CN116299243A

CN116299243A - X-band Doppler radar target simulator and X-band Doppler radar sensing test system

Info

Publication number: CN116299243A
Application number: CN202310418436.1A
Authority: CN
Inventors: 林水洋; 何德宽; 俞建海; 黄灵军
Original assignee: Gekong Shanghai Intelligent Technology Co ltd
Current assignee: Gekong Shanghai Intelligent Technology Co ltd
Priority date: 2023-04-18
Filing date: 2023-04-18
Publication date: 2023-06-23

Abstract

The invention provides an X-band Doppler radar target simulator and an X-band Doppler radar sensing test system, which are characterized in that according to the Doppler radar principle, an echo signal containing detection target information is generated and returned to an X-band electromagnetic wave radar after an X-band electromagnetic wave signal is received by a circuit of the X-band Doppler radar target simulator, so that the speed information and the amplitude information of the radar echo signal are accurately set by a given amount, adjustable and repeatable target signal which is difficult to quantify, inflexible and poor in repeatability in the prior art; in addition, the invention realizes the conversion of the X-band electromagnetic wave signal to the C-band or S-band for subsequent signal processing by arranging the frequency division module and the frequency multiplication module which adopt the same multiple, so that not only can the C-band or S-band element be used for processing the intermediate radio frequency signal, but also a high-speed digital-to-analog converter is not required to be used for generating the intermediate frequency signal, thereby reducing the development difficulty and the development cost.

Description

X-band Doppler radar target simulator and X-band Doppler radar sensing test system

Technical Field

The invention relates to the field of X-band Doppler radar, in particular to an X-band Doppler radar target simulator and an X-band Doppler radar sensing test system.

Background

With the gradual deepening of radar technology from military to civil use, microwave radar is used as a sensor and applied to various consumer products. The microwave radar sensor can be installed in a hidden mode, is not influenced by temperature, air flow, dust, smoke and the like, has the advantages of long service life, high reaction speed, higher sensitivity, wide induction area and the like, gradually replaces the sensing technologies such as infrared, sound control and the like to be widely applied to consumer electronic products in multiple fields, comprises energy-saving illumination, security protection, intelligent household appliances and the like, and is an important link in the research and development of the microwave radar products and the production process of the microwave radar products.

Compared with C-band or S-band radars, the civil X-band Doppler radar has the advantages that the frequency is relatively higher, the wavelength is shorter, the size of the same type of antenna is relatively smaller, the size of the module is relatively smaller, the space required by installation layout in a used product is smaller, and meanwhile, the frequency of the X-band radar avoids the interference of 5G signals, so that the application of small and medium intelligent household appliances at home and abroad is more and more popular. For the current X-band radar, an angular antenna, a wobbler, a person walking or waving, etc. are generally used as detection targets for testing the X-band radar sensor, but this approach has drawbacks in that: the test results are perceptively difficult to quantify, inflexible and poorly reproducible. Especially in the production test, when a plurality of X-band radar sensor products are detected and tested with targets at the same time, the scheme can amplify the deviation of the sensing results of different X-band radar sensors, so that the consistency is deteriorated, and the real performance of the X-band radar products cannot be truly tested.

And, the radar of X wave band is shorter in wavelength, and the requirement on the PCB material and the impedance control of target simulator is higher for the radar of C wave band and S wave band, and can only adopt X wave band radio frequency element, and can not use C wave band or S wave band element to handle intermediate radio frequency signal, makes the cost higher. And the Doppler frequency corresponding to the same target speed is higher than the C-band or S-band because the radio frequency of the X-band is higher, namely the frequency of the intermediate frequency signal which needs to be simulated by the digital-to-analog converter is proportionally increased, so that the intermediate frequency signal is generated by using the high-speed digital-to-analog converter, and the development difficulty and the development cost are increased.

Disclosure of Invention

In view of the above drawbacks of the prior art, an object of the present invention is to provide an X-band doppler radar target simulator and an X-band doppler radar sensing test system, which are used for solving the above technical problems in the prior art.

To achieve the above and other related objects, the present invention provides an X-band doppler radar target simulator for simulating a target speed and a target amplitude of a detection target, the target simulator comprising: the device comprises an X-band signal receiving module, a low-noise amplifier, a frequency dividing module, a first attenuation module, a signal conversion and phase shift module, a first mixer, a second mixer, a processing module, a digital-to-analog conversion module, a combiner, a frequency multiplication module, a second attenuator and a signal transmitting module; the X-band signal receiving module, the low-noise amplifier, the frequency dividing module, the first attenuator and the signal conversion and phase shift module are sequentially connected in series; the first mixer and the second mixer are respectively connected with the signal conversion and phase shift module, the digital-to-analog conversion module and the combiner; the processing module is connected with the digital-to-analog conversion module; the combiner, the frequency multiplication module, the second attenuator and the signal transmitting module are sequentially connected in series; the frequency division module and the frequency multiplication module adopt the same multiple and are used for converting the X-band electromagnetic wave signal into a C-band or S-band for subsequent signal processing and converting the processed C-band or S-band signal into an X-band; the signal receiving module receives an X-band electromagnetic wave signal sent by the X-band Doppler radar sensor, the low-noise amplifier amplifies the X-band electromagnetic wave signal, the frequency division module is used for down-converting the radio frequency of the signal to a radio frequency band of a circuit work between the frequency division module and the frequency multiplication module, and the first attenuator is used for adjusting the electromagnetic wave amplitude of the radio frequency electromagnetic wave signal after the frequency division; the signal conversion and phase shift module converts the regulated signal from a single-ended signal to a differential signal and outputs a pair of orthogonal radio frequency signals; converting, by the digital-to-analog conversion module, a pair of baseband analog quadrature signals that conform to the analog target characteristics according to the digital signals that conform to the analog target characteristics generated by the processing module based on the analog target parameters related to the detection target; the first mixer and the second mixer respectively mix the baseband analog quadrature signal with the radio frequency signal output by the signal conversion and phase shift module, and then add the signals mixed by the first mixer and the second mixer through the combiner; and the added signals are subjected to frequency multiplication processing through the frequency multiplication module, then subjected to signal amplitude adjustment through the second attenuator, and returned to the X-band Doppler radar sensor through the signal transmitting module according with the target speed and the target amplitude of the detected target.

In an embodiment of the present invention, the method for simulating the target speed of the detected target includes: the digital-to-analog conversion module changes parameters of the digital-to-analog conversion module according to digital signals generated by the processing module based on analog target parameters related to the target speed of a detection target, the digital-to-analog conversion module converts the digital-to-analog conversion module into baseband analog quadrature signal pairs conforming to the target frequency or the target phase, the baseband analog quadrature signal pairs are mixed with radio frequency signals output by the signal conversion and phase shift module through the first mixer and the second mixer respectively, and the mixed signals of the first mixer and the second mixer are added through the combiner, so that the added signals are subjected to frequency multiplication processing through the frequency multiplication module and the second attenuator in sequence, and the signal amplitude is adjusted to generate analog target signals conforming to the target speed; wherein a frequency offset between the analog target signal and the input X-band electromagnetic wave signal is changed by setting an analog target parameter to simulate a target speed corresponding to the frequency offset.

