The Sensors Behind The Navigation, Driving And Performance Of Autonomous Vehicles

The self-driving, autonomous vehicle has been getting lots of attention due to significant development efforts and dramatic progress made by companies such as Google. While the widespread use of autonomous vehicles on public roads is probably still years away, these vehicles are already being employed in ‘constrained’ applications such as open-pit mines and farming.

- Bill Schweber

Among the many technologies that enable autonomous vehicles is a combination of sensors and actuators, sophisticated algorithms, and powerful processors to execute software. The sensors and actuators in an autonomous vehicle fall into three broad categories:

Navigation and guidance (where you are, where you want to be, how to get there)

Driving and safety (directing the vehicle, making sure it operates correctly under all circumstances, and follows the rules of the road)

Performance (managing the car’s basic internal systems). There are dozens of sub-systems and hundreds of specialised sensor channels under these three categories. Let’s look at a few of them.

Goal No. 1: Know where you are going

Navigation has been a human concern since the earliest days. It addresses two related questions: where you are now, and what paths are available to get to where you want to be. Instruments and techniques such as the compass, sextant and dead reckoning in the past, as well as the more current LORAN radiolocation, are examples of what has been used, with varying degrees of accuracy, consistency and availability.

For the autonomous vehicle, the navigation and guidance subsystem must always be active and checking how the vehicle is doing, in relation to the final goal. For example, if the original ‘optimum’ route has any unexpected diversions, the path must be re-computed in real-time to avoid going in the wrong direction. Since the vehicle is obviously constrained to roadways, this takes much more computational effort than simply drawing a straight line between A and B.