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Application of LIDAR in autonomous vehicles
High-performance laser system technology that enables the operation of light detection and ranging systems (LIDAR) has become a standard resource for the advancement of self-driving vehicles. The LIDAR technique relies on infrared laser systems, enabling autonomous vehicles to navigate by creating a real-time, 3D representation of their surroundings.
How LIDAR laser systems work
The laser technology includes the combination of pulsed fiber laser and single-pixel sensors or high-powered laser system flash illumination, applying the time of flight cameras to create the required 3D images. The laser system can carry out the travel time measurement of the light produced by a laser beam from the autonomous vehicle to the target and back to the vehicle.
Advantages of laser technology for LIDAR
This laser system technology offers a highly attractive benefit for LIDAR manufacturers, that is, increased laser system power, resulting in the opportunity for 3D maps to capture more objects and scenery from longer distances. The most important thing is eye safety, which is why short pulses produced by the laser beam play a crucial role.
Rapid pulsing (for example, more than 1 million times per second), more data points, and better signal quality are presented since the fast rise and fall times are essential.
Recent developments in LIDAR lasers
The recent development has the target to transmit LIDAR power emitted by the laser beam of 120W per channel “in a four-channel SMT package delivering >480W peak power with approximately 2 ns full-width half maximum (FWHM) pulses and <1 ns rise and fall times”.
Laser wavelengths used in LIDAR
LIDAR technology employs two primary wavelengths in laser systems: 905 and 1550 nm, each with its advantages. For example, a CMOS or other silicon detector can identify a 905 nm laser beam; the cost becomes lower, and the complexity is reduced. Laser systems at 1550 nm can be detected by silicon photomultipliers and, eventually, by indium gallium arsenide detectors; however, they present problems at the 105°C temperature required for automotive qualification, as well as challenges for eye safety.
Role of multichannel laser systems
Multichannel laser systems are necessary because the application of eight laser modules in individual firing will provide 1% resolution or 15 cm steps, whereas the minimum amplitude and dynamic range is virtually 18 dB when applying a 1 ns time of flight. In fact, based on the mentioned advantages, it is better to use 05 nm multichannel high-power lidar laser systems with nanosecond pulses.
Hybridized mode for reliability
There is an opinion that the presented laser technology should have a hybridized mode including short transmitted pulses with a slightly longer duration receiver “window”, resulting in a more reliable laser system. The main obstacle of LIDAR technology was overcome due to the opportunity to transmit shorter pulses that allowed for optimal eye safety, thermal management, and consequently, high resolution.