In an embodiment of the present invention, the method for simulating the target amplitude of the detection target includes: and adjusting the amplitude of the signal by setting one or more of parameters of a low noise amplifier, a frequency division module, a frequency multiplication module, a first attenuator, a second attenuator and a digital-to-analog conversion module, so as to generate an analog target signal of the output power which accords with the target amplitude.

In an embodiment of the present invention, the signal receiving module includes: a circular polarization receiving antenna, a first radio frequency switch and a receiving radio frequency head are arranged in the antenna; the built-in circularly polarized receiving antenna is used for receiving electromagnetic wave signals in the orthogonal direction; the receiving radio frequency head is used for externally connecting a receiving antenna so as to receive electromagnetic wave signals through the receiving antenna; the radio frequency switch is connected with the built-in circularly polarized receiving antenna and the receiving radio frequency head and is used for controlling the receiving antenna externally connected with the built-in circularly polarized receiving antenna or the receiving radio frequency head to receive electromagnetic wave signals so as to input the electromagnetic wave signals to the low noise amplifier.

In an embodiment of the present invention, the signal transmitting module includes: a circular polarization transmitting antenna, a second radio frequency switch and a transmitting radio frequency head are arranged in the antenna; the built-in circularly polarized transmitting antenna is used for transmitting the simulation target signal in a circularly polarized electromagnetic wave mode; the transmitting radio frequency head is used for being externally connected with a transmitting antenna so as to transmit the analog target signal through the transmitting antenna; the radio frequency switch is connected with the built-in circular polarization transmitting antenna and the transmitting radio frequency head and is used for controlling the transmitting antenna externally connected with the built-in circular polarization transmitting antenna or the transmitting radio frequency head to transmit the simulation target signal.

In an embodiment of the present invention, the built-in circular polarization receiving antenna and the built-in circular polarization transmitting antenna are respectively embedded in the front surface of a simulator circuit board of the X-band doppler radar target simulator, and a feed network which is arranged in cooperation with the built-in circular polarization receiving antenna and the built-in circular polarization transmitting antenna is respectively arranged at the back surface of the simulator circuit board; the built-in circular polarization receiving antenna and the built-in circular polarization transmitting antenna are respectively provided with a first feeding point and a second feeding point, and the first feeding point and the second feeding point connect the antennas with the corresponding feeding network in a metal via way; the first feeding point and the second feeding point are equal in distance from the geometric center of the corresponding antenna, and connecting lines of the two feeding points to the geometric center are orthogonal to each other; the built-in circularly polarized receiving antenna is combined with a corresponding feed network to receive an X-band electromagnetic wave signal sent by an X-band Doppler radar sensor; the built-in circularly polarized transmitting antenna is combined with a corresponding feed network to send the generated simulated target signal to a corresponding X-band Doppler radar sensor in a circularly polarized electromagnetic wave mode.

In an embodiment of the present invention, the signal conversion and phase shift module includes: balun for converting the regulated signal from a single-ended signal to a differential signal; and the phase shifter is connected with the balun and used for shifting the phase of the converted differential signal and outputting a pair of orthogonal radio frequency signals.

In an embodiment of the present invention, the processing module is configured to set the simulation target parameter based on a control instruction of a control end of an upper computer connected to the X-band radar target simulator, and generate a digital signal according with a characteristic of the simulation target.

In an embodiment of the present invention, the frequency dividing module is a frequency divider, and the frequency doubling module is a frequency multiplier; the frequency divider and the frequency multiplier adopt the same multiple.

To achieve the above and other related objects, the present invention provides an X-band doppler radar sensing test system, comprising: one or more X-band Doppler radar sensors are respectively arranged on the tool plane of the fixed tool; the X-band Doppler radar target simulator is arranged in the normal direction along the tool plane; the X-band Doppler radar target simulator simulates the target speed and the target amplitude of the detected target based on the received X-band electromagnetic wave signals transmitted by the X-band Doppler radar sensors and the simulated target parameters related to the detected target, and returns the simulated target signals conforming to the target speed and the target amplitude of the detected target to the corresponding X-band Doppler radar sensors so that the X-band Doppler radar sensors can acquire the target speed and the target amplitude of the detected target based on the received simulated target signals.

As described above, the invention is an X-band Doppler radar target simulator and an X-band Doppler radar sensing test system, which have the following beneficial effects: according to the Doppler radar principle, after an X-band electromagnetic wave signal is received, an echo signal containing detection target information is generated and returned to the X-band electromagnetic wave radar through a circuit of an X-band Doppler radar target simulator, and the speed information and the amplitude information of the radar echo signal are accurately set by a given amount, adjustable and repeatable target signals which are difficult to quantify, inflexible and poor in repeatability in the prior art; in addition, the invention realizes the conversion of the X-band electromagnetic wave signal to the C-band or S-band for subsequent signal processing by arranging the frequency division module and the frequency multiplication module which adopt the same multiple, so that not only can the C-band or S-band element be used for processing the intermediate radio frequency signal, but also a high-speed digital-to-analog converter is not required to be used for generating the intermediate frequency signal, thereby reducing the development difficulty and the development cost.

Drawings

Fig. 1 is a schematic diagram of an X-band doppler radar target simulator according to an embodiment of the invention.

Fig. 2 is a schematic structural diagram of an X-band doppler radar target simulator according to an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of an antenna plane and a feed network plane according to an embodiment of the invention.

Fig. 4 is a schematic diagram showing a trace length relationship of a feeding network according to an embodiment of the present invention.

Fig. 5 is a schematic structural diagram of an X-band doppler radar target simulator according to an embodiment of the present invention.

Fig. 6 is a schematic diagram showing an axial ratio index of an X-band doppler radar target simulator at each principal direction angle according to an embodiment of the present invention.

Fig. 7 is a schematic view of an application test environment of an X-band doppler radar sensing test system according to an embodiment of the invention.

Fig. 8 is a schematic diagram showing the installation of an X-band doppler radar sensor according to an embodiment of the present invention.

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention. It should be noted that the following embodiments and features in the embodiments may be combined with each other without conflict.

In the following description, reference is made to the accompanying drawings, which illustrate several embodiments of the invention. It is to be understood that other embodiments may be utilized and that mechanical, structural, electrical, and operational changes may be made without departing from the spirit and scope of the present invention. The following detailed description is not to be taken in a limiting sense, and the scope of embodiments of the present invention is defined only by the claims of the issued patent. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Spatially relative terms, such as "upper," "lower," "left," "right," "lower," "below," "lower," "above," "upper," and the like, may be used herein to facilitate a description of one element or feature as illustrated in the figures relative to another element or feature.

