Vehicle radar sensor and method of operation

Abstract

The present disclosure relates to vehicle radar sensors and operating methods. A radar sensor (300) for use in a vehicle is described herein. The radar sensor includes: at least one transmitter (308) and at least one receiver (302) for transmitting and receiving radar signals of the radar sensor (300); an acceleration sensor (200) for measuring the acceleration of the radar sensor or the vehicle; a processor (320) coupled to the acceleration sensor (200) to calculate the tilt of the radar signal projected from the vehicle using the measured acceleration; and a memory (330) for storing the calculated radar tilt.

Description

Technical Field

[0001] The present invention relates to a radar system for use in a vehicle to measure and / or correct any tilt of the radar beam that may be caused by driving conditions. Background Art

[0002] The demand for active safety systems for vehicles is increasing. Active safety systems require multiple radar sensors per vehicle, each radar sensor typically working with a specific radar technology. In automotive applications, radar sensors are primarily built using multiple integrated circuits (ICs), sometimes referred to as 'chips'. The current trend is to provide a radar system on a chip (SOC, using radio frequency (RF) CMOS process technology) solution in order to reduce cost and power consumption.

[0003] Commercial automotive radar sensors typically include multiple receivers and transmitters (the combination of which is called a transceiver (TRX)) implemented as a phased array radar system to increase output power, receiver sensitivity, and angular resolution. A microcontroller (MCU) performs digital control of the transceiver circuit and performs digital signal processing (e.g., fast Fourier transform (FFT) and digital signal processing) on ​​the digitized data to output the processed radar data to the vehicle's central processing unit (CPU).

[0004] In addition, there are a few radar sensor technologies that are adopted and installed by leading vehicle manufacturers. Each of these technologies is different in the operating principle, and usually each radar sensor architecture (and associated radar technology) is supported by a dedicated IC group. It is known that radar systems with a large number of transceiver units configured to work in parallel provide better angle estimation accuracy and detection range. It is also known that radar customers want radar transceiver ICs that can support multi-chip cascading to enhance the accuracy of target positioning and path prediction of their systems.

[0005] Many vehicles today will use radar systems to provide information about surrounding conditions, detect other vehicles or pedestrians on the road, or other objects in the path the vehicle is traveling. Radar can also be used to detect the overall conditions of the road the vehicle is traveling. Figure 1As described. Generally, the radar is mounted on the front and / or rear of the vehicle 100 and is typically positioned perpendicularly relative to the direction of travel of the vehicle, and as the vehicle travels along the road 102 (the direction of travel is shown by arrow A), the radar will project a beam at a known angle. Assuming the vehicle is traveling on a flat surface and the vehicle 100 maintains a stable position as it travels along the road, the radar will have a standard known projection in front of the vehicle 104. When the rear of the vehicle is lower than the front (for example, if the rear of the vehicle is carrying a heavy object), the front of the vehicle will be higher than the rear, and therefore the radar at the front of the vehicle will have an upward tilt. Conversely, if the vehicle 100 brakes sharply, the front of the vehicle will tilt downward, and the radar at the front of the vehicle will have a downward tilt 106. For example, in some cases, if the vehicle is traveling along an uneven surface, the front of the vehicle will move up and down depending on the surface of the road, and the angle of the radar beam from the front of the vehicle will change as the surface of the road changes 108. These possible alternatives are described in detail in detail. Figure 1 Shown in.

[0006] like Figure 1 As shown, when the vehicle 100 brakes, the beam will tilt downward, and when the vehicle accelerates, it will tilt upward (not shown in the figure). Figure 1 As shown in Figure 1, when the vehicle is traveling over an uneven road surface, the beam may tilt up and down in any direction. Tilt will also vary depending on acceleration or braking speed, and may also be affected by vehicle size, tire springs, and other parameters related to the vehicle. However, these are not as large an effect of tilt as speed. These "vehicle" parameters may vary from vehicle to vehicle, for example, a more expensive vehicle may have a suspension that can compensate for uneven roads compared to a more basic vehicle.

[0007] There is a demand in the automotive industry for radar systems on vehicles to be able to perform elevation angle measurements with good resolution. Current systems typically have a resolution of 1°.

