CN111694073B

CN111694073B - Circumferential scanning imaging security check calibrating device

Info

Publication number: CN111694073B
Application number: CN202010566878.7A
Authority: CN
Inventors: 任百玲; 孙兆阳; 张焱; 刘昊; 许戎戎
Original assignee: BEIJING AEROSPACE JINTAI XINGCE TECHNOLOGY CO LTD; Beijing Research Institute of Telemetry; Aerospace Long March Launch Vehicle Technology Co Ltd
Current assignee: BEIJING AEROSPACE JINTAI XINGCE TECHNOLOGY CO LTD; Beijing Research Institute of Telemetry; Aerospace Long March Launch Vehicle Technology Co Ltd
Priority date: 2020-06-19
Filing date: 2020-06-19
Publication date: 2022-12-13
Anticipated expiration: 2040-06-19
Also published as: CN111694073A

Abstract

The invention discloses a circle scanning imaging security check calibration device, which comprises: 4 calibration antenna elements and 4 single pole double throw switches; 4 calibration antenna units, namely a B-surface receiving antenna calibration unit, an A-surface receiving antenna calibration unit, a B-surface transmitting antenna calibration unit and an A-surface transmitting antenna calibration unit; the phase errors of the transmitting array channel and the receiving array channel are obtained by adopting the mode that the B-surface receiving antenna calibration unit and the A-surface receiving antenna calibration unit receive the transmitting signals or the B-surface transmitting antenna calibration unit and the A-surface transmitting antenna calibration unit transmit the signals, the phase errors are extracted without carrying special equipment in the installation and debugging process, and the calibration can be completed after the security inspection system is started.

Description

Circumferential scanning imaging security check calibrating device

Technical Field

The invention relates to a circle scanning imaging security check calibration device, and belongs to the technical field of millimeter wave security check imaging.

Background

The currently known circular scanning imaging security inspection system devices all adopt a calibration method of a calibration plate or a calibration line. During the calibration process, a calibration plate or a calibration line needs to be placed on the central axis of the circular scanning imaging security inspection system. The installation and debugging are complex and time-consuming, and the installation and debugging equipment is not beneficial to public places such as airports and the like. Generally, in the using process, regular calibration and debugging are often needed, and the mode of using the calibration line of the calibration plate is not favorable for convenient calibration and debugging. Based on the reasons, the invention provides the calibration method and the calibration device which are higher in precision and more convenient and flexible in calibration.

Disclosure of Invention

The technical problem solved by the invention is as follows: the defects of the prior art are overcome, the calibration device of the circular scanning imaging security inspection system is provided, the phase error extraction does not need to carry special calibration equipment in the installation and debugging process, and the calibration can be completed after the security inspection system is started.

The technical scheme of the invention is as follows: a circle scanning imaging security inspection system calibration device comprises: 4 antenna calibration units and 4 single-pole double-throw switches;

4 calibration antenna units, namely a B-surface receiving antenna calibration unit, an A-surface receiving antenna calibration unit, a B-surface transmitting antenna calibration unit and an A-surface transmitting antenna calibration unit;

a first single-pole double-throw switch is arranged between the input end of the receiver of the A-side transceiver module and the output ends of the A-side receiving antenna array and the B-side receiving antenna calibration unit, so that the input end of the receiver of the A-side transceiver module can be connected with the output end of the A-side receiving antenna array and can also be connected with the output end of the B-side receiving antenna calibration unit through a radio-frequency cable;

a second single-pole double-throw switch is arranged between the output end of the transmitter of the A-side transceiver module and the input ends of the A-side transmitting antenna array and the B-side transmitting antenna calibration unit, so that the output end of the transmitter of the A-side transceiver module can be selectively connected with the input end of the A-side transmitting antenna array and can also be connected with the input end of the B-side transmitting antenna calibration unit through a radio-frequency cable;

a third single-pole double-throw switch is arranged between the input end of the receiver of the B-face transceiver module and the output ends of the B-face receiving antenna array and the A-face receiving antenna calibration unit, so that the input end of the receiver of the B-face transceiver module can be connected with the output end of the B-face receiving antenna array and can also be connected with the output end of the A-face receiving antenna calibration unit through a radio-frequency cable;

a fourth single-pole double-throw switch is arranged between the output end of the transmitter of the B-side transceiver module and the input ends of the B-side transmitting antenna array and the A-side transmitting antenna calibration unit, so that the output end of the transmitter of the B-side transceiver module can be selectively connected with the input end of the B-side transmitting antenna array and can also be connected with the input end of the A-side transmitting antenna calibration unit through a radio frequency cable;

transmitting antenna array B on B surface ₁ Side-mounted B-side transmitting antenna calibration unit B' ₁ Calibration Unit B 'for B-side transmitting antenna' ₁ The A-plane receiving antenna array A is formed by the A-plane receiving antenna array A and the transmitter of the A-plane receiving and transmitting module ₂ The calibration channel of (2);

receiving antenna array B on B side ₂ Side-mounted B-side receiving antenna calibration unit B' ₂ And a B-side receiving antenna calibration unit B' ₂ The A-surface transmitting antenna array A is formed by the A-surface transmitting antenna array A and the receiver of the A-surface receiving and transmitting module ₁ The calibration channel of (1);

transmitting antenna array A on A surface ₁ Side-mounted A-side transmitting antenna calibration unit A' ₁ A-side transmit antenna calibration unit A' ₁ The B-plane receiving antenna array B is formed by the transmitter of the B-plane transceiver module ₂ The calibration channel of (2);

receiving antenna array A on A surface ₂ Side-mounted A-side receiving antenna calibration unit A' ₂ Receive antenna calibration Unit A 'of side A' ₂ The B-plane transmitting antenna array B is formed by the B-plane transmitting antenna array B and the receiver of the B-plane transmitting-receiving module ₁ The calibration channel of (1);

a-surface transmitting antenna array A ₁ A-side receiving antenna array A ₂ The first plane A and the second plane A are jointly arranged, and the A plane is marked; b-surface transmitting antenna array B ₁ B-side receiving antenna array B ₂ The two planes are jointly arranged on a second plane B, and the B plane is marked; a first plane A andthe second planes B are oppositely arranged in parallel and can rotate along the rotating shaft under the drive of the servo motor; the rotating shaft is positioned between the first plane A and the second plane B and is parallel to the first plane A and the second plane B, and the distance between the rotating shaft and the first plane A is the same as that between the rotating shaft and the second plane B;

the A-plane receiving antenna array has N _R A receiving antenna unit; the receiving period of each antenna unit is T; each receiving antenna unit can be respectively connected with a receiver of the A-surface transceiver module, and a channel is formed as each receiving channel of the A surface;

the A-surface transmitting antenna array has N _T A plurality of transmitting antenna elements; the transmission period of each antenna unit is T; each transmitting antenna unit can be respectively connected with a transmitter of the A-surface transceiver module to form a channel as each transmitting channel of the A-surface;

the B-side receiving antenna array has N _R A receiving antenna unit; the receiving period of each antenna unit is T; each receiving antenna unit can be respectively connected with a receiver of the B-surface transceiver module, and a channel is formed as each receiving channel of the B surface;

the B-side transmitting antenna array has N _T A plurality of transmitting antenna elements; the transmission period of each antenna unit is T; each transmitting antenna unit can be respectively connected with a transmitter of the B-surface transceiver module to form a channel as each transmitting channel of the B surface;

controlling a first single-pole double-throw switch to connect the output end of the A-side receiving antenna array with the input end of a receiver of the A-side transceiving module, and simultaneously controlling a second single-pole double-throw switch to calibrate a B-side transmitting antenna calibration unit B' ₁ The input end is connected with the output end of the A-surface transceiver module transmitter; controlling the A-surface transmitting antenna array not to work; the B-plane transmitting antenna array does not work; the A-surface transmitting antenna calibration unit does not work;

controlling the A-side receiving antenna array to sequentially complete the electrical scanning reception of each unit in the antenna array from top to bottom by taking T as a period, and simultaneously controlling the B-side transmitting calibration antenna unit B' ₁ In the long-hair state with T as the period, N is completed _R After the work of each period T, each receiving channel of the A surface finishes receiving the B surface hairAntenna calibration unit B' ₁ Reception of transmitted signals, output N from the receiver of the A-plane Transceiver Module _R The received signals, respectively denoted as s _RAi ，i＝1,2,…,N _R ；s _RAi Receiving signals for the ith path;

to N _R The method comprises the steps that a path of received signals are sampled respectively, and a plurality of sampling points are obtained after each path of received signals are sampled to form a path of discrete signals; fourier transform is carried out on each path of discrete signal to obtain each path of signal after Fourier transform, and the maximum value of the amplitude of each path of signal after Fourier transform and the position of a sampling point corresponding to the maximum value are determined _{RA_RANGEmaxi} And phase

Determining the distance between the B-surface transmitting calibration antenna unit and the A-surface receiving antenna array unit according to the position of the B-surface transmitting calibration antenna unit and the position of the ith unit in the A-surface receiving antenna array unit, thereby determining the phase compensation quantity corresponding to each unit in the A-surface receiving antenna array; the phase compensation quantity corresponding to each unit in the A-surface receiving antenna array is used for carrying out phase compensation on the sampling point corresponding to the maximum value of the amplitude of each path of signals after Fourier transform

Compensating to obtain the phase delta 1 of the sampling point corresponding to the maximum value of the amplitude of each path of signal after Fourier transform _i ；

