CN114994678A - Multichannel bistatic SAR (synthetic aperture radar) wireless phase predistortion method and device and electronic equipment - Google Patents
Multichannel bistatic SAR (synthetic aperture radar) wireless phase predistortion method and device and electronic equipment Download PDFInfo
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- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
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- G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
- G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
- G01S13/904—SAR modes
- G01S13/9058—Bistatic or multistatic SAR
Abstract
The invention provides a method, a device and electronic equipment for multi-channel bistatic SAR (synthetic aperture radar) wireless phase predistortion, wherein the method comprises the steps of receiving a transmitting signal of a main satellite radar system for time delay, and simultaneously feeding back the transmitting signal to multi-channel receiving and transmitting channels of the main satellite radar system and an auxiliary satellite radar system to obtain multi-channel receiving and transmitting signals; phase error extraction is carried out on the multichannel receiving and transmitting signals of the main satellite and the auxiliary satellite, direct sampling is carried out, the number of sampling points for different signal phase errors is adjustable, phase errors among channels are weighted and averaged to obtain phase predistortion compensation parameters suitable for the multichannel receiving and transmitting channels of the main satellite and the auxiliary satellite, and the transmitting signals of the main satellite are compensated to obtain transmitting signals with compensation phases; and judging whether the main satellite multichannel transmitting and receiving signals and the auxiliary satellite multichannel transmitting and receiving signals after the phase error compensation meet the main radar system index requirements and the auxiliary satellite radar system index requirements, and continuing to perform iterative phase compensation until the system index requirements are met. The method can effectively ensure the imaging resolution of the double-star interference, thereby realizing the improvement of the quality of the satellite-borne SAR double-star interference image.
Description
Technical Field
The invention relates to the technical field of radars, in particular to a method and a device for multi-channel bistatic SAR wireless phase predistortion and electronic equipment.
Background
Synthetic Aperture Radar (SAR) is an active microwave imaging Radar that can be mounted on flying platforms such as airplanes, satellites, missiles, etc. The SAR has unique advantages in the application of disaster monitoring, resource exploration, ocean monitoring, environment monitoring, mapping and the like.
Compared with a single-base radar, the bistatic SAR system is a new important radar system, carries the radar on two flying satellites in formation to form a bistatic radar system, and jointly completes tasks such as large-swath high-resolution imaging, ground elevation measurement, ocean current speed measurement, ground moving target monitoring and the like; the double-satellite formation is realized by transmitting signals by a main satellite and simultaneously receiving signals by the main satellite and an auxiliary satellite. However, the primary satellite and the secondary satellite use a one-transmitting-two-receiving working mode, so that on one hand, a phase error caused by a crystal oscillator frequency error exists in the azimuth direction and is accumulated along with time; on the other hand, since the transmitting phase noise and the receiving phase noise are uncorrelated, the low-frequency phase noise component cannot be cancelled as in the case of a single station, and the phase error of the echo signal generated by the bistatic SAR system affects the imaging focusing and the interference phase precision.
The predistortion method of the bistatic SAR system at present has the following two methods: the method comprises the steps of respectively testing the two stars through a system wireless predistortion method to obtain phase error curves of a multi-channel receiving and transmitting channel of each radar system, and then respectively carrying out phase error predistortion compensation on the receiving and transmitting channel of the satellite, and carrying out system phase error predistortion compensation on the two stars through a wired predistortion method of a bistatic SAR system. The former method has the limitation that only phase errors of respective system transceiving paths can be detected, and the bistatic SAR system needs to be tested and analyzed respectively, which is different from the actual working state, and increases difficulty in post-imaging interference processing. The latter method considers the actual on-orbit working state of the double star when measuring the phase error, but the linear frequency modulation signal does not pass through a complete bistatic SAR system transceiving path, and the phase error obtained by the wired predistortion test method contains an antenna array surface part and influences the accuracy of phase error compensation.
Therefore, it is necessary to provide a multi-channel bistatic SAR wireless phase predistortion method, which can achieve a good predistortion effect for the transmit-receive signals of all channels of the bistatic SAR, and effectively ensure the imaging resolution and the imaging quality of the bistatic SAR interference, thereby achieving the improvement of the bistatic SAR interference image quality.