Throughout the specification, when a portion is said to be "connected" to another portion, this includes not only the case of "direct connection" but also the case of "indirect connection" with other elements interposed therebetween. In addition, when a certain component is said to be "included" in a certain section, unless otherwise stated, other components are not excluded, but it is meant that other components may be included.

The first, second, and third terms are used herein to describe various portions, components, regions, layers and/or sections, but are not limited thereto. These terms are only used to distinguish one portion, component, region, layer or section from another portion, component, region, layer or section. Thus, a first portion, component, region, layer or section discussed below could be termed a second portion, component, region, layer or section without departing from the scope of the present invention.

Furthermore, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes," and/or "including" specify the presence of stated features, operations, elements, components, items, categories, and/or groups, but do not preclude the presence, presence or addition of one or more other features, operations, elements, components, items, categories, and/or groups. The terms "or" and/or "as used herein are to be construed as inclusive, or meaning any one or any combination. Thus, "A, B or C" or "A, B and/or C" means "any of the following: a, A is as follows; b, a step of preparing a composite material; c, performing operation; a and B; a and C; b and C; A. b and C). An exception to this definition will occur only when a combination of elements, functions or operations are in some way inherently mutually exclusive.

The invention provides an X-band Doppler radar target simulator and an X-band Doppler radar sensing test system, which are characterized in that according to the Doppler radar principle, an echo signal containing detection target information is generated and returned to an X-band electromagnetic wave radar after an X-band electromagnetic wave signal is received by a circuit of the X-band Doppler radar target simulator, so that the speed information and the amplitude information of the radar echo signal are accurately set by a given amount, adjustable and repeatable target signal which is difficult to quantify, inflexible and poor in repeatability in the prior art; in addition, the frequency division module and the frequency multiplication module which are the same in multiple are adopted to convert the X-band electromagnetic wave signal into the C-band or the S-band for subsequent signal processing, so that the C-band or the S-band element can be used for processing the intermediate radio frequency signal, and a high-speed digital-to-analog converter is not required to be used for generating the intermediate frequency signal, and further the development difficulty and the development cost are reduced.

The embodiments of the present invention will be described in detail below with reference to the attached drawings so that those skilled in the art to which the present invention pertains can easily implement the present invention. This invention may be embodied in many different forms and is not limited to the embodiments described herein.

Fig. 1 shows a schematic structural diagram of an X-band doppler radar target simulator in an embodiment of the present invention.

The X-band Doppler radar target simulator is used for simulating the target speed and the target amplitude of the detected target.

The X-band Doppler radar target simulator comprises: the X-band signal receiving module 1, the low noise amplifier 2, the frequency dividing module 3, the first attenuator 4, the signal converting and phase shifting module 5, the first mixer 6, the second mixer 7, the processing module 8, the digital-to-analog conversion module 9, the combiner 10, the frequency doubling module 11, the second attenuator 12 and the signal transmitting module 13 are integrated on the circuit board of the simulator.

The X-band signal receiving module 1, the low-noise amplifier 2, the frequency dividing module 3, the first attenuator 4 and the signal conversion and phase shift module 5 are sequentially connected in series; specifically, the signal receiving module 1 is connected with the low noise amplifier 2, the low noise amplifier 2 is connected with the frequency dividing module 3, the frequency dividing module 3 is connected with the first attenuator 4, and the first attenuator 4 is connected with the signal conversion and phase shift module 5.

The first mixer 6 and the second mixer 7 are connected in parallel and are respectively connected with the signal conversion and phase shift module 5, the digital-to-analog conversion module 9 and the combiner 10; the processing module 8 is connected with the digital-to-analog conversion module 9; the combiner 10, the frequency doubling module 11, the second attenuator 12 and the signal transmitting module 13 are sequentially connected in series; specifically, the combiner 10 is connected to a frequency multiplication module 11, the frequency multiplication module 11 is connected to the second attenuator 12, and the second attenuator 12 is connected to the signal transmitting module 13.

The frequency division module 3 and the frequency multiplication module 11 adopt the same multiple, and are used for converting an X-band electromagnetic wave signal into a C-band or an S-band for subsequent signal processing, and converting the processed C-band or S-band signal into an X-band.

The signal receiving module 1 receives an X-band electromagnetic wave signal sent by the X-band Doppler radar sensor, the low-noise amplifier 2 amplifies the X-band electromagnetic wave signal, the frequency division module 3 down-converts the signal radio frequency to a radio frequency band of circuit operation between the frequency division module 3 and the frequency multiplication module 11, and the first attenuator 4 adjusts the signal amplitude of the frequency-divided radio frequency electromagnetic wave signal;

the signal conversion and phase shift module 5 converts the regulated signal from a single-ended signal to a differential signal, outputs a pair of orthogonal radio frequency signals, and transmits the signals to the first mixer 6 and the second mixer 7; meanwhile, the processing module 8 generates a digital signal according with the analog target characteristic based on the analog target parameter related to the detection target, and converts the digital signal according with the analog target characteristic into a pair of baseband analog orthogonal signals according with the analog target characteristic through the digital-to-analog conversion module 9; the first mixer 6 and the second mixer 7 respectively mix the baseband analog quadrature signal with the radio frequency signal output by the signal conversion and phase shift module 5, and then add the signals mixed by the first mixer 6 and the second mixer 7 through the combiner 10; the added signals are subjected to frequency multiplication processing by the frequency multiplication module 11, the down-conversion signals loaded with simulator target information are subjected to frequency multiplication processing by the frequency multiplication module, then the signals are subjected to signal amplitude adjustment by the second attenuator 12, and the simulation target signals which accord with the target speed and the target amplitude of the detection target are returned to the X-band Doppler radar sensor by the signal transmission module 13.

The processing module 8 can be a microprocessor MCU, and can also use schemes such as FPGA, and the scheme does not need to use a very high-end microprocessor, so that the software development difficulty and cost are reduced.

Based on the use of the frequency division module 3 and the frequency multiplication module 11, the X wave band is converted into a more common C wave band or S wave band for signal processing, so that the requirements on PCB materials and impedance control are reduced, and the gain loss caused by PCB microstrip routing is reduced; meanwhile, the use of the X-band radio frequency element can be reduced, the C-band or S-band element is used for processing the intermediate radio frequency signal, and the C-band or S-band element is relatively more common and has lower cost; in addition, the Doppler frequency corresponding to the same target speed is higher than the C-band or S-band due to the higher radio frequency of the X-band, namely the frequency of the intermediate frequency signal to be simulated by the digital-to-analog converter is proportionally increased, so that a high-speed digital-to-analog converter is required to generate the intermediate frequency signal, and the development difficulty and cost are increased; the invention reduces the pressure of the digital-to-analog converter which needs to output the intermediate frequency signal with very high frequency by using the frequency division module and the frequency multiplication module, does not need to use a high-speed digital-to-analog converter any more, and reduces the development difficulty and the cost.

