Multi-channel phase calibration method and system based on detection target echo

Abstract

The invention relates to a multi-channel phase calibration method and system based on detection target echoes, belongs to the technical field of radar processing, and solves the problem that phase inconsistency of multiple channels of a radar caused by hardware difference cannot be efficiently solved in the prior art. The method comprises the specific steps that a radar system is triggered online to enter a real-time phase calibration mode; the method comprises the following steps: sequentially opening each emission channel of a radar system by using a time-sharing emission mechanism, radiating a radar pulse signal to a detection target, and respectively receiving an echo signal of the detection target to obtain an echo phase of each emission channel; performing phase calibration inversion based on each echo phase to obtain final compensation phases of each transmitting channel, and respectively issuing the final compensation phases to phase shifters of the corresponding transmitting channels; and recovering the calibration mode to a normal working mode, and taking the final compensation phase of each transmitting channel as the initial phase of the corresponding channel to perform phase adjustment, thereby realizing high-precision multi-channel online phase calibration.

Description

Technical Field

[0001] This invention relates to the field of radar processing technology, and in particular to a multi-channel phase calibration method and system based on the echo of a detected target. Background Technology

[0002] In modern communications, radar, electronic warfare, and other fields, it is often necessary to combine multiple signals to obtain higher output power. The core of a signal combining system is to superimpose the signals as much as possible in phase to achieve maximum combining efficiency. After a single signal is split into multiple signals by a power divider, each signal needs to be processed by devices such as power amplifiers and phase shifters before being combined. Due to hardware differences such as power amplifier discreteness, initial deviation of phase shifters, and link asymmetry, it is difficult to guarantee the phase consistency of the signals, leading to problems such as decreased combining efficiency.

[0003] In existing technologies, phase control methods often struggle to effectively address phase inconsistency issues caused by hardware differences. Specifically:

[0004] 1. Open-loop calibration method: The phase is adjusted only according to preset parameters, which cannot respond in real time to phase changes caused by hardware differences, resulting in reduced synthesis efficiency.

[0005] 2. Offline vector calibration method: Requires dedicated instruments (such as vector network analyzers) for offline measurement, cannot perform in-situ real-time calibration, and cannot cover changes in hardware characteristics after power-on.

[0006] 3. Synthetic Power Feedback Method: Phase consistency is inferred by detecting the synthesized power. However, due to the mismatch of the synthesized network, the feedback information is indirect and easily distorted, resulting in large calibration errors. Furthermore, the link needs to have a power combiner. This method is suitable for radar systems with power efficiency synthesis, but lacks effective phase calibration methods for space synthesis systems. Summary of the Invention

[0007] Based on the above analysis, the embodiments of the present invention aim to provide a multi-channel phase calibration method and system based on the detected target echo, so as to solve the problem in the prior art that the phase inconsistency caused by hardware differences (power amplifier, phase shifter, link asymmetry, etc.) of radar multi-channel cannot be solved online.

[0008] The objective of this invention is mainly achieved through the following technical solutions:

[0009] On one hand, embodiments of the present invention provide a multi-channel phase calibration method based on detected target echoes, comprising the following steps:

[0010] The radar system is triggered online to enter real-time phase calibration mode;

[0011] By using a time-division multiplexing mechanism, each transmission channel of the radar system is activated sequentially to radiate radar pulse signals to the target. The echo phase of each transmission channel is obtained by receiving the echo signals from the target.

[0012] Phase calibration inversion is performed based on the echo phase of each path to obtain the final compensated phase of each transmission channel, and then sent to the phase shifter of the corresponding transmission channel.

[0013] The system returns from calibration mode to normal operation mode, and the final compensated phase of each transmission channel is used as the initial phase of the corresponding channel for phase adjustment.

[0014] Furthermore, the echo phase of each transmission channel is obtained, including:

[0015] Set all transmit channel switches to the off state and reset the phase shifters of each transmit channel to zero;

[0016] Initiating the time-division transmission process: Turn on the switch of one transmission channel to transmit a radar pulse signal. The signal is radiated to detect the target after passing through the phase shifter of that transmission channel. Turn on the switch of the receiving channel to receive the echo signal and obtain the echo phase of that transmission channel. After receiving the echo signal of that transmission channel, turn off the switch of that transmission channel and automatically trigger the opening of the next transmission channel switch until the echo phases of all transmission channels are obtained.

