CN114690145A - Microwave photon radar - Google Patents

Abstract

The invention discloses a microwave photon radar, comprising: and the radar signal generation module is used for generating a narrow-band radar signal, converting the narrow-band radar signal into two paths of optical signals and outputting the two paths of optical signals. And the radar signal transmitting module is used for receiving one path of optical signal and converting the optical signal into a radio frequency antenna signal to be transmitted. And the reference signal delay module is used for receiving another path of optical signal and carrying out delay processing to obtain a reference signal. And the receiving and mixing module is used for receiving the reference signal and the echo signal and performing deskew mixing receiving to obtain the dot frequency signal. And the analysis processing module is used for receiving the dot frequency signals to perform processing analysis. The optical signal is used for multiple cycles, the gapless and repeated multiple delay is automatically realized, and the optical switch can be used in the delay to switch different delay amounts participating in the cycle, so that the length of the optical fiber ring is controlled, the cycle period can be set, and the function of the optical switch is replaced. On the basis of the adjustable controllable optical delay line, the microwave photon radar can realize non-blind area and non-repeated detection and mapping in the maximum range.

Description

Microwave photon radar

Technical Field

The invention belongs to the technical field of radars, and particularly relates to a microwave photon radar.

Background

The microwave photon radar generates an ultra-wideband radar signal by means of an optical technology, and has the functions of high resolution, clutter resistance and the like. In order to process ultra-wideband radar signals, a deskew frequency mixing method is often adopted, so that the frequency of receiving and processing intermediate-frequency signals can be effectively reduced, and the pressure of back-end processing analog-to-digital conversion is reduced.

The factors determining the frequency of the if signal received by the deskew mixing method are mainly the radar signal bandwidth, the pulse time width, and the time difference between the echo and the transmitted signal.

Although the radar signal bandwidth B is adjustable, the bandwidth B is not suitable for being adjusted to be smaller, and the technical advantages of the ultra-wideband of the microwave photon radar are lost. The pulse width T can be adjusted to the maximum as possible, but if set too large, the pulse width T will exceed the target detection range unit, which is not favorable for detection. Therefore, in the case where the two factors are basically determined, the factor for determining the reception intermediate frequency is the detection distance R (corresponding to the delay τ). The smaller R is, the smaller the frequency of the obtained receiving intermediate frequency signal is, and conversely, the larger R is, the larger the frequency of the obtained receiving intermediate frequency signal is.

The solution formed at present in China is to set a certain delay tau to a mixed reference signal at a receiving end by using an optical fiber delay line₀(corresponds to R)₀) Thus indirectly reducing the R value and then fixing tau₀Counting in, forming (R-R)₀) To solve the actual detection distance R value.

In the prior art, the range of the microwave photon radar receiving processing caused by large bandwidth is relatively small, and for a target with unknown distance, if a delay line with fixed length or delay quantity is adopted, a radar detection result cannot be obtained. In order to realize the detection of the target with unknown distance, a method of continuously expanding the measuring range by adopting a multi-delay line is more suitable, so that a plurality of small measuring ranges can be spliced to form a large measuring range without a blind area and a detection interval.

The prior art also provides a method for shunting the delay line, which essentially combines different delay lines in parallel, divides a reference signal into a plurality of paths of delay, can form different ranges and meets the requirements of different detection ranges. However, this approach has several problems: 1. the multi-path delay structure is complex, each path of delay line needs a modulator and a photoelectric converter, the basic idea is still limited to a fixed delay line structure, and only parallel combination is carried out on the delay line structure, 2, the delay structure does not solve the problem that reference signals are continuous, have no interval and have no repetition, because the multi-stage delay line is a parallel delay structure, the delay amount of the delay line is fixed, each group of delay lines corresponds to a fixed range, and does not necessarily form a non-detection blind zone with the detection range of an original radar, 3, the method needs to carry out shunt processing on the reference signals, and extra insertion loss is increased, 4, the method needs to carry out shunt processing on echo signals, and extra insertion loss is also increased. In addition, the automatic light cycle time delay structure mentioned in the prior art only has an automatic cycle function, but does not have a controllable and adjustable function, so that the wide application of the incremental delay structure is severely limited, and the practicability is lacked.

