Radar target simulator based on mixing mode and microwave radar sensor test system

Abstract

The present invention provides a radar target simulator based on a frequency mixing method and a microwave radar sensor test system. After receiving the electromagnetic wave signal of the radar sensor, the radar target simulator circuit based on the frequency mixing method generates and returns an echo signal containing the detection target information to the radar sensor. Through the radar's processing ability of the echo signal, it is deduced whether the function of the radar in the actual scene can meet the use requirements. The target signal that is difficult to quantify, inflexible and has poor repeatability in the prior art is given, adjustable and repeatable, and the target feature information of the radar echo signal is accurately set, so that the microwave radar test is more economical and flexible, and the scene repeatability and controllability are better.

Description

Technical Field

[0001] The invention relates to the field of radar, and in particular to a radar target simulator based on a frequency mixing mode and a microwave radar sensor test system. Background Art

[0002] With the gradual deepening of the transformation of radar technology from military to civilian use, microwave radar, as a sensor, is used in a variety of consumer products. Microwave radar sensors can be installed secretly and are not affected by temperature, airflow, dust and smoke. They have the advantages of long life, fast response speed, higher sensitivity and wide sensing area. They have gradually replaced infrared, voice control and other sensing technologies and are widely used in consumer electronic products in many fields, including energy-saving lighting, security, smart home appliances, etc. In the research and development and production process of these microwave radar products, the performance detection of microwave radar is a very important link.

[0003] For current energy-saving lighting, security, smart home appliances and other products, the civilian microwave radar sensor test solution usually uses angle-reflected antennas, wobblers, people walking or waving as detection targets for testing radar sensors. The disadvantage of this method is that the test results are perceptual and difficult to quantify, not flexible enough and with poor repeatability. Especially in production testing, when multiple radar sensor products are tested against targets, such a solution will amplify the deviation of the sensing results of different radar sensors, resulting in a deterioration of consistency, and cannot truly test the true performance of the radar product. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a radar target simulator based on a frequency mixing method and a microwave radar sensor test system, so as to solve the above technical problems in the prior art.

[0005] To achieve the above-mentioned purpose and other related purposes, the present invention provides a radar target simulator based on a mixing method, which is used to simulate the detection target. The target simulator includes: a signal receiving module, a low-noise amplifier, a first attenuator, a low-pass filter module, a first mixer, a second mixer, a processing module, a first local oscillator generator, a second local oscillator generator, a high-pass filter module, a second attenuator, a power amplifier and a signal transmitting module; wherein the signal receiving module, the low-noise amplifier, the first attenuator, the first mixer, the low-pass filter module, the second mixer, the high-pass filter module, the second attenuator and the power amplifier are connected in series in sequence; the first mixer is connected to the first local oscillator generator, and the second mixer is connected to the second local oscillator generator; the processing module is respectively connected to the first local oscillator generator and the second local oscillator generator; the signal receiving module receives the electromagnetic wave signal sent by the radar sensor, and then transmits it in sequence through the low-noise amplifier and the first local oscillator generator. An attenuator amplifies the electromagnetic wave signal and adjusts the electromagnetic wave amplitude; the first mixer converts the signal output by the first local oscillator generator, which is preset by the processing module based on the corresponding set simulated target parameters, and the signal output by the first attenuator into an intermediate frequency signal, and the high-frequency signal part of the signal output by the first mixer is filtered out through a low-pass filter module and the low-frequency signal part is retained, and then the second mixer converts the signal output by the second local oscillator generator, which is preset by the processing module based on the corresponding set simulated target parameters, and the signal output by the low-pass filter module are mixed, and then the high-pass filter module is used to filter out the low-frequency signal part of the signal output by the second mixer and the high-frequency signal part is retained, and then the second attenuator and the power amplifier are sequentially used to amplify the signal and adjust the electromagnetic wave amplitude, and the signal transmission module returns the simulated target signal that meets the simulated target to the radar sensor.

[0006] In one embodiment of the present invention, the radar target simulator is used to simulate the target speed and target amplitude of the Doppler radar detection target, so as to return the simulated target signal that meets the requirements of the Doppler radar detection target to the corresponding Doppler radar sensor.

[0007] In one embodiment of the present invention, the method of simulating the target speed of the target detected by the Doppler radar includes: changing the preset parameters of the first local oscillator generator to output a signal of a corresponding frequency according to the digital signal generated by the processing module based on the first simulated target parameter related to the target speed detected by the Doppler radar through the first local oscillator generator, and then converting the signal output by the first local oscillator generator and the signal output by the first attenuator into an intermediate frequency signal through the first mixer, filtering out the high-frequency signal part of the signal output by the first mixer and retaining the low-frequency signal part through the low-pass filtering module, and then converting the first local oscillator generator into an intermediate frequency signal according to the digital signal generated by the processing module based on the first simulated target parameter related to the target speed detected by the Doppler radar through the second mixer. The digital signal generated by the second analog target parameter related to the target speed of the detected target changes the preset parameter of the second local oscillator generator to output a signal of a corresponding frequency, and performs frequency conversion mixing with the signal output by the low-pass filter module, and then the low-frequency signal part of the signal output by the second mixer is filtered out by the high-pass filter module and the high-frequency signal part is retained, and then the signal is amplified and the electromagnetic wave amplitude is adjusted by the second attenuator and the power amplifier in sequence to generate an analog target signal that meets the target speed of the target detected by the Doppler radar; wherein, the first analog target parameter and the second analog target parameter are set to change the frequency of the output signal of the first local oscillator generator and the second local oscillator generator to generate an analog target signal that meets the target speed of the target detected by the Doppler radar.

[0008] In one embodiment of the present invention, the target simulator simulates the target amplitude of the Doppler radar detection target by adjusting the signal amplitude by one or more methods of setting the parameters of the low-noise amplifier, the first attenuator, the second attenuator, and the power amplifier to generate a simulated target signal with an output power that meets the target amplitude.

[0009] In one embodiment of the present invention, the radar target simulator also includes: a phase control circuit connected between the power amplifier and the signal transmission module; the radar target simulator is used to simulate the detection target distance, target speed and target amplitude of the frequency modulated continuous wave radar detection target, so as to return the simulated target signal that meets the frequency modulated continuous wave radar detection target to the corresponding frequency modulated continuous wave radar sensor.

[0010] In one embodiment of the present invention, a method for simulating the detection target distance of a frequency modulated continuous wave radar detection target includes: changing the preset parameters of the first local oscillator generator to output a signal of a corresponding frequency according to a digital signal generated by the processing module based on a third simulated target parameter related to the detection target distance of the frequency modulated continuous wave radar detection target through the first local oscillator generator, and then converting the signal output by the first local oscillator generator and the signal output by the first attenuator into an intermediate frequency signal through the first mixer, filtering out the high-frequency signal part of the signal output by the first mixer and retaining the low-frequency signal part through a low-pass filtering module, and then converting the signal generated by the first local oscillator generator based on a fourth simulated target parameter related to the detection target distance of the frequency modulated continuous wave detection target through the second mixer. The digital signal changes the preset parameters of the second local oscillator generator to output a signal of a corresponding frequency, and performs frequency conversion mixing with the signal output by the low-pass filter module. The low-frequency signal part of the signal output by the second mixer is filtered out by the high-pass filter module and the high-frequency signal part is retained. The signal is then amplified and the electromagnetic wave amplitude is adjusted by the second attenuator and the power amplifier in sequence. The phase of the output signal is adjusted by the phase control circuit to generate an analog target signal that meets the detection target distance of the frequency modulated continuous wave radar. The frequencies of the output signals of the first local oscillator generator and the second local oscillator generator are changed by setting the third analog target parameter and the fourth analog target parameter to generate an analog target signal with an intermediate frequency beat signal frequency that meets the detection target distance, so as to generate an analog target signal that meets the detection target distance of the frequency modulated continuous wave radar.

[0011] In one embodiment of the present invention, the method for simulating the target speed of a target detected by a frequency modulated continuous wave radar includes: changing the preset parameters of the first local oscillator generator to output a signal of a corresponding phase according to the digital signal generated by the processing module based on the fifth simulated target parameter related to the target speed detected by the frequency modulated continuous wave radar through the first local oscillator generator, and then converting the signal output by the first local oscillator generator and the signal output by the first attenuator into an intermediate frequency signal through the first mixer, filtering out the high-frequency signal part of the signal output by the first mixer and retaining the low-frequency signal part through a low-pass filtering module, and then changing the first local oscillator generator to output a signal of a corresponding phase according to the digital signal generated by the processing module based on the sixth simulated target parameter related to the target speed detected by the frequency modulated continuous wave radar through the second mixer. The signal of the corresponding phase output by the preset parameters of the local oscillator generator is frequency-converted and mixed with the signal output by the low-pass filter module, and then the low-frequency signal part of the signal output by the second mixer is filtered out by the high-pass filter module and the high-frequency signal part is retained, and then the signal is amplified and the electromagnetic wave amplitude is adjusted by the second attenuator and the power amplifier in sequence, and the phase of the output signal is adjusted by the phase control circuit corresponding to a phase parameter to generate a simulated target signal that meets the target speed of the frequency modulated continuous wave radar detection target; wherein, the phases of the output signals of the first local oscillator generator and the second local oscillator generator are changed by setting the fifth simulated target parameter and the sixth simulated target parameter, and then the phase parameters of the phase control circuit are set to generate a simulated target signal of the intermediate frequency beat signal phase that meets the target speed, so as to generate a simulated target signal that meets the target speed of the frequency modulated continuous wave radar detection target.

