Target distance and speed measurement method and device based on frequency-modulated continuous wave radar

Abstract

The application discloses a target distance and speed measuring method and device based on frequency modulation continuous wave radar, wherein the method comprises the following steps: mixing the chirp transmitting signal and the receiving signal in the first frame signal to obtain the intermediate frequency signal, and obtaining the spectrum peak frequency and the phase change; mixing the chirp transmitting signal and the receiving signal in the second frame signal to obtain the intermediate frequency signal, and obtaining the spectrum peak frequency and the phase change; using and to obtain the accurate measured target speed, and then obtaining the Doppler shift, correcting the spectrum peak frequency according to the Doppler shift, thereby reducing the error caused by the Doppler shift when the radar measures the distance. Meanwhile, the method can increase the chirp duration to improve the maximum measurable distance and the speed accuracy, but will not compress the measurable speed range. The application can be widely applied to the technical field of radar signal processing.

Description

Technical Field

[0001] This invention relates to the field of radar signal processing technology, and in particular to a method and apparatus for calculating target range and velocity based on frequency modulated continuous wave radar. Background Technology

[0002] Currently, with the rapid development of electronic information technology, driver assistance technology in the field of autonomous driving has become a hot research area. Among driver assistance technologies, frequency-modulated continuous wave radar occupies an important position due to its low power consumption, high integration, and minimal impact from weather conditions. Especially in applications on complex roads, there is an urgent need for frequency-modulated continuous wave radar to accurately measure the distance and speed information of the target.

[0003] Currently, frequency-modulated continuous wave radars generally use chirp sequence modulation to measure the range and velocity of targets. When calculating the range of the target, the Doppler shift caused by the radial velocity of the object is ignored. The intermediate frequency signal spectrum is obtained using FFT, and the peak frequency is then derived, which is considered to be generated solely by the distance between the object and the radar. However, since vehicles are in motion, their radial velocity is relatively large, and the Doppler shift caused by velocity is already apparent. Ignoring this shift would affect the accuracy of range measurement. Furthermore, the four performance indicators of existing chirp sequence modulation methods (maximum measurable range, range accuracy, maximum unambiguous velocity, and velocity accuracy) are interdependent; improving one indicator often sacrifices others. For example, with other parameters remaining constant, increasing the chirp duration can improve the maximum measurable range and velocity accuracy, but at the same time, the maximum unambiguous velocity will decrease. Summary of the Invention

[0004] In order to at least partially solve one of the technical problems existing in the prior art, the purpose of this invention is to provide a method and device for calculating target range and velocity based on frequency modulated continuous wave radar.

[0005] The technical solution adopted in this invention is:

[0006] A method for calculating target range and velocity based on frequency modulated continuous wave radar includes the following steps:

[0007] S1. Acquire the first frame signal transmitted by the radar. Mix the chirp transmitted signal and the received signal in the first frame signal to obtain the intermediate frequency (IF) signal. Obtain the spectral peak frequency f of the IF signal spectrum based on the IF signal. TF and the intermediate frequency signal frequency is f TF The phase change Δφ of the signal between adjacent chirps;

[0008] S2. Obtain the second frame signal transmitted by the radar. Mix the chirp transmitted signal and the received signal in the second frame signal to obtain the intermediate frequency (IF) signal. Obtain the spectral peak frequency f of the IF signal spectrum based on the IF signal. IF_next and the intermediate frequency signal frequency is f TF_next The phase change Δφ of the signal between adjacent chirps next The first frame signal and the second frame signal are two adjacent frames.

[0009] S3. Based on the spectral peak frequency f IF Spectral peak frequency f IF_next Obtain the frequency difference, and based on the frequency difference and frame time, obtain the target's relatively low velocity v within two frames of the signal. ina ;

[0010] S4. Calculate the maximum unambiguous velocity v based on the radar transmitted waveform parameters. m_unam The unambiguous velocity v is calculated based on the phase change Δφ. unam ;

[0011] S5, based on velocity v ina Unambiguous speed v unam and the maximum unambiguous velocity v m_unam Calculate the precise velocity v of the target being measured;

[0012] S6. Based on the precise velocity v and the wavelength λ of the center frequency of the transmitted signal, obtain the Doppler frequency shift and correct the spectral peak frequency f. IF This allows us to determine the corrected distance to the target being measured.

