Estimation device

Abstract

An estimation device (4) mounted on a mobile body includes an acquisition unit (S10), an extraction unit (S20), and an estimation unit (S30, S35, S39). The acquisition unit acquires reflection point information for each of a plurality of reflection points detected by a radar device mounted on the mobile body. The extraction unit extracts at least one road surface reflection point detected by reflection on a road surface from the plurality of reflection points based on the reflection point information. The estimation unit estimates the height of the radar device mounted on the mobile body, i.e., the device height, based on at least the road surface reflection point distance, i.e., the distance from the radar device to the road surface reflection point.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This international application claims the benefit of priority from Japanese Patent Application No. 2019-186316 filed with the Japan Patent Office on October 9, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to an estimation device. Background Art

[0004] Technologies for estimating the offset in the height direction of a radar device are known. For example, Patent Document 1 below discloses a technology in which oncoming vehicles both have radar devices and estimate the offset in the height direction based on the difference between the height of the vehicle's radar device detected by the oncoming vehicle and the height of the radar device stored in advance by the vehicle.

[0005] Patent Document 1: Japanese Patent No. 6386412

[0006] However, as a result of detailed research by the inventors, they discovered that the technique described in Patent Document 1 has a problem in that the displacement in the height direction cannot be estimated using only the vehicle itself. Summary of the Invention

[0007] One aspect of the present disclosure provides a technology capable of estimating the offset in the height direction of a radar device using only a vehicle.

[0008] One embodiment of the present disclosure is an estimation device mounted on a mobile body, comprising an acquisition unit, an extraction unit, and an estimation unit. The acquisition unit is configured to acquire reflection point information for each of a plurality of reflection points detected by a radar device mounted on the mobile body. The reflection point information includes at least a horizontal angle, a vertical angle, and a distance from the radar device to the reflection point. The horizontal angle and the vertical angle are azimuth angles with respect to the reflection point and are calculated based on the direction along the central axis of the radar beam, i.e., the beam direction. The extraction unit is configured to extract at least one road surface reflection point detected by reflection on the road surface from the plurality of reflection points based at least on the reflection point information. The estimation unit estimates the height of the radar device mounted on the mobile body, i.e., the device height, based at least on the road surface reflection point distance, i.e., the distance from the radar device to the road surface reflection point.

[0009] According to this configuration, the height of the device can be estimated using only the vehicle itself, without using the detection results of other vehicles. As a result, the deviation of the radar device in the height direction can be estimated using only the vehicle itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a block diagram showing the configuration of a vehicle control system.

[0011] Figure 2 This is an explanatory diagram for explaining the horizontal irradiation range of radar waves.

[0012] Figure 3 This is an explanatory diagram for explaining the vertical irradiation range of radar waves.

[0013] Figure 4 This is a block diagram illustrating the functions of the signal processing unit.

[0014] Figure 5 This is an explanatory diagram for explaining the positional deviation of the radar device in the height direction.

[0015] Figure 6 This is a flowchart of the adjustment process according to the first embodiment.

[0016] Figure 7 This is a flowchart of the road surface reflection extraction process.

[0017] Figure 8 This is a flowchart of the calculation process of the first embodiment.

[0018] Figure 9 It is an explanatory diagram for explaining estimation of the height deviation amount in the first embodiment.

[0019] Figure 10 This is a flowchart of the adjustment process according to the second embodiment.

[0020] Figure 11 This is a flowchart of the frequency extraction process according to the second embodiment.

[0021] Figure 12 This is an explanatory diagram for explaining how the extraction frequency is stored.

[0022] Figure 13 It is an explanatory diagram for explaining an example of corresponding information.

[0023] Figure 14 It is an explanatory diagram for explaining an example of estimating the height of the device according to the second embodiment.

[0024] Figure 15 It is an explanatory diagram for explaining an example of estimating the height of the device according to a modification of the second embodiment.

[0025] Figure 16 This is a flowchart of the adjustment process according to the third embodiment. DETAILED DESCRIPTION

[0026] The following describes exemplary embodiments of the present disclosure with reference to the accompanying drawings. Furthermore, the term "vertical" is not limited to a strict "vertical" meaning and may be anything other than strictly "vertical" as long as the same effect is achieved. The same also applies to "horizontal" and "aligned."

[0027] [1. First embodiment]

[0028] [1-1. Composition]

[0029] Figure 1 The illustrated vehicle control system 1 is a system installed in a vehicle VH, which is a mobile object. The vehicle control system 1 includes a radar device 2, an onboard sensor group 3, a signal processing unit 4, and an assist actuator 5. Furthermore, the vehicle control system 1 may include a notification device 51 and an onboard height adjustment device 52. Hereinafter, the vehicle VH on which the vehicle control system 1 is installed will also be referred to as the host vehicle VH. The vehicle width direction of the host vehicle VH will also be referred to as the horizontal direction, and the vehicle height direction will also be referred to as the vertical direction.

[0030] like Figure 2 as well as Figure 3 As shown, radar device 2 is mounted in front of the vehicle VH. Radar device 2 radiates radar waves within a predetermined horizontal angular range Ra and a predetermined vertical angular range Rb in front of the vehicle VH. Radar device 2 receives reflected waves from the radiated radar waves and generates reflection point information related to the reflection point where the radar waves were reflected.

[0031] Furthermore, radar device 2 may be a so-called millimeter-wave radar that uses electromagnetic waves in the millimeter-wave band as radar waves, a lidar that uses lasers as radar waves, or a sonar that uses sound waves as radar waves. In short, the antenna unit that transmits and receives radar waves is configured to detect the direction of arrival of reflected waves in both the horizontal and vertical directions. The antenna unit may also include an array antenna arranged in the horizontal and vertical directions.

[0032] In this embodiment, radar device 2 is installed so that its beam direction aligns with the front-to-back direction of the vehicle VH, i.e., its travel direction, and is used to detect various target objects in front of the vehicle VH. The beam direction refers to the direction along the central axis CA of the emitted radar beam. Radar device 2 generates reflection point information.

[0033] Reflection point information refers to information related to the reflection point. This information includes at least the azimuth and distance of the reflection point. The distance of the reflection point refers to the distance between the radar device 2 and the reflection point. Furthermore, the radar device 2 may be configured to detect the relative speed of the reflection point relative to the vehicle VH and the reception intensity of the radar beam reflected by the reflection point. The reflection point information may also include the relative speed and reception intensity of the reflection point.

