CN116232489A - Antenna array calibration method, antenna array calibration system and related equipment - Google Patents

Abstract

The application discloses an antenna array calibration method, an antenna array calibration system and related equipment, wherein the method comprises the following steps: obtaining calibration signals to be analyzed related to a plurality of target antennas in a target antenna array, and obtaining the amplitude-phase calibration data of the plurality of target antennas by utilizing the phase information of the calibration signals to be analyzed, wherein each target antenna corresponds to one calibration antenna respectively, and a preset position relationship exists between the target antenna with a corresponding relationship and the calibration antenna, namely, the amplitude-phase calibration of the target antenna can be realized by utilizing the calibration antenna meeting the preset position relationship, the calibration of the target antenna array is simplified, and the calibration efficiency of the antenna array is improved.

Description

Antenna array calibration method, antenna array calibration system and related equipment

Technical Field

The application relates to the technical field of antennas, in particular to an antenna array calibration method, an antenna array calibration system and related equipment.

Background

When entering public transportation places, the articles carried by pedestrians need to be detected, the metal articles on the pedestrians can be detected by means of the metal doors and the metal detectors, but the metal types are difficult to identify, the millimeter wave-based security inspection imaging system can image the pedestrians, and the images can be used for identifying the article types carried by the pedestrians.

The prior image imaging system comprises an antenna array, the antenna array needs to be calibrated before imaging, and the applicant of the application finds that another array with known accurate position information needs to be used in the prior calibration method in a long-term research and development process, and the position information has a great influence on calibration.

Disclosure of Invention

The technical problem that this application mainly solves is especially an antenna array calibration method, antenna array structure, equipment and medium, can simplify antenna array calibration method, reduces antenna array calibration's cost.

In order to solve the technical problems, one technical scheme adopted by the application is as follows: there is provided an antenna array calibration method, the method comprising: acquiring calibration signals to be analyzed related to a plurality of target antennas in a target antenna array, wherein the plurality of target antennas comprise at least one of target transmitting antennas and target receiving antennas, each target antenna corresponds to one calibration antenna in the calibration antenna array respectively, each target antenna has opposite transceiving properties with the corresponding calibration antenna and has a preset position relationship, and the calibration signals to be analyzed comprise amplitude and phase calibration signals transmitted between the plurality of target antennas and the calibration antennas and are received by the antennas serving as receiving sides in the plurality of target antennas and the calibration antennas; and acquiring the amplitude and phase calibration data of the plurality of target antennas by using the phase information of the calibration signals to be analyzed.

The target antennas are divided into a plurality of target antenna groups, different target antenna groups correspond to different calibration antennas, and all target antennas in the same target antenna group correspond to the same calibration antenna; and/or, the preset positional relationship includes a far-field positional relationship and a zero-degree positional relationship.

The target antennas are divided into a plurality of target antenna groups, one target antenna in the target antenna groups is a reference antenna corresponding to the target antenna groups, the target antennas except the reference antenna in the target antenna groups are other target antennas in the target antenna groups, one of all the reference antennas is a reference antenna, and the reference antennas except the reference antenna are other reference antennas; the obtaining of the amplitude and phase calibration data of the plurality of target antennas using the phase information of the calibration signal to be analyzed comprises: for each target antenna group, obtaining intra-group calibration data of other target antennas in the target antenna group relative to the reference antenna by utilizing a first phase difference between target amplitude calibration signals and reference amplitude calibration signals of other target antennas in the target antenna group, wherein the target amplitude calibration signals of the other target antennas are amplitude calibration signals transmitted between the other target antennas and calibration antennas corresponding to the other target antennas, and the reference amplitude calibration signals are amplitude calibration signals transmitted between the reference antennas and the calibration antennas corresponding to the reference antennas; for each other reference antenna, obtaining inter-group calibration data of the other reference antenna relative to the reference antenna by using a second phase difference between a first amplitude-phase calibration signal of the other reference antenna and a reference amplitude-phase calibration signal of the other reference antenna and a third phase difference between a second amplitude-phase calibration signal of the reference amplitude-phase calibration signal and the other reference antenna, wherein the first amplitude-phase calibration signal of the other reference antenna is an amplitude-phase calibration signal transmitted between the reference antenna and a calibration antenna corresponding to the other reference antenna, and the reference amplitude-phase calibration signal is an amplitude-phase calibration signal transmitted between the reference antenna and a calibration antenna corresponding to the reference antenna; and obtaining the amplitude and phase calibration data of the plurality of target antennas based on the inter-group calibration data and the intra-group calibration data.

The method for obtaining the intra-group calibration data of other target antennas in the target antenna group relative to the reference antenna by using the first phase difference between the target amplitude calibration signal and the reference amplitude calibration signal of the other target antennas in the target antenna group comprises the following steps: performing spectrum analysis on the amplitude and phase calibration signal received by the first receiving side antenna to obtain first phase information of a target amplitude and phase calibration signal and second phase information of a reference amplitude and phase calibration signal, wherein the first receiving side antenna is an antenna serving as a receiving side in a target antenna group and a corresponding calibration antenna; determining phase differences between other target antennas and the reference antenna as intra-group calibration data based on a first phase difference between the first phase information and the second phase information; obtaining inter-group calibration data of the other reference antenna relative to the reference antenna using a second phase difference between the first amplitude phase calibration signal of the other reference antenna and the reference amplitude phase calibration signal of the other reference antenna and a third phase difference between the reference amplitude phase calibration signal and the second amplitude phase calibration signal of the other reference antenna, comprising: performing spectrum analysis on the amplitude-phase calibration signal received by the second receiving side antenna to obtain second phase information of a reference amplitude-phase calibration signal, third phase information of the first amplitude-phase calibration signal, fourth phase information of a reference amplitude-phase calibration signal and fifth phase information of the second amplitude-phase calibration signal, wherein the second receiving side antenna is a reference antenna, each other reference antenna, a calibration antenna corresponding to the reference antenna and a calibration antenna corresponding to the other reference antennas, and the second receiving side antenna is an antenna serving as a receiving side; the phase differences between the other reference antennas and the reference antenna are determined as inter-group calibration data based on the second phase difference between the second phase information and the third phase information, and the third phase difference between the fourth phase information and the fifth phase information.

Wherein the method further comprises: and controlling each transmitting side antenna to transmit signals by taking the antenna serving as the transmitting side in the plurality of target antennas and the calibration antenna as the transmitting side antenna.

Wherein the transmitted signals include an amplitude-phase calibration signal, and controlling each transmitting-side antenna to transmit signals, comprising: according to the rule of the additional phase values, respectively determining different additional phase sequences for each transmitting side antenna, wherein the additional phase sequences comprise a preset number of additional phase values; and respectively transmitting a preset number of pulse signals as amplitude and phase calibration signals by utilizing each transmitting side antenna, and respectively carrying out phase addition on the preset number of pulse signals according to additional phase values contained in the additional phase sequence.

Wherein, for a plurality of preset frequency points, the method is executed once under each preset frequency point: and controlling each transmitting side antenna to transmit the amplitude-phase calibration signal corresponding to the preset frequency point, acquiring the calibration signal to be analyzed under the preset frequency point, and acquiring the amplitude-phase calibration data under the preset frequency point by utilizing the phase information of the calibration signal to be analyzed.

Wherein the plurality of target antennas includes at least one target transmit antenna and at least one target receive antenna, the method further comprising: acquiring a coupling calibration signal received by a target receiving antenna in a darkroom environment, wherein the coupling calibration signal is transmitted by a target transmitting antenna in the darkroom environment; and obtaining coupling compensation data of the target antenna array according to the coupling calibration signal received by the target receiving antenna.

Wherein the plurality of target antennas includes at least one target transmit antenna and at least one target receive antenna, the method further comprising: the method comprises the steps of obtaining detection echo data by using detection echo signals received by all target receiving antennas, wherein the detection echo signals are echo signals of detection signals transmitted by all target transmitting antennas in a time-sharing manner; calibrating the detection echo data by using detection calibration data to obtain data to be imaged, wherein the detection calibration data comprises amplitude calibration data; imaging is carried out by utilizing the data to be imaged, and a detection image is obtained.

Wherein the detection calibration data further comprises real-time calibration data; the target antenna array comprises at least one group of reference networks, the reference networks comprise a reference transmitting antenna, a reference receiving antenna and an attenuation network connected between the reference transmitting antenna and the reference receiving antenna, the reference transmitting antenna and the reference receiving antenna belong to the same area in the target antenna array, and before the detection calibration data are used for calibrating the detection echo data to obtain the data to be imaged, the method further comprises: and obtaining real-time calibration data about the target antenna array by utilizing reference echo signals received by reference receiving antennas in at least one group of reference networks, wherein the reference echo signals are echo signals of reference signals transmitted by reference transmitting antennas.

