Circular array radar antenna assembly self-inspection and amplitude-phase self-calibration system

Abstract

The invention discloses an on-line self-checking and amplitude-phase self-calibration system for a circular array radar antenna assembly, which combines the structural characteristics of a circular array radar, and is characterized in that external calibration antennas are mounted around a base of an equipment base cage, a special calibration branch is designed for a bottom power division network, and a special calibration channel is designed for a frequency synthesizer; a self-checking and self-calibrating time slice is inserted into a radar real-time signal processing time sequence, self-checking can be carried out on a TR assembly at the front end of a phased array radar antenna in real time, and meanwhile, monitoring and self-calibrating are carried out on the amplitude and the phase of the assembly. The invention provides a self-checking and self-calibration system capable of reducing complexity, which only needs to calibrate and record basic data once when leaving a factory, insert a self-checking and self-calibration time slice and perform real-time on-line self-checking on an antenna assembly in the subsequent operation process of a normal search tracking mode of a radar system, and finish amplitude-phase on-line self-checking and self-calibration through comparison with the basic data.

Description

Technical Field

[0001] The invention relates to the technical field of phased array radars, and in particular to a circular array radar antenna component self-checking and amplitude-phase self-calibration system. Background Art

[0002] Phased array radar is a radar system based on microwave phased array technology. It consists of a large number of transmitting and receiving units and is widely used in aerospace, national defense, military and civilian fields. In modern high-performance phased array radar systems, due to the high complexity of the phased array radar system, wide operating frequency, and numerous antenna units, its component failure rate is relatively high. Therefore, in order to ensure the reliability and stability of the phased array radar system, regular self-inspection and maintenance are required. As an important non-destructive testing method, phased array radar component self-inspection technology can perform comprehensive self-inspection on each component, detect potential faults in a timely manner, and take corresponding maintenance measures to ensure the normal operation of the radar system, reducing maintenance costs and improving maintenance efficiency.

[0003] Traditional radar phased array component self-test technology focuses on using existing test equipment, signal sources or self-built sites for testing and analysis, especially focusing on the measurement and comparison of various component parameters. However, these methods usually take a lot of time and resources, and in some cases may not fully cover all potential fault conditions. Therefore, with the development of radar technology and the improvement of automation, new radar phased array built-in component self-test and self-calibration systems are particularly important. Summary of the invention

[0004] The purpose of the invention is to disclose an online self-checking and amplitude-phase self-calibration system for a circular array radar antenna assembly.

[0005] The technical solution to realize the present invention is: an online self-inspection and amplitude and phase self-calibration system for circular array radar antenna components, the radar whole machine integrates special self-inspection and self-calibration functions, external calibration antennas are installed around the base of the equipment cage, a special calibration channel is added to the power division network, a special calibration module is added to the frequency synthesizer, a calibration mode is added to the signal processing board, a self-inspection and self-calibration time slice is inserted in the timing, and the calibration signal is generated and received and processed using its own hardware conditions to complete the online self-inspection and amplitude and phase self-calibration of the circular array radar antenna components.

[0006] Furthermore, the external calibration antenna is composed of multiple waveguide antennas, which are evenly arranged around the bottom of the frustum array. Each external calibration antenna is responsible for calibrating the adjacent antenna stand array. The relative position relationship between the external calibration antenna and each front-end channel remains unchanged, and the amplitude-phase relationship is relatively fixed.

[0007] Furthermore, the power division network adds a dedicated calibration channel to connect the external calibration antenna to the frequency synthesizer to complete the transmission of the calibration radio frequency signal.

[0008] Furthermore, the frequency synthesizer is added with a dedicated calibration module for realizing signal amplification, filtering, up / down mixing, image frequency suppression and switching of the transmitting / receiving path.

[0009] Furthermore, the signal processing board is responsible for timing generation, enabling frequency synthesizer working mode switching, controlling ADC and DAC, and completing multi-channel intermediate frequency calibration signal generation and acquisition.