[0034] like Figure 2 、 3 As shown, the azimuth of the reflection point refers to at least one of the horizontal angle (hereinafter referred to as the horizontal angle) Hor and the vertical angle (hereinafter referred to as the vertical angle) Ver at the reflection point, calculated with reference to the direction along the central axis CA of the radar beam, i.e., the beam direction. In this embodiment, the reflection point information includes both the vertical angle Ver and the horizontal angle Hor as information indicating the azimuth of the reflection point.

[0035] In this embodiment, radar device 2 uses the FMCW method, alternating between transmitting radar waves in uplink and downlink modulation intervals according to a pre-set modulation cycle and receiving reflected radar waves. FMCW is an abbreviation for Frequency Modulated Continuous Wave (FMCW). In this embodiment, radar device 2 detects the azimuth angle (hor) and vertical angle (ver) of the reflection point, the distance to the reflection point, the relative velocity to the reflection point, and the received power of the received radar wave as reflection point information, as described above, for each modulation cycle. Hereinafter, the received power of the received radar wave is referred to as the reflected power.

[0036] The onboard sensor group 3 is at least one sensor mounted on the vehicle VH to detect the status of the vehicle VH, etc. The onboard sensor group 3 may also include a vehicle speed sensor. The vehicle speed sensor detects vehicle speed based on wheel rotation. Furthermore, the onboard sensor group 3 may also include a camera. This camera captures the same range as the radar wave irradiation range of the radar device 2. Furthermore, the onboard sensor group 3 may also include an acceleration sensor. The acceleration sensor detects the acceleration of the vehicle VH. Furthermore, the onboard sensor group 3 may also include a yaw rate sensor. The yaw rate sensor detects the rate of change in the yaw angle, which indicates the tilt of the vehicle VH's traveling direction relative to the front of the vehicle VH.

[0037] The signal processing unit 4 includes a microcomputer 40. The microcomputer 40 includes a CPU 41, a ROM 43, a RAM 44, and a semiconductor memory such as a flash memory (hereinafter referred to as the memory 42). The CPU 41 executes programs. The ROM 43 stores the programs executed by the CPU 41 and data referenced during the execution of the programs. The RAM 44 temporarily stores data.

[0038] like Figure 4 As shown, the signal processing unit 4 includes at least a recognition unit 45 and an estimation unit 46 as functional components realized by the CPU 41 executing a program.

[0039] The assistance execution unit 5 controls various in-vehicle devices based on the processing results of the recognition unit 45 included in the signal processing unit 4 to perform predetermined driving assistance. The various in-vehicle devices that are controlled may include monitors that display images and acoustic devices that output warning sounds or guidance sounds. Furthermore, control devices that control the internal combustion engine, power transmission mechanism, brake mechanism, and the like of the vehicle VH may also be included.

[0040] The notification device 51 is a sound output device installed in the vehicle cabin, and outputs a warning sound to the passengers of the host vehicle VH. Alternatively, an acoustic device or the like included in the assist execution unit 5 may be used as the notification device 51.

[0041] The mounting height adjustment device 52 includes a motor and a gear mounted on the radar device 2. The mounting height adjustment device 52 rotates the motor based on a drive signal output from the signal processing unit 4. As a result, the rotational force of the motor is transmitted to the gear, enabling the radar device 2 to be moved vertically up and down.

[0042] [1-2. Processing]

[0043] [Identification Department]

[0044] The recognition unit 45 performs the object recognition function. This object recognition function detects the lane in which the host vehicle VH is traveling, preceding vehicles traveling in the same lane as the host vehicle VH, and other obstacles based on the reflection point information obtained from the radar device 2 and various information obtained from the on-board sensor group 3. The results of the object recognition are output to the assistance execution unit 5 and other units.

[0045] [Estimation Department]

[0046] The radar device 2 is accurately installed at a predetermined position on the vehicle VH in its initial state, such as when shipped from the factory. The initial height referred to below refers to the height of the radar device 2 from the road surface at that time. For example, the initial height is pre-stored in a memory 42 such as a ROM 43. Based on the detection results of the radar device 2 installed at the initial height, the recognition unit 45 can accurately perform the object recognition function.

[0047] However, in the vehicle VH, the radar device 2 may have a height deviation. Examples of height deviation are Figure 5 The radar device 200 shown by the dotted line represents the radar device installed at the initial height F. For example, if the user replaces the tires of the host vehicle VH with tires having a different radius than when the initial height was stored, or if the user replaces the suspension of the host vehicle VH with a different suspension than when the initial height was stored, a height deviation may occur.

[0048] Therefore, the estimation unit 46 estimates the height and height offset of the radar device 2 based on the adjustment process described below. The estimation unit 46 implements these functions through the adjustment process. The height refers to the height of the radar device 2 mounted on the vehicle VH, measured from the road surface. Height offset refers to a vertical deviation of the radar device 2 from its initial, predetermined height. The height offset represents the magnitude of this height offset as a distance.

[0049] Here, the coordinate axes of the vehicle VH and the radar device 2 are described. Figure 2 as well as Figure 3 As shown, the coordinate axes of the host vehicle VH are the vertical axis Zc extending in the plumb direction, the horizontal axis Yc extending in the horizontal direction, and the travel axis Xc extending in the direction of travel of the host vehicle VH. The vertical axis Zc, the horizontal axis Yc, and the travel axis Xc are orthogonal to each other.

[0050] On the other hand, Figure 5 As shown, the coordinate axes of the radar device 2 are the vertical axis Zs extending vertically along the radar device 2, the horizontal axis Ys extending horizontally along the radar device 2, and the front-rear axis Xs extending front-to-rear along the radar device 2 when the radar device 2 is mounted on the vehicle VH. The vertical axis Zs, the horizontal axis Ys, and the front-rear axis Xs are orthogonal to each other. The device coordinates are coordinates expressed based on the coordinate axes of the radar device 2.

[0051] In this embodiment, in which the radar device 2 is installed in front of the vehicle VH, the longitudinal axis Xs is equal to the central axis CA. In other words, the height offset corresponds to the vertical distance between the travel direction axis Xc and the longitudinal axis Xs of the radar device 2 .

[0052] [1-2-1. Adjustment process]

[0053] use Figure 6 The flowchart of FIG. 4 illustrates the adjustment process executed by the estimation unit 46. This process is started when the ignition switch is turned on.