[0008] Vehicle movement while the vehicle is moving, for example due to road bumps, acceleration, braking, etc., may cause the tilt of the transmitted radar signal to change. This applies to ordinary vehicles with human drivers as well as autonomous vehicles. This may lead to large errors in the elevation measurement of the radar signal. Traveling large distances may also exacerbate this problem. A small tilt of the radar beam may lead to significant differences in the measured elevation angle, and this will increase with increasing distance. For example, a beam tilted 1.4 degrees at a distance of 200m will result in a difference of 5m in the measured altitude, while a beam tilted 2.8 degrees will produce the same 5m altitude difference, but at a distance of 100m. Summary of the invention

[0009] According to a first aspect of the present invention, there is provided a radar sensor for use in a vehicle, comprising:

[0010] at least one transmitter and at least one receiver for transmitting and receiving radar signals of the radar sensor;

[0011] an acceleration sensor, used to measure the acceleration of the radar sensor or the vehicle;

[0012] a processor coupled to the acceleration sensor to calculate a tilt of a radar signal projected from the vehicle using the measured acceleration;

[0013] a memory for storing the calculated radar tilt;

[0014] The sensor is capable of processing the measured acceleration and adjusting the tilt of the radar signal or classifying the measured data in response to the measured acceleration.

[0015] In one or more embodiments, the acceleration sensor is coupled to the transmitter of the radar sensor.

[0016] In one or more embodiments, the acceleration sensor measures the acceleration of the radar sensor in a direction that makes an angle between 30° and 150° with the direction of travel of the vehicle.

[0017] In one or more embodiments, the direction of the acceleration sensor makes an angle between 75° and 105° with the direction of travel.

[0018] In one or more embodiments, the radar sensor further includes a beam corrector, wherein the beam corrector compares the calculated radar tilt with a preset reference tilt, and if the difference between the preset value and the reference value exceeds a set threshold, adjusts the tilt to the preset value.

[0019] In one or more embodiments, the threshold is dynamically adjusted based on driving conditions.

[0020] In one or more embodiments, the beam corrector is a beam steering device or a phase rotator.

[0021] In one or more embodiments, the beam corrector is located within the at least one transmitter.

[0022] In one or more embodiments, the tilt of the radar signal is adjusted in the receiver via software control.

[0023] In one or more embodiments, the radar sensor further comprises a calibration unit for calibrating the radar signal.

[0024] In one or more embodiments, the calibration unit is located within the processor.

[0025] In one or more embodiments, the processor can process the classified data from the radar signal in conjunction with the calculated radar tilt.

[0026] According to a second aspect of the present invention, there is provided a method for adjusting a radar signal transmitted from a vehicle, comprising:

[0027] transmitting a radar signal from the vehicle;

[0028] measuring the acceleration of the vehicle;

[0029] calculating a tilt of the radar signal using the measured acceleration;

[0030] comparing the calculated tilt to a stored reference tilt;

[0031] If the comparison of the calculated tilt to the reference tilt exceeds a predetermined value, the tilt of the radar signal is adjusted.

[0032] In one or more embodiments, the radar signal is conditioned using a phase rotator.

[0033] In one or more embodiments, the radar signal is adjusted using software.

[0034] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The further details, aspects and embodiments of the present invention will be described by way of example only with reference to the drawings. In the drawings, the same reference numerals are used to identify elements that are identical or functionally similar. The elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale.

[0036] Figure 1 Examples illustrating radar signatures of vehicles travelling under different conditions;

[0037] Figure 2 Describe the acceleration sensor used in the present invention;

[0038] Figure 3 is an example of the radar device of the present invention;

[0039] Figure 4 is an alternative example of the radar device of the present invention;

[0040] Figure 5 is a flow chart illustrating the method of the present invention. DETAILED DESCRIPTION

[0041] Because the illustrated example embodiments of the present invention may be implemented, for the most part, using electronic components and circuits known to those skilled in the art, details will not be explained to any greater extent than is deemed necessary as shown below, for the sake of understanding and appreciation of the underlying concepts of the present invention and in order not to obscure or distract from the teachings of the present invention.