[0017] Furthermore, the final compensated phase for each transmission channel includes:

[0018] Using the echo phase of any transmission channel as a reference, calculate the phase difference between the echo phase of other transmission channels and the reference, and obtain the initial compensation phase of the corresponding transmission channel.

[0019] The initial compensation phase is sent as the initial phase to the phase shifter of the corresponding transmission channel;

[0020] The time-division transmission process is initiated to perform phase calibration and inversion, obtaining the inversion echo phase of each transmission channel. If the inversion echo phase difference of each transmission channel is less than a preset threshold, the calibration is completed. Otherwise, the above process is iterated until the iteration exit condition is met, and the calibration is completed. The compensation phase at the time of calibration completion is the final compensation phase.

[0021] Furthermore, a maximum iteration time is preset, and a timeout timer is started during the phase calibration inversion. The iteration exit condition is that the timeout timer reaches the maximum iteration time.

[0022] Furthermore, the real-time phase calibration mode is triggered if any of the following conditions are met:

[0023] The real-time phase calibration mode is triggered the first time a target is detected after the radar is powered on.

[0024] If the target is detected again, and if the target is a fixed target, the change in the echo intensity of the target exceeds a preset first threshold; or if the target is a non-fixed target, the calibration factor corresponding to the target is less than a preset second threshold, then the real-time phase calibration mode is triggered.

[0025] Furthermore, the preset second threshold is determined through the following process:

[0026] Based on the target distance and echo power data during each radar detection process, the corresponding calibration factor is determined and stored.

[0027] The average value of the stored calibration factors is used as the preset second threshold;

[0028] If the calibration factor corresponding to a target detected in a certain instance is less than the second threshold, then the calibration factor for that instance is discarded, and the real-time phase calibration mode is triggered.

[0029] Furthermore, the calibration factor is determined based on the received power and the target detection distance in the radar equation.

[0030] Furthermore, the echo phase includes the initial phase of the radar pulse signal, the round-trip propagation phase of the electromagnetic wave, and the hardware phase offset of the transmission channel to be calibrated; wherein, the target distance is obtained by acquiring the time delay of the echo signal, and the round-trip propagation phase of the electromagnetic wave is obtained based on the target distance and the carrier wavelength.

[0031] On the other hand, embodiments of the present invention provide a multi-channel phase calibration system based on detected target echoes, comprising:

[0032] The dynamic recalibration trigger module is used to trigger the entry into real-time phase calibration mode online;

[0033] The calibration control unit is used to trigger the radar signal generating device to generate radar pulse signals, and to sequentially open each transmission channel of the radar transmitting system using a time-division transmission mechanism to radiate the radar pulse signals to the detection target. By receiving the echo signals from the detection target, the echo phase of each transmission channel is obtained; and the final compensated phase obtained by phase calibration inversion is sent to the phase shifter of the corresponding transmission channel, and the real-time calibration mode is exited.

[0034] The radar transmitting system is used to perform phase calibration inversion based on the echo phases of each channel to obtain the final compensated phase of each transmitting channel; it is also used to restore the normal operating mode by using the final compensated phase of each transmitting channel as the initial phase of the corresponding channel for phase adjustment.

[0035] Furthermore, the calibration control unit obtains the echo phase of each transmission channel, including:

[0036] The control switches all transmit channels to the off state, and the phase shifters of each transmit channel are reset to zero;

[0037] Initiating the time-division transmission process: Turn on the switch of one transmission channel to transmit a radar pulse signal. The signal is radiated to detect the target after passing through the phase shifter of that transmission channel. Turn on the switch of the receiving channel to receive the echo signal and obtain the echo phase of that transmission channel. After receiving the echo signal of that transmission channel, turn off the switch of that transmission channel and automatically trigger the opening of the next transmission channel switch until the echo phases of all transmission channels are obtained.

[0038] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0039] 1. This invention proposes a multi-channel phase calibration method based on the echo of a fixed target. It utilizes the radar's own transmit-receive link to directly invert the phase shift of the transmit channel through the echo signal of a target at a fixed distance, eliminates synthetic network interference, and achieves high-precision, high-real-time multi-channel dynamic phase calibration. It is compatible with radar pulse working mode and the calibration response time is ≤1s.

