The prior art discloses a multiplicity of different mono and stereo camera systems for use as ambient sensors in motor vehicle applications. On account of the diverse new opportunities which such camera systems provide in connection with driver assistance systems, they are becoming increasingly widespread. In this context, stereo camera systems are suitable not only for object identification but also, additionally, for distance determination. Similarly, navigation systems—which are usually designed on the basis of GPS—are also present as standard in more and more current vehicles. These navigation systems use received satellite signals to perform location determination and guide the driver to the destination along a journey route which is determined by means of a digital map. The more satellite signals the navigation system receives from as large a number of satellites as possible and the more distinctly these signals are received, the more exactly the location determination can be performed in this case.
Camera systems are usually arranged in the interior of the passenger space, as disclosed in DE 10 2008 061 749 A1, for example. The camera system described therein is mounted in front of the windshield on an upper cross connection of the A pillars. Here, there are good prerequisites for optical ambient identification on account of the field of vision, which is almost unrestricted in the direction of travel. At the same time, the view of the vehicle occupants through the windshield is not restricted or is restricted only a little. To avoid unwanted irradiation of light which enters the camera sensor system from outside a region that is to be monitored, the camera systems based on the prior art are also surrounded by what is known as stray-light protection.
DE 10 2008 020 446 A1 describes a correction apparatus for correcting an internally calculated vehicle position. A camera sensor or an ESP sensor system is used to identify a first position which corresponds to a prominent point on the journey route of the vehicle and to read the associated position from a memory unit. Furthermore, the correction apparatus comprises a position determining unit, e.g. based on GPS, for determining a second position of the vehicle. The ascertained second position can then be corrected using the ascertained first position.
In the course of constant improvement of information capture, information processing and hence also of the reliability of the information, the individual items of sensor information are being increasingly fused in the motor vehicle sector. In this connection, DE 10 2007 058 192 A1 discloses a central controller for a plurality of assistance systems which are provided in a motor vehicle and which, at least to some extent, are equipped with ambient sensors. The central controller is connected to the individual assistance systems at data level and checks the information from an ambient sensor using the information from other ambient sensors. By way of example, the image information from a camera can confirm the interval measurement from a radar sensor. Individual items of sensor information can therefore have a plausibility check performed for them and are available in redundant form. Such coupling of individual signals from different sensors is known as sensor fusion.
The satellite-assisted location determining devices for vehicle applications which are known from the prior art are firstly already subject to disadvantages on account of the known mounting locations for the reception apparatus for the satellite signals. On the basis of the prior art, the reception apparatuses are arranged either in the dashboard, on the roof, in the tailgate or in the side mirrors of the vehicle. In the first case, the propagation path for the signal from the satellite to the reception apparatus is disturbed by the vehicle roof, which results in reduced reception quality and hence reduced location accuracy. In the last three cases, although improved reception quality is available, this is associated with increased installation involvement and likewise increased cost involvement. Added to this are further installation involvement and cost involvement in so far as the location determining device is meant to be coupled to further vehicle sensors as part of increasingly customary sensor fusion.
It is therefore the object of the invention to propose a location determining device which combines comparatively little installation involvement with comparatively good reception quality for the satellite signals and in so doing is capable, without further installation involvement, of coupling the ascertained location information with information from at least one further sensor as part of sensor fusion.
The invention achieves this object by means of the location determining device and the information fusion method described herein.