In summary, for the requirement of the microwave photonic radar reference signal delay, in order to solve the problem of limited processing range of the microwave photonic radar, a technical scheme that the microwave photonic reference signal is controllable and adjustable and can realize a large delay amount needs to be designed.

Disclosure of Invention

The technical purpose of the invention is to provide a microwave photon radar to solve the technical problems in the background technology.

In order to solve the problems, the technical scheme of the invention is as follows:

a microwave photonic radar comprising:

the device comprises a radar signal generating module, a radar signal transmitting module, a reference signal delaying module, a receiving frequency mixing module and an analyzing and processing module;

the radar signal generation module is respectively connected with the radar signal emission module and the reference signal delay module through light paths and is used for generating a narrow-band radar signal, converting the narrow-band radar signal into two paths of optical signals and outputting the two paths of optical signals;

the radar signal transmitting module is used for receiving one path of optical signal and converting the optical signal into a radio frequency antenna signal to be transmitted;

the reference signal delay module is used for receiving another optical signal and carrying out delay processing to obtain a reference signal,

the receiving and frequency mixing module is in signal connection with the reference signal delay module and is used for respectively carrying out deskew frequency mixing receiving on the reference signals and the radio frequency radar echoes corresponding to the radio frequency antenna signals to obtain dot frequency signals;

the analysis processing module is used for receiving the dot frequency signals to carry out processing analysis so as to obtain processing information of the microwave photon radar.

Specifically, the radar signal generation module comprises a radar signal generator, a first electro-optical modulator, a laser source and a first optical coupler;

the radar signal generator is in signal connection with the first electro-optical modulator and is used for outputting a narrow-band radar signal to the first electro-optical modulator;

the laser source provides a light source for the first electro-optical modulator;

the first electro-optical modulator is used for receiving the narrow-band radar signal and converting the narrow-band radar signal into an optical signal by matching with the laser source and then outputting the optical signal;

the first optical coupler is used for receiving the optical signal and then dividing the optical signal into two parts which are respectively input to the radar signal transmitting module and the reference signal delay module.

Specifically, the radar signal transmitting module comprises a first photoelectric converter, a first filtering and amplifying submodule, a microwave power amplifier and a radio frequency transmitting antenna;

the first photoelectric converter is used for receiving the optical signal and converting the electrical signal;

the first filtering and amplifying submodule is used for receiving the electric signal and carrying out filtering and amplifying processing;

the microwave power amplifier is used for receiving the filtered and amplified electric signal and amplifying the power;

the radio frequency transmitting antenna is used for converting the electric signal after receiving power amplification into a radio frequency antenna signal to be transmitted.

Specifically, the reference signal delay module comprises a first optical switch, a second optical coupler, a second filtering and amplifying submodule and an adjustable delay line;

the first optical switch is used for receiving another path of optical signal from the radar signal generation module and guiding the optical signal into the second optical coupler;

the second optical coupler and the second filtering amplification sub-module are arranged on a transmission path of the adjustable delay line optical circuit, and the second optical coupler is used for receiving optical signals and is matched with the first optical switch and the second optical switch to enable the optical signals to realize delay multiplication in the adjustable delay line to obtain reference signals; the second filtering and amplifying submodule is used for filtering and amplifying the optical signal passing through the adjustable delay line;

the second optical switch is used for receiving the reference signal and inputting the reference signal to the receiving and mixing module.

The adjustable delay line is a shunt type delay line structure, and the optical signal is controlled by the second optical coupler to select different paths so as to select different delay amounts.