Disclosure of Invention
In order to solve the technical problem, the invention provides a method and a device for multi-channel bistatic SAR wireless phase predistortion and electronic equipment.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
according to a first aspect of some embodiments of the present disclosure, there is provided a multi-channel bistatic SAR wireless phase predistortion method, including: receiving a transmitting signal of a main satellite radar system, carrying out time delay, and simultaneously feeding back the delayed transmitting signal to a multi-channel transmitting and receiving channel of the main satellite radar system and a multi-channel transmitting and receiving channel of an auxiliary satellite radar system to obtain multi-channel transmitting and receiving signals of the main satellite and the auxiliary satellite; the phase errors of the multichannel transceiving paths of the main and auxiliary satellite radar systems are obtained on the basis of a double-threshold detection method for the multichannel transceiving signals of the main and auxiliary satellites, the phase errors are directly sampled, the number of sampling points for the phase errors of different signals is adjustable, and phase errors among the channels are weighted and averaged to obtain phase predistortion compensation parameters suitable for the multichannel transceiving paths of the main and auxiliary satellite radar systems; performing phase error compensation on signals transmitted by the main satellite radar system based on the phase predistortion compensation parameters to obtain error-compensated main and auxiliary satellite multi-channel transceiving signals; and judging whether the main satellite multi-channel receiving and transmitting signals after the phase error compensation meet the index requirements of the main satellite radar system and the auxiliary satellite radar system, if not, continuing to iteratively compensate the phase errors corresponding to the main satellite multi-channel receiving and transmitting signals after the phase error compensation on the transmitting signals of the main satellite radar system until the index requirements of the main satellite radar system and the auxiliary satellite radar system are met.
Furthermore, the transmitting signal of the main satellite radar system is a linear frequency modulation signal radiated from the antenna array of the main satellite, and the multi-channel transmitting and receiving signals of the main satellite and the auxiliary satellite are realized by the signal feedback module and the receiving module, so that the transmitting signal of the main satellite and the transmitting signal of the auxiliary satellite simultaneously pass through the complete transmitting and receiving channel of the main satellite radar system and the auxiliary satellite radar system.
Further, the time delay is realized by a delay device with a signal time delay function, and the delay device comprises an analog delay device and a digital delay device.
Further, the phase error of the multi-channel transceiving channel of the main and auxiliary satellite radar systems is obtained based on a double-threshold detection method, which comprises the following steps: and multiplying the main satellite transmitting and receiving signal and the auxiliary satellite transmitting and receiving signal by the conjugate complex number of the ideal reference signal to obtain a signal to be detected, and determining the phase error of the signal to be detected by using the double-threshold detection method.
Further, carry out direct sampling to phase error, to different signal phase error sampling point adjustable, carry out the phase error of weighted average between the passageway and obtain the phase place predistortion compensation parameter that is applicable to main, supplementary star multichannel receiving and dispatching route, include:
the extracted phase errors among the channels are used for weighted average to obtain a phase error coefficient suitable for the bistatic SAR, and the phase error coefficient meets the following requirements:
b n =b n_i *A i ，n=1,…,128,…256,…512
1=∑ i=1 A i ，i=1,…,k
wherein the content of the first and second substances,b n representing the phase error coefficient after the weighted average,b n_i is shown asiThe phase error coefficients extracted by the channels,A i is shown asiThe weight value of the channel is set to be,krepresenting the number of channels of the radar system;
further, phase compensation is performed on the signals transmitted by the main satellite radar system based on the phase predistortion compensation parameters to obtain the transmitted signals with the compensation phase, and the method comprises the following steps:
carrying out 1024-point interpolation by utilizing the phase error coefficient after weighting average among channels to obtain a compensation phaseϕ err_all (t) Further obtain the main satellite transmitting signal with the compensated phaseS M-PreT (t) The main satellite transmitting signal with the compensation phase satisfies the following conditions:
S M-PreT (t)=rect(t∕T p )∗exp(j𝜋k r (t) 2 -jϕ err_all (t))
wherein the content of the first and second substances,rect() A function of a rectangle is represented by the following equation,tin order to be the time of sampling,T p the pulse width of the signal transmitted for the master satellite,k r in order to be the slope of the frequency modulation,jis the imaginary symbol;
further, whether the main satellite multi-channel receiving and transmitting signals after the phase error compensation meet the main satellite radar system index requirements and the auxiliary satellite radar system index requirements or not is judged, wherein the main satellite multi-channel receiving and transmitting signals after the phase error compensation are subjected to pulse compression analysis based on fast Fourier transform, and whether the main satellite radar system index requirements and the auxiliary satellite radar system index requirements are met or not is judged by taking the 3dB width, the 3dB broadening coefficient, the peak side lobe ratio and the integral side lobe ratio as evaluation basis;