[0040] 2. This method eliminates the interference of inter-channel coupling on the echo signal through a time-division transmission strategy, shares a single receiving channel, avoids additional errors introduced by differences in receiver hardware, and is automatically performed when the radar is working. It does not require additional calibration equipment or modification of the radar's transmitting and receiving hardware architecture, making it simple to implement and environmentally adaptable.

[0041] 3. Different calibration triggering methods are set for different types of detection targets. In particular, for moving detection targets, the calibration factor is determined by combining the received power and detection range to identify calibration errors and trigger online calibration, thereby improving the accuracy of radar synthesis.

[0042] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0043] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0044] Figure 1This is a flowchart of a multi-channel phase calibration method based on the detected target echo, as described in an embodiment of the present invention.

[0045] Figure 2 This is a diagram of the architecture of a four-channel radar system for spatial power combining according to an embodiment of the present invention;

[0046] Figure 3 This is a logic diagram of phase calibration control according to an embodiment of the present invention. Detailed Implementation

[0047] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0048] Example 1

[0049] A specific embodiment of the present invention discloses a multi-channel phase calibration method based on the detected target echo, such as... Figure 1 As shown, it includes the following steps:

[0050] Step S1: The radar system is triggered online to enter the real-time phase calibration mode;

[0051] Step S2: Using a time-division transmission mechanism, sequentially activate each transmission channel of the radar system to radiate radar pulse signals to the target. By receiving the echo signals from the target, obtain the echo phase of each transmission channel.

[0052] Step S3: Perform phase calibration inversion based on the echo phase of each channel to obtain the final compensated phase of each transmission channel, and send it to the phase shifter of the corresponding transmission channel respectively;

[0053] Step S4: Restore from calibration mode to normal operation mode, and use the final compensated phase of each transmission channel as the initial phase of the corresponding channel for phase adjustment.

[0054] Using the above method, based on the radar's own transmit-receive link, the hardware phase offset of the transmit channel is directly extracted using the echo from a fixed target. Based on the phase offset, dynamic calibration and inversion are performed to obtain the final compensated phase. This method eliminates synthetic network interference and can perform calibration and compensation in real time while the radar is in operation, achieving high-precision online multi-channel phase calibration.

[0055] Existing phase control methods based on offline vector calibration rely on additional detection equipment such as vector network analyzers to perform calibration while the radar is offline. When the radar is operational and hardware undergoes dynamic changes, it cannot respond in real time. To address this issue, this invention proposes an online real-time calibration method based on the radar system's own transmit-receive link, specifically for space power combining radar systems.

[0056] Specifically, in step S1, the radar system is triggered to enter the real-time phase calibration mode online. After the system is operating normally, a calibration command is initiated and the system enters the real-time phase calibration mode when any of the following conditions are met, in order to compensate for dynamic phase shifts such as hardware phase thermal drift in real time:

[0057] 1) Timed calibration triggers the real-time calibration process after the radar detects a target for the first time after it is powered on.

[0058] 2) If the target is detected again, a threshold judgment is made based on the different detection targets. For fixed detection targets, the threshold is determined when the change in the echo intensity of the detection target exceeds the preset first threshold, or for non-fixed detection targets, the threshold is determined when the calibration factor corresponding to the detection target is less than the preset second threshold, so as to trigger real-time calibration.

[0059] It should be noted that the detection target during the calibration process can be either a fixed or non-fixed target. When the target is a fixed target, such as a corner reflector, a building with a known radar cross section (RCS), or a tower, the distance and echo power of the fixed target are recorded after the initial calibration. The echo intensity of the fixed target is then measured periodically. If the echo intensity drops beyond a preset first threshold (e.g., 0.5 dB, excluding environmental factors), calibration is triggered. When the target is a non-fixed target, a corresponding calibration factor is determined and stored based on the target distance and echo power data from each radar detection process. The average of the stored calibration factors is used as a preset second threshold. If the calibration factor for a target in a given detection is less than this preset second threshold, the calibration factor for that detection is discarded, and calibration is triggered. After calibration, the target is detected again, and the new calibration factor is stored as correct data.

[0060] Among them, according to the received power P in the radar equation r Based on the property that it is inversely proportional to the fourth power of the distance, we take the calibration factor j = Pr * R. 4 The radar equation is expressed as:

[0061]

[0062] Among them, P t For transmission power; G t G r λ represents the transmit / receive antenna gain; λ represents the wavelength; σ represents the target radar cross-section (RCS); and R represents the distance from the target to the radar.