More preferably, the optical fiber delay line comprises a plurality of reference signal delay modules, wherein the plurality of reference signal delay modules are sequentially connected in series and used for sequentially delaying the passing optical signals, and the delay intervals of the plurality of reference signal delay modules can be independently set;

the second optical switch is only arranged at the output end of the last reference signal delay module and is used for outputting the reference signal to the receiving mixing module.

More preferably, the optical fiber coupler comprises two reference signal delay modules arranged in parallel, wherein the two reference signal delay modules are used for respectively receiving the same optical signal, realizing delay multiplication and respectively outputting the reference signal to the receiving frequency mixing module; the delay intervals of the two reference signal delay blocks can be set independently.

Specifically, the receiving and frequency mixing module comprises a second photoelectric converter, a second filtering and amplifying submodule, a frequency mixer, a low-noise amplifying and filtering submodule and a receiving antenna;

the second photoelectric converter is used for receiving the reference signal and converting the reference signal into a reference electric signal;

the second filtering and amplifying submodule is used for receiving the reference electric signal and carrying out filtering and amplifying processing;

the receiving antenna is used for receiving the returned radio frequency antenna signal to obtain an echo signal;

the low-noise amplification filtering submodule is used for receiving the echo signal and performing low-noise amplification and filtering processing;

the frequency mixer is used for respectively receiving the echo signal and the reference electric signal to carry out deskew frequency mixing processing to obtain a dot frequency signal.

Specifically, the receiving and mixing module comprises a second electro-optical modulator, a third photoelectric converter, a low-noise amplification filtering submodule and a receiving antenna;

the receiving antenna is used for receiving the returned radio frequency antenna signal to obtain an echo signal;

the low-noise amplification filtering submodule is used for receiving the echo signal and performing low-noise amplification and filtering processing;

the second electro-optical modulator is used for respectively receiving the processed echo signal and the reference signal and converting the echo signal into an optical signal;

the third photoelectric converter is linked with the optical path of the second electro-optical modulator, the echo signal and the reference signal realize deskew frequency mixing on the optical link between the third photoelectric converter and the second electro-optical modulator to obtain a dot frequency signal, and the third photoelectric converter is used for receiving the dot frequency signal, converting the dot frequency signal into a dot frequency signal of an electric signal and outputting the dot frequency signal to the analysis processing module.

Specifically, the analysis processing module comprises a third filtering and amplifying sub-module and a digital acquisition and signal processing unit;

the third filtering and amplifying submodule is used for receiving the corresponding dot frequency signal and carrying out filtering and amplifying processing;

and the signal processing unit is used for receiving the spot frequency signals after filtering and amplifying processing, processing and analyzing the spot frequency signals and obtaining the processing information of the microwave photon radar.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following advantages and positive effects:

the invention utilizes the light signal to circulate for many times, automatically realizes the multiple delay without intervals and repetition, and the delay can adopt the optical switch to switch different delay amounts participating in the circulation, thereby controlling the length of the optical fiber ring, setting the cycle period and replacing the function of the optical switch. On the basis of the adjustable controllable optical delay line, the microwave photon radar can realize non-blind area and non-repeated detection and mapping in the maximum range.

The structure is simple, the core delay structure is established on the basis of the optical automatic increasing cyclic delay, and a multi-stage multipath delay line is not needed.

The structure has good expansibility, and the series connection and combination of the delay structures can be implemented according to the requirements, so that different delay requirements are met.

The expansibility of the structure is also shown in that the structure is suitable for being applied to a two-dimensional phased array radar under the condition of parallel connection.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention.

FIG. 1 is a diagram of a microwave photonic radar according to a first embodiment of the present invention;

FIG. 2 is a diagram of a microwave photonic radar according to a second embodiment of the present invention;

FIG. 3 is a diagram of a microwave photonic radar according to a third embodiment of the present invention;

fig. 4 is a structural view of a microwave photonic radar according to a fourth embodiment of the present invention.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description will be made with reference to the accompanying drawings. It is obvious that the drawings in the following description are only some examples of the invention, and that for a person skilled in the art, other drawings and embodiments can be derived from them without inventive effort.