Wherein obtaining real-time calibration data for the target antenna array using the reference echo signals received by the reference receive antennas in the at least one set of reference networks comprises: carrying out phase solution on the reference echo signals received by the reference receiving antennas for each reference network to obtain sixth phase information of the reference echo signals received by the reference receiving antennas in the reference network; and obtaining real-time calibration data about the target antenna array based on the sixth phase information and seventh phase information corresponding to the attenuation network, wherein the real-time calibration data is used for calibrating inherent errors of the target antenna array in the current detection process.

Before the calibration of the detection echo data by the detection calibration data to obtain the data to be imaged, the method further comprises: and preprocessing the detected echo data, wherein the preprocessing comprises filtering processing and/or weight adjustment, and the weight adjustment is used for setting corresponding weights for target receiving antennas at different positions.

Imaging by using the data to be imaged, and obtaining the detection image comprises the following steps: gridding the imaging region; calculating an occupation state and a scattering coefficient of each grid in an imaging area based on data to be imaged; a detection image is obtained from the occupancy state and the scattering coefficient of each grid in the imaging region.

The detection signals comprise detection signals corresponding to a plurality of preset frequency points respectively; and/or, detecting the calibration data further comprises coupling compensation data.

In order to solve the technical problems, one technical scheme adopted by the application is as follows: there is provided an antenna calibration system including an antenna array structure and a calibration device, wherein the calibration device is configured to perform the antenna array calibration method in any one of the foregoing to calibrate a plurality of target antennas in the antenna array structure, the antenna array structure being disposed on a plane, the antenna array structure including: the antenna system comprises a plurality of receiving antenna groups and a plurality of transmitting antenna groups, wherein the plurality of receiving antenna groups are arranged at intervals along a first direction by a first distance, the receiving antenna groups comprise a plurality of receiving antennas arranged along a second direction, and the intervals of adjacent receiving antenna pairs close to two ends of the receiving antenna groups are smaller than the intervals of adjacent receiving antenna pairs far from two ends of the receiving antenna groups; the plurality of transmitting antenna groups are arranged between at least one group of receiving antenna group pairs, two receiving antenna groups contained in different receiving antenna group pairs are different, the number of the transmitting antenna groups between each group of receiving antenna group pairs is at least two, the transmitting antenna groups are arranged along a second direction at intervals by a second distance, each transmitting antenna group comprises a plurality of transmitting antennas which are arranged along the first direction at intervals, and the second distance is larger than the interval between adjacent receiving antenna pairs in the receiving antenna groups.

The number of the receiving antenna group pairs is at least two, the plurality of the transmitting antenna groups are divided into a plurality of antenna groups, each antenna group comprises one transmitting antenna group among the receiving antenna group pairs, and the transmitting antenna groups contained in each antenna group are arranged along a first direction;

the interval between adjacent receiving antenna pairs in the receiving antenna group is positively correlated with the distance between the adjacent receiving antenna pairs and the two ends of the receiving antenna group.

The plurality of transmitting antenna groups are divided into a plurality of antenna groups, each antenna group comprises one transmitting antenna group between each receiving antenna group pair, and the distance between the adjacent transmitting antenna groups in the antenna groups is 4mm.

Wherein the first distance is 136mm.

Wherein the second distance is 136mm.

Wherein the spacing between adjacent pairs of receiving antennas in the group of receiving antennas is greater than 2mm.

In order to solve the technical problems, another technical scheme adopted by the application is as follows: an antenna array is provided, which is an antenna array structure included in any one of the antenna calibration systems described above.

In order to solve the technical problems, another technical scheme adopted by the application is as follows: there is provided a calibration apparatus comprising a memory and a processor coupled to each other, the processor being operable to execute program instructions stored in the memory to implement the antenna array calibration method of any one of the above.

In order to solve the technical problems, another technical scheme adopted by the application is as follows: there is provided a computer readable storage medium having stored thereon program instructions which when executed by a processor implement the antenna array calibration method of any of the above.

According to the scheme, the calibration signals to be analyzed related to the plurality of target antennas in the target antenna array are obtained, the phase information of the calibration signals to be analyzed is utilized to obtain the amplitude and phase calibration data of the plurality of target antennas, each target antenna corresponds to one calibration antenna respectively, a preset position relationship exists between the target antenna with a corresponding relationship and the calibration antenna, namely, the amplitude and phase calibration of the target antenna can be realized by utilizing the calibration antenna meeting the preset position relationship, the calibration of the target antenna array is simplified, and the calibration efficiency of the antenna array is improved.

Drawings

FIG. 1 is a flow chart of an embodiment of an antenna array calibration method of the present application;

FIG. 2 is a flow chart of another embodiment of step S120 of the present application;

FIG. 3 is a schematic diagram of one embodiment of an amplitude phase calibration signal spectrum of the present application;

FIG. 4 is a schematic diagram of one embodiment of a target antenna array and a calibration antenna array of the present application;

FIG. 5 is a flow chart of another embodiment of the antenna array calibration method of the present application;

FIG. 6 is a flow chart of another embodiment of the antenna array calibration method of the present application;

FIG. 7 is a schematic diagram of one embodiment of a detected image of the present application;

FIG. 8 is a schematic diagram of a frame of an embodiment of an antenna array of the present application;

FIG. 9 is a schematic diagram of a frame of one embodiment of an antenna calibration system of the present application;

FIG. 10 is a schematic diagram of a framework of an embodiment of the calibration apparatus of the present application;

FIG. 11 is a schematic diagram of a framework of one embodiment of the computer-readable storage medium of the present application.

Detailed Description

In order to make the objects, technical solutions and effects of the present application clearer and more specific, the present application will be further described in detail below with reference to the accompanying drawings and examples. In the following description, for purposes of explanation and not limitation, specific details are set forth such as the particular system architecture, interfaces, techniques, etc., in order to provide a thorough understanding of the present application.

The term "and/or" is herein merely an association relationship describing an associated object, meaning that there may be three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship. Further, "a plurality" herein means two or more than two. In addition, the term "at least one" herein means any one of a plurality or any combination of at least two of a plurality, for example, including at least one of A, B, C, and may mean including any one or more elements selected from the group consisting of A, B and C.

It should be noted that the antenna array calibration method in the present application may be performed by a calibration device, which may be any device having processing capability, for example, a mobile phone, a computer, a tablet computer, etc.

Referring to fig. 1, fig. 1 is a flow chart illustrating an embodiment of an antenna array calibration method according to the present application. The antenna array calibration method is used for calibrating the target antenna array. Specifically, the method may comprise the steps of:

step S110: calibration signals to be analyzed, which are related to a plurality of target antennas in a target antenna array, are acquired.

From the transceiving nature, the antennas in the target antenna array include two types: a transmit antenna and a receive antenna. Wherein the plurality of target antennas includes at least one of a target transmitting antenna and a target receiving antenna. Step S110 and step S120 may be used to perform an amplitude phase calibration of the antennas in the target antenna array.

The plurality of target antennas may include all or part of the antennas in the target antenna array, e.g., the plurality of target antennas include all of the receive antennas in the target antenna array, or the plurality of target antennas include part of the transmit antennas and part of the receive antennas in the target antenna array, and so on.

If the plurality of target antennas include the target transmitting antenna and the target receiving antenna at the same time, the calibration of the amplitude and phase of the target transmitting antenna and the calibration of the amplitude and phase of the target receiving antenna in the plurality of target antennas may be performed independently, and obtaining the calibration signal to be analyzed related to the plurality of target antennas may include obtaining a corresponding calibration signal to be analyzed for the target transmitting antenna in the plurality of target antennas and obtaining a corresponding calibration signal to be analyzed for the target receiving antenna in the plurality of target antennas.

Each target antenna corresponds to one calibration antenna in the calibration antenna array, and each target antenna has opposite transceiving properties with the corresponding calibration antenna and has a preset position relationship. The calibration antenna corresponding to the target receiving antenna is a transmitting antenna, and the calibration antenna corresponding to the target transmitting antenna is a receiving antenna. For example, the plurality of target antennas includes target transmit antennas, each corresponding to one of the receive antennas in the calibration antenna array. The target antenna with the corresponding relation and the calibration antenna have a preset position relation.

The calibration signal to be analyzed comprises amplitude calibration signals transmitted between the target antennas and the calibration antennas, and the amplitude calibration signals are received by the antennas serving as receiving sides in the target antennas and the calibration antennas.

In a specific application scenario, the plurality of target antennas include a target transmitting antenna, the calibration signal to be analyzed about the target transmitting antenna includes an amplitude calibration signal transmitted between the target transmitting antenna and the calibration antenna (receiving antenna), and the amplitude calibration signal is received by the calibration antenna.

In some embodiments, each target antenna corresponds to a different calibration antenna, or in some embodiments, the plurality of target antennas is divided into a plurality of target antenna groups, different target antenna groups correspond to different calibration antennas, and each target antenna in each target antenna group corresponds to the same calibration antenna.

