Calibration method based on multi-input multi-output phased array radar system

Abstract

The invention relates to the technical field of phased array radars, and discloses a calibration method based on a multi-transmitting multi-receiving phased array radar system, which comprises transmitting channel calibration and receiving channel calibration: during transmitting channel calibration, retaining transmitting channels group by group, closing other transmitting channels, and performing measurement calibration, determining the calibration coefficient of the transmitting channel under each frequency point until all the transmitting channels are traversed; and when the receiving channels are calibrated, the receiving channels are reserved group by group, other receiving channels are closed, and measurement calibration is carried out until all the receiving channels are traversed, and then the calibration coefficient of the receiving channel under each frequency point is determined. According to the invention, an antenna radiation array, a calibration network, a wave controller, a channel extension set and a signal processing extension set can be calibrated from the perspective of a whole machine, and calibration from a single component is avoided; amplitude and phase calibration is carried out on receiving and transmitting of the system by using a single calibration channel, coherence of calibration results is ensured by using the same pulse string, and consumption of hardware resources is reduced.

Description

Technical Field

[0001] This invention relates to the field of phased array radar technology. Background Technology

[0002] With the development of electronic countermeasures technology, the electronic environment faced by phased array radar systems is becoming increasingly complex. Employing a MIMO (Multi-Input Multiple-Output) system with multiple channels for transmission and reception can effectively combat radar interference. However, in practical engineering, the presence of numerous analog devices and active circuits in the phased array antenna and integrated channel leads to amplitude and phase inconsistencies between the transmission and reception channels, severely impacting the overall performance of the radar system. Therefore, further research is needed on calibration methods for MIMO phased array radar systems. This research aims to calibrate the transmission and reception amplitudes and phases of the MIMO phased array radar system while ensuring a minimum number of calibration channels, thereby guaranteeing the overall system performance.

[0003] Traditional phased array radar systems have seen extensive research on calibration methods for the transmit and receive channels of phased array antennas and core chips, but less research on calibration methods for multi-transmit / receiver (MMR) systems, which include phased array antennas, integrated channels, and signal processing. For example, in 2022, Yan Na et al. from Fudan University proposed a multi-channel phased array transmitter amplitude and phase calibration device and method. This method only considers RF transmission calibration and does not consider the overall radar system calibration method from the perspective of signal processing sub-units, nor does it analyze multi-channel reception. In 2023, Li Gewei from the University of Electronic Science and Technology of China proposed a research and implementation method for amplitude and phase inconsistency correction in multi-channel phased array radar. This system only studies multi-channel reception calibration methods and does not analyze the calibration methods for MMR systems. In 2024, Xia Jie et al. from Chongqing Mitian Communication Equipment Co., Ltd. proposed an amplitude and phase error calibration circuit for millimeter-wave band multi-channel phased array chips. This method focuses on the multi-channel transmit and receive of phased array chips and does not analyze the calibration methods for MMR systems. Summary of the Invention

[0004] The purpose of this invention is to provide a calibration method for a multi-transmitter, multi-receiver phased array radar system, which can minimize system costs and ensure the coherence of calibration results by using the same pulse train, thereby reducing the complexity of the calibration method.

[0005] To address the aforementioned technical problems, this invention provides a calibration method for a multi-transmitter, multi-receiver phased array radar system, comprising transmit channel calibration and receive channel calibration: during transmit channel calibration, transmit channels are retained in groups while other transmit channels are shut down, and measurement calibration is performed until all transmit channels are traversed and the calibration coefficient of the transmit channel at each frequency point is determined; during receive channel calibration, receive channels are retained in groups while other receive channels are shut down, and measurement calibration is performed until all receive channels are traversed and the calibration coefficient of the receive channel at each frequency point is determined.

