Apparatus, method for acquiring angle information of static target, and simultaneous localization and mapping system

Abstract

The application provides a device and method for obtaining angle information of a static target and a simultaneous localization and mapping system. The device comprises: an FMCW sensor, which is used for performing two-dimensional fast Fourier transform on a received echo signal and then performing constant false alarm processing to obtain a range-Doppler spectrum including Doppler velocity data of the static target; and a processor, which is used for performing vector calculation according to a travel speed of the sensor and the Doppler velocity data, converting the range-Doppler spectrum into a range-angle spectrum, and then obtaining horizontal angle information of the static target relative to the sensor. The application can realize high-precision angle measurement of the static target at a low cost and is convenient for popularization and application in the fields of automatic driving, automatic parking, robot navigation and the like.

Description

[0001] This application is a divisional application of the application filed on May 31, 2022, with application number 202210612269.X, entitled "Method, apparatus, and SLAM system for acquiring angle information of static targets". Technical Field

[0002] This disclosure relates to the field of sensor technology, and specifically to an apparatus, method, and real-time positioning and mapping system for acquiring angle information of static targets. Background Technology

[0003] Currently, sensors such as Synthetic Aperture Radar (SAR) are generally used to achieve high-precision measurement of the angle of static targets. However, because the calculation of traditional methods is very complex and expensive, it is difficult for related applications to be quickly promoted and applied. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides an apparatus, method, and real-time localization and mapping (RTM) system for acquiring angle information of static targets. The apparatus includes: an FMCW sensor for performing a two-dimensional fast Fourier transform on the received echo signal followed by constant false alarm rate (CFAR) processing to obtain a range-Doppler spectrum including Doppler data of the static target; and a processor for performing vector calculations based on the sensor's travel speed and Doppler data to convert the range-Doppler spectrum into a range-angle spectrum, thereby obtaining the horizontal angle information of the static target relative to the sensor. This application also provides antenna configurations and corresponding signal processing strategies for different sensor installation positions on the side, front, or rear of the carrier. Furthermore, this application provides a method for directly converting the range-Doppler spectrum without CFAR processing, a velocity fusion method, and an RTM system incorporating the aforementioned apparatus. This application enables high-precision angle measurement of static targets at low cost, facilitating its widespread application in fields such as autonomous driving, automatic parking, and robot navigation.

[0005] In a first aspect, this disclosure provides an apparatus for acquiring angle information of a static target, comprising: an FMCW sensor, configured to perform a two-dimensional fast Fourier transform on the received echo signal and then perform constant false alarm rate processing to obtain a range-Doppler spectrum, wherein the range-Doppler spectrum includes Doppler data of the static target; and a processor, configured to perform vector calculations based on the Doppler data and the traveling speed of the FMCW sensor to convert the range-Doppler spectrum into a range-angle spectrum, thereby obtaining the horizontal angle information of the static target relative to the FMCW sensor.

[0006] In some embodiments, the vector calculation is based on the formula Vr=V / cos(θ) or Vr=V·sin(θ)·cos(β), where V is the travel speed, Vr is the radial speed, θ is the horizontal angle, and β is the pitch angle.

[0007] In some embodiments, the device further includes a carrier, the sensor is fixedly mounted on the carrier, and the travel speed output by the carrier is the travel speed of the sensor.

[0008] In some embodiments, the sensor includes a millimeter-wave radar chip, and the processor is an on-chip processing unit located within the millimeter-wave radar chip or an external processing unit on the carrier.

[0009] Secondly, this disclosure provides another device for acquiring angle information of a static target, comprising: an FMCW sensor, fixedly mounted on a carrier, for acquiring Doppler data of the static target; and a processor for acquiring horizontal angle information of the static target relative to the FMCW sensor based on the traveling speed of the FMCW sensor and the Doppler data. In the direction of travel of the carrier, the FMCW sensor is mounted on the side of the carrier, and the FMCW sensor has at least one transmitting antenna and at least one receiving antenna, the total number of transmitting antennas and receiving antennas being less than 4.

[0010] In some embodiments, the processor is further configured to perform field-of-view compression processing on the signal received by the FMCW sensor in the vertical direction to obtain Doppler data of the static target.

[0011] Thirdly, this disclosure provides another device for acquiring angle information of a static target, comprising: an FMCW sensor, fixedly mounted on a carrier, for acquiring Doppler data of the static target; and a processor for acquiring horizontal angle information of the static target relative to the FMCW sensor based on the travel speed of the FMCW sensor and the Doppler data; wherein, in the direction of travel of the carrier, the FMCW sensor is mounted on the side of the carrier, and the FMCW sensor has at least two transmitting antennas or at least two receiving antennas distributed along the vertical direction; the processor is further configured to compensate for the horizontal angle information using the height value of the static target obtained by the FMCW sensor.

[0012] Fourthly, this disclosure provides another apparatus for acquiring angle information of a static target, comprising: an FMCW sensor, fixedly mounted on a carrier, for acquiring Doppler data of the static target; and a processor for acquiring horizontal angle information of the static target relative to the FMCW sensor based on the travel speed of the FMCW sensor and the Doppler data; wherein, in the direction of travel of the carrier, the FMCW sensor is mounted on the front or rear of the carrier, and the FMCW sensor has at least two transmitting antennas or at least two receiving antennas distributed along the horizontal direction; the processor is further configured to determine whether the static target is to the left or right of the FMCW sensor based on the detection results of the at least two transmitting antennas or at least two receiving antennas distributed along the horizontal direction.

[0013] Fifthly, this disclosure provides a method for obtaining angle information of static targets, applied to a moving FMCW sensor, comprising: obtaining the moving speed of the sensor; performing a two-dimensional fast Fourier transform on the echo signal received by the sensor to obtain the entire range-Doppler spectrum; directly converting the entire range-Doppler spectrum into a range-angle spectrum without constant false alarm rate processing to obtain high-precision angle information of each static target; and obtaining the horizontal angle information of the static target relative to the sensor based on the moving speed and the range-angle spectrum.

[0014] Sixthly, this disclosure provides another method for acquiring angle information of a static target, applied to a moving FMCW sensor, the sensor being fixedly mounted on a carrier, the method comprising: acquiring the real-time moving speed of the carrier; acquiring the speed obtained by an inertial motion velocimeter mounted on the carrier; fusing the speed obtained by the inertial motion velocimeter with the real-time moving speed using a filter to obtain a fused moving speed; acquiring Doppler data of the static target using the sensor; and acquiring the horizontal angle information of the static target relative to the sensor based on the fused moving speed and the Doppler data.

[0015] In a seventh aspect, this disclosure provides an instant positioning and mapping system, including the apparatus described in any one of the first to fourth aspects above, wherein the system is used to acquire horizontal angle information of the static target relative to the sensor, and to perform instant positioning and / or map construction.

[0016] Beneficial effects: The technical solution disclosed herein achieves high-precision measurement of the horizontal angle information of a static target simply, quickly, and at low cost by performing vector calculations on the sensor's travel speed and the Doppler data obtained from target detection. Specifically: The device described in the first aspect obtains a range-Doppler spectrum and converts it into a range-angle spectrum by performing 2D-FFT on the echo signal and then continuing CFAR processing, which can effectively utilize Doppler information to achieve high-resolution angle measurement.

[0017] The devices described in the second to fourth aspects are configured with corresponding antenna structures (one transmit and one receive, vertical array, horizontal array) and corresponding signal processing strategies (compressed field of view, height compensation, left and right judgment) for different installation positions of the sensor on the carrier (side, front, and rear). They can achieve high-precision angle measurement in different application scenarios, and the hardware cost is low and easy to promote and apply.

[0018] The method described in the fifth aspect, by directly converting the range-Doppler spectrum without constant false alarm rate (CFAR) processing, can retain information about all static targets and avoid target misses caused by CFAR processing.