[0012] In one embodiment of the present invention, the processing module is used to set the simulated target parameters based on control instructions from a host computer control terminal connected to the radar target simulator, and generate a digital signal that meets the simulated target characteristics.

[0013] In one embodiment of the present invention, a method for simulating a target amplitude of a frequency modulated continuous wave radar detection target includes: adjusting the signal amplitude by setting one or more of the parameters of a low noise amplifier, a first attenuator, a second attenuator, and a power amplifier to generate a simulated target signal with an output power that meets the target amplitude.

[0014] In one embodiment of the present invention, the signal receiving module includes: a built-in circularly polarized receiving antenna, a first radio frequency switch and a receiving radio frequency head; wherein the built-in circularly polarized receiving antenna is used to receive electromagnetic wave signals in orthogonal directions; the receiving radio frequency head is used to externally connect a receiving antenna to receive electromagnetic wave signals through the receiving antenna; the first radio frequency switch is connected to the built-in circularly polarized receiving antenna and the receiving radio frequency head, and is used to control the corresponding electromagnetic wave signal received by the built-in circularly polarized receiving antenna or the receiving antenna externally connected to the receiving radio frequency head, so as to input the electromagnetic wave signal into the low noise amplifier.

[0015] In one embodiment of the present invention, the signal transmission module includes: a built-in circularly polarized transmitting antenna, a second radio frequency switch and a transmitting radio frequency head; wherein the built-in circularly polarized transmitting antenna is used to transmit an analog target signal in the form of a circularly polarized electromagnetic wave; the transmitting radio frequency head is used to connect an external transmitting antenna to transmit the analog target signal through the transmitting antenna; the second radio frequency switch is connected to the built-in circularly polarized transmitting antenna and the transmitting radio frequency head, and is used to control the transmission of the analog target signal by the built-in circularly polarized transmitting antenna or the transmitting antenna externally connected to the transmitting radio frequency head.

[0016] In one embodiment of the present invention, the processing module is used to set the simulated target parameters based on control instructions from a host computer control terminal connected to the radar target simulator, and generate a digital signal that meets the characteristics of the simulated target.

[0017] To achieve the above-mentioned purpose and other related purposes, the present invention provides a microwave radar sensor testing system, which includes: radar sensors, which are respectively installed on the tooling plane of the fixed tooling; the radar target simulator is installed in the normal direction along the tooling plane; wherein the radar target simulator simulates the detection target based on the received electromagnetic wave signal emitted by the radar sensor and the simulated target parameters related to the detection target, and returns each simulated target signal that meets the detection target to the corresponding radar sensor.

[0018] As described above, the present invention is a radar target simulator based on a frequency mixing method and a microwave radar sensor test system, which has the following beneficial effects: after receiving the electromagnetic wave signal of the radar sensor, the radar target simulator circuit based on the frequency mixing method generates and returns an echo signal containing the detection target information to the radar sensor, and the radar's processing ability of the echo signal is used to deduce whether the function of the radar in the actual scene can meet the use requirements. The target signal that is difficult to quantify, inflexible and has poor repeatability in the prior art is given, adjustable and repeatable, and the target feature information of the radar echo signal is accurately set, making the microwave radar test more economical and flexible, and the scene repeatability and controllability are better. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Shown is a schematic structural diagram of a radar target simulator based on a mixing method in one embodiment of the present invention.

[0020] Figure 2 Shown is a diagram showing the relationship between the transmission frequency and time of an FMCW radar in one embodiment of the present invention.

[0021] Figure 3 Shown is a schematic structural diagram of a radar target simulator based on a mixing method in one embodiment of the present invention.

[0022] Figure 4 Shown is a schematic diagram of the relationship between the sending signal and the receiving signal and time in an embodiment of the present invention.

[0023] Figure 5 Shown is a schematic diagram of the relationship between the intermediate frequency signal and time of a frequency modulated continuous wave radar in one embodiment of the present invention.

[0024] Figure 6 Shown is a schematic diagram of the relationship between the input signal, output signal and time of a frequency modulated continuous wave radar target simulator in one embodiment of the present invention.

[0025] Figure 7 Shown is a schematic structural diagram of a radar target simulator based on a mixing method in one embodiment of the present invention.

[0026] Figure 8 Shown is a schematic structural diagram of a radar target simulator based on a mixing method in one embodiment of the present invention.

[0027] Fig. 9 Shown is a schematic diagram of an application test environment of a microwave radar sensor test system in an embodiment of the present invention.

[0028] Fig.10 Shown is a schematic diagram of installing a Doppler radar sensor in one embodiment of the present invention.

[0029] Fig.11 It is a schematic diagram showing the axial ratio index of the circularly polarized antenna at each main direction angle in one embodiment of the present invention.

[0030] Fig.12 Shown is a schematic diagram of an application test environment of a microwave radar sensor test system in an embodiment of the present invention.

[0031] Fig.13 Shown is a schematic diagram of installing a FMCW radar sensor in an embodiment of the present invention.

[0032] Fig.14It is a schematic diagram showing the axial ratio index of the circularly polarized antenna at each main direction angle in one embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0034] It should be noted that in the following description, reference is made to the accompanying drawings, which describe several embodiments of the present invention. It should be understood that other embodiments may also be used, and that mechanical composition, structural, electrical and operational changes may be made without departing from the spirit and scope of the present invention. The following detailed description should not be considered restrictive, and the scope of the embodiments of the present invention is limited only by the claims of the published patents. The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. Spatially related terms, such as "upper", "lower", "left", "right", "below", "below", "lower", "above", "upper", etc., may be used in the text to facilitate the description of the relationship between an element or feature shown in the figure and another element or feature.

[0035] Throughout the specification, when a part is said to be "connected" to another part, this includes not only the case of "direct connection" but also the case of "indirect connection" by placing other elements therebetween. In addition, when a part is said to "include" a certain constituent element, unless otherwise stated, it does not exclude other constituent elements, but means that other constituent elements may be included.

[0036] The terms first, second and third mentioned herein are used to describe various parts, components, regions, layers and / or segments, but are not limited thereto. These terms are only used to distinguish a certain part, component, region, layer or segment from other parts, components, regions, layers or segments. Therefore, the first part, component, region, layer or segment described below may refer to the second part, component, region, layer or segment within the scope of the present invention.

[0037] Furthermore, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless there is an indication to the contrary in the context. It should be further understood that the terms "comprise", "include" indicate the presence of the described features, operations, elements, components, items, kinds, and / or groups, but do not exclude the presence, occurrence or addition of one or more other features, operations, elements, components, items, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Therefore, "A, B or C" or "A, B and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B and C". Exceptions to this definition will only occur when the combination of elements, functions or operations is inherently mutually exclusive in some way.

[0038] The present invention provides a radar target simulator based on a frequency mixing method and a microwave radar sensor test system. After receiving the electromagnetic wave signal of the radar sensor, the radar target simulator circuit based on the frequency mixing method generates and returns an echo signal containing the detection target information to the radar sensor. Through the radar's processing ability of the echo signal, it is deduced whether the function of the radar in the actual scene can meet the use requirements. The target signal that is difficult to quantify, inflexible and has poor repeatability in the prior art is given, adjustable and repeatable, and the target feature information of the radar echo signal is accurately set, so that the microwave radar test is more economical and flexible, and the scene repeatability and controllability are better.

[0039] The following is a detailed description of the embodiments of the present invention with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. The present invention can be embodied in many different forms and is not limited to the embodiments described herein.