Preferably, the PCB size of the simulator circuit board is only 100 x 60mm, the space requirement on the use environment is low, and the high-integration and miniaturization design is realized.

In order to better describe the specific manner in which an X-band doppler radar target simulator simulates a detection target, the following specific embodiments will be described.

In one embodiment, the method for simulating the target speed of the detected target includes:

changing parameters of the digital-to-analog conversion module 9 by the digital-to-analog conversion module 9 according to digital signals which are received from the processing module and are generated based on analog target parameters related to the target speed of a detection target, converting the digital-to-analog conversion module 9 into baseband analog quadrature signal pairs conforming to the target frequency or the target phase, respectively mixing the baseband analog quadrature signal pairs with radio frequency signals output by the signal conversion and phase shift module 5 by the first mixer 6 and the second mixer 7, and adding the signals mixed by the first mixer 6 and the second mixer 7 by the combiner 10 so as to enable the signals added by the signals to be subjected to frequency multiplication processing and signal amplitude adjustment by the frequency multiplication module 11 and the second attenuator 12 in sequence to generate analog target signals conforming to the target speed;

Wherein a frequency offset between the analog target signal and the input X-band electromagnetic wave signal is changed by setting an analog target parameter to simulate a target speed corresponding to the frequency offset.

Namely, in this embodiment, the parameters of the digital-to-analog conversion module 9 are changed to convert the baseband analog orthogonal signal pair according with the target frequency, so as to obtain an analog target signal according with the detected target speed, so that the X-band radar sensor can obtain the corresponding target speed.

Further, the principle of simulating the detected target speed of the detected target is as follows:

the radio frequency emitted by the Doppler radar sensor in the X wave band is f ₀ Wavelength lambda ₀ ＝c/f ₀ C is the propagation speed of electromagnetic wave in vacuum, the distance between the target and the radar is R, and the total wavelength number of the radar sending signal to the target and then returning the signal from the target to the radar is 2R/lambda ₀ I.e. the total phase

When the target moves, the moving target speed is v _t The phase phi changes along with the distance R to generate Doppler effect, and the corresponding Doppler frequency is f _d Angular velocity omega _d ＝2π·f _d At the same time

Then

The simulation method for realizing the target speed of the X-band Doppler radar is introduced below.

The X-band Doppler radar target simulator receives the sine wave RF signal from radar _in Can be simply defined as cos (omega) _r t), the signal is after passing through the low noise amplifier 2, the frequency dividing module 3 (the frequency dividing module frequency dividing multiple is N) and the first attenuator 4 without considering the phase shift and delay of the air transmission

Then the two paths of orthogonal signals are obtained as +.>

And->

Respectively into the first mixer 6 and the second mixer 7. The intermediate frequency signal 1 and the intermediate frequency signal 2 sent by the digital-to-analog conversion module 9 are baseband quadrature signals with the same frequency and amplitude and 90 degrees phase difference, wherein the intermediate frequency signal 1 can be simply defined as cos (omega) _i t), the intermediate frequency signal 2 can be simply defined as sin (ω) _i t)。

The mixed output signal of the first mixer 6 results in:

the mixed output signal of the second mixer 7 results in:

the output signal results of the first mixer 6 and the second mixer 7 are synthesized and added by the combiner 10 to obtain the output signal result as follows:

then passes through a frequency multiplication module 11 (the frequency multiplication multiple of the frequency multiplication module is N the same as the frequency division multiple of the frequency division module) and a second attenuator 12, and then RF _out The signal frequency is:

RF _out ＝cos((ω _r -Nω _i )t)； (6)

it follows that the input radar signal RF of the X-band Doppler radar target simulator _in Frequency omega _r Output signal RF of/2 pi _out Frequency is (omega) _r -Nω _i ) Output signal RF of X-band Doppler radar target simulator _out Compared with the input signal RF _in The frequency offset is (-N omega) _i )/2πThe frequency offset is negative, and the simulated scene is the Doppler shift frequency corresponding to the speed of the target when the target is far away from the radar. By setting and changing parameters of the digital-to-analog conversion module to generate intermediate frequency signals 1 and intermediate frequency signals 2 with different frequencies, target analog signals with different speeds can be simulated.

Therefore, the

intermediate frequency signals

1 and 2 with different frequencies can be generated by setting and changing the frequency parameters of the digital-to-analog conversion module 9, so that target analog signals with different speeds can be simulated.

Similarly, parameters sent to the digital-to-analog conversion module 9 by the processing module 8 can be modified by the control end of the upper computer to adjust the phase relationship between the intermediate frequency signal 1 and the intermediate frequency signal 2, and at this time, the intermediate frequency signal 1 can be simply defined as sin (ω) _i t), the intermediate frequency signal 2 can be defined simply as cos (ω) _i t)。

The mixed output signal of the first mixer 6 results in:

the mixed output signal of the second mixer 7 results in:

then passes through a frequency multiplication module 11 (the frequency multiplication multiple of the frequency multiplication module 11 is N the same as the frequency division multiple of the frequency divider) and a second attenuator 12, and then RF _out The signal frequency is:

RF _out ＝cos((ω _r +Nω _i )t)； (10)

at this time, the X-band Doppler radar target simulationInput radar signal RF of a receiver _in Frequency omega _r Output signal RF of/2 pi _out Frequency is (omega) _r +Nω _i ) Output signal RF of X-band Doppler radar target simulator _out Compared with the input signal RF _in The frequency offset is (+nω) _i ) And/2 pi, wherein the frequency offset is a positive value, and the simulated scene is Doppler frequency shift frequency corresponding to the speed when the target approaches the radar.

Therefore, by setting the intermediate frequency signal 1 and the intermediate frequency signal 2 with different phases by changing the phase parameters of the digital-to-analog conversion module 9, the target analog signals with different speeds can be simulated.

From the above, as shown in the formula (2), the doppler frequency corresponding to the same target speed is higher than the C-band or S-band due to the higher rf frequency of the X-band, that is, the frequency of the intermediate frequency signal to be simulated by the digital-to-analog conversion module is proportionally increased, so that a high-speed digital-to-analog converter is required to generate the intermediate frequency signal, thereby increasing the difficulty and cost of development. The target speed simulation deduction formulas (6) and (10) can know that after passing through the frequency multiplication module, the frequency of the intermediate frequency signal is multiplied, namely, the frequency of the intermediate frequency signal generated by the digital-to-analog converter is multiplied to be reduced at the same speed of the simulation target, so that the pressure of the intermediate frequency signal with very high frequency required to be output by the digital-to-analog converter is reduced, a high-speed digital-to-analog converter is not required, and the development difficulty and the development cost are reduced.

In one embodiment, RCS (radar cross-sectional area) is an imaginary area defined as the ratio of the reverse echo power to the incident injection power density of a radar detection target in a given direction, the parameter being described in terms of unit area. The larger the RCS value, the stronger the backscatter echo capability, and the greater the echo power received by the radar.