[0019] The method described in the sixth aspect, by fusing the real-time speed of the carrier with the speed measured by the inertial motion velocimeter, can improve the accuracy and timeliness of speed acquisition, thereby improving the accuracy of angle measurement.

[0020] The real-time positioning and mapping system described in the seventh aspect uses the aforementioned device to acquire high-precision angle information, enabling high-precision positioning and mapping at low cost, and is applicable to fields such as vehicle automatic parking and robot navigation.

[0021] In addition, this disclosure provides a method for acquiring angular information of a static target, which can be applied to a frequency-modulated continuous wave (FMCW) sensor in motion. The method may include: The travel speed of the sensor is obtained; The Doppler data of the static target are acquired using the sensor; and The horizontal angle information of the static target relative to the sensor is obtained based on the travel speed and the Doppler data.

[0022] In the above embodiments, by performing vector calculations on the sensor's travel speed and the Doppler data obtained from target detection, high-precision measurement of the horizontal angle information of static targets can be achieved simply, quickly, and at low cost, thereby facilitating the rapid promotion and application of related applications.

[0023] It should be noted that the aforementioned speed and Doppler data can be acquired simultaneously or sequentially. For example, the speed can be acquired first and then the Doppler data, or vice versa. The specific method can be set according to actual needs. Furthermore, the speed and Doppler data are preferably data information corresponding to the same moment, but they can also be data information corresponding to the same time period within the acceptable error range of the design (such as the average speed, median speed, etc. corresponding to that time period).

[0024] In an optional embodiment, acquiring Doppler data of the static target using the sensor may include: After performing a two-dimensional fast Fourier transform (2D-FFT) on the echo signal received by the sensor, constant false alarm rate (CFAR) processing is continued to obtain the Doppler data. That is, continuing CFAR after 2D-FFT reduces the amount of subsequent calculation by first filtering the detection points (i.e. removing some false targets).

[0025] In addition, in the embodiments of this application, if CFAR processing is not required, the entire range-Doppler map obtained by 2D-FFT can be directly converted into a range-Angle map by the relevant steps in the embodiments of this application, thereby easily and quickly obtaining high-precision angle information of each static target.

[0026] In some optional embodiments, in the embodiments of this application, when performing 2D-FFT processing, the number of points processed by Doppler FFT is positively correlated with the resolution of the final obtained angle information, that is, the more points processed by Doppler FFT, the higher the resolution of the final obtained angle information of the static target.

[0027] In some optional embodiments, obtaining the travel speed of the sensor includes: The travel speed is estimated based on the result of the two-dimensional fast Fourier transform. That is, the current travel speed of the sensor relative to the ground can be obtained by processing the echo signal by the sensor itself. Then, the angle of the static target can be detected by using this travel speed, so that the travel speed of the sensor can be obtained without the need for other speed measuring devices.

[0028] Optionally, the sensor can be fixedly mounted on a carrier, and acquiring the travel speed of the sensor includes: The real-time speed of the carrier is obtained as the speed of the sensor. Since the sensor is fixedly mounted on the carrier, it can be assumed that the speed of the carrier is the same as the speed of the sensor. Then, some speed measuring devices on the carrier are used to obtain the speed in real time.

[0029] In some optional embodiments, the stability of angle measurement in this application embodiment can be ensured by using the travel speed of the carrier and the travel speed measured by the sensor to perform mutual correction, fusion, or backup.

[0030] In some alternative embodiments, the carrier may be a vehicle, and the sensor may be an onboard radar, such as a millimeter-wave radar; acquiring the real-time speed of the carrier may include: The real-time travel speed is obtained based on the vehicle's bus.

[0031] In some optional embodiments, the vehicle is further equipped with an inertial measurement unit (IMU), and the method further includes: The speed obtained by the inertial motion velocimetry device is fused with the real-time travel speed using a filter (e.g., by using a Kalman filter or other similar filters), and the fused speed is used as the travel speed of the sensor to further improve the accuracy and timeliness of obtaining the travel speed.

[0032] It should be noted that when using the estimated velocity obtained by the sensor itself from the 2D-FFT result, a similar velocity fusion process can be used to improve the accuracy of the final acquired travel velocity. For example, the estimated value can be fused with the IMU output. In some optional embodiments, when the sensor is mounted on the side of the carrier in the direction of the carrier's travel, the sensor has a transmitting antenna and a receiving antenna; the acquisition of Doppler data of the static target using the sensor may include: After the signal received by the sensor is processed by compressing the field of view in the vertical direction, Doppler data of the static target is obtained.

[0033] In some optional embodiments, when the sensor is mounted on the side of the carrier in the direction of travel of the carrier, the sensor has at least two transmitting antennas or at least two receiving antennas distributed in the vertical direction; the method may further include: The height value of the static target is obtained using the sensor; and The horizontal angle information is compensated using the height value of the static target.

[0034] In some alternative embodiments, when the sensor is mounted on the front or back of the carrier in the direction of the carrier's travel, the sensor has at least two transmitting antennas or at least two receiving antennas distributed in the horizontal direction, such as a two-transmitting-one-receiving antenna structure, or a two-receiving-one-transmitting antenna structure, etc.

[0035] In some optional embodiments, the method may further include: The system determines the sensor's installation method and employs corresponding strategies or algorithms based on different installation methods to automatically achieve high-precision angle detection of static targets.

[0036] In some optional embodiments, the method may further include: After adjusting the maximum unambiguous speed of the sensor to the sensor's travel speed, the Doppler data of the static target is then acquired using the sensor.

[0037] It should be noted that the sensor's maximum unambiguous speed can be adjusted in real time according to the sensor's travel speed to further improve the accuracy and timeliness of angle measurement.

[0038] In some optional embodiments, adjusting the maximum unambiguous speed of the sensor to the traveling speed of the sensor may include: Adjust the initial sweep frequency of the sensor and / or the period of the chirped signal emitted by the sensor so that the maximum unambiguous speed of the sensor is the traveling speed of the sensor.

[0039] In some alternative embodiments, the sensor may be a millimeter-wave radar.

[0040] On the other hand, this application also provides an apparatus for acquiring angle information of a static target, which may include: An FMCW sensor is used to acquire Doppler data of the static target; A processor is used in any embodiment of this application to obtain horizontal angle information of the static target relative to the sensor.

[0041] In some alternative embodiments, the apparatus may further include: The sensor is fixedly mounted on the carrier. The travel speed output by the carrier is the travel speed of the sensor.

[0042] In some alternative embodiments, the sensor may include a millimeter-wave radar chip. The processor is either an on-chip processing unit located within the millimeter-wave radar chip or an external processing unit on the carrier.

[0043] In some alternative embodiments, the millimeter-wave radar chip may be an AiP (Antenna in Package) chip.

[0044] Furthermore, this application also provides a Simultaneous Localization and Mapping (SLAM) system, which may include the apparatus described in any embodiment of this application, for acquiring the horizontal angle information of the static target relative to the sensor.

[0045] In some optional embodiments, the sensor is also used to acquire distance information of the static target relative to the sensor. The system performs real-time positioning and / or map construction based on the horizontal angle information and the distance information.

[0046] In some optional embodiments, the sensor is also used to acquire information about the static target. The system performs two-dimensional real-time positioning and / or map construction based on the horizontal angle information, the distance information, and the static target information, or three-dimensional real-time positioning and / or map construction. Attached Figure Description

[0047] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments of this disclosure with reference to the accompanying drawings.

