As part of its work on developing new safety and driver assistance systems, Bosch will introduce a new mid-range 77 GHz radar sensor for front- and rear-end applications and a new stereo-video sensor.
77 Ghz radar. A leading European automaker is slated to deploy the new Bosch MRR rear mid-range radar sensor, which can precisely locate vehicles in blind spots or approaching from behind, in 2014. Compared to current 24-gigahertz solutions, this sensor is much more precise, with up to three times the ability to distinguish between objects and up to five times more accurate measurement of speed and distances, Bosch says.
With a range of up to 100 meters and an aperture angle of up to 150 degrees, the sensor is able to detect dangerous situations in the area to the rear of the vehicle at an early stage. Its exceptional distance resolution and accurate speed measurement ensure the driver knows exactly what is going on.—Gerhard Steiger, the president of the Bosch Chassis Systems Control division
Two sensors, hidden one each to the left and right in the vehicle’s rear bumper, monitor the area beside and behind the vehicle. If another car is in the blind spot or is approaching at speed from behind, a lane-change assistant can warn the driver in time. Reversing out of a parking space no longer poses a problem, even when the driver’s view is blocked by obstacles. The MRR rear reliably warns of any approaching vehicles.
Based on the expertise Bosch has accumulated over three generations of radar design, MMR rear allows the automaker to integrate a wide range of safety and convenience functions. The technical basis for this is provided by bistatic frequency-modulated continuous-wave (FMCW) radar with four receiver channels.
Its higher operating frequency, wider modulation bandwidth, and four receiver channels make the quality of its continuous positioning far superior to standard 24-gigahertz systems.
The relative speed and distance of another vehicle is measured using the Doppler effect—the frequency shift between the emitted and received signal—and the time difference between the two signals. The vehicle’s current position can be determined by comparing the reflected signals picked up by the four discretely positioned receiver antennas.
The silicon-germanium technology used in the integrated high-frequency circuits does without moving parts. With a compact design that makes use of space-saving planar arrays, the system is easy to integrate into a vehicle’s body, for example hidden behind the bumper.
The front-end version of MRR, which was developed in parallel, has an even greater range of up to 160 meters, with an aperture angle of up to 45 degrees. On the basis of just one sensor, an emergency braking system working in conjunction with the ESP electronic stability program can take action to avoid or reduce the severity of an accident. Its data can also be fed into the ACC adaptive cruise control.
This function automatically brakes and accelerates to maintain a predetermined distance from the vehicle in front, and can tell drivers how far away they are from the vehicle in front.
Stereo-video sensor. Bosch engineers have succeeded in using a new stereo video camera to give driver assistance systems the capability of “seeing” in binocular vision—a capacity that enables the calculation of object sizes and distances and perceive longitudinal motion.
Stereo technology opens up new potential for video-based safety systems. A mono video camera requires extensive training before it can distinguish between different types of objects, such as pedestrians and cars, in its image field. In contrast, a stereo video camera can measure and detect all the obstacles based only on their movement and distance.—Gerhard Steiger
Endowed with binocular vision, the sensor can measure distances to other objects using the video signal alone. On the basis of this, Bosch is developing functions that can independently take evasive action or steer the vehicle through a construction site. These will work in conjunction with existing assistance functions such as ACC adaptive cruise control and automatic emergency braking.
The new Bosch video camera supplies data for many different tasks. The information it provides can reduce both the risk and the consequences of collisions with vehicles, pedestrians, and cyclists at speeds of up to 80 km/h (50 mph).
As a result, the stereo camera data alone can be used to trigger an automatic emergency braking process. If an accident cannot be prevented, the speed of impact and thus the severity of the accident can at least be minimized—and by priming the passenger restraint system, airbags and seat belt pretensioners can be deployed in the optimum way.
The stereo system can of perform all the tasks typically associated with a mono video camera, such as recognizing traffic signs, helping drivers to stay in their lane, and automatically adjusting a vehicle’s headlights to take account of vehicles in front and oncoming traffic.
By integrating the control unit for image processing and function control directly in the camera housing, the Bosch engineers have created a compact system. With a 12-centimeter baseline distance—the distance between the optical axes of the lenses—the Bosch stereo camera may well be the smallest system of its kind currently available in the field of automotive solutions, the company sugests. As a result, it is easier for automobile manufacturers to integrate into their vehicles.
Each of the two CMOS (complementary metal oxide semiconductor) image sensors has a resolution of 1.2 megapixels. With its high-quality lens system, the camera is able to capture an angle of view of 25 degrees vertically and ±25 degrees horizontally, and offers a 3D measurement range in excess of 50 meters. The highly light-sensitive image sensors are capable of processing very high contrasts and cover the full spectrum of light visible to the human eye.