[0006] The transmission channel calibration includes the following steps: S11, Switching Status: Switch the calibration channel to receive status; S12. Initial value: Set the sequence number i to 1 and the number of transmission channels to N; S13, Measurement and Calibration: Open the i-th group of transmission channels as the calibration channel, close the other transmission channels, and measure the amplitude and phase value Ti of the signal received by the calibration channel within one CPI; S14. End of judgment: Determine whether i is equal to N. If yes, proceed to the next step. Otherwise, increment i by 1 and return to step S12. S15. Determine the calibration coefficients: The calibration coefficients of the transmit channel at each frequency point are [1 TK2 TK3 …TKn].

[0007] The receiving channel calibration includes the following steps: S21, Switching Status: Switch the calibration channel to the transmit status; S22. Initial value: Set the sequence number i to 1 and the number of receiving channels to N; S23. Measurement and calibration: Open the i-th receiving channel as the calibration channel, close the other receiving channels, and measure the amplitude and phase value Ri of the signal received by the calibration channel within one CPI; S24. End of judgment: Determine whether i is equal to N. If yes, proceed to the next step. Otherwise, increment i by 1 and return to step S12. S25. Determine the calibration coefficients: The calibration coefficients of the receiving channel at each frequency point are [1 RK2 RK3 …RKn].

[0008] Each group of transmission channels contains one transmission channel.

[0009] Each group of receiving channels contains one receiving channel.

[0010] The calibration coefficient TKi for each transmission channel at each frequency point is the reciprocal of the amplitude and phase value Ti of the i-th transmission channel relative to the amplitude and phase value T(N-1) of other transmission channels: TKi=T(N-1) / Ti.

[0011] The calibration coefficient RKi for each frequency point receiving channel is the reciprocal of the amplitude and phase value Ri of the i-th receiving channel relative to the amplitude and phase value R(N-1) of other receiving channels: RKi=T(N-1) / Ti.

[0012] The number of transmit channels and receive channels is the same.

[0013] Before calibrating the transmit channel and the receive channel, the TR chip should be powered off after the entire device is powered on.

[0014] Compared with existing technologies, this invention can calibrate the antenna radiation array, calibration network, beam control, channel sub-unit, and signal processing sub-unit from the perspective of the whole machine, avoiding calibration from a single component. By using a single calibration channel, amplitude and phase calibration are performed on both the system's transmit and receive sides. By using the same pulse train, the coherence of the calibration results is guaranteed, reducing hardware resource consumption, reducing the use of additional instruments, improving calibration efficiency, and greatly reducing development costs.

[0015] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0017] Figure 1 This is a schematic diagram illustrating the principle of transmission channel calibration in at least one embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the principle of receiving channel calibration in at least one embodiment of the present invention; Figure 3 This is a schematic diagram of the architecture principle of a phased array radar system in at least one embodiment of the present invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the embodiments of this invention to facilitate a better understanding of this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this invention. The embodiments can be combined with and referenced by each other without contradiction.

[0019] Example 1 like Figure 1The calibration method shown is based on a multi-transmitter multi-receiver phased array radar system, including transmit channel calibration and receive channel calibration: During transmit channel calibration, transmit channels are retained in groups while other transmit channels are turned off, and measurement calibration is performed until all transmit channels are traversed and the calibration coefficient of the transmit channel at each frequency point is determined; During receive channel calibration, receive channels are retained in groups while other receive channels are turned off, and measurement calibration is performed until all receive channels are traversed and the calibration coefficient of the receive channel at each frequency point is determined.

[0020] Example 2 Based on Example 1, the transmission channel calibration includes the following steps: S11, Switching Status: Switch the calibration channel to receive status; S12. Initial value: Set the sequence number i to 1 and the number of transmission channels to N; S13, Measurement and Calibration: Open the i-th group of transmission channels as the calibration channel, close the other transmission channels, and measure the amplitude and phase value Ti of the signal received by the calibration channel within one CPI; S14. End of judgment: Determine whether i is equal to N. If yes, proceed to the next step. Otherwise, increment i by 1 and return to step S12. S15. Determine the calibration coefficients: The calibration coefficients of the transmit channel at each frequency point are [1 TK2 TK3 …TKn].