According to the sampling point position corresponding to the maximum value of the signal amplitude after each path of Fourier transform _{RA_RANGEmaxi} Determining the phase compensation amount delta 2 corresponding to each path of Fourier transformed signals _i ；

According to the phase delta 1 of the sampling point corresponding to the maximum value of the amplitude of each path of signal after the Fourier transform after compensation _i (ii) a Phase compensation amount delta 2 corresponding to each Fourier-transformed signal _i Determining receiver output N of A-plane transceiver module _R Compensation RA for the phase of the received signal _compensate ；

Secondly, controlling the second single knife pairThe throw switch connects the input end of the A-side transmitting antenna array with the output end of the A-side transceiver module transmitter, and controls the first single-pole double-throw switch to calibrate the B-side receiving antenna calibration unit B' ₂ The output end of the antenna is connected with the input end of the A-side transceiver module receiver to control the B-side transmitting antenna array not to work; the B-surface transmitting antenna calibration unit does not work; the A-surface transmitting antenna calibration unit does not work;

controlling the A-side transmitting antenna array to sequentially finish transmitting each unit in the antenna array from top to bottom by taking T as a period, and simultaneously controlling a B-side receiving antenna calibration unit B' ₂ In the state of taking T as cycle length to finish N _T B-side receiving antenna calibration unit B 'after operation of one period T' ₂ Completing the receiving of the transmitting signals of the units of the A-side transmitting antenna array, and calibrating the unit B 'from the B-side receiving antenna' ₂ Output N _T Receiving signals, respectively denoted as s _TAi ，i＝1,2,…,N _T ；s _TAi Receiving a signal for the ith path;

to N _T The method comprises the steps that a path of received signals are sampled respectively, and a plurality of sampling points are obtained after each path of received signals are sampled to form a path of discrete signals; fourier transform is carried out on each path of discrete signals to obtain each path of signals after Fourier transform, and the maximum value of the amplitude of each path of signals after Fourier transform and the sampling point position TA _ RANGE corresponding to the maximum value are determined _maxi And phase

Determining the distance between the B-surface receiving calibration antenna unit and the A-surface transmitting antenna array unit according to the position of the B-surface receiving antenna calibration unit and the position of the ith unit in the A-surface transmitting antenna array unit, thereby determining the phase compensation amount corresponding to each unit in the A-surface transmitting antenna array; the phase compensation quantity corresponding to each unit in the A-surface transmitting antenna array is used for carrying out Fourier transform on the phase of each path of sampling point corresponding to the maximum value of the signal amplitude

Compensating to obtain compensated signal amplitude after Fourier transformPhase delta 3 of sampling point corresponding to maximum value of degree _i ；

According to the sampling point position TA _ RANGE corresponding to the maximum value of the signal amplitude after each path of Fourier transform _maxi Determining the phase compensation amount delta 4 corresponding to each Fourier transformed signal _i ；

According to the phase delta 3 of the sampling point corresponding to the maximum value of the amplitude of each path of signal after Fourier transform after compensation _i (ii) a Phase compensation amount delta 4 corresponding to each Fourier transformed signal _i Determining the compensation TA of the phase of the transmitted signal of the transmitter of the A-plane transceiver module _compensate ；

Controlling a third single-pole double-throw switch to connect the output end of a B-face receiving antenna array with the input end of a B-face receiving and transmitting module receiver, and simultaneously controlling a fourth single-pole double-throw switch to connect the input end of an A-face transmitting antenna calibration unit with the output end of a B-face receiving and transmitting module transmitter; controlling the B-plane transmitting antenna array not to work; the A-side transmitting antenna array does not work; b, the transmitting antenna calibration unit works;

controlling the B-side receiving antenna array to sequentially complete the electric scanning and receiving of each unit in the antenna array from top to bottom by taking T as a period, and simultaneously controlling the A-side transmitting antenna calibration unit A' ₁ In the state of long hair with 8 mus as period, N is completed _R After 8 mu s periods of operation, each B-side receive channel completes calibration of the A-side transmit antenna calibration unit A' ₁ Reception of the transmitted signal, output N from the receiver of the B-plane Transceiver Module _R Receiving signals, respectively denoted as s _RBi ，i＝1,2,…,N _R ；s _RBi Receiving signals for the ith path;

to N _R Respectively sampling the received signals, obtaining a plurality of sampling points after sampling each received signal to form a discrete signal, carrying out Fourier transform on each discrete signal to obtain signals after Fourier transform, and determining the maximum value of the amplitude of each signal after Fourier transform and the sampling point position RB _ RANGE corresponding to the maximum value _maxi And phase

Determining the distance between the A-surface transmitting calibration unit and the B-surface receiving antenna array unit according to the position of the A-surface transmitting antenna calibration unit and the position of the ith unit in the B-surface receiving antenna array unit, thereby determining the phase compensation quantity corresponding to each unit in the B-surface receiving antenna array; the phase compensation quantity corresponding to each unit in the B-surface receiving antenna array is used for the phase of the sampling point corresponding to the maximum value of the signal amplitude after Fourier transform of each path

Compensating to obtain the phase delta 5 of the sampling point corresponding to the maximum value of the amplitude of each path of signal after Fourier transform _i ；

According to the sampling point position RB _ RANGE corresponding to the maximum value of the signal amplitude after each path of Fourier transform _maxi Determining the phase compensation quantity delta 6 corresponding to each path of signals after Fourier transform _i ；

According to the phase delta 5 of the sampling point corresponding to the maximum value of the amplitude of each path of signal after the compensation and the Fourier transform _i Phase compensation amount Delta 6 corresponding to each Fourier transformed signal _i Determining receiver output N of B-plane transceiver module _R Compensation RB for the phase of the received signal _compensate ；

Finally, controlling a fourth single-pole double-throw switch to connect the input end of the B-face transmitting antenna array with the output end of a B-face transceiver module transmitter, and simultaneously controlling a third single-pole double-throw switch to connect the input end of an A-face receiving antenna calibration unit with the output end of a B-face transceiver module receiver to control the A-face transmitting antenna array not to work; the B-surface transmitting antenna calibration unit does not work; the A-surface transmitting antenna calibration unit does not work;

controlling the B-side transmitting antenna array to sequentially finish transmitting each unit in the antenna array from top to bottom by taking T as a period, and simultaneously controlling the A-side receiving antenna calibration unit A' ₂ In the state of taking T as cycle length to finish N _T After T periods of operation, A-side receiving antenna calibration unit A' ₂ Completing the receiving of the transmitting signals of the units of the B-side transmitting antenna array, and calibrating the unit A 'from the A-side receiving antenna' ₂ Output N _T Receiving signals, respectively denoted as s _TBi ，i＝1,2,…,N _T ；s _TBi Receiving signals for the ith path;

to N _T Respectively sampling the received signals, obtaining a plurality of sampling points after sampling each received signal to form a discrete signal, carrying out Fourier transform on each discrete signal to obtain signals after Fourier transform, and determining the maximum value of the amplitude of each signal after Fourier transform and the position of the sampling point corresponding to the maximum value _{TB_RANGEmaxi} And phase

Determining the distance between the A-surface receiving calibration antenna unit and the B-surface transmitting antenna array unit according to the position of the A-surface receiving antenna calibration unit and the position of the ith unit in the B-surface transmitting antenna array unit, thereby determining the phase compensation quantity corresponding to each unit in the B-surface transmitting antenna array; the phase compensation quantity corresponding to each unit in the B-surface transmitting antenna array is used for carrying out phase compensation on the sampling point corresponding to the maximum value of the amplitude of each path of signals after Fourier transform

Compensating to obtain the phase delta 7 of the sampling point corresponding to the maximum value of the amplitude of each path of signal after Fourier transform _i ；

According to the sampling point position corresponding to the maximum value of the signal amplitude after each path of Fourier transform _{TB_RANGEmaxi} Determining the phase compensation amount delta 8 corresponding to each path of Fourier transformed signals _i ；

According to the phase delta 7 of the sampling point corresponding to the maximum value of the amplitude of each path of signal after the Fourier transform after compensation _i (ii) a Phase compensation amount delta 8 corresponding to each Fourier transformed signal _i Determining a compensation TB for the phase of the transmission signal of the transmitter of the B-plane transceiver module _compensate ；

Outputting N of receiver of A-plane transceiver module _R Compensation RA for the phase of the received signal _compensate Transmitter output of A-plane transceiver moduleN of (A) _T Compensation TA for phase of channel transmitting signal _compensate Receiver output N of B-plane transceiver module _R Compensation RB for the phase of the received signal _compensate And N of transmitter output of B-plane transceiver module _T Compensation quantity TB of road transmitting signal phase _compensate And storing.

Preferably, the receiver output N of the A-plane transceiver module _R Compensation RA for the phase of the received signal _compensate 。

Preferably, the receiver output N of the a-plane transceiver module _R Compensation RA for the phase of the received signal _compensate ＝Δ1 _i *Δ2 _i 。

Preferably, N of transmitter output of the a-plane transceiver module _T Compensation TA for phase of channel transmitting signal _compensate ＝Δ3 _i *Δ4 _i 。

Preferably, the receiver output N of the B-plane transceiver module _R Compensation RB for the phase of the received signal _compensate ＝Δ5 _i *Δ6 _i 。

Preferably, N of transmitter output of B-plane transceiver module _T Compensation quantity TB of road transmitting signal phase _compensate ＝Δ7 _i *Δ8 _i 。

Preferably, T is 8. Mu.s.

