CN112698282B - Internal calibration device and internal calibration method for DBF (digital binary field) satellite-borne SAR (synthetic aperture radar) system - Google Patents
Internal calibration device and internal calibration method for DBF (digital binary field) satellite-borne SAR (synthetic aperture radar) system Download PDFInfo
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Abstract
The embodiment of the application discloses an internal calibration device of a DBF satellite-borne SAR system, which comprises the following components: the device comprises an internal calibration module and a data fusion module; the internal calibration module receives the calibration signal, converts the frequency of the calibration signal and outputs the frequency-converted calibration signal; the data fusion module receives the frequency-converted scaling signal, converts the frequency-converted scaling signal into a digital scaling signal and scales according to the digital scaling signal. In addition, the embodiment of the application also discloses an internal calibration method suitable for the DBF spaceborne SAR system.
Description
Technical Field
The embodiments of the present application relate to the field of communication technologies, and relate to, but are not limited to, an in-system calibration device and an in-system calibration method for a digital beam forming (Digital Beam Forming, DBF) satellite-borne synthetic aperture radar (Synthetic Aperture Radar, SAR).
Background
The satellite-borne SAR system transceiving path characteristics are influenced by factors such as temperature change, certain uncertainty exists, and the uncertainty can influence SAR image radiometric calibration precision and image distance pulse compression effect.
The internal calibration is introduced into the satellite-borne SAR system for solving the problems, and the implementation mode is that special equipment for calibration is configured in the system, a connection is established between the system transceiving channels, the connection is used for calibrating the characteristics of the whole active transceiving channels except the antenna array surface, and corresponding compensation is carried out according to the calibration result during ground imaging processing.
For a phased array spaceborne SAR system, the conventional internal calibration design scheme comprises the following steps: an internal scaler and an antenna scaling network are added outside the normal radar transceiver channel. However, after the DBF technology is adopted, the composition of the receiving and transmitting channel of the spaceborne SAR system is greatly changed from that of the conventional system, and the internal calibration design scheme is not applicable.
In the related art, the internal calibration design scheme of the alternative DBF spaceborne SAR system comprises: the design is much more complex than the conventional internal calibration design by adding a plurality of electronic switches and a plurality of high-frequency cables between each DBF receiving module and the receiving and transmitting channels.
Disclosure of Invention
In view of this, the embodiment of the application provides an in-DBF spaceborne SAR system scaling device and an in-scaling method for solving at least one problem existing in the related art, and the receiving and collecting of the scaling signal are realized by introducing a separate scaling receiving channel, so that a plurality of electronic switches and a plurality of high-frequency cables are avoided, and an in-scaling scheme is simplified.
The technical scheme of the embodiment of the application is realized as follows:
in a first aspect, embodiments of the present application provide an in-DBF space-borne SAR system scaling apparatus, including: the device comprises an internal calibration module and a data fusion module;
the internal calibration module receives the calibration signal, converts the frequency of the calibration signal and outputs the frequency-converted calibration signal;
the data fusion module receives the frequency-converted scaling signal, converts the frequency-converted scaling signal into a digital scaling signal and scales according to the digital scaling signal.
In a second aspect, embodiments of the present application provide an internal calibration method, the method including:
receiving a calibration signal through a internal calibration module, and carrying out frequency conversion on the calibration signal;
and converting the frequency-converted scaling signal into a digital scaling signal through a data fusion module, and scaling according to the digital scaling signal.
In this embodiment of the present application, the internal calibration device of the DBF on-board SAR system includes: the device comprises an internal calibration module and a data fusion module; the internal calibration module receives the calibration signal, converts the frequency of the calibration signal and outputs the frequency-converted calibration signal; the data fusion module receives the frequency-converted calibration signal, converts the frequency-converted calibration signal into a digital calibration signal and calibrates according to the digital calibration signal; therefore, through frequency conversion receiving of the calibration signals and conversion of the frequency converted calibration signals into digital calibration signals, receiving and collecting of the calibration signals are achieved, and the internal calibration scheme is simplified.
Drawings
Fig. 1 is a schematic diagram of the composition structure of a scaling device in a DBF spaceborne SAR system according to an embodiment of the present application;
fig. 2 is a schematic diagram of a second component structure of the scaling device in the DBF spaceborne SAR system according to an embodiment of the present application;
fig. 3 is a schematic diagram III of the composition structure of a scaling device in a DBF spaceborne SAR system according to an embodiment of the present application;
fig. 4 is a schematic diagram of a composition structure of a scaling device in a DBF spaceborne SAR system according to an embodiment of the present application;
fig. 5 is a schematic diagram five of a composition structure of a scaling device in a DBF spaceborne SAR system according to an embodiment of the present application;
fig. 6 is a schematic diagram sixth of the composition structure of the scaling device in the DBF spaceborne SAR system provided in the embodiment of the present application;
fig. 7 is a schematic flowchart of an implementation flow of an internal calibration method according to an embodiment of the present application;
fig. 8 is a schematic diagram seventh of a composition structure of a scaling device in a DBF spaceborne SAR system according to an embodiment of the present application;
fig. 9 is a schematic diagram eight of a composition structure of a scaling device in a DBF spaceborne SAR system according to an embodiment of the present application;
fig. 10 is a schematic diagram nine of a composition structure of a scaling device in a DBF spaceborne SAR system according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application more clear, the specific technical solutions of the present application will be described in further detail below with reference to the accompanying drawings in the embodiments of the present application. The following examples are illustrative of the present application, but are not intended to limit the scope of the present application.
