METHOD FOR OPERATING A CAPACITIVE RAIN SENSOR OF A MOTOR VEHICLE, MEASUREMENT SIGNAL INTERFERENCE SUPPRESSION DEVICE, AND MOTOR VEHICLE COMPRISING SUCH A MEASUREMENT SIGNAL INTERFERENCE SUPPRESSION DEVICE

Abstract

The invention relates to a method for operating a capacitive motor vehicle rain sensor, which has an electrically conductive structure and which is designed to generate an analog measurement signal corresponding to a rain intensity and output same as an output signal, wherein the method has the steps of detecting at least one interference signal, which causes an interference with the analog measurement signal and leads to a measurement signal affected by interference, at least partly suppressing the interference of the measurement signal affected by interference in at least one signal processing step on the basis of the detected interference signal and an output of an at least partially interference-suppressed output signal. The invention also relates to a device for carrying out the method and to a motor vehicle comprising the device.

Claims

1.-8. (canceled)

9. A method for operating a capacitive rain sensor for a motor vehicle, the capacitive rain sensor having an electrically conductive structure, the capacitive rain sensor configured to produce an analog measurement signal corresponding to a rain intensity in at least one measurement, the method comprising the following steps: a) detecting at least one interference signal that causes interference with the analog measurement signal, wherein the at least one interference signal is an electromagnetic radio signal that is a radio transmission signal; b) at least partially suppressing the analog measurement signal using at least one signal processing technique, the at least one signal processing technique determined based at least in part on the detected at least one interference signal, the at least one signal processing technique comprising subtracting the detected at least one interference signal from the analog measurement signal; and c) outputting the at least partially suppressed analog measurement signal as an output signal; wherein the capacitive rain sensor comprises a first antenna formed by the electrically conductive structure, and measures a rain intensity, and wherein the electromagnetic radio signal is provided by the first antenna formed by the electrically conductive structure.

10. The method according to claim 9, wherein detecting the at least one interference signal comprises detecting, by at least one camera, a hand movement; and wherein the method further comprises: detecting, using at least one camera, at least one reference hand movement, and a change of a capacitance of the capacitive rain sensor caused by the at least one reference hand movement at a constant rain intensity; creating a correction rule for the at least one reference hand movement, wherein the correction rule compensates for the detected change in the capacitance of the capacitive rain sensor caused by the at least one reference hand movement; and assigning the detected hand movement to a reference hand movement based at least in part on a similarity criterion, the similarity criterion comprising at least one of a hand position or a hand size; wherein at least partially suppressing the analog the measurement signal comprises at least partially suppressing the analog measurement signal based at least in part on the correction rule created for the reference hand movement assigned to the detected hand movement.

11. The method according to claim 9, further comprising: transmitting the output signal via at least one of the first antenna formed by the electrically conductive structure of the capacitive rain sensor or a second antenna of the motor vehicle; and outputting, by a central receiving device, the output signal as current rain strength information.

12. The method according to claim 9, further comprising controlling a windshield wiper system of the motor vehicle based at least in part on the output signal.

13. The method according to claim 9, wherein the first antenna is configured to transmit or receive at least one of GSM or LTE mobile radio signals.

14. A motor vehicle comprising a capacitive rain sensor, the capacitive rain sensor having an electrically conductive structure, the capacitive rain sensor configured to produce an analog measurement signal corresponding to a rain intensity in at least one measurement, the motor vehicle further comprising one or more computing devices configured to: a) detect at least one interference signal that causes interference with the analog measurement signal, wherein the at least one interference signal is an electromagnetic radio signal that is a radio transmission signal; b) at least partially suppress the analog measurement signal using at least one signal processing technique, the at least one signal processing technique determined based at least in part on the detected at least one interference signal, the at least one signal processing technique comprising subtracting the detected at least one interference signal from the analog measurement signal; and c) output the at least partially suppressed analog measurement signal as an output signal; wherein the capacitive rain sensor comprises a first antenna formed by the electrically conductive structure, and measures a rain intensity, and wherein the electromagnetic radio signal is provided by the first antenna formed by the electrically conductive structure.

15. The motor vehicle according to claim 14, wherein detecting the at least one interference signal comprises detecting, using at least one camera, a hand movement; and wherein the one or more computing devices are further configured to: detect at least one reference hand movement, and a change of a capacitance of the capacitive rain sensor caused by the at least one reference hand movement at a constant rain intensity; create a correction rule for the at least one reference hand movement, wherein the correction rule compensates for the detected change in the capacitance of the capacitive rain sensor caused by the at least one reference hand movement; and assign the detected hand movement to a reference hand movement based at least in part on a similarity criterion, the similarity criterion comprising at least one of a hand position or a hand size; wherein at least partially suppressing the analog the measurement signal comprises at least partially suppressing the analog measurement signal based at least in part on the correction rule created for the reference hand movement assigned to the detected hand movement.