[0042] The inventors have recognized and appreciated that it is desirable to improve the resolution of radar devices. As automotive radar sensors evolve, they will be required to have higher resolution, for example, improved resolution may help determine whether a vehicle is likely to pass an obstacle in the road. The obstacle may be a speed bump, a gully, or a gutter cover. If an obstacle causes the radar beam to tilt toward the street due to vehicle braking or the presence of a hole in the road, this may cause the vehicle to, for example, perform emergency braking, or slow down the vehicle, which may affect the overall driving, or cause travel delays, especially for autonomous vehicles.

[0043] Using acceleration measurements and radar information to correct beam tilt or gain system information will result in improvements in overall system performance.

[0044] Figure 2 is an example of an acceleration sensor 200 that can be used in the present invention. The acceleration sensor 200 includes a voltage regulator 202, a programmable data array 204, a reference oscillator 206, a master oscillator 208, a clock monitor 210, an internal clock 212, a control logic 214, a serial peripheral interface (SPI) 216, a pulse code modulator (PCM) 218, a digital signal processor (DSP) 220, a temperature sensor 222, sinc filters 224 and 236, converters 226 and 234, ion photocells (g-cells) 228 and 232, and a self-test interface 230. In the example of the present invention, the acceleration sensor 200 measures the acceleration of the radar sensor on the vehicle in the vertical direction when the vehicle moves, but in some examples, the sensor can measure the acceleration of the radar sensor in other directions relative to the direction of vehicle movement. Generally speaking, the acceleration will be measured at an angle between 30° and 150° with the direction of vehicle travel, or more specifically, at an angle between 75° and 105°. In another preferred example of the present invention, the acceleration is measured in a direction substantially perpendicular to the vehicle's traveling direction. For example, the acceleration measurement of the radar sensor or the vehicle chassis in the vertical direction can be implemented based on the differential capacitance principle generated by the acceleration-induced motion of the radar sensor.

[0045] Figure 33 is an illustration of an example of a circuit implementing an example of the present invention, the circuit comprising a radar 300 sensor, an accelerometer 200, an automotive radar microcontroller 350, the automotive radar microcontroller 350 comprising a processor 320 and a memory 330. The processor 320 may also include a calibration unit 322. The radar sensor 300 comprises a receiver array 302, a receiver antenna 304, a transmitter array 308, the transmitter array comprising a beam corrector 360 (in the example of the present invention, the beam corrector may be a beam steering device or a phase rotator), a transmitter antenna 306, an output array 310, a chirp generator 312, an internal balun 314, an external balun 318, and a bypass 316. The accelerometer 200 is coupled to the automotive radar microcontroller 350. The radar sensor generates a radio frequency that is transmitted, reflected by an object, and then received via the RX antenna. The received signal is mixed to a lower frequency and digitized for further processing in the microcontroller.

[0046] In this example of the invention, this circuit uses beam corrector functionality to adjust and / or correct beam tilt errors in the beam emitted by the radar sensor caused by vehicle chassis movement. The calculated beam tilt of the sensor will be compared with a preset reference value of the beam tilt, and if the difference between the two measured values ​​exceeds a preset threshold, the beam tilt will be adjusted to the preset value to correct the beam tilt back to the desired value. In an embodiment of the present invention, the preset reference threshold can be set when the radar sensor is initially installed on the vehicle, or the preset reference threshold can be changed at any time depending on driving conditions or other external factors. In a phased array antenna setting, the measured acceleration value is used to adjust the tilt of the transmitted radar beam using the beam corrector 360. In the example of the present invention, the measured acceleration and the tilt angle will be a simple relationship, so that if the acceleration exceeds the value x, the radar beam is corrected to an angle y°. In the example of the present invention, the greater the acceleration, the greater the corrected tilt angle. In addition, this relationship will also take into account the delay of the radar beam.

[0047] Figure 4 A circuit is shown for an alternative method of correcting beam tilt. Figure 3 Like elements have been given like reference numbers. In this example of the invention, the circuit does not include a beam corrector, but rather uses software within the automotive radar microcontroller 350 to process information from the acceleration sensor 200 to calculate the beam tilt, and the microcontroller will communicate with the radar sensor 300 to correct the tilt of the radar beam based on a comparison with a threshold value.

[0048] In the examples of the present invention, Figure 3 and 4The circuit may be used to (i) correct the radar beam tilt based on the measured acceleration of the radar sensor when the vehicle is in motion and / or (ii) classify the received radar data. Generally, the classified received data will be used for subsequent correction of the radar beam tilt, but the classified data may also be used for other purposes, such as post-software classification of the radar data.