Step S120: and acquiring the amplitude and phase calibration data of the plurality of target antennas by using the phase information of the calibration signals to be analyzed.

If the plurality of target antennas include a target transmitting antenna and a target receiving antenna, the target transmitting antenna and the target receiving antenna may also be processed separately, for example, the target transmitting antenna may acquire the amplitude calibration data of the target transmitting antenna by using the phase information of the amplitude calibration signal transmitted between the target transmitting antenna and the corresponding calibration antenna (receiving antenna). For the target receiving antenna, the phase information of the amplitude and phase calibration signal transmitted between the target receiving antenna and the corresponding calibration antenna (transmitting antenna) is utilized to acquire the amplitude and phase calibration data of the target receiving antenna.

The target antenna array may be used for detecting objects to be detected, for example for security checks in public places etc. For example, the target antenna array is used for sending out a detection signal and receiving a detection echo signal so as to image the object to be detected to obtain a detection image, and the detection image can be used for a user to judge whether the object to be detected contains forbidden objects. The purpose of the amplitude phase calibration is to eliminate the amplitude phase differences between all target receiving antennas in the target antenna array and between all target transmitting antennas. Thereby avoiding that the difference between the target receiving antennas/the difference between the target transmitting antennas affects the detection imaging in the detection process by using the target antenna array.

In order to calibrate the plurality of target antennas, the phase information of the calibration signal to be analyzed, which is transmitted between the plurality of target antennas and the calibration antenna, can reflect the respective phase information of the plurality of target antennas, and amplitude and phase calibration data of the plurality of target antennas can be obtained based on the phase information of the calibration signal to be analyzed, and the amplitude and phase calibration data can be used for adjusting the phases of the plurality of target antennas to be consistent, i.e. can be used for realizing amplitude and phase calibration.

According to the scheme, the calibration signals to be analyzed related to the plurality of target antennas in the target antenna array are obtained, and the phase information of the calibration signals to be analyzed is utilized to obtain the amplitude and phase calibration data of the plurality of target antennas, wherein each target antenna corresponds to one calibration antenna respectively, and a preset position relationship exists between the target antenna with the corresponding relationship and the calibration antenna. The calibration antenna and the target antenna meet the preset position relation, and the phase information of the calibration signal to be analyzed is utilized, so that the specific position information between the calibration antenna and the target antenna is not needed, the amplitude and phase calibration data can be obtained, the calibration of the target antenna array is simplified, and the calibration efficiency of the antenna array is improved.

Referring to fig. 2, fig. 2 is a flowchart illustrating another embodiment of step S120 of the present application.

It should be noted that, the plurality of target antennas in the target antenna array may be divided into a plurality of target antenna groups, different target antenna groups correspond to different calibration antennas, and each target antenna in the same target antenna group corresponds to the same calibration antenna. And a preset position relation exists between each target antenna in the same target antenna group and the corresponding calibration antenna.

In some embodiments, the preset positional relationship includes a far field positional relationship and a zero degree positional relationship.

The echo of one party with a preset position relationship can be regarded as a parallel wave for the other party, the assumption is only satisfied when the vertical distance D >2 x D/lambda between the two is equal to the size of the same target antenna group, lambda is the wavelength of the transmitting carrier wave, and the two can be considered as meeting the far-field condition. The zero-degree position relation in the preset position relation refers to that under the far field condition, the projection of the calibration antenna corresponding to the same target antenna group along the vertical direction of the calibration antenna and the calibration antenna can fall in the area of the same target antenna group.

Further, one target antenna in the target antenna group is a reference antenna corresponding to the target antenna group, and the target antennas except the reference antenna in the target antenna group are other target antennas in the target antenna group. The reference antenna may be used as a calibration reference for other target antennas in the target antenna group. One of all the reference antennas is a reference antenna, and the reference antennas other than the reference antenna are other reference antennas. The reference antenna may be used as a calibration reference for all target antennas, specifically, after the intra-group calibration is completed by using the reference antennas of each group, the target antennas in the target antenna group may be considered as having completed the calibration with the reference antennas of the group, and then the inter-group calibration is performed by using the reference antenna as a calibration reference for other reference antennas, so as to realize that all target antennas are calibrated by using the reference antenna as a calibration reference.

The calibration device in the present application can control the target antenna array and the antenna of the calibration antenna array, for example, control the target transmitting antenna to transmit signals, and the like. Specifically, step S120 may include the steps of:

step S221: and obtaining intra-group calibration data of other target antennas in the target antenna group relative to the reference antenna by using the first phase difference between the target amplitude-phase calibration signals and the reference amplitude-phase calibration signals of the other target antennas in the target antenna group.

The target amplitude calibration signal refers to an amplitude calibration signal transmitted between the target antenna and a calibration antenna corresponding to the target antenna, and the reference amplitude calibration signal refers to an amplitude calibration signal transmitted between the reference antenna and a calibration antenna corresponding to the reference antenna.

One target antenna group corresponds to the same calibration antenna, the phase information of the target amplitude and phase calibration signals of other target antennas in the group can reflect the phase information of other target antennas, and the phase information of the reference amplitude and phase calibration signals can reflect the phase information of the reference antennas in the group. Therefore, the first phase difference between the target amplitude-phase calibration signal and the reference amplitude-phase calibration signal of the other target antennas can reflect the phase difference between the other target antennas and the reference antenna, and the intra-group calibration data of the other target antennas in the target antenna group relative to the reference antenna can be obtained. The intra-set calibration data may be used to calibrate other target antennas within the target antenna set with reference antennas as calibration references.

The calibration device may control each of the plurality of target antennas and the calibration antenna to transmit signals, wherein the transmitted signals may include an amplitude calibration signal. In performing the one-time amplitude calibration, the calibration device may control all transmitting side antennas to transmit the amplitude calibration signal simultaneously, or may control all transmitting side antennas to transmit the amplitude calibration signal within a certain shorter time interval, which may be considered equivalent to simultaneous transmission. The simultaneous transmission is realized under ideal conditions, and in practical application scenarios, there may be a signal transmission sequence between all the transmitting antennas, and controlling all the transmitting antennas to transmit in a shorter time interval may be considered as equivalent to simultaneous transmission.

In a specific application scenario, the multiple target antennas include target transmitting antennas, and the calibration device may control all the target transmitting antennas to transmit the amplitude-phase calibration signal simultaneously.

In a specific application scenario, the multiple target antennas include target receiving antennas, and the calibration device may control all the calibration antennas (transmitting antennas) to transmit the amplitude-phase calibration signal simultaneously.

In a specific application scenario, the plurality of target antennas include a target receiving antenna and a target transmitting antenna, and the target receiving antenna and the target transmitting antenna can be respectively and independently transmitted with an amplitude-phase calibration signal. For a target receiving antenna, all calibration antennas (transmitting antennas) transmit an amplitude-phase calibration signal at the same time; for the target transmitting antennas, all the target transmitting antennas transmit the amplitude and phase calibration signals at the same time.

Taking a target antenna as an emitting antenna for illustration, a group of target antennas comprises 6 target emitting antennas, which are sequentially target emitting antennas 1-6, the target antenna group corresponds to the same calibration antenna, wherein the target emitting antenna 1 is a reference antenna, for the target emitting antenna 2, a target amplitude-phase calibration signal is transmitted between the target emitting antenna 2 and the corresponding calibration antenna, a reference calibration signal is transmitted between the target emitting antenna 1 (reference antenna) and the corresponding calibration antenna, and the intra-group calibration data of the target emitting antenna 2 can be determined by utilizing the first phase difference between the target amplitude-phase calibration signal and the reference calibration signal of the target emitting antenna 2. The intra-set calibration data is used for amplitude-phase calibration of the target transmit antenna 2 with the target transmit antenna 1 (reference antenna) as a calibration reference. The same applies to the target transmit antennas 3-6. In the above example, when all the transmitting antennas (including the target transmitting antennas 1 and 2) transmit simultaneously and there is a preset positional relationship between the target transmitting antenna and the calibration antenna having a corresponding relationship, the target amplitude-phase calibration signal and the reference calibration signal are received by the same calibration antenna for the target transmitting antenna 1 (reference antenna) and the target transmitting antenna 2. The first phase difference between the phase information of the target amplitude and phase calibration signal and the phase information of the reference calibration signal can reflect the difference between the phase information of the target transmitting antenna 2 and the phase information of the reference antenna, so that the intra-group calibration data can be obtained according to the first phase difference, and the intra-group calibration data can be used for amplitude and phase calibrating the target transmitting antenna 2 by taking the reference antenna as a calibration reference.

