Mercedes-Benz: Ten years of PRE-SAFE®: the car with protective reflexes celebrates a special anniversary
Under the microscope: the new sensors. Intelligent networking of eyes and ears
Highly sophisticated sensors and the necessary networked algorithms provide the foundation for innovative new functions. As part of "sensor fusion", DISTRONIC PLUS with Steering Assist, BAS PLUS and the PRE‑SAFE® Brake all employ the same stereo camera and multistage radar sensors.
Mercedes-Benz is making a major leap forward with the introduction of the Stereo Multi-Purpose Camera (SMPC), or stereo camera for short. Just like the Multi-Purpose Camera (MPC) fitted previously, it is positioned behind the windscreen in the vicinity of the rear-view mirror. It has an aperture angle of 45° and is capable of spatial detection of objects moving crossways ahead and pedestrians, and calculating their path. The camera's two "eyes" provide it with a three-dimensional view of the area up to around 50 metres in front of the vehicle, and it is able to monitor the overall situation ahead for a range of up to 500 metres. In this way, the new camera is able to provide data for processing by various systems.
Intelligent algorithms evaluate this information in order to detect and carry out spatial classification of both vehicles that are driving ahead, oncoming or crossing, as well as pedestrians and a variety of traffic signs within a large field of vision.
Whereas the stereo camera's lenses act as the car's eyes, the radar sensors are its ears, so to speak, and provide additional data. The system of radar sensors comprises two short-range radar sensors in the front bumper with a range of 30 m and a beam angle of 80°, which are complemented by a long-range radar (200 m, 18°) including medium-range detection (60 m, 60°). The data from the camera and radars is amalgamated in a control unit in order to provide the system-specific data for the various functions.
Here is a summary of the sensors and cameras:
- 2 x short-range radars at the front (30 m, 80°)
- 1 x long-range radar at the front (200 m, 18°) with medium-range detection (60 m, 60°)
- 2 x short-range radars on the sides at the rear (30 m, 80°)
- 1 x multi-mode radar at the rear (30 m, 80° and 80 m, 16°)
- Stereo camera (Stereo Multi-Purpose Camera, SMPC) located behind the windscreen in the vicinity of the rear-view mirror (effective range 500 m, incl. 3D capability for approx. 50 m, 45°)
- 12 ultrasonic sensors (4 each at the front/rear + 2 each on the left/right in the front and rear bumpers)
- 4 cameras as part of a 360° camera system (1 each at the front in the radiator grille/behind in the handle recess/below in the exterior mirror housings, vertical angle of approx. 130°, horizontal > 180°, resolution 1 MP (1280 - 800 pixels)
An extensive system of additional sensors is able to keep an eye on the current driving state and the driver's reactions. If the sensors detect a hazardous situation, they are able to feed the algorithms for all manner of assistance systems with data in order to provide just the right support for the specific situation.