further, the iterative compensation is carried out on the phase errors corresponding to the main satellite radar system transmitting signals and the auxiliary satellite multi-channel transmitting and receiving signals after the phase error compensation until the main satellite radar system transmitting signals and the auxiliary satellite radar system index requirements are met, the iterative compensation is carried out on the main satellite radar system transmitting signals and the auxiliary satellite radar system transmitting signals, the obtained phase errors are written into a main satellite frequency modulation signal source, the phase errors are added into ideal linear frequency modulation signals when the main satellite generates the linear frequency modulation signals, and the transmitting signals which meet the main satellite radar system index and the auxiliary satellite radar system index and have compensation phases are obtained;
the invention also provides a multi-channel bistatic SAR wireless phase predistortion device, which comprises:
the signal feedback module is used for receiving the linear frequency modulation signals transmitted by the main satellite radar system by using the horn antenna, carrying out time delay on the main satellite transmitting signals by using digital delay equipment and transmitting the delayed main satellite transmitting signals by using the horn antenna;
the main satellite radar system and the auxiliary satellite radar system are used for receiving the linear frequency modulation signals which are sent by the signal feedback module and subjected to time delay, and obtaining main satellite multi-channel receiving and sending signals and auxiliary satellite multi-channel receiving and sending signals;
the determining module is used for determining phase errors of the primary satellite multi-channel transceiving signals and the secondary satellite multi-channel transceiving signals and determining phase predistortion compensation parameters according to the phase errors;
and the compensation module is used for carrying out iterative phase compensation on the primary satellite multi-channel transceiving signals and the secondary satellite multi-channel transceiving signals according to the phase predistortion compensation parameters until the system index requirements are met.
The present invention also provides an electronic device comprising:
the device comprises a memory, a processor and a computer program which is stored on the memory and can run on the processor, and is characterized in that the processor realizes the multi-channel bistatic SAR wireless phase predistortion method provided by the invention when executing the computer program.
Compared with the prior art, the multichannel bistatic SAR wireless phase predistortion method, the device and the electronic equipment have the following beneficial effects:
(1) the method obtains the main and auxiliary satellite multichannel phase predistortion compensation parameters through a one-transmission and multi-reception ground test mode, and has the advantages of accuracy, high efficiency, low hardware cost and wide application range;
(2) according to the method, the phase errors of the main and auxiliary satellite multichannel receiving and transmitting signals are directly sampled, the number of sampling points for different signal phase errors is adjustable, the phase errors among the channels are weighted and averaged to obtain phase predistortion compensation parameters suitable for the main and auxiliary satellite multichannel receiving and transmitting channels, and the multichannel phase predistortion effect of the double-base satellite-borne synthetic aperture radar system can be improved;
(3) the phase error between the channels meeting the index requirements of the main satellite radar system and the auxiliary satellite radar system is completely controlled by the FPGA program of the main satellite frequency modulation source and added to an ideal linear frequency modulation signal, no additional hardware circuit resource is required to be added, the whole process is simple and convenient to realize, and the universality is high;
(4) the iterative compensation method of the phase error provided by the invention is that the phase error weight coefficient is set according to the phase error size before the predistortion of each channel, if the phase error compensation curve obtained according to the initial weight coefficient can not ensure that the receiving and transmitting signals of each channel meet the system index requirements, the weight coefficient of the phase error between the channels is adjusted according to the residual phase error value between the channels after the predistortion, the iterative compensation is continuously carried out on the transmitting signals of the main satellite radar system until the index requirements of the double-base satellite-borne synthetic aperture radar system are met, and the improvement of the interference image quality of the double-base satellite-borne synthetic aperture radar system is realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, the drawings in the following description are only one embodiment of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic flowchart of a multi-channel bistatic SAR wireless phase predistortion method according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a bistatic SAR according to an embodiment of the present invention;
fig. 3 is a schematic flow chart of an implementation of a multi-channel bistatic SAR wireless phase predistortion method according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a multi-channel bistatic SAR wireless phase predistortion apparatus according to an embodiment of the present invention;
fig. 5 is a schematic diagram of a hardware structure of an electronic device of a wireless phase predistortion apparatus according to an embodiment of the invention.