[0013] Further, step S5 specifically includes:

[0014] According to the velocity v ina Unambiguous speed v unam and the maximum unambiguous velocity v m_unam Calculate to obtain the integer Z;

[0015] The maximum unambiguous speed v m_unam Multiply by 2Z, then with the unambiguous velocity v unam Add them together to obtain the precise velocity v of the target being measured.

[0016] Further, step S1 specifically includes:

[0017] X chirp transmitted and received signals in the first frame signal are mixed to obtain X intermediate frequency signals;

[0018] The intermediate frequency (IF) signal is sampled by an ADC, with Y points sampled for each IF signal, resulting in an X-row, Y-column matrix.

[0019] Perform a two-dimensional fast Fourier transform on the obtained matrix to obtain the spectral peak frequency f of the intermediate frequency signal spectrum. IF and the intermediate frequency signal frequency is f IF The phase change Δφ of the signal between adjacent chirps.

[0020] Furthermore, each chirp is a continuous sine or cosine wave whose frequency increases linearly with time, and the duration T of each chirp is... chirp It should be large enough to obtain a sufficiently large maximum measurable distance and sufficiently high velocity accuracy.

[0021] Furthermore, it also includes the following steps:

[0022] Due to the increased duration T chirp This leads to the maximum unambiguous speed v m_unam Smaller, meaning the actual phase change It may exceed π, while Δφ ∈ [-π, π] obtained through the two-dimensional fast Fourier transform, and Converted to velocity, it can be expressed as v = v unam +2Zv m_unam If we only need to find Z, we can find the answer. The corresponding precise speed v is used to address the problem of the maximum unambiguous speed decreasing.

[0023] Furthermore, the speed v ina It is obtained through the following calculation method:

[0024] The spectral peak frequency f IF Spectral peak frequency f IF_next Subtracting the two values ​​yields the frequency difference, which represents the change in target distance ΔR between the transmission of the previous and next frame of signals. This difference then represents the target's relatively low velocity during the time interval between the transmission of the previous and next frame of signals.

[0025] Furthermore, the integer Z is calculated in the following manner:

[0026] velocity v ina and unambiguous velocity v unam Subtract and divide by twice the maximum unambiguous speed v m_unam The integer Z is obtained by rounding to the nearest integer. The formula is expressed as follows:

[0027]

[0028] The ROUND function is used to round the number in parentheses to the nearest integer.

[0029] Further, step S6 specifically includes:

[0030] The precise velocity v is obtained as the target's radial velocity at the time of the signal in the previous frame.

[0031] The Doppler frequency shift is calculated based on the precise velocity v and the wavelength λ of the center frequency. According to the Doppler frequency shift f D Eliminate spectral peak frequency f IF The Doppler frequency shift portion of the signal is used to calculate the accurate distance, which is then used as the distance between the target and the radar in the previous frame of signal before transmission.

[0032] Furthermore, it also includes the following steps:

[0033] After obtaining the accurate distance and velocity when the first frame of the signal is obtained, the spectral peak frequency f is... IF_next Assign a value to the spectral peak frequency f IF The phase change Δφ next Assign the value to the phase change Δφ;

[0034] Obtain the third frame of the radar transmission signal and determine the new spectral peak frequency f based on the third frame signal. IF_next and phase change Δφ next The second and third frames are two adjacent frames.

[0035] According to the new spectral peak frequency f IF Spectral peak frequency f IF_next The accurate distance and velocity of the second frame signal are obtained by calculating the phase change Δφ.

[0036] Another technical solution adopted in this invention is:

[0037] A target range and velocity measurement device based on frequency modulated continuous wave radar, comprising:

[0038] At least one processor;

[0039] At least one memory for storing at least one program;

[0040] When the at least one program is executed by the at least one processor, the at least one processor implements the method described above.