[0049] In an example of the present invention, the acceleration sensor 200 will measure the vertical movement of the radar sensor 300 when the vehicle chassis moves, for example, due to the vehicle traveling on a bumpy road, the vehicle accelerating or braking. The acceleration sensor 200 can be directly connected to the radar sensor 300, or alternatively mounted at a certain position on the vehicle chassis to measure the acceleration of the chassis. The measured vertical acceleration can be used to correct the tilt of the automotive radar beam in elevation due to the movement of the vehicle chassis (e.g., bumpy roads, acceleration, braking), or to classify the data received during the movement of the chassis. All measured data will be stored in the memory 330, and the processor 320 will analyze the measured data and perform beam correction and / or data evaluation.

[0050] The memory 330 of the automotive radar microcontroller 350 will have details of the vertical tilt threshold used to determine whether the beam angle of the radar needs correction. The threshold can be calculated based on various parameters of the vehicle (including vehicle acceleration), and in some examples of the present invention, the threshold can be dynamically adjusted according to the specific driving conditions at the time. Typically, the threshold is pre-calculated and stored in the microcontroller 350. In operation of the radar sensor, the threshold is compared with the measured tilt angle as described above.

[0051] In an example of the present invention, tilt correction may be performed as part of a calibration correction. In one example, each vehicle's radar sensor will be calibrated to a set standard at the production factory. The calibration may be for vehicle software, in which case all vehicles in a particular production run will have the same calibration standard. In an example of the present invention, the calibration process may calibrate a correction factor for the measured acceleration values ​​of the sensor. This can be done by measuring the beam tilt of the radar sensor relative to the measured acceleration. These measurements can then be used to correct the tilt back to the expected calibration measurements.

[0052] Figure 54 is a flow chart 400 showing steps in an example of the method of the present invention. At 402, the vertical acceleration of a radar sensor on the vehicle is measured by an acceleration sensor, this output is passed to 404, and the tilt of the radar beam extending from the vehicle due to the change in vehicle motion is calculated, at 406, the radar beam tilt is corrected back to a standard value (by comparing the tilt to a vertical threshold limit stored in the microcontroller 350), or the tilt information is used to evaluate the radar data, and no radar beam adjustment occurs. This correction can be performed using a beam corrector or software control as discussed above. In an example of the present invention, the tilt correction angle corr(t) is equal to the measured vertical acceleration a(t)' multiplied by the correction factor m plus the delay function f(t), as shown in Equation 1 below:

[0053] corr(t)=a(t)*m+f(t); Equation 1

[0054] For example, if 406 results in correction of radar beam tilt via beam steering techniques, this correction may occur on the transmitter or receiver side of sensor 300. In the example of the present invention, for correction on the transmit side, this would be done using e.g. Figure 3 The phase rotator 360 shown physically corrects the beam, while the correction or adjustment of the radar beam at the receiver side will be performed via software control within the automotive radar microcontroller 350, such as Figure 4 shown.

[0055] If the measured radar acceleration is evaluated using 406 instead of correcting for tilt, the data can be used for software processing to evaluate / classify / weight the sensor data. This can be used to improve the reliability of autonomous vehicles, as the evaluated data can be fed back into the development of autonomous vehicles.

[0056] Although examples of the present invention are described with reference to a radar unit suitable for automotive applications, it is contemplated that the concepts described herein may be applicable to other applications, for example: MR3003 radar transceiver, TEF810X radar transceiver; microcontroller: S32R27: S32R radar microcontroller; MMA69XX automotive accelerometer.

[0057] In the foregoing description, the present invention has been described with reference to the specific examples of the embodiments of the present invention. However, it will be apparent that various modifications and changes may be made to the specific examples without departing from the scope of the present invention as set forth in the appended claims, and the claims are not limited to the specific examples described above. The connection as discussed herein may be any type of connection suitable for transmitting a signal from a corresponding node, unit or integrated circuit device or transmitting a signal to the corresponding node, unit or integrated circuit device. Therefore, unless otherwise implied or stated, the connection may be, for example, a direct connection or an indirect connection. In addition, multiple connections may be replaced by a single connection that transmits multiple signals in a serial or time-division multiplexed manner. Similarly, a single single connection carrying multiple signals may be divided into various different connections that carry a subset of these signals. Therefore, there are many options for transmitting signals.

