal balls, angular reflectors, and flat plates. However, these methods have many limitations: 1. Strict requirements for calibration objects: Passive calibration objects must have stable and known scattering characteristics, and the manufacturing process is complex and costly. At the same time, their scattering characteristics are easily affected by environmental factors such as temperature, humidity, and surface conditions, resulting in unstable calibration accuracy; 2. The test environment is highly restricted: The test site must be open and have low background clutter to reduce the impact of external interference on the measurement results; this makes it difficult to meet test conditions in practical applications, especially in complex electromagnetic environments or scenarios with limited space; 3. The operation process is cumbersome: When using passive calibration objects for calibration, it is necessary to accurately measure parameters such as the distance and angle between the calibration object and the radar, and perform multiple measurements and data processing, which is complicated and inefficient.
[0004] With the development of modern radar technology, higher requirements are placed on the accuracy, efficiency and adaptability of RCS calibration. Therefore, the development of an active multifunctional RCS calibration system and calibration method that can solve the above problems has important practical significance and application value. Summary of the Invention
[0005] In order to overcome the deficiencies in the background technology, the present invention discloses a calibration system and a calibration method based on active radar cross section.
[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions: A calibration system based on active radar cross section includes an unmanned aerial vehicle (UAV) mounting platform and an RCS simulator. The RCS simulator simulates radar target echo signals based on the DRFM system. The system includes an airborne RCS simulator host, a horn transceiver antenna, and a gimbal. The horn transceiver antenna is used to receive and radiate radio frequency signals. The gimbal is used to mount a receiving horn antenna or a target simulator on the UAV mounting platform. The airborne RCS simulator host includes a chassis and the DRFM simulation channel, radio frequency unit, command transceiver and control unit, and power module installed inside the chassis; The DRFM analog channel is used to collect radar signals and modulate target echo information to obtain low-intermediate-frequency target echo signals; The RF unit includes an RF transmit channel, an RF receive channel, a frequency synthesizer, and a circulator. The RF transmit channel is used to up-convert and power-amplify low-intermediate-frequency target echo signals. The RF receive channel is used to power-adjust and down-convert received radar signals. The frequency synthesizer is used to provide the local oscillator required for RF up- and down-conversion and the clock signal required for baseband operation. The circulator is used for transceiver conversion between the RF transmit channel, the RF receive channel, and the horn antenna. The command receiving and sending and control unit is used to receive the control commands and parameter information sent by the UAV mounting platform, and after processing and conversion, obtain the control signals of each unit of the echo simulation equipment, control the operation of each unit, and also transmit the working status information of the simulation equipment to the ground for display.
[0007] The active radar cross-section-based calibration system includes a UAV mounting platform comprising a multi-rotor UAV, a UAV battery and charging module, and a UAV ground control station.
[0008] In the active radar cross-section-based calibration system, the chassis adopts an integrated chassis structure, and the power module converts the received 28V power supply to obtain the power signal required for the operation of the internal units.
[0009] A calibration method for a calibration system based on an active radar cross section comprises the following steps: S1. Before calibration, the parameters required for calibration and the flight route of the UAV are set on the ground, the UAV mounting platform is checked, and the speaker transceiver antenna is installed on the UAV using the gimbal; S2. Check the working status of the ground test radar and the status of the UAV ground control station, and start the test on the ground. The UAV will take off and fly tangentially and radially according to the predetermined route and speed; S3, controlling the RCS simulator to start working according to the working parameters set in the control software of the external laptop computer; S4. The ground radar searches for and tracks the simulated target in the direction of the UAV and records the tracking data. The specific steps are as follows: after the horn transceiver antenna receives the radar RF signal, the signal enters the RF receiving channel through a circulator, undergoes power adjustment and down-conversion processing on the signal to obtain a low-intermediate frequency signal that can be directly collected by a high-speed broadband AD. The signal is then modulated into an echo signal. Finally, the modulated signal is subjected to high-speed broadband DA conversion. After up-conversion and power amplification adjustment, the final RF echo signal is obtained. The RF echo signal is radiated through the circulator and the horn transceiver antenna through the RF transmission channel and then received by the radar. The radar operator records the effective tracking data. S5. The drone changes its flight angle and speed, measures the simulator RCS again, and records the relevant data. S6. The drone returns home, turns off the radar and active equipment, the test ends, and the tracking data is collated.
[0010] In the calibration method for the active radar cross-section calibration system, the parameters required for calibration are bound in step S1, specifically the RCS values of commonly used targets, including those of angular reflection, flat panel, civil aviation, TW328 UAV, Y-5, Mi-17 helicopters, and missile targets. These values are obtained by simulation calculation and darkroom testing to obtain k values, and the RCS values of these targets are bound. The horn transceiver antenna covers the receiving antennas of the radar L / S / C / X / KU bands, and the calibration work of multiple radars is carried out simultaneously.
