Holographic staring radar calibration method, device and system

Abstract

The invention relates to the technical field of radars, discloses a holographic staring radar calibration method, device and system, and aims to systematically calibrate the whole holographic staring radar in an external field in a low-cost and high-degree-of-freedom manner. The phase shifter comprises a receiving antenna, a transmitting antenna, a main control chip, a radio frequency gain chip and a phase shifting chip, data connection is established between the phase shifting chip and the radio frequency gain chip, and signaling connection is established between the main control chip and the radio frequency gain chip and the phase shifting chip. The main control chip is used for instructing the phase shift chip to dynamically switch a continuous detection signal transmitted by the radar between a phase shift processing mode and a non-phase-shift signal straight-through processing mode according to a pulse repetition period; and the radio frequency gain chip performs undifferentiated processing on the input signal subjected to phase shift or direct connection processing of the phase shift chip and then outputs the input signal.

Description

Technical Field

[0001] The present invention relates to the field of radar calibration technology, and in particular to a holographic staring radar calibration method, device and system. Background Art

[0002] In a holographic staring radar, there will always be large amplitude and phase differences between different channels due to the amplitude and phase inconsistency of multiple channels of the device, the amplitude and phase inconsistency in the wiring of the RF cable, the amplitude and phase inconsistency between the antenna channels, etc. The amplitude and phase consistency of each channel is closely related to the angle measurement of the radar. If the amplitude and phase of each channel are inconsistent, it will cause serious angle measurement errors.

[0003] At present, there are mainly the following methods for the amplitude and phase consistency and angle calibration of holographic staring radar: First, by designing an additional coupling port for the antenna in the early stage, each antenna array element is connected to the coupling port through a power divider, and then coupled to the antenna port through the transmitting end. However, this method cannot calibrate the amplitude and phase errors introduced from the antenna radiating end to the ports of the antenna channel.

[0004] Second, scan in a darkroom and complete calibration measurements through antenna diagrams. This method requires a large darkroom for wide-beam radar measurements, which results in a large workload and high testing costs.

[0005] 3. Use far-field cooperative targets for detection. The far-field cooperative target can be a drone. Then compare the drone’s actual track data with the radar test track data to obtain the amplitude and phase calibration and the azimuth and pitch coefficient matrix. However, this measurement and calibration requires the drone to be able to fly in most of the airspace detected by the radar, and the drone’s trajectory data and the radar’s stored data must be strictly aligned, which has high requirements for the site and equipment.

[0006] Therefore, the prior art still lacks a device for radar field calibration, which can systematically calibrate the entire holographic staring radar in the field in a low-cost and high-degree-of-freedom manner. Summary of the invention

[0007] The present invention aims to disclose a holographic staring radar calibration method, device and system, which can systematically calibrate the entire holographic staring radar in an outdoor field in a low-cost and high-degree-of-freedom manner.

[0008] To achieve the above-mentioned purpose, the present invention discloses a phase shifter, comprising a receiving antenna, a transmitting antenna, a main control chip, a radio frequency gain chip and a phase shift chip, wherein a data connection is established between the phase shift chip and the radio frequency gain chip, and a signaling connection is established between the main control chip, the radio frequency gain chip and the phase shift chip. The main control chip is used to instruct the phase shift chip to dynamically switch between two modes of phase shift processing and signal direct processing without phase shifting for a continuous detection signal emitted by a radar according to a pulse repetition period, and enables the radio frequency gain chip to perform indifferent processing on the input signal after phase shifting or direct processing by the phase shift chip and then output it.

[0009] Preferably, an input filter chip is provided between the phase shift chip and the receiving antenna. Similarly, further, an output filter chip may be provided between the RF gain chip and the transmitting antenna.

[0010] To achieve the above object, the present invention further discloses a holographic staring radar calibration method, comprising: Step S1, placing the phase shifter as described above at a calibration position.

[0011] Step S2: after the phase shifter is stabilized at the calibrated position, the holographic staring radar system is started; and after the holographic staring radar system detects the phase shifter, measurement data is obtained according to the detection signal emitted by the radar and the echo signal returned by the phase shifter.