[0040] A radar target simulator based on a mixing method in an embodiment of the present invention comprises: a signal receiving module, a low noise amplifier, a first attenuator, a low pass filter module, a first mixer, a second mixer, a processing module, a first local oscillator generator, a second local oscillator generator, a high pass filter module, a second attenuator, a power amplifier and a signal transmitting module;

[0041] The signal receiving module, the low noise amplifier, the first attenuator, the first mixer, the low pass filter module, the second mixer, the high pass filter module, the second attenuator, and the power amplifier are connected in series in sequence; the first mixer is connected to the first local oscillator generator, and the second mixer is connected to the second local oscillator generator; the processing module is connected to the first local oscillator generator and the second local oscillator generator respectively;

[0042] The signal receiving module receives the electromagnetic wave signal sent by the radar sensor, and then the electromagnetic wave signal is amplified and the electromagnetic wave amplitude is adjusted through the low noise amplifier and the first attenuator in turn; the signal output by the first local oscillator generator whose preset parameters are set by the processing module based on the corresponding set simulated target parameters and the signal output by the first attenuator are frequency-converted to intermediate frequency signals through the first mixer, and the high-frequency signal part of the signal output by the first mixer is filtered out through the low-pass filter module and the low-frequency signal part is retained, and then the signal output by the second local oscillator generator whose preset parameters are set by the processing module based on the corresponding set simulated target parameters and the signal output by the low-pass filter module are frequency-converted and mixed through the second mixer, and the low-frequency signal part of the signal output by the second mixer is filtered out through the high-pass filter module and the high-frequency signal part is retained, and then the signal is amplified and the electromagnetic wave amplitude is adjusted through the second attenuator and the power amplifier in turn, and the simulated target signal that meets the simulated target is returned to the radar sensor by the signal transmitting module.

[0043] The processing module may be a microprocessor MCU, or FPGA and other solutions may be used. This solution does not require the use of a very high-end microprocessor, thus reducing the difficulty and cost of software development.

[0044] Preferably, the simulator circuit board PCB size is only 100*60mm, with low requirements for the use environment space, achieving a highly integrated and miniaturized design.

[0045] In order to better describe the specific method of simulating the detection target by the radar target simulator based on the mixing method, it is now explained in conjunction with the following specific embodiments.

[0046] First, the radar target simulator of the present invention can be applied to the target simulation of Doppler radar. The simulation method of the Doppler radar detecting target by the present solution is introduced below.

[0047] Doppler radar, also known as continuous wave radar, is a common radar that emits a fixed RF frequency. Doppler radar can detect moving targets and the speed of the target. When the target moves, the RF signal emitted by the radar returns to the radar through the target surface, which will produce a Doppler effect, causing the signal received by the radar to shift in frequency. The radar can calculate the speed of the moving target through the RF frequency and the magnitude of the frequency shift. By comparing the frequency of the returned RF signal with that of the emitted RF signal, whether it is approaching or moving away from the radar can be determined.

[0048] like Figure 1 A schematic structural diagram of a radar target simulator based on a mixing method in an embodiment of the present invention is shown.

[0049] The radar target simulator based on the frequency mixing method is used to simulate the detection target of the Doppler radar.

[0050] The radar target simulator based on the mixing method includes: a signal receiving module 1 integrated on the simulator circuit board, a low-noise amplifier 2, a first attenuator 3, a first mixer 4, a low-pass filtering module 5, a second mixer 6, a processing module 7, a first local oscillator generator 8, a second local oscillator generator 9, a high-pass filtering module 10, a second attenuator 11, a power amplifier 12 and a signal transmitting module 14.

[0051] The signal receiving module 1, the low noise amplifier 2, the first attenuator 3, the first mixer 4, the low pass filter module 5, the second mixer 6, the high pass filter module 10, the second attenuator 11, the power amplifier 12 and the signal transmitting module 14 are connected in series in sequence; the first mixer 4 is connected to the first local oscillator generator 8, and the second mixer 6 is connected to the second local oscillator generator 9; the processing module 7 is respectively connected to the first local oscillator generator 8 and the second local oscillator generator 9;

[0052] The signal receiving module 1 receives the electromagnetic wave signal sent by the radar sensor, and then amplifies the electromagnetic wave signal and adjusts the electromagnetic wave amplitude through the low noise amplifier 2 and the first attenuator 3 in turn; the processing module 7 sets the preset parameters of the first local oscillator generator 8 based on the corresponding set simulation target parameters, and the first local oscillator generator 8 outputs the corresponding signal based on the preset parameters, and the signal output by the first local oscillator generator 8 and the signal output by the first attenuator 3 are converted into intermediate frequency signals through the first mixer 4, and the high-frequency signal part of the signal output by the first mixer 4 is filtered out through the low-pass filtering module 5 and the low-frequency signal part is retained; the processing module 7 is based on the corresponding set simulation target The preset parameters of the second local oscillator generator 9 are set according to the target parameters. The second local oscillator generator 9 outputs a corresponding signal based on the preset parameters. The signal output by the second local oscillator generator 9 is mixed with the signal output by the low-pass filter module 5 by the second mixer 6. The frequency of the second local oscillator generator 9 and the frequency of the first local oscillator generator 8 have a certain frequency difference according to the preset simulation target parameters. The low-frequency signal part of the signal output by the second mixer 6 is filtered out and the high-frequency signal part is retained. The signal is then amplified and the electromagnetic wave amplitude is adjusted by the second attenuator 11 in sequence. The signal transmitting module 14 returns the simulated target signal that meets the simulated target to the radar sensor.

[0053] In one embodiment, the radar target simulator is used to simulate the target speed and target amplitude of the Doppler radar detection target, so as to return the simulated target signal that meets the requirements of the Doppler radar detection target to the corresponding Doppler radar sensor.

[0054] In a specific embodiment, the method of simulating the target speed of the target detected by the Doppler radar includes:

[0055] The first local oscillator generator 8 changes the preset parameters of the first local oscillator generator 8 according to the digital signal generated by the processing module 7 based on the first analog target parameter related to the target speed of the Doppler radar detection target, and then the signal output by the first local oscillator generator 8 and the signal output by the first attenuator 3 are frequency-converted to intermediate frequency signals by the first mixer 4, and the high-frequency signal part of the signal output by the first mixer 4 is filtered out through the low-pass filter module 5 and the low-frequency signal part is retained, and then the second local oscillator generator 9 changes the preset parameters of the second local oscillator generator 9 according to the digital signal generated by the processing module 7 based on the second analog target parameter related to the target speed of the Doppler radar detection target. The signal of the corresponding frequency is mixed with the signal output by the low-pass filter module 5 by the second mixer 6, and the low-frequency signal part of the signal output by the second mixer 6 is filtered out through the high-pass filter module 10, and the high-frequency signal part is retained, and then the signal is amplified and the electromagnetic wave amplitude is adjusted through the second attenuator 11 and the power amplifier 12 in sequence to generate an analog target signal that meets the target speed of the Doppler radar detection target;

[0056] Among them, by setting the first simulated target parameter and the second simulated target parameter and changing the frequency of the output signal of the first local oscillator generator 8 and the second local oscillator generator 9 to generate a simulated target signal that meets the target speed of the Doppler radar detection target, the Doppler signal corresponding to different speeds of the detection target and the moving direction of the detection target relative to the radar can be simulated.

[0057] The principle of further simulating the target velocity of the Doppler radar detection target is:

[0058] The RF frequency emitted by the radar is f0, and the wavelength λ0 = c / f0, where c is the propagation speed of electromagnetic waves in a vacuum. The distance between the target and the radar is R. The total number of wavelengths of the signal emitted by the radar to the target and then returned to the radar by the target is 2R / λ0, that is, the total phase When the target moves, the moving target speed is v t , the phase φ changes with the distance R, producing the Doppler effect, and the corresponding Doppler frequency is f d , angular velocity at the same time

[0059]

[0060] but

[0061]

[0062] The Doppler radar target simulator in this scheme receives the RF signal sent by the radar as a sine wave RF in . The phase and gain amplitude changes in signal transmission are not considered, and do not affect the core content of the solution. in It can be simplified to define as cos(ω r t), the output frequency of the first local oscillator generator 8 is simplified to cos(ω1t), and the output frequency of the second local oscillator generator 9 is simplified to cos(ω2t). r t) After gain control by the low noise amplifier 2 and the first attenuator 3, the mixed signal of cos(ω1t) is down-converted by the first mixer 4:

[0063]

[0064] After passing through the low-pass filter module 5, the high-frequency signal is attenuated and filtered out, and the intermediate frequency signal is:

[0065]

[0066] The intermediate frequency signal and cos(ω2t) are up-converted by the second mixer 6 to form a mixed signal:

[0067]

[0068] After passing through the high-pass filter module 10, the low-frequency signal is attenuated and filtered out, and the output signal is:

[0069]

[0070] After that, the signal passes through the second attenuator 11 and the power amplifier 12 for gain control, and then the Doppler radar target simulator outputs a signal RF out The frequency is:

[0071]

[0072] It can be seen that the input radar signal RF of the Doppler radar target simulator in The frequency is ω r / 2π, output signal RF out The frequency is (ω r -ω1+ω2) / 2π, Doppler radar target simulator output signal RF out Compared to the input signal RF inThe frequency offset is (-ω1+ω2) / 2π, that is, the Doppler signal frequency corresponding to the simulated target movement is (-ω1+ω2) / 2π.

