阅读说明：本技术 一种用于收发双工相控阵天线的内校准系统及方法 (Internal calibration system and method for transmitting-receiving duplex phased array antenna ) 是由 张宙 马立波 金建忠 刘岩 白杨 刘彦丹 冯昊程 韩国栋 赵楠 于 2020-06-29 设计创作，主要内容包括：本发明公开了一种用于收发双工相控阵天线的内校准系统及方法,属于相控阵天线技术领域。该系统包括定标分机、波控分机、接收/发射定标网络组合、接收/发射馈电网络组合、耦合器和接收/发射通道。本发明通过耦合器将定标分机内产生的单载波信号在整个系统内形成信号回路,将携带有通道幅相信息的信号回传到定标分机,在定标分机内实现信号幅相信息的解算,再将通道幅相信息通过波控分机补偿到相控阵各有源通道,从而实现相控阵天线的幅相标定。本系统的组成部分均为相控阵天线的主要组成部分,不需借助外部设备即可实现相控阵天线的快速校准。(The invention discloses an internal calibration system and method for a transceiving duplex phased array antenna, and belongs to the technical field of phased array antennas. The system comprises a scaling extension, a wave control extension, a receiving/transmitting scaling network combination, a receiving/transmitting feed network combination, a coupler and a receiving/transmitting channel. According to the invention, a single carrier signal generated in the scaling extension set forms a signal loop in the whole system through the coupler, the signal carrying channel amplitude and phase information is transmitted back to the scaling extension set, the signal amplitude and phase information is resolved in the scaling extension set, and then the channel amplitude and phase information is compensated to each active channel of the phased array through the wave control extension set, so that the amplitude and phase calibration of the phased array antenna is realized. The components of the system are the main components of the phased array antenna, and the rapid calibration of the phased array antenna can be realized without external equipment.)

1. An internal calibration system for a transceiving duplex phased-array antenna is characterized by comprising a calibration extension, a wave control extension, a receiving radio-frequency path and a transmitting radio-frequency path;

the scaling extension set comprises a scaling excitation channel, a scaling receiving channel and a communication and signal processing module; the calibration excitation channel generates an intermediate frequency signal, the intermediate frequency signal is connected with a receiving radio frequency channel and a transmitting radio frequency channel through a first gating switch, and the intermediate frequency signal is up-converted and then output to the receiving radio frequency channel or the transmitting radio frequency channel under the gating action of the first gating switch, so that a receiving single carrier signal is output for the receiving radio frequency channel or a transmitting single carrier signal is output for the transmitting radio frequency channel; the calibration receiving channel is connected with the receiving radio frequency channel and the transmitting radio frequency channel through a second gating switch, receives a loop signal of the receiving radio frequency channel or the transmitting radio frequency channel under the gating action of the second gating switch, down-converts the received loop signal into an intermediate frequency signal, and outputs a digital loop signal to the communication and signal processing module after A/D conversion; the communication and signal processing module is communicated with the wave control extension and is used for carrying out amplitude-phase calculation on the digital loop signals sent by the calibration receiving channel;

the wave control extension is used as a control center, interacts with the calibration extension on one hand, sends a calibration instruction and channel switch information, receives channel numbers and channel amplitude and phase information, and compensates amplitude and phase of each active channel of the phased array; on the other hand, according to the channel time-sharing calibration sequence, the corresponding channel is opened at a certain time, and the channel is set to be in an initial state;

the receiving radio frequency path comprises a receiving scaling network combination, a first channel selector switch, a plurality of parallel receiving channels and a receiving feed network combination which are connected in sequence, and the front end of each receiving channel is provided with a coupler; the transmitting radio frequency path comprises a transmitting feed network combination, a second path change-over switch, a plurality of parallel transmitting channels and a transmitting calibration network combination which are connected in sequence, and the rear end of each transmitting channel is provided with a coupler; the first/second channel switch is used for switching different receiving/transmitting channels to realize the selection of the channel to be calibrated, the coupler is used for forming a calibration signal, and each receiving/transmitting channel is used for realizing the amplification, filtering and amplitude-phase control of the signal.