The manner of simulating the target amplitude RCS of the detection target includes:

the amplitude of the signal is adjusted by setting one or more modes of parameters of the low noise amplifier 2, the frequency division module 3, the frequency multiplication module 11, the first attenuator 4, the second attenuator 12 and the digital-to-analog conversion module 9, so that an analog target signal of the output power which accords with the target amplitude is generated.

The output power of the X-band doppler radar target simulator can be controlled by utilizing various combinations of parameters such as the adjustment of the low noise amplifier 2, the frequency dividing module 3, the frequency doubling module 11, the first attenuator 4, the second attenuator 12, the amplitude of an intermediate frequency signal sent by the digital-to-analog conversion module 9, and the like, so that the purpose of simulating the target amplitude is achieved, the purpose of simulating the detection target amplitude information (RCS) is achieved, and the use scene of the detection target simulation of various different input powers and different output powers can be flexibly met. The analog target amplitude can also be realized by adjusting the analog target parameter of the processing module 8, and further adjusting and controlling the amplitude of the intermediate frequency signal sent by the digital-to-analog conversion module 9.

In one embodiment, as shown in fig. 2, the signal receiving module 1 includes: a built-in circularly polarized receiving antenna 101, a first radio frequency switch 102 and a receiving radio frequency head 103; the first radio frequency switch 102 can select the built-in circularly polarized receiving antenna 101 or the receiving radio frequency head 103 and the external receiving antenna to receive electromagnetic wave signals emitted by the radar;

wherein, the built-in circularly polarized receiving antenna 101 is used for receiving electromagnetic wave signals in orthogonal directions;

the receiving rf head 103 is configured to be externally connected to a receiving antenna, so as to receive an electromagnetic wave signal through the receiving antenna; the receiving antenna is set according to the requirement.

The radio frequency switch 102 is connected to the built-in circularly polarized receiving antenna 101 and the receiving radio frequency head 103, and is configured to control a receiving antenna externally connected to the built-in circularly polarized receiving antenna 101 or the receiving radio frequency head 103 to correspondingly receive an X-band electromagnetic wave signal, so as to input the X-band electromagnetic wave signal to the low noise amplifier 2.

In one embodiment, as shown in fig. 2, the signal transmitting module 13 includes: a built-in circularly polarized transmitting antenna 131, a second radio frequency switch 132 and a transmitting radio frequency head 133; according to the method, the second radio frequency switch 132 can select the built-in circularly polarized transmitting antenna 131 or the transmitting radio frequency head 133 plus the external transmitting antenna to transmit the analog target signal to the radar sensor;

Wherein, the built-in circularly polarized transmitting antenna 131 is used for transmitting the analog target signal in the form of circularly polarized electromagnetic wave;

the transmitting rf head 133 is configured to be externally connected to a transmitting antenna, so as to transmit the analog target signal through the transmitting antenna; the transmitting antenna is set according to the requirements.

The radio frequency switch 132 is connected to the built-in circularly polarized transmitting antenna 131 and the transmitting radio frequency head 133, and is used for controlling the transmitting antenna externally connected to the built-in circularly polarized transmitting antenna 131 or the transmitting radio frequency head 133 to transmit the analog target signal.

In an embodiment, in order to prevent the problem of large difference in analog signal amplitude caused by different polarization directions of antennas of radar products, the problem of large signal difference between polarized deflection individuals caused by difference in spatial arrangement positions of the tested products when multiple tested radar products are measured is reduced.

And adopting the built-in circular polarization receiving antenna and the built-in circular polarization transmitting antenna to receive and transmit signals.

As shown in fig. 3a, the built-in circular polarized receiving antenna and the built-in circular polarized transmitting antenna are respectively embedded in the front surface (antenna surface) of the simulator circuit board, and as shown in fig. 3b, the back surface (feed network surface) of the simulator circuit board is respectively provided with a feed network which is matched with the built-in circular polarized receiving antenna and the built-in circular polarized transmitting antenna; the built-in circular polarization receiving antenna and the built-in circular polarization transmitting antenna are respectively provided with a first feeding point and a second feeding point, and the first feeding point and the second feeding point connect the antennas with the corresponding feeding network in a metal via way; the first feeding point and the second feeding point are equal in distance from the geometric center of the corresponding antenna, and connecting lines of the two feeding points to the geometric center are orthogonal to each other;

The built-in circularly polarized receiving antenna is combined with a corresponding feed network to acquire a received electromagnetic wave signal sent by an X-band radar sensor; and the built-in circularly polarized transmitting antenna is combined with a corresponding feed network to transmit the generated analog target signal to the X-band radar sensor in a circularly polarized electromagnetic wave mode.

Each feed network is provided with a power divider and a resistor; one end of the power divider is connected with a first feeding point and a second feeding point of the corresponding antenna, and the other end of the power divider is connected with the low-noise amplifier 2 or the second attenuator 12 arranged on the simulator circuit board; the resistor bridges the first specific position and the second specific position which are respectively arranged on the transmission sections from the first feeding point and the second feeding point to the power divider, and the resistance value of the resistor is twice the impedance value of the transmission microstrip line.

If the feed network is arranged corresponding to the built-in circular polarization receiving antenna, one end of the feed network is connected with a first feed point and a second feed point of the built-in circular polarization receiving antenna; the other end is connected with the low noise amplifier 2 after being combined by a power divider. If the feed network is arranged corresponding to the built-in circular polarization transmitting antenna, one end of the feed network is connected with a first feed point and a second feed point of the built-in circular polarization transmitting antenna; the other end is connected with a second attenuator 12 after passing through a power divider and combining; preferably, the power divider is a one-to-one second-power divider.

Preferably, the length of each section of transmission line of the feed network has special requirements. In order to synthesize an accurate circularly polarized electromagnetic wave, as shown in FIG. 4, the transmission segment length L between the first specific position A and the first feeding point 1 _A1 And a transmission segment length L between the second specific position B and the second feeding point 2 _B2 The first length relation is satisfied; and corresponds to the transmission section length L between the first specific position A and the power divider D _DA And a transmission section length L between the second specific position B and the power divider D _DB The second length relation is met to ensure that the phase difference relation of the two feed points is 90 degrees accurately, the power is equal, and the accurate circularly polarized electromagnetic wave is synthesized. A transmission section length L corresponding to the first specific position A to the second specific position B through a resistor R _ARB And a transmission section length L corresponding to the first specific position A passing through the power divider D and then reaching the second specific position B _ADB Satisfy the third lengthDegree relationship.

Wherein the first length relationship comprises:

and wherein lambda is the wavelength of electromagnetic wave in air at the radar working frequency, epsilon is the dielectric constant of the circuit board, and N is a natural number.