[0021] Furthermore, receiver channel calibration includes the following steps: S21, Switching Status: Switch the calibration channel to the transmit status; S22. Initial value: Set the sequence number i to 1 and the number of receiving channels to N; S23. Measurement and calibration: Open the i-th receiving channel as the calibration channel, close the other receiving channels, and measure the amplitude and phase value Ri of the signal received by the calibration channel within one CPI; S24. End of judgment: Determine whether i is equal to N. If yes, proceed to the next step. Otherwise, increment i by 1 and return to step S12. S25. Determine the calibration coefficients: The calibration coefficients of the receiving channel at each frequency point are [1 RK2 RK3 …RKn].

[0022] Furthermore, each group of launch channels contains one launch channel.

[0023] Furthermore, each group of receiving channels contains one receiving channel.

[0024] Example 3 Based on Example 2, the calibration coefficient TKi of the transmission channel at each frequency point is the reciprocal of the amplitude and phase value Ti of the i-th transmission channel relative to the amplitude and phase value T(N-1) of other transmission channels: TKi=T(N-1) / Ti.

[0025] Furthermore, the calibration coefficient RKi for each receiving channel at each frequency point is the reciprocal of the amplitude and phase value Ri of the i-th receiving channel relative to the amplitude and phase value R(N-1) of other receiving channels: RKi=T(N-1) / Ti.

[0026] Furthermore, the number of transmit channels and receive channels is the same.

[0027] Furthermore, before calibrating the transmit and receive channels, the TR chip should be powered off after the entire device is powered on.

[0028] Example 4 In conjunction with the above embodiments, such as Figure 3 As shown, the phased array radar system consists of an antenna radiating array, a calibration network, a waveguide, a channel unit, and a signal processing unit. It includes multiple transmit channels, multiple receive channels, and one calibration channel. The calibration network is composed of multiple bridge circuits, employs a waveguide structure, and has coupling capabilities. Except for the calibration network, the remaining parts of the antenna are already balanced.

[0029] The launch channel calibration process is as follows Figure 1 As shown. For more accurate testing, the calibration of the transmission channel must be performed in an anechoic chamber: Step 1: After assembling the entire unit, power it on and apply power to all TR chips; Step 2: Switch the calibration channel to receive mode. Close transmit channels 2 to N, and open transmit channel 1. The waveform is a sine wave; set parameters such as transmit excitation waveform pulse width, PRI, and CPI.

[0030] Step 3: Measure the amplitude and phase value T1 of the signal received by the calibration channel within one CPI; Step 4: Maintain the excitation and transmission state, close transmission channel 1, and open transmission channel 2. Measure the amplitude and phase value T2 of the signal received by the calibration channel; Step 5: Repeat step 4, maintaining the excitation and transmission state, and sequentially open channels 3 to N. Measure the amplitude and phase value Tn(T3-Tn) of the received signal in the calibration channel; Step 5: Using transmission channel 1 as a reference, calculate the ratio TK2 to TKn between the remaining transmission channel's Tn and the transmission channel 1's T1; Step 6: Repeat steps 2 to 5 according to the new frequency points to obtain T1 to Tn and TK2 to TKn at the remaining frequency points.

[0031] Finally, the calibration coefficients for the transmit channel at each frequency point are [1 TK2 TK3 … TKn].

[0032] The receiving channel calibration process is as follows: Figure 2 As shown: Step 1: After connecting all the wires, power on the device and power off all TR chips. Step 2: Switch the calibration channel to transmit mode. Open receive channels 1 to N, the waveform is a sine wave, and set parameters such as transmit excitation waveform pulse width, PRI, and CPI.

[0033] Step 3: Measure the amplitude and phase values ​​R1 to RN of the received signals from channels 1 to N respectively; Step 4: Using receiving channel 1 as a reference, calculate the ratio RK2 to RKn between the remaining receiving channel's Rn and the receiving channel 1's R1; Step 5: Repeat steps 2 to 5 according to the new frequency points to obtain R1 to RN and RK2 to RKn at the remaining frequency points.

[0034] Finally, the calibration coefficients for the receiving channel at each frequency point are [1 RK2 RK3 … RKn].