[0041] The beneficial effects of this invention are: by calculating the Doppler frequency shift and correcting the spectral peak frequency based on the Doppler frequency shift, the error caused by the Doppler frequency shift when measuring radar distance is reduced, and the maximum measurable distance and speed accuracy are improved. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following description is provided with accompanying drawings of the relevant technical solutions in the embodiments of the present invention or the prior art. It should be understood that the accompanying drawings described below are only for the purpose of clearly illustrating some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a flowchart of a target range and velocity calculation method based on frequency modulated continuous wave radar in an embodiment of the present invention;

[0044] Figure 2 This is a schematic diagram of the structure of the frequency-modulated continuous wave radar system in an embodiment of the present invention;

[0045] Figure 3 This is a schematic diagram showing the amplitude and time relationship of the transmitted signal of the frequency-modulated continuous wave radar system in an embodiment of the present invention;

[0046] Figure 4 This is a schematic diagram illustrating the frequency-time relationship between a frame of transmitted and echo signals of a frequency-modulated continuous wave radar system in an embodiment of the present invention.

[0047] Figure 5 This is a flowchart of the secondary utilization of intermediate frequency signals in an embodiment of the present invention. Detailed Implementation

[0048] The embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. The step numbers in the following embodiments are set only for ease of explanation, and there is no limitation on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0049] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0050] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0051] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0052] like Figure 1 As shown, this embodiment provides a method for calculating target range and velocity based on frequency modulated continuous wave radar, specifically including the following steps:

[0053] Step S1: Control the radar to transmit one frame of signal. Mix the X chirp transmitted and received signals in one frame to obtain X intermediate frequency (IF) signals. Perform ADC (Analog-to-Digital Converter) sampling on the IF signals, sampling Y points for each IF signal, resulting in an X-row, Y-column matrix. Perform a 2D-FFT (Two-Dimensional Fast Fourier Transform) on the matrix to obtain the spectral peak frequency f of the IF signal spectrum. TF The intermediate frequency signal frequency is f TF The phase change Δφ of the signal between adjacent chirps.

[0054] Please see Figure 2 The waveform generator controls the transmitting antenna to transmit a specific transmission signal. The received signal is mixed with the transmitted signal by the receiving antenna, then passed through a low-pass filter, and then sampled at a certain sampling rate before being sent to the signal processing module.

[0055] The transmitted signal is a continuous sine or cosine wave with a frequency that increases linearly with time, repeating X times. Please refer to [link / reference]. Figure 3 Its amplitude changes over time as follows Figure 3 As shown.

[0056] Because the transmitted signal is a continuous sine or cosine wave with a frequency that increases linearly with time, it is received by the receiving antenna as an echo signal only after traveling a distance twice that between the radar and the object. Furthermore, the echo signal may experience a Doppler frequency shift due to the radial velocity between the object and the radar. Therefore, there will be a certain frequency difference between the received and transmitted signals. Please refer to [link to relevant documentation]. Figure 4 The frequency changes of the transmitted and received signals over time in a frame are as follows: Figure 4 As shown.

[0057] The intermediate frequency (IF) signal is obtained by mixing the received signal with the transmitted signal. The frequency of the IF signal is the frequency difference between the received signal and the transmitted signal.

[0058] The 2D-FFT is a two-dimensional fast Fourier transform. By performing a fast Fourier transform on a two-dimensional matrix in both dimensions, the average frequency f of the intermediate frequency signal can be obtained from the peaks of the two-dimensional spectrum. TF The phase change Δφ of the adjacent intermediate frequency signal.

[0059] Step S2: Transmit the next frame signal, and process the next frame signal in the same way as in step S1 to obtain f. TF_next and Δφ next .

[0060] The second frame of transmitted signal is the same as the first frame, but because the distance between the object and the radar may have changed due to the object's movement, f IF with f IF_next By subtracting the two frames, the distance difference between them can be calculated.