Similarly, when the target antenna is a receiving antenna, a group of target antennas includes 10 target receiving antennas, which are sequentially target receiving antennas 1 to 10, and the target antenna groups correspond to the same calibration antennas, where the target receiving antenna 1 is a reference antenna, for the target receiving antenna 2, a target amplitude-phase calibration signal is transmitted between the target receiving antenna 2 and the corresponding calibration antenna, a reference calibration signal is transmitted between the target receiving antenna 1 (reference antenna) and the corresponding calibration antenna, and the intra-group calibration data of the target receiving antenna 2 can be determined by using a first phase difference between the target amplitude-phase calibration signal and the reference calibration signal of the target receiving antenna 2. The intra-set calibration data is used for performing an amplitude-phase calibration of the target receiving antenna 2 with respect to the target receiving antenna 1 (reference antenna) as a calibration reference. The same applies to the target receiving antennas 3-10. In the above description, the target receiving antennas in the target antenna group receive the signals sent by the same calibration antenna, and when there is a preset positional relationship between the target receiving antennas and the calibration antennas, the first phase difference between the phase information of the target amplitude calibration signal and the phase information of the reference calibration signal can reflect the phase difference between the phase information of the target receiving antenna 2 and the phase information of the reference antenna, so that the intra-group calibration data can be obtained according to the first phase difference, and the intra-group calibration data can be used for performing amplitude-phase calibration on the target receiving antenna 2 by using the reference antenna as a calibration reference.

Step S221 is performed for each target antenna group to achieve intra-group amplitude phase calibration for all target antenna groups.

Step S222: and obtaining inter-group calibration data of the other reference antennas relative to the reference antenna by using a second phase difference between the first amplitude-phase calibration signal of the other reference antennas and the reference amplitude-phase calibration signal of the other reference antennas and a third phase difference between the reference amplitude-phase calibration signal and the second amplitude-phase calibration signal of the other reference antennas.

The reference amplitude calibration signal is an amplitude calibration signal transmitted between the reference antenna and a calibration antenna corresponding to the reference antenna, and the reference amplitude calibration signal is an amplitude calibration signal transmitted between the reference antenna and a calibration antenna corresponding to the reference antenna. The first amplitude calibration signals of the other reference antennas are amplitude calibration signals transmitted between the reference antenna and the calibration antennas corresponding to the other reference antennas, and the second amplitude calibration signals of the other reference antennas are amplitude calibration signals transmitted between the other reference antennas and the calibration antennas corresponding to the reference antennas.

It will be appreciated that during a single calibration of the amplitude and phase, the calibration device may control all the transmit antennas to transmit the amplitude and phase calibration signal simultaneously.

Taking the target antennas as an example, the target antennas include 18 target transmitting antennas (denoted as Tx1-Tx 18), the target transmitting antennas are divided into 3 target antenna groups according to the sequence, and the calibration antennas 1-3 (denoted as Rx1-Rx 3) are respectively corresponding to the target transmitting antennas, and the plurality of target transmitting antennas are subjected to the amplitude phase calibration, so that all the target transmitting antennas 1-18 transmit the amplitude phase calibration signals at the same time, and the calibration antennas 1-3 receive the amplitude phase calibration signals. Tx1-Tx6 is used as a target antenna group, tx1 is a reference antenna, and Tx7 and Tx13 are respectively used as reference antennas of Tx7-Tx12 and Tx13-Tx 18. Step S221 is executed to obtain intra-group calibration data of the target antenna group using Tx1 as a calibration reference, obtain intra-group calibration data of the target antenna group using Tx8-Tx12 as a calibration reference, and obtain intra-group calibration data of the target antenna group using Tx13 as a calibration reference, and Tx14-Tx 18. Then, step S222 is performed to obtain inter-group calibration data by taking Tx7 and Tx13 as calibration references with Tx 1.

It should be noted that, the phase information of the two phase calibration signals may be obtained by spectral analysis, and the difference between the two phase calibration signals may be obtained by comparing the respective phase information of the two phase calibration signals.

Step S221 may be implemented by: and performing frequency spectrum analysis on the amplitude and phase calibration signals received by the first receiving side antenna to obtain first phase information of the target amplitude and phase calibration signals and second phase information of the reference amplitude and phase calibration signals, and determining phase differences between other target antennas and the reference antennas according to first phase differences between the first phase information and the second phase information to serve as intra-group calibration data. The first receiving side antenna is an antenna serving as a receiving side in the target antenna group and the corresponding calibration antenna.

Step S222 may be implemented by: and carrying out frequency spectrum analysis on the amplitude-phase calibration signal received by the second receiving side antenna to obtain second phase information of the reference amplitude-phase calibration signal, third phase information of the first amplitude-phase calibration signal, fourth phase information of the reference amplitude-phase calibration signal and fifth phase information of the second amplitude-phase calibration signal, and determining phase differences between other reference antennas and the reference antenna as inter-group calibration data based on second phase differences between the second phase information and the third phase information and third phase differences between the fourth phase information and the fifth phase information.

In the above scheme, the calibration antenna and the target antenna satisfy a preset position relationship, and phase information of the amplitude calibration signal is utilized when the amplitude calibration data is acquired, without using specific position information of the calibration antenna and the target antenna (the specific position information is used for representing a phase change condition of signal transmission between the calibration antenna and the target antenna). And further, all transmitting side antennas transmit simultaneously when the amplitude and phase calibration is performed in the scheme. The method meets the requirement that the accuracy requirement of the preset position relation on the setting position of the calibration antenna is lower than the accuracy requirement on the specific position information when the specific position information is used for calculation, simplifies the step of calibrating the target antenna, and improves the calibration efficiency. The influence caused by inaccurate array antenna position information is effectively avoided, the influence of deviation of specific position relation on the amplitude and phase calibration data is reduced, and the accuracy of the amplitude and phase calibration data can be improved.

Referring to fig. 3, fig. 3 is a schematic diagram illustrating an embodiment of an amplitude-phase calibration signal spectrum according to the present application.

In this embodiment, the target transmitting antennas are 18 (denoted as Tx1-Tx 18), and are divided into 3 target antenna groups in sequence, corresponding to the calibration antennas 1-3 (denoted as Rx1-Rx 3), respectively. The amplitude calibration is performed for a plurality of target transmitting antennas at the same time, so that all target transmitting antennas 1-18 transmit the amplitude calibration signal at the same time, and the calibration antennas 1-3 receive the amplitude calibration signal. Tx1-Tx6 is used as a target antenna group, tx1 is a reference antenna, and Tx7 and Tx13 are respectively used as reference antennas of Tx7-Tx12 and Tx13-Tx 18.

For Tx1-Tx6, the depth distance of Rx1 to Tx1-Tx6 is much greater than 2D ² And (3) lamba, wherein D is the transverse distance of Tx1-Tx6, lamba is the carrier wavelength, namely, the far-field position relationship between Tx1-Tx6 and Rx1 can be considered, meanwhile, rx1 is positioned at the zero-degree position of Tx1-Tx6, and the phase deviation of Tx2-Tx6 relative to Tx1 is obtained by combining digital beam forming.

In the figure, (a) is a spectrum diagram of an amplitude calibration signal received by Rx1, (b) is a spectrum diagram of an amplitude calibration signal received by Rx2, and (c) is a spectrum diagram of an amplitude calibration signal received by Rx3, and the abscissa of the spectrum diagram represents frequency. The amplitude and phase calibration signals respectively transmitted by Tx1-Tx18 can be received for each calibration antenna, and the amplitude and phase calibration signals transmitted by each target transmit antenna have different phase information. For example, from the first phase information of the target phase calibration signals of Tx2 and Rx1 and the second phase information of the reference phase calibration signals between Tx1 and Rx1, intra-group calibration data about Tx2 can be obtained, and the same applies to Tx3-Tx 6. In addition, similar processing is performed on Tx7-Tx12, tx13-Tx18 to enable corresponding intra-group calibration data.

Taking as an example the inter-group calibration between Tx1 and Tx7, the phase of the amplitude and phase calibration signal satisfies the following relationship:

φTiRj＝φTi+φRj+φTiRj_delay

φT1R1＝φT1+φR1+φT1R1_delay

φT1R2＝φT1+φR2+φT1R2_delay

φT7R1＝φT7+φR1+φT7R1_delay

φT7R2＝φT7+φR2+φT7R2_delay

Where ΦTiRj represents the phase of the amplitude and phase calibration signal transmitted between the transmit antenna i and the receive antenna j, ΦTi represents the phase of the transmit antenna i, ΦRj represents the phase of the receive antenna j, ΦTiRj_delay represents the phase of the transmit antenna i and the receive antenna j due to distance.

From the above relation, it can be seen that:

/>

tx1 is a reference antenna, and a reference amplitude calibration signal is transmitted between Tx1 and its corresponding calibration antenna Rx1, and fourth phase information of the reference amplitude calibration signal may be denoted as Φt1r1.Tx7 is another reference antenna, and a reference amplitude calibration signal is transmitted between Tx7 and its corresponding calibration antenna Rx2, and the second phase information of the reference amplitude calibration signal may be denoted as phit7r2. The third phase information of the first amplitude phase calibration signal may be denoted as phit 1R2 and the fifth phase information of the second amplitude phase calibration signal may be denoted as phit 7R1.