[0054] Once this process is initiated, the estimation unit 46 acquires the aforementioned reflection point information from the radar device 2 in S10. As described above, the reflection point information is information about each of the multiple reflection points detected by the radar device 2 mounted on the vehicle VH, and includes at least the horizontal and vertical angles representing the azimuth angles, and the distance from the radar device 2 to the reflection point. Hereinafter, the reflection point identified based on the reflection point information is referred to as the acquired reflection point. Furthermore, the estimation unit 46 acquires various detection results, including the vehicle speed Cm, from the onboard sensor group 3.

[0055] In S20 , the estimation unit 46 performs road surface reflection extraction processing. Road surface reflection extraction processing is used to extract reflection points on the road surface, or road surface reflection points, from the acquired reflection points. A road surface reflection point is at least one reflection point detected by reflection from the road surface. Details of the road surface reflection extraction processing will be described later.

[0056] In S30, the estimation unit 46 performs a calculation process. The calculation process is a process of arithmetically estimating the height of the device based on at least the road surface reflection point distance. The road surface reflection point distance is the distance from the radar device 2 to the road surface reflection point.

[0057] In S40 , the estimation unit 46 determines the height offset. In this embodiment, the height offset refers to the difference between the device height estimated in S30 and the initial height. The estimation unit 46 stores the determined height offset in the memory 42 .

[0058] In S50, the estimation unit 46 determines whether adjustment by the mounted height adjustment device 52 is necessary based on the altitude offset estimated in S40. Specifically, the estimation unit 46 determines that adjustment is necessary if the altitude offset is greater than a predetermined threshold distance. In other words, the threshold distance indicates the vertical offset of the radar device 2 that requires adjustment by the mounted height adjustment device 52. The threshold distance may also be pre-stored in the memory 42.

[0059] The estimation unit 46 shifts the process to S90 when the height deviation amount is less than the threshold distance and adjustment is not required, and shifts the process to S60 when the height deviation amount is greater than the threshold distance and adjustment is required.

[0060] In S60, the estimation unit 46 determines whether the height offset estimated in S40 is within the adjustable range of the mounted height adjustment device 52. If the height offset estimated in S40 is within the adjustable range, the estimation unit 46 proceeds to S70; if not, the estimation unit 46 proceeds to S80. The adjustable range may also be pre-stored in the memory 42.

[0061] In S70, the estimation unit 46 uses the height adjustment device 52 to adjust the height of the radar device 2 by the height offset estimated in S40. In other words, the estimation unit 46 adjusts the height of the radar device 2 by moving it vertically in the vehicle height direction about the front-rear axis Xs of the radar device 2 by the height offset amount. The estimation unit 46 then terminates the adjustment process.

[0062] Alternatively, the estimation unit 46 may calculate the position coordinates of the reflection point acquired in S10 in a process separate from the present adjustment process, and adjust the position coordinates by increasing or decreasing the height of the calculated position coordinates by the height offset estimated in S40. The recognition unit 45 may then perform the aforementioned object recognition based on the adjusted position coordinates of the reflection point.

[0063] In S80, the estimation unit 46 outputs diagnostic information indicating that an altitude offset has occurred in the radar device 2 to an external device of the estimation unit 46. Hereinafter, diagnostic information indicating that an altitude offset has occurred in the radar device 2 is referred to as an altitude offset diagnosis. The external device may also be the notification device 51. For example, the estimation unit 46 may output the altitude offset diagnosis to the notification device 51. The notification device 51 may also output a warning sound based on the altitude offset diagnosis.

[0064] In S90, the estimation unit 46 determines whether the ignition switch is off. If the ignition switch is not off, the estimation unit 46 proceeds to S10. On the other hand, if the ignition switch is off, the estimation unit 46 ends the adjustment process.

[0065] [1-2-2. Road surface reflection extraction processing]

[0066] Next, use Figure 7 The flowchart of FIG. 1 illustrates the road surface reflection extraction process executed by the estimation unit 46 in S20 of the adjustment process.

[0067] In S100, the estimation unit 46 acquires detection results of the state of the host vehicle VH and the like by various sensors from the vehicle-mounted sensor group 3. The detection results mentioned here may include the vehicle speed, acceleration, yaw angle, and the like of the host vehicle VH.

[0068] In S110 , the estimation unit 46 determines whether to extract a road surface reflection point based on the detection results of the state of the host vehicle VH and the like acquired from the vehicle-mounted sensor group 3 .

[0069] Specifically, the estimation unit 46 determines whether the body of the host vehicle VH is stable relative to the road surface based on the detection results of the state of the host vehicle VH, and determines to extract the road surface reflection point if the body of the host vehicle VH is stable relative to the road surface.

[0070] The body of the host vehicle VH is stable relative to the road surface when the vehicle VH is not tilting or moving up and down relative to the road surface. In other words, the body of the host vehicle VH is stable relative to the road surface when the vehicle VH is not traveling on a curve with a large curvature or when the vehicle VH is not traveling on a road with a large uneven surface.

[0071] Here, when the vehicle is not traveling on a road with significant unevenness, it can be considered to be traveling on a flat road. In this case, the speed and acceleration are considered to be higher than when traveling on a road with significant unevenness. On the other hand, when the vehicle is not traveling on a curve with significant curvature, it can be considered to be traveling on a road close to a straight road. In this case, the speed and acceleration are higher than when traveling on a curve with significant curvature, and the rate of change of the yaw angle is often lower than when traveling on a curve with significant curvature.

[0072] Therefore, the estimation unit 46 may determine that the body of the host vehicle VH is stable relative to the road surface and extract road surface reflection points when the vehicle speed of the host vehicle VH is greater than a predetermined speed threshold, and may determine that the body of the host vehicle VH is stable relative to the road surface and extract road surface reflection points. Alternatively, the estimation unit 46 may determine that the body of the host vehicle VH is unstable relative to the road surface and not extract road surface reflection points when the vehicle speed of the host vehicle VH is less than the speed threshold.

[0073] Similarly, the estimation unit 46 may determine that the body of the host vehicle VH is stable relative to the road surface and determine to extract a road surface reflection point when the acceleration of the host vehicle VH is greater than a predetermined acceleration threshold. Similarly, the estimation unit 46 may determine that the body of the host vehicle VH is stable relative to the road surface and determine to extract a road surface reflection point when the rate of change of the yaw angle of the host vehicle VH is less than a predetermined threshold.