Preferably, the B-side transmitting antenna calibration unit B' ₁ The state of long hair with T as the cycle means that: b-plane transmitting calibration antenna unit at N _R The signal is transmitted continuously for a period T.

Preferably, the B-side receiving antenna calibration unit B' ₂ The state of cycle contraction with T means: b-plane receiving calibration antenna unit at N _T The signal is continuously received for T periods.

Preferably, the A face transmitting antenna calibration unit A' ₁ The state of long hair with T as the cycle means that: a-plane transmitting calibration antenna unit is in N _R The signal is transmitted continuously for a period T.

Preferably, the A-side receiving antenna calibration unit A 'is controlled' ₂ In a state of being long and short with T as a periodThe state means: a-plane receiving calibration antenna unit is in N _T The signal is received continuously for a period T.

Compared with the prior art, the invention has the advantages that:

(1) The invention does not need to carry special calibration equipment in the installation and debugging process, so that the installation and debugging of the equipment in public places such as airports and the like are more convenient and faster, the maintenance and the debugging in the use process of the equipment are more favorably used, and the realization of normalized intermittent calibration operation is more favorably realized.

(2) The invention does not adopt the plate for auxiliary calibration, and the plate for calibration is required to have high flatness, uniformity and smoothness (namely, the microwave is required to reach any point of a plane, and the interaction with the point on the plane is equivalent), which puts high requirements on the production and processing of the plate. And the flat plate is easy to collide in the using process, so that a plurality of pits are formed on the surface. These all contribute to the accuracy of the calibration.

(3) By adopting the calibration method of the horn antenna, the transmitting antenna array signal to be calibrated and the receiving antenna array signal to be calibrated are enabled to interact with the horn antenna, so that the error brought by a calibration piece is reduced to the minimum, and the calibration precision is further improved.

(4) The invention preferably introduces a gradient descent algorithm into the determination process of the position coordinates of the antenna calibration unit, gives the accurate position of the antenna calibration unit, thereby calculating a more accurate phase compensation item, considers the installation errors of 4 calibration antenna units and further improves the calibration precision.

Drawings

FIG. 1 is a schematic view of a calibration device according to the present invention;

FIG. 2 is a schematic structural diagram of the calibration device of the present invention;

FIG. 3 is a flow chart of an extraction calibration method of the calibration device according to the present invention;

fig. 4 is a schematic diagram of the calibration method of the present invention, which is preferably implemented by eight single-pole double-throw switches and is shared by the calibration antenna unit and a middle unit of the original antenna array.

Detailed Description

The invention is described in further detail below with reference to the figures and the specific embodiments.

The invention relates to a calibration device of a circular scanning imaging security inspection system, which comprises: 4 calibration antenna elements and 4 single pole double throw switches; 4 calibration antenna units, namely a B-surface receiving antenna calibration unit, an A-surface receiving antenna calibration unit, a B-surface transmitting antenna calibration unit and an A-surface transmitting antenna calibration unit; the phase errors of the transmitting array channel and the receiving array channel are obtained by adopting the mode that the B-surface receiving antenna calibration unit and the A-surface receiving antenna calibration unit receive the transmitting signals or the B-surface transmitting antenna calibration unit and the A-surface transmitting antenna calibration unit transmit the signals, the phase errors are extracted without carrying special equipment in the installation and debugging process, and the calibration can be completed after the security inspection system is started.

The circular scanning imaging security inspection system is mainly applied to public places such as airport security inspection halls, prison entrances, court entrances and the like. In these public places, particularly airports, often require 24 hours of work, with occasional personnel needing to enter and exit the airport through security checks. The installation of the flat plate is stopped frequently, so that great inconvenience is brought to security inspection.

The security inspection device built in the security inspection imaging system provided by the invention is adopted to finish security inspection, and the calibration of the circular scanning imaging security inspection system can be finished more conveniently, rapidly and accurately.

The invention discloses a circular scanning imaging security check calibration device, which is arranged on a security check system, wherein the security check system is preferably as follows:

the circumference scanning imaging security inspection system comprises a servo motor, an A-surface transmitting and receiving antenna array, a B-surface transmitting and receiving antenna array, an A-surface transmitting antenna calibration unit, an A-surface receiving antenna calibration unit, a B-surface transmitting antenna calibration unit, a B-surface receiving antenna calibration unit, an A-surface transmitting and receiving module, a B-surface transmitting and receiving module, a signal processing module and a display module.

The circle scanning imaging security inspection system firstly controls the A-surface receiving and transmitting antenna array, the B-surface receiving and transmitting antenna array, the A-surface transmitting antenna calibration unit, the A-surface receiving antenna calibration unit, the B-surface transmitting antenna calibration unit and the B-surface receiving antenna calibration unit through a control module in the signal processing module to complete the receiving of calibration signals and the acquisition of calibration parameters. And then the A-surface receiving and transmitting antenna array and the B-surface receiving and transmitting antenna array are controlled to rotate around a rotating shaft as a whole through the servo motor, data acquisition is completed after one rotation, one-time security inspection imaging is completed through an imaging module in the signal processing module after calibration parameters are corrected, and the data is displayed on a display module.

As shown in fig. 1 and fig. 2, a circle scanning imaging security check calibration device based on a probe according to the present invention preferably includes: 4 antenna calibration units and 4 single pole double throw switches;

4 antenna calibration units, namely a B-surface receiving antenna calibration unit, an A-surface receiving antenna calibration unit, a B-surface transmitting antenna calibration unit and an A-surface transmitting antenna calibration unit;

a first single-pole double-throw switch is arranged between the input end (fixed end) of a receiver of the A-side transceiver module, the output end (switching end) of the A-side receiving antenna array and the output end (switching end) of the B-side receiving antenna calibration unit, so that the input end of the receiver of the A-side transceiver module can be connected with the output end of the A-side receiving antenna array and can also be connected with the output end of the B-side receiving antenna calibration unit through a radio frequency cable.

A second single-pole double-throw switch is arranged between the output end (fixed end) of the transmitter of the A-surface transceiver module and the input end (switching end) of the A-surface transmitting antenna array and the input end (switching end) of the B-surface transmitting antenna calibration unit, so that the output end of the transmitter of the A-surface transceiver module can be selectively connected with the input end of the A-surface transmitting antenna array and can also be connected with the input end of the B-surface transmitting antenna calibration unit through a radio frequency cable.

And a third single-pole double-throw switch is arranged between the input end (fixed end) of the receiver of the B-face transceiver module and the output ends (switching ends) of the B-face receiving antenna array and the output end (switching end) of the A-face receiving antenna calibration unit, so that the input end of the receiver of the B-face transceiver module can be connected with the output end of the B-face receiving antenna array and can also be connected with the output end of the A-face receiving antenna calibration unit through a radio frequency cable.

And a fourth single-pole double-throw switch is arranged between the output end (fixed end) of the transmitter of the B-surface transceiver module and the input ends (switching ends) of the B-surface transmitting antenna array and the A-surface transmitting antenna calibration unit, so that the output end of the transmitter of the B-surface transceiver module can be selectively connected with the input end of the B-surface transmitting antenna array and can also be connected with the input end of the A-surface transmitting antenna calibration unit through a radio frequency cable.

Transmitting antenna array B on B surface ₁ Side-mounted B-side transmitting antenna calibration unit B' ₁ Calibration Unit B 'for B-side transmitting antenna' ₁ The A-plane receiving antenna array A is formed by the A-plane receiving antenna array A and the transmitter of the A-plane receiving and transmitting module ₂ The calibration channel of (1);

receiving antenna array B on B side ₂ Side-mounted B-side receiving antenna calibration unit B' ₂ -B-side receive antenna calibration unit B' ₂ The A-surface transmitting antenna array A is formed by the A-surface transmitting antenna array A and the receiver of the A-surface receiving and transmitting module ₁ The calibration channel of (2);

transmitting antenna array A on A surface ₁ An A-side transmitting antenna calibration unit A 'is mounted beside' ₁ A-side transmit antenna calibration unit A' ₁ The B-plane receiving antenna array B is formed by the transmitter of the B-plane transceiver module ₂ The calibration channel of (2);

receiving antenna array A on A surface ₂ Side mounted an A-side receive antenna calibration unit A' ₂ Antenna calibration Unit A 'for A-side reception' ₂ The B-plane transmitting antenna array B is formed by the B-plane transmitting antenna array B and the receiver of the B-plane transmitting-receiving module ₁ The calibration channel of (1);

a-surface transmitting antenna array A ₁ A-side receiving antenna array A ₂ Are jointly arranged on a first plane A; b-surface transmitting antenna array B ₁ B-side receiving antenna array B ₂ Are jointly arranged on a second plane B; the first plane A and the second plane B are arranged oppositely in parallel and can rotate along a rotating shaft under the drive of a servo motor; the rotating shaft is positioned between the first plane A and the second plane B and is parallel to the first plane A and the second plane B, and the rotating shaft is at the same distance with the first plane A and the second plane B.