2. An internal calibration method of a transmitting-receiving duplex phased array antenna is characterized by comprising the following steps:

1) in the process of antenna development, carrying out external field calibration on an antenna in a darkroom, and obtaining an initial amplitude matrix [ A1_ out ] and a phase matrix [ psi 1_ out ] of transceiving of each channel of the antenna, wherein the antenna is provided with an internal calibration system according to claim 1;

2) starting an internal calibration system to obtain an initial amplitude matrix [ A1_ in ] and a phase matrix [ psi 1_ in ] of each channel for transceiving, and subtracting the two matrixes to obtain internal calibration reference data: [A1] = a1_ in ] - [ a1_ out ] and ψ 1] = [ ψ 1_ in ] - [ ψ 1_ out ]; storing the amplitude and phase matrixes [ A1_ out ], [ psi 1_ out ] and [ A1], [ psi 1] in FLASH of the wave control extension set;

3) when the antenna is used for the first time in an installation machine, firstly performing in-line calibration, and respectively subtracting a directly measured real-time internal calibration amplitude matrix [ A2_ in ] and a directly measured phase matrix [ psi 2_ in ] from [ A1] and [ psi 1] to obtain [ A2], [ psi 2], and storing the obtained product in FLASH of a wave control extension;

4) in the long-term use process of the antenna, the amplitude matrix [ A2] and the phase matrix [ psi 2] are loaded into an RAM in the FPGA from the FLASH every time when the antenna is powered on; if online real-time internal calibration is needed, subtracting the directly measured real-time internal calibration amplitude matrix [ A3_ in ] and phase matrix [ psi 3_ in ] from [ A1] and [ psi 1] respectively to obtain [ A3] and [ psi 3], and writing the [ A2] and [ psi 2] in the RAM; if online real-time internal calibration is not needed, the data in the RAM is consistent with the internal calibration data when leaving the factory, and the data are both [ A2] and [ psi 2 ];

5) and correcting the initial phase data by taking the variation [ delta A ] = [ A3] - [ A2] of the real-time internal calibration amplitude matrix as a basis for judging whether the antenna is normal or not and taking the variation [ delta psi ] = [ psi 3] - [ psi 2] of the real-time internal calibration phase matrix as a phase correction difference value.

Technical Field

The invention relates to an internal calibration system and method for a transmitting-receiving duplex phased array antenna, belonging to the technical field of phased array antennas.

Background

The precondition of the phased array antenna for exerting excellent electrical performance is the precise control of the amplitude and phase distribution of the array surface, namely, the amplitude and phase distribution of the array unit is required to be consistent with the expected value meeting the pointing requirement. However, in an actual phased array antenna system, due to the amplitude and phase errors, the amplitude and phase consistency of the array elements is difficult to satisfy. The existence of the amplitude and phase error of the array elements can cause the gain of the phased array antenna to be reduced, and the beam pointing precision is reduced, so that the working performance of the phased array antenna is influenced. Therefore, for phased array antennas of any application area, a wavefront amplitude phase calibration is inevitable.

After the phased array antenna is assembled, the amplitude and the phase of an array element must be calibrated, so that the antenna performance reaches the best state. However, after the antenna is delivered to a user for a period of time, under the influence of the use environment, the radio frequency channel of the antenna may generate phase drift, which finally causes the radiation performance of the full array to be significantly affected and the scanning capability to be reduced. The phased array antenna has wide application prospects on platforms such as vehicle-mounted platforms, airborne platforms and satellite-mounted platforms, and partial platforms require the phased array antenna to be capable of monitoring and correcting the amplitude phase of the phased array antenna without disassembling the machine or using auxiliary equipment. Therefore, the phased array antenna has an online calibration function and is one of the core competitiveness of the phased array antenna.

The mutual coupling method does not need extra calibration equipment, can realize the online calibration of the antenna array, but needs the mutual coupling among the units to meet the symmetry condition or the mutual coupling coefficient (amplitude-phase information) is known, so strict requirements are put on the antenna unit directional diagram and the unit arrangement, or the transmission coefficient among the antenna units of the antenna array surface needs to be accurately measured, and the required workload is immeasurable for a large phased array antenna.