Detailed Description
In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only one embodiment of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the embodiment of the invention, the transmitting signal of the main satellite radar system is received and time-delayed, and the time-delayed signal is simultaneously fed back to the multi-channel receiving channels of the main satellite radar system and the auxiliary satellite radar system to obtain the multi-channel receiving and transmitting signals of the main satellite and the auxiliary satellite; the method comprises the steps of extracting phase errors of multichannel transmitting and receiving signals of a main satellite and an auxiliary satellite, directly sampling the phase errors, obtaining phase predistortion compensation parameters suitable for multichannel transmitting and receiving channels of the main satellite and the auxiliary satellite by weighting and averaging the phase errors among the channels aiming at the adjustable sampling points of the phase errors of different signals, and compensating transmitting signals of the main satellite based on the phase predistortion compensation parameters to obtain multichannel transmitting and receiving signals of the main satellite and the auxiliary satellite with compensation phases; and judging whether the main satellite multi-channel receiving and transmitting signals after the phase error compensation meet the main satellite radar system index requirements and the auxiliary satellite radar system index requirements or not, and continuing to perform iterative phase compensation aiming at different channels of the main satellite and the auxiliary satellite which are not met until the main satellite radar system index requirements and the auxiliary satellite radar system index requirements are met.
Referring to fig. 1, fig. 1 is a schematic flow chart of a multi-channel bistatic SAR wireless phase predistortion method according to an embodiment of the present invention, the method mainly includes the following steps:
step 102: and receiving the transmitting signals of the main satellite radar system, delaying the time, and simultaneously feeding the delayed transmitting signals back to the multichannel transmitting and receiving channels of the main satellite radar system and the auxiliary satellite radar system to obtain multichannel transmitting and receiving signals of the main satellite and the auxiliary satellite.
In this embodiment, the transmitting signal of the master satellite radar system is a chirp signal with a negative chirp slope, the transmitting signal of the master satellite radar system is received by the signal feedback module, and the received chirp signal is delayed by the digital delay device. The digital delay device has a digital adjustable time delay function, and the delayed radar signals are simultaneously fed back to the multichannel receiving and transmitting channels of the main and auxiliary satellite radar systems through the signal power divider to obtain complete multichannel receiving and transmitting signals of the main and auxiliary satellites.
Step 104: and obtaining the phase errors of the multi-channel transceiving channels of the main and auxiliary satellite radar systems based on a double-threshold detection method.
In this embodiment, the main satellite transmitting and receiving signal and the auxiliary satellite transmitting and receiving signal are multiplied by the complex conjugate of the ideal reference signal to obtain a signal to be measured, the phase of the signal to be measured is unwrapped to obtain a phase error curve, and a non-zero part is found by using a double-threshold detection method for the phase error curve to obtain the phase error of the signal to be measured in the pulse width.
Step 106: the phase error is directly sampled, the number of sampling points is adjustable according to different signal phase errors, and the phase errors among channels are weighted and averaged to obtain phase predistortion compensation parameters suitable for a main satellite receiving and transmitting channel and an auxiliary satellite receiving and transmitting channel.
In this embodiment, the extracted phase errors between the channels are used to perform weighted average, so as to obtain a phase error coefficient suitable for the bistatic SAR, and satisfy:
b n =b n_i *A i ，n=1,…,128,…256,…512
1=∑ i=1 A i ，i=1,…,k
wherein the content of the first and second substances,b n representing the phase error coefficient after the weighted average,b n_i represents the phase error coefficient extracted by the ith channel,A i the weighting value of the ith channel is represented, and k represents the number of channels of the radar system;
step 108: and performing phase error compensation on the transmitting signal of the main satellite radar system based on the phase predistortion compensation parameter to obtain the error-compensated main satellite and auxiliary satellite multichannel transmitting and receiving signals.
Using inter-channel weighted average of the phasesCarrying out 1024-point interpolation on the bit error coefficient to obtain a compensation phaseϕ err_all (t) Further obtain the main satellite transmitting signal with the compensated phaseS M-PreT (t) The main satellite transmitting signal with the compensation phase satisfies the following conditions:
S M-PreT (t)=rect(t∕T p )∗exp(j𝜋k r (t) 2 -jϕ err_all (t))
wherein the content of the first and second substances,rect() A function of a rectangle is represented by,tin order to be the time of sampling,T p the pulse width of the signal transmitted for the master satellite,k r in order to be the slope of the frequency modulation,jis the imaginary symbol;
step 110: and judging whether the main and auxiliary satellite multi-channel receiving and transmitting signals after the phase error compensation meet the index requirements of the main and auxiliary satellite radar systems, if not, adjusting the weight coefficient of the phase error between the channels, and continuously performing iterative compensation on the transmitting signals of the main satellite radar system until the index requirements of the main and auxiliary satellite radar systems are met.
In this embodiment, first, the main and auxiliary satellite multichannel transmission and reception signals after phase error compensation are subjected to pulse compression analysis based on fast fourier transform, and whether the main and auxiliary satellite radar system index requirements are met is judged by taking the 3dB width, the 3dB broadening coefficient, the peak sidelobe ratio and the integral sidelobe ratio as evaluation criteria.