In describing embodiments of the present application in detail, the cross-sectional view of the device structure is not partially exaggerated to a general scale for convenience of description, and the schematic drawings are merely examples, which should not limit the scope of protection of the present application herein. In addition, the three-dimensional dimensions of length, width and depth should be included in actual fabrication.
The embodiment of the application provides an intra-DBF spaceborne SAR system scaling device, as shown in fig. 1, the intra-DBF spaceborne SAR system scaling device 100 includes: an internal scaling module 101 and a data fusion module 102.
The internal scaling module 101 is configured to receive the scaling signal, convert the frequency of the scaling signal, and output the scaled signal after the frequency conversion.
The data fusion module 102 is configured to receive the frequency-converted scaling signal output by the internal scaling module 101, convert the frequency-converted scaling signal into a digital scaling signal, and perform scaling according to the digital scaling signal.
Here, the internal calibration module 101 is connected to the data fusion module 102, and the internal calibration module 101 transmits the frequency-converted calibration signal to the data fusion module 102 through the connection. The internal calibration module 101 may include a calibration receiving unit and the data fusion module 102 may include a calibration acquisition unit, which may be wired to the calibration acquisition unit.
And receiving a scaling signal through the scaling receiving unit, carrying out frequency conversion on the scaling signal, and outputting the frequency-converted scaling signal.
The scaled signals output by the scaled receiving unit are received through the scaled collecting unit, the scaled signals after frequency conversion are converted into digital scaled signals, and scaling is carried out according to the digital scaled signals.
In an embodiment of the present application, the apparatus includes: the device comprises an internal calibration module and a data fusion module; the internal calibration module receives the calibration signal, converts the frequency of the calibration signal and outputs the frequency-converted calibration signal; the data fusion module receives the frequency-converted calibration signal, converts the frequency-converted calibration signal into a digital calibration signal and calibrates according to the digital calibration signal; therefore, the receiving and the collecting of the calibration signals are realized through the frequency conversion receiving of the calibration signals and the conversion of the frequency converted calibration signals into digital calibration signals, and the internal calibration scheme is simplified.
In one embodiment, as shown in fig. 2, the apparatus 100 further comprises: a frequency modulated signal generation module 103; the frequency modulation signal generating module 103 is configured to generate a chirp signal.
Here, the frequency modulation signal generation module 103 is connected to the internal calibration module 101, the frequency modulation signal generation module 103 generates a chirp signal, and the frequency modulation signal generation module 103 transmits the generated chirp signal to the internal calibration module 101 directly or indirectly as a calibration signal.
In one example, the frequency modulated signal generation module 103 directly sends the chirp signal as a scaled signal to the internal scaling module. In one example, the fm signal generation module 103 sends the chirp signal to an antenna array module, which processes the chirp signal to obtain a scaled signal and transmits the scaled signal to an internal scaling module.
In the embodiment of the application, the frequency modulation signal generating module generates the linear frequency modulation signal, transmits the linear frequency modulation signal to the internal calibration module, performs frequency conversion processing of the internal calibration module, and transmits the processed linear frequency modulation signal to the data fusion module, so that an internal calibration scheme is realized, and the linear frequency modulation signal is provided for the internal calibration scheme.
In one embodiment, as shown in fig. 2, in the reference calibration mode, the fm signal generating module 103 transmits the chirp signal as a first calibration signal to the internal calibration module 101, where the calibration signal includes: reference is made to a first scaling signal of the scaling mode. In the embodiment of the present application, the scaling signal of the reference scaling mode is referred to as a first scaling signal.
Here, in the reference scaling mode, the reference scaling path of the apparatus includes: the frequency modulation signal generation module 103, the internal calibration module 101 and the data fusion module 102. The frequency modulation signal generation module 103 is connected with the internal calibration module 101, and the internal calibration module 101 is connected with the data fusion module 102.
Here, the frequency modulation signal generating module 103 generates a chirp signal, the frequency modulation signal generating module 103 transmits the generated chirp signal as a first calibration signal to the internal calibration module 101, and the internal calibration module 101 receives the first calibration signal transmitted by the frequency modulation signal generating module 103, performs frequency conversion on the first calibration signal, and outputs the frequency-converted first calibration signal. The reference to a chirp signal in the scaling mode is referred to herein as a first scaling signal.
Here, the data fusion module 102 receives the variable-frequency first scaling signal transmitted by the internal scaling module 101, and converts the variable-frequency first scaling signal into a digital scaling signal, and performs scaling according to the digital scaling signal.
In an embodiment of the present application, a reference scaling path of a scaling device in a DBF spaceborne SAR system in a reference scaling mode includes: the frequency modulation signal generation module, the internal calibration module and the data fusion module; the frequency modulation signal generation module generates a linear frequency modulation signal, the linear frequency modulation signal is used as a first calibration signal to be transmitted to the internal calibration module, the first calibration signal after frequency conversion is obtained through the processing of the internal calibration module, and the first calibration signal is transmitted to the data fusion module to obtain a digital calibration signal, so that the calibration of a reference calibration channel in the internal calibration scheme is realized.
