The ears and eyes of self-driving cars.

Exploring the modern sensors used in self-driving cars.

 A self-driving or autonomous car is a car driven by its internal computers with the assistance of other electronic devices. It uses sensors that are fixed in the front and at the rear of the car. cutting-edge technologies and modern car sensors are used in today’s transportation field to see and sense the surrounding environment. Cars become more automated, computerized, and more luxurious.

What are the main objectives and advantages of the self-driving car?

The self-driving car is designed to eliminate injuries, accidents, crushing, and fatalities resulting from human mistakes while driving their cars. These mistakes could be, for example, texting during driving or sleeping during driving due to exhaustion, driving for too long, and waking up for long times.

Besides that, the significant impact on the cost results from these accidents starting from injury treatment healing cost, car repair, and the social impact for fatalities. The self-driving car enables people who do not drive cars to go to their destination safely like blond people and People in wheelchairs.

Humans and self-driving cars share the same concept when driving cars. The difference between humans and self-driving cars is that the human can bypass, override, or ignore the warning alarms of the car. But the self-driving car will stop and keep stopping. The ADAS (advanced drive assistance system) supports eliminating the risks coming from human errors (we will make a separate article for the ADAS because of its importance).

The driving procedure for any modern car is as follows:

• Sensing all the car engine internal parameters like temperature, fuel, and oil levels. It also senses the surrounding condition and objects' size, shape, and position along the roads.
• Check and evaluate the sensed parameters and confirm it is ok by comparing it with a slandered predetermined value.
• If all these measured parameters are OK and within limits, the human driver will drive the car and the autonomous car will start to move.
• Both humans and cars will monitor the measured parameters during the car driving where the human will check the values and monitor it while the self-driving car’s computer will check the health of the parameters.
• The human will act on his own decision for speed up or down, choosing the best route and when stopped while the autonomous car will act based on its computer rules.

What are the sensors used in self-driving cars?

LIDAR (Light Detection and ranging).
Lidar is the most commonly effective sensor used in self-driving cars. It is a device that uses a laser ultraviolet light beam to detect the surrounding area around the self-driving. It builds a 3D map for any surrounding environment by using a smart communication system called integrated photonics tools.

LIDAR is an active sensor where the laser light emitted by the lidar hits any object around the car, the device will receive the reflected beam and calculate its orientation. The basis of calculation is that the speed of laser light is known and the device will calculate the time that the beam takes from the source till reflected and sensed by the device which is equal to the multiplication of speed by time.

The photonics is the item that is responsible for the short pulses to complete the 3D map. This device is used with small objects and could be used with non-metallic objects. But it could be affected during the night or the bad weather days.

RADAR (Radio Detecting and ranging)

It uses the radio frequency wave to determine the distance between the self-driving car and the surrounding objects. It is an active sensor that sends the radio frequency wave and receives the reflected wave then the distance is calculated. 

The radar device is good for the weather as the radio frequency can be transported for long distances through rain or fog without fading away. it is also more accurate compared to the camera. Radar is good and cheap but it has the concern that for the vertical resolution, it leads to having more antennas.

Camera system.

The camera is the highest resolution sensor in self-driving cars using sensor fusion and can submit a huge amount of information about the surrounding environment. it used to capture photos or videos and analyze them through a special digital image processing where the option of the distance and volume of the surroundings are be configured and analyzed. Cameras can detect traffic or road signs, unlike the lidar which cannot recognize it.

Ultrasonic Sonar system.

It uses the ultrasonic wave and calculates the time it takes starting from emitting the wave till received by the device. Because of the physical properties of the sound wave, it is considered not accurate although its advantage of working when the visibility is low. The ultrasonic sensors are widely used as parking sensors in modern cars that park automatically.

As artificial intelligence (AI) can handle multiple tasks at the same time, self-driving cars are using (AI) to utilize all the huge data coming from the sensors. The self-driving car supercomputer collects all the data from sensors about the surrounding area to determine any obstacle’s size and volume and follows a special complex algorithm in the self-driving car supercomputer. This algorithm analyzes the data collected by sensors in real time related to speed, predicted paths, and relative distance.

How does the self-driving car work?

After the self-driving car computer checks and analyzes the data, the car will start moving if the parameters indication is ready for start. If it is not the car will not move. During the running of the car, the automatic control system of the car‘s computer controls the operation and performance of the car.

The speed up or down of the car is based on the sensed parameter and the condition prepared for the car speed control loop. There is another control loop inside the self-driving car which is the position where the car uses the Global positioning system to determine the position of the car, the destination, and the traffic condition where the computer can start evaluating the route situation and can modify it to another rout with low traffic. During the car moving the car’s computer monitors the engine and the car's internal parameters as also the external surrounding condition.