The A-plane receiving antenna array has N _R A receiving antenna unit; each dayThe receiving period of the line unit is 8 mu s; each receiving antenna unit can be respectively connected with a receiver of the A-surface transceiver module to form a channel as each receiving channel of the A surface;

the A-surface transmitting antenna array has N _T A plurality of transmitting antenna elements; the transmission period of each antenna unit is 8 mu s; each transmitting antenna unit can be respectively connected with a transmitter of the A-surface transceiver module to form a channel as each transmitting channel of the A-surface;

the B-side receiving antenna array has N in total _R A receiving antenna unit; the receiving period of each antenna unit is 8 mus; each receiving antenna unit can be respectively connected with a receiver of the B-surface transceiver module to form a channel as each receiving channel of the B surface;

the B-surface transmitting antenna array has N in total _T A plurality of transmitting antenna elements; the transmission period of each antenna unit is 8 mu s; each transmitting antenna unit can be respectively connected with a transmitter of the B-surface transceiver module to form a channel as each transmitting channel of the B-surface.

Firstly, controlling a first single-pole double-throw switch to connect the output end of an A-side receiving antenna array with the input end of a receiver of an A-side transceiving module, and simultaneously controlling a second single-pole double-throw switch to calibrate a B-side transmitting antenna calibration unit B' ₁ The input end is connected with the output end of the A-surface transceiver module transmitter; controlling the A-surface transmitting antenna array not to work; the B-plane transmitting antenna array does not work; and controlling the A-plane transmitting antenna calibration unit not to work.

Controlling the A-side receiving antenna array to sequentially complete the electrical scanning reception of each unit in the antenna array from top to bottom by taking 8 mu s as a period, and simultaneously controlling the B-side transmitting antenna calibration unit B' ₁ (as shown in FIG. 2) is in a state of long hair with 8 μ s as a period (long hair state, which means that the B-surface transmitting antenna calibration unit continuously transmits signals in 8 μ s period), and N is completed _R After 8 mu s period of operation, each A-side receiving channel finishes receiving B-side transmitting antenna calibration unit B' ₁ Reception of transmitted signals, output N from the receiver of the A-plane Transceiver Module _R Receiving signals, respectively denoted as s _RAi ，i＝1,2,…，N _R ；s _RAi Is the ith path connectedReceiving a signal;

to N _R The method comprises the steps that sampling is carried out on a path of receiving signals respectively, and a plurality of sampling points are obtained after each path of receiving signals are sampled to form a path of discrete signals; (N) _R Receiving a signal to form N _R A path of discrete signals; ) Fourier transform is carried out on each path of discrete signal to obtain each path of signal after Fourier transform, and the maximum value of the amplitude of each path of signal after Fourier transform and the position of a sampling point corresponding to the maximum value are determined _{RA_RANGEmaxi} And phase

Determining the distance between the B-surface transmitting antenna calibration unit and the A-surface receiving antenna array unit according to the position of the B-surface transmitting antenna calibration unit and the position of the ith unit in the A-surface receiving antenna array unit; (thereby determining the position of each unit in the A-plane receiving antenna array unit is different), thereby determining the phase compensation quantity corresponding to each unit in the A-plane receiving antenna array; the phase compensation quantity corresponding to each unit in the A-surface receiving antenna array is used for carrying out phase compensation on the sampling point corresponding to the maximum value of the amplitude of each path of signals after Fourier transform

According to the phase delta 1 of the sampling point corresponding to the maximum value of the amplitude of each path of signal after the Fourier transform after compensation _i (ii) a Phase compensation amount delta 2 corresponding to each path of Fourier transformed signal _i Determining receiver output N of A-plane transceiver module _R Compensation quantity delta 1 of the phase of the received signal _i *Δ2 _i 。

Then, the second single-pole double-throw switch is controlled to send the input end of the A-side transmitting antenna array and the A-side receiving and sending moduleThe transmitter output end is connected and simultaneously controls the first single-pole double-throw switch to calibrate the B-side receiving antenna calibration unit B' ₂ The output end of the antenna is connected with the input end of the A-side transceiver module receiver to control the B-side transmitting antenna array not to work; controlling the A-surface transmitting antenna calibration unit not to work; controlling the calibration unit of the B-surface transmitting antenna not to work;

controlling the A-side transmitting antenna array to sequentially finish transmitting each unit in the antenna array from top to bottom by taking 8 mu s as a period, and simultaneously controlling a B-side receiving antenna calibration unit B' ₂ (as shown in FIG. 2) is in a state of long-time reception (long-time reception, which means that the B-plane emission calibration antenna unit is in N _T Continuously receiving signals for 8 mus period), N is completed _T B-side receive antenna calibration unit B 'after 8 mu s period of operation' ₂ Completing the receiving of the transmitting signals of the units of the A-side transmitting antenna array, and calibrating the unit B 'from the B-side receiving antenna' ₂ Output N _T Receiving signals, respectively denoted as s _TAi ，i＝1,2,…，N _T ；s _TAi Receiving a signal for the ith path;

to N _T The method comprises the steps that a path of received signals are sampled respectively, and a plurality of sampling points are obtained after each path of received signals are sampled to form a path of discrete signals; (N) _T Receiving a signal to form N _T A path of discrete signals; ) Fourier transform is carried out on each path of discrete signal to obtain each path of signal after Fourier transform, and the maximum value of the amplitude of each path of signal after Fourier transform and the position of a sampling point corresponding to the maximum value are determined _{TA_RANGEmaxi} And phase

Determining the distance between the B-surface receiving antenna calibration unit and the A-surface transmitting antenna array unit according to the position of the B-surface receiving antenna calibration unit and the position of the ith unit in the A-surface transmitting antenna array unit; (thereby determining the position of each unit in the A-surface receiving antenna array unit is different), thereby determining the phase compensation quantity corresponding to each unit in the A-surface transmitting antenna array; using the phase compensation quantity corresponding to each unit in the A-surface transmitting antenna array to carry out Fourier transform on each path of maximum signal amplitude value pairPhase of corresponding sampling point

Compensating to obtain the phase delta 3 of the sampling point corresponding to the maximum value of the amplitude of each path of signal after Fourier transform _i ；

According to the sampling point position corresponding to the maximum value of the signal amplitude after each path of Fourier transform _{TA_RANGEmaxi} Determining the phase compensation amount delta 4 corresponding to each path of Fourier transformed signals _i ；

According to the phase delta 3 of the sampling point corresponding to the maximum value of the amplitude of each path of signal after Fourier transform after compensation _i (ii) a Phase compensation amount delta 4 corresponding to each path of Fourier transformed signal _i Determining a compensation quantity delta 3 for the phase of the transmission signal of the transmitter of the A-plane transceiver module _i *Δ4 _i 。

Controlling the third single-pole double-throw switch to connect the output end of the B-side receiving antenna array with the input end of the B-side receiving and transmitting module receiver, and simultaneously controlling the fourth single-pole double-throw switch to connect the input end of the A-side transmitting antenna calibration unit with the output end of the B-side receiving and transmitting module transmitter; controlling the B-plane transmitting antenna array not to work; the A-side transmitting antenna array does not work; the B-surface transmitting antenna calibration unit does not work;

controlling the B-side receiving antenna array to sequentially complete the electrical scanning and receiving of each unit in the antenna array from top to bottom by taking 8 mu s as a period, and simultaneously controlling the A-side transmitting calibration antenna unit A' ₁ (as shown in FIG. 2) is in a state of long hair with 8 μ s as cycle (long hair state, which means that the A-surface emission calibration antenna unit is at N _R Continuously transmitting signals in 8 mus period) to finish N _R After 8 mu s periods of operation, each B-side receive channel completes calibration of the A-side transmit antenna calibration unit A' ₁ Reception of transmitted signals, output N from receiver of B-plane transceiver module _R Receiving signals, respectively denoted as s _RBi ，i＝1,2,…，N _R ；s _RBi Receiving signals for the ith path;

to N _R The received signals are sampled separately to obtain multiple sampling points and form a path of separationScattering signals; (N) _R Receiving a signal to form N _R A path discrete signal; ) Fourier transform is carried out on each path of discrete signals to obtain each path of signals after Fourier transform, and the maximum value of the amplitude of each path of signals after Fourier transform and the sampling point position RB _ RANGE corresponding to the maximum value are determined _maxi And phase

Determining the distance between the A-surface transmitting calibration antenna unit and the B-surface receiving antenna array unit according to the position of the A-surface transmitting antenna calibration unit and the position of the ith unit in the B-surface receiving antenna array unit; (thereby determining the position of each unit in the B-plane receiving antenna array unit is different), thereby determining the phase compensation amount corresponding to each unit in the B-plane receiving antenna array; the phase compensation quantity corresponding to each unit in the B-surface receiving antenna array is used for carrying out Fourier transform on the phase of each path of sampling point corresponding to the maximum value of the signal amplitude

According to the phase delta 5 of the sampling point corresponding to the maximum value of the amplitude of each path of signal after the Fourier transform after compensation _i Phase compensation amount Delta 6 corresponding to each Fourier transformed signal _i Determining receiver output N of B-plane transceiver module _R Compensation quantity delta 5 of received signal phase _i *Δ6 _i 。