In one embodiment, as shown in fig. 3, the apparatus 100 further comprises: an antenna array module 104; in the transmit scaling mode, the fm signal generation module 103 transmits the chirp signal as a transmit signal to the antenna array module 104; the antenna array module 104 receives the transmitting signal, and couples and outputs the transmitting signal to obtain a second calibration signal, and transmits the second calibration signal to the internal calibration module 101. At this time, the scaling signal includes: a second scaling signal of the scaling mode is transmitted.
Here, the fm signal generating module 103 is connected to the antenna array module 104, the antenna array module 104 is connected to the internal calibration module 101, the internal calibration module 101 is connected to the data fusion module 102, and the signal transmission path is: the frequency modulation signal generation module 103, the antenna array module 104, the internal calibration module 101 and the data fusion module 102.
Here, the transmit scaling path in the transmit scaling mode includes: the frequency modulation signal generation module 103, the antenna array module 104, the internal calibration module 101 and the data fusion module 102.
The frequency modulation signal generation module 103 generates a linear frequency modulation signal, the frequency modulation signal generation module 103 transmits the generated linear frequency modulation signal as a transmitting signal to the antenna array module 104, the antenna array module 104 receives the transmitting signal transmitted by the frequency modulation signal generation module 103, performs coupling output and power synthesis on the transmitting signal to obtain a second calibration signal, the second calibration signal is transmitted to the inner calibration module 101, the inner calibration module 101 receives the second calibration signal, performs frequency conversion on the second calibration signal, and outputs the second calibration signal after frequency conversion to the data fusion module 102; the data fusion module 102 receives the converted second scaling signal, and converts the converted second scaling signal into a digital scaling signal, and scales according to the digital scaling signal.
In an embodiment of the present application, a transmit scaling path in a transmit scaling mode includes: the system comprises a frequency modulation signal generation module, an antenna array module, an internal calibration module and a data fusion module; the frequency modulation signal generating module generates a linear frequency modulation signal, the linear frequency modulation signal is used as a transmitting signal to the antenna array module and the internal calibration module, the antenna array module and the internal calibration module are used for processing to obtain a second calibration signal after frequency conversion, and the second calibration signal is transmitted to the data fusion module to obtain a digital calibration signal, so that the calibration of a transmitting calibration channel in an internal calibration scheme is realized.
In one embodiment, as shown in fig. 4, the antenna array module 104 includes: an antenna transceiver unit 1041 and an antenna scaling network unit 1042. The antenna transceiver unit 1041 includes a plurality of transceiver components.
In practical application, the antenna transceiver unit includes a plurality of transceiver components, and each transceiver component includes at least one transceiver path. In the transmit calibration mode, the transmit path in the transmit-receive path is in operation.
The antenna transceiver unit 1041 is configured to receive a transmission signal, and couple the transmission signal to the antenna network scaling unit through each transceiver component after power distribution.
The antenna scaling network unit 1042 is configured to perform power synthesis on the transmission signals coupled and output by the different transceiver components to obtain the second scaling signal, and send the second scaling signal to the internal scaling module number.
Here, the antenna transceiving unit 1041 is connected to the antenna scaling network unit 1042. The antenna transceiver unit performs power distribution and power amplification on the transmission signal, and couples the transmission signal transmitted by the channel corresponding to each transceiver component to the antenna scaling network unit 1042. The antenna scaling network unit 1042 performs power synthesis on the received transmit signals coupled out by the transceiver components to obtain a signal, i.e. a second scaling signal.
Here, the transmit scaling path in the transmit scaling mode includes: the frequency modulation signal generation module 103, the antenna transceiver unit 1041, the antenna scaling network unit 1042, the internal scaling module 101 and the data fusion module 102.
Here, the fm signal generating module 103 generates a chirp signal, the fm signal generating module 103 transmits the generated chirp signal as a transmission signal to the antenna transceiver unit 1041, the antenna transceiver unit 1041 receives the transmission signal transmitted by the fm signal generating module 103, performs power distribution and power amplification on the transmission signal, and couples the transmission signals of each path to the antenna scaling network unit 1042; the antenna calibration network unit 1042 performs power synthesis on the received transmitting signal to obtain a second calibration signal, transmits the second calibration signal to the internal calibration module 101, receives the second calibration signal by the internal calibration module 101, performs frequency conversion on the second calibration signal, and outputs the second calibration signal after frequency conversion to the data fusion module 102; the data fusion module 102 receives the converted second scaling signal, and converts the converted second scaling signal into a digital scaling signal, and scales according to the digital scaling signal.
In an embodiment of the present application, in a transmit scaling mode, a transmit scaling path of an apparatus comprises: the system comprises a frequency modulation signal generation module, an antenna receiving and transmitting unit, an antenna calibration network unit and a data fusion module, wherein the frequency modulation signal generation module, the antenna receiving and transmitting unit, the antenna calibration network unit and the internal calibration module are connected with the data fusion module; the frequency modulation signal generating module generates a linear frequency modulation signal, the linear frequency modulation signal is used as a transmitting signal to be transmitted to the antenna receiving and transmitting unit, the antenna calibration network unit and the internal calibration module, the antenna receiving and transmitting unit, the antenna calibration network unit and the internal calibration module are used for processing to obtain a second calibration signal after frequency conversion, and the second calibration signal is transmitted to the data fusion module to obtain a digital calibration signal, so that calibration of a transmitting calibration channel in an internal calibration scheme is realized.