[0048] Figure 1 This is a flowchart illustrating a method for obtaining angle information of a static target according to an embodiment of this application; Figure 2a and Figure 2b The waveform diagrams of frequency-modulated continuous wave signals in the time domain and frequency domain are shown respectively in the prior art; Figure 3a and Figure 3b The diagrams show the signal paths of the transmitting and receiving antennas in the prior art based on MIMO antenna arrays. Figure 4a This diagram illustrates a scenario in the horizontal plane for measuring the azimuth angle of a static target based on a carrier, as provided in this disclosure. Figure 4b This diagram illustrates a scenario in the vertical direction for measuring the pitch angle of a static target based on a carrier, as provided in this disclosure. Figure 5a This diagram shows a schematic block diagram of the structure of the carrier provided in this disclosure; Figure 5b A schematic diagram showing the sensor mounting position in the vertical projection of the carrier provided in this disclosure is provided. Figures 6a-6h Show each Figure 5a A schematic diagram showing the distribution of the second detection unit in various embodiments of the carrier shown. Figure 7a A flowchart illustrating the angle resolution measurement method based on frequency-modulated continuous wave radar provided in this disclosure is shown. Figure 7b Based on Figure 7a The diagram illustrates a parking scenario using the method described above. Figure 7c Based on Figures 7a-7b The diagram illustrates how the method obtains angle information in a given scenario. Figures 8-10 Show each Figure 7a The diagram shows a model of the angular resolution measurement method in different application scenarios. Figure 11 Show Figures 8-10 A schematic diagram of one of the models in a further implementation; Figure 12 Show Figures 8-10 A schematic diagram of one of the models in a further implementation. Detailed Implementation

[0049] To facilitate understanding of this disclosure, a more complete description will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the present disclosure. However, this disclosure may be implemented in various forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the contents of this disclosure.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure.

[0051] Example 1: Figure 1 This is a flowchart illustrating a method for obtaining angle information of a static target according to an embodiment of this application. Figure 1 As shown, a method for acquiring angle information of a static target, applicable to a moving FMCW sensor, may include the following steps: Step S1: Obtain the travel speed of the sensor.

[0052] Specifically, the current speed can be estimated based on the result of the sensor's two-dimensional fast Fourier transform (i.e., 2D-FFT). In other words, the current speed of the sensor relative to the ground can be obtained based on the sensor's own processing of the echo signal.

[0053] Meanwhile, when the sensor is fixedly installed on the carrier (such as a car, a robot vacuum cleaner, etc.), the current speed of the carrier can be obtained based on the speed measuring device (such as a laser velocimeter, an inertial motion velocimeter, etc.) installed on the carrier itself. That is, at this time, the speed of the sensor is the same as the speed of the carrier.

[0054] In addition, the travel speed obtained by the above-mentioned speed measuring device and the travel speed measured by the sensor can be mutually corrected, fused or backed up to ensure the accuracy and stability of the angle measurement in the embodiments of this application.

[0055] When the aforementioned carrier is a vehicle, the real-time travel speed can be obtained through the vehicle's bus as the travel speed. The speed obtained by the inertial motion speed measuring device can be fused with the real-time travel speed by using a filter, and the fused speed can be used as the travel speed of the sensor.

[0056] In short, the current speed of the sensor can be obtained in real time and accurately through the sensor itself or other related devices.

[0057] Step S2: Use sensors to acquire Doppler data of the static target.

[0058] Specifically, Doppler data of static targets can be obtained by performing signal processing such as two-dimensional fast Fourier transform (2D-FFT) on the echo signals received by the sensor. At the same time, constant false alarm rate (CFAR) processing can be continued after 2D-FFT. That is, CFAR is continued after 2D-FFT, which can effectively reduce the amount of subsequent calculation by first screening the detection points (i.e. removing some false targets).

[0059] In addition, since the number of points processed by Doppler FFT is positively correlated with the resolution of the final angle information during 2D-FFT processing, the resolution of the angle information of static targets can be further improved by increasing or increasing the number of points of Doppler FFTD.

[0060] Step S3: Perform vector calculations based on the travel speed and Doppler data to obtain the horizontal angle information of the static target relative to the sensor.

[0061] In the above embodiments, by performing vector calculations on the sensor's travel speed and the Doppler data obtained from target detection, high-precision measurement of the horizontal angle information of a static target can be achieved simply, quickly, and at low cost.

[0062] It should be noted that the above steps S1 and S2 can be performed simultaneously (or partially simultaneously), or in any order; at the same time, the preferred travel speed and Doppler data are data information corresponding to the same moment, or they can be data information corresponding to the same time period within the acceptable error range of the design (such as the average speed, median speed, etc. corresponding to that time period).

[0063] In some alternative embodiments, for sensors installed on different sides of the carrier, the angle information of the obtained static target can be compensated by setting a certain antenna structure or signal processing method, so as to further improve the accuracy of the measurement results.

[0064] For example, when a radar is mounted on the side of a vehicle (such as a side-mounted radar), it only needs a transmit and receive antenna structure to easily measure the angle information of static targets on the corresponding side of the vehicle. Furthermore, in such scenarios, the Doppler data of the static target can be further improved by compressing the field of view in the vertical direction, thus further enhancing the accuracy of the final measured angle.

[0065] When the radar is installed on the side and has at least two transmitting antennas or at least two receiving antennas distributed along the vertical direction, since the antenna array has the function of measuring the target height, the height value of the static target detected by the sensor can be used to compensate for the obtained horizontal angle information, so as to further improve the accuracy of the measured angle.

[0066] Similarly, when the radar is installed at the front (e.g., front radar) and / or at the rear (e.g., rear radar), the radar may have at least two transmitting antennas or at least two receiving antennas distributed along the horizontal direction, such as a two-transmit, one-receive antenna structure, or a two-receive, one-transmit antenna structure, or a multi-transmit, multi-receive antenna structure, etc. Since the antenna structure at this time has the function of measuring the horizontal angle, the obtained horizontal angle can be further calibrated to determine whether the obtained angle is a left tilt angle or a right tilt angle.

[0067] It should be noted that since radars may be installed on the front, back, sides and / or corners of a car, different radars installed in different locations can use different algorithms to measure the horizontal angle of a static target. Therefore, as a system, it is also possible to first determine the installation method of the radar and then call the corresponding algorithm (software or hardware) to achieve accurate measurement of the corresponding horizontal angle.

[0068] Furthermore, when radar is installed at a vehicle corner (such as an angle radar), to further improve the accuracy of angle measurement, a combination of frontal and side mounting schemes can be used, and these schemes can also be combined with each other. For example, for an angle radar, its antenna can have at least two transmitting antennas or at least two receiving antennas that can be distributed horizontally, and it can also incorporate FoV technology. It can also compensate for the horizontal angle by utilizing the height of an object, and similarly, it can use a horizontally distributed antenna structure to achieve tilt angle measurement correction.

[0069] In some alternative embodiments, to improve the radar's angle measurement performance, some performance parameters of the radar can be adjusted to complement the vehicle's movement. For example, the radar's maximum unambiguous velocity can be adjusted based on the current movement speed, so that the maximum unambiguous velocity that the radar can measure is equal to the current radar movement speed, thereby further improving the accuracy of angle measurement. For example, by adjusting the initial sweep frequency of the FMCW radar and / or the period of the transmitted chirped signal, the radar's maximum unambiguous velocity value can be made equal to or close to the movement speed value.

[0070] Example 2: This application also provides an apparatus for acquiring angle information of a static target, which may include an FMCW sensor and a processor, etc. The FMCW sensor can be used to acquire Doppler data of the static target, while the processor can acquire the horizontal angle information of the static target relative to the sensor based on the method described in any embodiment of this application.

[0071] In some alternative embodiments, the sensor may include a millimeter-wave radar chip, in which case the processor may be an on-chip processing unit located within the millimeter-wave radar chip or an external processing unit on a carrier.

[0072] It should be noted that the method for obtaining the angle information of a static target in the embodiments of this application and the device for obtaining the angle information of a static target can support each other, and the related technical contents are compatible and applicable to each other without contradiction.