[0012] Step S3: realize the overall calibration of the radar external field according to the measured data and the actual data.

[0013] In the method of the present invention, preferably, there are at least two calibration positions corresponding to the phase shifter. In step S3, the amplitude and phase responses of each channel are first adjusted to be consistent based on any calibration position; then, the measurement data of the azimuth and elevation angles of each calibration position are collected and calculated based on the calibrated amplitude and phase parameters of each channel; then, iterative adjustment is performed based on the measurement data corresponding to the azimuth and elevation angles of each calibration position and the actual data, so as to minimize the root mean square error of the two error sequences of the azimuth and elevation angles.

[0014] The process of adjusting the amplitude and phase responses of each channel to be consistent based on any calibration position specifically includes: Assume that the echo data of radar channel C is expressed as follows: ; in, Indicates The echo data of the radar channel, and Indicates channel The amplitude and phase values ​​of all channels are taken, and the average value of the radar echo amplitude is taken, and the amplitude data of each channel is multiplied by each amplitude calibration coefficient to adjust to the average value of the radar echo amplitude. Then, the channel with the smallest amplitude is used as the phase adjustment point, and the phases of all other channels are adjusted to the same phase value of this channel, as shown in the following formula: ; in, Indicates Amplitude calibration coefficients for each channel, Indicates Phase calibration coefficients for each channel, Indicates the calibration The echo data of channels, and The calculation formula is: ; .

[0015] Furthermore, the method of the present invention can use a linear regression model to implement iterative adjustment of the azimuth angle and the elevation angle, specifically including: The average value of the azimuth error of the series of calibration positions is taken as the overall azimuth system error, which is used as the bias term of linear regression. , take the ratio of the minimum error value to the total error value as the initial regression coefficient , then the linear regression model can be expressed as follows: ; in, Indicates The measured data after position adjustment is the azimuth or elevation angle of the calibrated position of the phase shifter. and represents the amplitude and phase value of the phase shifter, Indicates the selected angle measurement algorithm; in order to find an optimal regression coefficient, the minimum root mean square error is used as the loss function , as follows: ; in, represents the number of phase shifters at different calibration positions, Indicates The true value of the position; then use the gradient descent method to adjust the parameters, and the update formula is: ; in, express or , represents the learning rate, Indicates the next iteration after update .

[0016] Preferably, the method of the present invention is relative to the radar echo data of the phase shifter target The expression is as follows: ; in, Indicates Pulses, is the bandwidth of the radar transmission signal, is the pulse width of the radar transmitting signal, Indicates Fast time echo data of pulses, Indicates the phase size changed by the phase shifter, Indicates how much time it takes for the radar signal to return to the radar after it is sent to the phase shifter target. represents the scattering coefficient of the target, represents the RF gain of the phase shifter.

[0017] To achieve the above-mentioned purpose, the present invention further discloses a holographic staring radar calibration system, comprising the phase shifter and radar host computer as described above.

[0018] The present invention has the following beneficial effects: The traditional phase shifter is only equivalent to the phase shift chip of the present invention, which is usually only deployed inside the radar to perform indiscriminate phase shifting operations on the matching input or output signals. In contrast, the present invention ingeniously assembles the phase shift chip with the transceiver antenna, the main control chip and the auxiliary processing circuits around the RF gain matching into an independent product. When used as an auxiliary device for radar field calibration, it can dynamically switch between the two modes of phase shift processing and non-phase shifted signal direct processing for the continuous detection signal emitted by the radar according to the pulse repetition period, and make the RF gain chip perform indiscriminate processing on the input signal after phase shift or direct processing of the phase shift chip and then output it; it can ensure that the calibrated signal is clearly displayed on the radar host computer and complete the collection of measurement data; thus, the overall holographic staring radar can be systematically calibrated in the field in a low-cost and high-degree-of-freedom manner.

[0019] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 It is a block diagram of the architecture of the phase shifter disclosed in the embodiment of the present invention.