16. The motor vehicle according to claim 14, wherein the one or more computing devices are further configured to: transmit the output signal via at least one of the first antenna formed by the electrically conductive structure of the capacitive rain sensor or a second antenna of the motor vehicle; and wherein a central receiving device is configured to output the output signal as current rain strength information.

17. The motor vehicle according to claim 14, wherein the one or more computing devices are further configured to control a windshield wiper system of the motor vehicle based at least in part on the output signal.

18. The motor vehicle according to claim 14, wherein the first antenna is configured to transmit or receive at least one of GSM or LTE mobile radio signals.

Description

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

[0021] Exemplary embodiments of the present disclosure are described below. In the drawings:

[0022] FIG. 1 depicts a flow diagram of an example method according to example embodiments of the present disclosure;

[0023] FIG. 2 depicts a schematic representation of the measurement signal interference suppression device according to example embodiments of the present disclosure; and

[0024] FIG. 3 depicts a schematic representation of a motor vehicle with a measurement signal interference suppression device according to example embodiments of the present disclosure.

DETAILED DESCRIPTION

[0025] The exemplary embodiments explained below are preferred embodiments of the present disclosure. In the exemplary embodiments, the described components of the embodiments each constitute individual features of the embodiments of the present disclosure to be considered independently of one another, each of which independently further refines embodiments of the present disclosure, and are therefore also to be considered as part of the present disclosure individually or in a combination different from that shown. In addition, features of the present disclosure other than those already described may be added to the embodiments described.

[0026] In the drawings, elements having the same function are respectively provided with the same reference numerals.

[0027] FIG. 1 shows a schematic representation of the process. In this case, a capacitive rain sensor 10 measures a rainfall intensity 11. Information about the rainfall intensity 11 is output by the capacitive rain sensor 10 via an analog measurement signal 15. This analog measurement signal is disturbed by an interference signal 12. The interference signal 12 affects the capacitive rain sensor 10 on the one hand and is, on the other hand, detected by a detection device 13. The measurement signal 15 is disturbed by the interfering signal 12 and the interfering signal 12 detected by the detecting device 13 is respectively transmitted to a signal processing device 14. The signal processing device 14 uses the information on the detected interference signal 12 to suppress the interference-prone analog measurement signal 15. The signal processing device 14 outputs an at least partially interference-suppressed output signal 16 as a result.

[0028] FIG. 2 shows a schematic representation of a measurement signal interference device 20. As a capacitive rain sensor 10, the measurement signal interference device 20 has an electrically conductive structure 21. The latter transmits the analog measurement signal 15, which is disturbed by the interference signal 12, to the signal processing device 14. The detected interference signal 12 is supplied at an electrical input 22, so that the signal processing device 14 is available. The measurement signal interference suppression device 20 outputs the at least partially suppressed output signal 16 via an electrical output 23. The signal processing device 14 has a subtractor 24, a correction rule 25 and a similarity criterion 26 at its command.

[0029] FIG. 3 shows a schematic representation of a motor vehicle 30, which is equipped with a measurement signal interference suppression device 20. This device can be used to measure a rainfall intensity 11. The motor vehicle 30 has a camera 31, an interior antenna 32 and a motor vehicle antenna 33 as devices for detecting interference signals. An interference signal is an electromagnetic reception signal 34 or transmission signal 35, a mobile radio signal 36, which is transmitted by a mobile device 37 located in the motor vehicle 30 or a hand movement 38. The motor vehicle 30 has a signal processing device 14 for carrying out the signal processing step. The motor vehicle 30 can send information, for example the output signal 16, to an external server 39 via the transmission signal 35.

[0030] In one embodiment, the interfering signal 12 is an electromagnetic radio signal. The latter is forwarded to the signal processing device 14 through a detection device 13, such as an antenna, via the electrical input 22 of the measurement signal interference device 20. The capacitive rain sensor outputs an analog measurement signal 15, which is disturbed by the interference signal 12. The measurement signal 15 is also sent to the signal processing device 14. The subtractor 24 subtracts the detected interference signal 12 from the analog measurement signal 15 affected by interference. The interference-suppressed measurement signal 15 is issued as an output signal 16 via the electrical output 23. As a result, the output signal 16 is ideally completely interference-suppressed or at least partially interference-suppressed, so that the output signal 16 contains the information on the rain intensity 11 detected by the rain sensor 21 in the same way as the information the output signal 16 would contain if no interference signal 12 were present or if the deviation from this case were smaller than 10%.

