Field of the Invention

The invention relates to an automatic collision notification system, the invention being applicable with particular advantage to motor vehicles .

A number of systems have recently been proposed which include an in car transmitter, arranged to emit an emergency signal in the event of an accident. Typically the emergency signal is transmitted to the emergency services, in particular the police. These are known under a number of names including 'Emergency Call', 'MayDay' and 'VEMS ' . Such systems typically link with signals from Global Positioning Satellites ( GPS) often used in in-car navigational systems, to give the emergency services the ability to pinpoint the location of the vehicle accurately. Typically such systems emit a signal on actuation of an airbag, since this is an indicator that some impact has occurred. However it is possible that airbags can be actuated when the accident is not severe, where there are no other road users involved, and where the attendance of the emergency services is not strictly necessary.

A number of radar systems have been proposed for installation in motor vehicles for detecting objects around a vehicle. Transmitters and receivers are mounted upon the vehicle to detect the presence or approach of objects in a particular direction to be used to help to warn an occupant of a potential collision. Typically, such systems have been developed for collision warning and parking.

Summary of the Invention

According to the invention there is provided an improved automatic collision notification system comprising a radar

sensing system including at least one radar transmitter and receiver arranged to detect the presence of an object in a pre-determined area relative to the vehicle and to detect the velocity and direction of movement of the object relative to the vehicle, a collision prediction unit coupled to the radar sensing system which calculates the impact velocity of the impending collision to provide an accident severity indicator, the collision prediction unit being coupled to an accident notifier arranged to transmit a signal receivable at a station remote from the vehicle, the signal emitted transmitting the information that a collision has occurred and the severity of the collision.

Thus this system ensures that the information passed on to the emergency services is fuller and gives them a more complete picture. This could reduce the possibility of trivial call-outs and higher prioritisation for high severity accidents.

The system according to the invention can be provided as a separate unit to the commercially available systems or can be incorporated into the systems available for emergency Call-up on accident occurrence as an add-on providing further information. Preferably the collision prediction unit also calculates the trajectory of the impact.

The predetermined area in relation to the vehicle in which the presence of an object is to be detected depends on the nature of the vehicle. However to be comprehensive, this will have to encompass an envelope surrounding the vehicle.

Preferably the system includes at least two radar transmitters and receivers, which are impulse radar transmitters and receivers . In this context the term 'impulse radar' is intended to encompass any radar signal of short radio frequency without a carrier wave, and includes radar sometimes referred to as 'broadband radar' . A typical

impulse radar sensing system is described in published specification O90/13048.

Such a system can be used to track accurately the path of an object outside the vehicle to accurately predict the potential of a collision, its likely position and time before impact.

Although the radar sensing system may be used in a vehicle, purely for use in the automatic collision notification system, the invention is applicable with particular advantage to a vehicle in which the radar sensing system is used also for providing driver information and warnings, such as a parking aid. The advantage is that the same sensors are multifunctional.

Preferably the radar sensing system is part of a collision warning system as described in copending PCT application number GB97/01728. Such a system is able to look around the vehicle to detect obstacles about the vehicle and to use the signals detected in a number of collision warning modes.

Brief Description of the Drawings

An automatic collision notification system in accordance with the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:-

Figure 1 is a schematic illustration of a typical collision warning system;

Figure 2 is a schematic block diagram of the automatic collision notification system;

Figure 3 is a schematic view of the predetermined area scanned by the radar receiver; and,

Figure 4 is a schematic plan view of a vehicle illustrating the position of the sensors and receivers.

Description of the Preferred Embodiment

The automatic collision notification system 1 illustrated in the drawings comprises a radar sensing system 3 including at least one radar transmitter and receiver arranged to detect the presence of an object in a predetermined area relative to the vehicle 4 and to detect the velocity and direction of movement of the object relative to the vehicle 4, a collision prediction unit 5 coupled to the radar sensing system 3 which calculates the impact velocity of the impending collision to provide an accident severity indicator, the collision prediction unit 5 being coupled to an accident notifier 7 arranged to transmit a signal receivable at a station remote from the vehicle, the signal transmitting the information that a collision has occurred and the severity of the collision.

Here the collision prediction unit 5 also calculates the trajectory of the impact.

The radar system 3 comprises four sensors 9 shown in figure 3 mounted at the corners of the vehicle in the region of the bumper. Each sensor 9 comprises an impulse radar transmitter and receiver. This arrangement of four sensors allows the envelope around the vehicle to be monitored.

The radar sensing system monitors continually the zones of concern illustrated in figure 3 for intrusion by other vehicles or other obstacles. The predetermined areas are front of vehicle, rear of vehicle, drivers side and passenger side. The sensors 9 are used in pairs to track the trajectory of targets within their field of view. Time to impact is calculated using knowledge of relative velocities

of the vehicle and target. This information is then fed to the collision prediction unit 5.

As illustrated in figure 1, the location of the vehicle 4 is pinpointed by a Global Positioning Satellite 11 which produces a signal 13 part of which pinpoints the position of the vehicle which is transmitted from the vehicle 4 to a central receiving antenna 15 which transmits relevant information to the emergency services 17.

In this case the collision notification system 1 is part of an existing system, VEMS ( although it could equally be part of the Emergency Call or MayDay systems also available) . Such a system is arranged to send a signal forming part of the signal 13 transmitted to the antenna 15, on actuation of the airbag to indicate that an accident has occurred.

The signal 13 also includes a signal which indicates the severity of the collision so that the emergency services are given as full a picture as possible, with the fact that an accident has occurred, an indicator of severity and the location of the accident.

This helps the emergency services to provide aid quickly and efficiently without needing to await a report of the accident.