Finally, controlling a fourth single-pole double-throw switch to connect the input end of the B-face transmitting antenna array with the output end of a B-face transceiver module transmitter, and simultaneously controlling a third single-pole double-throw switch to connect the output end of an A-face receiving antenna calibration unit with the input end of a B-face transceiver module receiver to control the A-face transmitting antenna array not to work; b, the transmitting antenna array works; the A-surface transmitting antenna calibration unit does not work; the B-surface transmitting antenna calibration unit does not work;

controlling the B-side transmitting antenna array to sequentially finish transmitting each unit in the antenna array from top to bottom by taking 8 mu s as a period, and simultaneously controlling the A-side receiving antenna calibration unit A' ₂ (as shown in FIG. 2) is in a state of long-time reception (long-time reception, which means that the A-plane transmitting calibration antenna unit continuously receives signals in 8 μ s period) with 8 μ s as a period, and N is completed _T After an operation for a period of 8 mus,

a-side receiving antenna calibration unit A' ₂ Completing the receiving of the transmitting signals of the units of the B-side transmitting antenna array, and calibrating the unit A 'from the A-side receiving antenna' ₂ Output N _T The received signals, respectively denoted as s _TBi ，i＝1,2,…，N _T ；s _TBi Receiving signals for the ith path;

to N _T The method comprises the steps that a path of received signals are sampled respectively, and a plurality of sampling points are obtained after each path of received signals are sampled to form a path of discrete signals; (N) _T Receiving a signal to form N _T A path of discrete signals; ) Fourier transform is carried out on each path of discrete signal to obtain each path of signal after Fourier transform, and the maximum value of the amplitude of each path of signal after Fourier transform and the position of a sampling point corresponding to the maximum value are determined _{TB_RANGEmaxi} And phase

Determining the distance between the A-surface receiving antenna calibration unit and the B-surface transmitting antenna array unit according to the position of the A-surface receiving antenna calibration unit and the position of the ith unit in the B-surface transmitting antenna array unit; (thereby determining the position of each unit in the B-surface receiving antenna array unit is different), thereby determining the phase compensation quantity corresponding to each unit in the B-surface transmitting antenna array; the phase compensation quantity corresponding to each unit in the B-surface transmitting antenna array is used for carrying out phase compensation on the sampling point corresponding to the maximum value of the amplitude of each path of signals after Fourier transform

According to the phase delta 7 of the sampling point corresponding to the maximum value of the amplitude of each path of signal after the compensation and the Fourier transform _i (ii) a Phase compensation amount delta 8 corresponding to each path of Fourier transformed signal _i Determining the compensation quantity Delta 7 of the phase of the transmission signal of the transmitter of the B-plane transceiver module _i *Δ8 _i 。

Output N of receiver of A-plane transceiver module _R Compensation RA for the phase of the received signal _compensate N of transmitter output of A-plane transceiver module _T Compensation TA of phase of channel transmitting signal _compensate Receiver output N of B-side transceiver module _R Compensation RB for the phase of the received signal _compensate And N of transmitter output of B-plane transceiver module _T Compensation quantity TB of road transmitting signal phase _compensate The storage is carried out, the basic function of the calibration device of the circular scanning imaging security inspection system is realized, and the precision of the calibration data is improved. A flow chart for extracting calibration parameters is shown in figure 3,

in the circular scanning imaging security check calibration device, the receiver output N of the A-surface transceiver module can be further stored _R Compensation RA for the phase of the received signal _compensate N of transmitter output of A-plane transceiver module _T Compensation TA of phase of channel transmitting signal _compensate Receiver output N of B-side transceiver module _R Compensation RB for the phase of the received signal _compensate And N of transmitter output of B-plane transceiver module _T Compensation quantity TB of road transmitting signal phase _compensate The preferred embodiment of the calibration is as follows:

firstly, controlling a security inspection imaging system to work in an imaging mode, namely controlling a first single-pole double-throw switch to connect the output end of an A-side receiving antenna array with the input end of a receiver of an A-side transceiver module, and simultaneously controlling a second single-pole double-throw switch to connect the input end of an A-side transmitting antenna array with the output end of a transmitter of the A-side transceiver module; simultaneously controlling a third single-pole double-throw switch to connect the output end of a B-face receiving antenna array with the input end of a receiver of a B-face transceiving module, and simultaneously controlling a fourth single-pole double-throw switch to connect the input end of a B-face transmitting antenna array with the output end of a transmitter of the B-face transceiving module;

when a person to be detected enters between a first plane A and a second plane B, the rotating shaft is controlled to rotate for N degrees (the preferable value range of N degrees is 90-120 degrees), each unit in the A-plane transmitting antenna array finishes signal transmission from top to bottom for each rotating angle, the person to be detected is scanned, after the person to be detected is reflected, each unit in the A-plane receiving antenna array finishes signal reception from top to bottom and is sent to the input end of the receiver of the A-plane transceiver module, and the output end of the receiver of the A-plane transceiver module outputs N x N of the A-plane _R An echo signal; by using a 1 _i *Δ2 _i And Δ 3 _i *Δ4 _i For face A N _R Phase compensation is carried out on the echo signals to obtain echo signals after A-surface calibration is finished; the inversion of the image of the detected person is completed through a wave number domain imaging algorithm, so that the coherence of signals is further improved, and the definition and the focusing effect of the image are further improved.

Aiming at each rotation angle, each unit in the B-surface transmitting antenna array finishes signal transmission from top to bottom, a detected person is scanned, after the signal is reflected by the detected person, each unit in the B-surface receiving antenna array finishes signal reception from top to bottom and is sent to the input end of a receiver of the B-surface transceiver module, and the output end of the receiver of the B-surface transceiver module outputs the N of the B surface _R An echo signal; by using a.DELTA.5 _i *Δ6 _i And Δ 7 _i *Δ8 _i N x N to face B _R Phase compensation is carried out on the echo signals to obtain B-surface echo signals after calibration, inversion of the image of the detected person is completed through a wavenumber domain imaging algorithm, and coherence of the signals is further improved, so that definition and focusing effect of the image are improved.

The preferred embodiment (example 1) is: establishing an oxyz coordinate system, wherein the origin is the center of the A-surface receiving antenna array, the arrangement direction of receiving antenna units in the A-surface receiving antenna array is the y-axis direction, the X-axis is orthogonal to the y-axis, and the X-axis direction is the direction of the center pointing to the rotating shaft of the A-surface receiving antenna array; determining a Z axis according to a right hand rule; the Z axis is positioned in a first plane A;

the position coordinate of the ith unit in the A-plane receiving antenna array in an oxyz coordinate system is assumed to be (R) _Axi ,R _Ayi ,R _Azi ),i＝1,2,…，N _R ；

R _Axi The X-axis coordinate of the ith unit in the A-plane receiving antenna array unit in an oxyz coordinate system is represented; r is _Ayi The y-axis coordinate of the ith unit in the A-plane receiving antenna array unit in an oxyz coordinate system is represented; r is _Azi The z-axis coordinate of the ith unit in the A-plane receiving antenna array unit under an oxyz coordinate system is represented;

position B 'of B-side transmitting calibration antenna unit in oxy z coordinate system' ₁ Is (T) _Bx’ ,T _By' ,T _Bz' )；T _Bx' Representing the x-axis coordinate of the B-surface emission calibration antenna unit in an oxyz coordinate system; t is a unit of _By' Representing the y-axis coordinate of the B-plane transmitting calibration antenna unit in an oxyz coordinate system; t is _Bz' Representing the z-axis coordinate of the B-plane emission calibration antenna unit in an oxyz coordinate system;

then under the oxyz coordinate system, the distance R between the position of the ith unit in the A-plane receiving antenna array and the position of the B-plane transmitting calibration antenna unit ₁ Expressed as follows:

the receiver output N of the a-plane transceiver module _R The first phase compensation term of the phase of the received signal is

Wherein k is _c Is the system center wavenumber.

Receiver output N of A-plane transceiver module _R The phase of the received signal is the second phase compensation term

Wherein _f Is the operating frequency of the system.

Receiver output N of A-plane transceiver module _R Compensation RA for the phase of the received signal _compensate

RA _compensate ＝Δ1 _i ×Δ2 _i ；

Suppose the position coordinate of the ith unit in the A-plane transmitting antenna array in the oxyz coordinate system is (T) _Axi ,T _Ayi ,T _Azi ),i＝1,2,…，N _T ；

T _Axi The X-axis coordinate of the ith unit in the A-plane receiving antenna array unit in an oxyz coordinate system is represented; t is _Ayi The y-axis coordinate of the ith unit in the A-plane receiving antenna array unit in an oxyz coordinate system is represented; t is _Azi The z-axis coordinate of the ith unit in the A-plane receiving antenna array unit in an oxyz coordinate system is represented;

position B 'of B-side receiving calibration antenna unit in oxy z coordinate system' ₁ Is (R) _Bx' ,R _By' ,R _Bz' )；R _Bx' Representing the x-axis coordinate of the B-surface receiving calibration antenna unit in an oxyz coordinate system; r _By' Representing the y-axis coordinate of the B-plane receiving calibration antenna unit in an oxyz coordinate system; r _Bz' The z-axis coordinate of the B-plane receiving calibration antenna unit under an oxyz coordinate system is represented;

then under the oxyz coordinate system, the distance R between the position of the ith unit in the A-plane transmitting antenna array and the position of the B-plane receiving calibration antenna unit ₂ Expressed as follows:

the transmitter output N of the a-plane transceiver module _T The first phase compensation term of the phase of the received signal is

Wherein k is _c Is the system center wavenumber.

Receiver output N of A-plane transceiver module _T The second phase compensation term of the phase of the received signal is

Wherein _f Is the operating frequency of the system.