[0073] Example 3: This application also provides a real-time positioning and mapping system, which may include the apparatus of any embodiment of this application for acquiring horizontal angle information of a static target relative to a sensor. Simultaneously, it may utilize the aforementioned sensor or other measuring devices to synchronously acquire information such as pitch angle and distance of the static target, thereby achieving high-resolution detection of the static target in dimensions such as distance and angle, and thus realizing high-precision real-time positioning and / or map building. When the sensor and method in the embodiments of this application can simultaneously achieve high-resolution detection in both distance and angle dimensions, compared to traditional solutions, it can significantly reduce product manufacturing costs while ensuring accuracy. Furthermore, it is computationally simple, highly stable, and easy to implement and promote.

[0074] The following section uses automotive millimeter-wave radar as an example to provide a detailed explanation of the solution proposed in this application, based on the SLAM application scenario: In automotive active safety driving technology, millimeter-wave radar, with its significant advantages of all-weather and all-time operation, is gradually becoming an indispensable detection sensor. With continuous technological advancements and increased computing power of processing chips, millimeter-wave radar is gradually developing towards higher resolution. For example, applications such as Simultaneous Localization and Mapping (SLAM) using radar require high-resolution measurements of static objects.

[0075] The most widely used millimeter-wave radar technology currently is frequency-modulated continuous wave (FMCW). The waveforms of FMCW signals in the time and frequency domains are as follows: Figure 2a and Figure 2b As shown, each such pulse signal is called a chirp. In the frequency domain, the key parameters of a chirp are: starting frequency fc, bandwidth B, and duration Tc. Once these three parameters are determined, the slope S (representing the rate of change of frequency) can be calculated. The range resolution of frequency-modulated continuous wave radar can generally be achieved by increasing the bandwidth of the modulating signal, while angular resolution requires increasing the antenna aperture. Multi-input multi-output (MIMO) antenna arrays with separate transmit and receive signals are considered an important technology for increasing antenna aperture. Considering implementation complexity, hardware cost, and size limitations, automotive millimeter-wave radars generally use MIMO antenna arrays based on time-division multiplexing (TDM) technology. The signal paths of the transmitting and receiving antennas based on a MIMO antenna array are as follows... Figure 3a and Figure 3b As shown.

[0076] While MIMO based on TDM technology can increase antenna aperture and improve angular resolution, it has its own drawbacks. First, TDM itself reduces the sampling rate at slower times, making the maximum unambiguous velocity inversely proportional to the number of transmitting antennas. Second, the phase transformation caused by the Doppler frequency of the moving target during the switching time of different transmitting antennas couples to various receiving channels, affecting the correct synthesis of the receiving antenna aperture. This results in incorrect angle measurements of targets outside the maximum unambiguous velocity range, leading to lower accuracy. Furthermore, the computational load of the measurement data is extremely high, especially when there are many transmitting and receiving antennas, making it prohibitively expensive and significantly reducing its practicality.

[0077] Currently, radar systems used for short-range detection mostly employ continuous wave technology to avoid introducing unnecessary range detection blind spots with pulse signals. High-energy transmitted signals from the transmitting antenna leak directly to the receiving antenna and into the receiver. The high power can cause the receiver's active components to saturate and malfunction, and in severe cases, even burn out the receiver's active components. To suppress signal leakage, one solution is to use separate transmitting and receiving antennas, with isolation measures between them, to reduce the leakage signal entering the receiver.

[0078] In many applications, it is important to be able to decompose two objects in close proximity into two independent objects. The minimum distance between two objects, allowing them to be detected as separate objects, is called range resolution. This primarily depends on the chirp sweep bandwidth that the radar sensor can provide. The larger the sweep bandwidth, the higher the range resolution.

[0079] In applications such as reversing assistance and parking, it may be necessary to separate objects with small speed differences, which requires good speed resolution. Speed ​​resolution mainly depends on the duration of the transmission frame; that is, increasing the number of chirps in the frame can improve speed resolution.

[0080] To locate a target in space, the target's angle must also correspond to the distance. In a radar system, the angle is estimated by receiving reflected signals from multiple target receiving antennas spaced a certain distance *d* apart. The signal arriving at each consecutive receiving antenna is delayed by *d*sin(θ), and this "delay" produces a phase shift. The phase shift between each receiving antenna is used to estimate the target's angle (θ), such as... Figure 3a and Figure 3b As shown.

[0081] Traditionally, high range resolution can be achieved using high-bandwidth frequency sweeping, while high angular resolution typically requires a larger antenna aperture, specifically a large-aperture MIMO radar or Synthetic Aperture Radar (SAR). However, large-aperture MIMO radar is expensive and has lower accuracy, while SAR involves complex calculations in angular resolution measurements.

[0082] Based on this, the following will describe in detail the method and apparatus for measuring the azimuth angle of a static target based on a carrier. The method and apparatus are low in cost, simple to calculate and easy to implement, and require only a few transmit and receive channels to achieve ultra-high angular resolution, thus effectively improving the practicality of the angular resolution measurement method.

[0083] Figure 4a This diagram illustrates a scenario in the horizontal plane for measuring the azimuth angle of a static target based on a carrier, as provided in this disclosure. Figure 4b This illustration shows a scenario of vertical elevation angle measurement of a static target based on a carrier, as provided in this disclosure. Figure 5a A schematic block diagram of the structure of the carrier provided in this disclosure is shown. Figure 5b This diagram illustrates the sensor mounting position in the vertical projection of the carrier provided in this disclosure. Figures 6a-6h Show each Figure 5a The diagram shows the distribution of the second detection unit in the carrier in various embodiments.

[0084] refer to Figure 5a This disclosure provides a carrier-based angular resolution measurement device 10 for static targets, which can be applied in applications such as reversing assistance, parallel parking, and map building. The angular resolution measurement device 10 is mounted on a carrier; in the following embodiments, the carrier can be a vehicle. The angular resolution measurement device 10 may include a sensor 110 and a processor 120. Combination Figure 4a and Figure 4b The sensor 110 is used to acquire the real-time vehicle speed V of the carrier, and to detect the radial velocity Vr of the static target 20 relative to the frequency-modulated continuous wave radar using frequency-modulated continuous wave radar. The processor 120 is communicatively connected to the sensor 110 and is used to calculate the horizontal angle θ of the static target 20 relative to the frequency modulated continuous wave radar based on the aforementioned real-time vehicle speed V and radial speed Vr.

[0085] In some optional embodiments, sensor 110 may include a first detection unit 111 and a second detection unit 112. The first detection unit 111 is used to communicatively connect to the vehicle's control system to acquire the vehicle's electronic control parameters and / or attitude detection parameters. The second detection unit 112 is used to transmit frequency-modulated continuous wave signals sequentially using a transmitting antenna (Tx) disposed on the second detection unit 112, and to receive echo signals reflected by static targets through a receiving antenna (Rx) disposed on the second detection unit 112. Figure 6a As shown, using vertically arranged on the side of the vehicle (e.g.) Figure 5b A single transmitting antenna at any of the marked positions 1, 3, 4, 5, 7 and 8 in the diagram sequentially transmits frequency-modulated continuous wave signals, and a single receiving antenna arranged vertically on the side of the vehicle receives the echo signals reflected by the static target 20.

[0086] Optionally, this arrangement of one transmitting and one receiving antenna can also reduce the measurement deviation caused by the height of the object by compressing the field of view (Fov) of the vertical antenna, and can also obtain horizontal orientation sensing by artificially setting a distance difference (installed on the side of the vehicle) to avoid the position of the horizontal axis. The antenna arrangement will not affect the measurement results of the angular resolution.