[0074] The estimation unit 46 moves the process to S120 when determining that the road surface reflection point is to be extracted, and moves the process to S180 when determining that the road surface reflection point is not to be extracted.

[0075] In S120, the estimation unit 46 selects one acquired reflection point from all acquired reflection points. The estimation unit 46 executes the processes of S130 to S195 on the selected acquired reflection point (hereinafter simply referred to as an acquired reflection point).

[0076] In S130, the estimation unit 46 determines whether the acquired reflection point is within a predetermined azimuth range, i.e., an extraction range, that includes the central axis CA in the horizontal direction. If the acquired reflection point is within the azimuth range, the estimation unit 46 proceeds to S140. If the selected acquired reflection point is not within the azimuth range, the estimation unit 46 proceeds to S190.

[0077] In other words, the estimation unit 46 extracts the acquired reflection points from the plurality of acquired reflection points that are within the extraction range. The extraction range can be defined, for example, as a range of ± several to several tens of degrees horizontally encompassing the central axis CA. In other words, in this embodiment, where the radar device 2 is installed in front of the vehicle VH, the extraction range is defined as a predetermined range near the direction of travel of the vehicle VH. Alternatively, the extraction range can be predetermined through experiments or the like. The extraction range is pre-stored in the memory 42.

[0078] In S140, the estimation unit 46 determines whether the distance between the selected reflection acquisition point and the radar device 2 is less than a predetermined distance threshold. If the distance between the selected reflection acquisition point and the radar device 2 is less than the distance threshold, the estimation unit 46 proceeds to S150. If the distance between the selected reflection acquisition point and the radar device 2 is greater than the distance threshold, the estimation unit 46 proceeds to S190.

[0079] In other words, the estimation unit 46 extracts the acquired reflection points whose distance from the radar device 2 is less than a distance threshold. The distance threshold is stored in the memory 42 in advance.

[0080] In S150, the estimation unit 46 determines whether the acquired reflection point is a stationary reflection point. If the acquired reflection point is a stationary reflection point, the estimation unit 46 proceeds to S160; if not, the estimation unit proceeds to S190. A stationary reflection point is a reflection point where radar waves are reflected by a stationary object.

[0081] In other words, the estimation unit 46 extracts stationary reflection points from the acquired reflection points. Specifically, the estimation unit 46 uses the vehicle speed Cm acquired in S10, sets the relative speed included in the reflection point information to q, sets a predetermined lower speed threshold to ε1, and sets an upper speed threshold to ε2, and extracts, as stationary reflection points, those acquired reflection points that satisfy ε1 ≤ q / Cm < ε2. In other words, the estimation unit 46 extracts, as stationary reflection points, those acquired reflection points where the ratio of the vehicle speed Cm to the relative speed q is within the predetermined speed threshold range of greater than ε1 and less than ε2.

[0082] If the direction from the stationary reflection point toward the radar device 2 coincides with the beam direction, the vehicle's speed Cm and the relative speed q at the reflection point are equal, and the direction of the relative speed q is opposite to the vehicle's speed Cm, resulting in q / Cm = -1. Thus, the reflection point with q / Cm = -1 is considered a stationary reflection point.

[0083] However, the vehicle speed Cm obtained from the onboard sensor group 3 may not necessarily match the actual vehicle speed due to factors such as wheel slip. Furthermore, the relative speed q detected by the radar device 2 also contains errors. Therefore, even at a stationary reflection point, q / Cm may not necessarily equal -1. The lower speed threshold ε1 and the upper speed threshold ε2 can be appropriately set to take these factors into account.

[0084] In S160, the estimation unit 46 determines whether the reflected power at the acquired reflection point is less than a predetermined power threshold. If the reflected power at the acquired reflection point is less than the power threshold, the estimation unit 46 proceeds to S170. If the reflected power at the acquired reflection point is greater than the power threshold, the estimation unit 46 proceeds to S190.

[0085] In other words, the estimation unit 46 extracts the reflection points where the reflected power is less than the power threshold. Considering that the reflected power from the road surface is, for example, less than the reflected power from other vehicles, the power threshold can be appropriately determined based on the reflected power from the road surface. For example, the power threshold can be predetermined through experiments. The power threshold is pre-stored in the memory 42.

[0086] In S170, the estimation unit 46 determines whether the acquired reflection point is recognized as a road surface in the captured image by the camera. If the acquired reflection point is estimated as a road surface in the captured image, the estimation unit 46 proceeds to S180; if the acquired reflection point is not estimated as a road surface in the captured image, the estimation unit 46 proceeds to S190.

[0087] In other words, the estimation unit 46 extracts the acquired reflection points recognized as the road surface in the captured image. In addition, the estimation unit 46 can also be configured to acquire the camera captured image in a process different from the present adjustment process and estimate the azimuth range recognized as the road surface in the captured image.

[0088] In S180 , the estimation unit 46 determines that the acquired reflection point is a road surface reflection point, stores the three-dimensional coordinates of the acquired reflection point as a road surface reflection point in the memory 42 , and moves the process to S195 .

[0089] In S190 , the estimation unit 46 determines that the acquired reflection point is not a road surface reflection point, does not store the acquired reflection point in the memory 42 , and moves the process to S195 .

[0090] In S195, the estimation unit 46 determines whether all acquired reflection points have been verified as road surface reflection points. If verification has not been completed, the estimation unit 46 proceeds to S110 and repeats the processes S110-S195. If verification has been completed, the estimation unit 46 terminates the road surface reflection extraction process.

[0091] In other words, in the road surface reflection extraction process of the present embodiment, among the acquired reflection points, those that satisfy all of the following (a) to (d) are extracted as road surface reflection points.

[0092] (a) It is located within the extraction range including the central axis CA in the horizontal direction.

[0093] (b) The distance to the radar device 2 is smaller than the distance threshold.

[0094] (c) is the stationary reflection point.

[0095] (d) The reflected power is less than the power threshold.

[0096] (e) Recognized as a road surface in the image captured by the camera.