[0021] Figure 2 It is an overall block diagram of the holographic staring radar calibration system disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The embodiments of the present invention are described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0023] Example 1 This embodiment discloses a phase shifter, such as Figure 1 As shown, it includes a receiving antenna, a transmitting antenna, a main control chip, a RF gain chip and a phase shift chip, wherein the phase shift chip is linked to the RF gain chip by an RF link, and the main control chip establishes communication connections with the RF gain chip and the phase shift chip. The main control chip is used to instruct the phase shift chip to dynamically switch between two modes of phase shift processing and signal direct processing without phase shifting for the continuous detection signal emitted by the radar according to the pulse repetition period, and enables the RF gain chip to perform indifferent processing on the input signal after phase shifting or direct processing of the phase shift chip and then output it.

[0024] Preferably, an input filter chip is provided between the phase shift chip and the receiving antenna. Similarly, further, an output filter chip may be provided between the RF gain chip and the transmitting antenna.

[0025] Among them, the design points of each component module of the phase shifter are as follows: 1. Receiving antenna. Due to the uncertainty of the external environment, the best antenna is an omnidirectional antenna, which can receive the signal sent by the radar within the maximum range. And according to the different bands of the calibrated holographic staring radar, the antenna also needs to match radars of different bands.

[0026] 2. The phase shift module should provide 360-degree phase coverage, have extremely low phase error and small insertion loss. The frequency band used should also be the same as the radar frequency band. The control logic should be simple and convenient, preferably the same as the control logic of the signal amplification module, so as to facilitate simultaneous control of signals and phase shifting. The HMC647ALP6E chip can be selected.

[0027] 3. Signal amplification module. Different types of gain chips can be selected according to the main usage scenarios. If the radar transmission power is small or the calibration site is far away, a high-power amplifier can be selected in this module. If the calibration scenario has complex electromagnetic environment interference, etc., a low-noise amplifier can be selected. The selected frequency should be the same as the radar band to prevent other interference signals except the radar signal from interfering with the radar reception after passing through the amplification module, thereby reducing the calibration accuracy. The power gain needs to be selected according to the actual usage scenario. Its control logic should be the same as the control logic of the phase shifter to facilitate simultaneous control.

[0028] 4. The choice of main control chip is diversified. You can choose any specification of microcontroller for control, such as 51 microcontroller, GD32, STM32, ESP32 microcontroller and Arduino, etc. You can also use programmable devices such as FPGA to control the phase shift chip and signal amplification module.

[0029] 5. The selection of transmitting antenna is similar to that of receiving antenna. Select an omnidirectional antenna with the same frequency band as the radar frequency band.

[0030] In addition, different phase shift configurations are selected according to the radar system. For example, a pulse radar transmits a signal according to PRF (Pulse repetition frequency). After the phase shifter receives the signal, it performs a phase shift function in the next cycle according to the frequency of PRF. For example, you can choose to perform an inverted or orthogonal signal and then transmit it to the transmitting antenna through a signal amplification module, etc. For example, for a continuous wave radar, you can choose to use the length of the transmitting pulse, that is, the pulse width, as a period to adjust its phase.

[0031] In summary, when selecting a specific chip, Figure 1 As shown, the filter chip can be JY-BFCN-3010+, the phase shift chip can be HMC647ALP6E, the RF gain chip can be HG124FD, and the main control chip can be STM32F103C8T6.

[0032] Example 2 In this embodiment, the phase shifter in Embodiment 1 is used for holographic staring radar calibration, and the calibration method specifically includes: Step S1, placing the phase shifter in a calibration position, wherein the "calibration position" is also referred to as a "preset position", which will not be described in detail later.

[0033] Step S2: after the phase shifter is stabilized at the calibrated position, the holographic staring radar system is started; and after the holographic staring radar system detects the phase shifter, measurement data is obtained according to the detection signal emitted by the radar and the echo signal returned by the phase shifter.

[0034] Step S3: realize the overall calibration of the radar external field according to the measured data and the actual data.