[0087] refer to Figure 5b In some optional embodiments, the location where the frequency-modulated continuous wave radar can be installed on the angle resolution measuring device 10 is marked, wherein the direction extending along the central axis is the vehicle's direction of travel. For example, in this embodiment and below, positions 1, 2, and 3 represent the front of the vehicle, and positions 5, 6, and 7 represent the rear of the vehicle, to facilitate a clear description of the radar installation location in subsequent embodiments. Of course, in other alternative embodiments, the represented direction can be opposite to the above direction, and this is not limited here.

[0088] In some alternative embodiments, the second detection unit 112 may be mounted on the side of the vehicle (e.g., Figure 5b The markers 1, 3, 4, 5, 7, and 8 in the diagram are used to detect targets on both sides of the vehicle. The aforementioned transmitting antenna (Tx) is a single, vertically arranged transmitting antenna, and the aforementioned receiving antenna (Rx) is a horizontally arranged receiving antenna array. Figure 6d As shown, or, the aforementioned transmitting antenna (Tx) is a horizontally arranged transmitting antenna array, and the aforementioned receiving antenna (Rx) is a single vertically arranged receiving antenna, such as... Figure 6e As shown. The angle θ calculated by the processor 120 is the angle of the static target 20 relative to the frequency-modulated continuous wave radar (or the angle resolution measuring device 10) at its ( Figure 4a(As shown) Azimuth angle information in the horizontal plane.

[0089] Optionally, if the transmitting antenna (Tx) and / or receiving antenna (Rx) are installed in the forward direction (marked positions 2 or 6), the ability to determine whether the angle is deviated to the left or right is required. This ability can be obtained by two or more transmitting or receiving antennas distributed in the horizontal direction.

[0090] In some alternative embodiments, the second detection unit 112 is mounted at any marked location on the vehicle (e.g., Figure 5b (any of the marked positions 1 to 8 in the above), and the aforementioned transmitting antenna (Tx) is a vertically arranged transmitting antenna array, and the aforementioned receiving antenna (Rx) is a horizontally arranged receiving antenna array, such as Figure 6f As shown, or, the aforementioned transmitting antenna (Tx) is a horizontally arranged transmitting antenna array, and the aforementioned receiving antenna (Rx) is a vertically arranged receiving antenna array, such as... Figure 6g As shown. The angle θ calculated by the processor 120 is the angle of the static target 20 relative to the frequency-modulated continuous wave radar (or the angle resolution measuring device 10) at its ( Figure 4a (As shown) Azimuth angle information in the horizontal plane.

[0091] Optionally, two or more vertically distributed antennas can be used, providing vertical angle estimation capabilities. This allows for horizontal angle compensation using the estimated object height (elevation angle). In this method, the accuracy of the height measurement will affect the accuracy of the final horizontal angle. Vertical elevation angle estimation capabilities (such as...) Figure 4b The scenario shown can be obtained by a receiving antenna or by a transmitting antenna in the form of MIMO.

[0092] In some alternative embodiments, the second detection unit 112 is mounted on the side of the vehicle (e.g., Figure 5b (any of the marked positions 1, 3, 4, 5, 7, and 8 in the above), and the aforementioned transmitting antenna (Tx) is a single transmitting antenna or an array of transmitting antennas arranged vertically, and the aforementioned receiving antenna (Rx) is an array of receiving antennas arranged vertically, such as Figure 6b and Figure 6f As shown, or, the aforementioned transmitting antenna (Tx) is a vertically arranged transmitting antenna array, and the aforementioned receiving antenna (Rx) is a single vertical receiving antenna or a receiving antenna array, such as... Figure 6c and Figure 6g As shown. The angle calculated by the processor 120 includes: the static target 20 relative to the frequency modulated continuous wave radar (or the angle resolution measuring device 10) at its ( Figure 4aThe processor 120 provides azimuth angle information in the horizontal plane (as shown) and elevation angle information β of the static target 20 measured by frequency-modulated continuous wave radar. Furthermore, the processor 120 is also used to perform phase compensation on the azimuth angle information θ of the static target 20 in the horizontal plane based on the elevation angle information β.

[0093] In some alternative embodiments, the second detection unit 112 is mounted at any marked location on the vehicle (e.g., Figure 5b (any of the marked positions 1 to 8 in the above), and the aforementioned transmitting antenna (Tx) is a transmitting antenna array, and the aforementioned receiving antenna (Rx) is a receiving antenna array, such as Figure 6h As shown, the angle calculated by the processor 120 includes: the static target 20 relative to the frequency modulated continuous wave radar (or the angle resolution measuring device 10) at its ( Figure 4a The processor 120 provides azimuth angle information in the horizontal plane (as shown) and elevation angle information β of the static target 20 measured by frequency-modulated continuous wave radar. Furthermore, the processor 120 is also used to perform phase compensation on the azimuth angle information θ of the static target 20 in the horizontal plane based on the elevation angle information β.

[0094] In some alternative embodiments, the frequency-modulated continuous wave signal is a millimeter-wave signal, and / or the sensor is a millimeter-wave chip.

[0095] In some alternative embodiments, the angular resolution measuring device 10 may acquire the real-time vehicle speed V while the vehicle is in motion by acquiring the real-time vehicle speed V based on the vehicle's ECU bus.

[0096] In some alternative embodiments, the angular resolution measuring device 10 may acquire the real-time vehicle speed V while the vehicle is traveling by acquiring the vehicle's first speed data in its direction of travel based on the vehicle's ECU bus. Acquire the second velocity data output by the vehicle's IMU; The real-time driving speed V of the vehicle is obtained by mixing and filtering the first speed data and the second speed data.

[0097] In some alternative embodiments, the angular resolution measuring device 10 may acquire the real-time vehicle speed V while the vehicle is traveling by acquiring the vehicle's first speed data in its direction of travel based on the vehicle's ECU bus. Acquire the second velocity data output by the vehicle's IMU; The third speed data is obtained by mixing and filtering the first and second speed data; The fourth velocity data of the vehicle is obtained by performing a two-dimensional Fourier transform on the velocity vector of the static target 20 relative to the frequency-modulated continuous wave radar; and The third speed data and the fourth speed data are mixed and filtered to obtain the vehicle's real-time driving speed V.

[0098] When only a static target 20 is observed, the radial velocity Vr of the static target 20 relative to the angle resolution measuring device 10 is generally less than or equal to the vehicle speed V. When the vehicle speed V is the maximum measurable speed Vm, the maximum angle resolution can be obtained. This solves the velocity ambiguity problem caused by MIMO in frequency-modulated continuous wave radar and improves the accuracy of angle measurement within the speed measurement range.

[0099] In this embodiment, the angular resolution obtained using the aforementioned angular resolution measuring device 10 is equivalent to the Doppler resolution, which allows for optimal angular resolution when the maximum unambiguous vehicle speed equals the vehicle's own speed. Therefore, at the beginning of each frame, the maximum unambiguous vehicle speed and the vehicle's own speed can be matched by adjusting the chirp period using the vehicle's own speed V, further improving the accuracy of angle measurement within the speed measurement range.

[0100] In summary, the carrier-based angular resolution measurement device 10 provided in this embodiment can effectively utilize Doppler FFT to calculate the equivalent horizontal angle, achieving high-resolution angular dimension measurement at a cost far lower than that of large-aperture MIMO in the prior art, without sacrificing the high angular resolution characteristics brought by MIMO, thus greatly expanding the applicability of this technology in the field of automotive radar.

[0101] Figure 7a The flowchart of the angle resolution measurement method based on frequency-modulated continuous wave radar provided in this disclosure is shown. Figure 7b Based on Figure 7a The diagram illustrates a parking scenario using the method described above. Figure 7c Based on Figures 7a-7b The diagram illustrates how the method obtains angle information in a given scenario. Figures 8-10 Show each Figure 7a The diagram shows a model of the angular resolution measurement method in different application scenarios. Figure 11 Show Figures 8-10 A schematic diagram of one of the models in a further implementation. Figure 12 Show Figures 8-10 A schematic diagram of one of the models in a further implementation.