[0063] It should be noted that a multi-channel radar system includes a radar signal generation and processing system, a power divider, an amplifier circuit, a digitally controlled phase shifter, and an antenna. The radar signal generation and processing system outputs radar pulse signals (e.g., 10GHz carrier frequency, 100μs pulse width, 1kHz repetition frequency) and processes the radar pulse signals received by the receiving antenna. The power divider divides the radar pulse signal output from the radar signal generation system into n equal-amplitude and equal-phase channels, and sends the divided signals to n independent transmission channels. Each transmission channel includes an amplification link, a digitally controlled phase shifter (referred to as a phase shifter), and a channel switch. The amplification link amplifies the divided signal, the phase shifter adjusts the phase (adjustment range is 0°~360°, adjustment step size is 0.5°), and the channel switch controls the channel's transmit / off state, connecting to the transmitting antenna array after passing through the switch. The antenna section includes a transmitting antenna array and a receiving antenna. The receiving antenna is connected to the radar signal generation and processing system via a receiving channel switch, and the received radar echo signal enters the radar signal generation and processing system for processing.

[0064] Specifically, in step S2, the radar system's transmission channels are sequentially activated using a time-division multiplexing mechanism, and the echo phase of each transmission channel is obtained, including:

[0065] S21. Set all transmit channel switches to the off state and clear the phase shifters of each transmit channel to zero;

[0066] S22. Start the time-division transmission process: Sequentially turn on one transmission channel at a time, while keeping the others off, to ensure that the signal of each channel is radiated independently and the echo is received, thus eliminating channel mutual coupling interference. Specifically, turn on the switch of one transmission channel to transmit a radar pulse signal. The signal is radiated to detect the target after passing through the phase shifter of that transmission channel. Turn on the switch of the receiving channel to receive the echo signal and obtain the echo phase of that transmission channel. After receiving the echo signal of that transmission channel, turn off the switch of that transmission channel and automatically trigger the opening of the next transmission channel switch until the echo phases of all transmission channels are obtained.

[0067] For example, such as Figure 2 As shown, taking a four-channel radar system as an example, the first channel switch is turned on, and the radar signal generation system generates a radar pulse signal. After passing through a 1-to-4 power divider, it is split into four channels. Each channel is amplified and phase-shifted before being radiated to the target. The receiving channel switch is turned on, and the echo signal acquisition is started (aligning with the echo arrival time). After being amplified by an LNA and down-converted by a mixer, the digital echo is acquired by the ADC of the radar signal processing system, and the echo phase θ1 (this echo phase is the phase difference relative to the transmitted pulse) is extracted. The first transmitting channel switch is turned off, which automatically triggers the opening of the next transmitting channel switch. The above operation is repeated for the second to fourth channels in sequence, and the echo phases θ2, θ3, and θ4 of the corresponding transmitting channels are acquired respectively.

[0068] Specifically, in step S3, after the acquisition of each echo phase is completed, the phase offset calculation process begins. Based on the obtained echo phases, phase calibration and inversion are performed, that is, the hardware phase offset of the transmission channel is inverted (eliminating the influence of propagation path phase). The specific process is as follows:

[0069] S31. Using the echo phase of any transmission channel as a reference, calculate the phase difference between the echo phase of other transmission channels and the reference, and obtain the initial compensation phase of the corresponding transmission channel.

[0070] For example, the i-th echo phase θ i The expression is:

[0071] θ i =θ0+Δφ i +θ_prop(i=1~4),

[0072] Where θ0 is the initial phase of the signal source (fixed value); θ_prop is the round-trip propagation phase of the electromagnetic wave; Δφ i Let t0 be the hardware phase offset (to be calibrated) of the i-th transmission channel. The one-way distance to the target is obtained from the time delay of the acquired echo signal, expressed as: t0 = 2R / c; where t0 is the time delay of the acquired echo signal, c is the speed of light, and R is the one-way distance to the target. Then, θ_prop can be obtained, expressed as θ_prop = 4πR / λ, where λ is the carrier wavelength. When θ_prop > 2π, the remainder is calculated by dividing θ_prop by 2π to ensure that the value of θ_prop is within the range of 0-2π.