Transmitter output N of a-plane transceiver module _T Compensation TA of the phase of the received signal _compensate

TA _compensate ＝Δ3 _i ×Δ4 _i ；

The position coordinate of the ith unit in the B-surface receiving antenna array in an oxyz coordinate system is assumed to be (R) _Bxi ,R _Byi ,R _Bzi ),i＝1,2,…，N _R ；

R _Bxi The X-axis coordinate of the ith unit in the B-plane receiving antenna array unit in an oxyz coordinate system is represented; r _Byi The y-axis coordinate of the ith unit in the B-plane receiving antenna array unit in an oxyz coordinate system is represented; r _Bzi The z-axis coordinate of the ith unit in the B-plane receiving antenna array unit in an oxyz coordinate system is represented;

position A 'of A-side emission calibration antenna unit in oxy z coordinate system' ₁ Is (T) _Ax' ,T _Ay' ,T _Az' )；T _Ax' Representing the x-axis coordinate of the A-surface emission calibration antenna unit in an oxyz coordinate system; t is a unit of _Ay' Representing the y-axis coordinate of the A-surface emission calibration antenna unit in an oxyz coordinate system; t is _Az' The z-axis coordinate of the A-plane transmitting calibration antenna unit under an oxyz coordinate system is represented;

then under the oxyz coordinate system, the distance R between the position of the ith unit in the B-surface receiving antenna array and the position of the A-surface transmitting calibration antenna unit ₃ Expressed as follows:

the receiver output N of the B-plane transceiver module _R The first phase compensation term of the phase of the received signal is

Wherein k is _c Is the system center wavenumber.

Receiver output N of B-plane transceiver module _R The second phase compensation term of the phase of the received signal is

Wherein _f Is the operating frequency of the system.

Receiver output N of B-plane transceiver module _R Compensation RB for the phase of the received signal _compensate

RB _compensate ＝Δ5 _i ×Δ6 _i ；

Suppose the position coordinate of the ith unit in the B-surface transmitting antenna array in the oxyz coordinate system is (T) _Bxi ,T _Byi ,T _Bzi ),i＝1,2,…，N _T ；

T _Bxi The X-axis coordinate of the ith unit in the B-plane receiving antenna array unit in an oxyz coordinate system is represented; t is _Byi The y-axis coordinate of the ith unit in the B-plane receiving antenna array unit in an oxyz coordinate system is represented; t is _Bzi The z-axis coordinate of the ith unit in the B-plane receiving antenna array unit in an oxyz coordinate system is represented;

position A 'of A-side receiving calibration antenna unit in oxyz coordinate system' ₂ Is (R) _Ax' ,R _Ay' ,R _Az' )；R _Ax' The coordinate of the A-surface receiving calibration antenna unit on the x axis under an oxyz coordinate system is represented; r _Ay' Representing the y-axis coordinate of the A-surface receiving calibration antenna unit in an oxyz coordinate system; r _Az' The z-axis coordinate of the A-plane receiving calibration antenna unit under an oxyz coordinate system is represented;

under the oxyz coordinate system, the distance R between the position of the ith unit in the B-surface transmitting antenna array and the position of the A-surface receiving calibration antenna unit ₄ Expressed as follows:

the transmitter output N of the B-plane transceiver module _T The first phase compensation term of the phase of the received signal is

Wherein k is _c The system center wavenumber.

Wherein _f Is the operating frequency of the system.

Transmitter output N of A-plane transceiver module _T Compensation quantity TB of path receiving signal phase _compensate

TB _compensate ＝Δ7 _i ×Δ8 _i ；

As shown in fig. 3, as described above, the acquisition of calibration data of the a-plane receiving channel is completed respectively; completing the extraction and storage of calibration parameters of the A-plane receiving channel; completing the acquisition of calibration data of the A-surface emission channel; finishing the extraction and storage of calibration parameters of the A-surface emission channel; completing the acquisition of calibration data of a B-surface receiving channel; completing the extraction and storage of calibration parameters of a B-surface receiving channel; completing the acquisition of calibration data of a B-surface emission channel; finishing the extraction and storage of calibration parameters of the B-plane emission channel; and finishing the extraction of the channel inconsistency parameters.

Controlling the security inspection system to work in an imaging mode and respectively obtaining the A surface and the B surface N x N of the inspected person _R An echo signal; by RA _compensate And TA _compensate For face A N _R Phase compensation is carried out on the echo signals to obtain calibrated A-plane echo signals, inversion of the detected person image is completed through a wave number domain imaging algorithm, and the coherence of the signals is further improved so that the definition and the focusing effect of the image are improved. Simultaneous adoption of RB _compensate And TB _compensate For face B N _R Phase compensation is carried out on the echo signals to obtain B-surface echo signals after calibration, inversion of the detected person image is completed through a wave number domain imaging algorithm, and the coherence of the signals is further improved so that the definition and the focusing effect of the image are improved.

The further preferred scheme is as follows: as shown in fig. 4, the calibration is done using eight single pole double throw switches and the calibration antenna element is common to the middle of the original antenna array. One transmitting unit in the middle position of the A-side transmitting array is used as an A-side transmitting antenna calibration unit A' ₁ One receiving unit at the middle position of the A-side receiving array is used as an A-side receiving antenna calibration unit A' ₂ One transmitting unit at the middle position of the B-side transmitting array serves as a B-side transmitting antenna calibration unit B' ₁ And one receiving unit at the middle position of the B-side receiving array is used as a B-side receiving antenna calibration unit B' ₂ ；

Similarly, A-side transmitting antenna calibration unit A' ₁ Antenna calibration Unit A 'for A-side reception' ₂ Calibration Unit B 'for B-side transmitting antenna' ₁ And a B-side receiving antenna calibration unit B' ₂ Respectively connected with A-surface receiving/transmitting antenna array, B-surface receiving/transmitting antenna array, A-surface transmitting antenna calibration unit, A-surface receiving antenna calibration unit, B-surface transmitting antenna calibration unit and B-surface receiving antenna calibration unit in the security inspection system through a plurality of single-pole double-throw switches, and then obtaining a signal s for extracting calibration parameters of the A-surface receiving antenna array _RAi ，i＝1,2,…，N _R (ii) a Signal s for extracting calibration parameters of A-plane transmitting antenna array _TAi ，i＝1,2,…，N _T (ii) a Signal s for extracting calibration parameters of B-plane receiving antenna array _RBi ，i＝1,2,…，N _R (ii) a Signal s for extracting calibration parameters of B-plane transmitting antenna array _TBi ，i＝1,2,…，N _T . Otherwise, the same procedure as in example 1 was followed.

The invention does not need to carry special calibration equipment in the installation and debugging process, so that the installation and debugging of the equipment in public places such as airports and the like are more convenient and faster, the maintenance and the debugging in the use process of the equipment are more favorably used, and the realization of normalized intermittent calibration operation is more favorably realized.

The invention does not adopt a panel for auxiliary calibration, and the panel for calibration is required to have high flatness, uniformity and smoothness (namely, the microwave is required to reach any point of the plane, the interaction between the plane and the point is equivalent, which puts high requirements on the production and processing of the panel.

The invention introduces the gradient descent algorithm into the determination process of the position coordinates of the antenna calibration unit and gives the accurate position of the antenna calibration unit, thereby calculating a more accurate phase compensation item and further improving the calibration precision.

The invention realizes the further proposal of improving the calibration precision: the absolute position of the calibration antenna is generally determined by means of optical scanning and the like, and the method has the disadvantages of needing a special instrument, being complex to operate, having slow measuring speed and being not suitable for application in public places. The invention solves the accurate position of the calibration antenna through a gradient descent algorithm, so that the position measurement is more accurate and more convenient. The specific method for solving and calibrating the accurate position of the antenna unit by the gradient descent method is as follows:

taking the determination of the position coordinates of the B-plane transmitting antenna calibration unit as an example:

first, an objective function TAR is determined _RA ：

Wherein delay ₁ The internal delay of the system is also because the A-plane receiving antenna array is a column vector, R _Axi ＝R _Ax0 ，R _Azi ＝R _Az0 ，R _Ax0 And R _Az0 Is a constant. The above formula is rewritten as:

for T in the above formula _Bx' 、T _By' 、T _Bz' And delay ₁ The deviation is calculated as follows:

T′ _Bx' ＝αT _Bx'

T′ _By' ＝αT _By'

T′ _Bz' ＝αT _Bz'

delay′＝αdelay ₁

in the above formula _α Is an infinitesimal quantity, T' _Bx' 、T′ _By' 、T′ _Bz' And delay' ₁ And calibrating the unit coordinates for the updated B-plane transmitting antenna. The partial derivation operation is repeated NN times, NN is more than or equal to 1000 times, and therefore one optimal solution, T' _Bx' 、T′ _By' 、T′ _Bz' And delay' ₁ . Prepared from T' _Bx' 、T′ _By' 、T′ _Bz' And the process of extracting the calibration parameters of the A-surface receiving antenna array is carried in, so that more accurate calibration parameters of the A-surface receiving antenna array can be obtained.

The position coordinates of the B-plane receiving antenna calibration unit can be obtained in the same way:

first, an objective function TAR is determined _TA ：

Wherein delay ₂ The internal delay of the system is realized, and T is realized because the A-plane transmitting antenna array is a column vector _Axi ＝T _Ax0 ，T _Azi ＝T _Az0 ，T _Ax0 And T _Az0 Is a constant. The above formula is rewritten as:

for R in the above formula _Bx' 、R _By' 、R _Bz' And delay ₂ The deviation is calculated as follows:

R′ _Bx' ＝αR _Bx'

R′ _By' ＝αR _By'

R′ _Bz' ＝αR _Bz'

delay′ ₂ ＝αdelay ₂

in the above formula, alpha is an infinitesimal quantity, R' _Bx' 、R′ _By' 、R′ _Bz' And delay' ₂ The cell coordinates are calibrated for the updated B-plane receive antenna. The partial derivation operation is repeated NN times, NN is more than or equal to 1000 times, and therefore one optimal solution, R' _Bx' 、R′ _By' 、R′ _Bz' And delay' ₂ . R' _Bx' 、R′ _By' 、R′ _Bz' And the process of extracting the calibration parameters of the A-surface transmitting antenna array is carried in, so that more accurate calibration parameters of the A-surface transmitting antenna array can be obtained.