[0011] In the calibration method of the active radar cross section calibration system, the gimbal in step S1 is a dual-axis gimbal turntable, which adopts a rotatable connection platform made of carbon fiber. The dual-axis gimbal turntable can suspend the RCS passive calibration body, active equipment and battery equipment.
[0012] In the calibration method of the active radar cross section-based calibration system, the echo signal modulation in step 3 includes high-speed acquisition, storage, amplitude modulation, digital signal delay, and Doppler frequency modulation processing.
[0013] In the calibration method of the active radar cross section calibration system, the data collation described in step S6 is to compare the target RCS value measured by the radar with the RCS value emitted by the RCS simulator, and correct the radar RCS by measuring the RCS values at different angles and different speeds.
[0014] Due to the adoption of the above technical solution, the present invention has the following beneficial effects: The calibration method of the active radar cross section calibration system described in the present invention uses an RCS simulator to simulate radar target echo signals based on a DRFM system. The simulated echo can realistically reflect the amplitude, delay, and Doppler frequency characteristics of the airborne target echo, accurately control the transmitted and received signals, and reduce the influence of environmental factors and equipment errors on the calibration results. Compared with traditional passive calibration methods, the accuracy of RCS calibration is significantly improved, and there is no need to rely on specific test sites and complex calibration objects. RCS calibration can be performed in various complex electromagnetic environments and spatial conditions, thereby broadening the scope of application. The present invention simplifies the operating process, reduces manual measurement and complex data processing steps, improves calibration efficiency, and reduces operational difficulty. Signal transmission and modulation modes can be flexibly adjusted according to different test requirements to achieve RCS calibration for different types of radar systems and multiple targets, and has strong versatility and multifunctionality. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is a system block diagram of the present invention.
[0016] Figure 2 It is a working principle diagram of the present invention. DETAILED DESCRIPTION
[0017] The present invention can be explained in detail by the following examples, the purpose of which is to disclose the present invention and to protect all technical improvements within the scope of the present invention.
[0018] Combined with attachment Figure 1-2The active radar cross section calibration system includes a UAV mounting platform and an RCS simulator. The UAV mounting platform includes a multi-rotor UAV, a UAV battery and charging module, and a UAV ground control station. The RCS simulator simulates radar target echo signals based on the DRFM system, and includes an aerial RCS simulator host, a horn transceiver antenna, and a pan / tilt. The horn transceiver antenna is used to receive and radiate radio frequency signals, and the pan / tilt is used to install a receiving horn antenna or a target simulator on the UAV mounting platform. The aerial RCS simulator host includes a chassis and a DRFM simulation channel, a radio frequency unit, a command transceiver and control unit, and a power module arranged inside the chassis. The chassis adopts an integrated Chassis structure, the power module converts the received 28V power supply to obtain the power signal required for the internal unit operation; the DRFM analog channel is used to collect radar signals and modulate the target echo information to obtain a low-intermediate-frequency target echo signal; the RF unit includes an RF transmit channel, an RF receive channel, a frequency synthesizer and a circulator. The RF transmit channel is used to up-convert and power-amplify the low-intermediate-frequency target echo signal, the RF receive channel is used to power-adjust and down-convert the received radar signal, the frequency synthesizer is used to provide the local oscillator required for RF up- and down-conversion and the clock signal required for baseband operation, and the circulator is used for transceiver conversion between the RF transmit channel, the RF receive channel and the horn antenna; The command receiving and sending and control unit is used to receive the control commands and parameter information sent by the UAV ground control station, and after processing and conversion, obtain the control signals of each unit of the echo simulation equipment, control the operation of each unit, and at the same time transmit the working status information of the simulation equipment to the ground for display.