The phase difference between the other reference antenna Tx7 and the reference antenna Tx1 is determined as the inter-group calibration data based on the second phase difference between the second phase information Φt7r2 and the third phase information Φt1r2, the third phase difference between the fourth phase information Φt1r1 and the fifth phase information Φt7r1.

The phase differences between all other reference antennas and the reference antenna can be obtained by the same method, so as to obtain the inter-group calibration data. In addition, if the target antenna is a target receiving antenna, inter-group calibration data can be determined similarly.

Further, controlling each transmitting-side antenna to transmit a signal includes: according to the rule of the additional phase values, different additional phase sequences are respectively determined for each transmitting side antenna, and each transmitting side antenna is utilized to respectively transmit a preset number of pulse signals as amplitude-phase calibration signals, wherein the additional phase sequences comprise a preset number of additional phase values, and the preset number of pulse signals are respectively subjected to phase addition according to the additional phase values contained in the additional phase sequences.

It should be noted that, all the pulse signals are a certain preset frequency point, and different additional phase values bring additional frequency differences, so that signals of different transmitting antennas received by the receiving side antenna are separated at the preset frequency point, and phase information about different transmitting side antennas can be obtained based on spectrum analysis of the receiving side antenna.

Taking the target transmitting antenna 2 as an example, the target transmitting antenna 2 transmits N pulse signals in total, and the N pulse signals are respectively phase-added according to N additional phase values in an additional phase sequence corresponding to the target transmitting antenna 2. For example, the additional phases may be 0.5 pi, 1.5 pi, … in order. For the reference transmitting antenna, the additional phases of the N pulse signals may be 0, and for other target transmitting antennas, the additional phase sequence may include N additional phase values that change according to a certain rule. The same applies to calibrating the transmit antennas.

The additional phase of each transmit antenna is also different for each transmit pulse. Taking the ith transmitting antenna as an example, the additional phase is 2 pi k/M, where i is the transmitting antenna index, k is the pulse index, M is the number of phase sets supported by the phase shifter, e.g. the phase shifter is 6 bits, then m=2 ⁶ ＝64。

In a specific application scenario, the transmitting antennas 1-3 respectively transmit two pulse signals, and the additional phase values are as follows: pulse 1: t1: 0. t2:0.5 pi, T3:1.5 pi; pulse 2: t1: 0. t2: pi, T3:3 pi.

Step S223: and obtaining the amplitude and phase calibration data of the plurality of target antennas based on the inter-group calibration data and the intra-group calibration data.

The inter-group calibration data may be used to align other target antennas in one target antenna group with the reference antenna, and the intra-group calibration data may be used to align other reference antennas with the reference antenna, so that the amplitude-phase calibration data of each target antenna can be obtained based on the inter-group calibration data and the intra-group calibration data.

The above steps are performed at a certain frequency point, and in some embodiments, the detection signal includes detection signals at a plurality of preset frequency points when the detection is performed. Therefore, for a plurality of preset frequency points, the method can be executed once under each preset frequency point: and controlling each transmitting side antenna to transmit a corresponding amplitude-phase calibration signal of the preset frequency point, acquiring a calibration signal to be analyzed under the preset frequency point, and acquiring amplitude-phase calibration data under the preset frequency point by utilizing the phase information of the calibration signal to be analyzed, thereby acquiring the amplitude-phase calibration data under each frequency point. The operation at each preset frequency point may be the same.

In a specific application scenario, the plurality of target antennas include target receiving antennas, the plurality of target antennas include a plurality of target antenna groups, each target antenna group corresponds to a calibration transmitting antenna, and a preset position relationship exists between two antennas with corresponding relationships. And the calibration transmitting antennas corresponding to all the target antennas transmit N pulses simultaneously to serve as amplitude and phase calibration signals. And at the moment, spectrum analysis is carried out on all target receiving antennas along (N pulses) respectively in a DDMA mode, and a peak value corresponding to each calibration transmitting antenna appears in the spectrum of each target receiving antenna.

According to the scheme, the calibration of the target transmitting antenna relative to the reference transmitting antenna and the calibration of the target receiving antenna relative to the reference receiving antenna under different frequency points can be realized.

Referring to fig. 4, fig. 4 is a schematic diagram of an embodiment of a target antenna array and a calibration antenna array in the present application.

In fig. 4, a "mouth" shaped target antenna array is shown, where the target antenna array and the calibration antenna array are disposed opposite to each other, where the target antenna array includes three target transmitting antenna groups of Tx1_group, tx2_group, tx3_group, and two target receiving antenna groups of Rx1_group and Rx2_group, and where the target antenna array further includes a dummy antenna for aligning the target receiving antenna and the target transmitting antenna. The calibration antenna array comprises a receiving antenna 1, a receiving antenna 2, a receiving antenna 3, a transmitting antenna 1 and a transmitting antenna 2. The receiving antenna 1 is a calibration antenna corresponding to Tx1_group, the receiving antenna 2 is a calibration antenna corresponding to Tx2_group, the receiving antenna 3 is a calibration antenna corresponding to Tx3_group, the transmitting antenna 1 is a calibration antenna corresponding to Rx1_group, and the transmitting antenna 2 is a calibration antenna corresponding to Rx 2_group.

Referring to fig. 5, fig. 5 is a flowchart illustrating an antenna array calibration method according to another embodiment of the present application. Specifically, the method may further comprise the steps of:

step S510: and acquiring a coupling calibration signal received by the target receiving antenna in a darkroom environment.

The antenna array calibration method may further include step S510 and step S520 on the basis of any of the foregoing embodiments. The execution of steps S510-S520 may be performed at any step prior to detection with the target antenna array.

The plurality of target antennas comprise at least one target transmitting antenna and at least one target receiving antenna, the coupling calibration signals are transmitted by the target transmitting antennas in a darkroom environment, and the calibration equipment can also control the target transmitting antennas to transmit the coupling calibration signals. The darkroom environment can be considered as the signal emitted by the target transmitting antenna is absorbed when contacting the darkroom environment, and the signal can not emit reflection or refraction to generate echo signal and then be received by the target receiving antenna.

In a specific application scenario, the darkroom is a special room formed by the wave absorbing material and the metal shielding body, and the coupling calibration signal sent by the target transmitting antenna is completely absorbed when the coupling calibration signal contacts the wall, the ceiling, the ground and the like of the darkroom.

Step S520: and obtaining coupling compensation data of the target antenna array according to the coupling calibration signal received by the target receiving antenna.

The coupling calibration signal received by the target receiving antenna can reflect the signal transmission condition between the target receiving antenna and the target transmitting antenna in the target antenna array.

It will be appreciated that a portion of the coupled calibration signal from the target transmit antenna is not absorbed by the darkroom environment, but is received by the target receive antenna. When the target antenna array is used for detecting and imaging the object to be detected, imaging is carried out according to the detection echo signals received by the receiving antennas in the target antenna array. If the detection signal transmitted by the transmitting antenna is directly received by the receiving antenna, imaging of the detection echo signal is affected, so that coupling compensation data obtained according to the coupling calibration signal directly received by the target receiving antenna can be used for eliminating the influence of the directly received detection signal on imaging.

The above steps are performed at a certain frequency point, and in some embodiments, the detection signal includes detection signals at a plurality of preset frequency points when the detection is performed. Therefore, for a plurality of preset frequency points, the steps can be executed once under each preset frequency point, and the operation for each preset frequency point can be the same.

It will be appreciated that the transmit antenna is denoted as N _T The receiving antenna is denoted as N _R The frequency point is denoted as N _F Co-composition N _T *N _R *N _F Combinations used in the detection process, wherein each group may be added with some inconsistent phases due to inconsistent channels, coupling among channels and the like, so as to cause imaging unfocused, and each group may need to be subjected to amplitude phase calibration/coupling calibration to form amplitude phase calibration data/coupling compensation data with the size of N _T *N _R *N _F 。

In a specific application scenario, the obtained coupling compensation data is a three-dimensional table MutualComp [ Tx Num ] [ Rx Num ] [ Frequency Num ], and the three dimensions respectively represent a transmitting antenna, a receiving antenna and a transmitting Frequency point. The obtained three-dimensional table may be corrected, for example, by directly zeroing a value smaller than a certain threshold.

Referring to fig. 6, fig. 6 is a flowchart illustrating a method for calibrating an antenna array according to another embodiment of the present application. Specifically, the method may further comprise the steps of:

step S610: and obtaining detection echo data by using the detection echo signals received by each target receiving antenna.

The antenna array calibration method may further include steps S610 to S630 on the basis of any of the foregoing embodiments.

