Wider aperture allows faster reaction when cars cut in front, Height now also measured for improved emergency-brake function, Standardized manufacturing processes reduce manufacturing cost
Many high-performance assistance systems use a radar sensor to map the vehicle’s surroundings. The advantage of these sensors is that they can measure extremely accurately the distance and speed of vehicles on the road ahead. Bosch has now developed a new long-range radar sensor. Like its predecessors, it uses the 77-gigahertz frequency bandwidth. It is also even more powerful, compact, and cost-effective than its direct predecessor. “The new radar sensor can detect obstacles and vehicles cutting in even faster,” says Gerhard Steiger, president of the Chassis Systems Control division. “This means that safety functions such as automatic emergency braking can be triggered earlier.” The fourth generation of Bosch long-range radar sensors, or LRR4 for short, goes into series production in 2014.Wider aperture provides more information about surroundings
The most important technical novelty in the new LRR4 is the number of radar beams used. As in the predecessor model, four generate a bundled beam to the front. They can detect other vehicles at a distance of roughly 250 meters. This allows the ACC adaptive cruise control to be used at speeds of more than 160 kph, and the ACC can make up for large differences in speed without any intervention by the driver. Two additional radar beams extend the aperture to 40 degrees – ten degrees more than the predecessor. This means vehicles cutting in can be detected even earlier, and the ACC can react faster. For even more information, there is also an elevation beam. In concert with the six basic beams, it can estimate the height of the objects detected, which helps to classify them better. The advantage for drivers is that critical situations, especially in urban traffic, are detected and clearly identified earlier. Automatic emergency braking can be triggered earlier, meaning that accidents can be averted altogether or their severity mitigated. Maximum performance comes from the use of two radar sensors installed one on each side of the front of the vehicle. Together, they offer an even wider aperture. As they are not installed dead center, they can detect vehicles cutting in even quicker.
LRR4 integrates comprehensive sensor data fusion
Powerful assistance systems frequently rely on more than one sensor. Like its predecessor, the LRR4 can use its own control unit to process the data from a second, optional radar sensor, from a video camera, and from ultrasound sensors. With the help of powerful software algorithms, this “sensor data fusion” can give rise to a highly detailed “image” – or more precisely, an interpretation of the vehicle’s surroundings. By this, it also detects pedestrians and includes them in its evaluation of the situation, which can help further improve functions such as automatic emergency braking. From 2016, this pedestrian protection will be one of the requirements of the safety tests carried out by the consumer protection organization Euro NCAP. The benefit of such systems has already been proved by the euroFOT field study, initiated by the European Union. Published in 2012, it found that an ACC in combination with a collision warning system can have a positive effect on more than five percent of all freeway accidents involving injury, or even avert them altogether.