[0058] Those skilled in the art will recognize that the architectures depicted herein are merely exemplary, and that, in fact, many other architectures that achieve the same functionality may be implemented. Thus, any two components combined herein to achieve a particular functionality may be considered to be 'associated' with each other such that the desired functionality is achieved, regardless of the architecture or intermediate components. Thus, any two components combined herein to achieve a particular functionality may be considered to be 'associated' so as to achieve the desired functionality, regardless of the architecture or intermediate components. Likewise, any two components so associated may also be considered to be "operably connected" or "operably coupled" to each other to achieve the desired functionality.

[0059] In addition, those skilled in the art will recognize that the boundaries between the above operations are merely illustrative. Multiple operations may be combined into a single operation, a single operation may be dispersed in additional operations, and the execution of operations may overlap at least partially in time. In addition, alternative embodiments may include multiple examples of specific operations, and the order of operations may be changed in different other embodiments.

[0060] In the claims, any reference numerals placed between parentheses should not be interpreted as limiting the claim. The word 'comprising' does not exclude the existence of other elements or steps other than those listed in the claim. In addition, as used herein, the term "a or an" is defined as one or more than one. Moreover, the use of introductory phrases such as 'at least one' and 'one or more' in the claims should not be interpreted as implying that any particular claim including such introduced claim elements introduced by the indefinite article 'one' will be limited to an invention including only one such element, even when the same claim includes the introductory phrases 'one or more' or 'at least one' and the indefinite article such as 'one'. The use of definite articles is also the same. Unless otherwise stated, terms such as 'first' and 'second' are used to arbitrarily distinguish the elements described by such terms. Therefore, these terms are not necessarily intended to indicate the temporal priority or other priority of these elements. The mere fact that certain measures are described in different claims does not indicate that the combination of these measures cannot be used to obtain advantages.

Claims

1. A radar sensor (300) for a vehicle, characterized in that: include: at least one transmitter (308) and at least one receiver (302) for transmitting and receiving radar signals of the radar sensor (300); An acceleration sensor (200) is used to measure the acceleration of the radar sensor (300) or the vehicle, wherein the acceleration sensor (200) measures the acceleration of the radar sensor (300) at an angle of 30° to the direction of travel of the vehicle. o With 150 o The acceleration in the direction of the angle between a processor (320) coupled to the acceleration sensor (200) to calculate a tilt of a radar signal projected from the vehicle using the measured acceleration; A memory (330) for storing the calculated radar tilt; wherein the sensor (300) is capable of processing the measured acceleration and adjusting the tilt of the radar signal or classifying the measured data in response to the measured acceleration; A beam corrector (360), wherein the beam corrector (360) corrects the tilt back to a standard value, and the tilt correction angle is equal to the vertical acceleration multiplied by a correction factor plus a delay function.

2. The radar sensor (300) according to claim 1, characterized in that The acceleration sensor (200) is coupled to the transmitter (308) of the radar sensor (300).

3. The radar sensor according to claim 1, characterized in that: The direction of the acceleration sensor is 75 degrees to the traveling direction. o With 105 o The angle between.

4. The radar sensor according to claim 1 or claim 2, characterized in that: The beam corrector (360) is a beam steering device or a phase rotator.

5. The radar sensor according to claim 1 or claim 2, characterized in that: The tilt of the radar signal is adjusted in the receiver via software control.

6. The radar sensor according to claim 1 or claim 2, characterized in that: The processor can process the classified data from the radar signal in conjunction with the calculated radar tilt.

7. A method for adjusting a radar signal emitted from a vehicle, characterized in that include: transmitting a radar signal from the vehicle; Measure the acceleration of the vehicle, wherein the acceleration is the acceleration of a radar sensor in the vehicle at an angle of 30° to the direction of travel of the vehicle. o With 150 o The acceleration in the direction of the angle between calculating a tilt of the radar signal using the measured acceleration; The tilt is corrected back to a standard value using a beam corrector, with the tilt correction angle being equal to the vertical acceleration times the correction factor plus a delay function.

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