The calibration device in the application can control each target transmitting antenna to transmit signals, for example, control each target transmitting antenna to transmit detection signals in a time-sharing manner. The detection signal comprises a plurality of pulse signals at preset frequency points, each target transmitting antenna transmits in a time-sharing mode, and no additional phase exists in the detection signal. The detection echo signal is an echo signal of the detection signal, the detection signal is used for detecting an object to be detected, and the object to be detected can reflect, refract and the like on the detection signal, so that the detection echo signal is formed.

Specifically, the detection echo signal may be subjected to analog-to-digital conversion to obtain detection echo data, where the detection echo data may be used to image an object to be detected, so that a user may determine whether a detection target, for example, a security inspection forbidden article, exists.

Step S620: and calibrating the detected echo data by using the calibration data to obtain the data to be imaged.

The calibration data may include, among other things, amplitude and phase calibration data. The calibration data is used to calibrate the target antenna array to enable accurate imaging of the object to be detected.

In some embodiments, the calibration data may also include coupling compensation data.

In some embodiments, prior to step S620, the method may further include: and obtaining real-time calibration data about the target antenna array by utilizing reference echo signals received by reference receiving antennas in at least one group of reference networks, wherein the reference echo signals are received by the reference receiving antennas, and the reference signals transmitted by the reference transmitting antennas are transmitted to the reference receiving antennas through an attenuation network. The calibration data may also include the real-time calibration data described above.

The reference network comprises a reference transmitting antenna, a reference receiving antenna and an attenuation network connected between the reference transmitting antenna and the reference receiving antenna. The target antenna array may be divided into several regions, and the reference transmit antenna and the reference receive antenna may belong to the same region.

In a specific application scenario, the target antenna array is divided into a plurality of areas according to the receiving aperture formed by the target antenna array, and the reference transmitting antenna and the reference receiving antenna in one reference network may belong to the same aperture area.

Any receiving antenna in the target antenna array can be a reference receiving antenna, and further, the target receiving antenna serving as the reference antenna in the amplitude-phase calibration process can be selected as the reference receiving antenna. Any transmitting antenna in the target antenna array can be a reference transmitting antenna, and further, the target transmitting antenna serving as the reference antenna in the amplitude-phase calibration process can be selected as the reference transmitting antenna. The reference transmit antennas and the reference receive antennas in a reference network are selected within the same area.

If a plurality of sets of reference networks are selected, each set of reference networks is processed separately, and a reference echo signal for the target antenna array is obtained based on the reference echo signal obtained by using each set of reference networks. Further, the multiple groups of reference networks may each belong to a different area in the target antenna array, or at least some of the reference networks may all belong to the same area. For example, the target antenna array includes four regions a-D, a reference transmit antenna is selected from each region and four reference networks are formed with reference receive antennas, the four reference networks belonging to different regions.

It should be noted that, the reference receiving antenna and the reference transmitting antenna in the reference network do not participate in the transmission and reception of the detection signal in the detection process. The transmission and reception of the reference signal is also performed during the detection process.

Specifically, for each reference network, carrying out phase solution on the reference echo signal received by the reference receiving antenna to obtain sixth phase information of the reference echo signal received by the reference receiving antenna in the reference network; and obtaining real-time calibration data about the target antenna array based on the sixth phase information and seventh phase information corresponding to the attenuation network, wherein the real-time calibration data is used for calibrating inherent errors of the target antenna array in the current detection process. The seventh phase information corresponding to the attenuation network may represent a phase of the reference signal in the attenuation network due to a time delay, which belongs to an inherent attribute of the attenuation network.

It should be noted that the calibration data includes two types, one is fixed, for example, the coupling compensation data and the amplitude calibration data are inherent properties of the target antenna array, and the other is variable according to the detection, for example, the real-time calibration data are changed during each detection. Therefore, for the first type, the calibration data corresponding to the current detection needs to be calculated once and then can be used in each detection process, and for the second type, the calibration data corresponding to the current detection needs to be calculated together.

In a specific application scenario, let phi 1 be the phase difference generated when the radio frequency source goes to the transmitting channel, phi 2 be the phase difference generated when the present vibration source goes to the receiving channel, phi 3 be the phase generated by the attenuation network due to time delay, and perform phase solving on the ADC signal received by the reference receiving antenna, and record phi, then phi 1+ phi 2 = phi-phi 3. Phi 1+ phi 2 can represent the phase difference generated when the radio frequency source goes to the transmitting channel and the phase difference generated when the local oscillator source goes to the receiving channel, and is the inherent error of the target antenna array in the current detection process.

In a specific application scenario, the detection calibration data includes amplitude calibration data, coupling compensation data, and real-time calibration data. And calibrating the detection echo data by using the detection calibration data, thereby obtaining the data to be imaged.

In some embodiments, the method may further comprise preprocessing the detected echo data prior to calibrating the detected echo data with the detected calibration data. Wherein the preprocessing includes filtering and/or weighting.

Specifically, the detected echo data (ADC data, analog-to-digital conversion data) is filtered by a filter, which may be an FIR filter (Finite Impulse Response filter, non-recursive filter, also called finite length unit impulse response filter) or the like. The influence of the interference target on the imaging result can be reduced through filtering processing.

Specifically, the weight adjustment is used for setting corresponding weights for receiving antennas at different positions in the target antenna array. The influence of specular reflection can be restrained through weight adjustment, so that illumination is more uniform.

Step S630: imaging is carried out by utilizing the data to be imaged, and a detection image is obtained.

Wherein the detection image can be used for a user to check to determine whether the object to be detected contains a detection target.

In a specific application scenario, in the detection image, different types of metal objects perform differently, and security check personnel can judge whether personnel passing through the security check area carry forbidden objects and the types of the forbidden objects carried according to the detection image.

Further, imaging with the data to be imaged, obtaining the detection image may include: gridding the imaging area, calculating to obtain the occupation state and the scattering coefficient of each grid in the imaging area based on the data to be imaged, and obtaining a detection image according to the occupation state and the scattering coefficient of each grid in the imaging area.

In a specific application scenario, the imaging area is gridded, and the occupation state of each grid and the scattering coefficient of the target in the grid are solved by adopting a BP back projection method, namely, the scattering coefficient delta xyz in the space grid is = ΣΣs (T, R, F) ×h (T, R, F, x, y, z), wherein s is calibrated original data, T, R, F respectively represents three dimensions of a transmitting antenna, a receiving antenna and a transmitting frequency, h is a corresponding matched filtering function, and x, y and z represent coordinates of the grid.

The time-sharing transmitting mode is adopted, so that orthogonality of detection SIGNALs in the time dimension is easy to realize, and meanwhile, all receiving antennas receive simultaneously, so that higher SNR (SIGNAL-NOISE RATIO) and dynamic response range can be realized, and the method is concretely as follows: each transmitting antenna transmits signals in turn, and then all receiving antennas simultaneously receive data with the data size of N _T *N _R *N _F *N _sample Wherein N is _T For transmitting the number of antennas N _R For receiving the number of antennas N _F Is the number of frequency points, N _sample The number of samples per bin.

Referring to fig. 7, fig. 7 is a schematic diagram of an embodiment of a detection image of the present application.

Fig. 7 (a) shows the simulation imaging result of the detection image, and fig. 7 (b) shows the detection image.

In a specific application scenario, the target antenna array is used for transmitting millimeter wave signals, so that the target antenna array can be used for security inspection imaging, the detection image is used for a user to check, whether the security inspection object in the security inspection area carries the controlled object or not is judged, and different types of objects are reflected differently in the detection image, so that the user can judge the type of the controlled object according to the detection image.

Referring to fig. 8, fig. 8 is a schematic diagram of a frame of an embodiment of an antenna array of the present application.

In this embodiment, the antenna array 80 is disposed on a plane, and each point in the figure represents an antenna. The antenna array 80 includes a plurality of receiving antenna groups 81 and a plurality of transmitting antenna groups 82.

Wherein, the plurality of receiving antenna groups 81 are arranged at intervals along the first direction, each receiving antenna group 81 includes a plurality of receiving antennas 811 arranged along the second direction, the plurality of receiving antennas 811 are unevenly arranged, and the intervals between adjacent receiving antenna pairs near two ends of the receiving antenna group 81 are smaller than the intervals between adjacent receiving antenna pairs far from two ends of the receiving antenna group 81.

Wherein, the plurality of receiving antenna groups 81 are disposed between at least one group of receiving antenna group pairs, two receiving antenna groups 81 included in different receiving antenna group pairs are different, the number of transmitting antenna groups 82 between each group of receiving antenna group pairs is at least two and are disposed along the second direction at intervals by a second distance, the transmitting antenna groups 82 include a plurality of transmitting antennas disposed along the first direction at intervals, and the second distance is greater than the interval between adjacent receiving antenna pairs in the receiving antenna groups 81.

Wherein, the antennas in columns 1-4 in the figure are receiving antennas 811, each receiving antenna 811 constitutes a receiving antennaThe antennas in the lines 81,5-8 are transmit antennas 821 and the transmit antennas 821 between a group of pairs of receive antennas in each line form a transmit antenna group 82. D in the figure ₁ Represents a first distance, d ₂ Representing the second distance. As shown in fig. 8, there are a total of 8 transmit antenna groups, denoted as tx_line1-tx_line8, respectively.