In one embodiment, as shown in fig. 5, the apparatus comprises: a DBF reception processing module 105; the DBF receive processing module 105 is configured to perform scaling in a receive scaling mode.
Here, the internal calibration module receives the chirp signal in a reception calibration mode and transmits the chirp signal as a third calibration signal to the antenna array module;
the antenna array module amplifies the third calibration signal and transmits the third calibration signal to the DBF receiving and processing module;
the DBF receiving processing module is used for carrying out frequency conversion and amplification on the amplified third scaling signal, converting the third scaling signal into a digital scaling signal and scaling according to the digital scaling signal.
In practical application, the antenna array module includes a plurality of signal receiving and transmitting paths, and in a transmitting calibration mode, the signal receiving and transmitting paths are used as transmitting paths, and in a receiving calibration mode, the signal receiving and transmitting paths are used as receiving paths.
In one embodiment, as shown in fig. 5, in the receive scaling mode, the fm signal generation module 103 transmits the chirp signal as a third scaling signal to the internal scaling module 101; the internal scaling module 101 receives the third scaling signal and transmits it to the antenna array module 104; the antenna array module 104 amplifies the third calibration signal and transmits the amplified third calibration signal to the DBF receiving and processing module 105; the DBF reception processing module 105 frequency-converts and amplifies the received third scaling signal, and converts it into a digital scaling signal, and scales according to the digital scaling signal.
Here, in the receive scaling mode, the receive scaling path of the apparatus comprises: a frequency modulation signal generating module 103, an internal calibration module 101, an antenna array module 104 to a DBF receiving processing module 105; the frequency modulation signal generating module 103 is connected with the internal calibration module 101, the internal calibration module 101 is connected with the antenna array module 104, and the antenna array module 104 is connected with the DBF receiving and processing module 105.
In one example, as shown in fig. 6, the antenna array module 104 includes: an antenna transceiver unit 1041 and an antenna scaling network unit 1042; the antenna scaling network unit 1042 is connected to the antenna transceiver unit 1041, and the antenna scaling network unit 1042 transmits the chirp signal to the antenna transceiver unit 1041.
The antenna calibration network unit distributes power of the third calibration signal and transmits the third calibration signal to the antenna receiving and transmitting unit; and the antenna receiving and transmitting unit amplifies and synthesizes the third calibration signal after power distribution and then transmits the third calibration signal to the DBF receiving and processing module.
Here, the frequency-modulated signal generating module 103 transmits the chirp signal as a third calibration signal to the internal calibration module 101; the internal scaling module 101 receives the third scaling signal and transmits the third scaling signal to the antenna scaling network unit 1042; the antenna calibration network unit 1042 receives the third calibration signal, performs power distribution on the third calibration signal, and transmits the third calibration signal to the antenna transceiver unit 1041; the antenna transceiver unit 1041 receives the third calibration signal after power allocation, and transmits the third calibration signal to the DBF receiving and processing module 105 after amplification; the DBF reception processing module 105 frequency-converts and amplifies the third scaling signal, and converts it into a digital scaling signal, according to which scaling is performed.
In an embodiment of the present application, a receive scaling path in a receive scaling mode includes: the device comprises a frequency modulation signal generation module, an internal calibration module, an antenna array module and a DBF receiving and processing module; the frequency modulation signal generating module generates a linear frequency modulation signal, and transmits the linear frequency modulation signal as a third calibration signal to the internal calibration module, the antenna array module and the DBF receiving and processing module, and the digital calibration signal is obtained through the processing of the internal calibration module, the antenna array module and the DBF receiving and processing module, so that the calibration of the receiving calibration channel in the internal calibration scheme is realized.
Next, embodiments of the internal calibration method, device and storage medium provided in the embodiments of the present application are described with reference to a schematic diagram of an internal calibration device of a DBF spaceborne SAR system shown in fig. 1.
The embodiment of the application provides an internal calibration method which is applied to a DBF (direct current) satellite-borne SAR system internal calibration device, wherein the DBF satellite-borne SAR system internal calibration device can be computer equipment. The functions performed by the method may be performed by a processor in a computer device, which may of course be stored in a computer storage medium, as will be seen, comprising at least a processor and a storage medium.
Based on the internal calibration device of the DBF on-board SAR system shown in fig. 1, the embodiment of the present application provides an internal calibration method, as shown in fig. 7, which may include the following steps:
s701, receiving a calibration signal through a calibration module, and carrying out frequency conversion on the calibration signal;
here, the internal calibration device of the DBF on-board SAR system includes: an internal calibration module and a data fusion module; the internal calibration module is connected with the data fusion module; and receiving the scaling signal through the internal scaling module, carrying out frequency conversion on the received scaling signal, and outputting the frequency-converted scaling signal.