[0035] In the method of this embodiment, preferably, there are at least two calibration positions corresponding to the phase shifter. In step S3, the amplitude and phase responses of each channel are first adjusted to be consistent based on any calibration position; then, the measurement data of the azimuth and elevation angles of each calibration position are collected and calculated based on the calibrated amplitude and phase parameters of each channel; then, iterative adjustment is performed based on the measurement data corresponding to the azimuth and elevation angles of each calibration position and the actual data, so as to minimize the root mean square error of the two error sequences of the azimuth and elevation angles.

[0036] Further, in the specific operation process, refer to Figure 2 , detailed guidance can be provided based on the following: In the field calibration of the holographic staring radar system of this embodiment, the phase shifter is used as the reference source, and the measurement data collected at the fixed known position of the phase shifter is used to calculate the corresponding amplitude-phase characteristic matrix. The matrix is ​​expressed as the number of channels × the number of pulses × the number of sampling points, and finally the optimal calibration coefficient is obtained. Then, the azimuth and pitch of the phase shifter are calculated through the amplitude-phase characteristics between channels to achieve accurate calibration between channels.

[0037] To this end, at the beginning of the calibration phase, two core matrices are first constructed: Truth matrix: Based on the known fixed position of the phase shifter, its precise distance, azimuth and elevation relative to the radar are calculated through GPS and altitude, and recorded as the truth matrix M T The truth matrix contains the true distance information of the phase shifter, which serves as the reference for the target of inter-channel calibration. This matrix ensures that we can verify the consistency of the measurement target through subsequent channel measurement comparison.

[0038] Measurement matrix: Generate the measurement matrix M using the radar system’s measurement data of the phase shifter E , records the phase shifter measurement information of the radar under the current conditions and the amplitude and phase characteristic information of each channel. This matrix contains the radar's measurement distance information, measurement azimuth information, and measurement pitch information of the phase shifter. During the calibration process, by comparing the distance information of the true value matrix with the distance information of the measurement matrix, it can be confirmed whether the measurement object of each channel is the expected target, thereby ensuring the accuracy of the calibration data.

[0039] After confirming that each channel measures the same target (phase shifter), the next step is to calculate the amplitude and phase calibration coefficients for each channel. Here, the radar echo data expression is added. Assuming that the linear frequency modulation signal is used as the radar's transmitting signal, the expression of its transmitting signal is as follows: .

[0040] in, represents the amplitude of the transmitted signal, It represents the fast time, i.e. the sampling time when the radar transmits a single pulse. Expressed as the center frequency of the radar, is the bandwidth of the radar transmission signal, Indicates the time width of the radar transmitted signal, that is, the pulse width.

[0041] The radar detects the phase shifter target. After the phase shifter target reflects the radar's transmission signal, the target's echo pulse can be expressed as: .

[0042] in, Indicates how much time it takes for the radar signal to return to the radar after it is sent to the phase shifter target. represents the scattering coefficient of the target, represents the RF gain of the phase shifter.

[0043] The above is the echo data of a single pulse. Generally, radars do not only transmit single pulses for detection, but also transmit multiple pulses at one time, and then detect through multi-pulse accumulation. If multiple pulses are accumulated, the radar echo data relative to the phase shifter target is The expression is: .

[0044] in, Indicates Pulses, is the bandwidth of the radar transmission signal, is the pulse width of the radar transmitting signal, Indicates Fast time echo data of pulses, Indicates the phase size changed by the phase shifter, Indicates how much time it takes for the radar signal to return to the radar after it is sent to the phase shifter target. represents the scattering coefficient of the target, represents the RF gain of the phase shifter.

[0045] Each channel has quantifiable unique amplitude and phase characteristics due to layout differences, but there are usually some unpredictable differences due to hardware or RF cables. Calculating these amplitude and phase calibration coefficients helps quantify the amplitude and phase relationship between different channels, thereby improving the detection accuracy of the radar.

[0046] Based on the amplitude and phase calibration coefficients, the optimal calibration coefficients of each channel are calculated through the angle error matrix and optimization algorithm to ensure the overall measurement consistency of the system. Through the optimization algorithm, the optimal proportional relationship between the amplitude and phase calibration coefficients of each channel is established. Taking the method of aligning the amplitude and phase of a single channel as an example, how to calculate the preliminary amplitude and phase calibration coefficients is explained, assuming that the echo data of radar channel C is expressed as follows: .

