A LIDAR (Light Detection and Ranging) system is based on the Time of Flight (ToF) method. The Time of Flight method is used to determine the time that a laser pulse needs to overcome a certain distance in a particular medium. In the automotive sector, laser pulses with a length of 3 to 20 nanoseconds are used for the ToF method whereas the shorter laser pulses provide a better accuracy. LIDAR sensors in the automotive industry can reliably detect objects within ranges of up to 300 meters.
A LIDAR sensor emits a short laser pulse to measure the time that elapses until the laser pulse is reflected by an object and subsequently received by the sensor. Due to the constant propagation of light, the distance to the reflecting object can be calculated by measuring the time between the emission, the reflection, and the subsequent receipt by the sensor.
The LIDAR sensor emits a sequence of short laser pulses in different directions and receives them again. This scanning by the laser pulses enables a 2D or even 3D representation of the environment which in the automotive sector is suitable for environmental perception in traffic scenarios.
Strengths of the LIDAR sensors
LIDAR sensors have a high angular resolution and a wide field of view which is invaluable for precise and reliable mid-range detection. Hence, the scanned data can be recorded and with the help of software tools, they can be used to create a model of the vehicle’s surroundings. This model includes the position and velocity of other road users as well as information on the road infrastructure.
The tracking algorithms contained in the sensor’s software are able to determine the position and shape, the velocity, yaw rate, heading direction and many other attributes of the objects. Therefore, the LIDAR sensors can be used as system for measuring distance and velocity.
Furthermore, the LIDAR sensors are also able to detect free spaces in their entire field of view. As an active system, they are independent from any light conditions, so they can be used at any time of the day. In addition to that, LIDAR sensors are the perfect connection between close-range and far-range sensor systems.