In some embodiments, the number of the receiving antenna group pairs is at least two, the plurality of transmitting antenna groups 82 is divided into a plurality of antenna groups 83, each antenna group includes one transmitting antenna group 82 between each receiving antenna group pair, and the transmitting antenna groups 82 included in each antenna group 83 are arranged along the first direction.

The number of the transmitting antenna groups 82 included in each antenna group 83 may be two or more, and may be adjusted according to the number of the receiving antenna group pairs.

In some embodiments, the spacing of adjacent pairs of receive antennas in receive antenna group 81 is positively correlated with the distance between the adjacent pairs of receive antennas and the ends of receive antenna group 81.

In some embodiments, the plurality of transmit antenna groups 82 are divided into a plurality of antenna groups 83, each antenna group 83 including one transmit antenna group 82 between each receive antenna group pair, with adjacent transmit antennas 821 in the antenna groups 83 being 4mm apart.

In some embodiments, the first distance is 136mm.

In some embodiments, the second distance is 136mm.

In some embodiments, the first direction and the second direction may be at an angle, and further, perpendicular.

In some embodiments, the spacing between adjacent pairs of receive antennas in receive antenna group 81 is greater than 2mm.

As shown in FIG. 8, each group of transmitting antenna groups 82 adopts a uniform arrangement mode, the horizontal interval between adjacent transmitting antennas 821 is 4mm, the horizontal interval between the transmitting antennas 821 is 4mm, the horizontal length of the gap area between each group is 136mm, the aperture of the transmitting antennas can be 408mm, and better spatial resolution can be realized, specifically, the X-direction position of the transmitting antenna corresponding to Tx_Line1 is 0.006m to 0.13m, the Y-direction position of the transmitting antenna corresponding to Tx_Line2 is 0.048m, the X-direction position of the transmitting antenna corresponding to Tx_Line2 is 0.278m to 0.402m, the Y-direction position of the transmitting antenna corresponding to Tx_Line3 is 0.006m to 0.13m, the X-direction position of the transmitting antenna corresponding to Tx_Line3 is 0.18m, the X-direction position of the transmitting antenna corresponding to Tx_Line4 is 0.18 m, the Y-direction position of the transmitting antenna corresponding to Tx_Line5 is 0.278m to 0.300 m, the Y-direction position of the transmitting antenna corresponding to 0.278m, the X-direction position of the transmitting antenna corresponding to X_Line2 is 0.278m to 0.0.300 m, and the Y-direction position of the X_Line3 is 0.278m, and the Y-direction position of the X-direction position corresponding to 0.0.32 m. The above values may vary with the starting coordinate position, but the relative relationship remains unchanged.

The receiving antennas are arranged in a sparse mode, so that large apertures in the vertical direction can be realized, imaging aliasing in the vertical direction can be restrained, the interval values between every two adjacent receiving antennas are distributed in an equi-differential mode, the imaging aliasing can be restrained well in simulation, and the array is as follows: the X position of column 1 is 0mm, the X position of the second column is 0.136m, the X position of the third column is 0.272m, and the X position of the fourth column is 0.408m. The Y-axis distribution of each group of receiving antenna groups 81 satisfies the following rule: when 1< =i and i < =31, Y (i+1) =y (i) +i, Y (1) =0, i is the index of the receiving antenna; otherwise, let m=i-31, YM (m+1) =ym (m) -m, YM (1) =496. Multiplying each of the calculated Y (i) and YM (m) by 1mm gives its corresponding spatial position. If the two receiving antennas are smaller than 2mm, the interval between the receiving antennas is properly enlarged to be larger than 2mm or the two receiving antennas are combined. The above values may vary with the starting coordinate position, but the relative relationship remains unchanged.

By introducing the design of the sparse antenna array designed as above, the antenna aperture larger than that of the uniform array with the same number can be obtained, the spatial resolution is improved, and meanwhile, the adjacent receiving antenna pairs are arranged in the sparse antenna array, so that the wave number K can be enlarged _x 、K _y Thereby solving the problem of imaging mould under large field anglePaste problems. And the three-dimensional reconstruction of the space object can be better realized by the mode of the sparse array antenna layout.

Referring to fig. 9, fig. 9 is a schematic diagram of an embodiment of an antenna calibration system according to the present application.

In this embodiment, the antenna calibration system 90 includes an antenna array structure 91 and a calibration device 92, where the calibration device 92 is configured to perform the antenna array calibration method in any of the above embodiments to calibrate a plurality of target antennas in the antenna array structure 91. The antenna array structure 91 may be any of the antenna arrays of the previous embodiments.

Referring to fig. 10, fig. 10 is a schematic diagram of a frame of an embodiment of the calibration apparatus of the present application.

In this embodiment, the calibration device 100 includes a memory 101 and a processor 102, wherein the memory 101 is coupled to the processor 102. In particular, the various components of the calibration apparatus 100 may be coupled together by a bus, or the processor 102 of the calibration apparatus 100 may be coupled to each other individually. The calibration device 100 may be any device having processing capabilities, such as a computer, tablet, cell phone, etc.

The memory 101 is used for storing program data executed by the processor 102, data during processing by the processor 102, and the like. For example, first phase information, second phase information, etc. Wherein the memory 101 comprises a non-volatile storage portion for storing the above-mentioned program data.

The processor 102 controls the operation of the calibration device 100, the processor 102 may also be referred to as a CPU (Central Processing Unit ). The processor 102 may be an integrated circuit chip having signal processing capabilities. Processor 102 may also be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. In addition, the processor 102 may be commonly implemented by a plurality of circuit-forming chips.

The processor 102 is operable to execute instructions to implement any of the antenna array calibration methods described above by invoking program data stored in the memory 101.

Referring to FIG. 11, FIG. 11 is a schematic diagram illustrating an embodiment of a computer readable storage medium of the present application.

In this embodiment, the computer readable storage medium 110 stores processor executable program data 111, which can be executed to implement any of the antenna array calibration methods described above.

The computer readable storage medium 110 may be a medium capable of storing program data, such as a usb disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or may be a server storing the program data, where the server may send the stored program data to another device for execution, or may also self-execute the stored program data.

In some embodiments, the computer readable storage medium 110 may also be a memory as shown in FIG. 10.

The foregoing description is only of embodiments of the present application, and is not intended to limit the scope of the patent application, and all equivalent structures or equivalent processes using the descriptions and the contents of the present application or other related technical fields are included in the scope of the patent application.

Claims (18)

1. A method of calibrating an antenna array, the method comprising:

acquiring calibration signals to be analyzed related to a plurality of target antennas in a target antenna array, wherein the plurality of target antennas comprise at least one of target transmitting antennas and target receiving antennas, each target antenna corresponds to one calibration antenna in the calibration antenna array respectively, each target antenna has opposite transceiving properties with the corresponding calibration antenna and has a preset position relationship, and the calibration signals to be analyzed comprise amplitude-phase calibration signals transmitted between the plurality of target antennas and the calibration antennas and are received by the antennas serving as receiving sides in the plurality of target antennas and the calibration antennas;

And acquiring the amplitude and phase calibration data of the target antennas by using the phase information of the calibration signals to be analyzed.

2. The method of claim 1, wherein the plurality of target antennas are divided into a plurality of target antenna groups, different target antenna groups corresponding to different calibration antennas, each target antenna in the same target antenna group corresponding to the same calibration antenna; and/or, the preset position relation comprises a far-field position relation and a zero-degree position relation.

3. The method according to claim 1 or 2, wherein the plurality of target antennas are divided into a plurality of target antenna groups, one of the target antennas in the target antenna groups is a reference antenna corresponding to the target antenna group, the target antennas in the target antenna groups other than the reference antenna are other target antennas in the target antenna groups, one of all the reference antennas is a reference antenna, and the reference antennas other than the reference antenna are other reference antennas;

the obtaining the amplitude and phase calibration data of the plurality of target antennas by using the phase information of the calibration signal to be analyzed includes:

for each target antenna group, obtaining intra-group calibration data of other target antennas in the target antenna group relative to the reference antenna by using a first phase difference between target amplitude calibration signals and reference amplitude calibration signals of other target antennas in the target antenna group, wherein the target amplitude calibration signals of the other target antennas are amplitude calibration signals transmitted between the other target antennas and calibration antennas corresponding to the other target antennas, and the reference amplitude calibration signals are amplitude calibration signals transmitted between the reference antennas and the calibration antennas corresponding to the reference antennas;

For each other reference antenna, obtaining inter-group calibration data of the other reference antenna relative to the reference antenna by using a second phase difference between a first amplitude-phase calibration signal of the other reference antenna and the reference amplitude-phase calibration signal of the other reference antenna and a third phase difference between a reference amplitude-phase calibration signal and a second amplitude-phase calibration signal of the other reference antenna, wherein the first amplitude-phase calibration signal of the other reference antenna is an amplitude-phase calibration signal transmitted between the reference antenna and a calibration antenna corresponding to the other reference antenna, and the reference amplitude-phase calibration signal is an amplitude-phase calibration signal transmitted between the reference antenna and a calibration antenna corresponding to the reference antenna, and the second amplitude-phase calibration signal of the other reference antenna is an amplitude-phase calibration signal transmitted between the other reference antenna and a calibration antenna corresponding to the reference antenna;

and obtaining the amplitude phase calibration data of the target antennae based on the inter-group calibration data and the intra-group calibration data.