And if the phase error curve obtained according to the initial phase error coefficient can not ensure that the transmitting and receiving signals of each channel meet the index requirements of the main satellite radar system and the auxiliary satellite radar system, adjusting the phase error coefficient of the phase error between the channels according to the residual phase error value between the pre-distorted channels, and continuing to perform iterative compensation on the transmitting signals of the main satellite radar system until the index requirements of the main satellite radar system and the auxiliary satellite radar system are met.
Fig. 2 is a schematic structural diagram of a bistatic SAR according to an embodiment of the present invention, and as shown in fig. 2, the bistatic SAR includes a main satellite 20, an auxiliary satellite 21, and a signal feedback device 22; the main satellite 20 is used for transmitting radar signals and receiving signals after time delay; the auxiliary satellite 21 is used for receiving the radar signal transmitted by the main satellite after the time delay; and the signal feedback equipment 22 is used for receiving the radar signals transmitted by the main satellite, delaying the signals by the digital delay equipment after the power is attenuated, and transmitting the signals to the main satellite and the auxiliary satellite through the two horn antennas. The main star 20 includes: a main Satellite GNSS (Global Navigation Satellite System) taming module 201, a main Satellite reference frequency source 202, a main Satellite frequency modulation signal source 203, a main Satellite internal calibrator 204, a main Satellite synchronous transceiver 205, a main Satellite synchronous antenna 206, a main Satellite receiver 207, a main Satellite data former 208 and a main Satellite active phased array antenna 209. The satellite 21 includes: a satellite GNSS taming module 211, a satellite reference frequency source 212, a satellite fm signal source 213, a satellite internal calibrator 214, a satellite synchronization transceiver 215, a satellite synchronization antenna 216, a satellite receiver 217, a satellite data former 218, and a satellite active phased array antenna 219, wherein:
a Master satellite GNSS taming module 201 for providing a time frequency signal to a Master satellite reference frequency source 202;
a master satellite reference frequency source 202, configured to generate a plurality of operating frequency signals with reference to the frequency provided by the master satellite GNSS taming module 201 to provide to a master satellite frequency modulation signal source 203;
a master satellite frequency modulation signal source 203, configured to provide a chirp signal to the master satellite internal calibrator 204, the master satellite synchronous transceiver 205, and the master satellite active phased array antenna 209;
a master intra-satellite scaler 204 for scaling the signal transmitted by the synchronous transceiver of the master satellite 20;
a primary satellite synchronous transceiver 205 for transmitting or receiving a phase synchronization signal to the secondary satellite 21 through a primary satellite synchronous antenna 206;
a primary satellite synchronization antenna 206 for transmitting or receiving a phase synchronization signal to the secondary satellite 21;
a master satellite receiver 207 for sending radar echo signals and two-satellite phase synchronization signals to a master satellite data former 208;
a master satellite data former 208 for performing data processing on the received signals;
a master active phased array antenna 209 for transmitting and receiving radar signals;
an assisted satellite GNSS taming module 211 for providing a time-frequency signal to an assisted satellite reference frequency source 212;
a satellite reference frequency source 212, configured to generate a plurality of operating frequency signals based on the frequency provided by the satellite GNSS taming module 211 for providing to the satellite fm signal source 213;
a satellite frequency modulation signal source 213, configured to provide a chirp signal to the satellite internal calibrator 214 and the satellite synchronization transceiver 215;
an intra-satellite calibrator 214 configured to calibrate a signal transmitted by the auxiliary satellite synchronization transceiver 215 of the auxiliary satellite 21;
a secondary satellite synchronization transceiver 215 for transmitting or receiving a phase synchronization signal to the primary satellite 20 through a secondary satellite synchronization antenna 216;
a secondary satellite synchronization antenna 216 for transmitting or receiving a phase synchronization signal to the secondary satellite 21;
a satellite receiver 217 for sending signals to a satellite data former 218;
a satellite data former 218 for performing data processing on the received signals;
a satellite active phased array antenna 219 for transmitting and receiving radar signals;
the signal feedback device 22 includes:
the main satellite horn antenna 221 is used for receiving a main satellite radar transmission signal and transmitting a delayed signal;
a circulator 222 for rf signal reception and transmission port conversion;
the attenuator 223 is used for attenuating the power of the signal transmitted by the main satellite radar and ensuring the input power of the digital delay equipment;
the digital delay equipment 224 is used for performing signal delay output on the main satellite radar transmitting signal;
a power divider 225, configured to simultaneously send the delayed radar transmission signal to the main-satellite horn antenna 221 and the auxiliary-satellite horn antenna 226;
and the auxiliary satellite horn antenna 226 is configured to transmit the delayed signal to the auxiliary satellite active phased array antenna 219.