[0073] Taking the first channel as the reference, i.e., the hardware phase offset Δφ1 is 0, calculate the phase amount that needs to be compensated for the remaining channels, i.e., the initial compensation phase, expressed as:

[0074] Second-path compensation: Δφ2 compensation = θ1 - θ2, to offset the difference between Δφ2 and Δφ1.

[0075] Third-path compensation amount: Δφ3 compensation = θ1 - θ3

[0076] Fourth-path compensation amount: Δφ4 compensation = θ1 - θ4.

[0077] S32. The initial compensation phase is sent as the initial phase to the phase shifter of the corresponding transmission channel;

[0078] S33. Start the time-division transmission process in step S22, perform phase calibration inversion, and obtain the inversion echo phase of each transmission channel; if the inversion echo phase difference of each transmission channel is less than the preset threshold, the calibration is completed; otherwise, iterate the above process until the iteration exit condition is met, then the calibration is completed.

[0079] For example, commands are sent to φ2~φ4 (i.e., the phase shifters of transmission channels 2, 3, and 4) to superimpose Δφ2 compensation to Δφ4 compensation respectively, that is, phase calibration inversion is performed using Δφ2 compensation to Δφ4 compensation as the initial phase (φ1 remains unchanged at 0°); step S22 is repeated, and the adjusted phase difference is calculated: |θ i '-θ j '|(i,j=1~4). If the phase difference of each echo is ≤1° (this phase difference threshold can be adjusted according to the specific accuracy requirements of the digital phase shifter), then the calibration is complete, and the compensation phase at the time of calibration completion is the final compensation phase; otherwise, iterative adjustment is performed until the accuracy is met. To prevent multiple iterations from failing to meet the accuracy requirements, a maximum iteration time is preset. During phase calibration inversion, a timeout function is activated. When the timeout reaches the maximum iteration time, the iteration process is terminated, and the echo phase with the smallest error is used as the final compensation phase.

[0080] It should be noted that, to facilitate the verification and testing of the phase calibration method of this invention, a metal reflector located at a known distance R (e.g., 10m) is used as a fixed detection target for calibration simulation testing to ensure the stability of the echo path. A calibration control unit is designed to deploy the phase control algorithm, such as... Figure 3 As shown, the phase shifter is adjusted based on phase offset calculation according to the time-division transmission echo acquisition, and the transmission and reception are repeatedly verified to perform dynamic recalibration.

[0081] Taking a 4-channel radar system as an example, the phase control algorithm triggers the initialization process by initiating a calibration command, including operation 1: the calibration control unit sets all four transmit channels to the "off" state (to avoid crosstalk between channels). Operation 2: the initial phase of the four phase shifters is uniformly set to 0° (reference phase).

[0082] After initialization, time-division transmission and echo acquisition are triggered, and the steps include:

[0083] Turn on the first channel switch and keep the other three channel switches off; the radar signal source emits a radar pulse (e.g., 10GHz, pulse width 100μs), which is amplified by the first power amplifier and phase-shifted by φ1 (initial 0°) before being radiated to the target through the antenna.

[0084] The receiving channel starts acquiring the echo signal (aligning with the echo arrival time), amplifies the echo signal through an LNA, downconverts it through a mixer, and then converts it into a digital signal by an ADC; the calibration control unit extracts the echo phase θ1 (the phase difference relative to the transmitted pulse) from the digital signal and stores it.

[0085] Turn off the switch of channel 1, repeat steps ① to ②, and turn on channels 2 to 4 in sequence to collect and store the echo phases θ2, θ3, and θ4 respectively.

[0086] Once θ1 through θ4 are acquired, phase offset calculation is triggered. The hardware phase offset of the transmission channel is retrieved based on the echo phase difference (eliminating the phase influence of the propagation path). The calculation process is as follows:

[0087] echo phase θ i The structure of (i = 1 to 4): θ i =θ0+Δφ i +θ_prop.

[0088] Using the first path as the reference (Δφ1 as reference 0), calculate the phase compensation required for the remaining paths:

[0089] Δφ2 compensation=θ1-θ2, Δφ3 compensation=θ1-θ3, Δφ4 compensation=θ1-θ4,

[0090] After the Δφ2 compensation to Δφ4 compensation calculation is completed, the phase shifter adjustment operation is triggered. That is, the calibration control unit sends instructions to the phase shifters φ2 to φ4 to superimpose Δφ2 compensation, Δφ3 compensation, and Δφ4 compensation respectively (φ1 remains unchanged at 0°).