[0097] Furthermore, the road surface reflection extraction process may be configured to satisfy at least (a) of the above (a)-(e). In other words, the road surface reflection extraction process may be configured to satisfy (a) and further satisfy at least one of (b)-(e). Alternatively, the road surface reflection extraction process may be configured to satisfy at least (a) and (b). In other words, the road surface reflection extraction process may be configured to satisfy (a) and (b) and further satisfy at least one of (c)-(e).

[0098] [1-2-3. Calculation Processing]

[0099] Next, use Figure 8 The flowchart of FIG. 1 illustrates the calculation process executed by the estimation unit 46 in S30 of the adjustment process.

[0100] In S210, the estimation unit 46 obtains the distance to the road surface reflection point and the vertical angle θ as the azimuth angle of the road surface reflection point based on the reflection point information for at least one road surface reflection point identified in S20. Ver .

[0101] In S220, the estimation unit 46 takes the height of the radar device 2 to be estimated (ie, the device height) as the unknown parameter H and calculates the unknown parameter H. Figure 9 As shown, based on the road surface reflection distance R and the vertical angle θ, the unknown parameter H is expressed by the following equation (1).

[0102] [Mathematical formula 1]

[0103] H=R×sinθver…(1)

[0104] In S230, the estimating unit 46 estimates the unknown parameter H calculated in S220 as the device height. Alternatively, if there are multiple road surface reflection points, the estimating unit 46 may calculate the unknown parameter H for each road surface reflection point and estimate the device height as the average of these values. The estimating unit 46 stores the estimated device height in the memory 42, thus concluding the calculation process.

[0105] [1-3. Effect]

[0106] (1a) In S30, the signal processing unit 4 estimates the height of the radar device 2 mounted on the host vehicle VH, i.e., the device height, based at least on the road surface reflection point distance. As a result, the device height can be estimated solely using the host vehicle VH without communicating with other vehicles. Furthermore, the height offset can be estimated solely using the host vehicle VH.

[0107] (1b) In S30, the signal processing unit 4 may use the device height as the unknown parameter H and calculate the value of the unknown parameter H based on the unknown parameter H, the distance R from the road surface reflection point, and the vertical angle θ. Ver The relational expression that holds between them is equation (1), and the unknown parameter H, that is, the height of the device, is calculated. As a result, the height of the device can be calculated with good accuracy based on the relational expression.

[0108] (1c) The signal processing unit 4 may estimate the difference between the device height estimated in S30 and the initial height as the height offset in S40. As a result, the height offset can be estimated using only the vehicle VH.

[0109] [2. Second embodiment]

[0110] [2-1. Structure]

[0111] The basic structure of the second embodiment is the same as that of the first embodiment, so the following description will focus on the differences.

[0112] In the first embodiment described above, the signal processing unit 4 estimates the device height arithmetically based on equation (1). In contrast, in the second embodiment, the signal processing unit 4 estimates the device height statistically based on correspondence information described later.

[0113] [2-2. Processing]

[0114] [2-2-1. Adjustment Process]

[0115] Next, use Figure 10 The flowchart of FIG. 4 is a flowchart of FIG. 5 , which is a flowchart of FIG. 6 , which is a flowchart of FIG. 7 , and which is a flowchart of FIG. 8 , which is a flowchart of FIG. 9 , which is a flowchart of FIG. 1 ... Figure 6) and the adjustment process of the second embodiment is described. Along with the above differences, in the height offset estimation process performed by the signal processing unit 4 of the second embodiment, Figure 6 The S30 and S40 shown are replaced by Figure 10 S35, S42 shown, and in Figure 10 S37 has been added. In addition, Figure 10 The processing of S10-S20, S50-S90 and Figure 6 The processing of S10-S20 and S50-S90 is the same, so some descriptions are simplified.

[0116] The estimation unit 46 performs S10-S20 and Figure 6 The same processing is performed in S10-S20.

[0117] Following S20, the estimation unit 46 executes frequency extraction processing in S35. The frequency extraction processing generates an extraction frequency (described later) for each road surface reflection point and estimates the device height using the extracted frequency. The estimated device height is stored in the memory 42. Furthermore, during the frequency extraction processing, the number of times the frequency extraction processing is executed (hereinafter referred to as the extraction count) K is counted and stored in the memory 42.

[0118] In the next step S37, the estimation unit 46 determines whether the number of extractions K is greater than a predetermined extraction threshold. If the estimation unit 46 determines that the number of extractions K is greater than the extraction threshold, the process proceeds to S42. On the other hand, if the estimation unit 46 determines that the number of extractions K is less than the extraction threshold, the process proceeds to S10 and the processes S10-S37 are repeated.

[0119] In S42 , the estimation unit 46 determines the height offset. In the second embodiment, the height offset refers to the difference between the device height estimated in S35 and the initial height. The estimation unit 46 stores the determined height offset in the memory 42 .

[0120] The estimation unit 46 performs the following steps S50 to S90. Figure 6 The same processing is performed in S50 to S90 shown.

[0121] [2-2-2. Frequency extraction processing]

[0122] Next, use Figure 11 The flowchart of FIG. 1 illustrates the frequency extraction process executed by the estimation unit 46 in S35 of the adjustment process.

[0123] In S310, the estimation unit 46 obtains the device coordinates (x s ,y s , z sThe estimation unit 46 may be configured to calculate the device system coordinates of at least the road surface reflection point based on the reflection point information in a process different from the adjustment process.

[0124] In the next step S320, the estimation unit 46 calculates the extraction frequency and stores the calculated extraction frequency in the memory 42. The extraction frequency represents the value obtained by adding the number of times the road surface reflection point is extracted according to the position of each road surface reflection point. The position of the road surface reflection point mentioned here is determined by the device system coordinate (x s ,y s , z s ) in the two elements (x s ,y s ) represents. In other words, the position of the road surface reflection point here refers to the position on the plane representing the road surface. s ,y s ) represents the position on the plane of the road surface (x s ,y s ) extraction frequency.

[0125] For example, Figure 12 As shown, the frequency P(x s ,y s ) can also be expressed as each position on the plane of the road surface (x s ,y s ) is stored in the memory 42. In this step, the estimation unit 46 extracts the frequency P(x s ,y s ) increases by 1 as the new extraction frequency P(x s ,y s ), covering the extraction frequency P(x s ,y s ) and stored in memory 42.

[0126] The estimation unit 46 then determines in S330 whether the extraction frequency P (x s ,y s The estimation unit 46 does not calculate the extraction frequency P(x) for all the road surface reflection points. s ,y s ) in the case of which the process moves to S310, and the extraction frequency P(x s ,y s ) in the case of which the processing moves to S340.