[0010] Furthermore, the calibration mode includes transmission calibration and reception calibration, and a self-check and self-calibration time slice is inserted in the timing sequence, and the self-check and amplitude and phase self-calibration of the transmission and reception channels of the antenna array TR component are completed by using its own hardware conditions.

[0011] The present invention also provides a self-calibration method based on the above circular array radar antenna assembly self-checking and amplitude and phase self-calibration system, comprising the following steps:

[0012] S1. During the self-check and self-calibration of the antenna stand array receiving channel, the signal processing board enables the frequency synthesizer to work in the receiving calibration working mode during the calibration time slice;

[0013] S2. The signal processing board enables the DA to generate a fixed amplitude and phase point frequency signal during the calibration time slice and outputs it to the frequency synthesizer;

[0014] S3. The frequency synthesizer up-converts the calibration intermediate frequency signal to an RF signal, outputs it through the calibration RF channel, transmits it in the calibration branch of the power division network, and finally radiates it to the antenna stand array through the calibration antenna;

[0015] S4. The antenna array receives the calibration RF signal, which passes through the receiving branch of the transceiver component, the power divider, the down-mixer, the intermediate frequency amplification and filtering branch in sequence, and finally becomes a calibration intermediate frequency signal, which is sent to the AD sampling port of the signal processing board;

[0016] S5. The AD sampling module of the signal processing board samples the calibration intermediate frequency signal, completes FFT signal processing inside the signal processing board, extracts the amplitude and phase characteristic information of the antenna array receiving channel, and stores it;

[0017] S6. During the self-check and self-calibration of the antenna stand array transmission channel, the signal processing board is in the calibration time slice, enabling the frequency synthesizer to work in the transmission calibration working mode;

[0018] S7. The signal processing board enables the DA to generate a fixed amplitude and phase point frequency signal during the calibration time slice and outputs it to the frequency synthesizer;

[0019] S8. The frequency synthesizer up-converts the calibration intermediate frequency signal to a radio frequency signal, outputs it through the excitation channel, passes through the power division network, and is sent to the excitation port of the antenna stand array;

[0020] S9. The antenna stand array opens the transmission channel in turn, radiates the calibration RF signal through the antenna, receives the calibration signal through the calibration branch of the power division network, and transmits it to the frequency synthesizer calibration interface;

[0021] S10. The frequency synthesizer mixes the calibration RF signal down to an intermediate frequency signal and sends it to the AD sampling port of the signal processing board;

[0022] S11. The signal processing board completes AD sampling and signal processing, calculates the amplitude and phase information of the antenna array transmission channel, and stores it;

[0023] S12. After completing the above operations, the amplitude and phase values ​​are compared by using the basic data obtained in the same way as in the microwave darkroom and pre-stored in the FLASH as a reference to calculate the difference in amplitude and phase; if the difference exceeds the threshold, the self-test channel is judged to be abnormal and the fault is reported; if the difference does not exceed the threshold, it is converted into the compensation code value of the antenna stand phase shifter and attenuator to complete the self-calibration of the antenna stand array receiving channel

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention only needs to be calibrated once and the basic data recorded before leaving the factory. Subsequently, during the normal search and tracking mode operation of the radar system, a self-check and self-calibration time slice is inserted to perform real-time online self-check of the antenna assembly, and complete the online self-check and self-calibration of amplitude and phase by comparing with the basic data. There is no need to build a dedicated site or equip external testing equipment, the structure is simple, the complexity of self-check and calibration is greatly reduced, a lot of time and resources are saved, maintenance costs are reduced, and maintenance efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a block diagram of the circular array radar self-test and amplitude and phase self-calibration system.

[0026] Figure 2 Schematic diagram of the circular array radar calibration antenna and antenna array structure. DETAILED DESCRIPTION

[0027] like Figure 1 As shown, an online self-inspection and amplitude and phase self-calibration system for circular array radar antenna components is provided. In combination with the structural characteristics of the circular array radar, an external calibration antenna is installed at the base of the equipment cage, a dedicated calibration channel is designed for the bottom power division network, and a dedicated calibration module is designed for the frequency synthesizer. Self-inspection and self-calibration time slices are inserted into the radar real-time signal processing timing, so that the TR component at the front end of the phased array radar antenna can be self-inspected in real time, and the amplitude and phase of the component can be monitored and self-calibrated at the same time.

