RADAR SENSING OF VEHICLE OCCUPANCY

Abstract

A method for sensing occupancy status within an automotive vehicle uses a radar sensor system having an antenna system, at least one sensor and processing circuitry. The method comprises: illuminating, using the antenna system, at least one occupiable position within the vehicle with an outgoing radar signal; receiving, using at least one sensor, at least one sensor signal reflected as a result of the outgoing radar signal; obtaining accelerometer data value from at least one accelerometer, the accelerometer data containing information regarding vibration or motion of the automotive vehicle and supplying the accelerometer data to the processing circuitry; and operating the processing circuitry for generating, based on the at least one sensor signal and on the accelerometer data, one or more occupancy status signals, the occupancy status signal indicating a property related to the at least one occupiable position.

Claims

1. A method for sensing occupancy status within an automotive vehicle using a radar sensor system, the radar sensor system comprising an antenna system, at least one sensor and processing circuitry, the method comprising illuminating, using the antenna system, at least one occupiable position within the vehicle with an outgoing radar signal; receiving, using at least one sensor, at least one sensor signal reflected as a result of the outgoing radar signal, obtaining accelerometer data value from at least one accelerometer, said accelerometer data containing information regarding vibration or motion of said automotive vehicle and supplying said accelerometer data to said processing circuitry; operating the processing circuitry for generating, based on the at least one sensor signal and on the accelerometer data, one or more occupancy status signals, the occupancy status signal indicating a property related to said at least one occupiable position, wherein said generating one or more occupancy status signals comprises applying, based on said accelerometer data, offset removal to said sensor signal to generate a modified signal; and generating said one or more occupancy status signals based on the modified signals.

2. The method of claim 1, wherein the one or more occupancy status signals comprise an occupant detection signal, indicating whether or not an occupant is present in the occupiable position, an occupant classification signal, indicating a classification for an occupant present in the occupiable position, and/or an occupant vital signs signal, indicating the extent to which vital signs are exhibited in the occupiable position or by an occupant in the occupiable position.

3. A radar sensor system for sensing occupancy status within an automotive vehicle, the system comprising: an antenna system for illuminating at least one occupiable position within the vehicle with an outgoing radar signal; at least one sensor for receiving at least one sensor signal reflected as a result of the outgoing radar signal, and a processing circuitry coupled to the at least one sensor, the processing circuitry being operable for obtaining accelerometer data from at least one accelerometer, said accelerometer data containing information regarding vibration or motion of said automotive vehicle, and for generating, based on the at least one sensor signal and on the accelerometer data, one or more occupancy status signals, the occupancy status signal indicating a property related to said at least one occupiable position, wherein said generating one or more occupancy status signals comprises applying, based on said accelerometer data, offset removal to said sensor signal to generate a modified signal; and generating said one or more occupancy status signals based on the modified signals.

4. The radar sensor system according to claim 3, wherein the one or more occupancy status signals comprise an occupant detection signal, indicating whether or not an occupant is present in the occupiable position, an occupant classification signal, indicating a classification for an occupant present in the occupiable position, and/or an occupant vital signs signal, indicating the extent to which vital signs are exhibited in the occupiable position or by an occupant in the occupiable position.

5. The radar sensor system according to claim 3, wherein said at least one accelerometer is a dedicated accelerometer and forms an integral part of said radar sensor.

6. The radar sensor system according to claim 3, wherein said at least one accelerometer is an accelerometer associated to existing vehicle components, such as an airbag control unit accelerometer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] An embodiment of the invention will now be described by way of reference example to the accompanying drawing, in which FIG. 1 is a schematic diagram of a radar sensor for occupant sensing.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0028] Radar sensing within a complex environment like the interior of a car cabin is very challenging and the algorithm differs much from those for exterior radar sensing.

[0029] The advantage of radar systems is that in contrast to passive camera systems the radar system operates also in the night as it illuminates actively the scene. Active camera systems need an illumination in the light spectrum which can be visible for the human eye (compare to the glooming of infrared cameras). Radar systems work in the microwave range which is completely invisible for the human eye. In addition it penetrates into materials and can transmit through. So the integration behind plastic covers and textiles as well is possible while camera based systems need an opening to look through.

[0030] In one embodiment, the radar detection system has nearly fixed and constant antenna lobes over the whole frequency range from 24.00 GHz up to 24.25 GHz; however, the invention is not restricted to this frequency range. The frequency can be lower, higher or overlapping. Furthermore the invention applies to both conventional Doppler radars (CW-radars) and or FMCW radars.

[0031] The radar sensor system for sensing occupancy status within an automotive vehicle shown in Fig. comprises an antenna system (Tx) for illuminating at least one occupiable position within the vehicle with an outgoing radar signal. At least one sensor (Radar Sensor) is receiving (via RX) at least one sensor signal reflected as a result of the outgoing radar signal. A processing circuitry (Interior Radar Algorithm) is coupled to the radar sensor.

[0032] At least one accelerometer is operatively coupled to the processing circuitry. The accelerometer may be an existing accelerometer in the car, such as an accelerometer of the airbag control unit, or a dedicated accelerometer embedded into the radar sensor. It will be noted that several (different) accelerometers may be read out by the processing circuitry.

[0033] The processing circuitry is configured and operable for obtaining accelerometer data containing information regarding vibration or motion of said automotive vehicle from the accelerometer and for generating, based on the at least one sensor signal and on the accelerometer data, one or more occupancy status signals (CPS), the occupancy status signal indicating a property related to said at least one occupiable position.

[0034] Due to the use of the accelerometer data, external influences, vibrations and vehicle motion may be filtered out and the classification of the occupancy status is improved.