[0127] The estimation unit 46 determines the extraction frequency P(x s ,y s )The position of the maximum road surface reflection point (xs ,y s ).

[0128] The estimation unit 46 then determines in S350 whether the extraction frequency P(x s ,y s ) is the maximum road surface reflection point is one. The estimation unit 46 extracts the frequency P(x s ,y s ) If there is only one maximum road surface reflection point, the process moves to S360, and the frequency P(x s ,y s ) When there are multiple maximum road surface reflection points, the process moves to S370.

[0129] The estimation unit 46 determines the calculation position in S360 and S370. The calculation position refers to the frequency P(x s ,y s ) The position of the maximum road surface reflection point. The calculated position becomes a different position depending on the device height of the radar device 2. Generally speaking, the lower the device height, the closer the calculated position becomes to the position of the vehicle VH.

[0130] Here, in S360, the estimation unit 46 calculates the extraction frequency P(x s ,y s )The position of the maximum road surface reflection point (x s ,y s ) is stored in memory 42 as the calculated position.

[0131] On the other hand, the estimation unit 46 may also, in S370, convert the plurality of extraction frequencies P(x s ,y s ) is the largest road surface reflection point closest to the front-rear axis Xs as the calculated position and is stored in the memory 42. In other words, the road surface reflection point at the position (xs) representing the road surface reflection point may be stored as the calculated position. s ,y s ) in the element y s The position of the road surface reflection point closest to 0 is determined as the calculation position.

[0132] In addition, the present disclosure is not limited to this. For example, the estimation unit 46 may also calculate the extraction frequency P(x s ,y s ) is the average position of the positions of the multiple road surface reflection points with the largest value, and the average position is determined as the calculated position. Alternatively, the estimation unit 46 may also extract the frequency P(x s ,y s) When there are three or more maximum road surface reflection points, the central position of these multiple road surface reflection points is calculated and the central position is determined as the calculation position.

[0133] In S380, the estimation unit 46 acquires the correspondence information. The correspondence information may be pre-stored in the ROM 43. The correspondence information can be generated in advance based on experiments, simulations, etc.

[0134] Corresponding information refers to information based on experiments, etc., which is information indicating the correspondence between the position of the road surface observed at the maximum frequency by the radar device 2 set at a predetermined measurement height and the measurement height at that time. The measurement height can include multiple heights. In addition, the position of the above-mentioned road surface can be represented by at least the front-to-back distance. The front-to-back distance refers to the distance in the front-to-back direction from the radar device 2. In other words, the front-to-back distance is the distance in the direction along the front-to-back axis Xs. In this embodiment, the position of the above-mentioned road surface is represented by the front-to-back distance. Examples of corresponding information are as follows. Figure 13 shown.

[0135] For example, through experiments, it is possible to observe various road conditions multiple times using a radar device 2 installed at a certain measurement height under the same conditions as when installed at the vehicle VH. Furthermore, it is possible to record the location (i.e., the distance between the front and rear) that is most frequently detected as a road surface and the measured height at that time. By observing at multiple measured heights, corresponding information can be generated.

[0136] In S390, the estimation unit 46 determines the measured height corresponding to the calculated position based on the correspondence information. Specifically, the estimated height corresponding to the calculated position (x s ,y s ) shows the front-back distance, that is, x s The estimating unit 46 then estimates the measured height as the device height. The estimating unit 46 stores the estimated device height in the memory 42.

[0137] In this embodiment, the beam direction is consistent with the direction of the traveling direction axis Xc, and the vertical angle θ can be used to determine the distance R between the road surface reflection point and the vertical angle θ. Ver , based on formula (2), the calculated position (x s ,y s ) shows the front-back distance x s In other words, the frequency extraction process can be said to be based on at least the height of the road surface reflection point from the estimation device.

[0138] [Mathematical formula 2]

[0139] x s =R×cosθver…(2)

[0140] In addition, in this step, the estimation unit 46 increments the number of extractions K by 1, overwrites and stores the number of extractions K in the memory 42 as the new number of extractions K. With this, the estimation unit 46 ends the extraction frequency processing.

[0141] [2-2-3. Action]

[0142] exist Figure 14 An example of the result of the frequency extraction process is shown in FIG. 1 , and the position of each road surface reflection point (x s ,y s ) at the extraction frequency P(x s ,y s ) as an example of a histogram diagram. Figure 14 The example shown in the upper part of is an example in which the calculated position is determined to be Xa[m]. In this case, the estimation unit 46 is based on Figure 13 The corresponding information shown in the figure estimates the device height as Ya[m]. Figure 14 The example shown in the lower part of is an example where the calculated position is determined to be Xb[m] (Xa>Xb). In this case, the estimation unit 46 is based on Figure 13 According to the corresponding information shown, the device height is estimated to be Yb[m] (Ya>Yb).

[0143] [2-3. Effect]

[0144] According to the second embodiment described in detail above, the effect (1a) of the first embodiment described above is achieved, and the following effects are also achieved.

[0145] (2a) In S320, the signal processing unit 4 may generate an extraction frequency representing a value obtained by summing the number of times a road surface reflection point is extracted during a predetermined acquisition period, for each road surface reflection point position. The acquisition period corresponds to a period during which the extraction process is repeated a number of times corresponding to the extraction threshold. In S380, the signal processing unit 4 may also obtain corresponding information from the memory 42. In S390, the signal processing unit 4 may also determine, based on the corresponding information, a measured height corresponding to the position of the road surface reflection point with the highest extraction frequency, i.e., the calculated position, and estimate the measured height as the device height.

[0146] As a result, the signal processing unit 4 can estimate the device height and the height offset with high accuracy in a statistical manner based on the correspondence information.

[0147] (2b) In S35, when the estimation unit 46 has obtained the positions of multiple road surface reflection points with the highest extraction frequency, it may also determine the position of the road surface reflection point closest to the front-rear axis Xs as the calculated position. As a result, the device height can be estimated based on the road surface reflection point that is more accurately identified as the road surface.