[0061] Step S3: f IF and f IF_next Subtracting them gives the frequency difference. Converting the frequency difference to a range difference and dividing by the frame time gives the target's low-precision velocity v during the time interval between the previous and next frame of the signal transmission. ina .

[0062] f TF and f TF_next Subtracting these two values ​​yields the frequency difference, which represents the change in target distance ΔR between the time frame preceding and following signal transmission. The target's relatively inaccurate velocity is also represented during this time frame.

[0063] Step S4: Calculate the maximum unambiguous velocity v based on the radar transmitted waveform parameters. m_unam The unambiguous velocity v is calculated based on Δφ. unam , will u ina and v unam Subtract and divide by v m_unam Rounding to the nearest integer yields the integer Z.

[0064] Using v ina v m_unam and v unam Find the integer (The ROUND function rounds the number in parentheses to the nearest integer.)

[0065] Step S5: Precise velocity v and v0 of the target being measured unam The difference is 2Z times. m_unam Therefore, v unam With 2Z times vm_unam The exact velocity v of the target is obtained by adding them together.

[0066] To improve the accuracy of the maximum measurable distance and velocity, T can be appropriately increased while keeping other parameters constant. chirp Although increasing T chirp This will lead to a decrease in the maximum unambiguous speed, but if the actual speed exceeds the maximum unambiguous speed, the actual speed can still be calculated using the method of this invention.

[0067] The formulas for the maximum measurable distance and velocity accuracy are as follows:

[0068]

[0069]

[0070] Among them, F s The sampling rate for the intermediate frequency signal is T, where c is the speed of light, and T is the sampling rate for the intermediate frequency signal. chirp Let B be the duration of the continuous wave of the transmitted signal, B be the bandwidth of the frequency variation of the transmitted signal, X be the number of continuous waves with linearly increasing frequency in one frame of the signal, and f be the frequency of the continuous wave. c The center frequency of the transmitted signal.

[0071] Due to the increased duration T chirp This leads to a smaller maximum unambiguous velocity, i.e., a smaller actual phase change. It may exceed π, while Δφ ∈ [-π, π] obtained by 2D-FFT, and Converted to speed, it can be expressed as v =v unam +2Zv m_unam If we only need to find Z, we can find the answer. The corresponding v addresses the issue of the maximum unambiguous speed decreasing.

[0072] Step S6: Divide the Doppler frequency shift by twice the velocity v and the wavelength λ of the center frequency of the emitted wave, and then correct f. TF This allows us to determine the corrected distance to the target being measured.

[0073] Since the intermediate frequency signal frequency is the frequency difference between the received signal and the transmitted signal, this frequency consists of two parts.

[0074] The first part is due to the delay caused by the transmitted signal returning to the receiving antenna after propagating along the propagation path, resulting in the received signal lagging behind the transmitted signal. Furthermore, since the transmitted signal is a continuous sine wave with a frequency that increases linearly with time, there is a fixed frequency difference between the transmitted and received signals. In other words, the first part is caused by the distance between the object and the radar.

[0075] The second part is caused by the Doppler frequency domain. Since there is a radial velocity between the object and the radar, the microwave will generate a Doppler frequency shift during propagation. That is, the second part is caused by the radial velocity between the object and the radar.

[0076] Therefore, the Doppler frequency shift can be obtained by calculating the velocity v, and the intermediate frequency signal frequency can be subtracted from the Doppler frequency shift to obtain the frequency caused only by the distance between the object and the radar. This frequency can be used to calculate the distance between the object and the radar that is not affected by the Doppler frequency shift.

[0077] Step S7: f TF_next and Δφ next Assign values ​​to f respectively TF And Δφ. The detection process continuously repeats steps S2-S7 to obtain the real-time distance and velocity of the target.

