Sensor device for determining the environmental conditions of a vehicle, in particular a motor vehicle, and method for determining the position of the sun.

Abstract

Sensor device for determining the environmental conditions of a vehicle, in particular a motor vehicle, comprising at least one transmitter (2, 10) for emitting electromagnetic radiation, in particular infrared radiation, and at least three receivers (3, 8, 9) for receiving electromagnetic radiation, in particular infrared radiation, wherein at least one (3) of the at least three receivers (3, 8, 9) is assigned at least one of the transmitters (2, 10) for determining precipitation on at least one glass surface, in particular the windshield (1) of the motor vehicle, and wherein the at least three receivers (3, 8, 9) are oriented for receiving electromagnetic radiation from different spatial reception areas, wherein the spatial reception areas of at least one first (3) and at least one second (8) of the at least three receivers (3, 8, 9) are oriented substantially horizontally.wherein the spatial reception area of ​​at least one third (9) of the at least three receivers (3, 8, 9) is oriented substantially upwards , characterized by that the maxima of the spatial reception ranges of at least two (3, 8) of the at least three receivers (3, 8, 9) point in opposite directions, and that the maximum spatial reception range of a third (9) of the at least three receivers (3, 8, 9) is vertical to the axis of the spatial The receivers (3, 8) are aligned with the receivers pointing in opposite directions.

Description

[0001] The invention relates to a sensor device for determining the environmental conditions of a vehicle, in particular a motor vehicle, comprising at least two transmitters for emitting electromagnetic radiation, in particular infrared radiation, and at least three receivers for receiving electromagnetic radiation, in particular infrared radiation, wherein at least two receivers are each assigned to at least one transmitter for determining precipitation on at least one glass surface, in particular the windshield of a motor vehicle, and wherein at least three receivers are oriented to receive electromagnetic radiation from different angular ranges, wherein the spatial reception ranges of at least one first and at least one second of the at least three receivers are oriented substantially horizontally.wherein the spatial reception area of ​​at least one third of the at least three receivers is essentially oriented upwards.

[0002] Furthermore, the invention relates to a vehicle with a sensor device according to the invention and to a method for determining the position of the sun using the sensor device according to the invention.

[0003] Methods and devices for determining environmental conditions are used in a wide variety of vehicles. These environmental conditions can include, for example, weather influences such as the wetting state of the windshield or the position of the sun. Optical sensor devices can be used to determine the wetting state of the windshield. In such devices, an infrared signal is coupled into the windshield, and after the infrared radiation travels a defined distance within the windshield, the proportion of total internal reflections in the windshield can be determined based on the portion of the signal that is coupled out again. The proportion of total internal reflections is influenced by the wetting of the windshield, for example, by water.Besides the degree of wetting of the windshield, the position of the sun relative to the vehicle is an important parameter, as the sun's position can be used as a parameter in control programs for systems such as air conditioning. Combined rain and light sensors are often used to determine these parameters, employing separate receivers for measuring the light level in addition to the transmitters and receivers for rain detection.

[0004] For example, German patent DE 10 2009 007 521 B4 describes a method for determining the sun's position for a motor vehicle's air conditioning system. This method uses solar radiation sensors, one of which is tilted at a specific angle to the right and the other at a specific angle to the left relative to the vehicle's longitudinal direction. These sensors determine the angle of the sun's position relative to the vehicle's longitudinal direction and the intensity of the solar radiation. During a rotation of the sensor around a vertical axis, the intensity of the solar radiation is repeatedly measured by both the left and right sensors, and a normalized difference is calculated from these intensity values. The sun's elevation is then determined from a stored elevation characteristic curve of the sensor relative to this normalized difference.The azimuth angle is determined from a stored elevation characteristic field of the sensor, based on the determined elevation of the sun and the current normalized difference.

[0005] German patent DE 299 24 958 U1 relates to a sensor with at least one transmitter and one receiver. A windshield lies between them in the measurement path, influencing the propagation of light between them. A receiver output signal, used to control the windshield wipers, changes when the windshield becomes wet, particularly when moistened by precipitation. At least one receiver receives light at ambient intensity and is used to control a vehicle lighting system.

