b'75A self-driving vehicledepends onThe sensing suite used by the Argothe vehicle is doinglike the rate of ac- ers and shortcomings. Its only in com-its sensing suite like a regular driver needsself-drivingsystem(SDS)reliespri- celeration, orientation, how quickly thebinationthattheseinstrumentsallow hereyesandears.Butwhileapersonsmarily on a combination of lidar, radar,wheels are rotatingrelative to the sur- self-driving vehicles to move safely and range of perception is limited, variable, andand cameras to provide an accurate 3Droundings.Theamalgamationofdataefficiently through the world. We want fi model of its surroundings, day or night,streaming in from all of these devices isour sensors to interact in such a way,lled with blind spotsits called periph-eral vision for a reasona well-designedrain or shine. In addition, the SDS usescalled sensor fusion.saysprincipalscientistDevaRamanan, sensing suite can reveal a precise, 360-de- nonperceptionsensorslikeinertialJustlikeeachsenseinthehumanthat the whole is greater than the sum gree picture of the world around us. It is asmeasurementunitsandwheelspeedbody has diff erent strengths and weak- of their parts.close as we can come to an all-seeing eye. sensors to gain a clearer picture of whatnesses,eachsensorhasitssuperpow-VISION Lidar Radar Cameras Internal Sensors The accuracy of the 3DRadar, or radio detection andArgo self-driving test vehicles models enable autonomousranging, works very similarlyare equipped with threeJust like our inner ear helps vehicles not only to perceiveto lidar, but employs radiodiff erent types of camerasus tell when were swaying the road, vehicles, and pedes- waves instead of pulsedforming a ring of high-resolu- on a boat even if were not trians, but also to distinguishlaser light. Like lidar, radar istion cameras. The fi rst type,actively moving our bodies, among vehicle types, vulner- used to detect objects andstereo cameras, are installedthe sensing suite relies on able road users (everythingdetermine their distance,on the front of the vehicle andinternal, nonperception from cyclists to scooter ridersangle, and velocity. Unlikehelp the self-driving systemsensors (proprioception) so to stroller-pushers), animals,lidar, radar can determine thedetect the depth of an image.that the SDS knows where the or other objects both movingrelative speed of a moving ob- Imagine holding an object invehicle is and how its moving. and stationary.ject using Doppler frequencyfront of your face and closingThis is especially crucial for The self-driving systemshiftthe change in frequencyone eye at a time. The objectunusual scenarios, like if its fuses data from long-rangeof a wave in relation to thewill appear to jump from onenavigating a road slippery lidar sensors that ensure a ve- wave sourcewhich is criticallocation to another, but whenfrom rain, driving over a large hicle can travel safely at high- in predicting how an objectthat object gets farther away,pothole, or swerving to avoid er speeds with short-rangewill continue to move.the size of the jump shrinks.an obstacle. lidar, capable of detectingBecause radar waves areStereo measurements workSpecifi cally, the SDS objects (like ride-hail passen- less sensitive to factors likethe same way, identifying theuses inertial measurement gers waiting by the curb) thatsnow, fog, rain, and dust, ra- same pixel in two separateunits, accelerometers, and are a matter of inches or feetdar is optimal in more variedbut nearly overlapping camer- rate gyroscopes, for away, to create accurate 3Dconditions and environmentsas, and then creating a depthproprioception, helping track models of the surroundingsthan lidar. And since radiomap of the surroundings byposition changes and the both near and far.waves have less absorp- measuring the distance be- direction the vehicle is tion than light waves whentween pixels from one cameraheading in real time. Wheel contacting objects, it returnsto the next. speed sensors combined images with higher fi delityThe second, far-fi eldwith information from the at greater distances thancameras, like their nametachometer help the SDS lidar. However, in general,implies, detect objects fartherunderstand whether the radar uses longer microwaveaway from the vehicle. Thevehicle is moving the waynal type, near-fi eld camer- that is expected. For frequencies, which havefilower resolution than lidaras, detect objects closest toexample, if a vehiclesand therefore doesnt returnour vehicle, like lanes in theengine speed doesnt match as precise a 3D model of itsstreet, curbs, or even pedes- the expected forward motion, surroundings as lidar; hencetrians, animals, and vehiclesthe SDS knows that some-the need for both types ofwhen they get close enough.thing is awry. sensors, working in concert. Operating in a 360-degree ring around the vehicle, these cameras help detect fi xed and moving objects on all sides, eliminating blind spots and detecting objects too close for radar and lidar to accu-rately capture. FullBook_Mar24.indb 75 4/25/21 6:43 PM'