For the sake of simplicity, only the parts relevant to the present invention are schematically shown in the drawings, and they do not represent the actual structure as a product. In addition, in order to make the drawings concise and understandable, components having the same structure or function in some of the drawings are only schematically illustrated or only labeled. In this document, "one" means not only "only one" but also a case of "more than one".

The microwave photonic radar provided by the invention is further described in detail by combining the figures and the specific embodiments. Advantages and features of the present invention will become apparent from the following description and from the claims.

Example 1

Referring to fig. 1, the present embodiment provides a microwave photonic radar including a radar signal generation module, a radar signal transmission module, a reference signal delay module, a receiving and mixing module, and an analysis processing module.

And the radar signal generation module is respectively connected with the radar signal emission module and the reference signal delay module through light paths and is used for generating a narrow-band radar signal, converting the narrow-band radar signal into two paths of optical signals and outputting the two paths of optical signals. Specifically, the radar signal generation module includes a radar signal generator, a first electro-optical modulator, a laser source, and a first optical coupler. The radar signal generator is in signal connection with the first electro-optical modulator and outputs a narrow-band radar signal to the first electro-optical modulator. The laser source provides a light source for the first electro-optical modulator, the first electro-optical modulator is matched with the light source to carry out frequency doubling processing on the passing narrow-band radar signal, and the narrow-band radar signal is converted into an optical signal from an electric signal. The narrow-band radar signal converted into the optical signal is sent to the first optical coupler, and the first optical coupler divides the received optical signal into two parts which are respectively input to the radar signal transmitting module and the reference signal delay module.

Specifically, the laser light source is a multi-wavelength output light source or a multi-frequency output laser light source, and the multi-wavelength output light source or the multi-frequency output laser light source is collected into a light path through a wavelength division multiplexer, and a wavelength division demultiplexer and a light reflecting mirror are designed in the optical cycle delay structure, so that the multi-wavelength laser signals can be continuously delayed in the subsequent same optical cycle structure light path.

The optical signal is output by two paths, one path of the optical signal enters the radar signal transmitting module, is converted into a microwave signal through photoelectric conversion, is subjected to microwave filtering and amplification, and is transmitted through the transmitting antenna. Specifically, the radar signal transmitting module comprises a first photoelectric converter, a first filtering and amplifying submodule, a microwave power amplifier and a radio frequency transmitting antenna; the optical signal enters a first photoelectric converter to realize photoelectric conversion, a microwave signal is obtained, then the microwave signal enters a first filtering and amplifying submodule to be filtered and amplified, then the microwave signal is amplified through a microwave power amplifier, finally the microwave signal enters a radio frequency transmitting antenna, and the microwave signal is converted into a radio frequency antenna signal to be transmitted.

And the other path of the optical signal enters a reference signal delay module in the form of an optical signal, and enters a receiving and mixing module after being output. Specifically, the reference signal delay module comprises a first optical switch, a second optical coupler, a second filtering and amplifying submodule and an adjustable delay line. In the implementation process, the second optical switch is closed, the first optical switch is opened, so that the optical signal is guided into the second optical coupler through the first optical switch, and then the first optical switch is closed, so that the optical signal is circulated for many times in an annular optical path formed by the coupler and the adjustable delay line, and the delay multiplication of the radar signal is realized.

In this embodiment, a tunable delay line is designed, the optical delay line is a branch-type delay line structure, the delay amount can be selected, once the selection is determined, the delay amount can be kept unchanged in the optical circulation loop, different paths can be controlled and selected according to the delay requirement, and the optical signal can enter the path to be entered through the second optical coupler.

