A system and method for improving the angle measurement accuracy of vehicle-mounted millimeter-wave radar

Abstract

The present invention discloses a system and method for improving the angle measurement accuracy of a vehicle-mounted millimeter-wave radar, belonging to the technical field of vehicle-mounted radars. The system comprises a vehicle-mounted millimeter-wave radar, a gyroscope sensor and a signal processor; the vehicle-mounted millimeter-wave radar is operated to sense target obstacles around a vehicle; wherein the vehicle-mounted millimeter-wave radar has a transmitting antenna and two receiving antennas, and the distance between the two receiving antennas is d; the gyroscope sensor is operated to obtain the current tilt angle α of the vehicle-mounted millimeter-wave radar in the forward direction of the vehicle; the signal processor is operated to receive the sensing information of the vehicle-mounted millimeter-wave radar and the current tilt angle α of the vehicle-mounted millimeter-wave radar, and calculate the projection distance d between the two receiving antennas of the vehicle-mounted millimeter-wave radar based on the information. ， , and then obtain the angle θ of the target obstacle. The system and method of the present invention can improve the angle measurement accuracy of the vehicle-mounted millimeter wave radar installed in the vehicle when the vehicle is tilted.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle-mounted radars, and in particular relates to a system and method for improving the angle measurement accuracy of a vehicle-mounted millimeter-wave radar. Background Art

[0002] Millimeter-wave radar is one of the key sensors in ADAS. The main function of millimeter-wave radar is to sense surrounding obstacles and provide information such as the distance, angle, Doppler speed, etc. of the obstacles. For general 3D millimeter-wave radar, the angle information mainly refers to the azimuth information, while for 4D millimeter-wave radar, it includes both azimuth and pitch angle information.

[0003] Therefore, the accuracy of the output obstacle (target) distance, angle, and Doppler velocity parameters is the key to measuring the performance of millimeter-wave radar.

[0004] The angle is usually measured using the phase difference method, as shown in the attached Figure 1 As shown:

[0005] In the figure, it is assumed that the radar has one transmitting antenna (the transmitting antenna is not shown in the figure) and two receiving antennas (in order to improve the angle measurement accuracy and resolution, more than two receiving antennas will be used, and more than one transmitting antenna may be used to form MIMO and increase the number of virtual receiving antennas). The electromagnetic waves emitted by the transmitting antenna are reflected by the target and reach the receiving antenna. The far field is usually considered, that is, when the target is large enough relative to the antenna spacing d, the electromagnetic waves received by different receiving antennas are approximately parallel. In this way, the following relationship exists:

[0006]

[0007] in, is the phase difference of the signals received by the two receiving antennas, which can usually be calculated by subsequent signal processing. λ is the wavelength of the electromagnetic wave, which is known. And d is a known design value. In this way, the angle of the target can be calculated:

[0008]

[0009] The above principle assumes that the antenna array is arranged in the same plane as the target to be measured. However, in actual use, millimeter-wave radar will inevitably encounter uneven ground or tilted vehicles. Figure 2 The corresponding radar status is shown in the attached Figure 3 As shown. In this case, the measured antenna spacing d' under the target angle plane is inconsistent with the design value d, but presents a projection relationship: d' = dcosα. Where α is the tilt angle. When α = 0, that is, no tilt, d' = d, and directly using the design value d will not cause errors. When α≠0, directly using the design value d will cause errors.

[0010] To this end, we propose a system and method for improving the angle measurement accuracy of vehicle-mounted millimeter-wave radar to solve the above-mentioned problems. Summary of the invention

[0011] The purpose of the present invention is to provide a system and method for improving the angle measurement accuracy of vehicle-mounted millimeter-wave radar, so as to solve the problems raised in the above-mentioned background technology.

[0012] To achieve the above object, according to one aspect of the present invention, the present invention provides a system for improving the angle measurement accuracy of a vehicle-mounted millimeter-wave radar, the system comprising a vehicle-mounted millimeter-wave radar, a gyroscope sensor and a signal processor;

[0013] The vehicle-mounted millimeter-wave radar operates to sense target obstacles around the vehicle and provide distance, angle and Doppler velocity information of the target obstacles;

[0014] The vehicle-mounted millimeter-wave radar has a transmitting antenna and two receiving antennas, and the distance between the two receiving antennas is d;

[0015] The gyroscope sensor is operated to obtain the current tilt angle α of the vehicle-mounted millimeter-wave radar in the forward direction of the vehicle;

[0016] A signal processor is connected to the gyro sensor and the vehicle-mounted millimeter-wave radar, and is operated to receive the sensing information of the vehicle-mounted millimeter-wave radar and the current tilt angle α of the vehicle-mounted millimeter-wave radar, thereby calculating the projection distance d' between the two receiving antennas of the vehicle-mounted millimeter-wave radar, and then obtaining the angle θ of the target obstacle;

[0017] d'=dcosα (1)

[0018]

[0019] Wherein, is the phase difference of the signals received by the two receiving antennas, which is calculated through subsequent signal processing, is the known wavelength of the electromagnetic wave, and d is the known design value of the spacing between the two receiving antennas, and θ is the angle of the target obstacle calculated.