[0019] A calibration method for a calibration system based on an active radar cross section comprises the following steps: S1. Before calibration, the parameters required for calibration and the flight route of the UAV are set on the ground, the UAV mounting platform is checked, and the speaker transceiver antenna is installed on the UAV using the gimbal; S2. Check the working status of the ground test radar and the status of the UAV ground control station, and start the test on the ground. The UAV will take off and fly tangentially and radially according to the predetermined route and speed; S3, controlling the RCS simulator to start working according to the working parameters set in the control software of the external laptop computer; S4. The ground radar searches for and tracks the simulated target in the direction of the UAV and records the tracking data. The specific steps are as follows: after the horn transceiver antenna receives the radar RF signal, the signal enters the RF receiving channel through a circulator, undergoes power adjustment and down-conversion processing on the signal to obtain a low-intermediate frequency signal that can be directly collected by a high-speed broadband AD. The signal is then modulated into an echo signal. Finally, the modulated signal is subjected to high-speed broadband DA conversion. After up-conversion and power amplification adjustment, the final RF echo signal is obtained. The RF echo signal is radiated through the circulator and the horn transceiver antenna through the RF transmission channel and then received by the radar. The radar operator records the effective tracking data. S5. The drone changes its flight angle and speed, measures the simulator RCS again, and records the relevant data. S6. The UAV returns home, turns off the radar and active equipment, and ends the test. The tracking data is collated and the target RCS value measured by the radar is compared with the RCS value emitted by the RCS simulator. The radar RCS is calibrated by measuring the RCS values at different angles and speeds.
[0020] Furthermore, in step S1, the parameters required for calibration are bound, and the RCS values of commonly used targets are bound, including the RCS values of angular reflection, flat panel, civil aviation, TW328 UAV, Yun-5, Mi-17 helicopters and missile targets. These values are obtained by simulation calculation and darkroom testing to obtain k values, and the RCS values of these targets are bound; the horn transceiver antenna covers the receiving antenna of the radar L / S / C / X / KU bands, and the calibration work of multiple radars is carried out simultaneously.
[0021] Furthermore, the gimbal in step S1 is a dual-axis gimbal, which uses a rotatable connection platform made of carbon fiber. The dual-axis gimbal can suspend RCS passive calibration bodies, active equipment, and battery equipment. Example 1:
[0022] RCS calibration of an aircraft model in a dark room: In a microwave anechoic chamber, the aircraft model is placed on the dual-axis cloud turntable of a multi-rotor drone, and the active RCS simulator is placed in a suitable position to ensure that the radar signal can effectively illuminate both. Parameter settings: Set the radar operating frequency to 10 GHz, the transmit power to 100 W, the pulse width to 1 μs, and the repetition frequency to 1000 Hz; set the RCS simulator to linear FM signal modulation mode with a gain of 20 dB; Calibration: Start the radar and RCS simulator. After the horn transceiver antenna receives the radar RF signal, it enters the RF receiving channel through a circulator for power adjustment and down-conversion processing to obtain a low-IF signal that can be directly collected by a high-speed broadband AD. This signal is then modulated as an echo signal. Finally, the modulated signal is converted into a high-speed broadband DA. Through up-conversion and power amplification adjustment, the final RF echo signal is obtained. The RF echo signal is radiated through the circulator and the horn transceiver antenna through the RF transmission channel and then received by the radar. The experimenter records the effective data and compares the target RCS value measured by the radar with the theoretical value of the RCS simulator. The error is within ±3dBsm, meeting the measurement accuracy requirements. Example 2:
[0023] Radar RCS calibration in complex field environments Fix the RCS simulator and the speaker transceiver antenna on the dual-axis cloud turntable of the multi-rotor drone. To reduce the influence of ground clutter, the drone should be taken off in an open area as much as possible. When choosing a flight route, make sure there are no tall buildings around. Parameter adjustment: Considering the interference of the outdoor environment, the radar transmission power is appropriately reduced to 50W, the bandwidth is selected to 10M, the operating frequency is 5G, and the waveform is selected as the phase coding tracking waveform to enhance the anti-interference capability.
[0024] Start measurement: The drone takes off and enters the predetermined location according to the predetermined route and altitude. The RCS simulator is activated to detect and receive radar signals. The radar is turned on and aimed at the simulated target in the air to search for the target. After the simulator receives the radar signal, it enters the RF receiving channel through a circulator, adjusts the power of the signal and performs down-conversion processing to obtain a low-IF signal that can be directly collected by a high-speed broadband AD. This signal is then modulated into an echo signal and finally subjected to a high-speed broadband DA conversion. After up-conversion and power amplification, the final RF echo signal is obtained. The ground laptop computer calls the simulated RCS signal through the database and forwards the signal. After the radar detects the simulated RCS target signal, it tracks the target. The experimenter records the effective radar tracking data and compares the target RCS value measured by the radar with the theoretical value of the RCS simulator. After a test is completed, the drone changes its flight posture and records the RCS data measured by the radar at different flight speeds and angles. After multiple measurements and data optimization, as well as comparison with the simulator's RCS data, the radar's effective cross-sectional area RCS is finally calibrated. Compared with the measurement results in a laboratory environment, this method has an error within ±3dBsm.
[0025] The parts not described in detail in this invention are prior art.