And the second length relation is corresponding to the transmission section length L between the first specific position A and the power divider D _DA And a transmission section length L between the second specific position B and the power divider D _DB Equal.

At this time, the phase difference between the two feeding points is 90 °, the power is equal, the electromagnetic waves excited respectively are a pair of linear polarized waves orthogonal to each other, and the synthesized wave form is a circular polarized wave.

The third length relationship includes:

and wherein L _ARB For the transmission section length L from the first specific position A to the second specific position B through the resistor R _ADB And for the length of a transmission section from the first specific position A to the second specific position B through the power divider D, lambda is the wavelength of electromagnetic waves in air at the radar working frequency, epsilon is the dielectric constant of a circuit board, and N is a natural number.

The feeding circuit in one embodiment may additionally employ a bridge, balun, phase shifter, etc.; the implementation of the built-in circular polarization receiving and transmitting antenna can additionally adopt other schemes such as antenna corner cutting, slotting and the like.

In one embodiment, as shown in fig. 2, the signal conversion and phase shift module 5 includes:

balun 51 for converting the conditioned signal from a single-ended signal to a differential signal;

and a phase shifter 52 connected to the balun 51 for shifting the phase of the converted differential signal and outputting a pair of orthogonal radio frequency signals.

In an embodiment, the frequency dividing module is a frequency divider, and is configured to perform frequency dividing processing; the frequency multiplication module is a frequency multiplier which is the same as the multiple of the frequency divider and is used for carrying out frequency multiplication processing which is consistent with the multiple of the frequency divider, namely up-converting the down-converted signal loaded with the target information of the simulator back.

In one embodiment, the X-band doppler radar target simulator is connected with a control end of an upper computer; further, as shown in fig. 1, the processing module 8 is connected to the upper computer control terminal 14, and is configured to set the simulation target parameter based on a control instruction of the upper computer control terminal 14, and generate a digital signal according with the simulation target feature.

The analog target parameters of the processing module 8 can be modified by the upper computer control end so as to modify the parameters of the digital-to-analog conversion module 9, and the frequency, amplitude and phase relation of the intermediate frequency signal 1 and the intermediate frequency signal 2 are adjusted so as to adjust the speed of the detection target, the amplitude of the target and whether the target is close or far.

In an embodiment, the X-band doppler radar target simulator is connected to the upper computer control end 14 through a USB interface, the upper computer control end 14 identifies a serial port of the X-band doppler radar target simulator through the connected USB interface, and parameters in the processing module 8 can be modified through the serial port to adjust simulation target characteristics, the parameters are modified in real time and can be saved in a power-off mode according to needs, and if the simulation target parameters are not required to be modified next time, the upper computer can not be used to modify the target parameters. In the implementation process of the scheme, the low-power consumption design is considered, the USB of the control end of the upper computer can be used for supplying power, and the cost of a direct-current power supply is not required to be increased additionally.

In order to better illustrate the above-described X-band doppler radar target simulator, the present invention provides the following specific embodiments.

Example 1: an X-band Doppler radar target simulator. Fig. 5 is a schematic structural diagram of an X-band doppler radar target simulator in an embodiment.

The X-band Doppler radar target simulator comprises: the device comprises a receiving antenna, a radio frequency switch, a receiving radio frequency head, a transmitting antenna, a transmitting radio frequency head, a low noise amplifier, a frequency divider, a first attenuator, a balun and a phase shifter, a first mixer, a second mixer, a microprocessor, a digital-to-analog conversion module, a combiner, an upper computer control end and a self-lapping set software tool;

the receiving antenna or the receiving radio frequency head is added with an external receiving antenna to receive electromagnetic wave signals emitted by a radar, the signals are amplified by a low noise amplifier, then the radio frequency is down-converted to a radio frequency band working in a circuit between the frequency divider and the frequency multiplier through the frequency divider, the amplitude of the radio frequency electromagnetic wave signals after frequency division is adjusted through an attenuator, and then the signals are converted into a pair of orthogonal radio frequency signals from single-ended signals through a balun and a phase shifter; meanwhile, the microprocessor outputs a digital signal which accords with the analog target characteristics according to preset parameters, the digital signal is converted into a pair of baseband analog orthogonal signals which accord with the analog target characteristics through a digital-to-analog converter, the pair of signals are mixed with the orthogonal radio frequency signals through mixers 1 and 2 respectively, then the two paths of signals are added through a combiner, then the down-conversion signal loaded with the target information of the simulator is up-converted back through a frequency multiplier (namely, the frequency multiplier is required to be consistent with the frequency divider multiple), the output signal is attenuated appropriately through an attenuator to meet the target analog amplitude requirement, and then the analog target signal is returned to the radar through a transmitting antenna or a transmitting radio frequency head and an external transmitting antenna. If the target characteristic parameters need to be modified, an upper computer end tool of the self-grinding matching sleeve can be used for modifying the internal parameters of the microprocessor through a serial port to adjust the simulation target characteristics, the parameter modification takes effect in real time and can be powered down and stored according to the needs, and if the simulation target parameters do not need to be modified next time, the upper computer can be omitted.

The built-in receiving and transmitting circularly polarized antenna adopts an on-board antenna with a 90-degree phase-shifting power divider and a double-hole back feed, the scheme is low in cost, easy to realize, high in consistency and convenient to use, and the problem that simulation targets are large in difference due to antenna polarization direction difference in the research and development and testing processes of radar products is solved.

In this embodiment, after the circular polarization is disassembled into two orthogonal linear polarizations, the ratio of the magnitudes of the two linear polarizations is referred to as the axial ratio. In the general circular polarization design, when the general axial ratio is less than or equal to 3dB, the circular polarization design requirement is considered to be met. And fig. 6 shows the axial ratio index of the circularly polarized antenna in each main direction angle, and it can be seen that the axial ratio index in the scheme is basically kept below 1dB, and the circular polarization strictness is higher than the general standard.

Fig. 7 shows a schematic diagram of an application test environment of an X-band doppler radar sensing test system according to an embodiment of the present invention.

The X-band Doppler radar target simulator can be applied to target simulation of a single radar sensor product, such as test analysis of the signal processing capability of the radar sensor product in the research and development process; the method can also be simultaneously applied to target simulation of a plurality of radar sensor products, such as production test of a plurality of radar sensor products;

The system is in an external environment built by wave absorbing materials, comprising:

one or more X-band doppler radar sensors 71 mounted on a tool plane of the fixed tool 01;

an X-band doppler radar target simulator 72 installed in a normal direction along the tool plane as a target simulator of the test system; it should be noted that the X-band doppler radar target simulator 72 may implement all the functions of the X-band doppler radar target simulator in the above embodiment, which will not be described in detail. In addition, the X-band doppler radar target simulator 72 is further connected to the control end of the upper computer through a USB interface by using a USB power supply serial communication line.