[0148] [2-4. Modifications]

[0149] (Variation 2a)

[0150] In S370, the estimation unit 46 may also calculate the extraction frequencies P(x s ,y s ) the maximum road surface reflection point, and uses the central position as the calculation position and determines the device height based on the corresponding information. Alternatively, the estimation unit 46 may also, in S370, calculate the multiple extraction frequencies P(x s ,y s ) the maximum road reflection point, and x s The average value of the calculated position is used to estimate the device height based on the corresponding information. This makes it possible to average the deviations in the positions of the road surface reflection points and estimate the device height with good accuracy.

[0151] (Variant 2b)

[0152] The estimation unit 46 may not calculate the extraction frequency P (x s ,y s ), and calculate the extraction frequency corresponding to the position of the road surface reflection point represented in one dimension.

[0153] In other words, the extracted frequency can also be obtained by adding the number of times the road surface reflection point is extracted according to the position of each road surface reflection point, and the position of the road surface reflection point is obtained by the device system coordinate (x s ,y s , z s ) an element (x s ) represents the position. The position here is represented by the distance along the front-back axis Xs, that is, the front-back distance. s ) to express the position (x s ) is the extraction frequency of the road surface reflection point on .

[0154] Specifically, in this modification, the estimation unit 46 may determine the extraction frequency P(x s )The position of the maximum road surface reflection point (x s ). In addition, when multiple extraction frequencies P(x s ) the maximum road surface reflection point, and then move to S370, the estimating unit 46 may also calculate the positions (x s ) is determined as the calculation position.

[0155] exist Figure 15An example of the result of the frequency extraction process is shown in FIG. 1 , and the position of each road surface reflection point (x s ) at the extraction frequency P(x s ) as an example of a histogram diagram. Figure 15 The example shown in the upper part of is an example in which the calculated position is determined to be Xa[m]. In this case, the estimation unit 46 is based on Figure 13 The corresponding information shown in the figure estimates the device height as Ya[m]. Figure 15 The example shown in the lower part of is an example where the calculated position is determined to be Xb[m] (Xa>Xb). In this case, the estimation unit 46 is based on Figure 13 According to the corresponding information shown, the device height is estimated to be Yb[m] (Ya>Yb).

[0156] [3. Third embodiment]

[0157] [3-1. Structure]

[0158] The basic structure of the third embodiment is the same as that of the first embodiment, so the following description will focus on the differences.

[0159] The third embodiment differs from the first embodiment in that the signal processing unit 4 estimates the device height using equation (1) as in the first embodiment, estimates the device height based on the corresponding information as in the second embodiment, and estimates the final device height based on these estimation results.

[0160] Hereinafter, the device height estimated arithmetically based on equation (1) as in the first embodiment is referred to as the first height. Also, the device height estimated statistically based on the correspondence information as in the second embodiment is referred to as the second height.

[0161] [3-2. Processing]

[0162] Next, use Figure 16 The flowchart of FIG. 4 is a flowchart of FIG. 5 , which is a flowchart of FIG. 6 , which is a flowchart of FIG. 7 ... Figure 6 ) and the adjustment process of the third embodiment is described. Along with the above differences, in the adjustment process performed by the signal processing unit 4 of the third embodiment, Figure 6 The S40 shown is replaced by Figure 16 S44 shown, and in Figure 16 S35, S37, and S39 have been added. In addition, Figure 16 The processing of S10-S30, S50-S90 and Figure 6 The processing of S10-S30 and S50-S90 is the same. Figure 16 The processing of S35 and S37 in Figure 10 The processing of S35 and S37 is the same, so some descriptions are simplified.

[0163] The estimation unit 46 performs S10-S20 and Figure 6 The same processing is performed in S10-S20.

[0164] The estimation unit 46 then performs the following steps in S30: Figure 6 However, in the third embodiment, S30 is repeatedly executed a number of times corresponding to the extraction threshold. Each time S30 is executed, the estimation unit 46 may calculate the average of the first height stored in the memory 42 and the calculated first height in the calculation process S230, and overwrite the average as the new first height in the memory 42.

[0165] In the next S35, the estimation unit 46 performs the Figure 10 The same frequency extraction process as in S35 is performed, and the process proceeds to S37. However, the estimation unit 46 may store the estimated device height as the second height in the memory 42 in S35.

[0166] The estimation unit 46 then performs the following steps in S37: Figure 10 The same treatment as the S37.

[0167] In the next step S39 , the estimation unit 46 calculates the average of the first height estimated in S30 and the second height estimated in S35 , and estimates the average as the final device height. The estimation unit 46 may store the final device height in the memory 42 .

[0168] In the next step S44 , the estimation unit 46 determines the height offset. In the third embodiment, the height offset refers to the difference between the final device height determined in S44 and the initial height. The estimation unit 46 may store the estimated height offset in the memory 42 .

[0169] The estimation unit 46 performs the following steps S50 to S90. Figure 6 The same treatment is applied to the S50-S90.

[0170] [3-3. Effect]

[0171] (3a) In S39, the estimating unit 46 estimates the final device height based on the first device height calculated in S30 and the second device height determined in S35. As a result, since the device height is estimated based on multiple different methods, the accuracy of the estimated device height can be further improved.

[0172] (3b) If the altitude deviation estimated in S44 is greater than the threshold distance and outside the adjustable range, the estimation unit 46 may output the altitude deviation diagnosis described above to the notification device 51 that issues the notification. This allows for appropriate notification based on the device altitude robustly estimated using multiple different methods. In other words, unnecessary notifications that cause inconvenience to passengers can be reduced.

[0173] [3-4. Modifications]

[0174] (Variation 3a)

[0175] For example, the estimation unit 46 may also perform the frequency extraction process in S370 similarly to (Variation 2a) to extract multiple frequencies P(x s ,y s )The maximum road surface reflection point is selected, the central position is used as the calculation position and the device height is estimated based on the corresponding information.

[0176] (Variation 3b)

[0177] For example, the estimation unit 46 may also extract the frequency based on the position (x s The extraction frequency P(x) of the road surface reflection point at s ) and corresponding information to estimate the height of the device.

[0178] (Variation 3c)

[0179] The estimation unit 46 may also report when at least one of the following conditions is met: the height offset based on the first height is not within the adjustable range (hereinafter referred to as the first reporting condition); and the height offset based on the second height is not within the adjustable range (hereinafter referred to as the second reporting condition).