The position coordinates of the A-plane transmitting antenna calibration unit can be obtained by the same method:

first, an objective function TAR is determined _RB ：

Wherein delay ₃ The internal delay of the system is determined, and R is determined because the B-plane receiving antenna array is a column vector _Bxi ＝R _Bx0 ，R _Bzi ＝R _Bz0 ，R _Bx0 And R _Bz0 Is a constant. The above formula is rewritten as:

for T in the above formula _Ax' 、T _Ay' 、T _Az' And delay ₃ The deviation is calculated as follows:

T′ _Ax' ＝αT _Ax'

T′ _Ay' ＝αT _Ay'

T′ _Az' ＝αT _Az'

delay′＝αdelay ₃

in the above formula, alpha is an infinitesimal quantity, T' _Ax' 、T′ _Ay' 、T′ _Az' And delay' ₃ And calibrating the unit coordinates for the updated A-plane transmitting antenna. The partial derivation operation is repeated NN times, NN is more than or equal to 1000 times, and therefore one optimal solution, T' _Ax' 、T′ _Ay' 、T′ _Az' And delay' ₃ . Mixing T' _Ax' 、T′ _Ay' 、T′ _Az' And bringing the calibration parameter extraction process of the B-side receiving antenna array into the process, thereby obtaining more accurate calibration parameters of the B-side receiving antenna array.

In the same way, the position coordinates of the calibration unit of the A-plane receiving antenna can be obtained:

first, an objective function TAR is determined _TB ：

Wherein delay ₄ Is the internal delay of the system, and because the B-plane transmitting antenna array is a column vector, T is _Bxi ＝T _Bx0 ，T _Bzi ＝T _Bz0 ，T _Bx0 And T _Bz0 Is a constant. The above formula is rewritten as:

to R in the above formula _Ax' 、R _Ay' 、R _Az' And delay ₄ The deviation is calculated as follows:

R′ _Ax' ＝αR _Ax'

R′ _Ay' ＝αR _Ay'

R′ _Az' ＝αR _Az'

delay′ ₄ ＝αdelay ₄

in the above formula, alpha is an infinitesimal quantity, R' _Ax' 、R′ _Ay' 、R′ _Az' And delay' ₄ The updated calibration antenna coordinates. The partial derivation operation is repeated NN times, NN is more than or equal to 1000 times, and therefore one optimal solution, R' _Ax' 、R′ _Ay' 、R′ _Az' And delay' ₄ . R' _Ax' 、R′ _Ay' 、R′ _Az' And bringing the calibration parameter extraction process of the B-surface transmitting antenna array into the process, thereby obtaining more accurate calibration parameters of the B-surface transmitting antenna array.

The calibration parameters were used as in example 1.

The invention does not adopt the plate for auxiliary calibration, and the plate for calibration is required to have high flatness, uniformity and smoothness (namely, the microwave is required to reach any point of a plane, and the interaction with the point on the plane is equivalent), which puts high requirements on the production and processing of the plate. And the flat plate is easy to collide in the using process, so that a plurality of pits are formed on the surface. These all contribute to the accuracy of the calibration.

According to the invention, through adopting the calibration method of the horn antenna, the transmitting antenna array signal to be calibrated and the receiving antenna array signal to be calibrated are enabled to interact with the horn antenna, so that the error caused by a calibration piece is minimized, and the calibration precision is further improved.

Claims

1. A circle scanning imaging security check calibrating device is characterized by comprising: 4 antenna calibration units and 4 single-pole double-throw switches;

a first single-pole double-throw switch is arranged between the input end of the receiver of the A-side transceiver module and the output ends of the A-side receiving antenna array and the B-side receiving antenna calibration unit, so that the input end of the receiver of the A-side transceiver module can be connected with the output end of the A-side receiving antenna array and also can be connected with the output end of the B-side receiving antenna calibration unit through a radio frequency cable;

a second single-pole double-throw switch is arranged between the output end of the transmitter of the A-surface transceiver module and the input ends of the A-surface transmitting antenna array and the B-surface transmitting antenna calibration unit, so that the output end of the transmitter of the A-surface transceiver module can be selectively connected with the input end of the A-surface transmitting antenna array and can also be connected with the input end of the B-surface transmitting antenna calibration unit through a radio frequency cable;

a third single-pole double-throw switch is arranged between the input end of the receiver of the B-side transceiver module and the output ends of the B-side receiving antenna array and the A-side receiving antenna calibration unit, so that the input end of the receiver of the B-side transceiver module can be connected with the output end of the B-side receiving antenna array and can also be connected with the output end of the A-side receiving antenna calibration unit through a radio frequency cable;

a fourth single-pole double-throw switch is arranged between the output end of the transmitter of the B-surface transceiver module and the input ends of the B-surface transmitting antenna array and the A-surface transmitting antenna calibration unit, so that the output end of the transmitter of the B-surface transceiver module can be selectively connected with the input end of the B-surface transmitting antenna array and can also be connected with the input end of the A-surface transmitting antenna calibration unit through a radio frequency cable;

transmitting antenna array B on B surface ₁ A B-surface transmitting antenna calibration unit is arranged beside

B-surface transmitting antenna calibration unit

The A-plane receiving antenna array A is formed by the A-plane receiving antenna array A and the transmitter of the A-plane receiving and transmitting module ₂ The calibration channel of (1);

receiving antenna array B on B side ₂ A B-surface receiving antenna calibration unit is arranged beside

B-plane receiving antenna calibration unit

The A-surface transmitting antenna array A is formed by the A-surface transmitting antenna array A and the receiver of the A-surface receiving and transmitting module ₁ The calibration channel of (1);

transmitting antenna array A on A surface ₁ Side-mounted A-surface transmitting antenna calibration unit

A-surface transmitting antenna calibration unit

The B-plane receiving antenna array B is formed by the B-plane receiving antenna array B and the transmitter of the B-plane receiving and transmitting module ₂ The calibration channel of (2);

receiving antenna array A on A surface ₂ A-surface receiving antenna calibration unit is arranged beside

A-plane receiving antenna calibration unit

The B-plane transmitting antenna array B is formed by the B-plane transmitting antenna array B and the receiver of the B-plane transmitting-receiving module ₁ The calibration channel of (2);

a-surface transmitting antenna array A ₁ A-side receiving antenna array A ₂ The first plane A and the second plane A are jointly arranged, and the A plane is marked; b-surface transmitting antenna array B ₁ B-side receiving antenna array B ₂ The two planes are jointly arranged on a second plane B, and the plane B is marked; the first plane A and the second plane B are oppositely arranged in parallel and can rotate along the rotating shaft under the drive of the servo motor; the rotating shaft is positioned between the first plane A and the second plane B and is parallel to the first plane A and the second plane B, and the distance between the rotating shaft and the first plane A is the same as that between the rotating shaft and the second plane B;

the A-plane receiving antenna array has N _R A receiving antenna unit; the receiving period of each antenna unit is T; each receiving antenna unit can be respectively connected with a receiver of the A-surface transceiver module to form a channel as each receiving channel of the A surface;

the B-side receiving antenna array has N in total _R A receiving antenna unit; the receiving period of each antenna unit is T; each receiving antenna unit can be respectively connected with a receiver of the B-surface transceiver module, and a channel is formed as each receiving channel of the B surface;

the B-surface transmitting antenna array has N in total _T A plurality of transmitting antenna elements; the transmission period of each antenna unit is T; each transmitting antenna unit can be respectively connected with the transmitter of the B-plane transceiver moduleConnecting to form a channel as each emission channel of the B surface;

controlling the first single-pole double-throw switch to connect the output end of the A-side receiving antenna array with the input end of the receiver of the A-side receiving-transmitting module, and controlling the second single-pole double-throw switch to calibrate the B-side transmitting antenna

The input end is connected with the output end of the transmitter of the A-side transceiver module; controlling the A-surface transmitting antenna array not to work; the B-plane transmitting antenna array does not work; the A-surface transmitting antenna calibration unit does not work;

controlling the A-surface receiving antenna array to complete the electric scanning of each unit in the antenna array from top to bottom in sequence by taking T as a period, and simultaneously controlling the B-surface transmitting antenna calibration unit

In long-hair state with T as period to complete N _R After the work of each period T, each receiving channel of the A surface finishes calibrating the B surface transmitting antenna

Reception of transmitted signals, output N from the receiver of the A-plane Transceiver Module _R Receiving signals, respectively denoted as s _RAi ，i＝1,2,…,N _R ；s _RAi Receiving signals for the ith path;

to N _R The method comprises the steps that a path of received signals are sampled respectively, and a plurality of sampling points are obtained after each path of received signals are sampled to form a path of discrete signals; fourier transform is carried out on each path of discrete signal to obtain each path of signal after Fourier transform, and the maximum value of the amplitude of each path of signal after Fourier transform and the sampling point position RA _ RANGE corresponding to the maximum value are determined _maxi And phase