[0006] EP 1 514 750 A2 relates to a combined sensor arrangement for detecting ambient light and moisture on a surface. A radiation emitter emits radiation onto a surface such that the radiation is essentially reflected at a reflective point on the surface towards a radiation receiver. Depending on the intensity of the reflected radiation, the degree of moisture on the surface can be determined. A second sensor, comprising a light sensor, is provided for determining the intensity of ambient light in order to measure the intensity of light rays from a specific direction. The sensor arrangement is housed in a casing, with the second sensor being shielded from the radiation emitted by the radiation emitter by a baffle.A disadvantage of the known devices and methods is that they require the use of sun position sensors specifically designed for this purpose. These additional sensors increase the number of components required and raise the cost of the device.

[0007] The invention is based on the objective of proposing a sensor device of the type mentioned above in which no sensor elements specifically provided for determining the position of the sun are necessary.

[0008] This problem is solved using a sensor device with the features of claim 1, a vehicle with the features of claim 5, and a method with the features of claim 7.

[0009] In a sensor device for determining the environmental conditions of a vehicle, in particular a motor vehicle, comprising at least two transmitters for emitting electromagnetic radiation, in particular infrared radiation, and at least three receivers for receiving electromagnetic radiation, in particular infrared radiation, wherein at least one of the at least three receivers is assigned at least one of the transmitters for determining precipitation on at least one glass surface, in particular the windshield, of the motor vehicle, and wherein at least three receivers for receiving electromagnetic radiation are configured from mutually distinct spatial reception areas, wherein the spatial reception areas of at least one first and one second receiver are essentially horizontally oriented, and wherein the spatial reception area of ​​at least one third receiver is essentially upwards,The invention provides that the maxima of the spatial reception areas of at least two of the at least three receivers point in opposite directions, and that the maximum of the spatial reception area of ​​a third of the at least three receivers is aligned vertically to the axis of the spatial reception characteristics of the oppositely oriented receivers. The sensor device has at least three receivers for electromagnetic radiation, in particular for infrared radiation. The receivers can be, in particular, photodiodes. The spatial reception areas, i.e., the spatial angular ranges from which the receivers can detect radiation from two receivers, are horizontally oriented to different sides. In particular, the receivers can be arranged on different sides of a vehicle longitudinal axis, in particular the vehicle's central axis. The areas arranged laterally next to the vehicle's central axis are theThe sensor device is located in the driver's area and the passenger's area. Preferably, it is mounted on the windshield of a motor vehicle. At least the first and second receivers are equipped with transmitters for emitting infrared radiation. Infrared radiation can be coupled into the windshield by a transmitter. Total internal reflections within the glass of the windshield transmit the infrared radiation. Wetting of the windshield, for example with rainwater, reduces the proportion of total internal reflections, thus partially coupling the infrared radiation out of the windshield. After a defined test path along the windshield, the receivers can detect the totally reflected portion of the infrared radiation. Determining the proportion of totally reflected infrared radiation allows for an assessment of the degree of wetting of the windshield.These parameters can be used, for example, for the automatic control of a windshield wiper system. Two rain measurement paths can be configured: one between a first receiver and a first transmitter, and the other between a second transmitter and a second receiver. These paths can be oriented horizontally along the windshield, i.e., perpendicular to, and especially at right angles to, the vehicle's longitudinal axis. For example, the first receiver can be oriented towards the passenger side, and the second receiver can be oriented towards the driver's side. The spatial reception areas of the two receivers can therefore point in different directions. The corresponding transmitters are arranged so that the radiation coupled into the windshield lies within the reception area of ​​the respective receiver. In addition to the first and second receivers, the sensor device has a third receiver. This receiver canThe third receiver is also assigned to a transmitter and thus, in conjunction with the transmitter, forms a measuring section for precipitation on the windshield. The third receiver is arranged vertically to the measuring sections between the first and second receivers and their assigned transmitters. Specifically, when the sensor device is mounted on a windshield, the receiver can be positioned above or below the first and second receivers and their assigned transmitters. The third receiver can also be positioned vertically below a transmitter. The spatial reception area of ​​the third receiver is oriented upwards. Therefore, the three receivers are oriented in different directions. In addition to forming three measuring sections for determining precipitation on the windshield, the three receivers can also be used to determine the position of the sun. The receivers are designed to detect infrared radiation.This radiation is emitted by the sun, allowing the sun's position to be determined by detecting infrared radiation from three different directions. Preferably, the three receivers, particularly the photodiodes, have identical spectral sensitivities. Each receiver outputs an irradiance value. By comparing and normalizing the three irradiance signals, the current position of the sun can be calculated. Therefore, by using three receivers oriented in different directions, it is possible to determine both the wetting state of the windshield and the position of the sun.