[0102] refer to Figure 7a This disclosure provides a method for measuring angular resolution based on frequency-modulated continuous wave radar. In this embodiment, the carrier is a vehicle, and the angular resolution measurement method includes: Step S110: Install the frequency modulated continuous wave radar on the vehicle.

[0103] refer to Figure 5b In some optional embodiments, the angular resolution measuring device 10 marks the locations where the frequency-modulated continuous wave radar can be installed, with the direction extending along the central axis representing the vehicle's direction of travel. For example, in this embodiment and below, positions 1, 2, and 3 represent the front of the vehicle, and positions 5, 6, and 7 represent the rear of the vehicle, to facilitate a clear description of the radar installation location in subsequent embodiments. Of course, in other alternative embodiments, the represented directions can be opposite to those described above, and this is not a limitation.

[0104] As described in the first embodiment above, frequency-modulated continuous wave signals can be transmitted sequentially using the transmitting antenna (Tx) provided on the second detection unit 112, and the echo signals reflected by the static target can be received by the receiving antenna (Rx) provided on the second detection unit 112 respectively. Then, the processor 120 calculates the angle θ of the static target 20 relative to the frequency-modulated continuous wave radar based on the real-time vehicle speed V and radial speed Vr.

[0105] In step S110, the selection of the installation location of the frequency-modulated continuous wave radar on the vehicle can be set based on various methods described in the foregoing embodiments. Specifically: such as... Figure 6a As shown, the second detection unit 112 is installed on the side of the vehicle (e.g., Figure 5b (any of the marked positions 1, 3, 4, 5, 7, and 8 in the diagram). This arrangement of one transmitting and one receiving antenna, due to the lack of height estimation capability and horizontal distance difference sensing capability, requires compressing the vertical field of view to avoid measurement deviations caused by excessively tall objects. In addition, to avoid positions along the horizontal axis, a distance difference is artificially set (installed on the side of the vehicle) to obtain horizontal orientation sensing. The antenna arrangement does not affect the angular resolution measurement results.

[0106] Alternatively, in an optional embodiment, the second detection unit 112 is mounted on the side of the vehicle (e.g., Figure 5b (any of the marked positions 1, 3, 4, 5, 7, and 8 in the text), and setting the transmitting antenna (Tx) as a single transmitting antenna arranged vertically, and the receiving antenna (Rx) as a receiving antenna array arranged horizontally, as shown in the text. Figure 6d As shown, alternatively, the transmitting antenna (Tx) can be configured as a horizontally arranged transmitting antenna array, and the receiving antenna (Rx) can be configured as a single vertically arranged receiving antenna, as shown. Figure 6e As shown. When the transmitting antenna (Tx) and / or receiving antenna (Rx) are installed facing forward (as marked at position 2 or 6), the system needs to be able to determine whether the angle is deviated to the left or right. This capability can be achieved by two or more transmitting or receiving antennas distributed horizontally. Figure 6d and Figure 6e ‍) to obtain.

[0107] Alternatively, by using two or more vertically distributed antennas, vertical angle estimation capability can be achieved, enabling compensation of the horizontal angle using the estimated object height (pitch angle). In an optional embodiment, the second detection unit 112 is installed at any marked location on the vehicle (e.g., Figure 5b (At any of the marked positions 1 to 8 in the diagram), the transmitting antenna (Tx) is set as a vertically arranged transmitting antenna array, and the receiving antenna (Rx) is set as a horizontally arranged receiving antenna array, as shown below. Figure 6f As shown. Alternatively, the transmitting antenna (Tx) can be configured as a horizontally arranged transmitting antenna array, and the receiving antenna (Rx) as a vertically arranged receiving antenna array, as shown. Figure 6g As shown. Alternatively, the transmitting antenna (Tx) can be configured as a single transmitting antenna arranged vertically, and the receiving antenna (Rx) as a vertically arranged array of receiving antennas, as shown. Figure 6b As shown, alternatively, the transmitting antenna (Tx) can be configured as a vertically arranged transmitting antenna array, and the receiving antenna (Rx) can be a single vertically arranged receiving antenna, as shown. Figure 6b As shown. In this method, the accuracy of the height measurement will affect the accuracy of the final horizontal angle. The ability to estimate the vertical pitch angle (such as...) Figure 4b The scenario shown can be obtained by a receiving antenna or by a transmitting antenna in the form of MIMO.

[0108] Optionally, the aforementioned transmitting antenna (Tx) can be configured as a transmitting antenna array, and the aforementioned receiving antenna (Rx) can be configured as a receiving antenna array, such as... Figure 6h As shown, the angle calculated by the processor 120 includes: the static target 20 relative to the frequency-modulated continuous wave radar (or the angle resolution measuring device 10) at its ( Figure 4a As shown, the azimuth angle information in the horizontal plane, and the elevation angle information β of the static target 20 measured by the frequency-modulated continuous wave radar. Figure 4b (As shown). The processor 120 can then be used to: perform phase compensation on the azimuth angle information θ in the horizontal plane based on the pitch angle information β of the static target 20, so as to improve the accuracy of the high-resolution angular dimension measurement.

[0109] Step S120: Obtain the real-time driving speed of the vehicle while it is in motion.

[0110] In some alternative embodiments, the angular resolution measuring device 10 may acquire the real-time vehicle speed V while the vehicle is in motion by acquiring the real-time vehicle speed V based on the vehicle's ECU bus.

[0111] In some alternative embodiments, the angular resolution measuring device 10 may acquire the real-time vehicle speed V while the vehicle is traveling by acquiring the vehicle's first speed data in its direction of travel based on the vehicle's ECU bus. Acquire the second speed data output by the vehicle's IMU; The real-time driving speed V of the vehicle is obtained by mixing and filtering the first speed data and the second speed data.

[0112] In some alternative embodiments, the angular resolution measuring device 10 may acquire the real-time vehicle speed V while the vehicle is traveling by acquiring the vehicle's first speed data in its direction of travel based on the vehicle's ECU bus. Acquire the second velocity data output by the vehicle's IMU; The third speed data is obtained by mixing and filtering the first and second speed data; The fourth velocity data of the vehicle is obtained by performing a two-dimensional Fourier transform on the velocity vector of the static target 20 relative to the frequency-modulated continuous wave radar; and The third speed data and the fourth speed data are mixed and filtered to obtain the vehicle's real-time driving speed V.

[0113] Step S130: Use frequency modulated continuous wave radar to detect the radial velocity of a static target relative to the frequency modulated continuous wave radar.

[0114] In step S130, the step of detecting the radial velocity of a static target relative to the frequency-modulated continuous wave radar using a frequency-modulated continuous wave radar may specifically include: Obtain the distance of a static target relative to the frequency-modulated continuous wave radar; Obtain the velocity vector of the static target relative to the frequency-modulated continuous wave radar; and The aforementioned radial velocity is calculated based on the distance and velocity vectors.

[0115] The angular resolution measurement method for obtaining the distance of a static target relative to the frequency-modulated continuous wave radar may further include: preprocessing the frequency-modulated continuous wave signal before transmitting the signal, wherein the preprocessing includes matched filtering and / or Decirp processing.