According to the position of the B-surface transmitting antenna calibration unit and the position of the ith unit in the A-surface receiving antenna array unit,determining the distance between a B-surface transmitting antenna calibration unit and an A-surface receiving antenna array unit so as to determine the phase compensation amount corresponding to each unit in the A-surface receiving antenna array; the phase compensation quantity corresponding to each unit in the A-surface receiving antenna array is used for carrying out phase compensation on the sampling point corresponding to the maximum value of the amplitude of each path of signals after Fourier transform

According to the sampling point position RA _ RANGE corresponding to the maximum value of the signal amplitude after each path of Fourier transform _maxi Determining the phase compensation amount delta 2 corresponding to each path of Fourier transformed signals _i ；

According to the phase delta 1 of the sampling point corresponding to the maximum value of the amplitude of each path of signal after Fourier transform after compensation _i (ii) a Phase compensation amount delta 2 corresponding to each Fourier-transformed signal _i Determining receiver output N of A-plane transceiver module _R Compensation RA for the phase of the received signal _compensate ；

Secondly, controlling a second single-pole double-throw switch to connect the input end of the A-side transmitting antenna array with the output end of the transmitter of the A-side receiving and transmitting module, and simultaneously controlling a first single-pole double-throw switch to calibrate the B-side receiving antenna

The output end of the antenna is connected with the input end of a receiver of the A-side transceiver module to control the B-side transmitting antenna array to not work; the B-surface transmitting antenna calibration unit does not work; the A-surface transmitting antenna calibration unit does not work;

controlling the A-surface transmitting antenna array to finish the transmission of each unit in the antenna array from top to bottom in sequence by taking T as a period, and simultaneously controlling the B-surface receiving antenna calibration unit

In the state of taking T as cycle length to finish N _T Operation of one period TRear, B-plane receiving antenna calibration unit

Completing the receiving of the transmitting signals of the units of the A-surface transmitting antenna array, and calibrating the units from the B-surface receiving antenna

Output N _T Receiving signals, respectively denoted as s _TAi ，i＝1,2,…,N _T ；s _TAi Receiving a signal for the ith path;

Determining the distance between the B-surface receiving antenna calibration unit and the A-surface transmitting antenna array unit according to the position of the B-surface receiving antenna calibration unit and the position of the ith unit in the A-surface transmitting antenna array unit, thereby determining the phase compensation amount corresponding to each unit in the A-surface transmitting antenna array; the phase compensation quantity corresponding to each unit in the A-surface transmitting antenna array is used for carrying out phase compensation on the sampling point corresponding to the maximum value of the amplitude of each path of signals after Fourier transform

According to the sampling point position TA _ RANGE corresponding to the maximum value of the signal amplitude after each path of Fourier transform _maxi Determining the phase compensation amount delta 4 corresponding to each path of Fourier transformed signals _i ；

According to each path after compensationPhase delta 3 of sampling point corresponding to maximum value of signal amplitude after Fourier transform _i (ii) a Phase compensation amount delta 4 corresponding to each Fourier transformed signal _i Determining N of transmitter output of A-plane transceiver module _T Compensation TA of phase of channel transmitting signal _compensate ；

Controlling a third single-pole double-throw switch to connect the output end of the B-side receiving antenna array with the input end of a receiver of the B-side receiving and transmitting module, and simultaneously controlling a fourth single-pole double-throw switch to connect the input end of the A-side transmitting antenna calibration unit with the output end of a transmitter of the B-side receiving and transmitting module; controlling the B-surface transmitting antenna array not to work; the A-side transmitting antenna array does not work; b, the transmitting antenna calibration unit works;

controlling the B-surface receiving antenna array to complete the electric scanning reception of each unit in the antenna array from top to bottom in sequence by taking T as a period, and simultaneously controlling the A-surface transmitting antenna calibration unit

In the state of long hair with 8 mus as period, N is completed _R After 8 mu s period work, each receiving channel of the B surface finishes calibrating the A surface transmitting antenna

Reception of the transmitted signal, output N from the receiver of the B-plane Transceiver Module _R The received signals, respectively denoted as s _RBi ，i＝1,2,…,N _R ；s _RBi Receiving a signal for the ith path;

to N _R Respectively sampling the received signals, obtaining a plurality of sampling points after each received signal is sampled to form a path of discrete signal, carrying out Fourier transform on each path of discrete signal to obtain signals after each path of Fourier transform, and determining the maximum value of the amplitude of each path of signals after Fourier transform and the sampling point position RB _ RANGE corresponding to the maximum value _maxi And phase

Calibrating a transmitting antenna according to the A-planeDetermining the distance between the calibration unit of the A-surface transmitting antenna and the array unit of the B-surface receiving antenna according to the position of the quasi-unit and the position of the ith unit in the array unit of the B-surface receiving antenna, thereby determining the phase compensation amount corresponding to each unit in the array unit of the B-surface receiving antenna; the phase compensation quantity corresponding to each unit in the B-surface receiving antenna array is used for carrying out Fourier transform on the phase of each path of sampling point corresponding to the maximum value of the signal amplitude

Finally, controlling a fourth single-pole double-throw switch to connect the input end of the B-face transmitting antenna array with the output end of the transmitter of the B-face receiving and transmitting module, and simultaneously controlling a third single-pole double-throw switch to connect the input end of the A-face receiving antenna calibration unit with the output end of the receiver of the B-face receiving and transmitting module, and controlling the A-face transmitting antenna array not to work; the B-surface transmitting antenna calibration unit does not work; the A-surface transmitting antenna calibration unit does not work;

controlling the B-surface transmitting antenna array to finish the transmission of each unit in the antenna array from top to bottom in sequence by taking T as a period, and simultaneously controlling the A-surface receiving antenna calibration unit

In the state of taking T as cycle length to finish N _T After T period of work, A-plane receiving antenna calibration unit

Completing the receiving of the transmitted signals of the units of the B-surface transmitting antenna array, and calibrating the units from the A-surface receiving antenna

Output N _T Receiving signals, respectively denoted as s _TBi ，i＝1,2,…,N _T ；s _TBi Receiving a signal for the ith path;

to N _T Respectively sampling the received signals, obtaining a plurality of sampling points after sampling each received signal to form a discrete signal, carrying out Fourier transform on each discrete signal to obtain signals after Fourier transform, and determining the maximum value of the amplitude of each signal after Fourier transform and the sampling point position TB _ RANGE corresponding to the maximum value _maxi And phase

Determining the distance between the A-surface receiving antenna calibration unit and the B-surface transmitting antenna array unit according to the position of the A-surface receiving antenna calibration unit and the position of the ith unit in the B-surface transmitting antenna array unit, thereby determining the phase compensation amount corresponding to each unit in the B-surface transmitting antenna array; the phase compensation quantity corresponding to each unit in the B-surface transmitting antenna array is used for carrying out phase compensation on the sampling point corresponding to the maximum value of the amplitude of each path of signals after Fourier transform

According to the sampling point position TB _ RANGE corresponding to the maximum value of the signal amplitude after each path of Fourier transform _maxi Determining the phase compensation amount delta 8 corresponding to each path of Fourier transformed signals _i ；

According to the phase delta of the sampling point corresponding to the maximum value of the amplitude of each path of signal after the compensation and the Fourier transform7 _i (ii) a Phase compensation amount delta 8 corresponding to each path of Fourier transformed signal _i Determining N of transmitter output of B-plane transceiver module _T Compensation quantity TB of road transmitting signal phase _compensate ；

Output N of receiver of A-plane transceiver module _R Compensation RA for the phase of the received signal _compensate N of transmitter output of A-plane transceiver module _T Compensation TA of phase of channel transmitting signal _compensate Receiver output N of B-side transceiver module _R Compensation RB for the phase of the received signal _compensate And N of transmitter output of B-plane transceiver module _T Compensation quantity TB of road transmitting signal phase _compensate And storing.

2. The circular scanning imaging security check calibration device of claim 1, wherein: receiver output N of A-plane transceiver module _R Compensation RA for the phase of the received signal _compensate ＝Δ1 _i *Δ2 _i 。

3. The circular scanning imaging security inspection calibration device of claim 1, wherein: n of transmitter output of A-plane transceiver module _T Compensation TA of phase of channel transmitting signal _compensate ＝Δ3 _i *Δ4 _i 。

4. The circular scanning imaging security check calibration device of claim 1, wherein: receiver output N of B-plane transceiver module _R Compensation RB for the phase of the received signal _compensate ＝Δ5 _i *Δ6 _i 。

5. The circular scanning imaging security inspection calibration device of claim 1, wherein: n of transmitter output of B-plane transceiver module _T Compensation quantity TB of road transmitting signal phase _compensate ＝Δ7 _i *Δ8 _i 。

6. The circular scanning imaging security check calibration device of claim 1, wherein: t is 8. Mu.s.

7. The circular scanning imaging security inspection calibration device of claim 1, wherein: b-surface transmitting antenna calibration unit

The state of long hair with T as the cycle means that: b-plane transmitting antenna calibration unit is in N _R The signal is transmitted continuously for a period T.

8. The circular scanning imaging security inspection calibration device of claim 1, wherein: b-plane receiving antenna calibration unit

The state of being long and short with T is as follows: b-plane receiving antenna calibration unit at N _T The signal is continuously received for T periods.

9. The circular scanning imaging security check calibration device of claim 1, wherein: a-surface transmitting antenna calibration unit

The state of long hair with T as the cycle means that: a-plane transmitting antenna calibration unit is in N _R The signal is continuously transmitted for a period T.