The internal calibration module receives the calibration signal in a transmitting calibration mode or a reference calibration mode, converts the received calibration signal into frequency, transmits the frequency-converted calibration signal to the data fusion module, and converts the frequency-converted calibration signal into a data calibration signal.
In an embodiment, a chirp signal is generated by a frequency modulation signal generation module, said chirp signal being used to obtain said scaled signal.
The internal calibration module can directly receive the linear frequency modulation signal from the frequency modulation signal generation module as a calibration signal, and can also receive the linear frequency modulation signal generated by the frequency modulation signal generation module through other modules, wherein the received signal is the linear frequency modulation signal processed by the other modules.
In this embodiment, as shown in fig. 2, the apparatus 100 further includes: a frequency modulated signal generation module 103; the frequency modulation signal generating module 103 is configured to generate a chirp signal.
In one example, the frequency modulated signal generation module 103 directly sends the chirp signal as a scaled signal to the internal scaling module.
In one example, the fm signal generation module 103 sends the chirp signal to an antenna array module, which processes the chirp signal to obtain a scaled signal and transmits the scaled signal to an internal scaling module.
Here, the scaling signal includes: the first scaling signal in the scaling mode is referenced and the second scaling signal in the scaling mode is transmitted. The method comprises the steps of transmitting a first calibration signal in a reference calibration mode or a second calibration signal in a transmission calibration mode to a data fusion module, and transmitting a third calibration signal in a receiving calibration mode to a DBF receiving and processing module.
S702, converting the frequency-converted scaling signal into a digital scaling signal through a data fusion module, and scaling according to the digital scaling signal.
Here, after the frequency-converted calibration signal is transmitted to the data fusion module, the frequency-converted calibration signal transmitted by the internal calibration module is received by the data fusion module, and the frequency-converted calibration signal is converted into a digital calibration signal, and calibration is performed according to the digital calibration signal.
In an embodiment of the present application, the internal calibration method includes: receiving a calibration signal through a internal calibration module, carrying out frequency conversion on the calibration signal, and outputting the calibration signal after frequency conversion; the data fusion module is used for receiving the frequency-converted calibration signal, converting the frequency-converted calibration signal into a digital calibration signal, and calibrating according to the digital calibration signal, so that the receiving and the acquisition of the transmitting calibration signal are realized by receiving the frequency conversion of the transmitting calibration signal and converting the frequency-converted transmitting calibration signal into the digital calibration signal. Therefore, the receiving and the acquisition of the transmitting calibration signal and the reference calibration signal are realized by introducing the independent calibration receiving channel, a plurality of electronic switches and a plurality of high-frequency cables are avoided, and the DBF spaceborne SAR internal calibration scheme is simplified.
In an embodiment, in a reference calibration mode, the chirp signal is transmitted by the fm signal generation module as a first calibration signal to the internal calibration module.
Here, in the reference calibration mode, the fm signal generation module, the default calibration module, and the data fusion module form a reference calibration path.
Generating a linear frequency modulation signal through a frequency modulation signal generating module, and transmitting the linear frequency modulation signal as a first calibration signal to an internal calibration module; and receiving the first calibration signal through the internal calibration module, carrying out frequency conversion on the first calibration signal, and outputting the frequency-converted first calibration signal to the data fusion module. And receiving the frequency-converted first calibration signal through a data fusion module, converting the frequency-converted first calibration signal into a digital calibration signal, and calibrating according to the digital calibration signal.
In the embodiment of the application, the linear frequency modulation signal is generated through the frequency modulation signal generation module, the linear frequency modulation signal is processed through the internal calibration module and the data fusion module, the digital calibration signal is obtained, and the calibration is carried out according to the digital calibration signal, so that the calibration of the reference calibration channel is realized.
In an embodiment, in a transmit scaling mode, the chirp signal is transmitted as a transmit signal to an antenna array module through the fm signal generating module, and a second scaling signal is obtained by coupling output of the transmit signal by the antenna array module, and the second scaling signal is transmitted to the internal scaling module.
In the transmitting calibration mode, the frequency modulation signal generating module, the antenna array module, the internal calibration module and the data fusion module form a transmitting calibration passage.
Here, a chirp signal is generated by the frequency modulation signal generation module, and transmitted as a transmission signal to the antenna array module;
and receiving the transmitting signal through the antenna array module, coupling and outputting the transmitting signal to form a second calibration signal, and transmitting the second calibration signal to the internal calibration module.
And receiving a second calibration signal through the internal calibration module, carrying out frequency conversion on the second calibration signal, and outputting the second calibration signal after frequency conversion to the data fusion module.
And receiving the second scaled signal after frequency conversion through a data fusion module, converting the second scaled signal after frequency conversion into a digital scaled signal, and scaling according to the digital scaled signal.
In the embodiment of the application, the linear frequency modulation signal is generated through the frequency modulation signal generation module, and is processed through the antenna array module, the internal calibration module and the data fusion module to obtain the digital calibration signal, and the calibration is carried out according to the digital calibration signal, so that the calibration of the transmitting calibration channel is realized.