The other mutual coupling method is to adopt a coupler to carry out closed-loop coupling on signals at an antenna port to realize a signal loop, and the method has the advantages that the inconsistency of mutual coupling coefficients is not needed to be considered, and the defects that the coupled signals do not contain amplitude-phase information of the passive antenna array and other methods are needed to calibrate the amplitude-phase characteristics of the antenna array.

Disclosure of Invention

The invention aims to solve the problems and provides an internal calibration system and an internal calibration method for a transmitting-receiving duplex phased-array antenna.

In order to achieve the purpose, the invention adopts the technical scheme that:

an internal calibration system for a transceiving duplex phased-array antenna comprises a calibration extension, a wave control extension, a receiving radio-frequency path and a transmitting radio-frequency path;

the scaling extension set comprises a scaling excitation channel, a scaling receiving channel and a communication and signal processing module; the calibration excitation channel generates an intermediate frequency signal, the intermediate frequency signal is connected with a receiving radio frequency channel and a transmitting radio frequency channel through a first gating switch, and the intermediate frequency signal is up-converted and then output to the receiving radio frequency channel or the transmitting radio frequency channel under the gating action of the first gating switch, so that a receiving single carrier signal is output for the receiving radio frequency channel or a transmitting single carrier signal is output for the transmitting radio frequency channel; the calibration receiving channel is connected with the receiving radio frequency channel and the transmitting radio frequency channel through a second gating switch, receives a loop signal of the receiving radio frequency channel or the transmitting radio frequency channel under the gating action of the second gating switch, down-converts the received loop signal into an intermediate frequency signal, and outputs a digital loop signal to the communication and signal processing module after A/D conversion; the communication and signal processing module is communicated with the wave control extension and is used for carrying out amplitude-phase calculation on the digital loop signals sent by the calibration receiving channel;

the wave control extension is used as a control center, interacts with the calibration extension on one hand, sends a calibration instruction and channel switch information, receives channel numbers and channel amplitude and phase information, and compensates amplitude and phase of each active channel of the phased array; on the other hand, according to the channel time-sharing calibration sequence, the corresponding channel is opened at a certain time, and the channel is set to be in an initial state;

the receiving radio frequency path comprises a receiving scaling network combination, a first channel selector switch, a plurality of parallel receiving channels and a receiving feed network combination which are connected in sequence, and the front end of each receiving channel is provided with a coupler; the transmitting radio frequency path comprises a transmitting feed network combination, a second path change-over switch, a plurality of parallel transmitting channels and a transmitting calibration network combination which are connected in sequence, and the rear end of each transmitting channel is provided with a coupler; the first/second channel switch is used for switching different receiving/transmitting channels to realize the selection of the channel to be calibrated, the coupler is used for forming a calibration signal, and each receiving/transmitting channel is used for realizing the amplification, filtering and amplitude-phase control of the signal.

An internal calibration method of a transmitting-receiving duplex phased array antenna comprises the following steps:

1) in the process of antenna development, carrying out external field calibration on an antenna in a darkroom, and obtaining an initial amplitude matrix [ A1_ out ] and a phase matrix [ psi 1_ out ] of transceiving of each channel of the antenna, wherein the antenna is provided with an internal calibration system according to claim 1;

2) starting an internal calibration system to obtain an initial amplitude matrix [ A1_ in ] and a phase matrix [ psi 1_ in ] of each channel for transceiving, and subtracting the two matrixes to obtain internal calibration reference data: [A1] = a1_ in ] - [ a1_ out ] and ψ 1] = [ ψ 1_ in ] - [ ψ 1_ out ]; storing the amplitude and phase matrixes [ A1_ out ], [ psi 1_ out ] and [ A1], [ psi 1] in FLASH of the wave control extension set;

3) when the antenna is used for the first time in an installation machine, firstly performing in-line calibration, and respectively subtracting a directly measured real-time internal calibration amplitude matrix [ A2_ in ] and a directly measured phase matrix [ psi 2_ in ] from [ A1] and [ psi 1] to obtain [ A2], [ psi 2], and storing the obtained product in FLASH of a wave control extension;