[0116] When processing linear frequency modulated (chirp) signals, there are generally two methods: matched filtering and dechirp (frequency reduction). Matched filtering involves performing an FFT on the signal, multiplying it by the filter coefficients corresponding to the signal's signal form, and then performing an Inverse Fast Fourier Transform (IFFT) to obtain the waveform of the echo amplitude along the distance distribution. Matched filtering is generally performed in the digital domain, i.e., after analog-to-digital conversion. Dechirp processing involves mixing the received echo signal with the conjugate of the transmitted signal at the antenna's RF end, converting the target's distance relative to the radar from a time-dependent relationship to different frequencies. Then, after sampling with an ADC and performing an FFT, the target echo amplitude curve along the distance is obtained. The frequency values ​​corresponding to the peaks in the spectrum are then extracted and converted into the static target's distance relative to the frequency-modulated continuous wave radar using a formula.

[0117] In this embodiment, the velocity vector of the static target relative to the frequency-modulated continuous wave radar needs to be determined in conjunction with the installation method of the aforementioned frequency-modulated continuous wave radar antenna. When there is only horizontal measurement data, and when there is not only horizontal measurement data but also vertical measurement data, the velocity vector of the static target 20 relative to the frequency-modulated continuous wave radar is obtained through signal processing of the frequency-modulated continuous wave signal and the echo signal.

[0118] Step S140: Calculate the angle of the static target relative to the frequency modulated continuous wave radar based on the real-time vehicle speed and radial speed.

[0119] In step S140, the step of calculating the angle of the static target relative to the frequency-modulated continuous wave radar based on the real-time vehicle speed and radial velocity includes: The radial velocity is processed sequentially in the range dimension and the Doppler dimension to obtain corresponding signal data, and the angle of the static target relative to the frequency-modulated continuous wave radar is determined based on the signal data. The data processing includes operations including FFT processing, non-coherent accumulation and / or CFAR processing.

[0120] In some alternative embodiments, when only horizontal measurement data is available, the angle of the static target 20 relative to the frequency-modulated continuous wave radar includes the azimuth angle information of the static target 20 relative to the frequency-modulated continuous wave radar in its horizontal plane.

[0121] In some optional embodiments, when both horizontal and vertical measurement data are available, the angle of the static target 20 relative to the frequency-modulated continuous wave radar includes the azimuth angle information of the static target 20 relative to the frequency-modulated continuous wave radar in its horizontal plane, and the elevation angle information of the static target relative to the frequency-modulated continuous wave radar. Furthermore, the step of calculating the angle of the static target relative to the frequency-modulated continuous wave radar based on the real-time vehicle speed and radial speed further includes: Phase compensation is performed on the azimuth angle information of the static target in the horizontal plane using the measured pitch angle information.

[0122] Combination Figure 8 and Figure 6a ,use Figure 6a Antennas of this type, according to their corresponding side mounting method, based on Figure 8 The process model employs the frequency-modulated continuous wave radar to detect the radial velocity of a static target relative to the radar. This radial velocity is then processed sequentially in both the range and Doppler dimensions to obtain corresponding signal data. The horizontal azimuth angle is then calculated based on the real-time vehicle speed and the processed signal data to obtain the range-angle measurement result. Specifically, in calculating the radial velocity, the echo signal is first received via the radar receiving antenna. This echo signal is then converted to a digital signal using an ADC. The signal is then sampled using an ADC at a sampling rate greater than twice the maximum intermediate frequency signal frequency. After sampling, range-dimensional FFT and velocity-dimensional FFT operations are performed sequentially to extract the frequency values ​​corresponding to the peaks in the spectrum. These values ​​are then converted to the desired result using a formula. The two-dimensional Fourier transform calculation is used to obtain high resolution in the angle dimension. An angle information is extracted from the range-Doppler points using an angle measurement algorithm (Doppler-FFT requires a large number of points). Finally, the entire range-Doppler spectrum is converted into a range-angle spectrum. If the detection points are screened using CFAR (CFAR is an optional step), the workload afterward can be reduced.

[0123] The above calculation method requires knowledge of the vehicle's real-time speed V, which is in... Figure 8 The illustrated process model obtains the initial speed data from the vehicle's ECU via the CAN bus, processes it, and uses it as the vehicle's real-time driving speed V. For example... Figure 4a As shown, the angle between the static target 20 and the radar normal is θ. Therefore, its radial velocity Vr relative to the vehicle is: Vr = V / cos(θ). The radial velocity Vr is a known quantity after 2D-FFT calculation, and θ can be obtained through arccos calculation. By reordering the positions of the 2D-FFT results based on the calculation results, the range-angle image can be obtained.

[0124] Figure 7b The diagram illustrates the application of the frequency-modulated continuous wave radar-based angle resolution measurement method provided in this disclosure in a parking scenario. As the vehicle travels along a predetermined direction, sensors mounted on the side of the vehicle acquire horizontal azimuth angle information and distance information of nearby static targets (stationary vehicles). In this scenario, the vehicle's speed is assumed to be V. Using the sensor mounted on the vehicle as the base point, a scanning distance R is obtained at a specific range of angles (the angle θ from the vehicle scanned in the previous parking space in the normal direction and the angle β from the vehicle scanned in the next parking space in the normal direction) to determine whether there is a vehicle in the current parking space, thereby calculating the available parking spaces where vehicles can park.

[0125] exist Figure 7b In the parking scenario shown, according to Figure 7c The method for obtaining angle information shown is applied in applications such as... Figure 8 In the process model shown, assuming the normalized maximum speed is + / -Vm and the normalized maximum distance is Rm, if at a position at a distance R = Rm * 10 / 16, such as Figure 7c As shown, given the known real-time vehicle speed V = Vm * 7 / 8 and the radial velocity of the reflector (static target 20) relative to the vehicle Vr = Vm * 5 / 8, then according to the previous algorithm, the angle of the static target 20 is Ar = arccos(V / Vr) ≈ 45.6°. When only the static target 20 is observed, its radial velocity Vr relative to the angle resolution measuring device 10 is generally less than or equal to the vehicle speed V. When the vehicle speed V is the maximum measurable speed Vm, the maximum angle resolution can be obtained. This solves the speed ambiguity problem caused by MIMO in frequency-modulated continuous wave radar and improves the accuracy of angle measurement within the speed measurement range.

[0126] In some alternative embodiments, Figure 9 and Figure 10 The execution process of the process model shown is the same as that described above. Figure 8 The process model is similar, except that the method of obtaining the real-time driving speed V is different. This part can be understood in conjunction with the aforementioned embodiments, and will not be repeated here.

[0127] refer to Figure 11 The process model shown may introduce errors when there is a height difference between the reflective object and the radar in the application scenario. In this case, the following approach should be adopted: Figure 6b , Figure 6c and Figures 6f to 6hIn the antenna installation method described above, when both horizontal and vertical measurement data are obtained, the angle of the static target 20 relative to the frequency-modulated continuous wave radar includes: the azimuth angle information of the static target 20 relative to the frequency-modulated continuous wave radar in its horizontal plane, and the elevation angle information of the static target 20 relative to the frequency-modulated continuous wave radar. This necessitates using the measured elevation angle information of the static target 20 to perform phase compensation on its azimuth angle information in the horizontal plane, such as... Figure 4a and Figure 4b As shown, assuming the pitch angle is β and the azimuth angle is θ, when the vehicle's real-time speed is V, the radial velocity Vr = V*sin(θ)*cos(β). A large pitch angle β will lead to a large error. The pitch angle can be solved by using an antenna arranged in the pitch direction to compensate for the phase of the horizontal azimuth angle. When the pitch angle is known, the angle solution formula becomes Ar = arcsin(Vr / V / cos(β)) to further improve the accuracy of the angle dimension resolution measurement.

[0128] In this embodiment, when the frequency-modulated continuous wave radar is mounted on the front of the vehicle, ambiguity occurs when the absolute values ​​of the azimuth angles on the left and right sides of the radar are the same, making it impossible to determine whether the static target 20 is on the left or right. Therefore, when the radar antenna is mounted on the front, it must have horizontal angle estimation capability to determine whether the static target 20 is on the left or right side of the radar, i.e., it must be equipped with... Figures 6d to 6h The solution process for the horizontal antenna array is similar to the aforementioned process model. For details, please refer to the specific embodiments and process models for further understanding.