In an example, in the receive scaling mode, the apparatus further comprises: the DBF receives the processing module. The frequency modulation signal generating module, the internal calibration module, the antenna array module and the DBF receiving processing module form a receiving calibration path. Wherein, antenna array module includes: an antenna transceiver unit and an antenna scaling network unit; in the receiving calibration mode, the antenna receiving and transmitting unit is used for receiving the linear frequency modulation signal; the antenna scaling network unit transmits the chirp signal to the antenna transceiver unit.
Here, a chirp signal is generated by the frequency modulation signal generation module, and is transmitted to the internal calibration module as a third calibration signal;
and receiving a third calibration signal through the internal calibration module and transmitting the third calibration signal to the antenna array module.
The third calibration signal is amplified through an antenna array module and then transmitted to a DBF receiving and processing module;
and the amplified third scaling signal is subjected to frequency conversion and amplification through a DBF receiving and processing module and converted into a digital scaling signal, and scaling is carried out according to the digital scaling signal.
In the embodiment of the application, the frequency modulation signal generating module generates the frequency modulation signal, the internal calibration module, the antenna array module and the DBF receiving and processing module process the frequency modulation signal to obtain the digital calibration signal, and the digital calibration signal is used for calibrating, so that the calibration of the receiving calibration channel is realized.
In the following, a default calibration scheme of the DBF spaceborne SAR system is taken as an example to further describe the default calibration device and the default calibration method of the DBF spaceborne SAR system provided in the embodiment of the present application.
In the related art, as the characteristics of a receiving and transmitting path of the spaceborne SAR system are influenced by factors such as temperature change, certain uncertainty exists, and the uncertainty can influence SAR image radiometric calibration precision and image distance pulse compression effect.
The internal calibration is introduced into the satellite-borne SAR system for solving the problems, and the implementation mode is that special equipment for calibration is configured in the system, a connection is established between the transceiving channels of the system, the connection is used for calibrating the characteristics of the whole active transceiving channel except the antenna array surface, and corresponding compensation is carried out according to the calibration result during ground imaging processing.
For conventional phased array on-board SAR systems, the internal calibration design scheme is mature, as shown in FIG. 8. The conventional phased array on-board SAR system comprises: a central device 81 and an active phased array antenna 82. Wherein the central device 81 comprises: a source 811 of frequency modulated signals, a data former 812, a radar receiver 813; the active phased array antenna 82 includes: an antenna feed network 821, a transceiving channel 822. An internal scaler 814 is added to the central unit 81, and an antenna scaling network 823 is added to the active phased array antenna 82, forming three internal scaling loops: a transmit scaling loop, a receive scaling loop, and a reference scaling loop.
Wherein the reference calibration loop is: frequency modulation signal source, internal scaler, radar receiver, data former.
The receiving calibration loop is as follows: frequency modulation signal source, internal scaler, antenna scaling network, antenna receiving channel, radar receiver and data former.
The emission calibration loop is as follows: frequency modulation signal source, antenna transmitting channel, antenna calibration network, internal scaler, radar receiver and data former.
In recent years, the DBF technology is started to be applied to a satellite-borne SAR system using a conventional phased array, and the DBF technology is used for receiving beams from SAR distance, so that the antenna receiving gain can be greatly improved, and the sensitivity and the distance ambiguity performance of the radar system are obviously improved.
However, after the DBF technology is adopted, the composition of the transceiving channel of the DBF spaceborne SAR system is greatly changed from that of the conventional phased array spaceborne SAR system, as shown in fig. 9. The DBF spaceborne SAR system comprises: a central electronics 91, an active phased array antenna 92 and a DBF receive processing unit 93. Wherein the central electronic device 91 comprises: a fm signal source 911 and a data fusion 912; the active phased array antenna 92 includes an antenna feed network 921 and a transmit receive path 922; the DBF reception processing unit 93 includes: the DBF unit 931, the receiving module 1, the receiving modules 2, …, and the receiving module N, wherein the receiving modules 1 to N constitute a receiving module 932. The receiving modules 1 to N are used for receiving the linear frequency modulation signals transmitted by different receiving and transmitting channels.
The conventional phased array spaceborne SAR system is used for centralized signal receiving and signal acquisition; wherein, the signal receiving is realized in the radar receiver, and the signal acquisition is realized in the data former; while DBF on-board SAR systems become multiple DBF receive and acquisition channels and are dispersed in different locations of the antenna.
Because of the difference between the composition of the receiving and transmitting channels of the DBF satellite-borne SAR system and the conventional phased array satellite-borne SAR system after the DBF technology is adopted, the conventional internal calibration design scheme is not directly applicable any more, and the internal calibration design scheme suitable for the DBF satellite-borne SAR system is necessary to be provided.
In a DBF on-board SAR system, a scaling loop similar to a conventional phased array on-board SAR system can be implemented by adding many electronic switches and high frequency cables between each DBF receiving module and the transmit-receive channel, but this makes the internal scaling design much more complex.
The embodiment of the application provides a novel internal calibration design scheme of a DBF satellite-borne SAR system, so as to adapt to the change of the system transceiving channel composition after the DBF technology of a distance-oriented receiving beam.
In order to achieve the above objective, the embodiments of the present application propose a new internal calibration design scheme for a DBF spaceborne SAR system, and by adding a separate calibration signal receiving and collecting channel, the required emission calibration and reference calibration are achieved, so that a plurality of electronic switches and a plurality of high-frequency cables are avoided from being introduced, and various requirements of the internal calibration of the system can be satisfied, as shown in fig. 10.