[0078] During real-time detection, f is calculated using the nth frame signal and the (n+1)th frame signal. IF , Δφ and f IF_next , Δφ next Then, the accurate distance and velocity when transmitting the nth frame signal are determined; next, when transmitting the (n+2)th frame signal, f is... IF_next Assigned to f IF , Δφ next The value is assigned to Δφ, and the average frequency of the intermediate frequency signal of the (n+2)th frame and the phase change of the adjacent intermediate frequency signals are assigned to f. IF_next and Δφ next This allows us to calculate the precise distance and velocity at the time of transmitting the (n+1)th frame of signal; and so on. For the detailed process, please refer to [link to relevant documentation]. Figure 5 .

[0079] In summary, compared with existing technologies, this invention reduces the error caused by Doppler frequency shift when measuring radar distance, and improves the accuracy of maximum measurable distance and velocity. Furthermore, it does not compress the measurable velocity range; although the maximum unambiguous velocity is reduced, it can still be calculated even if the target velocity exceeds the maximum unambiguous velocity. Therefore, this invention improves measurement accuracy while maintaining the measurable velocity range, meeting the requirements for high-precision distance and velocity measurement applications of fast-moving objects.

[0080] This embodiment also provides a target range and velocity measurement device based on frequency modulated continuous wave radar, including:

[0081] At least one processor;

[0082] At least one memory for storing at least one program;

[0083] When the at least one program is executed by the at least one processor, the at least one processor implements Figure 1The method shown.

[0084] This embodiment provides a target range and velocity calculation device based on frequency-modulated continuous wave radar. It can execute a target range and velocity calculation method based on frequency-modulated continuous wave radar provided in the method embodiment of the present invention. It can execute any combination of implementation steps of the method embodiment and has the corresponding functions and beneficial effects of the method.

[0085] This application also discloses a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device can read the computer instructions from the computer-readable storage medium and execute the computer instructions, causing the computer device to perform... Figure 1 The method shown.

[0086] In some alternative embodiments, the functions / operations mentioned in the block diagrams may not occur in the order shown in the operation diagrams. For example, depending on the functions / operations involved, two consecutively shown blocks may actually be executed substantially simultaneously, or the blocks may sometimes be executed in reverse order. Furthermore, the embodiments presented and described in the flowcharts of this invention are provided by way of example to provide a more comprehensive understanding of the technology. The disclosed methods are not limited to the operations and logic flows presented herein. Alternative embodiments are contemplated in which the order of various operations is altered and sub-operations described as part of a larger operation are executed independently.

[0087] Furthermore, although the invention has been described in the context of functional modules, it should be understood that, unless otherwise stated, one or more of the described functions and / or features may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in a separate physical device or software module. It is also understood that a detailed discussion of the actual implementation of each module is unnecessary for understanding the invention. Rather, given the properties, functions, and internal relationships of the various functional modules in the apparatus disclosed herein, the actual implementation of the module will be understood within the scope of conventional skill of an engineer. Therefore, those skilled in the art can implement the invention as set forth in the claims using ordinary techniques without excessive experimentation. It is also understood that the specific concepts disclosed are merely illustrative and not intended to limit the scope of the invention, which is determined by the full scope of the appended claims and their equivalents.