[0129] In some alternative embodiments, reference is made to Figure 12 The illustrated process model, after obtaining the real-time vehicle speed, further includes adjusting the initial frequency and duration of the frequency-modulated continuous wave signal. Since the angular resolution in this embodiment is equivalent to Doppler resolution, the optimal angular resolution can be obtained when the maximum unambiguous vehicle speed equals the vehicle speed (real-time speed in this context). Therefore, at the beginning of each frame, the real-time vehicle speed V can be used to adjust the chirp period to constrain the vehicle's maximum unambiguous vehicle speed Vm to match its real-time speed V. Other calculation procedures remain unchanged.

[0130] Therefore, the above-mentioned angle resolution measurement method can improve the accuracy of angle measurement within the speed measurement range without losing the high angle resolution characteristics brought by MIMO, which greatly expands the practicality of this technology in the field of automotive radar.

[0131] The method and apparatus for acquiring static target angle information based on a carrier disclosed herein simplify the amount of data acquisition and computation during the data measurement process through the installation design of the radar antenna. While ensuring the accuracy and precision of high-resolution angle measurement, it effectively reduces the computational load of the system, thereby reducing the system cost.

[0132] Furthermore, the method of using CFAR processing after processing the distance dimension and Doppler dimension avoids the traditional two-dimensional processing method of performing FFT on all distance cells while ensuring the detection rate. Therefore, it can effectively reduce the computational load of the system and thus reduce the system cost.

[0133] Furthermore, for different types of millimeter-wave radars, due to differences in parameters such as carrier frequency, bandwidth, frequency modulation slope, and frame length, the range Doppler RD map will show differences in parameters such as range resolution, maximum unambiguous range, velocity resolution, and maximum unambiguous velocity. In order to make the extracted measurement data more effective and robust, the radar parameters should be kept as consistent as possible during the measurement process.

[0134] The computer program product of the method for acquiring static target angle information based on a carrier provided in this disclosure includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the preceding method embodiments. For specific implementation details, please refer to the method embodiments, which will not be repeated here.

[0135] To further improve isolation and increase the ability to suppress leakage signals, the transmission and reception distance can be increased, and sufficient space can be left between the receiving antenna and the transmitting antenna to place devices that increase isolation.

[0136] This disclosure provides a method, apparatus, and SLAM system for acquiring angle information of a static target. The method includes: acquiring the travel speed of a sensor; acquiring Doppler data of the static target using the sensor; and acquiring the horizontal angle information of the static target relative to the sensor based on the travel speed and the Doppler data. This effectively utilizes Doppler FFT for equivalent angle calculation, achieving high-resolution angle measurement at a significantly lower cost than the large-aperture MIMO used in existing technologies. It solves the velocity ambiguity problem caused by MIMO in frequency-modulated continuous wave radar, improving the accuracy of angle measurement within the speed range without sacrificing the high angular resolution characteristics of MIMO, greatly expanding the practicality of this technology in the field of automotive radar.

[0137] Furthermore, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0138] It should be noted that, in the description of this disclosure, the terms "upper," "lower," "inner," etc., which indicate orientation or positional relationship, are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0139] Furthermore, throughout this document, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0140] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating this disclosure and are not intended to limit the implementation. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of this disclosure.

Claims

1. A device for acquiring angle information of a static target, characterized in that, include: An FMCW sensor is used to perform 2D-FFT on the received echo signal and then continue CFAR to obtain a range-Doppler spectrum, wherein the range-Doppler spectrum includes the Doppler data of the static target; The processor is configured to perform vector calculations based on the Doppler data and the travel speed of the FMCW sensor to convert the range-Doppler map into a range-angle map, thereby obtaining the horizontal angle information of the static target relative to the FMCW sensor.

2. The apparatus as claimed in claim 1, characterized in that, The vector calculation is based on the formula Vr=V / cos(θ) or Vr=V·sin(θ)·cos(β), where V is the travel speed, Vr is the radial speed, θ is the horizontal angle, and β is the pitch angle.

3. The apparatus as described in claim 1, characterized in that, Also includes: The sensor is fixedly mounted on the carrier. The travel speed output by the carrier is the travel speed of the sensor.

4. The apparatus according to any one of claims 1-3, characterized in that, The sensor includes a millimeter-wave radar chip. The processor is either an on-chip processing unit located within the millimeter-wave radar chip or an external processing unit on the carrier.

5. A device for acquiring angle information of a static target, characterized in that, include: The FMCW sensor is fixedly mounted on the carrier and is used to acquire Doppler data of static targets. as well as The processor is configured to acquire the horizontal angle information of the static target relative to the FMCW sensor based on the travel speed of the FMCW sensor and the Doppler data; In the direction of travel of the carrier, the FMCW sensor is mounted on the side of the carrier, and the FMCW sensor has at least one transmitting antenna and at least one receiving antenna, the total number of transmitting antennas and receiving antennas being less than 4.

6. The apparatus as claimed in claim 5, characterized in that, The processor is also used to compress the field of view of the signal received by the FMCW sensor in the vertical direction and then obtain the Doppler data of the static target.

7. A device for acquiring angle information of a static target, characterized in that, include: The FMCW sensor is fixedly mounted on the carrier and is used to acquire Doppler data of static targets. as well as The processor is configured to acquire the horizontal angle information of the static target relative to the FMCW sensor based on the travel speed of the FMCW sensor and the Doppler data; In the direction of travel of the carrier, the FMCW sensor is mounted on the side of the carrier, and the FMCW sensor has at least two transmitting antennas or at least two receiving antennas distributed in the vertical direction; the processor is also used to compensate for the horizontal angle information using the height value of the static target obtained by the FMCW sensor.

8. A device for acquiring angle information of a static target, characterized in that, include: The FMCW sensor is fixedly mounted on the carrier and is used to acquire Doppler data of static targets. as well as The processor is configured to acquire the horizontal angle information of the static target relative to the FMCW sensor based on the travel speed of the FMCW sensor and the Doppler data; In the direction of travel of the carrier, the FMCW sensor is installed on the front or back of the carrier, and the FMCW sensor has at least two transmitting antennas or at least two receiving antennas distributed in the horizontal direction; the processor is also used to determine whether the static target is to the left or right of the FMCW sensor based on the detection results of the at least two transmitting antennas or at least two receiving antennas distributed in the horizontal direction.

9. A method for acquiring angle information of a static target, applied to a moving FMCW sensor, characterized in that, include: The travel speed of the sensor is obtained; A two-dimensional fast Fourier transform is performed on the echo signal received by the sensor to obtain the entire range-Doppler spectrum; The entire range-Doppler spectrum is directly converted into a range-angle spectrum without constant false alarm rate processing to obtain high-precision angle information for each static target; as well as The horizontal angle information of the static target relative to the sensor is obtained based on the travel speed and the distance-angle map.

10. A method for obtaining angle information of a static target, characterized in that, An FMCW sensor used in motion, the sensor being fixedly mounted on a carrier, the method comprising: Obtain the real-time speed of the carrier; The speed is obtained from the inertial motion velocimetry device installed on the carrier; The velocity obtained by the inertial motion velocimetry device is fused with the real-time travel velocity using a filter to obtain the fused travel velocity; The Doppler data of the static target are acquired using the sensor; and The horizontal angle information of the static target relative to the sensor is obtained based on the fused travel speed and the Doppler data.

11. A real-time positioning and mapping system, characterized in that, The system includes the apparatus as described in any one of claims 1-8, wherein the system is configured to acquire horizontal angle information of the static target relative to the sensor and perform real-time positioning and / or map building.

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