4. The method of claim 3, wherein using the first phase difference between the target and reference amplitude calibration signals for the other target antennas in the target antenna group to obtain the intra-group calibration data for the other target antennas in the target antenna group relative to the reference antenna comprises:

Performing spectrum analysis on the amplitude and phase calibration signal received by a first receiving side antenna to obtain first phase information of the target amplitude and phase calibration signal and second phase information of the reference amplitude and phase calibration signal, wherein the first receiving side antenna is an antenna serving as a receiving side in the target antenna group and a corresponding calibration antenna;

determining a phase difference between the other target antenna and the reference antenna as the intra-group calibration data based on a first phase difference between the first phase information and the second phase information;

the obtaining the inter-group calibration data of the other reference antenna relative to the reference antenna by using a second phase difference between the first amplitude-phase calibration signal of the other reference antenna and the reference amplitude-phase calibration signal of the other reference antenna and a third phase difference between a reference amplitude-phase calibration signal and the second amplitude-phase calibration signal of the other reference antenna comprises:

performing spectrum analysis on an amplitude-phase calibration signal received by a second receiving side antenna to obtain second phase information of the reference amplitude-phase calibration signal, third phase information of the first amplitude-phase calibration signal, fourth phase information of the reference amplitude-phase calibration signal and fifth phase information of the second amplitude-phase calibration signal, wherein the second receiving side antenna is an antenna serving as a receiving side among the reference antenna, each other reference antenna, calibration antennas corresponding to the reference antenna and calibration antennas corresponding to the other reference antennas;

A phase difference between the other reference antenna and the reference antenna is determined as the inter-group calibration data based on a second phase difference between the second phase information and the third phase information, and a third phase difference between the fourth phase information and the fifth phase information.

5. The method according to claim 1, wherein the method further comprises:

and controlling each transmitting side antenna to transmit signals by taking the antenna serving as the transmitting side in the plurality of target antennas and the calibration antenna as the transmitting side antenna.

6. The method of claim 5, wherein the transmitted signals include the amplitude and phase calibration signals, and wherein controlling each of the transmit side antennas to transmit signals comprises:

determining different additional phase sequences for each transmitting side antenna according to an additional phase value rule, wherein the additional phase sequences comprise a preset number of additional phase values;

respectively transmitting the preset number of pulse signals as the amplitude-phase calibration signals by utilizing the transmitting side antennas, wherein the preset number of pulse signals are respectively subjected to phase addition according to additional phase values contained in the additional phase sequences;

And/or, for a plurality of preset frequency points, executing once under each preset frequency point: and controlling each transmitting side antenna to transmit the amplitude and phase calibration signal corresponding to the preset frequency point, acquiring the calibration signal to be analyzed under the preset frequency point, and acquiring the amplitude and phase calibration data under the preset frequency point by utilizing the phase information of the calibration signal to be analyzed.

7. The method of claim 1, wherein the plurality of target antennas comprises at least one target transmit antenna and at least one target receive antenna, the method further comprising:

acquiring a coupling calibration signal received by the target receiving antenna in a darkroom environment, wherein the coupling calibration signal is transmitted by the target transmitting antenna in the darkroom environment;

and obtaining coupling compensation data of the target antenna array according to the coupling calibration signal received by the target receiving antenna.

8. The method of claim 1, wherein the plurality of target antennas comprises at least one target transmit antenna and at least one target receive antenna, the method further comprising:

obtaining detection echo data by using detection echo signals received by the target receiving antennas, wherein the detection echo signals are echo signals of detection signals transmitted by the target transmitting antennas in a time-sharing manner;

Calibrating the detection echo data by using detection calibration data to obtain data to be imaged, wherein the detection calibration data comprises the amplitude calibration data;

and imaging by using the data to be imaged to obtain a detection image.

9. The method of claim 8, wherein the detection calibration data further comprises real-time calibration data; the target antenna array includes at least one set of reference networks, the reference networks include a reference transmitting antenna, a reference receiving antenna, and an attenuation network connected between the reference transmitting antenna and the reference receiving antenna, the reference transmitting antenna and the reference receiving antenna belong to a same area in the target antenna array, the method further includes, before calibrating the detected echo data with detected calibration data to obtain data to be imaged:

and obtaining the real-time calibration data about the target antenna array by using at least one group of reference echo signals received by the reference receiving antennas in the reference network, wherein the reference echo signals are echo signals of reference signals transmitted by the reference transmitting antennas.

10. The method of claim 9, wherein said deriving said real-time calibration data for said target antenna array using reference echo signals received by said reference receive antennas in at least one set of said reference networks comprises:

carrying out phase solution on the reference echo signals received by the reference receiving antennas in each reference network to obtain sixth phase information of the reference echo signals received by the reference receiving antennas in the reference network;

and obtaining real-time calibration data about the target antenna array based on the sixth phase information and seventh phase information corresponding to the attenuation network, wherein the real-time calibration data is used for calibrating inherent errors of the target antenna array in the current detection process.

11. The method of claim 8, wherein prior to calibrating the detected echo data with detected calibration data to obtain data to be imaged, the method further comprises:

preprocessing the detected echo data, wherein the preprocessing comprises filtering processing and/or weight adjustment, and the weight adjustment is used for setting corresponding weights for the target receiving antennas at different positions; and/or the number of the groups of groups,

Imaging by using the data to be imaged, and obtaining a detection image comprises the following steps:

gridding the imaging region;

calculating the occupation state and the scattering coefficient of each grid in the imaging area based on the data to be imaged;

and obtaining a detection image according to the occupation state and the scattering coefficient of each grid in the imaging area.

12. The method of claim 8, wherein the detection signals comprise detection signals corresponding to a plurality of preset frequency points respectively; and/or the detection calibration data further comprises coupling compensation data.

13. An antenna calibration system comprising an antenna array structure and a calibration device, wherein the calibration device is configured to perform the antenna array calibration method of any one of claims 1-12 to calibrate a plurality of target antennas in the antenna array structure, the antenna array structure being disposed on a plane, the antenna array structure comprising:

the plurality of receiving antenna groups are arranged at intervals of a first distance along a first direction, the plurality of receiving antenna groups comprise a plurality of receiving antennas arranged along a second direction, and the intervals of adjacent receiving antenna pairs close to two ends of the receiving antenna groups are smaller than the intervals of adjacent receiving antenna pairs far from two ends of the receiving antenna groups;

The plurality of transmitting antenna groups are arranged between at least one group of receiving antenna group pairs, two receiving antenna groups contained in different receiving antenna group pairs are different, each group of transmitting antenna groups between the receiving antenna group pairs are at least two and are arranged along the second direction at intervals by a second distance, each transmitting antenna group comprises a plurality of transmitting antennas arranged along the first direction at intervals, and the second distance is larger than the interval between the adjacent receiving antenna groups in the receiving antenna groups.

14. The system of claim 13, wherein the number of said pairs of receive antennas is at least two, and wherein said plurality of transmit antennas is divided into a plurality of antenna groups, each of said antenna groups including one of said transmit antennas between each of said pairs of receive antennas, said transmit antennas included in each of said antenna groups being aligned in said first direction;

and/or, the interval of the adjacent receiving antenna pairs in the receiving antenna group is positively correlated with the distance between the adjacent receiving antenna pairs and the two ends of the receiving antenna group.

15. The system of claim 13, wherein said plurality of transmit antenna groups are divided into a plurality of antenna groups, each of said antenna groups comprising one of said transmit antenna groups between each of said receive antenna group pairs, a distance between adjacent ones of said transmit antenna groups being 4mm;

And/or, the first distance is 136mm;

and/or, the second distance is 136mm;

and/or the interval between the adjacent receiving antenna pairs in the receiving antenna group is larger than 2mm.

16. An antenna array, characterized in that the antenna array is an antenna array structure comprised in the system according to any of claims 14-16.

17. A calibration device comprising a memory and a processor coupled to each other, the processor being configured to execute program instructions stored in the memory to implement the antenna array calibration method of any one of claims 1 to 12.

18. A computer readable storage medium having stored thereon program instructions, which when executed by a processor, implement the antenna array calibration method of any of claims 1 to 12.

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