The second filtering amplification submodule is arranged on a transmission path of an optical path of the adjustable delay line, compensates loss caused by circular coupling of optical signals, and amplifies different optical signal powers caused by coupling output, so that the module can form uninterrupted delay amount and ultra-large delay amount.

And after the optical signal reaches a required value through delay processing of the adjustable delay line, the required reference signal is obtained, the second optical switch is switched on, and the reference signal is input to the receiving frequency mixing module. Therefore, the first optical switch, the second optical switch and the second optical coupler can work coordinately and coordinately, and work cooperatively according to a certain time sequence according to needs, so as to complete expected delay output. The first optical coupler and the second optical coupler are optical fiber couplers or optical waveguide couplers or photonic integrated chip-based couplers, and are 2 × 2 optical couplers.

Next, in this embodiment, the receiving and mixing module is in signal connection with the reference signal delay module, and is configured to perform deskew mixing and receiving on the radio frequency radar echoes corresponding to the reference signal and the radio frequency antenna signal, respectively, to obtain a dot frequency signal. Specifically, the receiving and mixing module comprises a second photoelectric converter, a second filtering and amplifying submodule, a mixer, a low-noise amplifying and filtering submodule and a receiving antenna. The reference signal of the optical signal enters the second photoelectric converter to be converted into a reference electric signal, namely a microwave signal, and then enters the second filtering and amplifying submodule to carry out filtering and amplifying processing, so that the output power difference of each sequence is reduced. The receiving antenna receives the returned radio frequency antenna signal to obtain an echo signal, and the echo signal enters the low-noise amplifier filtering submodule to carry out low-noise amplification and filtering processing. Then, the echo signal and the reference electric signal enter a mixer to be processed by deskew mixing, so as to obtain a dot frequency signal, namely a frequency difference signal.

Wherein, the mixer is a broadband or ultra-wideband mixer.

The analysis processing module is used for receiving the dot frequency signals to carry out processing analysis so as to obtain processing information of the microwave photon radar. Specifically, the analysis processing module comprises a third filtering and amplifying submodule and a digital acquisition and signal processing unit. The dot frequency signal enters a third filtering and amplifying submodule for filtering and amplifying, and then enters a signal processing unit for processing and displaying radar detection by using software to obtain processing information related to the embodiment. This embodiment belongs to chirp continuous wave radar, and then can carry out range finding, speed measuring, angle measurement and formation of image.

Example 2

Referring to fig. 2, the present embodiment provides another microwave photonic radar, which is different from embodiment 1 in that a reference signal and a received echo signal of the present embodiment are subjected to deskew mixing processing in an optical domain, and the remaining design is the same as embodiment 1, and is not described again.

Specifically, in this embodiment, the receiving and mixing module includes a second electro-optical modulator, a third electro-optical converter, a low-noise amplifier and filter sub-module, and a receiving antenna.

After the reference signal modulated with the broadband radar signal comes out of the second optical switch, photoelectric conversion is not performed, and the reference signal directly enters the optical input port of the second electro-optical modulator. And the receiving antenna receives the returned radio frequency antenna signal to obtain an echo signal, the echo signal is sent to the low-noise amplification and filtering submodule to be subjected to low-noise amplification and filtering processing, and the processed echo signal enters the electric input port of the second electro-optic modulator. The echo signal and the reference signal are processed by deskew mixing on the optical link, and then converted into dot frequency signals by the third photoelectric converter, and the subsequent processing is the same as that of embodiment 1.

In this embodiment, the second electro-optical modulator may be an intensity modulator, an electro-optical phase modulator, or an electro-optical polarization modulator.