[0020] Preferably, when the vehicle is driving steadily on a smooth road, the gyro sensor obtains the current tilt angle α=0 of the on-board millimeter-wave radar of the vehicle.

[0021] Preferably, the value of the tilt angle α is the angular velocity of the gyro sensor rotating in the forward direction of the vehicle, and is obtained by integrating time.

[0022] In another aspect of the present invention, the present invention provides a method for improving the angle measurement accuracy of a vehicle-mounted millimeter-wave radar, which specifically includes the following steps:

[0023] 1) When the vehicle equipped with the vehicle-mounted millimeter-wave radar is driving steadily on a smooth road, the tilt angle α=0;

[0024] 2) When the vehicle encounters an uneven ground or tilts, the gyroscope sensor obtains the current tilt angle α≠0 of the vehicle's onboard millimeter-wave radar in the forward direction;

[0025] 3) d'=dcosα is used to calculate the projection distance between the two receiving antennas of the vehicle-mounted millimeter-wave radar, and then the projection distance d' is used to measure the angle of the target obstacle, thereby obtaining the angle θ of the target obstacle.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention uses a gyro sensor in conjunction with a vehicle-mounted millimeter-wave radar to measure a target obstacle in the forward direction of the vehicle, so that the angle measurement accuracy of the vehicle-mounted millimeter-wave radar installed on the vehicle can be improved when the vehicle is tilted. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the phase difference angle measurement principle of the vehicle-mounted millimeter wave radar;

[0029] Figure 2 Schematic diagram of the deflection of a normally moving car (left) and a tilted car (right);

[0030] Figure 3 Schematic diagram of the vehicle-mounted millimeter-wave radar deflection of a normally moving vehicle (left) and a tilted vehicle (right);

[0031] Figure 4 The present invention is a flowchart of a method for improving the angle measurement accuracy of vehicle-mounted millimeter-wave radar. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The vehicle-mounted millimeter-wave radar of the present invention has one transmitting antenna and two receiving antennas (in order to improve the angle measurement accuracy and resolution, more than two receiving antennas will be used, and more than one transmitting antenna may be used to form MIMO to increase the number of virtual receiving antennas). The electromagnetic waves emitted by the transmitting antenna are reflected by the target and reach the receiving antenna. The far field is usually considered, that is, when the target is large enough relative to the antenna spacing d, the electromagnetic waves received by different receiving antennas are approximately parallel. In this way, the following relationship exists:

[0034]

[0035] in, is the phase difference of the signals received by the two receiving antennas, which can usually be calculated by subsequent signal processing, λ is the known wavelength of the electromagnetic wave, and d is the known design value of the distance between the two receiving antennas.

[0036] As an embodiment of the present invention, see Figure 1-3 The present invention provides a system for improving the angle measurement accuracy of a vehicle-mounted millimeter-wave radar, which can improve the angle measurement accuracy of a vehicle-mounted millimeter-wave radar installed on a vehicle when the vehicle is tilted. The system includes a vehicle-mounted millimeter-wave radar, a gyroscope sensor, and a signal processor;

[0037] The vehicle-mounted millimeter-wave radar operates to sense target obstacles around the vehicle and provide distance, angle and Doppler velocity information of the target obstacles;

[0038] The vehicle-mounted millimeter-wave radar has a transmitting antenna and two receiving antennas, and the distance between the two receiving antennas is d;

[0039] The gyroscope sensor is operated to obtain the current tilt angle α of the vehicle-mounted millimeter-wave radar in the forward direction of the vehicle;

[0040] A signal processor is connected to the gyro sensor and the vehicle-mounted millimeter-wave radar, and is operated to receive the sensing information of the vehicle-mounted millimeter-wave radar and the current tilt angle α of the vehicle-mounted millimeter-wave radar, thereby calculating the projection distance d' between the two receiving antennas of the vehicle-mounted millimeter-wave radar, and then obtaining the angle θ of the target obstacle;

[0041] d'=dcosα (1)

[0042]

[0043] Wherein, is the phase difference of the signals received by the two receiving antennas, which is calculated through subsequent signal processing, is the known wavelength of the electromagnetic wave, and d is the known design value of the spacing between the two receiving antennas, and θ is the angle of the target obstacle calculated.