[0010] The maximum spatial reception characteristic of a receiver is defined as the solid angle within which the receiver exhibits its maximum sensitivity and thus outputs the highest irradiance value under appropriate illumination. By arranging a first and a second receiver with maxima of the spatial reception characteristic pointing in opposite directions, radiation incident from, for example, the driver's side and the passenger's side of a vehicle can be detected. The maximum of the spatial reception characteristic of a third receiver can be oriented vertically to the maxima of the spatial reception characteristics of the first and second receivers. This vertical orientation of the third receiver to the first and second receivers allows infrared radiation to be detected from three different directions.In particular, this allows the passenger side, the driver's side, and the area facing away from any surface driven over by the vehicle—i.e., the upward-facing area—to be detected. By recording irradiance values ​​from three spatial directions, the sun's position relative to the vehicle can be determined.

[0011] In a further development of the invention, the receivers exhibit at least nearly identical spectral sensitivity. In order to calculate the sun's position from, for example, irradiance values ​​from three different spatial directions, the receivers must, for reasons of comparability and normalization, have the same spectral sensitivity so that they output the same irradiance value under the same irradiation conditions.

[0012] In a further development of the invention, the sensor device comprises at least one coupling element for coupling the electromagnetic radiation from a transmitter into a glass surface and at least one extraction element for extracting the electromagnetic radiation from a glass surface. The coupling elements can, in particular, be optical components that enable the infrared radiation from the transmitter to be introduced into the windshield of a vehicle. For example, the coupling elements can be lens-shaped components arranged between the transmitters and the windshield. The extraction elements can also be lens-shaped components that, after the infrared radiation emitted by the transmitter has passed through a measuring section in the windshield, extract the infrared radiation for detection by a receiver.The coupling and coupling elements are required for determining precipitation on the windshield. The optical components have no function while the sun's position is being determined via the receivers.

[0013] In a further development of the invention, at least one transmitter is assigned two receivers. For example, a transmitter can be designed such that the infrared signal coupled into the windshield by the transmitter can be received by a receiver arranged horizontally to the transmitter and a receiver arranged vertically to the transmitter. Thus, two measuring paths for determining precipitation on the windshield are formed between the transmitter and the two receivers.

[0014] In a vehicle with at least one windshield and at least one sensor device according to the invention, it is essential to the invention that the sensor device is arranged on the windshield, that at least one of the receivers is oriented towards the driver's side of the vehicle, that at least one of the receivers is oriented towards the passenger side of the vehicle, and that at least one of the receivers is oriented away from the road surface on which the vehicle is moving. The sensor device is arranged on the windshield. A receiver for receiving electromagnetic radiation, in particular infrared radiation, is arranged facing the passenger side. In particular, the receiver can be oriented such that the maximum of the spatial reception characteristic is horizontal, i.e., perpendicular to the longitudinal axis of the vehicle.A second receiver is preferably positioned facing the driver's side. The maximum of the reception characteristic, i.e., the angle at which the receiver exhibits its highest sensitivity, is also oriented transversely to the vehicle's longitudinal axis. Accordingly, the transmitters are positioned on the axes of the maxima of the spatial reception characteristics of the first and second receivers. The transmitters are designed to emit infrared radiation. Infrared radiation can be coupled into the windshield by the transmitters and detected by the associated receivers at a distance that defines the measuring range. The windshield's wetting state can be calculated from the proportion of radiation totally reflected within the windshield. Preferably, a first receiver and a first transmitter are positioned at the same height relative to the ground on which the vehicle is moving.A second transmitter and a second receiver are also arranged on a horizontal plane at the same height. For example, a third receiver can be assigned to the second transmitter. This third receiver is positioned vertically below the transmitter, along the surface of the windshield, relative to the ground. Preferably, the two imaginary lines connecting the transmitter and the two assigned receivers form a right angle. Thus, two measuring paths are formed between the transmitter and the two receivers for determining the wetting state of the windshield. The first two receivers are oriented towards the passenger side and the driver's side of the vehicle, preferably on both sides of the vehicle's longitudinal axis. The third receiver is oriented away from the ground on which the vehicle is moving. Therefore, the third receiver is oriented upwards, for example, towards the sky.The spatial reception characteristics of the three receivers thus point in three different directions. In addition to receiving infrared radiation emitted by the transmitters, the receivers can also detect infrared radiation from ambient light, such as infrared radiation emitted by the sun. By recording an irradiance value with each of the three receivers, the sun's position can be determined. In this configuration, the receivers can therefore be used both to determine the degree of wetting of the windshield, i.e., as a rain sensor, and to determine the sun's position. No additional components are required. This results in a reduced component list and thus cost savings compared to using separate rain and light sensors.