[0047] in, Indicates The echo data of the radar channel, and Indicates channel The amplitude and phase values ​​of all channels are taken, and the average value of the radar echo amplitude is taken, and the amplitude data of each channel is multiplied by each amplitude calibration coefficient to adjust to the average value of the radar echo amplitude. Then, the channel with the smallest amplitude is used as the phase adjustment point, and the phases of all other channels are adjusted to the same phase value of this channel, as shown in the following formula: .

[0048] in, Indicates Amplitude calibration coefficients for each channel, Indicates Phase calibration coefficients for each channel, Indicates the calibration The echo data of channels, and The calculation formula is: ; .

[0049] The calculated calibration coefficients can be applied to each channel, thereby preliminarily eliminating the amplitude and phase deviations between channels that are inconvenient to quantify in field experiments. These calibration coefficients ensure that the system can provide consistent amplitude and phase responses when measuring multiple channels, so that the measurement results of the same target remain consistent in each channel.

[0050] After completing the preliminary amplitude and phase calibration, the azimuth and elevation angle errors are calculated based on the calibrated channel data.

[0051] Azimuth error calculation: Based on the amplitude and phase data of each channel after preliminary correction, the azimuth of different preset positions can be calculated through angle measurement algorithms (such as single pulse angle measurement and difference beam angle measurement, etc.).

[0052] .

[0053] in, Indicated in The radar at a preset position calculates the angle of the phase shifter based on the calibrated amplitude and phase data. and Indicates Amplitude and phase calibration coefficients for each position (all channels of the radar must be collected at each position), and Indicates The original amplitude and phase values ​​of the positions indicate the angle measurement algorithm selected according to the amplitude and phase values ​​of the phase shifter target, and the azimuth and elevation true values ​​of the target are taken out from the phase shifter true value matrix constructed previously. T Similarly, the angle of the phase shifter at each position is calculated, and then the azimuth angle error sequence of the radar in this azimuth can be obtained. , ;in, For the The true value of the position azimuth.

[0054] The principle of pitch error calculation is similar to that of azimuth error, so it will not be elaborated here.

[0055] The two error sequences are combined into an angle error matrix, and then iterative optimization is performed through algorithms such as linear regression. The iteration parameters are the preliminary amplitude and phase calibration coefficients, and the iteration goal is to minimize the root mean square error of the angle error matrix, that is, the two error sequences. The iterative optimization process is as follows: To ensure the validity of the optimal calibration coefficient and the accuracy of the angle measurement, multiple iterative optimizations can be performed after the initial calibration is completed. It is assumed that the optimization goal is to minimize the root mean square error of the two error sequences.

[0056] Feedback correction: The calculated azimuth and pitch errors are fed back to the system to correct the calibration coefficients calculated initially, and the amplitude and phase calibration data of each channel are readjusted according to the calibration coefficients.

[0057] Iterative convergence: Repeat the above calibration and error calculation process until the change amplitude of the azimuth and elevation errors of the entire radar system converges to an acceptable range, thereby obtaining the final optimal calibration coefficient.

[0058] Final optimization effect: Through multiple iterations of optimization, the system calibration coefficient and angle error are ensured to be optimal, so as to provide high-precision azimuth and elevation measurement capabilities. This iterative process is an important step to ensure that the holographic staring radar can maintain high-precision angle measurement in complex environments.

[0059] Taking linear regression as an example (the iterative optimization algorithm can be selected according to the angle measurement algorithm), the iterative process is sorted out: The average value of the azimuth error of the series of calibration positions is taken as the overall azimuth system error, which is used as the bias term of linear regression. , take the ratio of the minimum error value to the total error value as the initial regression coefficient , then the linear regression model can be expressed as follows: .

[0060] in, Indicates The measured data after position adjustment is the azimuth or elevation angle of the calibrated position of the phase shifter. and represents the amplitude and phase value of the phase shifter, Indicates the angle measurement algorithm selected (when processing azimuth, it is the above ); In order to find an optimal regression coefficient, minimize the root mean square error as the loss function , as follows: .