It should be noted that, in the tool design for testing the X-band doppler radar sensor 71, a mode of spreading along a plane is adopted in most cases, and the target simulator is disposed in a normal direction of the plane, so that the difference of detection results is small. However, the form of spreading the X-band doppler radar sensor 71 is not limited to equidistant spreading, and in theory, the X-band doppler radar sensor 71 may be spaced apart from each other by a certain distance, and there is no requirement on the regularity of orientation and arrangement.

The X-band doppler radar target simulator 72 simulates the target speed and the target amplitude of the simulated target based on the received electromagnetic waves transmitted by the X-band doppler radar sensors 71 and the simulated target parameters related to the simulated target, and returns the simulated target signals corresponding to the target speed and the target amplitude of the simulated target to the corresponding X-band doppler radar sensors 71.

Because the installation position of the X-band Doppler radar sensor has non-negligible dislocation relative to the target simulator, signal receiving and transmitting are not strictly transmitted according to the normal direction, so that polarization deflection exists; according to the scheme, the X-band Doppler radar target simulator 72 is adopted, signals can be received and transmitted in a mode of reducing half power for any deflected X-band Doppler radar sensor through circular polarization, and the X-band Doppler radar target simulator 72 corresponds to a plurality of X-band Doppler radar sensors and can receive and transmit signals with consistent amplitude.

In one embodiment, as shown in fig. 7, the X-band doppler radar target simulator 61 is mounted in a direction normal to the tool plane at a distance d from the tool plane. D satisfies a fixed distance relationship;

wherein the fixed distance relationship comprises:

and D is the diagonal length of the fixture for fixing the Doppler radar sensor in the X wave band, and lambda is the wavelength in the air corresponding to the electromagnetic wave under the working frequency of the radar.

In a specific embodiment, 9X-band doppler radar sensors and an X-band doppler radar target simulator are used for testing, and the 9X-band doppler radar sensors are mounted on a fixed tool, and are spread out in a nine-grid plane as shown in fig. 8; the target simulator adopts an X-band Doppler radar target simulator, and is arranged in the normal direction along the plane of the tool, the distance from the tool is d, and the d value meets the corresponding formula (13);

For a simulator of linear polarization design, facing the problem of polarization deflection, only electromagnetic wave components consistent with the self polarization direction can be reserved for receiving and transmitting, and components different from the self direction are abandoned; the proportion of the selection is changed according to different deflection degrees, and finally the magnitude of the received transmitting signal of the simulator is caused to fluctuate. Under the design of circular polarization, the received and emitted electromagnetic waves of the X-band Doppler radar target simulator can be disassembled into any two equal-amplitude orthogonal linear polarizations, wherein one polarization coincides with the deflected radar electromagnetic waves, and the other polarization is orthogonal with the deflected radar electromagnetic waves; therefore, for any deflected radar electromagnetic wave, the circular polarization can transmit and receive signals in a mode of reducing half power, so that the simulator corresponds to a plurality of X-wave band Doppler radar sensors, and signals with consistent amplitude can be transmitted and received.

Thus, compared with the prior art, the invention has the following advantages:

1. based on the technical scheme of the invention, the microwave radar testing scheme is more economical and flexible, has better scene repeatability and controllability, is changed from the previous qualitative measurement of a random target scene to the quantitative measurement of fixed target information, and plays an important role in the research and development of the radar, the problem analysis and the production process.

2. The technical scheme provided by the invention comprises a design of the built-in circularly polarized antenna, so that the harsh requirement on the polarization direction of the antenna of the radar product is reduced in the use process, and the problem of large performance difference of the simulation target caused by improper placement of the polarization direction of the antenna of the radar product is solved. In a batch radar product testing scene, the problem of large performance difference of simulation targets caused by position difference of batch radar products is also reduced, and the consistency of results of batch testing is improved.

3. Based on the use of the frequency division module and the frequency multiplication module, the X wave band is converted into a more common C wave band or S wave band for signal processing, so that the requirements on PCB materials and impedance control are reduced, and the gain loss caused by PCB microstrip routing is reduced; meanwhile, the use of the X-band radio frequency element can be reduced, the C-band or S-band element is used for processing the intermediate radio frequency signal, and the C-band or S-band element is relatively more common and has lower cost; in addition, more importantly, as shown in the formula (2), the Doppler frequency corresponding to the same target speed is higher than the C-band or S-band due to the higher radio frequency of the X-band, namely the frequency of the intermediate frequency signal to be simulated by the digital-to-analog converter is proportionally increased, so that the high-speed digital-to-analog converter is required to generate the intermediate frequency signal, and the development difficulty and cost are increased; according to the target speed simulation deduction formulas (6) and (10), after the frequency multiplier is adopted, the frequency of the intermediate frequency signal is multiplied, namely the frequency of the intermediate frequency signal generated by the digital-to-analog converter is reduced by times at the same speed as the simulation target, so that the pressure of the intermediate frequency signal with very high frequency required to be output by the digital-to-analog converter is reduced, a high-speed digital-to-analog converter is not required, and development difficulty and development cost are further reduced.

4. Based on the technical scheme of the invention, the high-integration and miniaturized design is adopted, the portable and portable shielding device is convenient to carry and install, no obstacle is caused when the portable and miniaturized shielding device is used in a narrow environment, the relative size of the corresponding shielding environment can be relatively small, and the space and cost of the shielding environment are saved.

In summary, according to the X-band doppler radar target simulator and the X-band doppler radar sensing test system, according to the doppler radar principle, after receiving the X-band electromagnetic wave signal, the circuit of the X-band doppler radar target simulator generates and returns an echo signal containing detection target information to the X-band electromagnetic wave radar, so that the speed information and amplitude information of the radar echo signal are accurately set by a given amount, adjustable and repeatable target signal which is difficult to quantify, inflexible and poor in repeatability in the prior art; in addition, the invention realizes the conversion of the X-band electromagnetic wave signal to the C-band or S-band for subsequent signal processing by arranging the frequency division module and the frequency multiplication module which adopt the same multiple, so that not only can the C-band or S-band element be used for processing the intermediate radio frequency signal, but also a high-speed digital-to-analog converter is not required to be used for generating the intermediate frequency signal, thereby reducing the development difficulty and the development cost.

The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. It is therefore intended that all equivalent modifications and changes made by those skilled in the art without departing from the spirit and technical spirit of the present invention shall be covered by the appended claims.