[0028] After a traditional radar has been working for a long time, the amplitude and phase offsets caused by aging of components or replacement of damaged components must be recalibrated in a microwave darkroom, which requires corresponding signal sources, horn antennas, vector network analyzers and other supporting instruments. The test process and environment are extremely cumbersome and harsh. The present invention proposes a self-checking and self-calibration system with reduced complexity. It only needs to be calibrated once and the basic data is recorded before leaving the factory. Subsequently, during the normal search and tracking mode operation of the radar system, a self-checking and self-calibration time slice is inserted to perform real-time online self-check of the antenna components, and the amplitude and phase are completed by comparing with the basic data online.

[0029] The external calibration antenna is a waveguide antenna used to send and receive calibration radio frequency signals. It adopts a consistent vertical polarization method with the antenna array and is composed of multiple antennas evenly arranged around the bottom of the array. Each external calibration antenna is responsible for calibrating multiple adjacent antenna vertical panels. The relative position relationship between the detection antenna and each front-end channel remains unchanged, and each detection will not cause position error.

[0030] The power division network adopts a Wilkinson microstrip line power divider, including an excitation branch, a local oscillator branch, and a calibration branch. The calibration branch is connected to a plurality of calibration antennas, and the calibration antennas are interconnected with a frequency synthesizer.

[0031] The frequency synthesizer is a special custom design, which includes a local oscillator source, an excitation source, a mixer, an amplifier, an automatic gain controller, and a bandpass filter. In addition to providing an excitation local oscillator source, it also provides the reception, mixing, and amplification of calibration signals. When receiving, the RF signal is down-converted to an intermediate frequency and sent to the signal processing board for sampling; when transmitting, the calibration intermediate frequency signal is up-converted to a radio frequency and radiated to the antenna array through a power divider and a calibration antenna.

[0032] The signal processing board is responsible for controlling timing generation, signal generation and intermediate frequency acquisition. In the self-check and self-calibration time slice, it enables the frequency synthesizer to enter the self-calibration mode, generates a fixed amplitude and phase intermediate frequency signal to the frequency synthesizer, collects the self-calibration intermediate frequency signal output by the frequency synthesizer, performs FFT signal processing on it, and extracts the phase and amplitude characteristic information of the antenna array receiving and transmitting branches.

[0033] The present invention improves the structure of a traditional phased array radar, has a simple structure, adds an auxiliary calibration antenna and a calibration branch, uses its own hardware conditions to generate and receive a calibration signal for processing, has no requirements for an experimental environment and external equipment, reduces maintenance costs, and improves maintenance efficiency.

[0034] The present invention is described in detail below with reference to the embodiments.

[0035] Example

[0036] A circular array radar antenna assembly online self-test and amplitude and phase self-calibration system, such as Figure 1 , Figure 2 As shown in the figure, in combination with the structural characteristics of the circular array radar, six external calibration antennas are installed at the base of the equipment cage; in order to avoid coupling, the bottom power division network is designed with odd and even calibration branches, and the odd and even calibration branches are connected to the three calibration antennas respectively, and the calibration antenna is interconnected with the frequency synthesizer; the frequency synthesizer is designed with a dedicated odd and even calibration channel, and a self-check and self-calibration time slice is inserted in the radar real-time signal processing, which can perform self-check on the TR component at the front end of the phased array radar antenna in real time, and monitor and self-calibrate the amplitude and phase of the component at the same time.