[0073] By setting the preset parameters of the first local oscillator generator 8 and the second local oscillator generator 9 by controlling the processing module 7 and adjusting the frequencies of cos(ω1t) and cos(ω2t), the Doppler signals corresponding to different speeds of the detection target and the moving direction of the detection target relative to the radar can be simulated. When (-ω1+ω2) / 2π>0, the simulated scenario is the Doppler frequency shift frequency corresponding to the speed of the detection target when it approaches the radar. When (-ω1+ω2) / 2π<0, the simulated scenario is the Doppler frequency shift frequency corresponding to the speed of the detection target when it moves away from the radar.

[0074] In a specific embodiment, RCS (Radar Cross Section) is a hypothetical area, which is defined as the ratio of the reverse echo power to the incident injection power density of a radar detection target in a given direction, and the parameter is described per unit area. The larger the RCS value, the stronger the backscatter echo capability, and the greater the echo power received by the radar.

[0075] The methods for simulating the target amplitude of Doppler radar detection targets include:

[0076] The signal amplitude is adjusted by setting one or more of the parameters of the low noise amplifier 2, the first attenuator 3, the second attenuator 11, and the power amplifier 12 to generate an analog target signal with an output power that meets the target amplitude.

[0077] Among them, the output power of the radar target simulator can be controlled by adjusting the parameters of the low-noise amplifier 2, the first attenuator 3, the second attenuator 11, the power amplifier 12 and other aspects, so as to achieve the purpose of simulating the target amplitude (RCS) of the Doppler radar detection target, and can flexibly meet the use scenarios of various input power and different output power target simulations.

[0078] In addition, the radar target simulator of the present invention can be applied to the target simulation of a frequency modulated continuous wave radar. The following introduces the simulation method of the frequency modulated continuous wave radar detecting the target by the present solution.

[0079] The frequency transmitted by Doppler radar is fixed, while the frequency transmitted by FMCW radar varies linearly with time, such as Figure 2 The figure shows the relationship between the transmission frequency of the FMCW radar and time; B is the FM bandwidth range, T is the FM period, a FM period is generally also called a chirp, and fc is the starting frequency of the transmitting signal.

[0080] like Figure 3A schematic structural diagram of a radar target simulator based on a mixing method in an embodiment of the present invention is shown.

[0081] The radar target simulator based on the frequency mixing method is used to simulate the detection target of the frequency modulated continuous wave radar.

[0082] The radar target simulator based on the mixing method includes: a signal receiving module 1 integrated on the simulator circuit board, a low-noise amplifier 2, a first attenuator 3, a first mixer 4, a low-pass filtering module 5, a second mixer 6, a processing module 7, a first local oscillator generator 8, a second local oscillator generator 9, a high-pass filtering module 10, a second attenuator 11, a power amplifier 12, a phase control circuit 13 and a signal transmitting module 14.

[0083] The signal receiving module 1, the low noise amplifier 2, the first attenuator 3, the first mixer 4, the low pass filter module 5, the second mixer 6, the high pass filter module 10, the second attenuator 11, the power amplifier 12, the phase control circuit 13 and the signal transmitting module 14 are connected in series in sequence; the first mixer 4 is connected to the first local oscillator generator 8, and the second mixer 6 is connected to the second local oscillator generator 9; the processing module 7 is respectively connected to the first local oscillator generator 8 and the second local oscillator generator 9;

[0084] The signal receiving module 1 receives the electromagnetic wave signal sent by the radar sensor, and then amplifies the electromagnetic wave signal and adjusts the electromagnetic wave amplitude through the low noise amplifier 2 and the first attenuator 3 in turn; the processing module 7 sets the preset parameters of the first local oscillator generator 8 based on the corresponding set simulation target parameters, and the first local oscillator generator 8 outputs the corresponding signal based on the preset parameters, and the signal output by the first local oscillator generator 8 and the signal output by the first attenuator 3 are converted into intermediate frequency signals through the first mixer 4, and the high-frequency signal part of the signal output by the first mixer 4 is filtered out through the low-pass filtering module 5 and the low-frequency signal part is retained; the processing module 7 sets the second local oscillator generator 9 based on the corresponding set simulation target parameters. Preset parameters, the second local oscillator generator 9 outputs a corresponding signal based on the preset parameters, and the signal output by the second local oscillator generator 9 is frequency-converted and mixed with the signal output by the low-pass filter module 5 through the second mixer 6. The frequency of the second local oscillator generator 9 and the frequency of the first local oscillator generator 8 have a certain frequency difference according to the preset simulated target parameters, and then the low-frequency signal part of the signal output by the second mixer 6 is filtered out by the high-pass filter module 10 and the high-frequency signal part is retained, and then the signal is amplified and the electromagnetic wave amplitude is adjusted by the second attenuator 11 and the power amplifier 12 in turn, and then the output signal phase is adjusted by the phase control circuit 13, and the signal transmission module 14 returns the simulated target signal that meets the simulated target to the radar sensor.

[0085] In one embodiment, the radar target simulator is used to simulate the detection target distance, target speed and target amplitude of the FMCW radar detection target, so as to return the simulated target signal that meets the FMCW radar detection target to the corresponding FMCW radar sensor.

[0086] In a specific embodiment, the method of simulating the detection target distance of the frequency modulated continuous wave radar detection target includes:

[0087] The first local oscillator generator 8 is used to change the preset parameters of the first local oscillator generator 8 according to the digital signal generated by the processing module 7 based on the third analog target parameter related to the detection target distance of the frequency modulated continuous wave radar detection target, and then the signal output by the first local oscillator generator 8 and the signal output by the first attenuator 3 are frequency-converted to intermediate frequency signals through the first mixer 4, and the high-frequency signal part of the signal output by the first mixer 4 is filtered out and the low-frequency signal part is retained, and then the first local oscillator generator 8 is converted into an intermediate frequency signal through the second mixer 6 according to the digital signal generated by the processing module 7 based on the third analog target parameter related to the detection target distance of the frequency modulated continuous wave radar detection target. The module 7 generates a digital signal based on a fourth analog target parameter related to the detection target distance of the frequency modulated continuous wave detection target, changes the preset parameter of the second local oscillator generator 9 to output a signal of a corresponding frequency, and performs frequency conversion mixing with the signal output by the low-pass filter module 5, and then filters out the low-frequency signal part of the signal output by the second mixer through the high-pass filter module 10 and retains the high-frequency signal part, and then sequentially passes through the second attenuator 11 and the power amplifier 12 to amplify the signal and adjust the electromagnetic wave amplitude, and adjusts the output signal phase through the phase control circuit 13 to generate an analog target signal that meets the detection target distance of the frequency modulated continuous wave radar detection target;

[0088] Among them, the frequencies of the output signals of the first local oscillator generator 8 and the second local oscillator generator 9 are changed by setting the third simulated target parameter and the fourth simulated target parameter to generate a simulated target signal with an intermediate frequency beat signal frequency that meets the target distance detection requirement of the frequency modulated continuous wave radar.

[0089] That is, in this embodiment, by changing the frequency parameters of the first local oscillator generator 8 and the second local oscillator generator 9, the first local oscillator generator 8 and the second local oscillator generator 9 output signals with a frequency that matches the detection target distance, and then obtain an analog target signal with an intermediate frequency beat signal frequency that matches the detection target distance, so that the frequency modulated continuous wave radar sensor can obtain the corresponding detection target distance.

[0090] Furthermore, the principle of simulating the detection target distance of the FMCW radar is as follows:

[0091] like Figure 4 As shown in the figure, the signal emitted by the FMCW radar will be reflected back after encountering the detection target and will be amplified and received by the radar. From the frequency and time relationship diagram, the waveforms of the transmitted signal and the received signal are exactly the same, except for a delay τ. This delay τ is the time it takes for the electromagnetic wave to be emitted by the radar, reach the detection target, and then be reflected back to the radar by the detection target.

[0092] Right now

[0093]

[0094] Among them, R is the distance between the FMCW radar and the detection target, and c is the propagation speed of electromagnetic waves in a vacuum. It can be seen that knowing the delay τ can calculate the detection target distance R according to the above formula.

[0095] like Figure 5 As shown in the figure, after the FMCW radar receives and transmits the signal, two frequency signals, fb and B-fb, are obtained. Generally, B is much larger than fb. A low-pass filter is used to filter out the B-fb signal, leaving only the fb signal. The delay τ is then obtained using the proportional relationship, that is,

[0096]

[0097] Wherein, T is the frequency modulation period of the FMCW radar, B is the frequency modulation bandwidth of the FMCW radar, and fb is the intermediate frequency beat signal frequency.