Claims

1. An X-band doppler radar target simulator for simulating a target speed and a target amplitude of a detection target, the target simulator comprising:

the device comprises an X-band signal receiving module, a low-noise amplifier, a frequency dividing module, a first attenuation module, a signal conversion and phase shift module, a first mixer, a second mixer, a processing module, a digital-to-analog conversion module, a combiner, a frequency multiplication module, a second attenuator and a signal transmitting module;

the X-band signal receiving module, the low-noise amplifier, the frequency dividing module, the first attenuator and the signal conversion and phase shift module are sequentially connected in series; the first mixer and the second mixer are respectively connected with the signal conversion and phase shift module, the digital-to-analog conversion module and the combiner; the processing module is connected with the digital-to-analog conversion module; the combiner, the frequency multiplication module, the second attenuator and the signal transmitting module are sequentially connected in series;

The frequency division module and the frequency multiplication module adopt the same multiple and are used for converting the X-band electromagnetic wave signal into a C-band or S-band for subsequent signal processing and converting the processed C-band or S-band signal into an X-band;

the signal receiving module receives an X-band electromagnetic wave signal sent by the X-band Doppler radar sensor, the low-noise amplifier amplifies the X-band electromagnetic wave signal, the frequency division module is used for down-converting the radio frequency of the signal to a radio frequency band of a circuit work between the frequency division module and the frequency multiplication module, and the first attenuator is used for adjusting the electromagnetic wave amplitude of the radio frequency electromagnetic wave signal after the frequency division; the signal conversion and phase shift module converts the regulated signal from a single-ended signal to a differential signal and outputs a pair of orthogonal radio frequency signals; converting, by the digital-to-analog conversion module, a pair of baseband analog quadrature signals that conform to the analog target characteristics according to the digital signals that conform to the analog target characteristics generated by the processing module based on the analog target parameters related to the detection target; the first mixer and the second mixer respectively mix the baseband analog quadrature signal with the radio frequency signal output by the signal conversion and phase shift module, and then add the signals mixed by the first mixer and the second mixer through the combiner; and the added signals are subjected to frequency multiplication processing through the frequency multiplication module, then subjected to signal amplitude adjustment through the second attenuator, and returned to the X-band Doppler radar sensor through the signal transmitting module according with the target speed and the target amplitude of the detected target.

2. The X-band doppler radar target simulator of claim 1, wherein the means for simulating the target speed of the probe target comprises:

the digital-to-analog conversion module changes parameters of the digital-to-analog conversion module according to digital signals generated by the processing module based on analog target parameters related to the target speed of a detection target, the digital-to-analog conversion module converts the digital-to-analog conversion module into baseband analog quadrature signal pairs conforming to the target frequency or the target phase, the baseband analog quadrature signal pairs are mixed with radio frequency signals output by the signal conversion and phase shift module through the first mixer and the second mixer respectively, and the mixed signals of the first mixer and the second mixer are added through the combiner, so that the added signals are subjected to frequency multiplication processing and signal amplification through the frequency multiplication module and the second attenuator in sequence to generate analog target signals conforming to the target speed;

3. The X-band doppler radar target simulator of claim 1, wherein the means for simulating the target amplitude of the probe target comprises:

and adjusting the amplitude of the signal by setting one or more of parameters of a low noise amplifier, a frequency division module, a frequency multiplication module, a first attenuator, a second attenuator and a digital-to-analog conversion module, so as to generate an analog target signal of the output power which accords with the target amplitude.

4. The X-band doppler radar target simulator of claim 1, wherein the signal receiving module comprises: a circular polarization receiving antenna, a first radio frequency switch and a receiving radio frequency head are arranged in the antenna;

the built-in circularly polarized receiving antenna is used for receiving electromagnetic wave signals in the orthogonal direction;

the receiving radio frequency head is used for externally connecting a receiving antenna so as to receive electromagnetic wave signals through the receiving antenna;

the radio frequency switch is connected with the built-in circularly polarized receiving antenna and the receiving radio frequency head and is used for controlling the built-in circularly polarized receiving antenna or the receiving antenna externally connected with the receiving radio frequency head to correspondingly receive the X-band electromagnetic wave signal so as to input the X-band electromagnetic wave signal into the low noise amplifier.

5. The X-band doppler radar target simulator of claim 1, wherein the signal transmitting module comprises: a circular polarization transmitting antenna, a second radio frequency switch and a transmitting radio frequency head are arranged in the antenna;

the built-in circularly polarized transmitting antenna is used for transmitting a simulated target signal in the form of circularly polarized electromagnetic waves;

the transmitting radio frequency head is used for being externally connected with a transmitting antenna so as to transmit the analog target signal through the transmitting antenna;

the radio frequency switch is connected with the built-in circular polarization transmitting antenna and the transmitting radio frequency head and is used for controlling the transmitting antenna externally connected with the built-in circular polarization transmitting antenna or the transmitting radio frequency head to transmit the simulation target signal.

6. The X-band doppler radar target simulator according to claim 4 or 5, wherein the built-in circular polarization receiving antenna and the built-in circular polarization transmitting antenna are respectively embedded in the front surface of a simulator circuit board of the X-band doppler radar target simulator, and a feed network matched with the built-in circular polarization receiving antenna and the built-in circular polarization transmitting antenna is respectively arranged on the back surface of the simulator circuit board; the built-in circular polarization receiving antenna and the built-in circular polarization transmitting antenna are respectively provided with a first feeding point and a second feeding point, and the first feeding point and the second feeding point connect the antennas with the corresponding feeding network in a metal via way; the first feeding point and the second feeding point are equal in distance from the geometric center of the corresponding antenna, and connecting lines of the two feeding points to the geometric center are orthogonal to each other;

The built-in circularly polarized receiving antenna is combined with a corresponding feed network to receive an X-band electromagnetic wave signal sent by an X-band Doppler radar sensor; the built-in circularly polarized transmitting antenna is combined with a corresponding feed network to send the generated simulated target signal to a corresponding X-band Doppler radar sensor in a circularly polarized electromagnetic wave mode.

7. The X-band doppler radar target simulator of claim 1, wherein the signal conversion and phase shift module comprises:

balun for converting the regulated signal from a single-ended signal to a differential signal;

and the phase shifter is connected with the balun and used for shifting the phase of the converted differential signal and outputting a pair of orthogonal radio frequency signals.

8. The X-band doppler radar target simulator of claim 1, wherein the processing module is configured to set the simulation target parameter based on a control command of a host computer control terminal connected to the X-band radar target simulator, and generate a digital signal conforming to a characteristic of the simulation target.

9. The X-band doppler radar target simulator of claim 1, wherein the frequency dividing module is a frequency divider and the frequency doubling module is a frequency multiplier; the frequency divider and the frequency multiplier adopt the same multiple.

10. An X-band doppler radar sensing test system, the system comprising:

one or more X-band Doppler radar sensors are respectively arranged on the tool plane of the fixed tool;

the X-band doppler radar target simulator of any one of claims 1 to 9 mounted in a direction normal to the tool plane;

the X-band Doppler radar target simulator simulates the target speed and the target amplitude of the detected target based on the received X-band electromagnetic wave signals transmitted by the X-band Doppler radar sensors and the simulated target parameters related to the detected target, and returns the simulated target signals conforming to the target speed and the target amplitude of the detected target to the corresponding X-band Doppler radar sensors so that the X-band Doppler radar sensors can acquire the target speed and the target amplitude of the detected target based on the received simulated target signals.