The same batch of horn antennas with the same gain are used for the horn antennas of the main satellite 20 and the auxiliary satellite 21, so that the phase errors of multiple satellites can be reduced as much as possible, the complexity of phase synchronization error extraction and compensation can be further simplified, and the accuracy and the reliability of wireless phase predistortion are improved.
Fig. 3 is a schematic flow chart of an implementation process of the multi-channel bistatic SAR wireless phase predistortion method according to the embodiment of the present invention, and as shown in fig. 3, the bistatic SAR multi-channel phase error compensation can be implemented by the following steps:
s301, extracting phase errors of multichannel primary and secondary satellite transmitting and receiving signals without phase predistortion compensation;
s302, directly sampling the phase error, adjusting the number of sampling points for different signal phase errors, and performing phase error compensation on the main satellite transmitting signal based on the phase error after weighting and averaging among channels;
s303, obtaining multichannel primary and secondary satellite receiving and transmitting signals after the phase errors of the primary and secondary satellites are compensated, and performing pulse compression;
s304, performing pulse compression analysis based on fast Fourier transform on the error-compensated main satellite multi-channel transmitting and receiving signals and the auxiliary satellite multi-channel transmitting and receiving signals, judging whether the main satellite radar system index requirements and the auxiliary satellite radar system index requirements are met or not by taking the 3dB width, the 3dB broadening coefficient, the peak side lobe ratio and the integral side lobe ratio as evaluation basis, if so, ending, and if not, performing S305;
s305, carrying out phase error extraction iteration on the multichannel primary and secondary satellite receiving and transmitting signals after the phase error compensation, adjusting the phase error coefficient of each channel, and returning to the step S302.
It should be noted that, when the phase errors between the primary and secondary satellite channels are weighted and averaged, the phase error coefficients between different channels need to be iteratively learned to determine a group of optimal combinations, so as to satisfy the requirement that the dual-satellite multi-channel transmit-receive signals can satisfy the index requirements of the primary and secondary satellite radar systems.
It should be noted that the algorithm for performing pulse compression on the multi-channel primary and secondary satellite transceiving signals after the phase error predistortion compensation includes, but is not limited to, a fast fourier transform method, and a frequency analysis method and a direct correlation method may also be selected.
Referring to fig. 4, fig. 4 is a schematic structural diagram of a multi-channel bistatic SAR wireless phase predistortion apparatus according to an embodiment of the present invention, the apparatus includes:
the signal feedback module 401 receives the chirp signal transmitted by the primary satellite radar system by using a horn antenna, performs time delay on the primary satellite transmission signal by using digital delay equipment, and transmits the delayed primary satellite transmission signal by using the horn antenna;
the receiving module 402 is used for receiving the linear frequency modulation signals after time delay sent by the signal feedback module by the primary and secondary satellite radar systems to obtain primary satellite multi-channel transceiving signals and secondary satellite multi-channel transceiving signals;
a determining module 403, configured to determine phase errors of the primary satellite multichannel transceiving signals and the secondary satellite multichannel transceiving signals, and determine phase predistortion compensation parameters according to the phase errors;
and the compensation module 404 is configured to perform iterative phase compensation on the primary satellite multichannel transmitting and receiving signal and the secondary satellite multichannel transmitting and receiving signal according to the phase predistortion compensation parameter until the index requirements of the primary and secondary satellite radar systems are met.
Referring to fig. 5, fig. 5 is a schematic diagram illustrating a hardware structure of an electronic device according to the present invention.
The electronic device described in this embodiment includes:
a memory 51, a processor 52 and a computer program stored on the memory 51 and executable on the processor 52, the processor 52 when executing the computer program implementing the multi-channel bistatic SAR wireless phase predistortion method described in the embodiments.
Further, the electronic device further includes:
at least one input device 53; at least one output device 54.
The memory 51, processor 52, input device 53 and output device 54 are connected by a bus 55.
The input device 53 may be a camera, a touch panel, a physical button, or a mouse. The output device 54 may specifically be a display screen.
The Memory 51 may be a high-speed Random Access Memory (RAM) Memory or a non-volatile Memory (non-volatile Memory), such as a disk Memory. The memory 51 is used for storing a set of executable program codes, and the processor 52 is coupled to the memory 51.
