CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to European Patent Application No. 19177749.9, filed on May 31, 2019.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to systems and methods of operating partially and fully-automated or autonomous vehicles.

Such a method is useful especially in the field of human-assisted or autonomous vehicles using sensors for obstacle detection and avoidance, to navigate safely through its environment.

BACKGROUND OF THE DISCLOSURE

Partially and fully-automated or autonomous vehicles have been proposed.

The document US2016/0231746 discloses systems and methods for operating an automated vehicle such as an autonomous vehicle including an autonomous guidance system, a method of automatically controlling an autonomous vehicle based on electronic messages from roadside infrastructure or other-vehicles, a method of automatically controlling an autonomous vehicle based on cellular telephone location information, pulsed LED vehicle-to-vehicle (V2V) communication system, a method and apparatus for controlling an autonomous vehicle, an autonomous vehicle with unobtrusive sensors, and adaptive cruise control integrated with a lane keeping assist system. The systems and methods may use information from radar, LIDAR, a camera or vision/image devices, ultrasonic sensors, and digital map data to determine a route or roadway position and provide for steering, braking, and acceleration control of a host vehicle.

However, the systems and methods necessary to control the vehicle can be improved.

In particular, in certain specific driving situations, such as crossroads or work area where road work fences are installed, usual sensors like radar and camera cannot detect non-visible vehicles moving in the vehicle's environment and maybe towards the vehicle. More generally, non-visible vehicles are caused by obstacles between the sensing vehicle concerned and the non-visible vehicle, such as a parked car, a wall, metal plates, road work fences or any other object obstructing the view between the two vehicles.

Risks of collision increase if an automated vehicle is not able to detect another (non-visible) vehicle on a crossroad or in a work area, reducing the safety of Advanced Driver Assistance System (ADAS) or autonomous driving vehicle.

SUMMARY

A first aspect of the disclosure relates to a method for detecting non-visible vehicles in a driven vehicle's environment, wherein each vehicle is equipped with at least one proximity sensor. The method includes: screening, by a receiver of the proximity sensor, any incoming proximity signal capable of propagating through the air along a non-linear path; receiving an incoming proximity signal coming from a non-visible vehicle; processing the received proximity signal to detect the non-visible vehicle; and warning a driver and/or an advanced driver-assistance system about the detected non-visible vehicle.

By using proximity sensors screening and receiving proximity signals propagating in the air along a non-linear path, it allows an equipped vehicle to receive these proximity signals despite the presence of some obstacles in between the driven vehicle and another vehicle non-visible either for the driver or for the cameras and radar detectors of the driven vehicle. These proximity signals are capable of propagating through the air along a non-linear path contrary to a light wave coming from any light sensor. It therefore allows detection of non-visible vehicles located behind an obstacle and in turn warning the driver or the Advanced Driver Assistance System (ADAS) in order to prevent a risk of collision between both vehicles.

Advantageously, the method comprises for each driven vehicle a preliminary step of: emitting, by an emitter of the proximity sensor, a proximity signal capable of propagating through the air along a non-linear path.

In this manner, all equipped driven vehicles are able to be detected by other equipped non-visible driven vehicles. A non-linear path is one without reflective surfaces so that a light beam would not be able to reach non-visible vehicles from the driven vehicle.

The emitted proximity signal in some embodiments is a periodic pulse, such as a proximity signal emitted every 100 ms.

Using a periodic pulse reduces the power consumption of the proximity sensor compared to a continuous signal. A frequency of 10 Hz is high enough to allow rapid detection of a non-visible vehicle and to prevent a risk of collision.

The at least one proximity sensor in some embodiments is an ultrasonic sensor, the proximity signal is an ultrasonic signal and the screening step is a listening step. There may be a plurality of ultrasonic sensors which are the parking sensors of the vehicle. The ultrasonic signal can be a periodic pulse emitted with maximum power of the parking sensor.

The use of ultrasounds prevents any disturbance to the driver and in general to road users. When driving, parking sensors are not used and are therefore available for other purposes such as being used as proximity sensors to detect (non-visible) vehicles in the surroundings. In order to benefit from the maximum range to detect non-visible vehicle, the ultrasonic signal is emitted with maximum power. Further, the use of ultrasounds does not affect the efficiency of the detection whatever the weather conditions are.

Using the parking sensors of existing park assist option enables to implement the method on the existing automotive fleet of vehicles equipped with such ultrasonic park assist. Usually, the ultrasonic park assist uses the same frequency, namely 40 KHz, so that other equipped vehicles can detect the emitted pulse. Compared to the standard usage of the ultrasonic park assist, the present method increases (doubles) the detection distance because one equipped vehicle emits the pulse and another receives it.

Advantageously, the processing step of the received ultrasonic signals further analyses the Doppler effect to determine the distance and speed of the detected non-visible vehicle.

By analysing the Doppler effect of the incoming ultrasonic signals, the processor can retrieve a variable period of the emitted pulses with will depend on the distance of the emitter of the non-visible vehicle as well as its speed.

The ultrasonic signals can be modulated in amplitude and the processing step further analyses the amplitude modulation to determine any speed variation of the detected non-visible vehicle.

Modulation of the amplitude of the ultrasonic signal allows to the processor to determine if any speed variation of the detected non-visible vehicle.

The warning step in some embodiments further evaluates and warns about a risk of collision with the detected non-visible vehicle.

Depending on the distance and speed of the detected non-visible vehicle the warning unit may adapt the warning signal sent to the driver and/or the ADAS. In case of amplitude modulation of the incoming signals, the processor also detects the variation of the speed and the warning unit may further adapt the warning signal.

The receiver may screen any incoming proximity signal either continuously or when the emitter is not emitting.

To avoid interference between the receiver(s) and the emitter(s) of the proximity sensor(s) of an equipped vehicle, the receiver is inactive during emission of the proximity signal.

In some embodiments, each vehicle is equipped with at least one light sensor and the method includes: detecting visible vehicles in the vehicle's environment by the at least one light sensor; comparing all detected vehicles by both the light sensor and the proximity sensor; and determining the detected vehicles by the proximity sensor which are not detected by the light sensor as non-visible vehicles.

By comparing the vehicles detected on the one hand by the light sensors, such as a Lidar or camera, and on the other hand by the proximity sensors, it allows to easily distinguish the vehicles which are not visible since they are not detected by the light sensors but only by the proximity sensors.

A second aspect of the disclosure relates to an advanced driver assistance system of a vehicle for detecting non-visible vehicles in the vehicle's environment, for implementing the method according to the first aspect, the system comprising at least one proximity sensor comprising an emitter for emitting a proximity signal capable of propagating through the air along a non-linear path; a receiver in a screening mode to screen and receive any incoming proximity signal; a processor for processing the received proximity signal to detect a non-visible vehicle; and a warning unit for warning a driver and/or the advanced driver-assistance system of the detected non-visible vehicle.

The proximity sensor in some embodiments is an ultrasonic sensor, such as a parking sensor. The system may include a plurality of proximity sensors arranged at the front, rear and sides of the vehicle.

A third aspect of the disclosure relates to a vehicle equipped with an advanced driver assistance system according to the second aspect.