4) in the long-term use process of the antenna, the amplitude matrix [ A2] and the phase matrix [ psi 2] are loaded into an RAM in the FPGA from the FLASH every time when the antenna is powered on; if online real-time internal calibration is needed, subtracting the directly measured real-time internal calibration amplitude matrix [ A3_ in ] and phase matrix [ psi 3_ in ] from [ A1] and [ psi 1] respectively to obtain [ A3] and [ psi 3], and writing the [ A2] and [ psi 2] in the RAM; if online real-time internal calibration is not needed, the data in the RAM is consistent with the internal calibration data when leaving the factory, and the data are both [ A2] and [ psi 2 ];

5) and correcting the initial phase data by taking the variation [ delta A ] = [ A3] - [ A2] of the real-time internal calibration amplitude matrix as a basis for judging whether the antenna is normal or not and taking the variation [ delta psi ] = [ psi 3] - [ psi 2] of the real-time internal calibration phase matrix as a phase correction difference value.

The invention has the beneficial effects that:

1. the invention realizes the calibration of the passive antenna array amplitude-phase data by an external field calibration method, and finally obtains the array surface amplitude-phase distribution data of the whole phased array antenna system by adding the obtained amplitude-phase data of the radio frequency access.

2. Compared with the antenna unit mutual coupling method, the method of the invention has the advantages of simple and convenient realization and small workload; compared with the existing coupler signal coupling mode, the calibration data is more accurate and credible due to the consideration of the amplitude-phase error of the passive antenna array.

Drawings

FIG. 1 is a functional block diagram of an internal calibration system in an embodiment of the present invention.

FIG. 2 is a flow chart of the operation of the internal calibration system in an embodiment of the present invention.

Fig. 3 is a transmission frequency point pattern of the internal calibration system in the embodiment of the present invention.

Fig. 4 is a receiving frequency point pattern of the internal calibration system in the embodiment of the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

As shown in fig. 1, an internal calibration system for a duplexer phased array antenna consists of a calibration extension, a wave control extension, a receiving radio frequency path and a transmitting radio frequency path.

In the phased array antenna test, firstly, the amplitude and phase data of the passive antenna array are calibrated by an external field calibration method, and the defects of an internal calibration method adopting a coupler are overcome.

The scaling extension set comprises a scaling excitation channel, a scaling receiving channel, a gating switch and a communication and signal processing module. The calibration excitation channel generates an intermediate frequency signal, and receives or transmits a single carrier signal through optional up-conversion output; the calibration receiving channel inputs signals of a receiving loop or a transmitting loop, the signals are converted into intermediate frequency signals through selectable down conversion, and digital signals are output through A/D; the gating switch realizes the selection of the transmitting frequency and the receiving frequency; and the communication and signal processing module is communicated with the wave control extension and simultaneously realizes amplitude-phase calculation of signals of the receiving loop or the transmitting loop.

The wave control extension is used as a control center, on one hand, the wave control extension interacts with the calibration extension, transmits calibration instructions and channel switch information, receives channel numbers and channel amplitude and phase information, and finally compensates amplitude and phase of each active channel of the phased array; and on the other hand, according to the channel time-sharing calibration sequence, opening the corresponding channel at a certain time, and setting the channel to be in an initial state.

The radio frequency path is divided into a receiving radio frequency path and a transmitting radio frequency path, the receiving/transmitting radio frequency path is composed of a receiving/transmitting scaling network combination, a channel switch, a coupler, a receiving/transmitting channel and a receiving/transmitting feed network combination, the channel switch realizes the selection of the channel to be calibrated, the coupler is a key device for forming a calibration signal loop, and the multi-channel receiving/transmitting channel realizes the functions of signal amplification, filtering, amplitude and phase control and the like.

The system mainly comprises two loops: a control loop and a signal loop.

The control loop consists of a wave control extension of the antenna, a communication and signal processing module of the scaling extension and an amplitude-phase control chip of the assembly;

the signal loop circuit is composed of a calibration exciting channel, a calibration receiving channel, an amplification channel of the component, a synthesis/power division channel of the network and the like of the calibration extension, and realizes the operations of signal generation, frequency conversion, analog-digital/digital-analog conversion, amplification, filtering, synthesis/power division and the like.