[0037] The specific implementation steps are as follows:

[0038] S1. When the circular array radar is in normal working mode, the signal processing board is responsible for the timing generation of the whole machine, the generation and acquisition of echo signals, and the processing of echo signals; the signal processing board inserts a fixed time slice of 1ms at the end of the real-time signal processing timing for self-test and amplitude and phase self-calibration;

[0039] S2. When the antenna stand array receiving channel is self-checked and self-calibrated, the signal processing board enables the DA to generate a point frequency signal with a frequency of 200Mhz, an amplitude of 0dBm, a phase of 0°, and a time width of 20us during the calibration time slice, and outputs it to the intermediate frequency signal input interface socket of the frequency synthesizer through the amplifier, bandpass filter, and SMA socket;

[0040] S3. The signal processing board enables the frequency synthesizer to operate in the receive odd calibration mode;

[0041] S4. The frequency synthesizer up-converts the calibration intermediate frequency signal to a 5.2 GHz RF signal, passes through the calibration RF channel, first passes through the odd calibration output, is transmitted in the odd calibration branch of the power division network, and finally radiates from the odd calibration antenna to the antenna stand array;

[0042] S5. The antenna array receives 36 calibration RF signals, which are sequentially passed through the receiving branch of the transceiver component, the power divider, the down-mixer, and the intermediate frequency amplification and filtering branch, and finally become a 200Mhz calibration intermediate frequency signal, which is sent to the 36-channel AD sampling port of the signal processing board;

[0043] S6. The 36-channel AD sampling module of the signal processing board samples the calibration intermediate frequency signal, completes the FFT signal processing algorithm inside the signal processing board, extracts the amplitude and phase characteristic information, and stores it;

[0044] S7. The signal processing board enables the frequency synthesizer to work in the receive even calibration working mode;

[0045] S8. The frequency synthesizer up-converts the calibration intermediate frequency 200Mhz signal to a 5.2Ghz RF signal, passes through the calibration RF channel, first passes through the even calibration output, is transmitted in the even calibration branch of the power division network, and finally radiates from the even calibration antenna to the antenna stand array, and then repeats S5-S6;

[0046] S9. When the calibration antenna stand array is transmitting, the signal processing board is in the calibration time slice, and the DA generates a point frequency signal with a fixed frequency of 200Mhz, an amplitude of 0dBm, a phase of 0°, and a time width of 20us, which is output to the intermediate frequency signal input interface socket of the frequency synthesizer through the amplifier, bandpass filter, and SMA socket;

[0047] S10. The frequency synthesizer up-converts the calibration intermediate frequency 200Mhz signal to a 5.2Ghz RF signal, passes through the excitation channel, and through the power division network, and is sent to the excitation port of the antenna stand array;

[0048] S11. The antenna stand array opens the transmission channel in turn, radiates the calibration RF 5.2Ghz signal through the printed antenna, receives the calibration signal through the calibration branch of the power division network, and transmits it to the frequency synthesizer calibration interface;

[0049] S12. The frequency synthesizer is in the calibration receiving mode, and the calibration RF 5.2Ghz signal is down-mixed to the intermediate frequency 200Mhz signal and sent to the AD sampling port of the signal processing board;

[0050] S13. The signal processing board completes AD sampling and signal processing, calculates the amplitude and phase information of the signal, and stores it;

[0051] S14. After completing the above operations, the amplitude phase difference is calculated by comparing it with the reference data amplitude phase value detected by the internal antenna stand array calibration. If the difference exceeds the threshold, the self-test channel is judged to be abnormal and the fault is reported. If the difference does not exceed the threshold, it is converted into the compensation code value of the antenna stand phase shifter and attenuator to complete the self-calibration of the antenna stand array receiving channel.

Claims

1. A circular array radar antenna assembly online self-test and amplitude and phase self-calibration system, characterized in that: The radar is integrated with special self-test and self-calibration functions. External calibration antennas are installed around the base of the equipment cage. Special calibration channels are added to the power division network, special calibration modules are added to the frequency synthesizer, and calibration modes are added to the signal processing board. Self-test and self-calibration time slices are inserted into the timing sequence, and the calibration signals are generated and received by using its own hardware conditions to complete the online self-test and amplitude and phase self-calibration of the circular array radar antenna components.

2. The circular array radar antenna assembly self-test and amplitude and phase self-calibration system according to claim 1, characterized in that: The external calibration antenna is composed of multiple waveguide antennas, which are evenly arranged around the bottom of the frustum array. Each external calibration antenna is responsible for calibrating the adjacent antenna stand array. The relative position relationship between the external calibration antenna and each front-end channel remains unchanged, and the amplitude-phase relationship is relatively fixed.