[0031] In another exemplary embodiment, the interference signal 12 is provided by a hand movement 38. The hand movement 38 may, for example, be a hand movement by a driver of the motor vehicle 30. In this event, the hand movement 38 is detected by the camera 31 if it takes place at least in a predetermined proximity of the measurement signal interference device 20 and interferes with a measurement of the capacitive rain sensor 21. In this event, the interference signal 12 is detected by the camera 31 and is passed on to the signal processing device 14. In the signal processing step, the detected hand movement 38 is compared with other previously recorded hand movements via a similarity criterion 26 and a previously recorded hand movement is selected by means of the similarity criterion 26 whose interference effect on the analog measurement signal 15 has been detected and for which a correction rule 25, which describes the corrected interference of the analog measuring signal 15, has been created. The influence of a hand movement 38, which is recorded by the camera 31, on the measurement of the capacitive rain sensor 21 is thus known to the signal processing device 14 and can be compensated by means of the correction rules 25, so that the output signal 16 again represents the analog measurement signal 15 in the same way as the capacitive rain sensor 21 would represent the output 38 in the absence of the hand movement.

[0032] In a further embodiment, the interference signal 12 is supplied by a mobile radio signal 36 from a mobile device 37. The interference signal is detected by the indoor antenna 32 and supplies to the signal processing device 14. In another exemplary embodiment, the mobile radio signal of a car telephone is transmitted as a transmission signal 35 via the motor vehicle antenna 33, with the transmission signal 35 representing the interference signal 12. Due to the fact that the signal is transmitted by the motor vehicle antenna 33, it is already known for this process step, i.e., it does not have to be detected again separately, but can be made immediately available to the signal processing device 14. In another embodiment, the interference signal 12 is an electromagnetic reception signal 34, for example a mobile radio signal or a radio signal. This received signal 34 can either be detected by the electrically conductive structure 21, that is to say the capacitive rain sensor itself, and can be made available as an interference signal 12 of the signal processing device 14, or detected by the motor vehicle antenna 33. In this event, the motor vehicle antenna 33 is connected to the measurement signal interference device 20 of the motor vehicle 30.

[0033] In one exemplary embodiment, the measurement signal interference device 20 of the motor vehicle 30 corresponds to the measurement signal interference device 20 of FIG. 2, i.e., the signal processing device 14 and the capacitive rain sensor 21 are also made available in the measurement signal interference device 20. In another exemplary embodiment, the measurement signal interference device 20 has the electrically conductive structure 21 as well as the electrical input 22 and the electrical output 23. The signal processing device 14 is, however, made available in the motor vehicle 30, outside the measurement signal interference device 20. In doing so, the signal processing device 14 may, for example, be realized by an on-board computer of the motor vehicle 30.

[0034] The present disclosure shows how capacitive rain sensors, or their measured signal values, can be made robust against interference signals by the method according to the present disclosure. It is above all the advantage of a capacitive rain sensor, which is robust against interference signals, that it provides more accurate information about a current rainfall intensity than, for example, optical rain sensors. This is needed in order to use the rainfall intensity information of the capacitive rain sensor, for example for a weather service. The capacitive rain sensor using the process according to example embodiments of the present disclosure can therefore send very accurate rainfall intensity information to an external service, such as a weather service in real time. Interference signals which impair and distort the measurement result of the capacitive rain sensor, for example electromagnetic radio signals such as UMTS, GSM or LTE signals, are compensated by the method according to the present disclosure. The full potential of a capacitive rain sensor, which allows for a very accurate rain intensity measurement is thus provided. In doing so, the capacitive rain sensor can itself be configured as an antenna that sends or receives the interference signal, so that it is captured directly by the rain sensor and is known and can thus be filtered out of the measurement rather than entering into the rain measurement as undefined noise or interference. The advantages are a reduction in component costs by reducing complexity and a variety of alternatives. A capacitive rain sensor operated in this way only makes possible such a rain measurement when needed for certain applications, such as a host service for sending weather data to a backend. A capacitive rain sensor has the advantage that it can also be used to draw conclusions about residual amounts of salt in the water, for example, to describe how much salt is on a road in winter, so one knows whether salt should be scattered on the road or not in order to protect traffic during frost.

[0035] The examples show overall how a capacitive rain sensor can be operated via the present disclosure, so that it outputs such precise and exact rainfall intensity information, even in the presence of interference signals, that it can be used for services such as weather services. To accomplish this, the measuring signal of the capacitive rain sensor is processed as a function of the detected interference signal, so that the effect of the interference signal is compensated.