In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described embodiments are merely illustrative, and for example, the division of the modules is merely a logical division, and an actual implementation may have another division, for example, a plurality of modules or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication link may be through some interfaces, and the indirect coupling or communication link of the modules may be in an electrical, mechanical or other form.
The modules described as separate parts may or may not be physically separate, and parts displayed as modules may or may not be physical modules, may be located in one place, or may be distributed on a plurality of network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
In addition, functional modules in the embodiments of the present invention may be integrated into one processing module, or each of the modules may exist alone physically, or two or more modules are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode.
It should be noted that for simplicity and convenience of description, the above-described method embodiments are shown as a series of combinations of acts, but it should be understood by those skilled in the art that the present invention is not limited by the order of acts, as some steps may occur in other orders or concurrently in accordance with the invention. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred and that no acts or modules are necessarily required of the invention.
The above description is provided for the method, apparatus, electronic device and storage medium for wireless phase predistortion for a multi-channel bistatic space-borne synthetic aperture radar system, and for those skilled in the art, there may be variations in the specific implementation and application scope according to the ideas of the embodiments of the present invention.
Claims (10)
1. A multi-channel bistatic SAR wireless phase predistortion method is characterized by comprising the following steps:
receiving a transmitting signal of a main satellite radar system, carrying out time delay, and simultaneously feeding the delayed transmitting signal back to a multi-channel transmitting and receiving channel of the main satellite radar system and a multi-channel transmitting and receiving channel of a secondary satellite radar system to obtain multi-channel transmitting and receiving signals of a main satellite and a secondary satellite;
the phase errors of the multichannel transceiving paths of the main and auxiliary satellite radar systems are obtained on the basis of a double-threshold detection method for the multichannel transceiving signals of the main and auxiliary satellites, the phase errors are directly sampled, the number of sampling points for the phase errors of different signals is adjustable, and phase errors among the channels are weighted and averaged to obtain phase predistortion compensation parameters suitable for the multichannel transceiving paths of the main and auxiliary satellite radar systems;
performing phase error compensation on a transmitting signal of the main satellite radar system based on the phase predistortion compensation parameter to obtain error-compensated multi-channel transmitting and receiving signals of the main satellite and the auxiliary satellite;
and judging whether the main satellite multi-channel receiving and transmitting signals after the phase error compensation meet the index requirements of the main satellite radar system and the auxiliary satellite radar system, if not, continuing to iteratively compensate the transmitting signals of the main satellite radar system by the phase errors corresponding to the main satellite multi-channel receiving and transmitting signals after the phase error compensation until the index requirements of the main satellite radar system and the auxiliary satellite radar system are met.
2. The multi-channel bistatic SAR wireless phase predistortion method of claim 1, wherein: the transmitting signal of the main satellite radar system is a linear frequency modulation signal radiated from a main satellite antenna array surface, and the multi-channel transmitting and receiving signals of the main satellite and the auxiliary satellite are realized by a signal feedback module and a receiving module, so that the transmitting signal of the main satellite radar system simultaneously passes through a complete transmitting and receiving channel of the main satellite radar system and the auxiliary satellite radar system.
3. The multi-channel bistatic SAR wireless phase predistortion method of claim 2, wherein: the time delay is realized by a delay device with a signal time delay function, and the delay device comprises an analog delay device and a digital delay device.
4. The multi-channel bistatic SAR wireless phase predistortion method of claim 1, characterized in that: the obtaining of the phase errors of the multi-channel transceiving channels of the main and auxiliary satellite radar systems based on the double-threshold detection method comprises the following steps: and multiplying the multi-channel transceiving signals of the main satellite and the auxiliary satellite by the conjugate complex number of the ideal reference signal to obtain a signal to be detected, and determining the phase error of the signal to be detected by using the double-threshold detection method.
5. The multi-channel bistatic SAR wireless phase predistortion method of claim 4, characterized in that: carry out direct sampling to phase error, to different signal phase error sampling point number adjustable, carry out the phase error of weighing between the passageway and average and obtain the phase place predistortion compensation parameter that is applicable to main, auxiliary star multichannel receiving and dispatching route, include: the extracted phase errors among the channels are used for weighted average to obtain a phase error coefficient suitable for the bistatic SAR, and the following requirements are met:
b n =b n_i *A i ，n=1,…,128,…256,…512
1=∑ i=1 A i ，i=1,…,k
wherein the content of the first and second substances,b n representing the phase error coefficient after the weighted average,b n_i is shown asiThe phase error coefficients extracted by the channels,A i is shown asiThe weight value of the channel is set to be,krepresenting the number of channels of the radar system.