[0091] Finally, repeat the transmit-receive verification, including:

[0092] Repeat the "time-division transmission and echo acquisition" operation to reacquire the adjusted echo phases θ1' to θ4'.

[0093] Calculate the adjusted phase difference; if all phase differences are ≤ preset thresholds (e.g., ≤ 1°), the calibration is complete and enters "normal working state"; if not, return to "phase offset calculation" to recalculate the compensation amount and adjust until the standard is met.

[0094] In this way, on the one hand, the dynamic calibration can adapt to the radar pulse working mode without modifying the radar transmitting and receiving hardware architecture, avoiding the tedious process of calibrating each channel with additional instruments; on the other hand, online calibration can respond to the dynamic changes of the hardware in real time to achieve high-precision real-time phase calibration.

[0095] Specifically, in step S4, after the calibration is completed or the calibration iteration process is predicted, the calibration mode is exited and the normal working mode is resumed. The final compensation phase of each transmission channel is used as the initial phase of the corresponding channel for subsequent phase adjustment. Based on the phase-calibrated echoes, the signals are synthesized. The synthesized echoes are used for subsequent ranging, velocity measurement, angle measurement, imaging and other processing.

[0096] Compared with existing technologies, this embodiment provides a multi-channel phase calibration method based on the echo of a detected target. Utilizing the radar's own transmit-receive link, it directly inverts the phase offset of the transmit channel by detecting the echo signal from the target at a distance. Based on this phase offset, dynamic calibration inversion is performed to obtain the final compensated phase. This ultimately achieves high-precision, high-real-time multi-channel dynamic phase calibration. On one hand, a time-division multiplexing transmission strategy eliminates interference from inter-channel coupling on the echo signal; on the other hand, it is performed automatically during radar operation, requiring no additional calibration equipment or modification of the radar transmit-receive hardware architecture, making it simple to implement and environmentally adaptable.

[0097] Example 2

[0098] Another specific embodiment of the present invention discloses a multi-channel phase calibration system based on the detection target echo, comprising:

[0099] The dynamic recalibration trigger module is used to trigger the entry into real-time phase calibration mode online;

[0100] The calibration control unit is used to trigger the radar signal generating device to generate radar pulse signals, and to sequentially open each transmission channel of the radar transmitting system using a time-division transmission mechanism to radiate the radar pulse signals to the detection target. By receiving the echo signals from the detection target, the echo phase of each transmission channel is obtained; and the final compensated phase obtained by phase calibration inversion is sent to the phase shifter of the corresponding transmission channel, and the real-time calibration mode is exited.

[0101] The radar transmitting system is used to perform phase calibration inversion based on the echo phases of each channel to obtain the final compensated phase of each transmitting channel; it is also used to restore the normal operating mode by using the final compensated phase of each transmitting channel as the initial phase of the corresponding channel for phase adjustment.

[0102] It should be noted that the calibration control unit is connected to the channel switches and phase shifters of the radar transmitting system to execute calibration logic (including control channel switching, phase calculation and adjustment, which can be reused with the control unit of the radar system itself to control the channel switches and phase shifters).

[0103] The system can perform online calibration of multi-channel phase according to any of the methods described in Embodiment 1. Related aspects can be referenced from each other, and are not repeated in this embodiment.

[0104] Compared with existing technologies, this embodiment provides a multi-channel phase calibration system based on the echo of the detected target. Through the coordinated operation of various modules, the system directly inverts the phase shift of the transmission channel using the echo signal of the detected target, eliminates synthetic network interference, and achieves high-precision multi-channel online phase calibration.

[0105] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0106] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-channel phase calibration method based on detected target echoes, characterized in that, Includes the following steps: The radar system is triggered online to enter real-time phase calibration mode; By using a time-division multiplexing mechanism, each transmission channel of the radar system is activated sequentially to radiate radar pulse signals to the target. The echo phase of each transmission channel is obtained by receiving the echo signals from the target. Phase calibration inversion is performed based on the echo phase of each path to obtain the final compensated phase of each transmission channel, and then sent to the phase shifter of the corresponding transmission channel. The system returns from calibration mode to normal operation mode, and the final compensated phase of each transmission channel is used as the initial phase of the corresponding channel for phase adjustment.