[0098] Combining formula (8) and formula (9), the relationship between the FMCW radar and the target detection distance R and the intermediate frequency beat signal frequency fb can be calculated:

[0099]

[0100] Wherein, T is the frequency modulation period of the FMCW radar, c is the propagation speed of electromagnetic waves in vacuum, B is the frequency modulation bandwidth of the FMCW radar, and fb is the frequency of the intermediate frequency beat signal of the FMCW radar.

[0101] The frequency of the FMCW radar is modulated over time, but at a certain point in time, the frequency is fixed. The radar signal at this point in time is input into the target simulator RF in It can be simplified to be defined as For the sake of simplicity, the phase shift, delay and gain change in the air and circuit transmission process are not considered, which does not affect the core content of the solution. The output frequency of the first local oscillator generator 8 is simplified as: The output frequency of the second local oscillator generator 9 is simplified as After gain control by the low noise amplifier 2 and the first attenuator 3, the first local oscillator generator 8 outputs the signal The mixed signal after down-conversion by the first mixer 4 is:

[0102]

[0103] After passing through the low-pass filter module 5, the high-frequency signal is attenuated and filtered out, and the intermediate frequency signal is:

[0104]

[0105] The intermediate frequency signal and the output signal of the second local oscillator generator 9 The mixed signal after up-conversion by the second mixer 6 is:

[0106]

[0107] After passing through the high-pass filter module 10, the low-frequency signal is attenuated and filtered out, and the output signal is:

[0108]

[0109] After that, the signal passes through the second attenuator 11 and the power amplifier 12 for gain control, and then passes through the phase control circuit 13. The phase shift of the phase control circuit 13 is The output signal RF of the FMCW radar target simulator is out for:

[0110]

[0111] like Figure 6 As shown in the figure, the radar signal RF input by the FMCW radar target simulator at a certain point in time in The frequency is ω r / 2π, output signal RF out The frequency is (ω r -ω1+ω2) / 2π, frequency modulated continuous wave radar target simulator output signal RF out Compared to the input signal RF in The frequency offset is (-ω1+ω2) / 2π. Similarly, at other time points, the input signal frequency of the FMCW radar target simulator is different, but the frequency offset of the output signal compared to the input signal is also (-ω1+ω2) / 2π, that is, the frequency fb of the simulated FMCW radar intermediate frequency beat signal is (ω1-ω2) / 2π. (Generally ω1>ω2).

[0112] By controlling the microprocessor to set the first local oscillator generator 8 and the second local oscillator generator 9 and adjusting the frequencies of cos(ω1t) and cos(ω2t), target simulation signals with different beat frequencies fb can be simulated. That is, by modifying the parameters ω1 and ω2, the echo signals of the target detected by the frequency modulated continuous wave radar at different distances can be simulated, and the corresponding simulated distance information can be calculated by formula (10).

[0113] In one embodiment, the method of simulating the target speed of the target detected by the FMCW radar includes:

[0114] The first local oscillator generator 8 changes the preset parameters of the first local oscillator generator 8 to output a signal of a corresponding phase according to the digital signal generated by the processing module 7 based on the fifth analog target parameter related to the detection target speed of the frequency modulated continuous wave radar detection target, and then the signal output by the first local oscillator generator 8 and the signal output by the first attenuator 3 are frequency-converted to an intermediate frequency signal through the first mixer 4, and the high-frequency signal part of the signal output by the first mixer 4 is filtered out and the low-frequency signal part is retained through the low-pass filtering module 5, and then the first local oscillator generator 8 is converted to an intermediate frequency signal through the second mixer 6 according to the digital signal generated by the processing module 7 based on the fifth analog target parameter related to the detection target speed of the frequency modulated continuous wave radar detection target. The processing module 7 changes the signal of the corresponding phase output by the preset parameter of the second local oscillator generator 9 based on the digital signal generated by the sixth analog target parameter related to the target speed of the frequency modulated continuous wave detection target, and performs frequency conversion mixing with the signal output by the low-pass filter module 5, and then filters out the low-frequency signal part of the signal output by the second mixer 6 through the high-pass filter module 10 and retains the high-frequency signal part, and then sequentially passes through the second attenuator 11 and the power amplifier 12 to amplify the signal and adjust the electromagnetic wave amplitude, and adjusts the output signal phase through the phase control circuit 13 to generate an analog target signal that meets the target speed of the frequency modulated continuous wave radar detection target;

[0115] Among them, the phases of the output signals of the first local oscillator generator 8 and the second local oscillator generator 9 are changed by setting the fifth analog target parameter and the sixth analog target parameter, and then the phase parameters of the phase control circuit 13 are set to generate an analog target signal corresponding to the phase of the intermediate frequency beat signal that meets the target speed, so as to generate an analog target signal that meets the target speed of the frequency modulated continuous wave radar detection target.

[0116] That is, this embodiment obtains an analog target signal with an intermediate frequency beat signal phase that meets the target detection distance by changing the phase parameters of the first local oscillator generator 8, the second local oscillator generator 9 and the phase control circuit 13, so that the FMCW radar sensor can obtain the corresponding target speed.

[0117] Furthermore, the principle of simulating the target speed of the FMCW radar detection target is as follows:

[0118] The principle of FMCW radar detecting target speed. Due to the change in detection distance caused by the movement of the detected target, the beat frequency fb detected between the chirps of the FMCW radar will show a certain frequency shift change trend. Generally, since the time between chirps is very short, the distance change caused by the movement is very small, and the change in fb frequency is very small and cannot be distinguished, but the phase change of fb is very obvious.

[0119] Define the target motion speed as v, the chirp modulation period as T, then the distance between two chirps is Δd:

[0120] Δd=v·T; (16)

[0121] Define the phase change of the beat frequency fb between two chirps as According to the relationship between phase change and wavelength,

[0122]

[0123] Among them, λ=c / fc, c is the propagation speed of light in vacuum, and fc is the starting frequency of FMCW radar transmission.

[0124] From formulas (16) and (17), we can get v and The relationship is

[0125]

[0126] According to formula (18), different It can simulate and detect different speed information v of the target. Indicates that the detected target is moving away from the radar direction. Indicates that the detected target is moving towards the radar direction.

[0127] According to formula (15), The detection target simulation signal corresponding to the signal is

[0128]

[0129] Echo analog signal The frequency modulated continuous wave radar amplifies the received signal and the local oscillator signal After mixing, the intermediate frequency beat frequency fb is obtained, then

[0130]

[0131]

[0132] The high frequency component is filtered out by the intermediate frequency low-pass filter module.

[0133]

[0134] According to formula (21), the phase of the intermediate frequency beat frequency fb corresponding to the echo signal generated by the simulator received by the FMCW radar is Only the phase of the output signal of the first local oscillator generator 8 The second local oscillator generator 9 outputs a signal phase Phase control circuit 13 phase Correlation, and phase of FMCW radar signal Not relevant. Then by controlling One or more values ​​make the phase difference of the chirp beat frequency fb By satisfying formula (18), the velocity information v corresponding to the detected target can be simulated.

[0135] In one embodiment, the method of simulating the target amplitude of the frequency modulated continuous wave radar detection target includes: adjusting the signal amplitude by setting one or more of the parameters of the low noise amplifier 2, the first attenuator 3, the second attenuator 11, and the power amplifier 12 to generate a simulated target signal with an output power that meets the target amplitude.

[0136] Among them, the output power of the radar target simulator can be controlled by adjusting the parameters of the low noise amplifier 2, the first attenuator 3, the second attenuator 11, the power amplifier 12 and other aspects, so as to achieve the purpose of simulating the target amplitude (RCS) of the frequency modulated continuous wave radar detection target, and can flexibly meet the use scenarios of various input power and different output power target simulations.

[0137] In one embodiment, if Figure 7 As shown in FIG8 , 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 present application can select the built-in circularly polarized receiving antenna 101 or the receiving radio frequency head 103 plus an external receiving antenna through the first radio frequency switch 102 to receive the electromagnetic wave signal emitted by the radar;

[0138] Wherein, the built-in circularly polarized receiving antenna 101 is used to receive electromagnetic wave signals in orthogonal directions;

[0139] The receiving radio frequency head 103 is used to connect an external receiving antenna to receive electromagnetic wave signals through the receiving antenna; the receiving antenna is set according to requirements.

[0140] The first RF switch 102 is connected to the built-in circularly polarized receiving antenna 101 and the receiving RF head 103, and is used to control the built-in circularly polarized receiving antenna 101 or the receiving antenna externally connected to the receiving RF head 103 to receive the corresponding electromagnetic wave signal, so as to input the electromagnetic wave signal into the low noise amplifier 2.