6. The multi-channel bistatic SAR wireless phase predistortion method of claim 5, characterized in that: the phase compensation is carried out on the transmitting signal of the main satellite radar system based on the phase predistortion compensation parameter to obtain the transmitting signal with a compensation phase, and the method comprises the following steps:
carrying out 1024-point interpolation by using the phase error coefficient after weighting average among channels to obtain a compensation phaseϕ err_all (t) Further obtain the main satellite transmitting signal with the compensated phaseS M-PreT (t) The main satellite transmitting signal with the compensation phase satisfies the following conditions:
S M-PreT (t)=rect(t∕T p )∗exp(j𝜋k r (t) 2 -jϕ err_all (t))
wherein the content of the first and second substances,rect() A function of a rectangle is represented by,tin order to be the time of sampling,T p the pulse width of the signal transmitted for the master satellite,k r in order to be the slope of the frequency modulation,jis the imaginary symbol.
7. The multi-channel bistatic SAR wireless phase predistortion method of claim 1, characterized in that: judging whether the main satellite multichannel receiving and transmitting signals and the auxiliary satellite multichannel receiving and transmitting signals after the phase error compensation meet the main satellite radar system index requirements and the auxiliary satellite radar system index requirements comprises the following steps: and performing pulse compression analysis based on fast Fourier transform on the multichannel transmitting and receiving signals of the main satellite and the auxiliary satellite after error compensation, and judging whether the system index requirements of the main satellite radar and the auxiliary satellite radar are met or not by taking the 3dB width, the 3dB broadening coefficient, the peak sidelobe ratio and the integral sidelobe ratio as evaluation basis.
8. The multi-channel bistatic SAR wireless phase predistortion method according to one of claims 1 to 7, characterized in that: and continuously carrying out iterative compensation on the transmitting signals of the main satellite radar system by the phase errors corresponding to the main satellite multichannel transmitting and receiving signals after the phase error compensation until the index requirements of the main satellite radar system and the auxiliary satellite radar system are met, and the iterative compensation comprises the following steps: and writing the obtained phase error meeting the index requirements of the main and auxiliary satellite radar systems into a main satellite frequency modulation signal source, and adding the phase error into an ideal linear frequency modulation signal when the main satellite generates the linear frequency modulation signal to obtain a transmitting signal meeting the index of the main and auxiliary satellite radar systems and having a compensation phase.
9. A multi-channel bistatic SAR wireless phase predistortion device, comprising:
the signal feedback module is used for receiving the linear frequency modulation signals transmitted by the main satellite radar system by using the horn antenna, carrying out time delay on the main satellite transmitting signals by using digital delay equipment and transmitting the delayed main satellite transmitting signals by using the horn antenna;
the main satellite radar system and the auxiliary satellite radar system are used for receiving the linear frequency modulation signals which are sent by the signal feedback module and subjected to time delay, and obtaining main satellite multi-channel receiving and sending signals and auxiliary satellite multi-channel receiving and sending signals;
the determining module is used for determining phase errors of the primary satellite multi-channel transceiving signals and the secondary satellite multi-channel transceiving signals and determining phase predistortion compensation parameters according to the phase errors;
and the compensation module is used for carrying out iterative phase compensation on the primary satellite multi-channel transmitting and receiving signals and the secondary satellite multi-channel transmitting and receiving signals according to the phase predistortion compensation parameters until the index requirements of the primary and secondary satellite radar systems are met.
10. An electronic device, comprising: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein: the processor, when executing the computer program, implements the multi-channel bistatic SAR wireless phase predistortion method of any of claims 1 to 8.
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| CN115575956A (en) * | 2022-12-07 | 2023-01-06 | 中国科学院空天信息创新研究院 | Detection and compensation method for phase synchronization interference signal of formation SAR satellite |
| CN116148802A (en) * | 2023-04-24 | 2023-05-23 | 中国科学院空天信息创新研究院 | Bistatic SAR phase synchronization anti-interference method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115575956A (en) * | 2022-12-07 | 2023-01-06 | 中国科学院空天信息创新研究院 | Detection and compensation method for phase synchronization interference signal of formation SAR satellite |
| CN115575956B (en) * | 2022-12-07 | 2023-03-10 | 中国科学院空天信息创新研究院 | Detection and compensation method for phase synchronization interference signal of formation SAR satellite |
| CN116148802A (en) * | 2023-04-24 | 2023-05-23 | 中国科学院空天信息创新研究院 | Bistatic SAR phase synchronization anti-interference method |
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