[0088] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0089] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0090] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0091] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0092] In the foregoing description of this specification, references to terms such as "one embodiment," "another embodiment," or "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0093] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0094] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A method for calculating target range and velocity based on frequency modulated continuous wave radar, characterized in that, Includes the following steps: S1. Acquire the first frame signal transmitted by the radar. Mix the chirp transmitted signal and the received signal in the first frame signal to obtain the intermediate frequency (IF) signal. Obtain the spectral peak frequency of the IF signal spectrum based on the IF signal. and the intermediate frequency signal frequency is Phase change of the signal between adjacent chirps ; S2. Obtain the second frame signal transmitted by the radar. Mix the chirp transmitted signal and the received signal in the second frame signal to obtain the intermediate frequency (IF) signal. Obtain the spectral peak frequency of the IF signal spectrum based on the IF signal. and the intermediate frequency signal frequency is Phase change of the signal between adjacent chirps The first frame signal and the second frame signal are two adjacent frames. S3. Based on the spectral peak frequency Spectral peak frequency The frequency difference is obtained, and the target's velocity (which has low precision) within two frames of the signal is obtained based on the frequency difference and the frame time. ; S4. Calculate the maximum unambiguous velocity based on the radar transmitted waveform parameters. According to phase change Calculate unambiguous speed ; S5, based on speed Unambiguous speed and maximum unambiguous speed Calculate the precise velocity of the target being measured. ; S6, based on precise speed and the wavelength of the center frequency of the transmitted signal Obtain the Doppler frequency shift and correct the spectral peak frequency. This allows us to calculate the corrected distance to the target being measured. Step S1 specifically includes: X chirp transmitted and received signals in the first frame signal are mixed to obtain X intermediate frequency signals; The intermediate frequency (IF) signal is sampled by an ADC, with Y points sampled for each IF signal, resulting in an X-row, Y-column matrix. Perform a two-dimensional fast Fourier transform on the obtained matrix to obtain the spectral peak frequency of the intermediate frequency signal. and the intermediate frequency signal frequency is Phase change of the signal between adjacent chirps Each chirp is a continuous sine or cosine wave whose frequency increases linearly with time, and the duration of each chirp is... It should be large enough to obtain a sufficiently large maximum measurable distance and sufficiently high velocity accuracy; Step S6 specifically includes: Get precise speed , which is the radial velocity of the target in the previous frame of signal; Based on precise speed and the wavelength of the center frequency Calculate the Doppler frequency shift According to Doppler frequency shift Eliminate spectral peak frequencies The Doppler frequency shift portion of the signal is used to calculate the accurate distance, which is then used as the distance between the target and the radar in the previous frame of signal before transmission.

2. The target range and velocity calculation method based on frequency modulated continuous wave radar according to claim 1, characterized in that, Step S5 specifically includes: According to speed Unambiguous speed and maximum unambiguous speed Calculate to obtain an integer ; Maximum unambiguous speed Multiply by 2 After that, with unambiguous speed Add them together to obtain the precise speed of the target being measured. .

3. The target range and velocity calculation method based on frequency modulated continuous wave radar according to claim 1, characterized in that, It also includes the following steps: Due to the increased duration This leads to the maximum unambiguous speed Smaller, meaning the actual phase change It may exceed The result obtained through two-dimensional fast Fourier transform ,and Converted to speed, it can be expressed as Only need to find Then we can find out Corresponding precise speed This is to address the issue of the maximum unambiguous speed decreasing.

4. The target range and velocity calculation method based on frequency modulated continuous wave radar according to claim 1, characterized in that, speed It is obtained through the following calculation method: spectral peak frequency Spectral peak frequency Subtracting the two values ​​yields the frequency difference, which represents the change in the target's distance between the frames before and after the transmission of the signal. The target's speed, which is not very accurate, is during the time between transmitting the signal in the previous frame and the next frame. .

5. The target range and velocity calculation method based on frequency modulated continuous wave radar according to claim 2, characterized in that, The integer It is obtained through the following calculation method: speed and unambiguous speed Subtract and divide by twice the maximum unambiguous speed Round to the nearest integer to obtain the integer. The formula is expressed as follows: The ROUND function is used to round the number in parentheses to the nearest integer.

6. The target range and velocity calculation method based on frequency modulated continuous wave radar according to claim 1, characterized in that, It also includes the following steps: After obtaining the accurate distance and velocity when the first frame of the signal is obtained, the spectral peak frequency is... Assigned to the peak frequency Phase change Assigning to phase change ; Obtain the third frame of the radar transmission signal and determine the new spectral peak frequency based on the third frame signal. and phase change The second and third frames are two adjacent frames. Based on the new spectral peak frequencies Spectral peak frequency and phase change Determine the accurate distance and velocity for the second frame of the signal.

7. A target range and velocity calculation device based on frequency modulated continuous wave radar, characterized in that, include: At least one processor; At least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method according to any one of claims 1-6.

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