[0026] The embodiments selected herein for the purpose of disclosing the invention are presently considered suitable, but it should be understood that the invention is intended to include all variations and modifications of the embodiments that fall within the scope of the concept and invention.
Claims
1. A calibration system based on active radar cross section, including a UAV mounting platform and an RCS simulator, characterized by: The RCS simulator simulates radar target echo signals based on the DRFM system. It includes an airborne RCS simulator host, a horn transceiver antenna, and a gimbal. The horn transceiver antenna is used to receive and radiate radio frequency signals, and the gimbal is used to install a receiving horn antenna or target simulator on the UAV mounting platform. The airborne RCS simulator host includes a chassis and the DRFM simulation channel, radio frequency unit, command transceiver and control unit, and power module installed inside the chassis; The DRFM analog channel is used to collect radar signals and modulate target echo information to obtain low-intermediate-frequency target echo signals; The RF unit includes an RF transmit channel, an RF receive channel, a frequency synthesizer, and a circulator. The RF transmit channel is used to up-convert and power-amplify low-intermediate-frequency target echo signals. The RF receive channel is used to power-adjust and down-convert received radar signals. The frequency synthesizer is used to provide the local oscillator required for RF up- and down-conversion and the clock signal required for baseband operation. The circulator is used for transceiver conversion between the RF transmit channel, the RF receive channel, and the horn antenna. The command receiving and sending and control unit is used to receive the control commands and parameter information sent by the UAV mounting platform, and after processing and conversion, obtain the control signals of each unit of the echo simulation equipment, control the operation of each unit, and also transmit the working status information of the simulation equipment to the ground for display.
2. The active radar cross section calibration system according to claim 1, wherein: The drone mounting platform includes a multi-rotor drone, drone battery and charging module, and a drone ground control station.
3. The active radar cross section calibration system according to claim 1, wherein: The chassis adopts an integrated chassis structure, and the power module converts the received 28V power supply to obtain the power signal required for the internal unit to work.
4. The calibration method of the active radar cross section calibration system according to any one of claims 1 to 3, characterized in that: The specific steps include: S1. Before calibration, the parameters required for calibration and the flight route of the UAV are set on the ground, the UAV mounting platform is checked, and the speaker transceiver antenna is installed on the UAV using the gimbal; S2. Check the working status of the ground test radar and the status of the UAV ground control station, and start the test on the ground. The UAV will take off and fly tangentially and radially according to the predetermined route and speed; S3, controlling the RCS simulator to start working according to the working parameters set in the control software of the external laptop computer; S4. The ground radar searches for and tracks the simulated target in the direction of the UAV and records the tracking data. The specific steps are as follows: after the horn transceiver antenna receives the radar RF signal, it enters the RF receiving channel through a circulator to adjust the power and down-convert the signal to obtain a low-intermediate frequency signal that can be directly collected by a high-speed broadband AD. The signal is then modulated into an echo signal. Finally, the modulated signal is converted into a high-speed broadband DA. After up-conversion and power amplification, the final RF echo signal is obtained. The RF echo signal is radiated through the circulator and the horn transceiver antenna through the RF transmission channel and then received by the radar. The radar operator will track and record the effective data. S5. The drone changes its flight angle and speed, measures the simulator RCS again, and records the relevant data. S6. The drone returns home, turns off the radar and active equipment, the test ends, and the tracking data is collated.
5. The calibration method of the active radar cross section calibration system according to claim 4, characterized in that: In step S1, the parameters required for calibration are bound, specifically the RCS values of commonly used targets, including those for angular reflection, flat panel, civil aviation, TW328 UAV, Yun-5, Mi-17 helicopters, and missile targets. These values are obtained by simulation calculation and darkroom testing to obtain k values, and the RCS values of these targets are bound. The horn transceiver antenna covers the receiving antenna of the radar L / S / C / X / KU bands, and the calibration work of multiple radars is carried out simultaneously.
6. The calibration method of the active radar cross section calibration system according to claim 4, wherein: The gimbal in step S1 is a dual-axis gimbal that uses a rotatable carbon fiber connection platform. The dual-axis gimbal can suspend RCS passive calibration bodies, active equipment, and battery equipment.
7. The calibration method of the active radar cross section calibration system according to claim 4, wherein: The echo signal modulation in step 3 includes high-speed acquisition, storage, amplitude modulation, digital signal delay and Doppler frequency modulation processing.
8. The calibration method of the active radar cross section calibration system according to claim 4, characterized in that: The data sorting described in step S6 is to compare the target RCS value measured by the radar with the RCS value emitted by the RCS simulator, and to calibrate the RCS of the radar by measuring the RCS values at different angles and speeds.