[0141] In one embodiment, if Figure 7 As shown in FIG8 , the signal transmitting module 14 includes: a built-in circularly polarized transmitting antenna 141, a second RF switch 142, and a transmitting RF head 143; the present application can select the built-in circularly polarized transmitting antenna 141 or the transmitting RF head 143 plus an external transmitting antenna through the second RF switch 142 to transmit the simulated target signal to the radar sensor;

[0142] Wherein, the built-in circularly polarized transmitting antenna 141 is used to transmit the simulated target signal in the form of circularly polarized electromagnetic waves;

[0143] The transmitting radio frequency head 143 is used to be connected to an external transmitting antenna so as to transmit the simulated target signal through the transmitting antenna; the transmitting antenna is set according to requirements.

[0144] The RF switch 142 is connected to the built-in circularly polarized transmitting antenna 141 and the transmitting RF head 143 , and is used to control the transmission of the analog target signal by the built-in circularly polarized transmitting antenna 141 or the transmitting antenna externally connected to the transmitting RF head 143 .

[0145] In one embodiment, in order to prevent the problem of large differences in analog signal amplitudes due to different polarization directions of radar product antennas, and at the same time reduce the problem of large differences in polarization deflection signals between individuals caused by differences in the spatial placement of the products under test when measuring multiple radar products under test.

[0146] A built-in circularly polarized receiving antenna and a built-in circularly polarized transmitting antenna are used for signal reception and signal transmission.

[0147] The built-in circularly polarized receiving antenna and the built-in circularly polarized transmitting antenna are respectively embedded in the front side (antenna side) of the simulator circuit board, and feeding networks matched with the built-in circularly polarized receiving antenna and the built-in circularly polarized transmitting antenna are respectively arranged on the back side (feeding network side) of the simulator circuit board; the built-in circularly polarized receiving antenna and the built-in circularly polarized 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 antenna to the corresponding feeding network in the form of a metal via; wherein the distances from the first feeding point and the second feeding point to the geometric center of the corresponding antenna are equal, and the lines connecting the two feeding points to the geometric center are orthogonal to each other;

[0148] The built-in circularly polarized receiving antenna is combined with a corresponding feeding network to obtain the received electromagnetic wave signal sent by the radar sensor; the built-in circularly polarized transmitting antenna is combined with a corresponding feeding network to send the generated simulated target signal to the radar sensor in the form of a circularly polarized electromagnetic wave.

[0149] Each feeding network is provided with a power divider and a resistor; wherein one end of the power divider is connected to the first feeding point and the second feeding point of the corresponding antenna, and the other end is connected to the low noise amplifier 2 or the power amplifier 12 or the phase control circuit 13 arranged on the simulator circuit board; the resistor bridges the first feeding point and the second feeding point to the first specific position and the second specific position respectively arranged on the transmission section of the power divider, and the resistance value is twice the impedance value of the transmission microstrip line.

[0150] If the feeding network is set corresponding to the built-in circular polarization receiving antenna, one end is connected to the first feeding point and the second feeding point of the built-in circular polarization receiving antenna; the other end passes through a power divider and is connected to the low noise amplifier 2 after combining. If the feeding network is set corresponding to the built-in circular polarization transmitting antenna, one end is connected to the first feeding point and the second feeding point of the built-in circular polarization transmitting antenna; the other end passes through a power divider and is connected to the power amplifier 12 or the phase control circuit 13 after combining; preferably, the power divider is a one-to-two equal power divider.

[0151] Preferably, the length of each transmission line of the feeding network has special requirements. In order to synthesize accurate circularly polarized electromagnetic waves, the length L of the transmission line between the first specific position A and the first feeding point 1 is A1 , and the transmission section length L between the second specific position B and the second feeding point 2 B2 and the first specific position A to the power divider D satisfy the first length relationship; and the corresponding transmission segment length L between the first specific position A and the power divider D DA and the transmission segment length L corresponding to the second specific position B to the power divider D DB The second length relationship is satisfied to ensure that the phase difference between the two feeding points is exactly 90°, and the power is equal, so as to synthesize an accurate circularly polarized electromagnetic wave. The transmission segment length L corresponding to the first specific position A through the resistor R to the second specific position B ARB and the transmission segment length L corresponding to the first specific position A through the power divider D to the second specific position B ADB The third length relationship is satisfied.

[0152] Wherein, the first length relationship includes:

[0153]

[0154] And among them, λ is the wavelength of electromagnetic wave in air at the radar operating frequency, ε is the dielectric constant of the circuit board, and N is a natural number.

[0155] Furthermore, the second length relationship corresponds to the transmission segment length L between the first specific position A and the power divider D. DA and the transmission segment length L corresponding to the second specific position B to the power divider D DB equal.

[0156] At this time, the phase difference between the two feeding points is 90°, the power is equal, and the electromagnetic waves excited respectively are a pair of linearly polarized waves orthogonal to each other. The synthesized waveform is a circularly polarized wave.

[0157] The third length relationship includes:

[0158]

[0159] And among them, L ARB is the length of the transmission segment from the first specific position A through the resistor R to the second specific position B, L ADB is the length of the transmission segment from the first specific position A through the power divider D to the second specific position B, λ is the wavelength of the electromagnetic wave in the air at the radar operating frequency, ε is the dielectric constant of the circuit board, and N is a natural number.

[0160] In one embodiment, the feeding circuit may also adopt solutions such as a bridge and a Barenga phase shifter; the implementation of the built-in circularly polarized receiving and transmitting antenna may also adopt other solutions such as antenna cutting and slotting.

[0161] In one embodiment, the radar target simulator based on the mixing mode is connected to a host computer control terminal; further, Figure 1 As shown in FIG. 3 , the processing module 7 is connected to the host computer control terminal 15 , and is used to set the simulation target parameters based on the control instructions of the host computer control terminal 15 , and generate a digital signal that meets the characteristics of the simulation target.

[0162] Preferably, the radar target simulator based on the mixing mode is connected to the host computer control terminal 15 through a USB interface, and the host computer control terminal 15 identifies the serial port of the radar target simulator based on the mixing mode through the connected USB interface, and can modify the internal parameters of the processing module 7 through the serial port to adjust the simulated target characteristics, and the parameter modification takes effect in real time and can be saved by power failure as needed. If the simulated target parameters do not need to be modified for the next use, the host computer can be used to modify the target parameters. In the process of implementing this solution, low-power design is taken into consideration, and the host computer control terminal USB can be used for power supply, without the need to increase the cost of DC power supply.

[0163] A microwave radar sensor testing system is provided in an embodiment of the present invention.

[0164] The system comprises: radar sensors, each mounted on a tooling plane of a fixed tooling;

[0165] A radar target simulator is installed in a normal direction along the tooling plane;

[0166] The radar target simulator simulates the detection target based on the received electromagnetic wave signal emitted by the radar sensor and the simulated target parameters related to the detection target, and returns each simulated target signal that meets the detection target to the corresponding radar sensor.

[0167] In order to better describe the microwave radar sensor test system, it is now explained in conjunction with the following specific embodiments.

[0168] For microwave radar sensor test systems for Doppler radar, such as Fig. 9 A schematic diagram of an application test environment of a microwave radar sensor test system for Doppler radar in an embodiment of the present invention is shown.

[0169] The radar target simulator based on the mixing method can be applied to the target simulation of a single radar sensor product, such as the test and analysis of the signal processing capability of the radar sensor product during the research and development process; it can also be applied to the target simulation of multiple radar sensor products at the same time, such as the production test of multiple radar sensor products;

[0170] The system is in an external environment built with absorbing materials, including:

[0171] One or more Doppler radar sensors 91 mounted on a fixture plane of the fixed fixture 01;

[0172] A radar target simulator 92 based on a mixing method is installed in the normal direction along the tooling plane as a target simulator of the test system; it should be noted that the radar target simulator 92 based on the mixing method can be implemented as follows: Figure 1 And all functions of the radar target simulator based on the mixing mode of 7 are not described in detail. In addition, the radar target simulator based on the mixing mode 92 is also connected to the host computer control terminal through a USB interface using a USB power supply serial communication line.

[0173] It should be noted that the tooling design for testing the Doppler radar sensor 91 is, in most cases, spread out along a plane, and the target simulator is placed in the normal direction of the plane, so that the difference in the target detection simulation results is small. However, the spread of the Doppler radar sensor 91 is not limited to equidistant spread. In theory, the Doppler radar sensors 91 can be separated by a certain distance from each other, and there is no requirement for the regularity of the orientation and arrangement.

[0174] Among them, the radar target simulator 92 based on the mixing method simulates the target speed and target amplitude of the simulated target in turn based on the received electromagnetic waves emitted by each Doppler radar sensor 91 and the simulated target parameters related to the simulated target, and returns each simulated target signal that meets the target speed and target amplitude of the simulated target to the corresponding Doppler radar sensor 91.

[0175] Because the installation position of the Doppler radar sensor is offset significantly relative to the target simulator, signal transmission and reception are no longer strictly transmitted in the normal direction, so there is polarization deflection. This scheme adopts a radar target simulator 92 based on the mixing method. For Doppler radar sensors with arbitrarily deflected circular polarization signals can be transmitted and received by reducing the power by half, so that the radar target simulator 92 based on the mixing method corresponds to multiple Doppler radar sensors, and can transmit and receive signals with the same amplitude.