2. The method according to claim 1, characterized in that, The echo phase of each transmission channel is obtained, including: Set all transmit channel switches to the off state and reset the phase shifters of each transmit channel to zero; Initiating the time-division transmission process: Turn on the switch of one transmission channel to transmit a radar pulse signal. The signal is radiated to detect the target after passing through the phase shifter of that transmission channel. Turn on the switch of the receiving channel to receive the echo signal and obtain the echo phase of that transmission channel. After receiving the echo signal of that transmission channel, turn off the switch of that transmission channel and automatically trigger the opening of the next transmission channel switch until the echo phases of all transmission channels are obtained.

3. The method according to claim 2, characterized in that, The final compensated phase for each transmission channel includes: Using the echo phase of any transmission channel as a reference, calculate the phase difference between the echo phase of other transmission channels and the reference, and obtain the initial compensation phase of the corresponding transmission channel. The initial compensation phase is sent as the initial phase to the phase shifter of the corresponding transmission channel; The time-division transmission process is initiated to perform phase calibration and inversion, obtaining the inversion echo phase of each transmission channel; if the inversion echo phase difference of each transmission channel is less than a preset threshold, the calibration is completed; otherwise, the above process is iterated until the iteration exit condition is met, and the calibration is completed; wherein, the compensation phase at the time of calibration completion is the final compensation phase.

4. The method according to claim 3, characterized in that, A maximum iteration time is preset, and a timeout timer is started during the phase calibration and inversion. The iteration exit condition is that the timeout timer reaches the maximum iteration time.

5. The method according to any one of claims 1-4, characterized in that, The real-time phase calibration mode is triggered if any of the following conditions are met: The real-time phase calibration mode is triggered the first time a target is detected after the radar is powered on. If the target is detected again, and if the target is a fixed target, the change in the echo intensity of the target exceeds a preset first threshold; or if the target is a non-fixed target, the calibration factor corresponding to the target is less than a preset second threshold, then the real-time phase calibration mode is triggered.

6. The method according to claim 5, characterized in that, The preset second threshold is determined through the following process: Based on the target distance and echo power data during each radar detection process, the corresponding calibration factor is determined and stored. The average value of the stored calibration factors is used as the preset second threshold; If the calibration factor corresponding to a target detected in a certain instance is less than the second threshold, then the calibration factor for that instance is discarded, and the real-time phase calibration mode is triggered.

7. The method according to claim 6, characterized in that, The calibration factor is determined based on the received power and the target detection range in the radar equation.

8. The method according to claim 5, characterized in that, The echo phase includes the initial phase of the radar pulse signal, the round-trip propagation phase of the electromagnetic wave, and the hardware phase offset of the transmission channel to be calibrated; wherein, the target distance is obtained by the time delay of the acquired echo signal, and the round-trip propagation phase of the electromagnetic wave is obtained based on the target distance and the carrier wavelength.

9. A multi-channel phase calibration system based on the echo of a detected target, characterized in that, include: The dynamic recalibration trigger module is used to trigger the entry into real-time phase calibration mode online; The calibration control unit is used to trigger the radar signal generating device to generate radar pulse signals. It uses a time-division transmission mechanism to sequentially open each transmission channel of the radar transmission system, radiating the radar pulse signals to the target. By receiving the echo signals from the target, the echo phase of each transmission channel is obtained. The final compensated phase obtained from the phase calibration inversion is then sent to the phase shifters of the corresponding transmission channels, and the real-time calibration mode is exited. The radar transmitting system is used to perform phase calibration inversion based on the phase of each echo to obtain the final compensated phase of each transmitting channel; It is also used to restore normal operating mode, using the final compensated phase of each transmission channel as the initial phase of the corresponding channel for phase adjustment.

10. The system according to claim 9, characterized in that, The calibration control unit obtains the echo phase of each transmission channel, including: The control switches all transmit channels to the off state, and the phase shifters of each transmit channel are reset to zero; Initiating the time-division transmission process: Turn on the switch of one transmission channel to transmit a radar pulse signal. The signal is radiated to detect the target after passing through the phase shifter of that transmission channel. Turn on the switch of the receiving channel to receive the echo signal and obtain the echo phase of that transmission channel. After receiving the echo signal of that transmission channel, turn off the switch of that transmission channel and automatically trigger the opening of the next transmission channel switch until the echo phases of all transmission channels are obtained.

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