[0061] in, represents the number of phase shifters at different calibration positions, Indicates The true value of the position; then use the gradient descent method to adjust the parameters, and the update formula is: .

[0062] in, express or , represents the learning rate, Indicates the next iteration after update .

[0063] Furthermore, the following is a brief recap of the above calibration steps using an 8-channel radar as an example: 1. Use the phase shifter to preset 25 positions and stipulate that the angle to the left of the radar centerline is a negative angle. The angles of the 13 positions are -60°, -55°, -50°, -45°, -40°, -35°, -30°, -25°, -20°, -15°, -10°, -5°, 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°. Each position uses the GPS coordinates in the WGS84 coordinate system and corresponds to the position of the radar to obtain the truth matrix M. T .

[0064] 2. Start the radar and collect data on the phase shifter target to obtain the radar raw data Mr. Perform preliminary raw data correction on the eight channels of the radar according to the amplitude and phase characteristics of the phase shifter. The correction coefficients of the eight channels are ( , )-( , ), assuming that the radar data after preliminary correction For example, the phase angles of channels 1-8 are 34.7°, 152.3°, 267.8°, 89.5°, 315.2°, 176.9°, 45.1°, and 298.4°, and the minimum phase value is 34.7°. The phase of channel 2 is 152.3°, and the phase calibration value of channel 2 is -117.6°.

[0065] 3. Based on the corrected radar data , through the common angle measurement algorithm, the radar's measured azimuth angle sequence of the phase shifter is calculated, and the azimuth error of the correction coefficient is obtained by comparing the measured azimuth angle with the actual angle. Similarly, the error in pitch is obtained. For example: Assuming that the value of each preset position calculated by the angle measurement algorithm is -59.3°, -54.7°, -49.2°, -44.8°, -39.1°, -34.6°, -29.4°, -24.9°, -19.7°, -14.3°, -9.8°, -4.5°, 0.7°, 5.2°, 10.6°, 15.3°, 20.8°, 25.1°, 30.5°, 35.7°, 40.4°, 45.9°, 50.3°, 55.6° and 60.9°, then the mean error is The minimum error is 0.508. That is 0.1.

[0066] 4. According to the above azimuth error and pitch error sequence, the preliminary linear regression coefficient is calculated, and the linear regression coefficient is solved according to the true value and the measured value. Finally, the parameters are adjusted by minimizing the root mean square error as the loss function and gradient descent. Iterate until it converges to a stable value and obtains the optimal linear regression coefficient. For example, the parameter value of the last iteration is is 0.503, the coefficient It is 0.008.

[0067] As a workaround, in some other implementation scenarios, other curve fitting methods may be used to replace the above linear regression model.

[0068] Example 3 This embodiment discloses a holographic staring radar calibration system, including the phase shifter as described in Example 1, and a radar host computer for executing the method as described in Example 2.

[0069] In summary, the methods, devices (i.e., phase shifters), and systems disclosed in the embodiments of the present invention respectively have at least the following beneficial effects: The traditional phase shifter is only equivalent to the phase shift chip of the present invention, which is usually only deployed inside the radar to perform indiscriminate phase shifting operations on the matching input or output signals. In contrast, the present invention ingeniously assembles the phase shift chip with the transceiver antenna, the main control chip and the auxiliary processing circuits around the RF gain matching into an independent product. When used as an auxiliary device for radar field calibration, it can dynamically switch between the two modes of phase shift processing and non-phase shifted signal direct processing for the continuous detection signal emitted by the radar according to the pulse repetition period, and make the RF gain chip perform indiscriminate processing on the input signal after phase shift or direct processing of the phase shift chip and then output it; it can ensure that the calibrated signal is clearly displayed on the radar host computer and complete the collection of measurement data; thus, the overall holographic staring radar can be systematically calibrated in the field in a low-cost and high-degree-of-freedom manner.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A phase shifter, characterized in that: The invention comprises a receiving antenna, a transmitting antenna, a main control chip, a radio frequency gain chip and a phase shift chip, wherein a data connection is established between the phase shift chip and the radio frequency gain chip, and a signaling connection is established between the main control chip, the radio frequency gain chip and the phase shift chip. The main control chip is used to instruct the phase shift chip to dynamically switch between two modes of phase shift processing and signal direct processing without phase shifting for the continuous detection signal emitted by the radar according to the pulse repetition period, and enables the radio frequency gain chip to perform indifferent processing on the input signal after phase shifting or direct processing of the phase shift chip and then output it.