[0015] In a further development of the invention, the receiver, oriented away from the ground surface, is arranged along the surface of the windshield, above or below the transmitters with respect to the ground surface. The two receivers oriented to the sides, particularly to the passenger side and the driver's side, are each assigned to a transmitter. Preferably, a transmitter-receiver pair is arranged on a horizontal axis at a height above the ground surface. The connecting lines between a receiver and a transmitter are arranged transversely to the longitudinal axis of the vehicle. A third receiver, which is oriented away from the surface being driven over, i.e., upwards towards the sky, is positioned above or below the two horizontally oriented receiver-transmitter pairs when viewed from the ground surface. The windshield of a vehicle is usually inclined against the direction of travel.For example, the upward-facing receiver can be positioned further towards the ground along the surface of the windshield than the other two receiver-transmitter pairs. This arrangement ensures unobstructed transmission of infrared radiation from the vehicle's surroundings, such as from the sun, to the receiver. The receivers thus enable the reception of infrared radiation from three directions.

[0016] Another aspect of the invention relates to a method for determining the position of the sun using a sensor device according to any one of claims 1-4, wherein at least three receivers each detect at least one irradiance value of the ambient light, the maximum value of the detected irradiance values ​​is determined, and the side of the vehicle facing the sun is inferred from the maximum irradiance value. The three receivers of the sensor device are oriented in different directions. Preferably, one receiver is oriented towards the passenger side of the vehicle, one receiver towards the driver's side of the vehicle (i.e., on both sides of the vehicle's central axis), and one receiver is oriented away from the ground on which the vehicle is moving (e.g., towards the sky). Each of these three receivers determines a value of the irradiance.To ensure comparability of the irradiance values, the receivers have the same spectral sensitivity. To determine the sun's position from the recorded irradiance values, the maximum value of the three recorded irradiance readings is determined. By identifying which of the three receivers output the highest irradiance value, the direction from which the sun is shining on the vehicle can be deduced.

[0017] In a further development of the method, the irradiance values ​​are recorded sequentially by the receivers. The receivers are designed both to determine the wetting of the windshield with a liquid and to determine the position of the sun. Preferably, the irradiance values ​​of the ambient light are recorded while the wetting state is not determined. While the irradiance values ​​of the ambient light are being recorded by the receivers, no infrared radiation is emitted by the transmitters. The irradiance values ​​are recorded sequentially by the three receivers. For example, the irradiance value on the passenger side can be determined first, followed by the irradiance value on the driver's side, and then the irradiance value is determined by the receiver facing upwards.The determined radiation intensity values ​​can be processed by an evaluation unit.

[0018] In a further development of the invention, the irradiance values ​​determined by the two substantially horizontally oriented receivers are normalized by dividing them by the determined maximum irradiance value. The smaller of the two normalized irradiance values ​​is subtracted from the larger of the two normalized irradiance values. The arccosine is calculated from the result of this subtraction and assigned to the azimuth angle of the sun's position. To determine the sun's position, in particular its azimuth angle, the maximum value of the two horizontally oriented receivers is determined. The two irradiance values ​​are normalized by dividing them by the determined maximum value. If the irradiance values ​​of the two receivers are equal, the sun is directly in the direction of travel.The smaller of the two normalized irradiance values ​​is subtracted from the larger, maximum irradiance value, which is normalized to 1. The result of this subtraction corresponds to the adjacent side of the triangle used to determine the azimuth, while the vector representing the sun's position forms the hypotenuse. By calculating the inverse function of the cosine, i.e., the arccosine, the azimuthal angle of the sun's position relative to the sensor can be determined.