[0180] In this case, the estimation unit 46 may also, for example, Figure 16 In S60, it is determined whether at least one of the first and second reporting conditions is satisfied. Here, the estimation unit 46 may proceed to S80 and output an altitude deviation diagnosis if at least one of the first and second reporting conditions is satisfied. Alternatively, the estimation unit 46 may proceed to S70 and perform a load altitude adjustment if neither the first nor the second reporting condition is satisfied.

[0181] (Variation 3d)

[0182] The estimation unit 46 may also make a report only when both the first report condition and the second report condition are satisfied. In this case, the estimation unit 46 may also make a report only when both the first report condition and the second report condition are satisfied. Figure 16In S60, it is determined whether both the first and second reporting conditions are satisfied. Here, the estimation unit 46 may proceed to S80 and output an altitude deviation diagnosis if both the first and second reporting conditions are satisfied. Alternatively, the estimation unit 46 may proceed to S70 and perform a load altitude adjustment if at least one of the first and second reporting conditions is not satisfied.

[0183] [4. Other embodiments]

[0184] As mentioned above, although embodiment of this disclosure was described, this disclosure is not limited to the said embodiment, Various deformation|transformation can be made and it can be implemented.

[0185] (3a) In the above embodiment, the radar device 2 is configured so that its beam direction coincides with the direction of travel of the vehicle VH. However, the present disclosure is not limited thereto. For example, the radar device 2 may be configured so that its beam direction is tilted by a predetermined angle in the vertical or horizontal direction. Furthermore, the memory 42 may store a predetermined angle indicating the tilt of the beam direction.

[0186] (3b) The signal processing unit 4 and the method thereof described in the present disclosure may also be implemented by a dedicated computer provided by a processor and a memory programmed to execute one or more functions embodied by a computer program. Alternatively, the signal processing unit 4 and the method thereof described in the present disclosure may also be implemented by a dedicated computer provided by a processor composed of one or more dedicated hardware logic circuits. Alternatively, the signal processing unit 4 and the method thereof described in the present disclosure may also be implemented by one or more dedicated computers composed of a combination of a processor and a memory programmed to execute one or more functions and a processor composed of one or more hardware logic circuits. In addition, a computer program may also be stored as an instruction executed by a computer in a non-migratable tangible recording medium that can be read by a computer. The method for implementing the functions of each unit included in the signal processing unit 4 does not necessarily need to include software, and all of its functions may be implemented using one or more hardware.

[0187] (3c) It is also possible to implement multiple functions of one component in the above-mentioned embodiment by multiple components, or to implement one function of one component by multiple components. It is also possible to implement multiple functions of multiple components by one component, or to implement one function implemented by multiple components by one component. It is also possible to omit a portion of the components of the above-mentioned embodiment. It is also possible to add or replace at least a portion of the components of the above-mentioned embodiment with the components of other above-mentioned embodiments.

[0188] (3d) In addition to the above-mentioned signal processing unit 4, the present disclosure can also be implemented in various ways such as a vehicle control system 1, a program for making the signal processing unit 4 function, a non-migrating physical recording medium such as a semiconductor memory recording the program, a height offset estimation method, etc.

[0189] In the above embodiment, the vehicle VH corresponds to the mobile object, the signal processing unit 4 corresponds to the estimation device, and the memory 42 corresponds to the storage device. Furthermore, S10 corresponds to the processing of the acquisition unit, S20 corresponds to the processing of the extraction unit, S30 corresponds to the processing of the estimation unit and the calculation unit, and S35 corresponds to the processing of the estimation unit and the determination unit. S39 corresponds to the processing of the estimation unit and the compounding unit, S40, S42, and S44 correspond to the processing of the offset determination unit, and S380 corresponds to the processing of the correspondence acquisition unit. Furthermore, the height offset corresponds to the offset.

Claims

1. An estimation device, mounted on a mobile object, wherein: The estimation device comprises: an acquisition unit configured to acquire, for each of a plurality of reflection points detected by a radar device mounted on the mobile object, reflection point information, the reflection point information including at least a horizontal angle and a vertical angle, and a distance from the radar device to the reflection point, the horizontal angle and the vertical angle being azimuths with respect to the reflection point and being obtained based on a direction along a central axis of the radar beam, i.e., a beam direction; an extraction unit configured to extract at least one road surface reflection point detected by reflection on a road surface from among the plurality of reflection points based at least on the reflection point information; an estimating unit that estimates a height of the radar device mounted on the mobile object, namely, a device height, based on at least a road surface reflection point distance, namely, a distance from the radar device to the road surface reflection point; as well as The correspondence acquisition unit is configured to acquire the correspondence information from a storage device storing the correspondence information, wherein the correspondence information indicates a correspondence between a position of a road surface observed with the greatest frequency by the radar device installed at a plurality of predetermined heights, i.e., measurement heights, and the measurement heights. The above-mentioned estimation department shall have: The determination unit is configured to obtain an extraction frequency, determine a calculation position, and determine the measured height corresponding to the calculation position as the device height based on the corresponding information. The extraction frequency represents a value obtained by adding the number of times the road surface reflection point is extracted during a predetermined acquisition period according to the position of each road surface reflection point. The calculation position represents the position of the road surface reflection point with the largest extraction frequency.

2. The estimation device according to claim 1, wherein The above-mentioned estimation department shall have: a calculation unit configured to calculate the unknown parameter, that is, the device height, based on a relationship between the unknown parameter, the distance from the road surface reflection point, and the vertical angle, using the device height as an unknown parameter; and The composite unit estimates the device height based on the first height being the device height calculated by the calculation unit and the second height being the device height determined by the determination unit.

3. The estimation device according to claim 1 or 2, wherein: The estimation device comprises: The offset determination unit is configured to determine an offset indicating a magnitude of an offset in a height direction generated by the radar device.

4. The estimation device according to claim 3, wherein The offset determination unit acquires an initial height, which is a predetermined height when the radar device is mounted on the mobile object, and determines a difference between the initial height and the estimated device height as the offset.

5. The estimation device according to any one of claims 1, 2 and 4, wherein: The extraction unit determines whether the vehicle body of the moving object is in a stable state relative to the road surface, and extracts the road surface reflection point if it is determined that the vehicle body of the moving object is in a stable state relative to the road surface.

6. The estimation device according to claim 3, wherein The extraction unit determines whether the vehicle body of the moving object is in a stable state relative to the road surface, and extracts the road surface reflection point if it is determined that the vehicle body of the moving object is in a stable state relative to the road surface.

Images