2. The phase shifter according to claim 1, characterized in that: An input filter chip is provided between the phase shift chip and the receiving antenna.

3. The phase shifter according to claim 1 or 2, characterized in that: An output filter chip is provided between the radio frequency gain chip and the transmitting antenna.

4. A holographic staring radar calibration method, characterized in that: include: Step S1, placing the phase shifter as claimed in any one of claims 1 to 3 at a calibration position; Step S2, after the phase shifter is stabilized at the calibrated position, the holographic staring radar system is started; and after the holographic staring radar system detects the phase shifter, measurement data is obtained according to the detection signal emitted by the radar and the echo signal returned by the phase shifter; Step S3: realize the overall calibration of the radar external field according to the measured data and the actual data.

5. The method according to claim 4, characterized in that There are at least two calibration positions corresponding to the phase shifter. In step S3, the amplitude and phase responses of each channel are first adjusted to be consistent based on any calibration position; then, the measurement data of the azimuth and elevation angles of each calibration position are collected and calculated based on the calibrated amplitude and phase parameters of each channel; then, iterative adjustment is performed based on the measurement data and actual data corresponding to the azimuth and elevation angles of each calibration position, so as to minimize the root mean square error of the two error sequences of the azimuth and elevation angles.

6. The method according to claim 5, characterized in that The process of adjusting the amplitude and phase responses of each channel to be consistent based on any calibration position specifically includes: Assume that the echo data of radar channel C is expressed as follows: ； in, Indicates The echo data of the radar channel, and Indicates channel The amplitude and phase values ​​of all channels are taken, and the average value of the radar echo amplitude is taken, and the amplitude data of each channel is multiplied by each amplitude calibration coefficient to adjust to the average value of the radar echo amplitude. Then, the channel with the smallest amplitude is used as the phase adjustment point, and the phases of all other channels are adjusted to the same phase value of this channel, as shown in the following formula: ； in, Indicates Amplitude calibration coefficients for each channel, Indicates Phase calibration coefficients for each channel, Indicates the calibration The echo data of channels, and The calculation formula is: ; .

7. The method according to claim 5, characterized in that The linear regression model is used to implement iterative adjustment of azimuth and elevation angles, including: The average value of the azimuth error of the series of calibration positions is taken as the overall azimuth system error, which is used as the bias term of linear regression. , take the ratio of the minimum error value to the total error value as the initial regression coefficient , then the linear regression model can be expressed as follows: ； in, Indicates The measured data after position adjustment is the azimuth or elevation angle of the calibrated position of the phase shifter. and represents the amplitude and phase value of the phase shifter, Indicates the selected angle measurement algorithm; in order to find an optimal regression coefficient, the minimum root mean square error is used as the loss function , as follows: ； in, represents the number of phase shifters at different calibration positions, Indicates The true value of the position; then use the gradient descent method to adjust the parameters, and the update formula is: ； in, express or , represents the learning rate, Indicates the next iteration after update .

8. The method according to any one of claims 4 to 7, characterized in that: Radar echo data relative to phase shifter target The expression is as follows: ； in, Indicates Pulses, is the bandwidth of the radar transmission signal, is the pulse width of the radar transmitting signal, Indicates Fast time echo data of pulses, Indicates the phase size changed by the phase shifter, Indicates how much time it takes for the radar signal to return to the radar after it is sent to the phase shifter target. represents the scattering coefficient of the target, represents the RF gain of the phase shifter.

9. A holographic staring radar calibration system, characterized in that: It comprises a phase shifter as claimed in any one of claims 1 to 3, and a radar host computer for executing any one of claims 4 to 8.

Images