Example 3

Referring to fig. 3, this example provides another embodiment of a microwave photonic radar, which has an internal structure including a plurality of reference signal delay modules connected in series, and the rest of the configuration is the same as that of example 1. Preferably, the optical signal pair sequentially passes through the reference signal delay module for delay, and the delay interval of each reference signal delay module can be independently set, that is, the delay amount and the delay interval of each pipeline in each annular structure are different. The delay time of the optical signal in the previous reference signal delay module is determined by controlling the optical switches of the reference signal delay modules between adjacent reference signal delay modules. When the optical signal arrives at the last reference signal delay module, the reference signal is sent to the receiving frequency mixing module through the second optical switch arranged at the output end of the reference signal delay module. According to the arrangement, more delay amounts and more fine delay intervals are obtained by the reference signal delay modules with different parameters and controlling the optical switches in the reference signal delay modules.

Example 4

Referring to fig. 4, the present embodiment provides another microwave photonic radar, which has an internal structure of two reference signal delay modules disposed in parallel. Because two reference signal delay modules are arranged, the optical signal output by the radar signal generation module is divided into three paths, wherein the two paths respectively enter the two reference signal delay modules. The device is used for receiving the same optical signals respectively, realizing delay multiplication and outputting reference signals to the receiving and mixing modules respectively, and parameters such as delay intervals of the two reference signal delay modules can be set and controlled independently. So as to form a larger delay amount and a finer delay interval.

Because there are reference signal delay modules arranged in parallel, the subsequent receiving and mixing modules and the analysis processing module are also arranged in a corresponding multiple. However, the devices and the implementation thereof are not obviously different from those in embodiment 1, and therefore, the description thereof is omitted.

Preferably, the parallel and series combined expansion can be performed by combining with the embodiment 3, so that not only more delay amount and finer delay interval are formed, but also the delay can be performed facing the two-dimensional phased array radar antenna.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, it is still within the scope of the present invention if they fall within the scope of the claims of the present invention and their equivalents.

Claims (10)

1. A microwave photonic radar, comprising:

the device comprises a radar signal generating module, a radar signal transmitting module, a reference signal delaying module, a receiving frequency mixing module and an analyzing and processing module;

the radar signal generation module is respectively connected with the radar signal emission module and the reference signal delay module through light paths and is used for generating a narrow-band radar signal, converting the narrow-band radar signal into two paths of optical signals and outputting the two paths of optical signals;

the radar signal transmitting module is used for receiving one path of optical signal and converting the optical signal into a radio frequency antenna signal to be transmitted;

the reference signal delay module is used for receiving another path of optical signal to perform delay processing to obtain a reference signal,

the receiving and frequency mixing module is in signal connection with the reference signal delay module and is used for respectively carrying out deskew frequency mixing receiving on the reference signal and the radio frequency radar echo corresponding to the radio frequency antenna signal to obtain a dot frequency signal;

the analysis processing module is used for receiving the dot frequency signal to perform processing analysis to obtain processing information of the microwave photon radar.

2. The microwave photonic radar of claim 1, wherein the radar signal generation module comprises a radar signal generator, a first electro-optical modulator, a laser source, and a first optical coupler;

the radar signal generator is in signal connection with the first electro-optical modulator and is used for outputting the narrow-band radar signal to the first electro-optical modulator;

the laser source provides a light source for the first electro-optical modulator;

the first electro-optical modulator is used for receiving the narrow-band radar signal and converting the narrow-band radar signal into an optical signal by matching with the laser source and then outputting the optical signal;

the first optical coupler is used for receiving a light signal and then dividing the light signal into two parts which are respectively input to the radar signal transmitting module and the reference signal delay module.

3. The microwave photonic radar of claim 1, wherein the radar signal transmitting module comprises a first photoelectric converter, a first filtering and amplifying sub-module, a microwave power amplifier, and a radio frequency transmitting antenna;

the first photoelectric converter is used for receiving optical signals and converting the optical signals;

the first filtering and amplifying submodule is used for receiving the electric signal and carrying out filtering and amplifying processing;

the microwave power amplifier is used for receiving the filtered and amplified electric signal and amplifying the power;

and the radio frequency transmitting antenna is used for converting the electric signal after receiving power amplification into the radio frequency antenna signal to be transmitted.