[0044] In this embodiment, when the vehicle is driving steadily on a smooth road, the gyro sensor obtains the current tilt angle α=0 of the on-board millimeter-wave radar of the vehicle.

[0045] In this embodiment, the value of the tilt angle α is the angular velocity of the gyro sensor rotating in the forward direction of the vehicle, and is obtained by integrating time.

[0046] It should be noted that in the system of the present invention for improving the angular measurement accuracy of the vehicle-mounted millimeter-wave radar, the IMU can also be used to replace the gyroscope sensor. Since the IMU contains a gyroscope module, the inclination angle α of the vehicle and the vehicle-mounted millimeter-wave radar can be obtained when the vehicle is tilted, and d'=dcosα is used to calculate the projection distance between the two receiving antennas of the vehicle-mounted millimeter-wave radar, and then the projection distance d' is used to measure the angle of the target obstacle, and then the angle θ of the target obstacle is obtained, thereby finally improving the angular measurement accuracy of the vehicle-mounted millimeter-wave radar installed on the vehicle.

[0047] As another embodiment of the present invention, see Figure 4 The present invention provides a method for improving the angle measurement accuracy of a vehicle-mounted millimeter-wave radar, which specifically comprises the following steps:

[0048] 1) When the vehicle equipped with the vehicle-mounted millimeter-wave radar is driving steadily on a smooth road, the tilt angle α=0;

[0049] 2) When the vehicle encounters an uneven ground or tilts, the gyroscope sensor obtains the current tilt angle α≠0 of the vehicle's onboard millimeter-wave radar in the forward direction;

[0050] 3) d'=dcosα is used to calculate the projection distance between the two receiving antennas of the vehicle-mounted millimeter-wave radar, and then the projection distance d' is used to measure the angle of the target obstacle, thereby obtaining the angle θ of the target obstacle.

[0051] Specifically, a signal processor is used to receive the current tilt angle α of the vehicle-mounted millimeter-wave radar in the forward direction of the vehicle obtained by the gyroscope sensor, and the projection distance d' between the two receiving antennas of the vehicle-mounted millimeter-wave radar is calculated by d'=dcosα, thereby improving the angle measurement accuracy of the vehicle-mounted millimeter-wave radar installed on the vehicle to the target obstacle.

[0052] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0053] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A system for improving the angle measurement accuracy of vehicle-mounted millimeter-wave radar, characterized in that: The system includes an on-board millimeter-wave radar, a gyro sensor, and a signal processor; The vehicle-mounted millimeter-wave radar operates to sense target obstacles around the vehicle and provide distance, angle and Doppler velocity information of the target obstacles; The vehicle-mounted millimeter-wave radar has a transmitting antenna and two receiving antennas, and the distance between the two receiving antennas is d ; The gyroscope sensor is operated to obtain the current left-right tilt angle α of the vehicle-mounted millimeter-wave radar in the forward direction of the vehicle; The signal processor is connected to the gyro sensor and the vehicle-mounted millimeter-wave radar, and is operated to receive the sensing information of the vehicle-mounted millimeter-wave radar and the tilt angle α obtained by the gyro sensor, so as to calculate the projection distance between the two receiving antennas of the vehicle-mounted millimeter-wave radar. d ， , and then obtain the angle of the target obstacle θ ; （1） （2） In the formula, It is the phase difference of the signals received by the two receiving antennas, which is calculated through subsequent signal processing. , is the known wavelength of electromagnetic waves, and d is the known design value of the spacing between the two receiving antennas, θ To calculate the angle of the target obstacle; When the vehicle is running steadily on a smooth road, the gyro sensor obtains the tilt angle α=0; The value of the tilt angle α is the angular velocity of the gyro sensor rotating in the vehicle's forward direction, and is obtained by integrating time.

2. A method for improving the angle measurement accuracy of a vehicle-mounted millimeter-wave radar, applied to a system for improving the angle measurement accuracy of a vehicle-mounted millimeter-wave radar as claimed in claim 1, characterized in that: The specific steps include: 1) When the vehicle equipped with the vehicle-mounted millimeter-wave radar is driving steadily on a smooth road, at this time, the tilt angle α=0; 2) When the vehicle encounters an uneven ground or the vehicle tilts left or right, the gyroscope sensor obtains the tilt angle α≠0; 3) Use To calculate the projection distance between the two receiving antennas of the vehicle-mounted millimeter-wave radar, and then use the projection distance d ， Measure the angle of the target obstacle and obtain the angle of the target obstacle θ .

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