3. The circular array radar antenna assembly self-test and amplitude and phase self-calibration system according to claim 1, characterized in that: The dedicated calibration channel added to the power division network connects the external calibration antenna to the frequency synthesizer to complete the transmission of the calibration radio frequency signal.

4. The circular array radar antenna assembly self-test and amplitude and phase self-calibration system according to claim 3, characterized in that: The power division network adopts Wilkinson microstrip line power divider.

5. The circular array radar antenna assembly self-test and amplitude and phase self-calibration system according to claim 1, characterized in that: The frequency synthesizer is added with a special calibration module to realize signal amplification, filtering, up-down mixing, image frequency suppression and switching of the transmitting and receiving channels.

6. The circular array radar antenna assembly self-test and amplitude and phase self-calibration system according to claim 1, characterized in that: The signal processing board is responsible for timing generation, enabling frequency synthesizer working mode switching, controlling ADC and DAC, and completing multi-channel intermediate frequency calibration signal generation and collection.

7. The circular array radar antenna assembly self-test and amplitude and phase self-calibration system according to claim 1, characterized in that: The calibration mode includes transmission calibration and reception calibration, inserts self-check and self-calibration time slices in the timing sequence, and uses its own hardware conditions to complete the self-check and amplitude and phase self-calibration of the transmission and reception channels of the antenna array TR component.

8. A self-calibration method based on the circular array radar antenna assembly self-checking and amplitude and phase self-calibration system according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. During the self-check and self-calibration of the antenna stand array receiving channel, the signal processing board enables the frequency synthesizer to work in the receiving calibration working mode during the calibration time slice; S2. The signal processing board enables the DA to generate a fixed amplitude and phase point frequency signal during the calibration time slice and outputs it to the frequency synthesizer; S3. The frequency synthesizer up-converts the calibration intermediate frequency signal to an RF signal, outputs it through the calibration RF channel, transmits it in the calibration branch of the power division network, and finally radiates it to the antenna stand array through the calibration antenna; S4. The antenna array receives the calibration RF signal, which passes through the receiving branch of the transceiver component, the power divider, the down-mixer, the intermediate frequency amplification and filtering branch in sequence, and finally becomes a calibration intermediate frequency signal, which is sent to the AD sampling port of the signal processing board; S5. The AD sampling module of the signal processing board samples the calibration intermediate frequency signal, completes FFT signal processing inside the signal processing board, extracts the amplitude and phase characteristic information of the antenna array receiving channel, and stores it; S6. During the self-check and self-calibration of the antenna stand array transmission channel, the signal processing board is in the calibration time slice, enabling the frequency synthesizer to work in the transmission calibration working mode; S7. The signal processing board enables the DA to generate a fixed amplitude and phase point frequency signal during the calibration time slice and outputs it to the frequency synthesizer; S8. The frequency synthesizer up-converts the calibration intermediate frequency signal to a radio frequency signal, outputs it through the excitation channel, passes through the power division network, and is sent to the excitation port of the antenna stand array; S9. The antenna stand array opens the transmission channel in turn, radiates the calibration RF signal through the antenna, receives the calibration signal through the calibration branch of the power division network, and transmits it to the frequency synthesizer calibration interface; S10. The frequency synthesizer mixes the calibration RF signal down to an intermediate frequency signal and sends it to the AD sampling port of the signal processing board; S11. The signal processing board completes AD sampling and signal processing, calculates the amplitude and phase information of the antenna array transmission channel, and stores it; S12. After completing the above operations, the amplitude and phase values ​​are compared with the basic data obtained in the same way as in the microwave darkroom and pre-stored in the FLASH as a reference, and the difference in amplitude and phase is calculated; if the difference exceeds the threshold, the self-test channel is judged to be abnormal and the fault is reported; if the difference does not exceed the threshold, it is converted into the compensation code value of the antenna stand phase shifter and attenuator to complete the self-calibration of the antenna stand array receiving channel.

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