As can be seen from fig. 10, with respect to the internal calibration design scheme shown in fig. 9, the scheme proposed in the embodiment of the present application mainly makes two-point adjustment: 1) A scaling receiving module 1002 is added in the inner scaler 913 to realize the frequency conversion receiving of the scaling signal; 2) A scaling acquisition module 1001 is added in the data fusion device 912 to realize digital conversion of the scaling signal.
Here, the scaling receiving module 1002 is configured to perform frequency conversion receiving on the scaling signal; the calibration acquisition module 1004 is configured to convert the frequency-converted calibration signal into a digital calibration signal.
The internal calibration scheme provided by the embodiment of the application comprises the following calibration paths:
1) Reference scaling loop: frequency modulation signal source-internal scaler (scaling receiving) -data fusion (scaling acquisition);
2) Emission scaling loop: frequency modulation signal source, antenna transmitting channel, antenna calibration network, internal scaler (calibration receiving), data fusion (calibration acquisition);
3) Receiving a scaling loop: frequency modulation signal source, internal scaler, antenna scaling network, antenna receiving channel and DBF receiving channel.
The main characteristics of the internal calibration scheme provided by the embodiment of the application are as follows:
1) Compared with the internal calibration design scheme of a conventional phased array spaceborne SAR system, the signal receiving module and the signal acquisition module are only added in an original single machine, and the quantity of independently added equipment is small;
2) By introducing an independent calibration signal receiving and collecting channel, leakage of the receiving channel is avoided when transmitting calibration is carried out, and an optical fiber delay or a high isolation switch in the internal calibration scheme of a conventional phased array satellite-borne SAR system is not required to be considered, so that the internal calibration design scheme is simplified to a certain extent;
3) By including additional calibration signal receiving channels and acquisition channels in the reference calibration loop, the effect on the gain calibration of the transmit-receive channels can be eliminated.
The internal calibration scheme provided by the embodiment of the application can achieve the following beneficial effects:
a. aiming at the design requirement of a DBF satellite-borne SAR system adopting a DBF technology on the internal calibration, a new internal calibration design scheme is provided, and the problem that the conventional internal calibration scheme is not applicable any more due to the composition difference of a receiving and transmitting channel is solved;
b. the provided internal calibration design scheme for the DBF satellite-borne SAR system adopting the DBF technology only increases a signal receiving module and a signal acquisition module, and realizes the required system internal calibration function under the condition of increasing a small amount of equipment;
c. the provided internal calibration design scheme for the DBF satellite-borne SAR system adopting the DBF technology avoids leakage of a receiving channel during transmitting calibration by introducing an independent calibration signal receiving channel and a calibration signal acquisition channel, and simplifies the internal calibration design scheme without considering an optical fiber delay or a high isolation switch in a conventional internal calibration scheme.
It should be noted that, in the embodiment of the present application, if the above-mentioned internal calibration method is implemented in the form of a software functional module, and is sold or used as a separate product, it may also be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present application may be essentially or partially contributing to the related art, and the computer software product may be stored in a storage medium, and include several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read Only Memory (ROM), a magnetic disk, an optical disk, or other various media capable of storing program codes. Thus, embodiments of the present application are not limited to any specific combination of hardware and software.
Correspondingly, the embodiment of the present application provides a storage medium, i.e. a computer readable storage medium, on which a computer program is stored, which computer program, when being executed by a processor, implements the steps of the internal calibration method provided in the above embodiment.
It should be noted here that: the description of the storage medium above is similar to that of the method embodiments described above, with similar advantageous effects as the method embodiments. For technical details not disclosed in the storage medium of the present application, please refer to the description of the method embodiments of the present application for understanding.
It should be appreciated that reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present application. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be understood that, in various embodiments of the present application, the sequence numbers of the foregoing processes do not mean the order of execution, and the order of execution of the processes should be determined by the functions and internal logic thereof, and should not constitute any limitation on the implementation process of the embodiments of the present application. The foregoing embodiment numbers of the present application are merely for describing, and do not represent advantages or disadvantages of the embodiments.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
In the several embodiments provided in this application, it should be understood that the disclosed apparatus and method may be implemented in other ways. The above described embodiment of the apparatus is only illustrative, for example, the splitting of the units is only a logical functional splitting, and there may be other splitting manners in actual implementation, such as: multiple units or components may be combined or may be integrated into another system, or some features may be omitted, or not performed. In addition, the various components shown or discussed may be coupled or directly coupled or communicatively coupled to each other via some interface, whether indirectly coupled or communicatively coupled to devices or units, whether electrically, mechanically, or otherwise.
The units described above as separate components may or may not be physically separate, and components shown as units may or may not be physical units; can be located in one place or distributed to a plurality of network units; some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may be separately used as one unit, or two or more units may be integrated in one unit; the integrated units may be implemented in hardware or in hardware plus software functional units.
Those of ordinary skill in the art will appreciate that: all or part of the steps for implementing the above method embodiments may be implemented by hardware related to program instructions, and the foregoing program may be stored in a computer readable storage medium, where the program, when executed, performs steps including the above method embodiments; and the aforementioned storage medium includes: a mobile storage device, a Read Only Memory (ROM), a magnetic disk or an optical disk, or the like, which can store program codes.