[0019] In a further development of the method, a vector is determined from each of the irradiance intensity signals measured by the two essentially horizontally oriented receivers. A sum vector is formed from these two vectors, and the magnitude of the resulting sum vector is compared with the irradiance intensity signal measured by the essentially upwardly oriented receiver. The measured irradiance intensity values ​​are normalized, and the smaller of the two normalized irradiance intensity values ​​is subtracted from the larger of the two normalized irradiance intensity values. The arccosine is calculated from the result of this subtraction and assigned to the elevation angle of the sun. Vectors can be determined from the measured signals of the two essentially horizontally oriented receivers. A sum vector can be formed from these two vectors.To determine the elevation angle, the magnitude of the sum vector is compared with the signal from the receiver, which is essentially oriented upwards. The maximum values ​​of the irradiance resulting from the sum vector and the irradiance measured by the upward-oriented receiver are then determined.

[0020] For normalization, the irradiance values ​​are divided by the maximum irradiance value. The smaller of the two normalized irradiance values ​​is subtracted from the larger of the two normalized irradiance values, and the arccosine is calculated from the result of this subtraction. The arccosine corresponds to the elevation angle of the sun relative to the sensor device.

[0021] The invention will now be explained in more detail with reference to a preferred embodiment shown in the drawing. Specifically, the schematic representations in: Fig. 1: an arrangement of transmitter and receiver for determining an irradiance value and the degree of wetting of a windshield; and Fig. 2: an arrangement of three measuring sections for determining the degree of wetting of a windshield and the position of the sun.

[0022] In Fig. Figure 1 shows a measuring section for determining the precipitation on a vehicle's windshield 1. The measuring section consists of a transmitter 2 and a receiver 3. An input element 4 is arranged between the transmitter 2 and the windshield 1, through which the infrared radiation emitted by the transmitter 2 can be coupled into the windshield 1. Similarly, an output element 5 is arranged between the receiver 3 and the windshield 1, through which the coupled infrared radiation is coupled out to the receiver 3. Infrared radiation emitted by the transmitter 2 can be transmitted through the windshield 1 by total internal reflection. When the windshield 1 becomes wet, for example with rainwater, total internal reflection occurs not only within the windshield 1, but the infrared radiation is also partially coupled out along the measuring section.The receiver 3 can detect the proportion of total internal reflections in the windshield 1 or the proportion of emitted light, from which the wetting state of the windshield 1 can be determined. In addition to determining the wetting state, the receiver 3 can also be used to determine the position of the sun. The infrared radiation 7 emitted by the sun 6 is detected by the receiver 3. The detection of the infrared radiation 7 emitted by the sun 6 preferably takes place while no infrared radiation is emitted by the transmitter 2. By using several receivers 3 oriented in different directions, it is possible to determine the position of the sun.

[0023] In Fig.Figure 2 shows an arrangement of three measuring sections for determining the position of the sun. Three receivers 3, 8, 9 are assigned to two transmitters 2, 10. Preferably, the arrangement is mounted on the windshield 1 of a vehicle. Measuring sections are formed in this arrangement between transmitter 2 and receiver 3, between transmitter 10 and receiver 8, and between transmitter 10 and receiver 9. The measuring section 11 between transmitter 2 and receiver 3, as well as the measuring section 12 between transmitter 10 and receiver 8, are horizontally oriented. In particular, the measuring sections 11 and 12 are oriented transversely to a longitudinal axis of the vehicle. Receiver 3 faces the passenger side, while receiver 8 faces the driver's side. A measuring section 13 is formed between transmitter 10 and receiver 9, running transversely to the measuring sections 11 and 12.Along the windshield 1, the receiver 9 is positioned below the transmitter 10. The receiver 9 is oriented away from the road surface on which the vehicle is moving. Due to the angle of the windshield 1, the upward-facing reception field of the receiver 9 is not obstructed by the transmitters 2, 10 or the other receivers 3, 8. The orientation of the receivers 3, 8, and 9 enables the detection of infrared radiation from three different directions relative to the vehicle. The arrangement of the transmitters and receivers relative to each other allows for the determination of the windshield 1's wetness level as well as the sun's position without the need for additional components.