[0035] Therefore, in a multi-transmitter multi-receiver phased array radar system, this invention innovatively uses only one (group) calibration channel to calibrate the amplitude and phase of both the system's transmission and reception, reducing hardware resource consumption and greatly lowering development costs. When calibrating a single transmission channel, the use of the same pulse train ensures the coherence of the test results, reduces the use of additional instruments, improves calibration efficiency, avoids calibration from a single component, and improves the overall performance of the system.

[0036] Those skilled in the art will understand that the above embodiments can be modified in form and detail in practical applications without departing from the spirit and scope of the invention.

Claims

1. A calibration method based on a multi-transmitter, multi-receiver phased array radar system, characterized in that, This includes transmit channel calibration and receive channel calibration: During transmit channel calibration, transmit channels are kept in groups and other transmit channels are turned off, and measurement calibration is performed until all transmit channels are traversed and the calibration coefficient of the transmit channel at each frequency point is determined. During receiver channel calibration, receiver channels are kept in groups while other receiver channels are turned off, and measurement calibration is performed until all receiver channels are traversed and the calibration coefficient of the receiver channel at each frequency point is determined.

2. The calibration method for a multi-transmitter, multi-receiver phased array radar system as described in claim 1, characterized in that, The transmission channel calibration includes the following steps: S11, Switching Status: Switch the calibration channel to receive status; S12. Initial values: Set the sequence number i to 1 and the number of transmission channels to N; S13, Measurement and Calibration: Open the i-th group of transmission channels as the calibration channel, close the other transmission channels, and measure the amplitude and phase value Ti of the signal received by the calibration channel within one CPI; S14. End of judgment: Determine whether i is equal to N. If yes, proceed to the next step. Otherwise, increment i by 1 and return to step S12. S15. Determine the calibration coefficients: The calibration coefficients of the transmit channel at each frequency point are [1 TK2 TK3 … TKn].

3. The calibration method for a multi-transmitter, multi-receiver phased array radar system as described in claim 1, characterized in that, The receiving channel calibration includes the following steps: S21, Switching Status: Switch the calibration channel to the transmit status; S22. Initial value: Set the sequence number i to 1 and the number of receiving channels to N; S23. Measurement and calibration: Open the i-th receiving channel as the calibration channel, close the other receiving channels, and measure the amplitude and phase value Ri of the signal received by the calibration channel within one CPI; S24. End of judgment: Determine whether i is equal to N. If yes, proceed to the next step. Otherwise, increment i by 1 and return to step S12. S25. Determine the calibration coefficients: The calibration coefficients of the receiving channel at each frequency point are [1 RK2 RK3 … RKn].

4. The calibration method for a multi-transmitter, multi-receiver phased array radar system as described in claim 2, characterized in that, Each group of transmission channels contains one transmission channel.

5. The calibration method for a multi-transmitter, multi-receiver phased array radar system as described in claim 3, characterized in that, Each group of receiving channels contains one receiving channel.

6. The calibration method for a multi-transmitter, multi-receiver phased array radar system as described in claim 2, characterized in that, The calibration coefficient TKi for each transmission channel at each frequency point is the reciprocal of the amplitude and phase value Ti of the i-th transmission channel relative to the amplitude and phase value T(N-1) of other transmission channels: TKi=T(N-1) / Ti.

7. The calibration method for a multi-transmitter, multi-receiver phased array radar system as described in claim 3, characterized in that, The calibration coefficient RKi for each frequency point receiving channel is the reciprocal of the amplitude and phase value Ri of the i-th receiving channel relative to the amplitude and phase value R(N-1) of other receiving channels: RKi=T(N-1) / Ti.

8. The calibration method for a multi-transmitter, multi-receiver phased array radar system as described in claim 1, characterized in that, The number of transmit channels and receive channels is the same.

9. The calibration method for a multi-transmitter, multi-receiver phased array radar system as described in claim 1, characterized in that, Before calibrating the transmit channel and the receive channel, the TR chip should be powered off after the entire device is powered on.

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