4. The microwave photonic radar of claim 1,

the reference signal delay module comprises a first optical switch, a second optical coupler, a second filtering and amplifying submodule and an adjustable delay line;

the first optical switch is used for receiving another optical signal from the radar signal generation module and guiding the other optical signal into the second optical coupler;

the second optical coupler and the second filtering and amplifying submodule are arranged on a light path conducting path of the adjustable delay line, the second optical coupler is used for receiving optical signals and is matched with the first optical switch and the second optical switch to enable the optical signals to realize delay multiplication in the adjustable delay line so as to obtain the reference signal; the second filtering and amplifying submodule is used for carrying out filtering and amplifying processing on the optical signal passing through the adjustable delay line;

the second optical switch is used for receiving the reference signal and inputting the reference signal to the receiving and mixing module.

5. The microwave photonic radar of claim 4, wherein the adjustable delay line is a split-type delay line structure, and the optical signal is controlled by the second optical coupler to select different paths to select different delay amounts.

6. The microwave photonic radar as claimed in claim 5, comprising a plurality of the reference signal delay modules, wherein the reference signal delay modules are sequentially arranged in series for sequentially delaying the passing optical signal, and the delay intervals of the reference signal delay modules can be independently set;

the second optical switch is only arranged at the output end of the last reference signal delay module and is used for outputting the reference signal to the receiving mixing module.

7. The microwave photonic radar as claimed in claim 5, comprising two reference signal delay modules arranged in parallel, wherein the two reference signal delay modules are configured to respectively receive the same optical signal and realize delay multiplication, and respectively output the reference signal to the receiving mixing module; the delay intervals of the two reference signal delay modules can be set independently.

8. The microwave photonic radar of any one of claims 1, 6 or 7, wherein the receive mixing module comprises a second photoelectric converter, a second filtering amplification sub-module, a mixer, a low-noise amplification filtering sub-module, and a receive antenna;

the second photoelectric converter is used for receiving the reference signal and converting the reference signal into a reference electric signal;

the second filtering and amplifying submodule is used for receiving the reference electric signal and carrying out filtering and amplifying processing;

the receiving antenna is used for receiving the returned radio frequency antenna signal to obtain an echo signal;

the low-noise amplifier filtering submodule is used for receiving the echo signal and carrying out low-noise amplification and filtering processing;

and the frequency mixer is used for respectively receiving the echo signal and the reference electric signal to carry out deskew frequency mixing processing to obtain the dot frequency signal.

9. The microwave photonic radar of any one of claims 1, 6 or 7, wherein the receive mixing module comprises a second electro-optical modulator, a third electro-optical converter, a low-noise amplifier filter sub-module, and a receive antenna;

the receiving antenna is used for receiving the returned radio frequency antenna signal to obtain an echo signal;

the low-noise amplifier filtering submodule is used for receiving the echo signal and carrying out low-noise amplification and filtering processing;

the second electro-optical modulator is used for respectively receiving the processed echo signal and the reference signal and converting the echo signal into an optical signal;

the third photoelectric converter is linked with the optical path of the second electro-optical modulator, the echo signal and the reference signal realize deskew frequency mixing on the optical link between the third photoelectric converter and the second electro-optical modulator to obtain the dot frequency signal, and the third photoelectric converter is used for receiving the dot frequency signal, converting the dot frequency signal into an electrical signal, and outputting the electrical signal to the analysis processing module.

10. The microwave photonic radar of claim 1, wherein the analysis processing module comprises a third filtering and amplification sub-module and a digital sampling and signal processing unit;

the third filtering and amplifying submodule is used for receiving the corresponding dot frequency signal and carrying out filtering and amplifying processing;

and the signal processing unit is used for receiving the spot frequency signals after filtering and amplifying processing, processing and analyzing the spot frequency signals, and obtaining the processing information of the microwave photon radar.

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