[0024] All features mentioned in the foregoing description and in the claims can be combined in any selection with the features of the independent claims. The disclosure of the invention is therefore not limited to the described or claimed combinations of features; rather, all combinations of features meaningful within the scope of the invention are to be considered disclosed.

Claims

[1] Sensor device for determining the environmental conditions of a vehicle, in particular a motor vehicle, comprising at least one transmitter (2, 10) for emitting electromagnetic radiation, in particular infrared radiation, and at least three receivers (3, 8, 9) for receiving electromagnetic radiation, in particular infrared radiation, wherein at least one (3) of the at least three receivers (3, 8, 9) is assigned at least one of the transmitters (2, 10) for determining precipitation on at least one glass surface, in particular the windshield (1) of the motor vehicle, and wherein the at least three receivers (3, 8, 9) are oriented to receive electromagnetic radiation from different spatial reception areas, wherein the spatial reception areas of at least one first (3) and at least one second (8) of the at least three receivers (3, 8, 9) are oriented substantially horizontally,wherein the spatial reception area of ​​at least one third (9) of the at least three receivers (3, 8, 9) is oriented substantially upwards, characterized by is, that the maxima of the spatial reception ranges of at least two (3, 8) of the at least three receivers (3, 8, 9) point in opposite directions, and that the maximum spatial reception range of a third (9) of the at least three receivers (3, 8, 9) is vertical to the axis of the spatial The receivers (3, 8) are aligned with the receivers pointing in opposite directions. [2] Sensor device according to claim 1, characterized by that the at least three receivers (3, 8, 9) have at least nearly identical spectral sensitivity. [3] Sensor device according to one of claims 1 or 2, characterized by, that the sensor device has at least one coupling element (4) for coupling the electromagnetic radiation of one of the transmitters (2, 10) into a glass surface and at least one coupling element (5) for coupling the electromagnetic radiation out of a glass surface. [4] Sensor device according to any one of claims 1 to 3, characterized by , that at least one of the senders (2, 10) is assigned to two of the at least three receivers (3, 8, 9). [5] Vehicle with at least one windshield (1) and with at least one sensor device according to one of the preceding claims, characterized by , that the sensor device is arranged on the windshield (1), that at least one (8) of the at least three receivers (3, 8, 9) is oriented towards the driver's side of the vehicle, that at least one (3) of the at least three receivers (3, 8, 9) is oriented towards the passenger side of the vehicle and that at least one (9) of the at least three receivers (3, 8, 9) is oriented away from the ground surface on which the vehicle is moving. [6] Vehicle according to claim 5, characterized by , that the receiver (9), which is oriented away from the ground surface, is arranged along the surface of the windshield (1) with reference to the ground surface above or below the at least one transmitter (2, 10). [7] Method for determining the position of the sun with a sensor device according to one of claims 1-4, wherein at least one irradiance intensity value of the ambient light is detected with the at least three receivers (3, 8, 9), wherein the maximum value of the detected irradiance intensity values ​​is determined, wherein the side of the vehicle facing the sun (6) is inferred from the maximum irradiance intensity value. [8] Method according to claim 7, characterized by that the radiation intensity values ​​are recorded sequentially by the at least three receivers (3, 8, 9). [9] Method according to one of claims 7 or 8, characterized by, that the irradiance values ​​determined with the two essentially horizontally oriented receivers (3, 8) are divided by the determined maximum irradiance value for normalization, that the smaller of the two normalized irradiance values ​​is subtracted from the larger of the two normalized irradiance values, that the arccosine is formed from the result of the subtraction, and that the arccosine is assigned to the azimuth angle of the sun's position. [10] Method according to any one of claims 7 to 9, characterized by, that a vector is determined from each of the irradiance intensity signals measured with the two substantially horizontally oriented receivers (3, 8), that a sum vector is formed from the two vectors, that the magnitude of the resulting sum vector is compared with the irradiance intensity signal measured with the substantially upwardly oriented receiver (9), that the measured irradiance intensity values ​​are normalized, that the smaller of the two normalized irradiance intensity values ​​is subtracted from the larger of the two normalized irradiance intensity values, that the arccosine is formed from the result of the subtraction, and that the arccosine is assigned to the elevation angle of the sun's position.

Images