Alternatively, the integrated units described above may be stored in a computer readable storage medium if implemented in the form of software functional modules and sold or used as a stand-alone product. Based on such understanding, the technical solutions of the embodiments of the present application may be essentially or partially contributing to the related art, and the computer software product may be stored in a storage medium, and include several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a removable storage device, a ROM, a magnetic disk, or an optical disk.
The foregoing is merely an embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (6)
1. A digital beam forming, DBF, space-borne synthetic aperture radar, SAR, system internal calibration device, comprising: the device comprises an internal calibration module, a data fusion module, a frequency modulation signal generation module and an antenna array module;
the internal calibration module receives the calibration signal, converts the frequency of the calibration signal and outputs the frequency-converted calibration signal; the scaled signal comprises: transmitting a second scaling signal of the scaling mode;
the data fusion module receives the frequency-converted calibration signal, converts the frequency-converted calibration signal into a digital calibration signal and calibrates according to the digital calibration signal;
the frequency modulation signal generation module is used for generating a linear frequency modulation signal;
the antenna array module includes: an antenna transceiver unit and an antenna scaling network unit; the antenna transceiver unit comprises a plurality of transceiver components;
in a transmitting calibration mode, the frequency modulation signal generating module transmits the linear frequency modulation signal as a transmitting signal to the antenna receiving and transmitting unit, the antenna receiving and transmitting unit distributes power of the transmitting signal and then outputs the transmitting signal to the antenna calibration network unit through coupling of each receiving and transmitting component, and the antenna calibration network unit synthesizes the power of the transmitting signal which is output by coupling of different receiving and transmitting components to obtain a second calibration signal and transmits the second calibration signal to the internal calibration module.
2. The apparatus of claim 1, wherein the scaling signal comprises: a first scaling signal referencing the scaling pattern;
in the reference calibration mode, the frequency modulation signal generation module transmits the chirp signal as the first calibration signal to the internal calibration module.
3. The apparatus of claim 1, wherein the apparatus further comprises: a DBF receiving and processing module;
the internal calibration module is used for receiving the linear frequency modulation signal in a receiving calibration mode and sending the linear frequency modulation signal to the antenna array module as a third calibration signal;
the antenna array module amplifies the third calibration signal and transmits the third calibration signal to the DBF receiving and processing module;
the DBF receiving processing module is used for carrying out frequency conversion and amplification on the amplified third scaling signal, converting the third scaling signal into a digital scaling signal and scaling according to the digital scaling signal.
4. The apparatus of claim 3, wherein the antenna array module comprises: an antenna transceiver unit and an antenna scaling network unit;
the antenna calibration network unit distributes power of the third calibration signal and transmits the third calibration signal to the antenna receiving and transmitting unit;
and the antenna receiving and transmitting unit amplifies and synthesizes the third calibration signal after power distribution and then transmits the third calibration signal to the DBF receiving and processing module.
5. A digital beam forming, DBF, on-board synthetic aperture radar, SAR, system localization method, comprising:
receiving a calibration signal through a internal calibration module, and carrying out frequency conversion on the calibration signal; the scaled signal comprises: transmitting a second scaling signal of the scaling mode;
converting the frequency-converted calibration signal into a digital calibration signal through a data fusion module, and calibrating according to the digital calibration signal;
generating a linear frequency modulation signal through a frequency modulation signal generation module, wherein the linear frequency modulation signal is used for obtaining the scaling signal;
in a transmitting calibration mode, the frequency modulation signal generating module transmits the linear frequency modulation signal as a transmitting signal to an antenna receiving and transmitting unit, the antenna receiving and transmitting unit distributes power of the transmitting signal and then outputs the transmitting signal to an antenna calibration network unit through coupling of each receiving and transmitting component, and the antenna calibration network unit synthesizes the power of the transmitting signals output by coupling of different receiving and transmitting components to obtain a second calibration signal and transmits the second calibration signal to the internal calibration module.
6. The method of claim 5, wherein the method further comprises:
and in a reference calibration mode, transmitting the linear frequency modulation signal as a first calibration signal to the internal calibration module through the frequency modulation signal generation module.
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| CN113659352A (en) * | 2021-07-28 | 2021-11-16 | 中国电子科技集团公司第十四研究所 | Satellite-borne full-polarization broadband phased array antenna |
| CN113917470B (en) * | 2021-12-14 | 2022-06-17 | 成都锐芯盛通电子科技有限公司 | High-efficiency DBF radar and calibration method |
| CN114185016B (en) * | 2022-02-16 | 2022-05-17 | 中国科学院空天信息创新研究院 | Method for measuring and compensating amplitude-phase error between channels of multi-channel satellite-borne SAR (synthetic aperture radar) antenna |
| CN115629363B (en) * | 2022-12-16 | 2023-04-28 | 西安空间无线电技术研究所 | Real-time internal calibration method and device for spaceborne detection radar |
| CN116299246B (en) * | 2023-05-19 | 2023-07-21 | 中国科学院空天信息创新研究院 | Method for evaluating internal calibration precision of synthetic aperture radar system |
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