[0176] In one embodiment, if Fig. 9 As shown, the radar target simulator 91 based on the mixing method is installed in the normal direction along the tooling plane, and the distance from the tooling plane is d. Then d satisfies the fixed distance relationship;

[0177] Wherein, the fixed distance relationship includes:

[0178]

[0179] And wherein, D is the diagonal length of the Doppler radar sensor fixing fixture, and λ is the wavelength in the air corresponding to the electromagnetic wave at the radar operating frequency.

[0180] In a specific embodiment, 9 Doppler radar sensors and a radar target simulator based on a mixing method are used for testing. The 9 Doppler radar sensors are installed on a fixed tooling, such as Fig.10 As shown, it is spread out in a nine-square grid plane; the target simulator adopts a radar target simulator based on a mixing method, which is installed in the normal direction along the tooling plane, and the distance from the tooling is d, and the value of d satisfies the corresponding formula (24);

[0181] According to the principle of circularly polarized antenna, circularly polarized signals can be equivalently decomposed into any two orthogonal polarization signals with equal amplitude and 90° phase difference. Therefore, no matter how the polarization direction of the microwave radar sensor antenna under test is placed, the circularly polarized antenna used by the radar target simulator can always be decomposed into a signal with one polarization direction consistent with the polarization direction of the microwave radar sensor antenna, and another signal orthogonal to the polarization direction of the microwave radar sensor antenna. Therefore, no matter what the polarization direction of the microwave radar sensor antenna is, the radar target simulator of this solution can always send and receive microwave signals with equal amplitudes to the microwave radar sensor under test, and the test results will not be interfered by the inconsistency between the polarization direction of the microwave radar sensor antenna and the polarization direction of the circularly polarized antenna test equipment antenna.

[0182] Moreover, in the general circular polarization design, after the circular polarization is decomposed into two orthogonal linear polarizations, the ratio of the amplitudes of the two linear polarizations is called the axial ratio. Generally, when the axial ratio is ≤3dB, it is considered to meet the circular polarization design requirements. Fig.11 The axial ratio index of the target simulator of this scheme at each main direction angle. It can be seen that the axial ratio index of this scheme is basically maintained below 1dB, and the strictness of circular polarization is higher than the general standard.

[0183] For microwave radar sensor test systems for FMCW radars, such as Fig.12 A schematic diagram of an application test environment of a microwave radar sensor test system for a frequency modulated continuous wave radar in an embodiment of the present invention is shown.

[0184] The FMCW radar target simulator is used for target simulation of a single radar sensor product, such as the signal processing capability test and analysis of radar sensor products during the R&D process;

[0185] The system is in an external environment built with absorbing materials, including:

[0186] A frequency modulated continuous wave radar sensor 121 installed on a tooling plane of the fixed tooling 01;

[0187] A frequency modulated continuous wave radar target simulator 122 using a radar target simulator based on a mixing method is installed in the normal direction along the tooling plane, as a target simulator of the test system, that is, a frequency modulated continuous wave radar target simulator; it should be noted that the target simulator 122 can implement the above embodiment Figure 2 as well as Figure 8 All functions of the radar target simulator based on the mixing mode are not described in detail. In addition, the radar target simulator 122 is also connected to the host computer control terminal through a USB interface using a USB power supply serial communication line.

[0188] It should be noted that if Fig.13 As shown, the tooling design for testing the FMCW radar sensor 121 is, in most cases, placed along a plane, and the target simulator is placed in the normal direction of the plane, so that the difference in the simulation results of detecting the target is small.

[0189] Among them, the radar target simulator 122 simulates the detection target distance, target speed and target amplitude of the detection target based on the received electromagnetic waves emitted by the frequency modulated continuous wave radar sensor 121 and the simulated target parameters related to the detection target, and returns the simulated target signal that conforms to the detection target distance, target speed and target amplitude of the detection target to the corresponding radar sensor, so that the radar sensor can obtain the detection target distance, target speed and target amplitude of the detection target based on the received simulated target signal.

[0190] In one embodiment, if Fig.12 As shown, the radar target simulator 122 is installed in the normal direction along the tooling plane, and the distance from the tooling plane is d. Then d satisfies the fixed distance relationship;

[0191] Wherein, the fixed distance relationship includes:

[0192]

[0193] And wherein, D is the diagonal length of the FMCW radar sensor fixing fixture, and λ is the wavelength in the air corresponding to the electromagnetic wave at the radar operating frequency.

[0194] Moreover, in the general circular polarization design, after the circular polarization is decomposed into two orthogonal linear polarizations, the ratio of the amplitudes of the two linear polarizations is called the axial ratio. Generally, when the axial ratio is ≤3dB, it is considered to meet the circular polarization design requirements. Fig.14 The axial ratio index of the target simulator of this scheme at each main direction angle. It can be seen that the axial ratio index of this scheme is basically maintained below 1dB, and the strictness of circular polarization is higher than the general standard.

[0195] Therefore, compared with the prior art, the present invention has the following advantages:

[0196] 1. Based on the technical solution of the present invention, the microwave radar test solution is more economical and flexible, the scene repeatability and controllability are better, and the qualitative measurement of the previous random target scene is transformed into the quantitative measurement of the target information fixed, which plays an important role in the research and development, problem analysis and production process of radar.

[0197] 2. Based on the design of the built-in circularly polarized antenna included in the technical solution of the present invention, the stringent requirements on the polarization direction of the radar product antenna are reduced during use, and the problem of large differences in simulated target performance caused by improper placement of the polarization direction of the radar product antenna is reduced. In the batch radar product testing scenario, the problem of large differences in simulated target performance caused by differences in the positions of batch radar products is also reduced, and the consistency of batch test results is improved.

[0198] 3. Based on the technical solution of the present invention, a highly integrated and miniaturized design is adopted, which is convenient for carrying and installation, and can be used without obstacles in a small environment. The corresponding shielding environment can be relatively small in size, saving shielding environment space and cost.

[0199] 4. Based on the technical solution of the present invention, taking into account the low power consumption design, the USB interface of the host computer can meet the power supply demand, and no additional DC power supply is required, which is convenient to use and saves the cost of purchasing DC power supply.

[0200] In summary, the radar target simulator based on the mixing mode and the microwave radar sensor test system of the present invention, after receiving the electromagnetic wave signal of the radar sensor, generates and returns an echo signal containing the detection target information to the radar sensor through the circuit of the radar target simulator based on the mixing mode, and deduces whether the function of the radar in the actual scene can meet the use requirements through the radar's processing ability of the echo signal. The target signal that is difficult to quantify, inflexible and has poor repeatability in the prior art is given, adjustable and repeatable, and the target feature information of the radar echo signal is accurately set, making the microwave radar test more economical and flexible, and the scene repeatability and controllability are better.

[0201] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A radar target simulator based on a mixing method, characterized in that: Used to simulate the detection target, the target simulator includes: A signal receiving module, a low noise amplifier, a first attenuator, a low pass filter module, a first mixer, a second mixer, a processing module, a first local oscillator generator, a second local oscillator generator, a high pass filter module, a second attenuator, a power amplifier and a signal transmitting module; The signal receiving module, the low noise amplifier, the first attenuator, the first mixer, the low pass filter module, the second mixer, the high pass filter module, the second attenuator, and the power amplifier are connected in series in sequence; the first mixer is connected to the first local oscillator generator, and the second mixer is connected to the second local oscillator generator; the processing module is connected to the first local oscillator generator and the second local oscillator generator respectively; The signal receiving module receives the electromagnetic wave signal sent by the radar sensor, and then the electromagnetic wave signal is amplified and the electromagnetic wave amplitude is adjusted through the low noise amplifier and the first attenuator in turn; the signal output by the first local oscillator generator whose preset parameters are set by the processing module based on the corresponding set simulated target parameters and the signal output by the first attenuator are frequency-converted to intermediate frequency signals through the first mixer, and the high-frequency signal part of the signal output by the first mixer is filtered out through the low-pass filter module and the low-frequency signal part is retained, and then the signal output by the second local oscillator generator whose preset parameters are set by the processing module based on the corresponding set simulated target parameters and the signal output by the low-pass filter module are frequency-converted and mixed through the second mixer, and the low-frequency signal part of the signal output by the second mixer is filtered out through the high-pass filter module and the high-frequency signal part is retained, and then the signal is amplified and the electromagnetic wave amplitude is adjusted through the second attenuator and the power amplifier in turn, and the simulated target signal that meets the simulated target is returned to the radar sensor by the signal transmitting module; The radar target simulator further comprises: a phase control circuit connected between the power amplifier and the signal transmission module; the radar target simulator is used to simulate the detection target distance, target speed and target amplitude of the frequency modulated continuous wave radar detection target, so as to return the simulated target signal that meets the frequency modulated continuous wave radar detection target to the corresponding frequency modulated continuous wave radar sensor; The frequencies of the output signals of the first local oscillator generator and the second local oscillator generator are changed by setting the third simulated target parameter and the fourth simulated target parameter to generate a simulated target signal of the intermediate frequency beat signal frequency that meets the target detection distance, so as to generate a simulated target signal of the target detection distance that meets the frequency modulated continuous wave radar target detection distance; The phases of the output signals of the first local oscillator generator and the second local oscillator generator are changed by setting the fifth simulated target parameter and the sixth simulated target parameter, and then the phase parameters of the phase control circuit are set to generate a simulated target signal corresponding to the phase of the intermediate frequency beat signal that meets the target speed, so as to generate a simulated target signal that meets the target speed detected by the frequency modulated continuous wave radar; The signal amplitude is adjusted by setting one or more of the parameters of the low noise amplifier, the first attenuator, the second attenuator, and the power amplifier to generate an analog target signal with an output power that meets the target amplitude.