The antenna internal calibration system adopts the microstrip coupling line in the radio frequency channel and the calibration network as the reference of the internal calibration system, so the calibration reference is calibrated firstly. Firstly, a set of initial amplitude and phase values of the whole system are obtained by adopting an external field calibration method, a set of channel amplitude and phase data containing a calibration standard is obtained by adopting an internal calibration method, the two sets of data are subtracted to obtain the amplitude and phase data containing the passive antenna array, the micro-strip coupling line in the radio frequency channel and the calibration network, and the data is stored and used as the reference data of internal calibration.

The work flow of the internal calibration system is planned to four steps:

1) in the process of antenna development, the external field calibration of the antenna in a darkroom is carried out, and an initial amplitude matrix [ A1_ out ] and a phase matrix [ psi 1_ out ] of each channel transceiving of the antenna are obtained at the moment. The internal calibration system is started, and according to the workflow of fig. 2, an initial amplitude matrix [ a1_ in ] and a phase matrix [ psi 1_ in ] of each channel transceiving are obtained. Subtracting the two to obtain internal calibration reference data: [A1] = a1_ in ] - [ a1_ out ], [ ψ 1] = [ ψ 1_ in ] - [ ψ 1_ out ]. Storing the amplitude and phase matrixes [ A1_ out ], [ psi 1_ out ] and [ A1], [ psi 1] in FLASH of the wave control extension set;

2) when the antenna is used for the first time in an installation machine, firstly performing in-line calibration, and respectively subtracting a directly measured real-time in-calibration amplitude matrix [ A2_ in ] and a directly measured phase matrix [ psi 2_ in ] from [ A1] and [ psi 1] to obtain [ A2] and [ psi 2], and storing the two in FLASH of a wave control extension;

3) in the long-term use process of the antenna, the amplitude matrix [ A2] and the phase matrix [ psi 2] are loaded into the RAM in the FPGA from the FLASH every time when power is on. If on-line real-time internal calibration is needed, directly measured real-time internal calibration amplitude matrix [ A3_ in ] and phase matrix [ psi 3_ in ] are respectively subtracted from [ A1], [ psi 1] to obtain [ A3], [ psi 3], and the obtained values are written into the RAM to be covered with [ A2], [ psi 2 ]. If online real-time internal calibration is not needed, the data in the RAM is consistent with the internal calibration data when leaving the factory, and the data are both [ A2] and [ psi 2 ];

4) real-time internal calibration amplitude matrix variation: [ Δ a ] = [ A3] - [ a2], which is used as a basis for determining whether the antenna is normal. Real-time internal calibration phase matrix variation: [ Δ ψ ] = [ ψ 3] - [ ψ 2], and the initial phase data is corrected as a phase correction difference value.

Considering that the channel phase test is greatly influenced by temperature, a temperature monitoring circuit can be designed in the tested channel, and the internal calibration of the antenna is ensured to be carried out under the similar temperature condition through real-time temperature monitoring.

The communication and signal processing module is a core processing part of the scaling extension, and mainly completes the functions of AD sampling, signal amplitude and phase resolving, RS-422 communication and the like. And the two paths of intermediate frequency signals are subjected to AD sampling and then sent into the FPGA, and are stored in an RAM inside the FPGA in parallel, and are subjected to RAM read-write control and one-time parallel reading, so that various operations and processing are realized inside the FPGA, and the relative amplitude and phase are obtained. And sending the calculated result to the wave control mainboard for storage through the RS-422, and receiving an instruction sent by the wave control mainboard.

As can be seen from the directional diagram comparison of the inner calibration and the outer calibration of fig. 3 and 4, the two directional diagram curves are almost consistent, and only have a difference in the far side lobe direction. The test result shows that the internal calibration system recovers the initial performance of the antenna and achieves the expected effect.

The embodiment shows that the method is simple and convenient to implement, and the fast high-precision calibration of the phased array antenna can be realized on line in the use process of the antenna installation machine.

In a word, the single carrier signal generated in the scaling extension set forms a signal loop in the whole system through the coupler, the signal carrying the channel amplitude and phase information is transmitted back to the scaling extension set, the signal amplitude and phase information is resolved in the scaling extension set, and then the channel amplitude and phase information is compensated to each active channel of the phased array through the wave control extension set, so that the amplitude and phase calibration of the phased array antenna is realized. The components of the internal calibration system are all main components of the phased array antenna, and the rapid calibration of the phased array antenna can be realized without external equipment.