2. The radar target simulator based on the mixing method according to claim 1, characterized in that: The radar target simulator is used to simulate the target speed and target amplitude of the Doppler radar detection target, so as to return the simulated target signal that meets the Doppler radar detection target to the corresponding Doppler radar sensor.

3. The radar target simulator based on the mixing method according to claim 2, characterized in that: The methods for simulating the target velocity of a Doppler radar detection target include: The first local oscillator generator is used to change the preset parameters of the first local oscillator generator according to the digital signal generated by the processing module based on the first analog target parameter related to the target speed of the Doppler radar detection target, and then the signal output by the first local oscillator generator and the signal output by the first attenuator are converted to intermediate frequency signals by the first mixer, and the high-frequency signal part of the signal output by the first mixer is filtered out through a low-pass filter module and the low-frequency signal part is retained, and then the first local oscillator generator is used to change the preset parameters of the second local oscillator generator according to the digital signal generated by the processing module based on the second analog target parameter related to the target speed of the Doppler radar detection target. The signal of the corresponding frequency is mixed with the signal output by the low-pass filter module by the second mixer, and then the low-frequency signal part of the signal output by the second mixer is filtered out through the high-pass filter module and the high-frequency signal part is retained, and then the signal is amplified and the electromagnetic wave amplitude is adjusted through the second attenuator and the power amplifier in sequence to generate an analog target signal that meets the target speed of the Doppler radar detection target; The first simulated target parameter and the second simulated target parameter are set to change the frequencies of the output signals of the first local oscillator generator and the second local oscillator generator to generate a simulated target signal that meets the target speed of the Doppler radar detection target.

4. The radar target simulator based on the mixing method according to claim 2, characterized in that: The target simulator simulates the target amplitude of the Doppler radar detection target in the following manner: The signal amplitude is adjusted by setting one or more of the parameters of the low noise amplifier, the first attenuator, the second attenuator, and the power amplifier to generate an analog target signal with an output power that meets the target amplitude.

5. The radar target simulator based on the mixing method according to claim 1, characterized in that: Methods for simulating the detection target distance of a frequency modulated continuous wave radar detection target include: The first local oscillator generator is used to change the preset parameters of the first local oscillator generator according to the digital signal generated by the processing module based on the third analog target parameter related to the detection target distance of the frequency modulated continuous wave radar, and then the signal output by the first local oscillator generator and the signal output by the first attenuator are converted to intermediate frequency signals by the first mixer, and the high-frequency signal part of the signal output by the first mixer is filtered out through a low-pass filter module and the low-frequency signal part is retained, and then the first local oscillator generator is used to change the preset parameters of the second local oscillator generator according to the digital signal generated by the processing module based on the fourth analog target parameter related to the detection target distance of the frequency modulated continuous wave radar. The signal of the corresponding frequency is mixed with the signal output by the low-pass filter module by the second mixer, and then the low-frequency signal part of the signal output by the second mixer is filtered out through the high-pass filter module and the high-frequency signal part is retained, and then the signal is amplified and the electromagnetic wave amplitude is adjusted by the second attenuator and the power amplifier in sequence, and the phase of the output signal is adjusted by the phase control circuit to generate an analog target signal that meets the detection target distance of the frequency modulated continuous wave radar; Among them, the frequencies of the output signals of the first local oscillator generator and the second local oscillator generator are changed by setting the third simulated target parameter and the fourth simulated target parameter to generate a simulated target signal with an intermediate frequency beat signal frequency that conforms to the detection target distance, so as to generate a simulated target signal with a detection target distance that conforms to the detection target of the frequency modulated continuous wave radar.

6. The radar target simulator based on the mixing method according to claim 1, characterized in that: Methods for simulating the target velocity of a target detected by a FMCW radar include: The first local oscillator generator changes the preset parameters of the first local oscillator generator according to the digital signal generated by the processing module based on the fifth analog target parameter related to the target speed of the frequency modulated continuous wave radar detection target, and then the signal output by the first local oscillator generator and the signal output by the first attenuator are frequency-converted to intermediate frequency signals by the first mixer, and the high-frequency signal part of the signal output by the first mixer is filtered out through a low-pass filter module and the low-frequency signal part is retained, and then the first local oscillator generator changes the preset parameters of the second local oscillator generator according to the digital signal generated by the processing module based on the sixth analog target parameter related to the target speed of the frequency modulated continuous wave detection target. The signal of the corresponding phase is mixed with the signal output by the low-pass filter module by the second mixer, and the low-frequency signal part of the signal output by the second mixer is filtered out through the high-pass filter module and the high-frequency signal part is retained, and then the signal is amplified and the electromagnetic wave amplitude is adjusted by the second attenuator and the power amplifier in sequence, and the phase of the output signal is adjusted by a phase control circuit corresponding to a phase parameter to generate an analog target signal that meets the target speed of the frequency modulated continuous wave radar detection target; Among them, the phases of the output signals of the first local oscillator generator and the second local oscillator generator are changed by setting the fifth simulated target parameter and the sixth simulated target parameter, and then the phase parameters of the phase control circuit are set to generate a simulated target signal corresponding to the phase of the intermediate frequency beat signal that meets the target speed, so as to generate a simulated target signal that meets the target speed detected by the frequency modulated continuous wave radar.

7. The radar target simulator based on the mixing method according to claim 1, characterized in that: Methods for simulating the target amplitude of a FMCW radar detection target include: The signal amplitude is adjusted by setting one or more of the parameters of the low noise amplifier, the first attenuator, the second attenuator, and the power amplifier to generate an analog target signal with an output power that meets the target amplitude.

8. The radar target simulator based on the mixing method according to claim 1, characterized in that: The signal receiving module comprises: a built-in circular polarization receiving antenna, a first radio frequency switch and a receiving radio frequency head; Wherein, the built-in circularly polarized receiving antenna is used to receive electromagnetic wave signals in orthogonal directions; The receiving radio frequency head is used to be externally connected to a receiving antenna so as to receive electromagnetic wave signals through the receiving antenna; The first RF switch is connected to the built-in circularly polarized receiving antenna and the receiving RF head, and is used to control the corresponding electromagnetic wave signal received by the built-in circularly polarized receiving antenna or the receiving antenna external to the receiving RF head, so as to input the electromagnetic wave signal into the low-noise amplifier.

9. The radar target simulator based on the mixing method according to claim 1, characterized in that: The signal transmission module includes: a built-in circular polarization transmitting antenna, a second radio frequency switch and a transmitting radio frequency head; Wherein, the built-in circularly polarized transmitting antenna is used to transmit a simulated target signal in the form of a circularly polarized electromagnetic wave; The transmitting radio frequency head is used to be connected to an external transmitting antenna so as to transmit the simulated target signal through the transmitting antenna; The second radio frequency switch is connected to the built-in circularly polarized transmitting antenna and the transmitting radio frequency head, and is used to control the transmission of the analog target signal by the built-in circularly polarized transmitting antenna or the transmitting antenna externally connected to the transmitting radio frequency head.

10. The radar target simulator based on the mixing method according to claim 1, characterized in that: The processing module is used to set the simulated target parameters based on the control instructions of the upper computer control terminal connected to the radar target simulator, and generate a digital signal that meets the characteristics of the simulated target.

11. A microwave radar sensor test system, characterized in that: The system comprises: The radar sensors are respectively installed on the tooling planes of the fixed tooling; The radar target simulator according to any one of claims 1 to 10, mounted in a normal direction along a tooling plane; The radar target simulator simulates the detection target based on the received electromagnetic wave signal emitted by the radar sensor and the simulated target parameters related to the detection target, and returns each simulated target signal that meets the detection target to the corresponding radar sensor.

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